Some public health effects of agricultural methane gas plants on the environment

Several big agricultural fermentation plants for producing of "biogas" are in operation in the GDR. Problems of distances to other objects, utilisation of methane and storage of liquid manure (slurry) are discussed. Some results of experiments about the immissions in the environment are demonstrated. They have point out, that the emissions of microorganisms and viruses cannot be demonstrated in a distance of more than about 200 meters. It is the most important hygienic acknowledge, that the distance of organoleptic observation is always greater than the epidemiologic or sanitary one. Therefore the production of energy by anaerobic fermentation of liquid manure and sewage sludge seems to be an useful way from hygienic point of view.     

镉对大鼠胰脏的毒作用

目的探讨镉对内分泌和外分泌功能的影响。方法将96只SD大鼠分为4组,分别为对照组和50、100、200mg/LCdCl2染毒组,饮水染毒30、60、90d。测定不同染毒时间大鼠血糖、尿糖、血胰岛素、淀粉酶的改变及血液中金属含量的改变;测定尿N-乙酰-β-D-氨基葡萄糖苷酶(NAG);并测定了胰脏组织中金属的含量以及胰脏金属硫蛋白基因、胰岛素基因和淀粉酶基因的表达情况。结果染毒组大鼠血糖水平在染毒90d的中、高剂量组有明显增加,差异有统计学意义(P<0.05),中剂量组血糖平均值为5.83mmol/L,高剂量组为6.46mmol/L;发现尿糖水平的增高先于尿NAG的增高。各剂量组大鼠血液和胰脏中镉的含量明显增加。在染毒90d中、高剂量组血锌含量降低。在染毒30d的中、高剂量组血液中胰岛素水平明显降低,而血淀粉酶改变不明显。在染毒90d的中、高剂量组胰脏组织中锌的含量明显增加。胰脏中金属硫蛋白基因表达均有不同程度的增加;胰岛素基因的表达除染毒60d中剂量组明显降低外,其他各组差异均无统计学意义(P>0.05)。而胰淀粉酶的基因表达在染毒60d和90d的中、高剂量组均明显增高。结论镉可以在胰脏组织蓄积,引起组织中必需元素锌水平的改变,导致基因和蛋白表达的改变,进一步引起胰脏内、外分泌功能的改变。     

Sublethal effects of cadmium ingestion on mallard ducks

Juvenile mallard (Anas platyrhynchos) drakes were fed diets containing 0, 50, 150, or 450 ppm cadmium for 42±1 days in order to assess the impacts of cadmium ingestion on energy metabolism and tissue metal concentrations in this species. Most significant (p<0.05) effects on energy metabolism were observed only in the 450 ppm group which displayed reduced body and liver weights, increased kidney weights, reduced liver aldolase activity, increased plasma concentrations of uric acid, decreased plasma triiodothyronine concentrations, and elevated adrenal weights and adrenal corticosterone concentrations. Ducks in the 150 ppm group displayed increased adrenal and kidney weights and elevated plasma nonesterified fatty acid concentrations. Among all treatments, increased cadmium and zinc concentrations in both livers and kidneys were dose-related; a similar trend was observed for copper concentrations in kidneys but not livers. Cadmium interference with carbohydrate metabolism in similar studies with mammals was more severe than that observed in mallards in the present study.     

镉对去卵巢大鼠肾脏的类雌激素作用

目的观察镉染毒对去卵巢大鼠肾脏中雌激素受体α(ERα)、雌激素受体β(ERβ)表达的影响。方法将24只健康12周龄SPF级SD雌性大鼠随机分为3组,分别为假手术(蒸馏水)组、去卵巢(蒸馏水)组、染镉(200 mg/L)去卵巢组,每组8只。假手术组切除小块卵巢周围的脂肪,去卵巢组和染镉去卵巢组切除双侧卵巢。术后1周,采用自由饮水方式进行染毒,连续染毒12周。采用电感耦合等离子体质谱法测定大鼠血镉、尿镉水平,采用酶联免疫吸附测定血清雌二醇、β2-微球蛋白水平,采用Western blot技术检测肾脏组织中ERα、ERβ蛋白的表达水平。结果与假手术组相比,去卵巢组染镉组12周末体重下降(P0.05)、肾脏系数升高(P0.05),去卵巢组及染镉去卵巢组雌激素水平降低(P0.05);与去卵巢组相比,染镉去卵巢组体重、雌激素水平降低(P0.05),肾脏系数、β2-微球蛋白、尿镉及血镉水平升高(P0.05);染镉去卵巢组血镉与尿镉、β2-微球蛋白、肾脏ERβ的表达水平正相关(P0.05),而与ERα无统计学相关性(P0.05)。结论重金属镉可降低去卵巢大鼠血清雌激素水平及增加雌激素受体β受体表达,这可能是镉的肾毒性作用机制之一。     

Renal effects of cadmium exposure in cadmium nonpolluted areas in Japan

Long-term exposure to cadmium (Cd) causes renal damage in the general population. The maximum allowable urinary Cd concentration, which was calculated from our previous study performed in a Cd-polluted area, was almost the same as the mean urinary Cd concentration of people living in nonpolluted areas. We assessed whether environmental Cd exposure is related to renal dysfunction of people in nonpolluted areas in Japan. Blood and urine samples were collected from 2753 subjects (1105 men and 1648 women) ages over 50 years old in three nonpolluted areas. Blood was analyzed for Cd and urine was analyzed for Cd, total protein, beta(2)-microglobulin (beta(2)-mg), and N-acetyl-beta-D-glucosaminidase (NAG). Cd in blood or urine was employed as indicators of internal dose; and urinary total protein, beta(2)-mg, and NAG were used as an indicator of renal dysfunction. Multiple regression analysis and logistic regression analysis were performed to clarify the dose-effect and dose-response relationship between blood or urinary Cd concentration and indicators of renal dysfunction. Multiple regression analysis demonstrated a significant dose-effect relationship between Cd in blood and urine and indicators of renal dysfunction. Logistic regression analysis also showed that the probability that individual subjects would have abnormal values of the renal variables was significantly related to Cd in blood and urine.     

镉对肠道功能影响的研究进展

目的 综述镉肠道毒性及其毒作用机制,为镉的肠道毒性与人体疾病关系的研究提供理论依据。方法 以“镉”、“肠道”、“微生物”、“益生菌”作为CNKI数据库、维普数据库和万方数据库检索词,以“Cadmium”、“Cd”、“Gut”、“Gastrointestinal Microbiome”、“Intestine”、“Bowel”、“Microorganism”作为PubMed数据库的检索词,参考文献56篇。结果 镉对肠道功能的毒性影响有两个方面:一方面镉影响肠道生理功能和结构,导致肠壁细胞通透性增加和组织结构破坏;另一方面镉引起肠道微生物数量和菌群多样性的改变、脂多糖产生增加和屏障功能受损,从而导致机体内毒素血症和全身炎症。结论 镉对肠道功能的毒性作用与人体健康和疾病的发生、发展密切相关,未来还需要更深入的研究去阐释镉对肠道功能影响的作用机制。     

The effects of low environmental cadmium exposure on bone density

Recent epidemiological data indicate that low environmental exposure to cadmium, as shown by cadmium body burden (Cd-U), is associated with renal dysfunction as well as an increased risk of cadmium-induced bone disorders. The present study was designed to assess the effects of low environmental cadmium exposure, at the level sufficient to induce kidney damage, on bone metabolism and mineral density (BMD). The project was conducted in the area contaminated with cadmium, nearby a zinc smelter located in the region of Poland where heavy industry prevails. The study population comprised 170 women (mean age=39.7; 18-70 years) and 100 men (mean age=31.9; 18-76 years). Urinary and blood cadmium and the markers of renal tubular dysfunction (β₂M-U RBP, NAG), glomerular dysfunction (Alb-U and β₂M-S) and bone metabolism markers (BAP-S, CTX-S) as well as forearm BMD, were measured. The results of this study based on simple dose-effect analysis showed the relationship between increasing cadmium concentrations and an increased excretion of renal dysfunction markers and decreasing bone density. However, the results of the multivariate analysis did not indicate the association between exposure to cadmium and decrease in bone density. They showed that the most important factors that have impact on bone density are body weight and age in the female subjects and body weight and calcium excretion in males. Our investigation revealed that the excretion of low molecular weight proteins occurred at a lower level of cadmium exposure than the possible loss of bone mass. It seems that renal tubular markers are the most sensitive and significant indicators of early health effects of cadmium intoxication in the general population. The correlation of urinary cadmium concentration with markers of kidney dysfunction was observed in the absence of significant correlations with bone effects. Our findings did not indicate any effects of environmental cadmium exposure on bone density.     

婴幼儿血镉含量对细胞因子损伤的影响

目的 研究婴幼儿血镉含量对体内细胞因子的影响.方法 收集48名婴幼儿静脉血,采用原子吸收光谱仪测定血镉的含量,双抗体夹心ABC-ELISA法测定白细胞介素1β浓度.按其血镉水平分为正常组、低镉组、高镉组.结果 白细胞介素1β含量在正常组为22.18±8.70pg/mL,低镉组和高镉组中分别为18.32±7.90pg/mL、12.79±7.10pg/mL,与正常组相比,低镉组白细胞介素1β浓度低于血镉正常组,但未达到显著性差异,P＞0.05,而高镉组则显著低于血镉正常组,P＜0.05,并与血镉浓度呈显著负相关(r=-0.42,P＜0.01).结论 血液中白细胞介素1β含量的变化可作为临床上判断婴幼儿期镉损伤的重要指标之一.     

Cytological effects of Tc on young soybean plants

Soybean seedlings (Glycine max cv. Williams) were exposed for 24 to 67 h to 99TcO4- (Tc) at various concentrations in dilute culture solution. Reduced primary leaf midrib length was observed with 67-h exposures to greater than or equal to 6.0 mu M Tc. Cellular effects were consistently observed by a light microscope after 43-h or longer exposure to 6.6 microM Tc and higher concentrations. At lower Tc levels, abnormal cells were interspersed among cells of normal appearance. Abnormal cells displayed blockshaped nuclei which were more densely stained by Harris' hematoxylineosin Y than controls; such cells frequently demonstrated incipient plasmolysis. The number of affected cells increased with dose; both nuclei and cytoplasm demonstrated greater staining intensity and more severe plasmolysis at higher levels. At levels of greater than or equal to 13.2 Tc, cellular damage was extensive. Cells were reduced in size and were highly plasmolysed; cell walls were distorted, and intercellular spaces were reduced or became nonexistent. Mitotic activity was observed at Tc levels less than or equal to 9.9 microM. Observed Tc cellular effects are attributed principally to the alteration of membrane permeability characteristics.     

职业接触镉对工人胰岛素水平的影响

目的研究镉对职业暴露人群胰岛素和血糖水平的影响。方法以我国中南地区某冶炼厂98名镉作业工人为职业接触对象,同时选取该厂职工医院未接触镉的健康医生作为对照。按照研究对象镉接触工龄及血镉、尿镉分组,调查了不同接触工龄组及不同血镉、尿镉组工人血清胰岛素水平的变化,同时检测机体血锌、尿锌水平的改变,并就血镉、血锌及血胰岛素等水平之间的相关关系进行分析。结果接触工龄20-年组血糖水平[(4．9±0．6)mmol／L]明显高于对照组[(4．6±0．5) mmol／L],差异有统计学意义(P<0．01)。接触工龄10～年组血清胰岛素水平[(8．58±4．91)μIU/ml]明显低于对照组[(11．57±5．42)μIU/ml],差异有统计学意义(P<0．05);且随血镉、尿镉水平的增加,血清胰岛素水平明显降低。接触工龄20-年者尿锌水平明显增高。相关分析显示,胰岛素与血镉、尿镉呈明显的负相关关系,血糖与胰岛素、C肽水平之间呈正相关关系。结论职业接触镉可以导致血清胰岛素水平的降低,可能影响血糖水平。     

Phytoremediation of cadmium contamination: Overexpression of metallotionein in transgenic tobacco plants

Summary The contamination of heavy metals by mining and combustion of fossil fuel has brought about significant deleterious consequences not only to environment but also to human health. Cadmium is a potentially toxic metal which causes renal dysfunction, pulmonary emphysema, and possibly bone demineralization. To explore the potential of plants to tolerate this metal, we engineered a model plant, Nicotiana tabacum, to express a metallothionein under the control of CaMV 35S promoter. Transgenic plants expressing metallothionein were able to grow in concentrations of up to 200 μM CdSO₄. Nontransgenic plants promptly underwent leaf chlorosis and their growth and development were inhibited on the medium containing 50 μM CdSO₄. PCR analysis for CdSO₄ from sensitive and resistant T₂ seedlings confirmed a high correlation between increased Cd-tolerance and the transgenic genotype, indicating that cadmiun resistance is stably inherited in the next generation. This result suggests one possible strategy for phytoremediation of heavy metals by expression of plant MT.     

氯丙嗪和异搏定对镉毒性的拮抗作用

目的 探讨氯丙嗪（Chlorpromazine，CPZ）和异搏定（Verapamil，Ver）对镉毒性的影响。方法 32只Wis—tar大鼠随机分成4组：对照组、单纯染镉组、氯丙嗪及异搏定干预组。测定肝和肾皮质镉、丙二醛（MDA）、谷胱甘肽（GSH）含量和谷胱甘肽过氧化物酶（GSH-Px）、超氧化物歧化酶（SOD）活性以及尿N-乙酰-β-D氨基葡萄糖苷酶（NAG）和碱性磷酸酶（ALP）活性。结果 单纯染镉组肝、肾皮质MDA、GSH含量和尿NAG和ALP活性显著高于对照组，而。肾皮质SOD活性显著低于对照组。CPZ干预组肝和。肾皮质MDA含量分别为单纯染镉组的75％，78％；肾皮质GSH含量显著低于单纯染镉组，而GSH-Px和SOD活性显著高于对照组和单纯染镉组。Ver干预组肝、肾皮质MDA和肾皮质GSH含量显著低于单纯染镉组，而肾皮质GSH-Px活性显著高于对照组，肾皮质SOD活性显著高于单纯染镉组。2个干预组尿NAG活性显著低于单纯染镉组。结论 CPZ和Ver对镉毒性具有一定的拮抗作用。     

Longitudinal studies on the health effects of exposure to environmental cadmium

Renal damage induced by cadmium (Cd) results in a proximal renal tubular dysfunction, characterized by low-molecular weight (LMW) proteinuria, renal glucosuria, generalized aminoaciduria and decreased renal tubular reabsorption of uric acid and phosphate. Since LMW proteinuria is thought to be one of the earliest adverse health effects caused by Cd, the prevention of the progress of LMW proteinuria is important to avoid further deteriorations in the health condition. Follow-up studies on residents in Cd-polluted areas and Cd-exposed workers have indicated that Cd-induced LMW proteinuria is generally irreversible and progressive even after the cessation or reduction of exposure. The intensity of exposure and the body burden of Cd before the reduction of exposure may influence the prognosis of Cd-induced LMW proteinuria. Several studies have reported a gradual decline in the glomerular filtration rate even after the reduction of Cd exposure. Cohort studies performed in Cd-polluted areas of Japan showed that renal tubular dysfunction and a decreased glomerular filtration rate were strongly associated with increased risk of mortality. However, the results also suggested that overall mortality rates in Cd-polluted areas were not necessarily increased, because of the low mortality among those with urinary beta 2-microglobulin concentrations < 1,000 micrograms/g creatinine. At present, incidence data are too limited to draw a conclusion regarding the cancer risk among residents in Cd-polluted areas.