A contribution to the establishment of reference values for total mercury levels in hair and fish in amazonia

Studies on mercury levels in the Amazonian Region have typically lacked background or reference parameters. A sectional study on Hg concentration in hair and fish was conducted, together with an assessment of the prevalence of signs and symptoms related to Hg poisoning, in four communities in the Amazon Basin not impacted by gold mining, located either by a river course (Santana do Ituqui and Caxiuan?) or by a lake (Aldeia do Lago Grande and Vila do Tabatinga). Mercury determinations in hair and fish were made by flameless atomic absorption spectrophotometry. Mean total Hg in hair was 4.33 microg/g (0.40-11.60 microg/g) in 321 individuals from Santana do Ituqui, 3.98 microg/g (0.40-11.76 microg/g) for 316 persons in Aldeia do Lago Grande, 5.46 microg/g (0.37-49.85 microg/g) for 504 individuals from Vila do Tabatinga and 8.58 microg/g (0.61-45.59 microg/g) for 203 inhabitants from Caxiuan?. Fish consumption was very high in all those communities but no signs or symptoms associated with Hg poisoning were found. Mean Hg concentration in fish varied from 0.006 to 2.529 microg/g for carnivores and from 0.008 to 0.871 microg/g for noncarnivores. These values suggest that further studies including a larger number of communities would eventually lead to values of "normal" Hg concentration in the Amazonian Region quite above the limits suggested by the World Health Organization.     

Mercury exposure in Munduruku Indians from the community of Sai Cinza,State of Pará, Brazil

The objective of this cross-sectional study was to evaluate mercury exposure and health status among Munduruku Indians from the community of Sai Cinza, State of Pará, Brazil. The population studied included 330 indians, who submitted to a questionnaire, clinical exams, and collection of hair, blood, urine, and feces. Mercury was measured in hair and fish. Although no person was found to have overt mercury intoxication, the mean levels of mercury in hair were elevated (14.45 micrograms/g for children from 7 to 12 years old, 15.70 micrograms/g for women between 14 and 44 years old, and 14.1 micrograms/g for the remaining population). Mercury levels in fish were below levels recommended by the World Health Organization, but rates of fish consumption were high. These results place this indigenous populations as a group under risk of mercury toxicity from the gold production.     

Exposure to metallic gold in patients with contact allergy to gold sodium thiosulfate

Gold allergy is common, with approximately 10% of patients patch tested because of eczematous disease being positive to gold sodium thiosulfate (GSTS). However, clinical relevance seems to be rare. The aim of this prospective double-blind study was to demonstrate the effects of exposure to metallic gold, in this case earrings, in gold-positive patients. 60 female patients with pierced earlobes test-positive to GSTS were included in the study. The patients were randomized into 2 groups, 30 patients receiving earrings with a surface layer consisting of 24-carat gold and 30 patients earrings with a surface layer of titanium nitride, virtually indistinguishable from gold. The patients wore the earrings for 8 weeks. During the study, any dermatitis on the earlobes, as well as on other body sites, was registered. The skin reactions observed were weak but, in total, 17 of the 60 patients had a skin reaction (local or remote) during the study, 12 of whom had received gold earrings and 5 titanium (p<0.05). 11 patients had a reaction on the earlobes, 7 of whom had received gold earrings and 4 titanium (NS). With these facts it is hard to exclude that exposure to gold jewelry can be clinically relevant in persons hypersensitive to gold.     

人血清痕量金涂钒石墨管-石墨炉原子吸收光谱法测定

目的:建立人血清中痕量金的准确、灵敏的测定方法.方法:金与硫代米蚩酮在酸性介质中生成稳定的络合物,用异戊醇萃取后,取有机相直接进样,采用涂钒热解石墨管,石墨炉原子吸收法测定痕量金.结果:该方法的检出限为1.8×10-12g.回收率在92.6%～103.5%.对于10μg/L金的测定表明,该方法的相对标准偏差为2.9%.结论:该方法用于人血清中痕量金的测定结果满意.     

疑难疾病中医论治时被忽略的两点思路

中医治疗疑难疾病时，往往忽略了两个重要因素：一是患者的五运六气体质结构；二对人体的太极气化结构及天人合一太极共振了解不足。在治疗疑难疾病时，应该综合考虑天人合一、五运六气理论，结合天人合一太极共振扶正，可能从更深层次调动人体的自我修复系统。     

包埋料和热处理对自研贵金属合金铸造适合性的影响

目的　比较不同包埋料和热处理方法对牙科铸造贵金属合金BS 1金合金铸件铸造适合性的影响。方法　采用 2种包埋料 (F 1和Z 1包埋料 )包埋模拟后牙冠的帽状代型蜡型 ,用BS 1金合金铸造 ,铸件经过不同的热处理 (软化热处理 ,硬化热处理和恒温时效硬化热处理 )后试合于各自的石膏代型 ,在体视显微镜和金相显微镜下分别测试铸件的边缘适合性和组织面密合度 ,求各自的平均值 ,统计分析各组之间的统计学差异性。结果　F 1包埋料组的边缘差异明显小于Z 1包埋料组 (P <0 0 5 )。热处理对金合金铸件的铸造适合性无显著性影响。结论　BS 1金合金用F 1包埋料包埋铸造的铸件其铸造适合性优于Z 1包埋料组。热处理对其铸造适合性无显著性影响     

含金矿物的氰化浸取动力学

筛选了一种能强化金浸取反应速率的添加剂——间硝基苯磺酸钠(MS),并进行了浸取反应过程的动力学研究。讨论了MS和氰化钠浓度、温度、搅拌强度及矿物粒度等因素对浸取反应的影响。MS通过改变阴极反应体系强化了金的氰化浸取反应速率,且对浸取液中氰化物无破坏作用。采用收缩未反应芯模型较好地描述了金的浸取过程,金浸取的动力学过程受扩散控制。同时导出了宏观动力学方程。用黄铁矿焙渣在串联式池浸装置中进行工业化模拟试验的结果表明,含MS的浸取液,浸取金含量仅为0.94g/t的矿渣,具有较力满意的结果。     

Comparison of the effect of amphotericin B desoxycholate and amphotericin B colloidal dispersion on renal functions and renal morphology in rats

BACKGROUND AND AIM: Amphotericin B (AmB) desoxycholate remains as one of the most efficacious agents currently available for the treatment of systemic fungal infections; however, amphotericin B colloidal dispersion (ABCD) has been developed because of AmB desoxycholate nephrotoxicity. The goal of our study was to compare the effect of administration of AmB desoxycholate and ABCD on renal functions and renal morphology in rats. RESULTS: Amophotericin B desoxycholate as well as ABCD causes damage to renal tubuli and polyuria. Amophotericin desoxycholate causes considerably more severe damage to tubuli than ABCD, but the morphological damage to renal glomeruli is minimal in both formulas. In tubular cells, AmB desoxycholate causes severe damage to mitochondria, vacuolation of cytoplasm, and increased values of volume density of peroxisomes. CONCLUSION: None of these formulas causes a decrease in glomerular filtration in rats when animals are properly hydrated.     

Percutaneous absorption of gold sodium thiosulfate used for patch testing

Contact allergy to gold has been shown to be correlated to wearing of golden jewellery as well as to the presence of dental gold. The prerequisite for sensitization and elicitation of an allergic contact dermatitis to gold is ionization and percutaneous absorption of the allergen. The present study was undertaken with the aim to demonstrate gold in blood after an occlusive patch testing with gold sodium thiosulfate (GSTS). Patients were patch tested with GSTS 0.5, 2.0 and 5.0% in petrolatum. Venous blood was sampled before testing as well as on day 3 (D3) or day 7 (D7). Blood gold levels were analysed by inductively coupled plasma mass spectrometry. In all 66 patients, the blood level of gold was significantly higher in the 2nd blood sample than in the 1st (median 0.34 versus 0.03 micro g/l). The increase was similar in patients allergic and not allergic to gold. There was no difference between gold levels on D3 and on D7 after epicutaneous application. Presumably, other allergens may also be taken up in blood during patch testing.