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2003 Fluoride Abstracts. Part 1.

Abstracts for the following years:
Part 1 - mainly biochemistry and physiology (brain, hormonal, G-proteins, etc.)
Part 2 ("b") - all other

2007

2007-b

2004

2004-b

2001

2001-b

1998

1998-b

1995

1995-b

1992

1992-b

1989

1989-b

1986

1986-b

1983

1982

1976 -
1977
1970 -
1971

2006

2006-b

2003

2003-b

2000

2000-b

1997

1997-b

1994

1994-b

1991

1991-b

1988

1988-b

1985

1985-b

1981

1980

1974 -
1975
1968 -
1969

2005

2005-b

2005-b continued

2002

2002-b

1999

1999-b

1996

1996-b

1993

1993-b

1990

1990 -b

1987

1987-b

1984

1984-b

1979

1978

1972 -
1973
Up to
1967

Full free report available at: http://www.fluoride-journal.com/03-36-2/362-084.pdf

Fluoride Vol. 36 No. 2 84-94 2003 Research Report

EFFECT OF FLUORIDE IN DRINKING WATER ON CHILDREN’S INTELLIGENCE

Q Xiang (a), Y Liang (a),L Chen (b), C Wang (b), B Chen (a), X Chen (b), M Zhou (c)

(a) For Correspondence: Dr Xiang Quanyong, Department of Occupational Health, School of Public Health, Fudan University (Formerly Shanghai Medical University), Shanghai, 200032, China. E-mail: quanyongxiang@yahoo.com.cn or yxliang@shmu.edu.cn.
(b) Center for Disease Control and Prevention, Jiangsu Province, China.
(c) Center for Disease Control and Prevention, Sihong County, Jiangsu Province, China.

SUMMARY: The Intelligence Quotient (IQ) was measured in 512 children,
aged 8–13 years, living in two villages in Sihong County, Jiangsu Province,
China, differing in the level of fluoride in their drinking water. In the high-fluoride village of Wamiao (water fluoride: 2.47±0.79 mg/L; range: 0.57–4.50 mg/L), the mean IQ of 222 children was significantly lower (92.02±13.00; range: 54–126) than in the low-fluoride village of Xinhuai (water fluoride: 0.36±0.15 mg/L; range: 0.18–0.76 mg/L), where the mean IQ of 290 children was higher (100.41±13.21; range: 60–128). The children’s IQs were not related to urinary iodine, family income, or parent’s education level. Higher drinking water fluoride levels were significantly associated with higher rates of mental retardation (IQ <70) and borderline intelligence (IQ 70–79). The Benchmark Concentration (BMC) for the concentration-response relationship between IQ <80 and the drinking water fluoride level was 2.32 mg/L, and the lower-bound confidence limit (BMCL) of the BMC was 1.85 mg/L. Taking dental fluorosis and other sources of dietary fluoride into account, the reference value con-centration (RfC) for fluoride was calculated to be 0.925 mg/L, which is very close to the current national Chinese standard of <1.0 mg/L. In endemic fluorosis areas, drinking water fluoride levels greater than 1.0 mg/L may adversely affect the development of children’s intelligence.

NOTE: Two authors of this study had an update published as a Letter.

Full text available at: http://www.fluoride-journal.com/03-36-3/363-198.pdf

Fluoride Vol. 36 No. 3 198-199 2003 Letter to the Editor

BLOOD LEAD OF CHILDREN IN WAMIAO–XINHUAI INTELLIGENCE STUDY

Dr Quanyong Xiang and Prof. Youxin Liang

Excerpt: As an additional part of our investigation of an association between fluoride
in drinking water and children’s intelligence in two villages of Sihong County, Jiangsu Province, China,1 we have now determined blood lead levels of children in that study.

Blood samples (80 µL) were collected on June 18 and 19, 2003 from the
index finger of 71 randomly selected 8 to 13 year-old children in the high
fluoride village of Wamiao and 67 children of the same ages in the low fluoride
village of Xinhuai. The samples were preserved in clean plastic centri-fuge
tubes containing 0.64 mL of Triton X-100. Blood lead was measured
within one week by atomic absorption spectrophotometry.2

The results, as summarized in the table below, show there is essentially no
difference between the two villages in blood lead concentrations of the children
...


Full free report available at: http://www.fluoride-journal.com/03-36-4/364-217.pdf

Fluoride Vol. 36 No. 4 217-228 2003

Editorial Review

FLUORIDE AND OXIDATIVE STRESS

Dariusz Chlubek

For Correspondence: Dept. of Biochemistry and Chemistry, Pomeranian Medical University al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland.
E-mail: dchlubek@pam.szczecin.pl

This Editorial Review is worth reading. The author presents the following Tables:

Table 1. Influence of fluoride on superoxide dismutase (SOD) activity in fluorotic humans (in order of publication)

Table 2. Influence of fluoride on superoxide dismutase (SOD) activity in fluoride- intoxicated animals (in order of publication)

Table 3. Influence of fluoride on glutathione peroxidase (GSH- Px) activity in fluorotic humans (in order of publication)

Table 4. Influence of fluoride on glutathione peroxidase (GSH- Px) activity in fluoride- intoxicated animals (in order of publication)

Table 5. Influence of fluoride on malondialdehyde (MDA) formation in fluorotic humans (in order of publication)

 

Full free report available at: http://www.fluoride-journal.com/03-36-4/364-263.pdf

Fluoride Vol. 36 No. 4 263-266 2003 - Research Report 263

FLUORIDE CONTENT IN SOFT TISSUES AND URINE OF RATS EXPOSED TO SODIUM FLUORIDE IN DRINKING WATER

I Inkielewicz (a), J Krechniak (a,b)

(a) Department of Toxicology, Medical University of Gda n´ sk, Poland.
(b) For Correspondence: Dept. of Toxicology, Medical University of Gda n´ sk, 80-4 1 6, Gda n´ sk Al. Gen. Hallera 1 07, Poland.

SUMMARY: Eight-week old male Wistar rats weighing about 180 g were given sodium fluoride in drinking water at a concentration of 5 and 25 mg F – /L for 12 weeks. Control animals received tap water containing 0.3 mg F – /L. The fluoride content in liver, kidney, brain, testis, and serum was determined at the beginning of the experiment and after 2, 4, and 12 weeks of exposure. Urinary fluoride concentration was determined weekly. In all the tissues and organs the fluoride content increased in a dose-dependent and a time-dependent manner. In animals receiving the higher dose of sodium fluoride the increase after 12 weeks of exposure was about two-fold in serum, seven-fold in liver and kidney, nine-fold in brain, and twelve-fold in testis. Urinary fluoride also increased from the beginning of exposure in a dose-dependent manner.

 

Full free report available at: http://www.fluoride-journal.com/03-36-4/364-231.pdf

Fluoride Vol. 36 No. 4 231-240 2003 - Research Report 231

THE INFLUENCE OF SODIUM FLUORIDE AND SODIUM HEXAFLUOROSILICATE ON HUMAN LEUKEMIC CELL LINES

Boguslaw Machalinski (a), Magdalena Baskiewicz-Masiuk (a), Bogna Sadowska (a), Anna Machalinska (b), Mariola Marchlewicz (b), Barbara Wiszniewska (b), Iwona Stecewicz (a)

For Correspondence: Boguslaw Machalinski, MD, PhD., D.Sci.
(a) Department of General Pathology, Pomeranian Academy of Medicine (PAM), Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland. E-mail: machalin@sci.pam.szczecin.pl
(b) Department of Histology and Embryology, PAM, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland.

SUMMARY: Although potential toxic effects of sodium fluoride on early progenitor and stem cells have been reported previously, surprisingly few investigations have examined the effects of fluoride on human leukemic cells. To address this need, four different human leukemic cell lines (HL-60, HEL, TF-1, and K562) were exposed to increasing levels (0, 0.24, and 1.19 mM F) of two forms of fluoride: sodium fluoride (NaF) and sodium hexafluorosilicate (Na2SiF6). Because of its widespread use in water fluoridation, Na2SiF6 was investigated in addition to NaF. The early response effect of Na2SiF6 was greater, and in several cases significantly greater, than NaF on clonogenic growth and the induction of apoptosis in all four cell lines. These findings show that human leukemic cells can be influenced and damaged by fluorine compounds.


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14761523&dopt=Abstract

Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2003 Apr;21(2):102-4.

[Studies on fluoride concentration and cholinesterase activity in rat hippocampus]

[Article in Chinese]

Zhai JX, Guo ZY, Hu CL, Wang QN, Zhu QX.

School of Public Health, Anhui Medical University, Hefei 230032, China.

OBJECTIVE: To study the accumulation of fluoride in rat hippocampus and its effect on cholinesterase activity.

METHODS: Rats were subchronically exposed to NaF, and fluoride concentration and cholinesterase activity in rat hippocampus were determined.

RESULTS: Fluoride concentration in rat hippocampus was significantly correlated with the dosage of fluoride, and there were significant differences among high dosage group [(13.03 +/- 1.79) micro g/g], low dosage group [(9.83 +/- 0.92) micro g/g] and control [(8.27 +/- 1.11) micro g/g], P < 0.01.Acetylcholinesterase activities among three groups [(0.111 +/- 0.031) micro mol/mg, (0.143 +/- 0.025) micro mol/mg, (0.183 +/- 0.027) micro mol/mg] were also significantly different (P < 0.01), which was negatively correlated with fluoride concertration in rat hippocampus (r = -0.700, P < 0.01). The activity of butylcholinesterase in high dosage group [(0.041 +/- 0.010) micro mol/mg] was different from that of control [(0.067 +/- 0.025) micro mol/mg, P < 0.05], but the activity was not significantly related with fluoride concertration in rat hippocampus (r = -0.317, P = 0.094).

CONCLUSION: Fluoride may go through the blood-brain barrier and accumulate in rat hippocampus, and inhibit the activity of cholinesterase.

PMID: 14761523 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12963002&dopt=Abstract

Food Chem Toxicol. 2003 Nov;41(11):1501-8.

Effects of fluoride on Xenopus embryo development.

Goh EH, Neff AW.

Associate Professor of Pharmacology and Toxicology, Indiana University School of Medicine, Medical Sciences Program, Jordan Hall 009A, 47405, Bloomington, IN, USA

Fluoride was first associated with fetal malformation shortly after water fluoridation was initiated in the 1940s. Since many chemicals can interact directly with the embryo to cause malformation, the effects of fluoride on embryonic and fetal development were investigated. The effects of sodium fluoride on the development of frog embryos were studied under conditions described by the Frog Embryo Teratogenesis Assay-Xenopus (FETAX), a screening assay for teratogens. The most prominent malformations caused by sodium fluoride are reduction in the head-tail lengths and dysfunction of the neuromuscular system of the tadpoles. The values for LC(50), EC(50), and minimal concentration to inhibit growth (MCIG) of sodium fluoride met the limits established for a teratogen in frog embryos, showing that sodium fluoride is a direct acting teratogen on developing embryos. Since FETAX has a high degree of success in identifying mammalian teratogens, the observed teratogenic action of sodium fluoride on frog embryos would indicate a strong possibility that sodium fluoride may also act directly on developing mammalian fetuses to cause malformation.

PMID: 12963002 [PubMed - in process]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14635268&dopt=Abstract

J Appl Toxicol. 2003 Nov-Dec;23(6):437-46.

Histopathological and biochemical changes in lung tissues of rats following administration of fluoride over several generations.

Aydin G, Cicek E, Akdogan M, Gokalp O.

Suleyman Demirel University Faculty of Medicine, Department of Pathology, Isparta, Turkey.

The possible effects of multigenerational administration of sodium fluoride (NaF) via drinking water on lung tissue morphology and biochemistry and body and lung weight were investigated in second-generation adult male rats. For this purpose we selected 45 Albino adult Wistar rats in nine cages, each of which consisted of four females and one male. Twenty-eight pregnant rats were selected for the experiment, divided into four groups of seven rats given 1 (control group), 10, 50 and 100 mg l(-1) NaF in drinking water during the gestation period. After gestation the rats had 165 pups in total. The mothers received fluoridated water during the lactation period and the offspring of the first generation had access to fluoridated water during the suckling period (21 days) and after the weaning period (30 days) until they became mature and at the start of the second part of the experiment. During this time 23 pups died and 79 female and 63 male first-generation rats survived. These first-generation rats were then used to obtain the second-generation offspring in the same manner as before, which were subjected to the same treatments. At the end of 6 months the rats were sacrificed and autopsied. Serum fluoride levels and the activities of principal antioxidant enzymes were determined in lung tissue samples taken from all groups. In addition, the lung tissues were submitted for histopathological examination. Histological findings showed alveolar congestion, alveolar cell hyperplasia and necrosis, prominent alveolar septal vessels, epithelial desquamation and macrophages in the alveolar spaces in the experimental groups. Additionally, there were inflammatory infiltrations in peribronchial, perivascular, intraparenchymal and respiratory tract lumen; intraparenchymal hyperaemic vessels; respiratory epithelial desquamation and proliferation; intraparenchymal thick valled vessels; parenchymal fibrosis; bronchiolitis; pneumonic and focal emphysematous areas. Furthermore, the lung parenchyma was observed to have a distorted appearance with loss of alveolar architecture. These histopathological findings were more pronounced for the rat groups of 50 and 100 mg l(-1) fluoride. No significant histopathological changes were observed in the rats of the control group. The increased activities of superoxide dismutase (SOD) and reduced glutathione peroxidase (GSH-Px) and the decreased activity of catalase (CAT) in the lung tissues with 10 mg l(-1) fluoride might indicate activation of the antioxidant defence mechanism. The decrease in SOD, GSH-Px and CAT activities with 50 and 100 mg l(-1) fluoride and the increase in thiobarbituric acid-reactive substance levels might be related to oxidative damage that occurred in the lung. This multigenerational evaluation of the long-term effect of different doses of fluoride intake through drinking water on lung damage shows that the lung tissues were damaged, there was emphysema and inflammation of lung parenchyma associated with loss of alveolar architecture and the degree of lung damage seemed to correlate with the increased dosage of fluoride. A similar relationship was observed between the degree of lung damage, body and lung weight and serum fluoride levels according to the fluoride dose. Therefore, these results contribute to a better understanding of chronic fluoride toxicity in lung tissue of second-generation rats, especially via drinking water, and the biochemical findings were in agreement with histological observations. In addition, increased fluoride concentration did not affect reproduction or the number of pups dying but the body weight and lung weight ratios were affected by the high dose of fluoride in a dose-related pattern. Copyright (c) 2003 John Wiley & Sons, Ltd.

PMID: 14635268 [PubMed - in process]


Forensic Science International
Volume 137, Issues 2-3 , 26 November 2003, Pages 209-214

Bone as a biomarker of acute fluoride toxicity

Léa Maria Bezerra de Menezes (a), Maria Cristina Volpato (b), Pedro Luiz Rosalen (b) and Jaime Aparecido Cury (b)

(a) Faculty of Dentistry, Federal University of Ceará, Rua Alexandre Baraúna 949, CEP 60430-160, Fortaleza, CE, Brazil
(b) Department of Physiological Sciences, Faculty of Dentistry of Piracicaba, University of Campinas, Av. Limeira 901, Piracicaba, SP 13414-903, Brazil

The use of bone as a biomarker for chronic and acute exposure to fluoride salts has been suggested, but there are no data published about its use to evaluate lethal intoxication. One hundred and sixty rats were divided into eight groups that received a single oral intubation dose from 0 (control) to 90 mg F/kg as NaF. The animals’ time of death was recorded and their femurs were removed for fluoride analysis. Acid-soluble fluoride was determined in the whole bone and on the surface (periosteal), using an ion specific electrode. The data showed a statistically significant relationship between fluoride dose and the number of deaths (P<0.0001). A statistically significant relationship was also found between fluoride dose and fluoride concentration ([F]) in either the whole femur (P<0.0017), on the surface (P<0.0001) or for the ratio periosteal [F]/whole [F] (P<0.0001). However, the [F] on the femur surface was more closely correlated with mortality than that in the whole bone, showing statistically significant differences among the lethal doses and control (P<0.05). The data suggest that the ratio [F] periosteal bone/[F] whole bone, is a biomarker for acute fluoride toxicity.

 

Full free report available at: http://www.fluoride-journal.com/03-36-2/362-095.pdf

Fluoride Vol. 36 No. 2 95-105 2003 Research Report 95

HISTOPATHOLOGICAL INVESTIGATION OF FLUORIDE-INDUCED NEUROTOXICITY IN RABBITS

A Shashi

For Correspondence: Dr Aggarwal Shashi, Department of Zoology, Punjabi University,
Patiala-147002, Punjab, India. E-mail: aggarwalshashi@rediffmail.com

SUMMARY: Brain tissues for neurohistopathological study were obtained at
autopsy from albino rabbits that had been subcutaneously injected for 15
weeks with 0, 5, 10, 20, and 50 mg of sodium fluoride in 1 mL of aqueous solutions/
kg bw/day. Neuropathological changes occurred with loss of the molecular
layer and glial cell layer in the brain tissues of rabbits exposed to the
three higher fluoride doses.
The Purkinje neurones exhibited chromatolysis
and acquired a "ballooned" appearance. Nissl substance showed various degrees
of decrease and even complete loss.
Fragmented particles were retained
in the perinuclear zone. The perikaryon showed vacuolization, and
spheroid bodies were present in the neuroplasm.
These cytoplasmic inclusions
appeared as various sized ovoid bodies or elongated eosinophilic
masses due to which the nucleus was shifted to the periphery. These neurotoxic
changes in the brain suggested that there was a direct action of fluoride
upon the nerve tissue which was responsible for central nervous system
problems such as tremors, seizures, and paralysis indicating brain dysfunction
seen at the two highest doses.


Full free report available at: http://www.fluoride-journal.com/03-36-1/361-030.pdf

Fluoride Vol. 36 No. 1 30-37 2003 Research Report

IN VIVO STUDIES CONCERNING TOXIC EFFECTS OF SODIUM FLUORIDE ON HEPATIC FUNCTION IN RABBITS

A Shashi

For Correspondence: Dr Aggarwal Shashi, Department of Zoology, Punjabi University, Patiala - 147 002, India. E-mail: aggarwalshashi@rediffmail.com

SUMMARY: This study was designed to evaluate the role of fluoride in
inducing hepatotoxicity. The experimental model comprised albino rabbits
treated with 5, 10, 20, and 50 mg NaF/kg-bw/day s.c. for fifteen weeks.
Parameters of hepatotoxicity were proteins, DNA, RNA, free amino acids, and
cholesterol. The data indicate significant reduction in acidic proteins, basic
proteins, total proteins, RNA, and cholesterol in the liver of experimental
animals of both sexes. Hepatic free amino acids were highly elevated in the
exposed rabbits,
suggesting impairment of protein synthesis as well as
reduced incorporation of amino acids into proteins. Hepatic DNA synthesis
increased in rabbits treated with 5 mg NaF/kg-bw/day
and then decreased at
higher doses. These hepatotoxic disturbances induced by fluoride reflect
functional and structural alterations in the liver in experimental fluorosis.


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14666669&dopt=Abstract

Anticancer Res. 2003 Sep-Oct;23(5A):3719-26.

Effect of antioxidants, oxidants, metals and saliva on cytotoxicity induction by sodium fluoride.

Tokunaga T, Morshed SR, Otsuki S, Takayama F, Satoh T, Hashimoto K, Yasui T, Ogawa S, Kanegae H, Yokote Y, Akahane K, Kashimata M, Satoh K, Sakagami H.


Department of Dental Pharmacology, Meikai University School of Dentistry, Sakado, Saitama, Japan.

We have recently found that millimolar concentrations of sodium fluoride (NaF) induced apoptotic cell death, characterized by caspase activation and DNA fragmentation, in tumor cell lines. This finding paved the way to investigating the interaction between NaF and the oral environment. As an initial step, we investigated redox compounds, metals and saliva, which may modify the cytotoxic activity of NaF against a human oral squamous cell carcinoma cell line (HSC-2). The minimum exposure time to NaF required for cytotoxicity induction was 8 hours. Noncytotoxic concentrations of antioxidants (sodium ascorbate, gallic acid, epigallocatechin gallate, chlorogenic acid, curcumin, superoxide dismutase, catalase), oxidants (hydrogen peroxide, sodium hypochlorite), metals (CuCl, CuCl2, FeCl2, FeCl3, CoCl2) or saliva neither protected against, nor enhanced the cytotoxic activity of NaF. Cytotoxic concentrations of these compounds produced somewhat additive, but not synergistic, effects on the cytotoxicity of NaF. ESR analysis demonstrated that NaF did not apparently change the radical intensity of sodium ascorbate and gallic acid, measured under alkaline conditions. During the cell death induction in human promyelocytic leukemia HL-60 cells by NaF, the consumption of glucose rapidly declined, followed by a decline in the consumption of major amino acids. The present study suggests that the cytotoxic activity of NaF is not regulated by the redox mechanism, but rather linked to the rapid decline in glucose consumption at early stage.

PMID: 14666669 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14650182&dopt=Abstract

Wei Sheng Yan Jiu. 2003 Sep;32(5):432-3.

[Effects of fluoride on cell cycle and apoptosis in cultured osteoblasts of rats]

[Article in Chinese]

Zhang Y, Sun G, Jin Y, Wang Y.

School of Public Health, China Medical University, Shenyang 110001, China.

To study the effects of fluoride on cell growth, cell cycle and apoptosis in cultured osteoblasts of rats. The enzymes digesting method was used to isolate the osteoblasts of rats. The activity of the cells was determined by the percents of reduced AlamarBlue. FCM was used to analyze cell cycle and apoptosis. The results showed that the activity of rat osteoblast was not influenced by NaF at 0 to 2 mmol/L concentration after 24 hours incubation. At the concentration of 2 mmol/L, the number of cells at S phase was increased. At the concentration of 4 mmol/L, NaF increased the number of cells at S phase and at the same time, decreased the number of cells at G2/M phase, but the number of the cells at G0/G1 phase kept unchanged. The percent of apoptosis was increased at the concentration of 2 mmol/L. Excessive fluoride could affect the cell activity, retarded cell cycle at S phase and induced apoptosis.

PMID: 14650182 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=14981920

Anticancer Res. 2003 Nov-Dec;23(6C):4729-36.

Effect of antitumor agents on cytotoxicity induction by sodium fluoride.

Morshed SR, Tokunaga T, Otsuki S, Takayama F, Satoh T, Hashimoto K, Yasui T, Okamura M, Shimada J, Kashimata M, Sakagami H.

Meikai Pharmaco-Medical Laboratory (MPL), Meikai University School of Dentistry, Sakado, Saitama, Japan.

We have recently found that sodium fluoride (NaF) induced apoptotic cell death in tumor cell lines. We investigated here whether 6 popular antitumor compounds modify the cytotoxic activity of NaF against human squamous cell carcinoma (HSC-2) and human promyelocytic leukemia (HL-60) cell lines. Cytotoxic concentrations of cisplatin, etoposide, doxorubicin or peplomycin (tentatively termed as Group I compounds), but not methotrexate and 5-FU (tentatively termed as Group II compounds), enhanced the cytotoxic activity of NaF. NaF and Group I compounds induced internucleosomal DNA fragmentation in HL-60 cells, whereas Group II compounds were inactive even in the presence of NaF. Most Group I compounds except doxorubicin (which induced DNA fragmentation less effectively than others) activated caspase 3 more efficiently than Group II compounds. Caspase 8 (involved in non-mitochondrial extrinsic pathway) and caspase 9 (involved in mitochondrial intrinsic pathway) were also activated, but to a much lesser extent. NaF reduced the glucose consumption at early stage, possibly by inhibition of glycolysis, whereas cisplatin and etoposide reduced the glucose consumption at later stage, suggesting that early decline of glucose consumption is rather specific to NaF.

PMID: 14981920 [PubMed - indexed for MEDLINE]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12865044&dopt=Abstract

Environ Res. 2003 Sep;93(1):20-30.

Fluoride-induced disruption of reproductive hormones in men.

Ortiz-Perez D, Rodri;guez-Marti;nez M, Marti;nez F, Borja-Aburto VH, Castelo J, Grimaldo JI, de la Cruz E, Carrizales L, Diaz-Barriga F.

Laboratorio de Toxicologi;a Ambiental, Facultad de Medicina, Universidad Autonoma de San Luis Potosi;, Av. Venustiano Carranza 2405, Col. Lomas Filtros, CP 78210, San Luis Potosi;, Mexico

Fluoride-induced reproductive effects have been reported in experimental models and in humans. However, these effects were found in heavily exposed scenarios. Therefore, in this work our objective was to study reproductive parameters in a population exposed to fluoride at doses of 3-27mg/day (high-fluoride-exposed group-HFEG). Urinary fluoride levels, semen parameters, and reproductive hormones in serum (LH, FSH, estradiol, prolactin, inhibin-B, free and total testosterone) were measured. Results were compared with a group of individuals exposed to fluoride at lower doses: 2-13mg/day (low-fluoride-exposed group-LFEG). A significant increase in FSH (P<0.05) and a reduction of inhibin-B, free testosterone, and prolactin in serum (P<0.05) were noticed in the HFEG. When HFEG was compared to LFEG, a decreased sensitivity was found in the FSH response to inhibin-B (P<0.05). A significant negative partial correlation was observed between urinary fluoride and serum levels of inhibin-B (r=-0.333, P=0.028) in LFEG. Furthermore, a significant partial correlation was observed between a chronic exposure index for fluoride and the serum concentrations of inhibin-B (r=-0.163, P=0.037) in HFEG. No abnormalities were found in the semen parameters studied in the present work, neither in the HFEG, nor in the LFEG. The results obtained indicate that a fluoride exposure of 3-27mg/day induces a subclinical reproductive effect that can be explained by a fluoride-induced toxic effect in both Sertoli cells and gonadotrophs.

PMID: 12865044 [PubMed - as supplied by publisher]


Full free report available at: http://www.fluoride-journal.com/03-36-4/364-241.pdf

Fluoride Vol. 36 No. 4 241-251 2003 - Research Report 241

FLUORIDE AND ADRENAL GLAND FUNCTION IN RABBITS

A Shashi

Department of Zoology, Punjabi University, Patiala - 147 002, India. E-mail : aggarwalshashi@rediffmail.com

SUMMARY: In an investigation of the effect of sodium fluoride (NaF) on adrenal gland function, male and female albino rabbits were administered NaF subcutaneously in 1 mL of double distilled water at dosages of 5, 10, 20, and 50 mg/kg bw/day for 15 weeks. The controls were given 1 mL of double distilled water/kg bw/day for the same period. Slight to large decreases in body weight gain were noted in the NaF exposed animals. Biochemical analysis of the adrenal gland revealed significant (P<0.001) decline in the DNA and RNA content of fluoridated animals of both sexes compared to the control. Accumulation of glycogen indicated reduction in the activities of glycolytic pathway
enzymes. A significant decrease (P<0.001) in acidic, basic, and total proteins in test animals suggested inhibition of protein synthesis by fluoride and increased proteolysis. Significantly (P<0.001) enhanced levels of free amino acids indicated reduced incorporation of amino acids into proteins. Hyperlipidemia and hypertriglyceridemia in the adrenal gland of fluorotic animals reflected
a disturbance of lipoprotein metabolism. In males, phospholipids exhibited significant declines (P<0.001) in groups II and III, but an increase in group IV. In females, the amount of phospholipids was significantly (P<0.001) reduced in groups II, III, and IV. In group V, the level of phospholipids in both sexes returned to the control values. An inhibitory effect of fluoride was also observed on the levels of adrenal free fatty acids and cholesterol.


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15248484

Indian J Exp Biol. 2003 Aug;41(8):857-60.

Lipid peroxidation and antioxidant systems in the blood of young rats subjected to chronic fluoride toxicity.

Shivarajashankara YM, Shivashankara AR, Bhat PG, Rao SH.

Department of Biochemistry, M.R. Medical College, Gulbarga 585105, India. shivrajsym@yahoo.com

Wistar albino rats were exposed to 30 or 100 ppm fluoride in drinking water during their fetal, weanling and post-weaning stages of life up to puberty. Extent of lipid peroxidation and response of the antioxidant systems in red blood cells and plasma to prolonged fluoride exposure were assessed in these rats in comparison to the control rats fed with permissible level (0.5 ppm) of fluoride. Rats treated with 100 ppm fluoride showed enhanced lipid peroxidation as evidenced by elevated malondialdehyde (MDA) levels in red blood cells but, 30 ppm fluoride did not cause any appreciable change in RBC MDA level. 30 ppm fluoride-intake resulted in increased levels of total and reduced glutathione in red blood cells and ascorbic acid in plasma while 100 ppm fluoride resulted in decreases in these levels. The activity of RBC glutathione peroxidase was elevated in both the fluoride-treated groups, more pronounced increase was seen with 100 ppm. Reduced to total glutathione ratio in RBC and uric acid levels in plasma decreased in both the groups. RBC superoxide dismutase activity decreased significantly on high-fluoride treatment. These results suggest that long-term high-fluoride intake at the early developing stages of life enhances oxidative stress in the blood, thereby disturbing the antioxidant defense of rats. Increased oxidative stress could be one of the mediating factors in the pathogenesis of toxic manifestations of fluoride.

PMID: 15248484 [PubMed - in proces


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14502225&dopt=Abstract

EMBO Rep. 2003 Sep 19 [Epub ahead of print].

Spatiotemporal dynamics of the COPI vesicle machinery.

Elsner M, Hashimoto H, Simpson JC, Cassel D, Nilsson T, Weiss M.

Cell Biology and Cell Biophysics Programme, EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.

Assembly of the coat protein I (COPI) vesicle coat is controlled by the small GTPase ADP ribosylation factor 1 (ARF1) and its GTPase-activating protein, ARFGAP1. Here, we investigate the diffusional behaviours of coatomer, the main component of the coat, and also those of ARF1 and ARFGAP1. Using fluorescence-correlation spectroscopy, we found that most ARF1 and ARFGAP1 molecules are highly mobile in the cytosol (diffusion constant D approximately 15 microm(2) s(-1)), whereas coatomer diffuses 5-10 times more slowly than expected (D approximately 1 microm(2) s(-1)). This slow diffusion causes diffusion-limited binding kinetics to Golgi membranes, which, in FRAP (fluorescence recovery after photobleaching) experiments, translates into a twofold slower binding rate. The addition of aluminium fluoride locks coatomer onto Golgi membranes and also decreases the binding kinetics of both ARF1 and ARFGAP1, suggesting that these proteins function in concert to mediate sorting and vesicle formation.

PMID: 14502225 [PubMed - as supplied by publisher]


From Toxline at Toxnet:

Reprod Toxicol 2003 Jul-Aug;17(4):500

EFFECT OF SOME ENVIRONMENTAL CONTAMINANTS ON DIFFERENTIATION IN MICROMASS CULTURE OF RAT EMBRYO LIMB BUDS CELLS.

Minta M, Wlodarczyk B

Department of Pharmacology and Toxicology, National Veterinary Research Institute, Pulawy, Poland.

Out of three in vitro tests validated so far for embryotoxicity prescreening tests, micromass culture of rat limb bud mesenchymal cells (LBC) is one candidate. The prediction model (PM) is based on the value of ID50 (50% inhibition concentration for differentiation) and allows to classify test chemical to one of three class of embryotoxicity: strong (III), weak (II) and non-embryotoxic (I). Confluent monolayer cultures were prepared from rat embryo limb buds, incubated for 5 days, fixed and stained for cell viability (Neutral red) and proteoglycans (Alcian blue). Proliferation and differentiation were determined spectrophotometrically at 540 and 620 nm, respectively. The method was checked in our laboratory with use of reference compounds, i.e. 5-Fluorouracyl (7 concentrations ranged from 15.63 to 1000 ng/ml) and Penicillin G (at 500 ug/ml). Cadmium chloride (CAS No. 10108-64-2), lead acetate (CAS No. 301-04-2) and sodium fluoride (CAS No.7681-49-4) were evaluated in this study. Concentrations used ranged from 0.17-125 ug/ml (Cd), 1.95-125 ug/ml (Pb), and 3.91-250 ug/ml (F). Mean ID50 values (the endpoint value derived from two separate experiments conducted on different days) were as follow: 2.95 ug/ml (Cd), 27.7 ug/ml (Pb), 24.9 ug/ml (F). Cadmium chloride was classified to group III, lead acetate and sodium fluoride -- to group II. Studies are in progress to evaluate more compounds of different teratogenic potential in vivo.


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15552842

Ann Acad Med Stetin. 2003;49:91-109.

[Kinetics of in vitro fluoride uptake by artificial and natural hydroxyapatite]

[Article in Polish]

Trzeciak M.

Ze Studium Doktoranckiego przy Katedrze i Zakladzie Biochemii i Chemii Pomorskiej Akademii Medycznej w Szczecinie, al. Powstancow Wlkp. 72, 70-111 Szczecin.

The nature and kinetics of fluoride uptake by hydroxyapatite under various conditions remain the object of interest. This problem was now investigated with an experimental model reproducing as closely as possible the conditions in vivo. The aim of this work was:
(1) to study the kinetics of fluoride uptake by natural and artificial hydroxyapatite depending on experimental conditions and to determine the reaction rate constants;
(2) to describe the equilibrium of fluoride uptake with adsorption isotherms and develop a best fit mathematical model for the process taking place under various experimental conditions;
(3) to determine and compare the capacity for fluoride uptake by natural and artificial hydroxyapatite depending on experimental conditions.
Attention has focused on the equilibrium and kinetics of the process of fluoride uptake under conditions as similar to those in a living organism as it is possible to reproduce in vitro. Those conditions represented just one of sixteen various experimental setups differing as to process parameters of the experimental system. The equilibria and kinetics of the experimental system were determined basing on measurements of selected parameters. Adsorption isotherms were obtained experimentally and a best fit mathematical model was developed to describe the process. Additionally, maximal capacity for fluoride uptake was calculated, as well as equilibrium constants, adsorption and desorption rate constants for both hydroxyapatite types. The following conclusions were drawn:
1. Fluoride uptake by artificial and natural hydroxyapatite is a biphasic process essentially independent of conditions in the reaction environment adopted in the present work. The first phase is rapid and does not exceed some 15 minutes. The second phase is much slower and takes place over a period of several dozen hours.
2. Fluoride sorption by both hydroxyapatites is essentially a physico-chemical process which can mathematically be best described with Langmuir and Langmuir-Freundlich adsorption isotherms. Under conditions of equilibrium, the adsorbed substance forms a monolayer on the surface of the sorbent.
3. The binding of fluoride by natural hydroxyapatite is stronger than by its artificial counterpart.
4. The stability of fluoroapatite formed during fluoride uptake by natural hydroxyapatite is greater than that of its artificial counterpart.
5. Natural hydroxyapatite has a relatively large capacity for fluoride ions under experimental conditions adopted in the present work. This capacity exceeds that of artificial hydroxyapatite in spite of smaller specific surface of the natural substance.

PMID: 15552842 [PubMed - in process]


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15552840

Ann Acad Med Stetin. 2003;49:63-77.

[The influence of some trace elements on bioaccumulation in tissues and bioenergetic metabolism of the edible snail Helix aspersa maxima as determined by HPLC of purine derivatives]

[Article in Polish]

Rac ME.

Z Katedry i Zakladu Biochemii i Chemii Pomorskiej Akademii Medycznej w Szczecinie, al. Powstancow Wielkopolskich 72, 70-111 Szczecin.

The aim of this work was to determine the bioaccumulation of fluoride and some metals (Cu, Zn, Pb) in tissues of snails under strictly controlled conditions expecting with this approach to verify the hypothesis that snails are suitable for the monitoring of environmental hazards. Additionally, the toxicity of fluorides administered orally on the energy balance of the snail's foot was investigated basing on concentrations of nucleosides, nucleotides and their products measured with high-performance liquid chromatography (HPLC). Two parallel snail cultures were started. The effect of dose on tissue levels of fluoride and metals was studied in the first part of the experiment. The second part served to study the effects of fluoride on energy metabolism of foot muscle (Tab. 1). Quantitation of fluoride and metal levels was done in soft tissues (foot, hepatopancreas) and shells of snails. Qualitative and quantitative analysis of purine compounds was performed in slices of foot. Fluoride concentrations in pulverized shells were measured using an ion-selective electrode. Gas chromatography served to determine fluoride concentrations in soft tissues (hepatopancreas and foot). Concentrations of metals were determined spectrophotometrically. Fluoride and metal content was calculated basing on weight of the pulverized sample. Purines were measured in foot muscle slices with high-performance liquid chromatography (HPLC). Concentrations were adjusted for protein content of sample. Concentrations of the following nucleosides, nucleotides and their products were determined: ATP, ADP, AMP, Ado (adenosine), GTP, GDP, GMP, Guo (guanosine), Hyp (hypoxanthine), IMP, Ino (inosine), Xan (xanthine), Urd (uridine), UA (uric acid), NAD+, and NADP (Fig. 1.). Statistical analysis was done with non-parametric test of Kruskal-Wallis, Mann-Whitney U-test and Spearman Rank Correlation Coefficient.
CONCLUSIONS:
1. Accumulation in the shell was significantly increased at the lowest concentration of fluoride, but levels remained below those in the foot or hepatopancreas. It can be inferred that due to low sensitivity, accumulation of fluoride in soft tissues is not a suitable indicator for biomonitoring purposes. Shells seem to be more suited for this aim.
2. Due to low sensitivity, accumulation of metals in soft tissues is not a suitable indicator for biomonitoring purposes.
3. Fluoride had a statistically significant effect on the energy metabolism in muscle, especially on the content of AMP and GMP (Fig. 3, 4). The content of adenylate derivatives was increased (Fig. 3, 4) and phosphorylation of ADP to ATP was inhibited (Fig. 2, 5).
4. An increase in TAN and AEC with 1330 mg F-/kg seems to result from inhibition by fluoride of energy-consuming processes (Fig. 5).
5. In cases of high levels of fluoride it seems reasonable to measure the content of AMP, GMP, Guo or the value of AEC which appear to serve as universal indicators of depressed metabolic function (Fig. 3, 4, 5, 6).

PMID: 15552840 [PubMed - in process]


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15552839

Ann Acad Med Stetin. 2003;49:45-62.

[The influence of toxic doses of fluorine on the expression of collagen genes and synthesis of some collagen proteins in rat skin]

[Article in Polish]

Olszowski T.

Ze Studium Doktoranckiego przy Katedrze i Zakladzie Biochemii i Chemii Pomorskiej Akademii Medycznej w Szczecinie, al. Powstancow Wlkp. 72, 70-111 Szczecin.

The results of studies carried out over the last few decades indicate a significant involvement of fluoride in connective tissue metabolism. Unfortunately, opinions concerning this issue vary and sometimes are conflicting. Collagen constitutes the main component of the extracellular matrix. Biosynthesis of collagen is a complex, multistage process. Each step in collagen biosynthesis may be affected by exogenous factors. The purpose of the present study was to evaluate the effects of toxic doses of fluoride in drinking water on:
1. The level of COL1A1 gene expression in rat skin;
2. Concentrations of acid-soluble, pepsin-soluble and total collagen isolated from rat skin;
3. Ratio of pepsin-soluble to acid-soluble collagen concentrations;
4. Proportions of alpha2(I)/alpha1(I) and beta/alpha1(I) collagen chains in extracts ofpepsin-soluble collagen. An attempt was made to determine whether fluoride effects are gender-dependent.
The experiment was performed in 108 Wistar rats (males and females). Rats were given 60 mg sodium fluoride/dm3 in drinking during 1, 3 or 6 months. Subsequently, animals were sacrificed and blood, femoral bones and fragments of abdominal skin were taken for analysis. Methods used in the study included potentiometry with F- ion-selective electrode, RT-PCR assay, calorimetry, and SDS-PAGE electrophoresis. The results led to the following conclusions:
1. COL1A1 gene expression in the skin of male rats receiving 60 mg NaF/dm3 in drinking water was significantly reduced after 6 months exposure.
2. Fluoride at doses used in the present study basically does not exert an effect on the concentration of each collagen form in rat skin, ratio of pepsin-soluble to acid-soluble collagen concentrations, and relative proportions of some collagen chains in the pepsin-soluble collagen extract.
3. Male rats were more sensitive to fluoride action in the present study as compared with females.
4. Further research on fluoride penetration to the skin in experimental animals is needed in order to elucidate the relatively low toxicity of fluoride in this tissue.

PMID: 15552839 [PubMed - in process]


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15266917

Indian J Exp Biol. 2003 Jun;41(6):652-4.

Trace element concentration in various tissues following fluoride administration to female mice.

Bhatnagar M, Rao P, Bhatnagar C, Bhatnagar R.

Department of Zoology, University College of Science, M.L.S. University, Udaipur 313 001, India. mbhatnagar@yahoo.com

Brain, liver, kidney and muscles demonstrate significant changes in essential trace element (Cu, Zn, Mn and Fe) level in adult female mice given 30, 60 and 120 ppm sodium fluoride (NaF) in drinking water. These changes involve excess removal or accumulation of these trace elements in respective tissues. Changes observed were dose dependent and significant at 120 ppm NaF concentration in drinking water.

PMID: 15266917 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12944586&dopt=Abstract

Toxicol Sci. 2003 Nov;76(1):131-7. Epub 2003 Aug 27.

Toxicological and Structural Features of Organophosphorus and Organosulfur Cannabinoid CB1 Receptor Ligands.

Segall Y, Quistad GB, Sparks SE, Nomura DK, Casida JE.

Environmental Chemistry and Toxicology Laboratory, Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720-3112.

Potent cannabinoid CB1 receptor ligands include anandamide [N-(2-hydroxyethyl)arachidonamide], Delta(9)-tetrahydrocannabinol and [(3)H]CP 55,940 at the agonist site and selected organophosphorus esters (including some pesticides) and organosulfur compounds at a proposed closely-coupled "nucleophilic" site. This study considers the toxicological and structural features of alkylfluorophosphonates, benzodioxaphosphorin oxides, alkanesulfonyl fluorides and analogs acting at the nucleophilic site. Binding at the agonist site, using [(3)H]CP 55,940 in assays with mouse brain membranes, is inhibited by O-isopropyl dodecylfluorophosphonate (compound 2), dodecanesulfonyl fluoride (compound 14) and dodecylbenzodioxaphosphorin oxide with IC50 values of 2-11 nM. Compounds 2 and 14 are also effective in vivo, with 84% inhibition of mouse brain CB1 binding 4 h after intraperitoneal dosage at 30 mg/kg. Compound 14-inhibited CB1 in mouse brain requires about 3-4 days for recovery of 50% activity, suggesting covalent derivatization. Delayed toxicity (mortality in 0.3-5 days) from compounds 2, 14 and octanesulfonyl fluoride (18) is more closely associated with in vivo inhibition of brain neuropathy target esterase - lysophospholipase (NTE-LysoPLA) than with that of CB1 or acetylcholinesterase. NTE-LysoPLA inhibited by sulfonyl fluorides 14 and 18 cannot "age," a proposed requirement for NTE phosphorylated by organophosphorus delayed neurotoxicants. Several octane- and dodecanesulfonamides with N-(2-hydroxyethyl) and other substituents based on anandamide give depressed mobility and recumbent posture in mice, but the effects do not correlate with potency for CB1 inhibition in vitro. Specific toxicological responses are not clearly associated with organophosphorus- or organosulfur-induced inhibition of the proposed CB1 nucleophilic site in mouse brain. On the other hand, the most potent CB1 inhibitors examined here are also NTE-LysoPLA inhibitors and cause delayed toxicity in mice.

PMID: 12944586 [PubMed - as supplied by publisher]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12951114&dopt=Abstract

Bioorg Med Chem Lett. 2003 Oct 16;13(19):3301-3.

Arachidonylsulfonyl derivatives as cannabinoid CB1 receptor and fatty acid amide hydrolase inhibitors.

Segall Y, Quistad GB, Nomura DK, Casida JE.

Environmental Chemistry and Toxicology Laboratory, Department of Environmental Science, Policy and Management, University of California, 94720-3112, Berkeley, CA, USA

Arachidonylsulfonyl fluoride (3), reported here for the first time, is similar in potency to its known methyl arachidonylfluorophosphonate (2) analogue as an inhibitor of mouse brain fatty acid amide hydrolase activity (IC(50) 0.1 nM) and cannabinoid CB1 agonist [3H]CP 55,940 binding (IC(50) 304-530 nM). Interestingly, 3 is much more selective than 2 as an inhibitor for fatty acid amide hydrolase relative to acetylcholinesterase, butyrylcholinesterase and neuropathy target esterase. N-(2-Hydroxyethyl)arachidonylsulfonamide (4) is at least 2500-fold less potent than N-(2-hydroxyethyl)arachidonamide (anandamide) (1) at the CB1 agonist site.

PMID: 12951114 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12723891&dopt=Abstract

Hum Exp Toxicol 2003 Mar;22(3):111-23

Fluoride-induced apoptosis in human epithelial lung cells (A549 cells): role of different G protein-linked signal systems.

Refsnes M, Schwarze PE, Holme JA, Lag M.

Division of Environmental Medicine, Norwegian Institute of Public Health, Geitmyrsvn. 75, PO Box 4404 Nydalen, N-0403 Oslo, Norway. magne.refsnes@fhi.no

In the present study, possible mechanisms involved in fluoride-induced apoptosis in a human epithelial lung cell line (A549) were examined. Sodium fluoride (NaF) induced apoptosis in the A549 cells, with a maximum at 5-7.5 mM after 20 hours of exposure. The number of cells with plasma membrane damage (PI-positive cells) increased moderately up to 5 mM, but markedly at 7.5 mM. Deferoxamine (an Al3+ chelator) almost completely prevented these NaF-induced responses, which may suggest a role for G protein activation. The apoptotic effect was partially reduced by the PKA inhibitor H89. NaF induced a weak but sustained increase in PKC activity, whereas the PKC activator TPA induced a transient effect. TPA, which enhanced the NaF-induced PKC activity, was not apoptotic when added alone, but facilitated the NaF-induced apoptosis and the increase in PI-positive cells. PKC downregulation induced by TPA pretreatment almost completely prevented the NaF-induced apoptosis and the increase in PI-positive cells. Pretreatment with the PKC inhibitor GF109203X, which abolished the PKC activity after 3 hours, enhanced the NaF-induced apoptosis. KN93 (a CaM kinase II inhibitor) and W7 (a calmodulin inhibitor) seem to reduce the apoptotic effect of NaF, whereas BAPTA-AM (a Ca2+ chelator) was without effect. The tyrosine kinase inhibitor genistein also markedly reduced the NaF-induced apoptosis, whereas the PI-3 kinase inhibitor wortmannin augmented the response. In conclusion, the present results suggest that NaF induces an apoptotic effect and an increase in PI-positive A549 cells via similar mechanisms, involving PKC, PKA, tyrosine kinase and Ca2+-linked enzymes, whereas PI-3 kinase seems to exert a counteracting effect.

PMID: 12723891 [PubMed - in process]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12898089&dopt=Abstract
Exp Brain Res. 2003 Jul 24 [Epub ahead of print].

GTP(gammaS) increases Na(v)1.8 current in small-diameter dorsal root ganglia neurons.
 
Saab CY, Cummins TR, Waxman SG.
 
Department of Neurology and PVA/Eastern Paralyzed Veterans Association Neuroscience Research Center, Yale Medical School, CT 06510, New Haven, USA.
 
Tetrodotoxin-resistant (TTX-R) sodium current in small-size dorsal root ganglia (DRG) neurons is upregulated by prostaglandin E(2) and serotonin through a protein kinase A (PKA)/protein kinase (PKC) pathway, suggesting G protein modulation of one or more TTX-R channels in these neurons. Recently, GTP(gammaS), a hydrolysis-resistant analogue of GTP, was shown to increase the persistent current produced by the TTX-R Na(v)1.9. In this study, we investigated the modulation of another TTX-R channel, Na(v)1.8, by GTP(gammaS) in small-diameter DRG neurons from rats using whole-cell voltage clamp recordings. Because it has been suggested that fluoride, often used in intracellular recording solutions, may bind to trace amounts of aluminum and activate G proteins, we recorded Na(v)1.8 currents with and without intracellular fluoride, and with the addition of deferoxamine, an aluminum chelator, to prevent fluoride-aluminum binding. Our results show that GTP(gammaS) (100 micro M) caused a significant increase in Na(v)1.8 current (67%) with a chloride-based intracellular solution. Although the inclusion of fluoride instead of chloride in the pipette solution increased the Na(v)1.8 current by 177%, GTP(gammaS) further increased Na(v)1.8 current by 67% under these conditions. While the effect of GTP(gammaS) was prevented by pretreatment with H7 (100 micro M), a non-selective PKA/PKC inhibitor, the fluoride-induced increase in Na(v)1.8 current was not sensitive to H7 (100 micro M), or to inclusion of deferoxamine (1 mM) in the intracellular solution. We conclude that G protein activation by GTP(gammaS) increases Na(v)1.8 current through a PKA/PKC mechanism and that addition of fluoride to the pipette solution further enhances the current, but is not a confounding variable in the study of Na(v)1.8 channel modulation by G proteins independent of a PKA/PKC pathway or binding to aluminum.
 
PMID: 12898089 [PubMed - as supplied by publisher]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12869498&dopt=Abstract
 
Blood. 2003 Jul 17 [Epub ahead of print].
 
Generation of an erythrocyte vesicle transport system by Plasmodium falciparum malaria parasites.
 
Taraschi TF, O'Donnell M, Martinez S, Schneider T, Trelka D, Fowler VM, Tilley L, Moriyama Y.
 
The asexual maturation of Plasmodium falciparum is accompanied by the transport of parasite encoded proteins to the erythrocyte plasma membrane. Activation of G-proteins by treatment with aluminum fluoride produced an accumulation within the erythrocyte cytosol of vesicles coated with Plasmodium homologues of COPII and N-ethylmaleimide-sensitive factor, proteins involved in intracellular transport between the Golgi apparatus and the endoplasmic reticulum. These vesicles contain malarial proteins that appear on the erythrocyte plasma membrane, as well as actin and myosin. It is proposed that the parasite adapted a process well established for intracellular transport to mediate the extracellular movement of its proteins through the erythrocyte cytosol to the surface membrane.
 
PMID: 12869498 [PubMed - as supplied by publisher]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12764073&dopt=Abstract

Crit Rev Oral Biol Med 2003;14(2):100-14

The biochemistry and physiology of metallic fluoride: action, mechanism, and implications.

Li L.

Faculty of Dentistry, University of Manitoba, 780 Bannatyne Avenue, Winnipeg R3E 0W2, MB, Canada; umlil@cc.umanitoba.ca

Fluoride is a well-known G protein activator. Activation of heterotrimeric GTP-binding proteins by fluoride requires trace amounts of Al3+ or Be2+ ions. AlFx mimics a gamma-phosphate at its transition state in a Galpha protein and is therefore able to inhibit its GTPase activity. AlFx also forms complexes with small GTP-binding proteins in the presence of their GTPase-activating proteins (GAP). As phosphate analogs, AlFx or BeFx affect the activity of a variety of phosphoryl transfer enzymes. Most of these enzymes are fundamentally important in cell signal transduction or energy metabolism. Al3+ and F- tend to form stable complexes in aqueous solution. The exact structure and concentration of AlFx depend on the pH and the amount of F- and Al3+ in the solution. Humans are exposed to both F and Al. It is possible that Al-F complexes may be formed in vivo, or formed in vitro prior to their intake by humans. Al-F complexes may play physiological or pathological roles in bone biology, fluorosis, neurotoxicity, and oral diseases such as dental caries and periodontal disease. The aim of this review is to discuss the basic chemical, biochemical, and toxicological properties of metallic fluoride, to explore its potential physiological and clinical implications.

PMID: 12764073 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12763087&dopt=Abstract

Neuroscience 2003;119(1):265-75

Excitatory gaba input directly drives seizure-like rhythmic synchronization in mature hippocampal CA1 pyramidal cells.

Fujiwara-Tsukamoto Y, Isomura Y, Nambu A, Takada M.

Department of System Neuroscience, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, 183-8526, Tokyo, Japan

GABA, which generally mediates inhibitory synaptic transmissions, occasionally acts as an excitatory transmitter through intense GABA(A) receptor activation even in adult animals. The excitatory effect results from alterations in the gradients of chloride, bicarbonate, and potassium ions, but its functional role still remains a mystery. Here we show that such GABAergic excitation participates in the expression of seizure-like rhythmic synchronization (afterdischarge) in the mature hippocampal CA1 region. Seizure-like afterdischarge was induced by high-frequency synaptic stimulation in the rat hippocampal CA1-isolated slice preparations. The hippocampal afterdischarge was completely blocked by selective antagonists of ionotropic glutamate receptors or of GABA(A) receptor, and also by gap-junction inhibitors. In the CA1 pyramidal cells, oscillatory depolarizing responses during the afterdischarge were largely dependent on chloride conductance, and their reversal potentials (average -38 mV) were very close to those of exogenously applied GABAergic responses. Moreover, intracellular loading of the GABA(A) receptor blocker fluoride abolished the oscillatory responses in the pyramidal cells. Finally, the GABAergic excitation-driven afterdischarge has not been inducible until the second postnatal week. Thus, excitatory GABAergic transmission seems to play an active functional role in the generation of adult hippocampal after discharge, in cooperation with glutamatergic transmissions and possible gap junctional communications. Our findings may elucidate the cellular mechanism of neuronal synchronization during seizure activity in temporal lobe epilepsy.

PMID: 12763087 [PubMed - in process]


Full free report available at: http://www.fluoride-journal.com/03-36-3/363-189.pdf

Fluoride Vol. 36 No. 3 189-197 2003 Research Report 189

EFFECT OF VITAMIN D ON CHRONIC BEHAVIORAL AND DENTAL TOXICITIES OF SODIUM FLUORIDE IN RATS
 
Perumal Ekambaram (a), Vanaja Paul (b)
 
For Correspondence: Vanaja Paul, F–1, Varalakshmi Castle, 3, Akbarabad II Street,
Kodambakkam, Chennai – 600 024 (Madras), India.
(a) Lecturer in Zoology, Bharathiar University,
Coimbatore – 641 046, India. E-mail: ekas3001@rediffmail.com
(b) Professor of Pharmacology
(Retd), University of Madras, Chennai, India.
 
SUMMARY: Adult female Wistar rats were treated daily for 60 days with sodium fluoride (500 ppm NaF = 226 ppm fluoride ion) in drinking water, alone or in combination with vitamin D (200 IU/kg by oral intubation). Throughout the period, food intake was measured daily. Body weight gain, exploratory motor activity (EMA) rota-rod motor coordination, dental structure, brain acetylcho-linesterase (AchE) activity, and serum fluoride and serum calcium concentration were determined 24 hr after the last treatment. Serum fluoride concentration increased markedly in the NaF-treated animals and was accompanied by decreased food intake, reduced body weight gain, impairment of EMA and motor coordination, dental lesions, inhibition of brain AchE activity, and hy-pocalcemia. Administration of vitamin D along with NaF prevented hypocalcemia. However, the toxic action fluoride on motor coordination, brain AchE activity, and the teeth was not prevented in these animals, probably because vitamin D is not able to decrease the level of fluoride in the serum. Therefore, vitamin D has only limited value as a protective dietary factor against chronic
toxic effects of fluoride.

Full free report available at: http://www.fluoride-journal.com/03-36-3/363-152.pdf
Fluoride Vol. 36 No. 3 152-156 2003
 
CHANGES IN ERYTHROCYTE PARAMETERS OF FLUOROTIC SHEEP
 
F Yur (a), F Belge (b), N Mert (c), I² Yörük (d)
 
(a) For Correspondence: Fatmagül Yur, Department of Biochemistry, Faculty of Veterinary Medicine, Yuzuncu Yil University,Van 65080,Turkey; E-mail: fatmagulyur@hotmail.com;
(b) Dept. of Physiology, Faculty of Veterinary Medicine;
(c) Dept. of Biochemistry, Faculty of
Veterinary Medicine;
(d) Dept. of Biochemistry, Faculty of Education.
SUMMARY: The aim of this study was to investigate changes in oxidative stress parameters of erythrocytes in twenty 3–4 year-old fluorotic sheep as compared to twenty controls. Malondialdehyde (MDA) levels (mean ± SD) were significantly elevated in erthyrocytes of the fluorotic sheep (2.51 ± 0.16
nmol/mL) in comparison to the control sheep (1.32 ± 0.13 nmol/mL). Erythrocyte Na + -K + adenosine-5’-triphosphatase (Na + -K + ATPase) activity in the fluorotic sheep (0.003 ± 0.0005 µµµµmol Pi/mg protein/h) was significantly lower than in the controls (0.005 ± 0.0005 µµµµmol Pi/mg protein/h), as was the activity of glucose-6-phosphate dehydrogenase (G6PD) (510 ± 23.30 mU/g Hb) compared to the controls (1418 ± 85.40 mU/g Hb). The results are explained by fluoride-induced oxidative stress reflected in elevated erythrocyte MDA levels that cause decreased enzyme activity of Na + -K + ATPase and G6PD by affecting membrane structure.

Full free report available at: http://www.fluoride-journal.com/03-36-3/363-170.pdf
Fluoride Vol. 36 No. 3 170-176 2003 Research Report
 
EFFECTS OF TAMOXIFEN AND NAF ON SERUM AND HEPATIC ENZYMES
 
Boguslaw Czerny(a), Zygmunt Juzyszyn, Zofia Mysliwiec, Anna Put

For Correspondence: Dr Boguslaw Czerny, Department of Pharmacokinetics and
Therapeutic Drug Monitoring, Pomeranian Academy of Medicine, al. Powstanców Wlkp
72, 70-111 Szczecin, Poland. E-mail: zjuzyszyn@wp.pl

 
SUMMARY: Male Wistar rats were given tamoxifen (2 or 4 mg/kg bw/day) and sodium fluoride (20 mg/kg bw/day), five days a week, for six months. Significant adverse changes were observed in the activities of the serum enzymes alanine and aspartate aminotransferase (AlAT and AspAT) and gamma-glutamyl
transpeptidase (y-GT), the liver content of cytochrome P-450, and the activity of hepatic NADPH-cytochrome c reductase.

Full free report available at: http://www.fluoride-journal.com/03-36-1/361-025.pdf

Fluoride Vol. 36 No. 1 25-29 2003 Research Report 25

OXIDATIVE STRESS FROM FLUORIDE-INDUCED HEPATOTOXICITY IN RATS

Xiao-ying Guo (a), Gui-fan Sun, Ying-chun Sun

(a) For Correspondence: Department of Occupational Hygiene, School of Public Health, China Medical University, Shenyang, China, 110001. E-mail: guoxiaoying@yahoo.com

SUMMARY: The role of oxidative stress in fluoride hepatotoxicity was
investigated. Three groups of eight 4-week-old Wistar rats were given 50, 100,
and 150 mg NaF/L in their drinking water for three months. Serum glutamate
pyruvate transaminase (SGPT) and serum glutamate oxalate transaminase
(SGOT) activities increased significantly, suggesting hepatic damage.

Alterations of the oxidative and the antioxidant system in the liver were
confirmed by the significant increase in malondialdehyde (MDA) together with
enhanced superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)
activities in that organ. Oxidative damage from oxidative stress therefore
appears to be an important pathway for fluoride-induced hepatotoxicity.


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12724618&dopt=Abstract

Pharmacogenetics 2003 May;13(5):265-270

Frequency of butyrylcholinesterase gene mutations in individuals with abnormal inhibition numbers: an Italian-population study.

Lando G, Mosca A, Bonora R, Azzario F, Penco S, Marocchi A, Panteghini M, Patrosso MC.

aLaboratorio Analisi Chimico Cliniche Patologia Clinica, Ospedale Niguarda Ca' Granda, Milano, Italy, bDipartimento di Scienze e Tecnologie Biomediche, Universita degli Studi, Milano, Italy, cLaboratorio Analisi Chimico Cliniche 1, Azienda Ospedaliera 'Spedali Civili', Brescia, Italy and dServizio di Immunoematologia Trasfusionale, AVIS, Ospedale Niguarda Ca' Granda, Milano, Italy.

OBJECTIVES More than 30 genetic variants of serum cholinesterase (butyrylcholinesterase, BChE) have been described. Some of them (the atypical and the fluoride-resistant variants) are well known because carriers are prone to develop prolonged apnea following the administration of the muscle relaxant succinylcholine. Genotype characterization is therefore important in order to prevent such episodes. Genetic studies have so far focused on selected individuals or families rather than on the random population.
METHODS From a large group of healthy blood donors (n = 2609), we selected all the 58 individuals with low serum cholinesterase activity: among them 28 subjects had abnormal dibucaine and fluoride inhibition numbers. Twenty-five mutations in the coding region of the human cholinesterase gene were analyzed.
RESULTS All individuals with abnormal inhibition numbers were homozygotes or double heterozygotes in several mutations. Asp70Gly (Atypical variant) and Ala539Thr (K variant) were the most frequently observed amino acid substitutions. The majority of subjects with low BChE activity but normal dibucaine and fluoride number presented only the K form. We analyzed 106 randomly chosen subjects for K and atypical variants. Carriers of these alleles were at risk of low BChE activity (OR = 9.55, 95%CI, 5.61-16.26 and OR = 30.33, 95%CI, 7.05-130.52 respectively).
CONCLUSIONS Data obtained from this study help to better define the etiology of low BChE activity and the role of the rather common K allele. It is the first time that such a large population has been screened for so many mutations. BChE is also implicated in detoxifying cocaine; therefore genetic analysis could be useful in cases of cocaine toxicity in Italian subjects.

PMID: 12724618 [PubMed - as supplied by publisher]


Free full text article at http://www.jbc.org/cgi/reprint/M302130200v1.pdf

J Biol Chem 2003 Apr 3; [epub ahead of print]

Atypical effect of salts on the thermodynamic stability of human prion protein

Apetri AC, Surewicz WK.

Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106.

Prion diseases are associated with the conversion of cellular prion protein, PrP(C), into a misfolded oligomeric form, PrP(Sc). Previous studies indicate that salts promote conformational conversion of the recombinant prion protein into a PrP(Sc)-like form. To gain insight into the mechanism of this effect, here we have studied the influence of a number of salts (sodium sulfate, sodium fluoride, sodium acetate and sodium chloride) on the thermodynamic stability of the recombinant human prion protein. Chemical unfolding studies in urea show that at low concentrations (below approximately 50 mM), all salts tested significantly reduce the thermodynamic stability of the protein. This highly unusual response to salts was observed for both the full-length prion protein as well as the N-truncated fragments huPrP90-231 and huPrP122-231. At higher salt concentrations, the destabilizing effect was gradually reversed, and salts behaved according to their ranking in the Hofmeister series. The present data indicate that electrostatic interactions play an unusually important role in the stability of the prion protein. The abnormal effect of salts is likely due to the ion-induced destabilization of salt bridges (Asp144-Arg148 and/or Asp147-Arg151) in the extremely hydrophilic helix 1. Contrary to previous suggestions, this effect is not due to the interaction of ions with the glycine-rich flexible N-terminal region of the prion protein. The results of this study suggest that ionic species present in the cellular environment may control the PrP(C) to PrP(Sc) conversion by modulating the thermodynamic stability of the native PrP(C) isoform.

PMID: 12676939 [PubMed - as supplied by publisher]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12504354&dopt=Abstract

Toxicology 2003 Feb 1;183(1-3):235-42

Selective decreases of nicotinic acetylcholine receptors in PC12 cells exposed to fluoride.

Chen J, Shan KR, Long YG, Wang YN, Nordberg A, Guan ZZ.

Department of Pathology, Guiyang Medical College, 550004, Guizhou, Guiyang, PR China

In an attempt to elucidate the mechanism by which excessive fluoride damages the central nervous system, the effects of exposure of PC12 cells to different concentrations of fluoride for 48 h on nicotinic acetylcholine receptors (nAChRs) were characterized here. Significant reductions in the number of binding sites for both [3H]epibatidine and [125I]alpha-bungarotoxin, as well as a significant decrease in the B(max) value for the high-affinity of epibatidine binding site were observed in PC12 cells subjected to high levels of fluoride. On the protein level, the alpha3 and alpha7 subunits of nAChRs were also significantly decreased in the cells exposed to high concentrations of fluoride. In contrast, such exposure had no significant effect on the level of the beta2 subunit. These findings suggest that selective decreases in the number of nAChRs may play an important role in the mechanism(s) by which fluoride causes dysfunction of the central nervous system.

PMID: 12504354 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12571456&dopt=Abstract

J Cereb Blood Flow Metab 2003 Feb;23(2):249-260

Brain Uptake of the Acid Metabolites of F-18-Labeled WAY 100635 Analogs.

Carson RE, Wu Y, Lang L, Ma Y, Der MG, Herscovitch P, Eckelman WC.

The 5-HT ligands [ F]FPWAY and [ F]FCWAY are metabolized to [ F]fluorobenzoic acid (FB) and [ F]fluorocyclohexanecarboxylic acid (FC), respectively. To quantify the penetration of these acids into the brain, dynamic positron emission tomography studies were performed in rhesus monkeys with [ F]FB and [ F]FC. High-performance liquid chromatography analysis of arterial blood samples showed no metabolites for [ F]FB, whereas [ F]FC was rapidly metabolized to [ F]fluoride. A model with one tissue compartment and vascular radioactivity was used to analyze gray matter time-activity curves. For [ F]FC, an additional term was added to account for [ F]fluoride skull spillover into the brain; this term accounted for 70% to 90% of the measured radioactivity concentration at 90 minutes. For [ F]FB, mean gray matter parameters were as follows:, 10 +/- 3 &mgr;L. min. mL; distribution volume, 0.052 +/- 0.006 (mL/mL). For [ F]FC, the values were as follows:, 15 +/- 4 &mgr;L. min. mL;, 0.29 +/- 0.06 mL/mL. The values were consistent with a physiologic model that included brain-to-blood pH difference and the plasma free fraction of the acid. Simulations based on [ F]FCWAY human data showed that [ F]FC uptake produces significant biases in estimates in regions with low specific binding. These results can be used to correct the tissue [ F]FCWAY time-activity data for brain uptake of [ F]FC using the measured [ F]FC input function.(1A) (1) (1)

PMID: 12571456 [PubMed - as supplied by publisher]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12535605&dopt=Abstract

Biochim Biophys Acta 2003 Jan 31;1645(1):6-14

Change and stabilization of the amyloid-beta(1-40) secondary structure by fluorocompounds.

Vieira EP, Hermel H, Mohwald H.

Max-Planck-Institute for Colloids and Interfaces, Campus Golm, D-14476, Potsdam, Germany

The misfolding of the amyloid peptide, which is the result of a well-known alpha-to-beta transition, causes neurodegenerative disorder. Fluorinated alcohols have been described in the literature as potent solvents which can refold the beta-conformation. The present studies demonstrate the effectiveness of differently fluorinated alcohols for the beta-to-alpha refolding process on fibrillar aggregated amyloid beta(1-40). The regenerated helical structure is shown to be maintained in the absence of the fluoroalcohols, a behaviour which was found to contrast with immunoglobulin. We interpret this difference on the basis of the hydrophilic/hydrophobic domains in the amyloid sequence and present some speculations regarding the free-energy levels of the folded states of both proteins. The effect of the -CF(3) group on the observed conformational changes is interpreted as a result of alterations of the hydration shell of the peptides. Moreover, based on the results achieved with fluoroalcohols, we have used novel fluorinated amphiphiles possessing blood-compatibility properties and studied their effect on amyloid beta(1-40). First results point in the direction of a beta-to-alpha transition. Therefore, the use of fluorine groups in the development of new drugs is considered a new possibility requiring further investigation for the prevention of amyloidosis.

PMID: 12535605 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12536050&dopt=Abstract

Neurosci Lett 2003 Feb 13;337(3):167-9

Inflammation induced increase of fluoride resistant acid phosphatase (FRAP) activity in the spinal dorsal horn in rats.

Glykys J, Guadama M, Marcano L, Ochoa E, Eblen-Zajjur A.

Departamento de Ciencias Fisiologicas, Facultad de Ciencias de la Salud, Universidad de Carabobo, P.O. Box 3798, El Trigal, Valencia, Venezuela.

Fluoride-resistant acid phosphatase (FRAP) has been suggested as an enzymatic marker for nociceptive primary afferent terminals in the spinal dorsal horn, however there has not been demonstrated a direct functional relation between FRAP activity and an increased nociceptive transmission. For this purpose, we quantitated FRAP activity in the spinal dorsal horn of the rat in a heat-induced cutaneous inflammatory model. Male Sprague-Dawley rats anaesthetised with thiopental were separated in two groups where the left hindpaw was submerged during 60 s either in water at room temperature (control group) or in water at 60 degrees C (inflammation group) which induce in this group a progressive hindpaw inflammation. After 8 h, the lumbar enlargement of the spinal cord was extracted, cut in slices and 1 mm micropunch fragments were obtained from the right and left dorsal horn. The activity of FRAP was determined using the Gomori colorimetric method and corrected by the protein concentrations. FRAP activity in the left dorsal horn was statistically higher than right dorsal horn in the inflammation group (3.05+/-0.54 versus 1.91+/-0.23 u/g per l; P<0.05). Also, FRAP activity from the left dorsal horn of the control and inflammation groups show a significant increase in the last group (3.05+/-0.54 versus 2.17+/-0.23 u/g per l; P<0.05). This results demonstrate that FRAP is not only an enzymatic marker for neuronal and fibre integrity of nociceptive primary afferents but also it is associated to the nociceptive afferent activation.

PMID: 12536050 [PubMed - indexed for MEDLINE]

Note from FAN:
Definition of Dorsal Horn: At the back of spinal cord the central grey matter forms two arms, each called a Dorsal Horn. The dorsal horns contain the cell bodies of sensory neurons. Two arms located at the front of the spinal cord, central grey matter are called ventral horns. They contain the cell bodies of motor neurons.
Ref: http://psych.athabascau.ca/html/Psych402/Biotutorials/15/dorsal_horn.shtml
 

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12644895&dopt=Abstract

Naunyn Schmiedebergs Arch Pharmacol 2003 Mar;367(3):237-44

Anandamide metabolism by fatty acid amide hydrolase in intact C6 glioma cells. Increased sensitivity to inhibition by ibuprofen and flurbiprofen upon reduction of extra- but not intracellular pH.

Holt S, Fowler CJ.

Department of Pharmacology and Clinical Neuroscience, Umea University, 901 87, Umea, Sweden, Sandra.Holt@pharm.umu.se

The metabolism of anandamide by fatty acid amidohydrolase (FAAH) at different intra- and extracellular pH values has been investigated in intact C6 rat glioma cells. The cellular uptake of anandamide at 37 degrees C was found to decrease by 28% when the extracellular pH (pH(e)) was reduced from pH 7.4 to pH 6.2. In contrast, a selective decrease in intracellular pH (pH(i)), accomplished by acidifying the cells followed by incubation in sodium-free buffer at pH 7.4, did not affect the uptake. Anandamide uptake was inhibited by (R)-ibuprofen, with pI(50) values of 3.05+/-0.57, 3.66+/-0.23 and 3.94+/-0.88 at pH(e) values of 7.4, 6.8 and 6.2, respectively. In the presence of phenylmethylsulfonyl fluoride, however, (R)-ibuprofen failed to inhibit the uptake of anandamide. A reduction in pH(e) from 7.4 to 6.2 produced a 17% reduction in the FAAH-catalyzed metabolism of anandamide in the intact C6 cells. However, an increased sensitivity of FAAH activity to inhibition by (R)-ibuprofen as well as (R,S)-flurbiprofen and (S)-flurbiprofen was seen at a lower pH(e). For (R)-ibuprofen, pI(50) values of 3.57+/-0.08, 4.04+/-0.05 and 4.59+/-0.04 were found at pH(e) values of 7.4, 6.8 and 6.2, respectively. For (R,S)- and (S)-flurbiprofen, the pI(50) values at pH(e) 7.4 were 4.02+/-0.05 and 4.13+/-0.18, respectively at a pH(e) of 7.4, and 4.81+/-0.11 and 4.84+/-0.10, respectively, at a pH(e) of 6.2. In contrast, intracellular acidification did not affect either the rate of anandamide metabolism or its inhibition by (R)-ibuprofen or (S)-flurbiprofen. It is concluded that a reduction of extracellular pH produces an enhanced accumulation of the acidic NSAIDs ibuprofen and flurbiprofen into C6 glioma cells and thereby an inhibition of anandamide metabolism.

PMID: 12644895 [PubMed - in process]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12641435&dopt=Abstract

Chem Res Toxicol 2003 Mar;16(3):350-6

Major intermediates in organophosphate synthesis (PCl3, POCl3, PSCl3, and their diethyl esters) are anticholinesterase agents directly or on activation.

Segall Y, Quistad GB, Sparks SE, Casida JE.

Environmental Chemistry and Toxicology Laboratory, Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720-3112, USA.

Three phosphotrichlorides [phosphorus trichloride (PCl(3)), phosphorus oxychloride (POCl(3)), and thiophosphoryl chloride (PSCl(3))] with an annual U.S. production of >500,000,000 pounds and their diethyl esters are intermediates in the production of organophosphorus pesticides, plastics, flame retardants, and hydraulic fluids. They are classified as highly toxic to mammals based on acute oral and inhalation data with rats. This study considers their mechanisms of toxicity. PCl(3) and POCl(3) inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) from several species with in vitro IC(50) values of 5-36 and 88-1200 microM, respectively; PSCl(3) is a less potent inhibitor. These phosphotrichlorides have high vapor toxicity to houseflies with in vivo inhibition of brain AChE activity correlating with mortality. PCl(3) and POCl(3) produce cholinergic poisoning signs on ip administration to mice, and all three phosphotrichlorides give marked in vivo inhibition of serum BChE but not brain AChE activity. PCl(3) is a direct acting AChE inhibitor. Our earlier proposed activation of POCl(3) is confirmed here by preparing pure Cl(2)P(O)OH and its potassium and dicyclohexylamine salts that reproduce the action of POCl(3) as in vitro AChE inhibitors and toxicants in mice. PSCl(3) on hydrolysis yields Cl(2)P(O)SH [which oxidizes with peracid to Cl(2)P(O)SOH] as the proposed activation product. Vapors of (EtO)(2)PCl, (EtO)(2)P(O)Cl, and (EtO)(2)P(S)Cl are lethal to houseflies as in vivo AChE inhibitors, the first two acting directly and the last one on oxidative activation to (EtO)(2)P(O)Cl (possibly by P450) or (EtO)(2)P(O)SCl (a phosphorylating agent in a peracid oxidation system). Thus PCl(3), (EtO)(2)PCl, and (EtO)(2)P(O)Cl act directly as AChE inhibitors whereas POCl(3) and PSCl(3) undergo hydrolytic activation and (EtO)(2)P(S)Cl undergoes oxidative activation. In contrast, the toxicity to mice of phosphofluorides [FP(O)Cl(2), F(Cl)P(O)OH, and F(2)P(O)OH; studied as model compounds for comparison] may be due to liberating fluoride ion.

PMID: 12641435 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12736191&dopt=Abstract

J Appl Physiol 2003 Jun;94(6):2423-2432

Altered myocardial Gs protein and adenylyl cyclase signaling in rats exposed to chronic hypoxia and normoxic recovery.

Hrbasova M, Novotny J, Hejnova L, Kolar F, Neckar J, Svoboda P.

Faculty of Natural Sciences, Department of Physiology and Developmental Biology, Charles University, Vinicna 7, Prague 2; Biochemistry of Membrane Receptors Group and Department of Developmental Cardiology, Institute of Physiology, Academy of Sciences of the Czech Republic, and Centre for Experimental Cardiovascular Research, Videnska 1083, Prague 4, Czech Republic.

The present work has analyzed the consequences of chronic intermittent high-altitude hypoxia for functioning of the G protein-mediated adenylyl cyclase (AC) signaling system in the right (RV) and left ventricular (LV) myocardium in rats. Adaptation to hypoxia did not appreciably affect the number of beta-adrenoceptors and the content of predominantly membrane-bound alpha-subunit (G(s)alpha) of the stimulatory G protein, but it raised the amount of cytosolic G(s)alpha in RV. The levels of myocardial inhibitory Galpha protein were not altered. Activity of AC stimulated by GTP, fluoride, forskolin, or isoprotertenol was reduced by approximately 50% in RV from chronically hypoxic rats, and a weaker depression was also found in LV. In addition, hypoxia significantly diminished a functional activity of membrane-bound G(s)alpha in both RV and LV. The RV baseline contractile function was markedly increased in chronically hypoxic animals, and its sensitivity to beta-adrenergic stimulation was decreased. Animals recovering from hypoxia for 5 wk still exhibited markedly elevated levels of cytosolic G(s)alpha and significantly lower activity of AC in RV than did age-matched controls, but contractile responsiveness to beta-agonists was normal.

PMID: 12736191 [PubMed - as supplied by publisher]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12576287&dopt=Abstract

J Inorg Biochem 2003 Jan 15;93(3-4):243-6

Substrate inhibition of rat liver and kidney arginase with fluoride.

Tormanen CD.

Department of Chemistry, Central Michigan University, 48858, Mount Pleasant, MI, USA

Fluoride is an uncompetitive inhibitor of rat liver arginase. This study has shown that fluoride caused substrate inhibition of rat liver arginase at substrate concentrations above 4 mM. Rat kidney arginase was more sensitive to inhibition by fluoride than liver arginase. For both liver and kidney arginase preincubation with fluoride had no effect on the inhibition. When assayed with various concentrations of L-arginine, rat kidney arginase did not have Michaelis-Menten kinetics. Lineweaver-Burk and Eadie-Hofstee plots were nonlinear. Kidney arginase showed strong substrate activation at concentrations of L-arginine above 4 mM. Within narrow concentrations of L-arginine, the inhibition of kidney arginase by fluoride was uncompetitive. Fluoride caused substrate inhibition of kidney arginase at L-arginine concentrations above 1 mM. The presence of fluoride prevented the substrate activation of rat kidney arginase.

PMID: 12576287 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12755503&dopt=Abstract

J Trace Elem Med Biol 2003;17(1):57-60

Activity of pancreatic antioxidative enzymes and malondialdehyde concentrations in rats with hyperglycemia caused by fluoride intoxication.

Chlubek D, Grucka-Mamczar E, Birkner E, Polaniak R, Stawiarska-Pieta B, Duliban H.

Department of Biochemistry and Chemistry, Pomeranian Medical University, Szczecin, Poland. dchlubek@pam.szczecin.pl

The aim of this work was to examine the effect of fluoride ions on antioxidative enzyme activity in the pancreas of rats exposed during 4 months to NaF in drinking water. The study was carried out in 30 four-week-old male Wistar FL rats, that were randomly assigned to three equal groups and given distilled water ad libitum for three weeks. Subsequently, two examined groups of animals were exposed to NaF in drinking water: group 1 (10 rats) at 50 mg F(-)/L (2.63 mmol/L), group 2 (10 rats) at 100 mg F(-)/L (5.26 mmol/L). The control group (10 rats) received distilled water. After 4 months the animals were anesthetized with ether prior to collection of pancreas and cardiac blood. Serum concentrations of glucose and fluoride, as well as activities of the cytoplasmic (CuZn-SOD) and the mitochondrial (Mn-SOD) superoxide dismutase, glutathione peroxidase (GSH-Px) and concentrations of malondialdehyde (MDA) in the homogenized pancreas were measured. The activity of CuZn-SOD was reduced by 50% and a tendency to lower activities of Mn-SOD was observed. No changes were noted in the activity of GSH-Px or concentrations of MDA. We conclude that:
1) the fluoride caused hyperglycemia in rats in this study is not accompanied by an activation of the free radical production in the pancreas;
2) the hyperglycemia in the exposed rats cannot be attributed to pancreatic damage caused by fluoride ions (the cause in this case appears to be extrapancreatic);
3) the inhibition of pancreatic CuZn-SOD is probably due to the direct action of fluoride on the enzyme.

PMID: 12755503 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12930675&dopt=Abstract
Zhonghua Yu Fang Yi Xue Za Zhi. 2003 Jul;37(4):256-8.
 
[Effects of fluoride on osteoclastic activity of rats in vitro]
 
[Article in Chinese]
 
Hua K, Bu LS, Li GS.
 
Department of Pathology, Institute of Endemic Disease, Jilin University, Changchun 130021, China.
 
OBJECTIVE: To investigate the effects of fluoride on activities of tartrate-resistant acid phosphate (TRAP) and matrix metallproteinase-9 (MMP-9) in rat osteoclasts cultured in vitro.
METHODS: Osteoclast was isolated mechanically from long bones of neonatal rats and cultured in vitro. Histochemical stain was applied to detect the effects of fluoride on activities of TRAP and in-situ hybridization was used to study the expression of MMP-9 mRNA in rat osteoclasts in vitro.
RESULTS: Number of TRAP positive cells was 154.2, 160.0, 170.6, 179.0 and 180.0 per cm(2), respectively for the rats with varied doses of fluoride, in a dose-response pattern but without statistical significance. The expression of MMP-9 mRNA increased with elevating dose of fluoride, especially in the rats with 1.00, 2.00 and 4.00 mg/L of fluoride, to 94.50, 94.64 and 104.97, respectively, significantly different from those in control group.
CONCLUSIONS: Fluoride can enhance the MMP-9 mRNA expression in cultured osteoclasts of rats.
 
PMID: 12930675 [PubMed - in process]
 

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12930674&dopt=Abstract
 
Zhonghua Yu Fang Yi Xue Za Zhi. 2003 Jul;37(4):251-5.
 
[Cloning of differentially displayed cDNAs involved in NaF-treated osteoblasts]
 
[Article in Chinese]
 
Miao Q, Liu BC, Zhang XC, You BR, Xu M, Kang N.
 
National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
 
OBJECTIVE: To explore the effects of excessive fluoride on the gene expression of rat osteoblasts.
METHODS: Rat osteoblasts were treated with 2.0 mmol/L of sodium fluoride (NaF) for two weeks in vitro, and difference in the gene expression between the NaF-treated and normal osteoblasts was compared with mRNA differential display (DD-PCR) technique.
RESULTS: Among the six differentially expressed gene fragments which had been cloned, expression of the ribosomal protein L5 gene, ATPase Na(+)K(+) transporting beta polypeptide 3 gene, karyopherin alpha 2 gene and cis-Golgi body p28 gene was lower and expression of ubiquitous-conjugating enzyme E2D 3 gene and a newly-discovered gene fragment in this study showed up-regulated in the NaF-treated osteoblasts of the rats.
CONCLUSIONS: Expression of genes changed in the osteoblasts after treatment with fluoride for two weeks and most of them associated with synthesis, transportation and processing of protein. It suggested that excessive fluoride could affect the protein synthesis in osteoblasts by changing the expression of the related genes. A novel gene related to excessive fluoride exposure was also found.
 
PMID: 12930674 [PubMed - in process]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12930673&dopt=Abstract

Zhonghua Yu Fang Yi Xue Za Zhi. 2003 Jul;37(4):246-50.

[Expression of proto-oncogenes c-fos and c-jun in osteoblasts activated by excessive fluoride]

[Article in Chinese]

Zhang WL, Cui YN, Gao S, Zhang XY, Li GS.

Department of Pathology, Institute of Endemic Disease, Jilin University, Changchun 130021, China.

OBJECTIVE: To study expression of proto-oncogenes c-fos and its accompanying gene c-jun in osteoblasts activated by action of excessive fluoride in vivo and in vitro.
METHODS: Experimental Wistar rats were exposed to sodium fluoride (NaF) added to their drinking water, and NaF was also added in cell culture supernatant for osteoblast-like cells in vitro. Expression of both mRNA and protein of c-fos and c-jun in bone-tissue of rats with chronic fluorosis and cultured osteoblast-like cells were determined by hybridization in situ, Western blot and immunohistochemistry at varied time periods after exposure.
RESULTS: Sodium fluoride could stimulate the proliferation of osteoblast in rats with chronic fluorosis and induce expression of both c-fos and c-jun in all envelops of the spine bone, as compared with its control group. Value of optical absorption in mRNA expression of c-fos and c-jun was 139.63 and 126.37, respectively, in rats with NaF plus high-calcium, significantly lower than that in control group with high-calcium only (107.74 and 117.48, respectively) (P < 0.001). Immunohistochemical analysis showed that protein level of c-fos and c-jun was significantly higher in rats with NaF plus high-calcium than that in control rats with high-calcium only, with values of optical absorption of 139.16, 131.15, 149.98 and 149.19 (P < 0.05), respectively, and protein level of c-fos and c-jun was signifcantly higher in rats with NaF plus low-calcium than that in control rats with low-calcium only, with values of optical absorption of 117.24, 111.46, 132.46 and 129.79 (P < 0.05), respectively. Western blotting showed that level of protein expression of c-fos and c-jun in periosteal osteoblasts was significantly higher in all rat groups with NaF than that in all control groups, with values of optical absorption of 123.32, 116.60, 115.97 and 108.30, respectively. mRNA expression of c-fos and c-jun in osteoblast-like cells treated with NaF for 12 h increased obviously, and remained at high level 48 h after exposure, with values of optical absorption of 114.80, 161.14, 118.20, and 150.41, respectively, as compared with that in control group (P < 0.001 and P < 0.05).
CONCLUSIONS: Exposure to excessive fluoride could stimulate activation and proliferation of both osteoblasts in rats and cultured osteoblast-like cells in vitro, and cause enhanced expression of mRNA and protein of both c-fos and c-jun. Over-expression of c-fos could play an important role in development and proliferation of skeletal lesions in rats with chronic fluorosis.

PMID: 12930673 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12930672&dopt=Abstract

Zhonghua Yu Fang Yi Xue Za Zhi. 2003 Jul;37(4):243-5.

[Expression of type II collagen gene and structural change in bone tissues of rats with experimental fluorosis]

[Article in Chinese]

Liu BC, Xu ZL, Miao Q, Xu YY, Xu M, Qian XJ, You BR, Yuan BH, Kang N.

National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China.

OBJECTIVE: To investigate the effects of excessive intake of fluoride on the expression of type II collagen gene and types and morphological change of collagen fiber in the bone tissues of rats.
METHODS: A rat model with fluorosis was established by adding 221 mg/L of sodium fluoride (NaF) to drinking water for the rats for 15 days, 30 days and two months, respectively. Type II collagen alpha1 (II) cDNA probe was prepared, and cDNA-mRNA in-situ hybridization was employed to detect change in expression of type II collagen mRNA in the bone tissues of rats with excessive intake of fluoride (221 mg/L NaF). Picrosirus-polarization method was used to observe types of collagen and morphology of collagen fiber in the bone tissues.
RESULTS: Chondroblasts were found in the femur and other bone tissues of the rats after exposure to fluoride. cDNA-mRNA in-situ hybridization showed that expression of type II collagen gene could be observed in the cytoplasm of chondrocytic lacuna and chondrified bone tissues. mRNA in collagen of chondrocytes of the rib cartilage reached the peak level 15 days after exposure to fluoride, and decreased gradually one month and two months after exposure. Polychromatic type II collagen, breakage of collagen fiber, disorder array and reduced content of type II collagen could be found in the bone tissues with picrosirius-polarization method.
CONCLUSIONS: Excessive intake of fluoride could lead to changes in types and structure of collagen (cross-linkage) of bone tissues, which caused expression of type II collagen gene in the chondrified bone tissues and enhanced its expression in the rib cartilage tissues.

PMID: 12930672 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12574006&dopt=Abstract

Acad Emerg Med 2003 Feb;10(2):105-9

Amiodarone Attenuates Fluoride-induced Hyperkalemia in Vitro.

Su M, Chu J, Howland MA, Nelson LS, Hoffman RS.

New York University/Bellevue Hospital Center and the New York City Poison Control Center (MS, MAH, LSN, RSH), New York, NY.

Poisoning by hydrofluoric acid or fluoride salts results in hypocalcemia, hypomagnesemia, and hyperkalemia with subsequent cardiac dysrhythmias. In previous studies, quinidine attenuated fluoride-induced hyperkalemia in vitro, and enhanced survival in animals. Like quinidine, amiodarone is a potassium channel blocker, although amiodarone is more familiar to clinicians due to its recent inclusion in advanced cardiac life support (ACLS) protocols.
OBJECTIVES: This in-vitro study of human erythrocytes was designed to determine whether amiodarone could attenuate fluoride-induced hyperkalemia.
METHODS: Six healthy volunteers each donated 60 mL of blood on three occasions. Each specimen was divided into 12 tubes, incubated at 37 degrees C, and oxygenated with room air. An aqueous sodium fluoride (F(-)) solution was added to tubes 1-9. Incremental amounts of quinidine were added to tubes 1-4 (Q(1)-Q(4)) to attain calculated concentrations of 0.73 micro g/mL, 1.45 micro g/mL, 2.9 micro g/mL, and 5.8 micro g/mL, respectively. Incremental amounts of amiodarone were added to tubes 5-8 (A(1)-A(4)) to attain calculated concentrations of 0.38 micro g/mL, 0.75 micro g/mL, 1.5 micro g/mL, and 3.0 micro g/mL, respectively. Tubes 9-12 were controls for each of F(-), amiodarone, quinidine alone, and no additive, respectively. Extracellular potassium concentration ([K(+)]) was followed, and an objective endpoint was defined as the rise in potassium concentration at 6 hours.
RESULTS: Fluoride produced a significant change in [K(+)] by 6 hours in all samples. Quinidine produced a J-shaped curve in its ability to attenuate the rise in [K(+)], with only one concentration, Q(3), demonstrating significance versus tube 9 (control). Amiodarone also demonstrated a J-shaped dose-response effect, with statistical significance at A(1), A(2), and A(3) versus tube 9 (control). There was no significant difference among the effective concentrations (Q(3), A(1), A(2), and A(3)) of both drugs.
CONCLUSIONS: In this in-vitro model using human blood, amiodarone and quinidine both attenuated F(-)-induced hyperkalemia. Further study is indicated to determine whether amiodarone enhances survival in F(-)-poisoned animals.

PMID: 12574006 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12538343&dopt=Abstract
 
Carcinogenesis 2003 Jan;24(1):7-15

Short-term depletion of catalase suppresses cadmium-elicited c-Jun N-terminal kinase activation and apoptosis: role of protein phosphatases.

Chuang SM, Wang IC, Hwua YS, Yang JL.

Molecular Carcinogenesis Laboratory, Department of Life Sciences, National Tsing Hua University, Hsinchu 300, Taiwan, Republic of China.

The c-Jun N-terminal kinase (JNK) is a vital stress-activated signal that can be regulated differentially under oxidant or antioxidant conditions. Recently, we have reported that activation of JNK by cadmium chloride (Cd) contributes to apoptosis in CL3 human lung adenocarcinoma cells. Although oxidative stress has been implicated in numerous biochemical effects altered by Cd, its role in Cd-elicited JNK activation has not been established. Here we report that catalase is crucial for the activation of JNK by Cd. Short-term treatment of 3-amino-1,2,4-triazole (3AT), a specific catalase inhibitor, completely suppressed the Cd-elicited JNK activation, conversely, exogenous addition of catalase increased the intensity and duration of JNK activation in Cd-treated CL3 cells. Co-administering high doses of H(2)O(2) (500-1000 micro M) with Cd also markedly decreased JNK activity, although at doses <200 micro M H(2)O(2) enhanced the Cd-elicited JNK activation in CL3 cells. 3AT also blocked JNK activation in Cd-treated normal human fibroblasts and Chinese hamster ovary cells, and in UV-irradiated CL3 cells. However, mannitol, a hydroxyl radical scavenger, did not alter the JNK activity in Cd-treated human and rodent cells. Intriguingly, sodium fluoride or okadaic acid, inhibitors for serine/threonine protein phosphatases (PP), recovered the JNK activity in CL3 cells exposed to Cd plus 3AT; however, the protein tyrosine phosphatases inhibitor sodium orthovanadate did not. Furthermore, 3AT decreased but catalase increased the Cd-induced cytotoxicity, apoptosis and procaspase-3 degradation in CL3 cells. Together, these results indicate that persistent activation of apoptotic JNK signal by Cd requires functional catalase and that short-term depletion of catalase activity may facilitate okadaic acid-sensitive PP to down-regulate the JNK activation and may predispose these cells to carcinogenic transformation upon Cd exposure.

PMID: 12538343 [PubMed - in process]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12624697&dopt=Abstract
Anaesthesist 2003 Feb;52(2):127-31

[Emergency from anesthesia in small children. From laryngospasm to prolonged apnea]

[Article in German]

Gries A, Motsch J, Ulmer HE, Springer W.

Klinik fur Anaesthesiologie der Universitat Heidelberg.

Postoperative laryngospasm during emergence from anaesthesia represents a potentially life-threatening complication.Even if this is successfully overcome using drug therapy, new, serious problems may develop.We report the case of a 31/2 -year-old boy of African descent weighing 15 kg who developed a laryngospasm during emergence from anaesthesia.Because the airway obstruction could not be controlled by deepening the anaesthesia again and administering anti-obstructive drugs, the boy was given 15 mg succinylcholine.Thereafter prolonged apnea developed such that the patient had to be admitted to the pediatric intensive care unit.The child was extubated 6 h later and the further course was normal so that he could be released from the hospital the following day.Further diagnostic study revealed a dibucaine-sensitive, fluoride-resistant pseudocholinesterase in the plasma, which is a rare form of atypical pseudocholinesterase, explaining the prolonged arousal phase after the administration of succinylcholine.Three significant aspects of this case are discussed: 1. risk factors and treatment of perioperative airway obstruction 2. factors and treatment of prolonged apnea, and 3. delayed arousal reactions and their management in an outpatient setting.

PMID: 12624697 [PubMed - in process]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12746444&dopt=Abstract

J Biol Chem 2003 May 13; [epub ahead of print]

The ATP hydrolysis cycle of the nucleotide-binding domain of the mitochondrial ABC transporter Mdl1p.

Janas E, Hofacker M, Chen M, Gompf S, Van Der Does C, Tampe R.

Biocenter Frankfurt, Institute of Biochemistry, Frankfurt a.M. 60439.

The ABC transporter Mdl1p, a structural and functional homologue of the transporter associated with antigen processing (TAP) plays an important role in intracellular peptide transport from the mitochondrial matrix of Saccharomyces cerevisiae. To characterize the ATP hydrolysis cycle of Mdl1p, the nucleotide-binding domain (NBD) was overexpressed in E. coli and purified to homogeneity. The isolated NBD was active in ATP binding and hydrolysis with a turnover of 25 ATP per minute and a Km of 0.6 mM and did not show cooperativity in ATPase activity. However, the ATPase activity was non-linearly dependent on protein concentration (Hill coefficient of 1.7), indicating that the functional state is a dimer. Dimeric catalytic transition states could be trapped either by incubation with ortho-vanadate or beryllium fluoride, or by mutagenesis of the NBD. The nucleotide composition of trapped intermediate states was determined using [alpha-32P]-ATP and [gamma-32P]-ATP. Three different dimeric intermediate states were isolated, containing either two ATPs, one ATP and one ADP, or two ADPs. Based on these experiments, it was shown that
i) ATP binding to two NBDs induces dimerization,
ii) in all isolated dimeric states, two nucleotides are present,
iii) phosphate can dissociate from the dimer,
iv) both nucleotides are hydrolyzed, and
v) hydrolysis occurs in a sequential mode.
Based on these data, we propose a processive-clamp model for the catalytic cycle in which association and dissociation of the NBDs depends on the status of bound nucleotides.

PMID: 12746444 [PubMed - as supplied by publisher]


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16414571&query_hl=3&itool=pubmed_docsum

Pak J Pharm Sci. 2003 Jul;16(2):9-11.

CLINICAL INVESTIGATIONS OF SKELETAL FLUOROSIS IN CHILDREN OF MANGA MANDI IN PAKISTAN.

Ahmad M, Ahmad B, Nawazish-I-Hussain S, Mahmood S.

Department of Pharmacy, Bahauddin Zakariya University, Multan, Pakistan.

In July 2000 about 124 children were detected suffering from skeletal fluorosis at Manga Mandi near Lahore. They were drinking high fluoride (maximum level 29 ppm) containing water. We have studied various biochemical parameters in serum, including alkaline phosphatase, calcium and inorganic phosphorus. These levels were compared with the levels of those children who were the brothers and/or sisters of the patients (patient control) and had a dental fluororsis of varying degree. These levels were also compared with the serum levels of normal children (normal control). Serum samples were analyzed using standard kits of Boringer Mannham and Randox. Serum alkaline phosphatase levels of patients, patient control and normal control were 291.68 &plusmn; 121.06 (mean &plusmn; SD, n=8), 196.58 &plusmn; 45.71 (n=10) and 144.85 &plusmn; 39.77 (U/L) respectively. Serum calcium levels of patient, patient control and normal control were 1.44 &plusmn; 0.08, 1.41 &plusmn; 0.14 and 1.28 &plusmn; 0.13 (m. mol/L) respectively. Serum inorganic phosphorus levels of patient, patient control and normal control were 1.55 &plusmn; 0.08, 1.65 &plusmn; 0.09 and 1.69 &plusmn; 0.04 (m.mol/L) respectively. These results enable us to conclude that blood calcium and phosphorus may play a major role for the determination of skeletal fluorosis whereas alkaline phosphatase may be having a minor importance.

PMID: 16414571 [PubMed - as supplied by publisher]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12745716&dopt=Abstract

Scand J Urol Nephrol 2003;37(2):99-105

Diminished Expression of Aquaporin Water Channels in Ureteral-obstructed Kidney in Rats.

Yeum CH, Kim SW, Lee SC, Choi KC, Ahn KY, Lee J.

Department of Internal Medicine, Cheju National University Medical School, Jeju, South Korea.

Objective: We investigated whether regulation of aquaporin (AQP) water channels is altered in the ureteral-obstructed kidney.
Material and Methods: Male Sprague-Dawley rats were unilaterally obstructed of their left proximal ureters for 48 h. The protein expression of AQP1-3 channels was determined in the kidney by Western blot analysis. The expression of AQP2 was also determined by immunohistochemistry. In order to specifically determine primary impairment of the pathway leading to an altered regulation of AQP channels stimulated by the arginine vasopressin (AVP)/cyclic adenosine monophosphate (cAMP) pathway, the catalytic activity and protein expression of different parts of the adenylyl cyclase complex were separately determined.
Results: In the previously obstructed kidney, urinary osmolality and free water reabsorption were greatly decreased. The expression of AQP2 proteins was decreased in the cortex, outer medulla and inner medulla. Immunohistochemistry also showed a marked decrease in AQP2 expression. The expression of AQP1 and AQP3 was decreased in the outer medulla and inner medulla. cAMP generation in response to AVP, sodium fluoride or forskolin was greatly decreased. The expression of Gsalpha and adenylyl cyclase VI proteins was decreased. The contralateral kidney showed minimal or no changes in these parameters.
Conclusions: The reduced abundance of AQP water channels may at least partly account for the urinary concentration defect in the ureteral-obstructed kidney. The primary point of impairment of AQP channels regulated by the AVP/cAMP pathway may lie at the level of the catalytic unit of adenylyl cyclase.

PMID: 12745716 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12742022&dopt=Abstract

J Mol Biol 2003 May 23;329(1):121-34

The Allosteric Transition of GroEL Induced by Metal Fluoride-ADP Complexes.

Inobe T, Kikushima K, Makio T, Arai M, Kuwajima K.

Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033, Tokyo, Japan

To understand the mechanism of a functionally important ATP-induced allosteric transition of GroEL, we have studied the effect of a series of metal fluoride-ADP complexes and vanadate-ADP on GroEL by kinetic fluorescence measurement of pyrene-labeled GroEL and by small-angle X-ray scattering measurement of wild-type GroEL. The metal fluorides and vanadate, complexed with ADP, are known to mimic the gamma-phosphate group of ATP, but they differ in geometry and size; it is expected that these compounds will be useful for investigating the strikingly high specificity of GroEL for ATP that enables the induction of the allosteric transition. The kinetic fluorescence measurement revealed that aluminium, beryllium, and gallium ions, when complexed with the fluoride ion and ADP, induced a biphasic fluorescence change of pyrenyl GroEL, while scandium and vanadate ions did not induce any kinetically observed change in fluorescence. The burst phase and the first phase of the fluorescence kinetics were reversible, while the second phase and subsequent changes were irreversible. The dependence of the burst-phase and the first-phase fluorescence changes on the ADP concentration indicated that the burst phase represents non-cooperative nucleotide binding to GroEL, and that the first phase represents the allosteric transition of GroEL. Both the amplitude and the rate constant of the first phase of the fluorescence kinetics were well understood in terms of a kinetic allosteric model, which is a combination of transition state theory and the Monod-Wyman-Changeux allosteric model. From the kinetic allosteric model analysis, the relative free energy of the transition state in the metal fluoride-ADP-induced allosteric transition of GroEL was found to be larger than the corresponding free energy of the ATP-induced allosteric transition by more than 5.5kcal/mol. However, the X-ray scattering measurements indicated that the allosteric state induced by these metal fluoride-ADP complexes is structurally equivalent to the allosteric state induced by ATP. These results suggested that both the size and coordination geometry of gamma-phosphate (and its analogs) are related to the allosteric transition of GroEL. It was therefore concluded that the tetrahedral geometry of gamma-phosphate (or its analogs) and the inter-atomic distance ( approximately 1.6A) between phosphorus (vanadium, or metal atom) and oxygen (or fluorine) are both important for inducing the allosteric transition of GroEL, leading to the high selectivity of GroEL for ATP about ligand adenine nucleotides, which function as the preferred allosteric ligand.

PMID: 12742022 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12642968&dopt=Abstract

Arzneimittelforschung. 2003;53(2):121-5.
Developmental toxicity studies of the quinolone antibacterial agent irloxacin in rats and rabbits.

Guzman A, Garcia C, Marin AP, Willoughby C, Demestre I.

Toxicology Department, Laboratorios Dr. Esteve S.A., Barcelona, Spain.

Embryotoxicity studies on irloxacin (6-fluorine-7-(pyrrol-1-yl)-1-ethyl-1,4-dihydro-4-oxo-quinolone-3-carboxylic acid, CAS-91524-15-1), a new fluoroquinolone antibacterial agent, were performed in rats and rabbits. Oral administration of irloxacin during the fetal period of organogenesis to pregnant rats and rabbits at dose levels of up to 1000 and 350 mg/kg/d, respectively, elicited no evidence of teratogenicity. During the first days of treatment, transient stasis in body weight increase was observed in rat dams receiving doses of 350 or 1000 mg/kg/d, and reduced food consumption was observed in those receiving 1000 mg/kg/d. Necropsy on day 20 of gestation showed dosage related increase in liver and kidney weights in all rat treated groups. Rabbit dams receiving 350 mg/kg/d showed during the first days of treatment decrease in body weight, and decreased food consumption and faecal output. Also, four females receiving 350 mg/kg/d aborted between days 18 and 20 of gestation. Rat fetuses in the 350 and 1000 mg/kg/d showed decreased body weight, and a decrease in placental weights was observed in the 1000 mg/kg/d group. No retardations or malformations were observed in rat or rabbit fetuses at any tested dose level. For maternal and embryo-fetal effects 100 and 150 mg/kg/d can be considered as the no-effect-level (NOEL) for rats and rabbits, respectively.

PMID: 12642968 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12723949&dopt=Abstract
J Med Chem. 2003 May 8;46(10):1858-69.
 
Effects of heterocyclic aromatic substituents on binding affinities at two distinct sites of somatostatin receptors. Correlation with the electrostatic potential of the substituents.
 
Prasad V, Birzin ET, McVaugh CT, Van Rijn RD, Rohrer SP, Chicchi G, Underwood DJ, Thornton ER, Smith AB 3rd, Hirschmann R.
 
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
 
In our continuing program exploring glucose-based peptidomimetics of somatostatin (SRIF-14), we sought to improve the water solubility of our glycosides. This led to insights into the nature of the ligand binding sites at the SRIF receptor. Replacement of the C4 benzyl substituent in glucoside (+)-2 with pyridinylmethyl or pyrazin-2-ylmethyl congeners increased water solubility and enhanced affinity for the human SRIF subtype receptor 4 (sst4). We attribute this effect to hydrogen bond formation. The pyridin-3-ylmethyl substituent at C4, when combined with the imidazol-4-ylmethyl group at C2, generated (-)-19, which has the highest affinity of a glucose-based peptidomimetic at a human SRIF receptor to date (K(i) 53 +/- 23 nM, n = 6 at sst4). The C4 heterocyclic congeners of glucosides bearing a 1-methoxy substituent rather than an indole side chain at the anomeric carbon, such as (+)-16, also provided information about the Trp(8) binding pocket. We correlated the SARs at both the C4 and the Trp(8) binding pockets with calculations of the electrostatic potentials of the diverse C4 aromatic substituents using Spartan 3-21G(*) MO analysis. These calculations provide an approximate analysis of a molecule's ability to interact within a receptor binding site. Our binding studies show that benzene and indole rings, but not pyridinylmethyl nor pyrazin-2-ylmethyl rings, can bind the hydrophobic Trp(8) binding pocket of sst4. The Spartan 3-21G(*) MO analysis reveals significant negative electrostatic potential in the region of the pi-clouds for the benzene and indole rings but not for the pyridinylmethyl or pyrazin-2-ylmethyl congeners. Our data further demonstrate that the replacement of benzene or indole side chains by heterocyclic aromatic rings typified by pyridine and pyrazine not only enhances water solubility and hydrogen bonding capacity as expected, but can also profoundly diminish the ability of the pi-cloud of the aromatic substituent to interact with side chains of an aromatic binding pocket such as that for Trp(8) of SRIF-14. Conversely, these calculations accommodate the experimental findings that pyrazin-2-ylmethyl and pyridinylmethyl substituents at C4- of C1-indole-substituted glycosides afford higher affinities at sst4 than the C4-benzyl group of (+)-2. This result is consistent with the high electron density in the plane of the heterocycle depicted in Figure 6 which can accept hydrogen bonds from the C4 binding pocket of the receptor. Unexpectedly, we found that the 2-fluoropyridin-5-ylmethyl analogue (+)-14 more closely resembles the binding affinity of (+)-8 than that of (+)-2, thus suggesting that (+)-14 represents a rare example of a carbon linked fluorine atom acting as a hydrogen bond acceptor. We attribute this result to the ability of the proton to bind the nitrogen and fluorine atoms simultaneously in a bifurcated arrangement. At the NK1 receptor of substance P (SP), the free hydroxyl at C4 optimizes affinity.
 
PMID: 12723949 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12841225&dopt=Abstract
 
Chem Commun (Camb). 2003 Jun 21;(12):1321-6.

Carbon-fluorine bond activation--looking at and learning from unsolvated systems.

Mazurek U, Schwarz H.

Institut fur Chemie, Technische Universitat Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany.

The selective activation of a particular bond in a molecule has always been a desideratum in chemical synthesis. This Feature Article focuses on studying the mechanisms operative in the activation of carbon-fluorine bonds beyond solvated systems, i.e., on surfaces and in the gas phase. Side glances to reactions in solutions, however, are incorporated when appropriate.

PMID: 12841225 [PubMed - in process]

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15143768

Yakushigaku Zasshi. 2003;38(2):161-79.

[The history of the development and changes of quinolone antibacterial agents]

[Article in Japanese]

Takahashi H, Hayakawa I, Akimoto T.

Medical Chemistry Research Laboratory, Tokyo R & D Center,.

The quinolones, especially the new quinolones (the 6-fluoroquinolones), are the synthetic antibacterial agents to rival the Beta-lactam and the macrolide antibacterials for impact in clinical usage in the antibacterial therapeutic field. They have a broad antibacterial spectrum of activity against Gram-positive, Gram-negative and mycobacterial pathogens as well as anaerobes. Further, they show good-to-moderate oral absorption and tissue penetration with favorable pharmacokinetics in humans resulting in high clinical efficacy in the treatment of many kinds of infections. They also exhibit excellent safety profiles as well as those of oral Beta-lactam antibiotics. The bacterial effects of quinolones inhibit the function of bacterial DNA gyrase and topoisomerase IV. The history of the development of the quinolones originated from nalidixic acid (NA), developed in 1962. In addition, the breakthrough in the drug design for the scaffold and the basic side chains have allowed improvements to be made to the first new quinolone, norfloxacin (NFLX), patented in 1978. Although currently more than 10,000 compounds have been already synthesized in the world, only two percent of them were developed and tested in clinical studies. Furthermore, out of all these compounds, only twenty have been successfully launched into the market. In this paper, the history of the development and changes of the quinolones are described from the first quinolone, NA, via, the first new quinolone (6-fluorinated quinolone) NFLX, to the latest extended-spectrum quinolone antibacterial agents against multi-drug resistant bacterial infections. NA has only modest activity against Gram-negative bacteria and low oral absorption, therefore a suitable candidate for treatment of systemic infections (UTIs) is required. Since the original discovery of NA, a series of quinolones, which are referred to as the old quinolones, have been developed leading to the first new quinolone, NFLX, with moderate improvements in over all properties starting in 1962 through and continuing throughout the 1970's. Especially, the drug design for pipemidic acid (PPA) indicated one of the important breakthroughs that lead to NFLX. The introduction of a piperazinyl group, which ia a basic moiety at the C7-position of the quinolone nuclei, improved activity against Gram-negative organisms broadening the spectrum to include Pseudomonas aeruginosa. PPA also showed soem activity against Gram-positive bac teria. The basic piperazine ring, which can form the zwitterionic natrure with the carboxylic acid at the C3-position, has subsequently been shown to increase the ability of the drugs to penetrate the bacterial cells resulting in enhanced activity. Further, the zwitterionic forms resulted in significant tissue penetration in the pharmacokinetics. On the other hand, the first compound with a fluorine atom at the C6-position of the related quinolone scaffold was flumequine and the compound indicated that activity against Gram-positive bacteria could be improved in the old quinolones. The addition of a flourine atom at the C6-position is essential for the inhibition of target enzymes. The results show the poten antibacterial activity and the penetration of the quinolone molecule into the bacterial cells and human tissue. The real breakthrough came with the combination of these two features in NFLX, a 6-fluorinated quinolone having a piperazinyl group at the C7-position, NFLX features significant differences from the old quinolones in the activities and pharmacokinetics in humans, resulting in high clinical efficacy in the treatment of many kinds of infections including RTIs.Consequently, those great discoveries are rapidly superseded by even better compounds and NFLX proved to be just the beginning of a highly successful period of research into the modifications of the new quinolone antibacterials. Simce the chemical structure and important features of NFLX had become apparent in 1978, many compounds were patented in the next three years, several of which reached the market. Among the drugs, ofloxacin (OFLX) and ciprofloxacin (CPFX) are recognized as superior in several respects to the oral beta-lactam antibiotics as an antibacterial agent. With a focus on OFLX and CPFX, numerous research groups entered the antibacterial therapeutic field, triggering intense competition in the search to find newer, more effective quinolones. After NFLX was introduced in the market, while resulting by the end of today, eleven kinds of other new quinolones launched in Japan. They are enoxacin (ENX), OFLX, CPFX, lomefloxacin (LFLX), fleroxacin (FRLX), tosufloxacin (TFLX), levofloxacin (LVFX), sparfloxacin (SPFX), gatifloxacin (GFLX), prulifloxacin (PULX) and also pazufloxacin (PZFX). The advantages of these compounds, e.g., LVFX, SPFX and GFLX, are that their spectrum includes Gram-positive bacteria species as well as Gram-negative bacteria and they improve bioavailability results when a daily dose is administered for systemic infections including RTIs. However, unexpected adverse reactions, such as the CNS reaction, the drug-drug interaction, phototoxicity, hepatotoxicity and cardiotoxicity such as the QTc interval prolongation of ECG, have been reported in the clinical evaluations or the post-marketing surveillance of several new quinolones. Moreover, the adverse reactions of arthropathy (the joint toxicity) predicated from studies in juvenile animals have never materialized in clinical use. Therefore, no drugs other than NFLX have yet been approved for pediatric use. Fortunately, the newer quinolones are being developed and tested to reduce these adverse reactions on the basis of recent studies. On the other hand, multi-drug resistant Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative staphycolocci (MRCNS), penicillin-resistant Streptococcus pneumoniae (PRSP) and vancomycin-resistant enterococci (VRE) have been a serious problem in the medical community. Recently, the new quinolone antibacterials are highly successful class of antibacterial therapeutic field, however, the increased isolation of quinolone-resistant bacteria above them has become a normal outcome. These problems of multi-drug resistance have been the driving force for the development of newer quinolones. The next gereration of quinolone antibacterial agents will be potent against multi-drug resistant bacteria, such as MRSA, and provide a lower rate of emergence in resistance. Further, they should have favorable safety profiles to reduce the adverse reactions. The future of quinolones as the ultimate in pharmaceuticals must be handled cautiously if they are to realize their potential in the medical community.

PMID: 15143768 [PubMed - in process]


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