Endemic fluorosis in Henan province, China: ERα gene polymorphisms and reproductive hormones among women.

BACKGROUND AND OBJECTIVES: The aim of this study was to explore the influence of fluoride exposure and ERα gene polymorphisms on reproductive hormone concentrations of women in accordance with endemic fluorosis residence. METHODS AND STUDY DESIGN: A cross sectional study was conducted in Tongxu county, Henan Province, China. A total of 679 women were recruited using cluster sampling and each subject provided fasting blood and an associated urine sample. We measured the concentrations of serum gonadotropin releasing hormone (GnRH), follicle-stimulating hormone, luteinizing hormone, and estradiol and urinary fluoride. RESULTS: In the defluoridation project group (DFPG), serum GnRH was lower in women carrying C/C genotype compared to in those carrying C/T and T/T genotypes of ERα gene rs3798577 (p<0.05). In the endemic fluorosis group (EFG), serum GnRH was lower in women carrying Pp genotype compared to in those carrying PP and pp genotypes of ERα PvuII (p<0.05). Serum GnRH in women from EFG who carried Pp, pp, Xx and xx genotypes in ERα gene PvuII and XbaI was lower than in those in the control group (CG) who carried same genotypes (p<0.05). Furthermore, serum GnRH in women from EFG was significantly lower than in those in CG, regardless of whether the women were carrying C/C, C/T or T/T genotypes of ERα rs3798577 (p<0.05). Serum estradiol concentrations in EFG were significantly lower than in CG when the women were carrying the Pp, Xx and T/T genotypes in ERα gene (p<0.05). CONCLUSION: Interaction of ERα gene and fluoride exposure may influence women's serum reproductive hormone concentrations.

Serum calciotropic hormone levels, and dental fluorisis in children exposed to different concentrations of fluoride and iodine in drinking water.

BACKGROUND: High fluoride exposure can result in dental fluorosis. Fluoride and iodine are coexistent in the drinking water of areas in China and may affect the prevalence of dental fluorosis and osteogenesis. The aim of this study was to investigate the relationship between serum calciotropic hormone level, and dental fluorisis in children exposed to different concentrations of fluoride and iodine in drinking water. METHODS: A pilot study was conducted in three villages located in the Kaifeng and Tongxu counties of Henan Province, China in 2006. Children aged 8 to 12 years, born and raised in the three villages were recruited. The fluoride levels in the samples of urine from these children were detected by fluoride ion selective electrode. Calcitonin and osteocalcin levels in the serum, and serum calcium were measured by radioimmunassay and flame atomic absorption spectrometry, respectively. RESULTS: Fluoride levels in urine were significantly lower in children from control area (CA) as compared with those from the high fluoride & iodine areas (HFIA) and the high fluoride area (HFA) (P < 0.05 respectively), and no statistically significant difference was found between the children from HFIA and HFA. Additionally, calcitonin levels in the serum were significantly lower in children from CA and HFA as compared with that from HFIA (P < 0.05 respectively), and osteocalcin levels in the serum was lower in children from CA than those from HFIA (P < 0.05). No statistically significant difference in serum osteocalcin concentrations was found between children from HFA and HFIA. CONCLUSION: This study provides an evidence that iodine exposure may modify the serum calciotropic hormone levels related to fluorine exposure.

Improved absorption of salmon calcitonin by ultraflexible liposomes through intranasal delivery.

The objective of this work was to explore the potential of ultraflexible liposomes as carriers for improving the absorption of salmon calcitonin (sCT) through intranasal administration. The average diameters of positively charged ultraflexible liposomes ranged from about 73 to 99 nm, while those of negatively charged ones were 114 and 157.6 nm, respectively. The content of sodium deoxycholate in liposomes markedly affected the size and encapsulated efficiency of liposomes. The absorption of sCT through intranasal administration was evaluated by hypocalcemic efficacy in rats. The total Ca decrease D% of sCT-loaded ultraflexible liposomes with positive and negative charges were significantly bigger than that of sCT solution, while there was no significant difference in the hypocalcemic efficacy between plain liposome and sCT solution. Unexpectedly, the hypocalcemic efficacy of sCT-loaded ultraflexible liposomes with positive charges was not significantly better than those with negative charges. The decrease rate and extent of the serum calcium level for subcutaneous injection of sCT solution were almost equivalent to those for intranasal administration of negatively and positively charged ultraflexible liposomes within the first 2h, indicating that the ultraflexible liposomes could quickly enhance the penetration of the drug during their residence in the nasal cavity. The results of the toxicity of sCT-loaded ultraflexible liposomes to nasal mucosa demonstrated that the ultraflexible liposomes exerted slight toxicity on the nasal mucosa. On an overall evaluation, the ultraflexible liposomes may be a useful vehicle for intranasal delivery of sCT.