Inhibitory effect of fluoride on the secretion of insulin

Summary The oral administration of sodium fluoride (NaF) (40 μmol/100 body weight [bw]) to fasting rats produced an immediate fall in insulin levels and the consequent increase in glycemia. These phenomena were observed with plasma fluoride concentrations 5–15 μM. Glycemia and insulin returned to normal levels within 4–5 hours, together with the washing out of fluoride from plasma and soft tissues. The insulin secretion of isolated Langerhans islets, perifused with solutions containing 5, 10, or 20 μM fluoride, was found to be significantly inhibited as a function of fluoride levels, both with basal and stimulatory concentrations of glucose. One hour after the intake of 60 mg of NaF, fasting human volunteers showed increased fluoride (5–15 μM) together with a significant fall of plasma insulin levels.     

Effect of intraperitoneally injected fluoride on plasma calcium in suckling and adult rats

Summary Sodium fluoride 10, 20, or 40 mg/kg body weight was given intraperitoneally to rats (6–11 days old and 90–95 days old). Blood analyses showed an initial increase in plasma fluoride concentration. The subsequent decrease in fluoride was paralleled by a decrease in total plasma calcium. These plasma concentrations were normal at blood collection 4 days after fluoride injection. The baby rats differed from the older rats in that their initial plasma calcium was higher and that the drop in plasma calcium concentration was less pronounced than in the old rats. A diet low in calcium and phosphate enhanced the effects of fluoride on total plasma calcium. The data indicate that the effect of large doses of fluoride on lowering the plasma calcium level is modified by the calcium intake.     

扩散－电极法测定食品中氟

样品中氟在扩散盒中与硫酸作用生成氟化氢，经扩散吸附在扩散盒的碱膜上。碱膜用缓冲液溶解后，氟化物含量由氟离子选择电极测定。用本法对菜花、菠菜、大米、鱼片干四种样品以及玉米氟样品的氟进行了精密度和准确度试验。相对标准偏差在５％以内，回收率为９０％～１０３％，最小检测量为０．２４μｇ。该法可直接测定含氟量在０．５～１００ｍｇ／ｋｇ（干重）的食品。     

3种氟素制剂氟离子进入离体乳牙釉质内含量的比较研究

目的：比较3种氟素制剂对离体乳牙釉质氟含量的影响。方法：24个乳前牙随机分为3组，各牙冠唇舌向均分为两半，分别开窗，酸蚀，随机将其中1个作为实验区分配给1种氟素制剂处理，另1个作对照。1、2、3组实验区分别用10％（NH4）2MoO2F4溶液、38％Ag(NH3)2F溶液和APF－LaCl3溶液联用处理3min，对照区去离子水处理。将经处理的标本各置入4ml 0.1mol/L乳酸中，48h后终止1、2组试验，第3组持续至144h。用氟离子电极法测定各管溶液内氟离子浓度，统计分析。结果：3种氟素制剂处理后，离体乳牙釉质中均有氟摄入；釉质氟增量以APF－LaCl3溶液联用组最多，38％Ag(NH3)2F溶液组次之，10％（NH4）2MoO2F4溶液组最少。结论：3种氟素制剂均可增加离体乳牙釉质内氟含量，其中APF－LaCl3溶液联用作用最强，10％（NH4）2MoO2F4溶液最弱。     

Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride

In enamel fluorosis model rats treated with sodium fluoride, secretory ameloblasts of incisor tooth germs exhibited disruption of intracellular trafficking. We examined whether heterotrimeric G proteins participated in the disruption of vesicular trafficking of the secretory ameloblast exposed to fluoride, using immunoblotting and pertussis toxin (IAP)-induced adenosyl diphosphate (ADP)-ribosylation for membrane fractions of the cell. Immunoblotting of crude membranes, post supernatants of the ameloblast, with anti-G_i3/o and anti-G_s antibodies showed that G_i3 or G_o proteins existed in the secretory ameloblast, but G_s protein did not. Immunoblotting of the subcellular membrane fractions indicated that the G_i3 or G_o proteins were located in the Golgi membrane, but were not in the rough endoplasmic reticulum (rER) membrane. Autoradiograph of IAP-induced ADP-ribosylation, however, showed the existence of IAP-sensitive G proteins both in rER and Golgi membranes. Fluoride treatment decreased the G proteins bound to both membranes. These findings indicate that different G proteins, both of which are IAP-sensitive, are present in the rER and Golgi apparatus, and suggest that these G proteins participate in the disturbance of intracellular transport of the secretory ameloblast exposed to fluoride. Received: 24 June 1998 / Accepted: 8 September 1998     

拮氟锐对大鼠肠道氟吸收及微量元素的影响

拮氟锐是由硼、微量元素和中药制成的抗氟药物。本文应用肠道原位灌流技术。观察了拮氟锐对大鼠肠道氟吸收的干预作用及微量元素的影响。结果透明：拮氟锐可促进肠道ＢＦ４的形成，使氟吸收量减少，血氟降低。同时，拮氟锐可拮抗氟所致的微量元素的降低。与硼锌组比较，拮氟锐的抗氟作用效果更明显。     

萍乡地区空气污染型氟中毒的氟化物转移特点

为探讨萍乡地区空气污染型氟中毒的氟化物转移特点，对萍乡地区环境地质进行了调查，并对土壤及水中氟化物进行测定，结果显示该地区环境地质背景类似于半湿润富铁铝地球化学环境，中性和酸性土壤氟化物聚集区，由于该地区的地质特点形成氟化物富集的土壤，这正是当地居民拌煤和烧制砖瓦的主要原料，煤和土壤在燃烧过程中排出大量氟化物，污染空气水和食物等，危害人群的健康，引起氟中毒。     

Electrochemical release testing of nickel-titanium orthodontic wires in artificial saliva using thin layer activation

Alloys based on Ni–Ti intermetallics generally exhibit special shape memory and pseudoelastic properties, which make them desirable for use in the dental field as orthodontic wires. The possibility of nickel release from these materials is of high concern, because the allergenicity of this element. The aim of this study was to test pseudoelastic Ni–Ti wires in simulated physiological conditions, investigating the combined effect of strain and fluoridated media: the wires were examined both under strained (5% tensile strain) and unstrained conditions, in fluoridated artificial saliva at 37 °C. Real time electrochemical nickel release testing was performed using a novel application of a radiotracer based method, thin layer activation (TLA). TLA was validated, in unstrained conditions, against adsorptive stripping voltammetry methodology. Control tests were also performed in non-fluoridated artificial saliva. From our research it transpired that the corrosion behaviour of Ni–Ti alloy is highly affected by the fluoride content, showing a release of 4.79 ± 0.10 μg/cm²/day, but, differently from other biomaterials, it does not seem to be affected by elastic tensile strain. The application of the TLA method in the biomedical field appears a suitable technique to monitor in real time the corrosion behaviour of biomedical devices.     

Extended treatment of primary osteoporosis by sodium fluoride combined with 25 hydroxycholecalciferol

Summary Nineteen patients suffering from primary osteoporosis, all having at least one vertebral collapse, initially received 50 mg of sodium fluoride alone per day for 6–18 months. Subsequently fluoride was associated with 25–50g of 25 OH cholecalciferol (calcifediol) per day for 6–18 months in 12 of these patients and 9 were treated for 31–58 months. As control group, 9 patients were given placebo for 6–18 months. The effect of the treatment was assessed by three methods: 1) the metacarpal index (MI) determined by radiogrammetry, 2) the calcium content of the hand bone (Ca) measured by local neutron activation, 3) the iliac bone histomorphometry. MI and (Ca) did not change significantly at any time in any group. In each group there was a significant increase in trabecular bone volume, osteoid volume, osteoid surfaces and a significant decrease in mineralization fronts. On the other hand, the changes in osteoblastic surfaces, osteoclastic surfaces, number of osteoclasts/mm2 were not significant in any group. No change was observed in the placebo group. These data suggest that the increase in the trabecular volume of fluorided bone is mainly due to the increase in osteoid which itself is due to a bone mineralization defect despite the association of calcifediol. This is probably one of the reasons why (Ca) does not change significantly.     

恩施市地方性氟中毒病区氟源初步调查

了解恩施市地方性氟中毒病区高氟来源,为地方性氟中毒病防治提供科学依据。方法：应用氟离子选择电极法分析新塘和红土两病区饮水、空气、煤及食物中氟含量。结果：饮水氟含量平均值为０．１６ｍｇ／Ｌ,低于国家饮用水氟标准;室内空气中氟含量平均值为 ０．０７８ｍｇ／ｍ３,超过国家空气氟标准;煤氟含量平均值为 ５３．９７ｍｇ／ｋｇ;食物氟水平普遍高于以燃柴为主的非氟病区,两病区属燃煤型地方性氟中毒病区。