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排序方式: 共有2508条查询结果,搜索用时 375 毫秒
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Jim-Shoung Lai T.-N. Wu Saou-Hsing Liou Chen-Yang Shen Chiam-Fang Guu Kquei-Nu Ko Chi. Hsueh-Yun P.-Y. Chang 《International archives of occupational and environmental health》1997,69(4):295-300
Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship
between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were
measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics
and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear
regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol
consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although
PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based
on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient
lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood
lead levels in lead battery factories.
Received: 28 May 1996/Accepted: 30 August 1996 相似文献
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W T Yuh E T Tali H D Nguyen T M Simonson N A Mayr D J Fisher 《AJNR. American journal of neuroradiology》1995,16(2):373
PURPOSETo evaluate the effect of MR contrast dose versus delayed imaging time on the detection of metastatic brain lesions based on lesion size.METHODSContrast MR examinations with gadoteridol were obtained in 45 patients with brain metastases. The patients were divided into two groups: 16 received cumulative standard dose (0.1 mmol/kg) and 29 received cumulative triple dose (0.3 mmol/kg). Both groups were evaluated at two dose levels (lower dose and higher dose) with two separate injections. Each patient received an initial bolus injection of either 0.05 (cumulative standard dose) or 0.1 (cumulative triple dose) mmol/kg of gadoteridol to reach the lower-dose level and underwent imaging immediately and 10 and 20 minutes later. Thirty minutes after injection, an additional bolus injection of 0.05 (cumulative standard dose) or 0.2 (cumulative triple dose) mmol/kg was administered to reach the cumulative higher-dose level (cumulative standard dose, 0.1 mmol/kg; cumulative triple dose, 0.3 mmol). Images were acquired immediately.RESULTSThere was no difference in the detection rate for lesions larger than 10 mm among T2-weighted, lower-dose immediate and delayed, or immediate higher-dose images in both study groups. Lesions smaller than 10 mm had improved detection with delayed imaging in both study groups; however, the immediate higher-dose studies still had the highest detection rate.CONCLUSIONIn the evaluation of small central nervous system metastases, either delayed imaging after the injection of standard contrast dose or higher contrast dose may improve their detection, and therefore affect clinical management. Higher contrast dose (cumulative triple dose) studies appear to be more effective than delayed imaging with standard dose. 相似文献
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T.-N. Wu Chen-Yang Shen Saou-Hsing Liou Guang-Yang Yang K.-N. Ko Show-Lin Chao Chao-Chun Hsu P.-Y. Chang 《International archives of occupational and environmental health》1997,69(6):386-391
To monitor the lead hazards in industries and to investigate the prevalence of elevated blood lead levels (BLLs) in lead-exposed
workers, a lead surveillance system (PRESS-BLLs) has been established and operated in Taiwan, Republic of China, since July
1993. A cohort of lead-exposed workers who received a periodic annual health examination at 55 accredited hospital laboratories
was constructed. A total of 9807 separate BLL measurements were reported to the system in 1994. The mean BLL was 15.8 μg/dl
in male workers and 11.6 μg/dl in female workers. The mean BLL of lead-exposed workers was significantly (P<0.05, z-test) higher than that of the general Taiwanese population (8.6 μg/dl for males and 6.7 μg/dl for females). In addition,
the BLLs of 983 (10.0%) workers exceeded the regulatory action level (40 μg/dl for males; 30 μg/dl for females). The workplaces
and homes of 57% of the workers with elevated BLLs were thoroughly investigated to determine the sources of lead contamination.
These actions identified the causes of elevated BLLs and set up strategies to reduce workers’ lead exposure. The establishment
of this occupational lead surveillance system represents a method for monitoring of lead hazards from occupational and environmental
settings to prevent lead poisoning. The information acquired from the system can help in the setting up of a priority of prevention
and the development of control measures. It is also useful for further monitoring of changes in the BLLs of the lead-exposed-worker
cohort. The Health Department of Taiwan can use this information to evaluate the effectiveness of current industrial hygiene
practice. Subjects with elevated BLLs have been medically treated and placed on long-term follow-up for sequelae.
Received: 2 September 1996/Accepted: 29 November 1996 相似文献
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Chih-Hsin Tang Rong-Sen Yang Houng-Chi Liou Wen-Mei Fu 《Journal of bone and mineral research》2003,18(3):502-511
The skeletal extracellular matrix produced by osteoblasts contains the glycoprotein fibronectin (Fn), which regulates the adhesion, differentiation, and function of osteoblasts. Fn fibrillogenesis is involved in the process of bone mineralization. Bone morphogenetic proteins (BMPs) can be isolated from organic bone matrix and are able to initiate de novo cartilage and bone formation. In this study, the effect of BMP-4 on Fn fibrillogenesis in cultured rat osteoblasts was examined. BMP-4 enhanced Fn synthesis and extracellular Fn assembly in primary cultured osteoblasts. In addition, the extracellular assembly of Fn from exogenously applied soluble human Fn was also increased by BMP-4. It has been reported that alpha5beta1 integrin is related to Fn fibrillogenesis. The synthesis of both alpha5 and beta1 integrins was upregulated by BMP-4. Immunocytochemistry showed that the clustering of alpha5 and beta1 integrins was also increased by BMP-4. BMP-4 increased fibril formation of Fn and the adhesion of osteoblasts onto Fn matrix, which was inhibited by disintegrin triflavin and Gly-Arg-Gly-Asp-Ser (GRGDS) peptide. Phosphorylation of extracellular signal-regulated kinase (ERK) and focal adhesion kinase (FAK) was increased by BMP-4. Enhancement of extracellular Fn fibrillogenesis and the mRNA expression of beta1 integrin by BMP-4 were inhibited by ERK kinase (MEK) inhibitor PD98059. These results suggest that the enhancement of extracellular Fn fibrillogenesis by BMP-4 in cultured osteoblasts is related to the increase of the synthesis of Fn and clustering of alpha5 and beta1 integrins. ERK is involved in the signaling pathway of BMP-4 in regulating Fn fibrillogenesis in osteoblasts. 相似文献
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The number, size, and location of cerebral infarctions, and blood flow in the middle cerebral artery as seen on proton magnetic resonance imaging were assessed in six white adults with angiographically documented moyamoya. Findings were correlated with clinical presentation, computed tomography, and angiography. Large hemispheric infarctions were found in five hemispheres, predominantly in watershed regions. Subcortical infarctions (n = 56) were found in all hemispheres. They were predominantly located in the centrum semiovale, in the distal beds of supply of the penetrating branches of the anterior and middle cerebral arteries. Infarction of the putamen was found in three hemispheres, caudate nucleus in four, globus pallidus in two, and anterior limb of the internal capsule in two. There were none in the posterior limb of the internal capsule, thalamus, brain stem, or cerebellum. Middle cerebral artery flow was visualized as a signal-void flow sign in only three hemispheres. Cerebral infarctions due to moyamoya are bilateral, multiple, often small, and asymptomatic, affecting predominantly the carotid circulation in watershed regions. Subcortical infarctions in the centrum semiovale and large hemispheric infarctions in hemodynamically compromised areas are the predominant findings. 相似文献
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A 61-year-old man experienced four bouts of pancreatitis in 1 year. Detailed history taking and a series of examinations, including sonography, computed tomography scan, and endoscopic retrograde cholangiopancreatography (ERCP), revealed pancreas divisum on the first admission. He was treated conservatively. However, repeated ERCP on the fourth admission, 1 year later, showed a small filling defect in the tail of the pancreatic duct. A distal pancreatectomy was carried out. Pathological studies revealed a small papillary adenocarcinoma (1.5 x 1.0 x 0.5 cm) confined to the pancreatic duct grossly with minimal parenchymal invasion microscopically. He has been free from cancer and pancreatitis for 13 months since the operation. 相似文献