Morphometric study of bone in domestic pigs with fluorosis caused by coal-burning pollution

Forty four domestic pigs were divided into 2 groups: control group: 17 pigs; fluorosis group: 27. They were fed for 14 months in the endemic area or non-endemic area respectively. In some of the pigs, double tetracycline was given for bone dynamic study, and blood and urine were collected for biochemical analyses. Iliac, tibia, fibula, the 2nd metatarsal and the 2nd vertebrae were reserved either for bone density measurement or for bone histomorphometric study. The results showed that fluoride content either in serum and in urine or in bone tissue was significantly elevated. The bone density of tibia was increased. Bone histomorphometry showed that trabecular bone volume of iliac and vertebrae was increased while that of fibula head was decreased. Trabecular resorption surface of fibula head was expanded while that of vertebrae was shrunk. As to bone dynamics, both bone formation rate and bone mineralization rate were inhibited, indicating that the toxic effects of fluoride in tremendous amount on bone remodeling. The authors suggest that the existence of osteosclerosis of axial and osteoporosis of peripheral bone in fluorosis might be related to the redistribution of calcium within the body. Furthermore, fluoride may be an osteomalacic factor for the development of osteomalacia in endemic fluorosis.     

IS THE SEVERITY OF OSTEOSCLEROSIS OF FLUOROSIS PROPORTIONAL TO THE DOSE OF FLUORIDE INTAKE?

Histomorphometric study was made on a series of sections of undecalcified epiphyseal femoral specimens from rats with experimental fluorosis. The results revealed osteosclerosis in Group A (5 ppm) being more severe than that in Group B (25 ppm) With the increase of fluoride dose, the parameters fell down instead of increased in parallel. There is seemingly a threshold over which osteosclerosis in fluorosis becomes less severe. In contrast to Bely's conclusion the authors proposed that, fluoride toxi- city, besides decreasing the number of osteoblasts, may also activate the osteoblasts. The number of osteoblasts may be increased with relative lower dose of fluoride also. The net outcome is the in crement in bone volume. When toxic dose of fluoride is higher enough (higher than the proposed threshold), however, the number of osteoblasts and its activity are inhibited. So are the osteocytes. This interpretation may be the cytological basis for osteosclerosis in the experimental fluorosis.     

氟铝联合作用时氟与不同种类铝化合物在代谢中相互作用的差异

59只兔随机分为对照、氟组、低铝氟组和高铝氟组。经14周亚慢性毒性实验,发现氟和铝在吸收、蓄积及排泄中均产生相互作用,并对Fe、Ca、P等元素产生影响。对照组骨灰铝为43.11ppm,氟组为83.13ppm,低铝氟组为52.45ppm,高铝氟组为32.33ppm。表明氟能促进饲料中本底铝在骨中蓄积,硫酸铝能拮抗这种作用。作者认为铝在氟中毒骨骼病变中有重要作用。     

郴州市地方性氟中毒改水降氟监测结果分析

目的　了解郴州市地方性氟中毒改水降氟效果 ,以及改水设施的管理和使用情况。方法　对郴州市所辖两个自然村的饮水氟含量、儿童氟斑牙患病率和成人氟骨症患病率进行了监测。结果　改水后两个自然村饮水氟含量分别为 0 .15mg/L和 0 .0 3mg L ;氟斑牙患病率分别为 4 2 .35 %和 31.2 5 % ,氟骨症患病率 2 4 .0 %和 2 8.3%。但由于人口增加 ,改水设施管理使用不善 ,致使居民中约 5 0 %的饮用水源未经改水降氟。结论　改水降氟后 ,保证饮用低氟水是防制此病的关键。     

抗氟灵冲剂对实验性氟损伤治疗与预防作用研究

通过大鼠实验研究,观察了“抗氟灵”冲剂对氟损伤治疗和预防作用。结果表明:氟中毒大鼠的尿氟、骨氟、牙氟及碱性磷酸酶（AKP）活性均明显增高,而血清超氧化物歧化酶（SOD）活性降低。“抗氟灵”能以氟硼酸根离子形式增加氟的排出,阻止氟转移到靶器官骨、牙组织.从而防止骨及牙氟增高和AKP活性升高。对氟中毒的大鼠,“抗氟灵”亦能降低骨及牙氟浓度和AKP活性,恢复SOD活性。其机理是“抗氟灵”以BF_4-形式增加尿F-排出,并有一定提高机体抗氟功能。     

食盐氟的研究

本文以选择性离子电极加入法对市售19个样本中氟化物含量进行了测定,发现其含量与品种及加工过程有关,海盐与井盐含氟量在2.32～2.82ppm;矿盐与湖盐含氟量为1.14～1.98ppm,粗盐含氟量比精盐高1.19～1.39倍,经计算从食盐摄入的氟量占总摄入氟量的1.47～2.00％,作者建议在农村低氟地区可通过食盐加氟达到防龋的目的。     

Bilateral fractures of femoral neck in patients with moderate renal failure receiving fluoride for spinal osteoporosis

Two patients with moderate renal failure sustained spontaneous bilateral hip fractures during treatment with fluoride, calcium, and vitamin D for osteoporosis. They had been taking sodium fluoride (40-60 mg/day) for 11 and 21 months, respectively. Histological examination of a specimen of the bone showed severe fluorosis in the first case, and quantitative analysis of bone showed osteomalacia and skeletal fluorosis in the other case. These abnormalities were considered to be the consequence of excessive retention of fluoride due to renal insufficiency. As bilateral femoral neck fractures are very rare these data suggest a causal link between fractures and fluoride in patients with renal failure. Thus fluoride should be given at a lower dosage, if at all, to patients with even mild renal failure.     

Appropriate uses of fluorides for children: guidelines from the Canadian Workshop on the Evaluation of Current Recommendations Concerning Fluorides.

OBJECTIVE: To prevent fluorosis caused by excessive fluoride ingestion by revising recommendations for fluoride intake by children. OPTIONS: Limiting fluoride ingestion from fluoridated water, fluoride supplements and fluoride dentifrices. OUTCOMES: Reduction in the prevalence of dental fluorosis and continued prevention of dental caries. EVIDENCE: Before the workshop, experts prepared comprehensive literature reviews of fluoride therapies, fluoride ingestion and the prevalence and causes of dental fluorosis. The papers, which were peer-reviewed, revised and circulated to the workshop participants, formed the basis of the workshop discussions. VALUES: Recommendations to limit fluoride intake were vigorously debated before being adopted as the consensus opinion of the workshop group. BENEFITS, HARMS AND COSTS: Decrease in the prevalence of dental fluorosis with continuing preventive effects of fluoride use. The only significant cost would be in preparing new, low-concentration fluoride products for distribution. RECOMMENDATIONS: Fluoride supplementation should be limited to children 3 years of age and older in areas where there is less than 0.3 ppm of fluoride in the water supply. Children in all areas should use only a "pea-sized" amount of fluoride dentifrice no more than twice daily under the supervision of an adult. VALIDATION: These recommendations are almost identical to changes to recommendations for the use of fluoride supplements recently proposed by a group of European countries. SPONSORS: The workshop was organized by Dr. D. Christopher Clark, of the University of British Columbia, and Drs. Hardy Limeback and Ralph C. Burgess, of the University of Toronto, and funded by Proctor and Gamble Inc., Toronto, the Medical Research Council of Canada and Health Canada (formerly the Department of National Health and Welfare). The recommendations were formally adopted by the Canadian Dental Association in April 1993.     

氟对大鼠骨ROS和RNA含量的影响

目的 :探讨饮用氟水大鼠骨RNA和ROS的含量变化在氟骨症早期发病机理中的作用。方法 :Wistar大鼠80只 ,雌、雄各半 ,平均体重为 90 g± 5 g。随机分成 4组 ,用试剂盒测定血清中丙二醛 (MDA)及骨组织中的RNA的含量。用ESR检测骨ROS的含量。结果 :低、中、高氟组骨ROS及血清中MDA含量变化含量均有所升高 (F =3.98,P <0 .0 1) ,骨中RNA含量随氟剂量的增加而逐渐减少。结论 :提示饮用水中的氟含量会影响体内脂质过氧化物水平升高降低 ,从而影响骨合成RNA的能力     

维生素C、E对氟中毒大鼠尿氟排泄的影响

目的：观察氟中毒大鼠尿氟排泄情况,探讨维生素C、E不同剂量以及单独和/或联合使用对氟中毒大鼠尿氟排泄的影响.方法：将90只Wistar大鼠随机分为9组,每组10只,经饮水投氟建立氟中毒动物模型,并通过灌胃补充维生素C、E,分别于实验第5周、第10周和第15周收集24 h尿液,采用氟离子选择性电极法测定尿氟含量.定期称体重,观察大鼠体重的变化.结果： 随着染毒时间的延长大鼠尿氟的排出量逐渐增加,尿氟含量在染毒第15周＞第10周＞第5周（P＜0.05）.补充维生素C和/或维生素E均可使大鼠尿氟含量显著增加.维生素C、E不同剂量组之间尿氟含量也有所不同,随着干预剂量的增加尿氟含量减少.结论：给予维生素C、E对氟中毒大鼠氟代谢有显著作用,可促进尿氟的排泄,阻断氟的吸收.维生素C、E在一定剂量范围内可拮抗氟的毒性作用,减轻氟中毒病情.