Exploration on the reformation of epidemiology teaching mode for postgraduates / 中华流行病学杂志

Objective: To explore the suitable teaching mode of epidemiology for postgraduates, so as to provide techniques for improving and enhancing the teaching quality. Methods: The course was divided into three stages according to the teaching progress, which was, traditional teaching, traditional teaching and case discussion, online learning and case discussion. The test scores in three stages were compared respectively, and the students' willingness to teaching methods was investigated by questionnaire. Results: The scores of 214 students showed an upward trend in three stages, and the differences were statistically significant (P<0.001). Most students paid more attention to the knowledge systematization and important knowledge. Most students proposed that the teaching time between theoretical knowledge and case discussion should be evenly distributed. More students chose Chinese literature related to their major as teaching cases. Most students believed that case discussion improved the skills of self-study and communication. Conclusion: The epidemiology course for postgraduate should integrate the traditional teaching and case discussion, with online learning as a supplementary, and take effective methods to evaluate, so as to improve the teaching quality of postgraduate.

Risk assessment of nerve conduction velocity in workers exposed to lead / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the dose-effect relationship between lead exposure and nerve conduction velocity, and to assess risk characteristics of nerve conduction velocity induced by lead exposure.</p><p><b>METHODS</b>The external dose, internal dose (blood lead, urine lead) and the conduction velocity of peripheral nerve were examined. The benchmark dose of a population exposed to occupational lead was estimated to develop risk assessment of nerve conduction velocity in worker exposed to lead by use of BMDS (version 1.3.3). The BMDL in terms of blood lead and urine lead was calculated.</p><p><b>RESULTS</b>There was correlation between blood lead and urine lead. The sense nerve conduction velocity was decreased significantly in the group of lead exposure workers (P < 0.05). The BMDLs-05 for median nerve conduct velocity, ulnar nerve conduction velocity, and superficial peroneal nerve conduction velocity in terms of blood lead were 456.99, 332.36 and 468.38 microg/L respectively; the BMDLs-05 in terms of urine lead were 14.1, 9.2 and 13.6 microg/gCr respectively.</p><p><b>CONCLUSION</b>The internal dose is the better index to reflect the level of lead exposure. Blood lead is identified as a specific and sensitive biomarker for sense nerve conduction velocity reduction. Ulnar nerve conduction velocity can be used as highly sensitive biomarkers to screen the high risk population of lead exposure.</p>

Risk assessment of renal dysfunction caused by occupational lead exposure / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To assess the risk of renal dysfunction caused by occupational lead exposure through epidemiological investigation.</p><p><b>METHODS</b>The workers in a battery factory were selected as the subjects for the exposure and effect assessment. The occupational environmental monitoring data was collected and used to calculate the total external dose of lead. The relationship between external dose and internal dose of lead was analyzed. The external dose, blood lead (BPb) and urinary lead (UPb) were used as exposure biomarkers while the urinary N-acetyl-D-glucosaminidase (UNAG), and urinary albumin (UALB) were used as the effect biomarkers for the renal dysfunction caused by lead. Software of BMDS (BMDS 11311) was used to calculate BMD.</p><p><b>RESULTS</b>The external and internal does of lead was positively correlated (BPb: r = 0.466, P < 0.01; UPb: r = 0.383, P < 0.01). The levels of BPb, UPb in exposure group (654.03 microg/L, 143.45 microg/g Cr) were significantly higher than those in the control group (57.12 microg/L, 7.20 microg/g Cr), so were UALB, UNAG; in addition, all of them presented significant dose-response relationship. The BPb BMD of UALB, UNAG were 607.76, 362.56 microg/L respectively and the UPb BMD of UALB, UNAG were 117.79, 78.79 microg/gCr respectively.</p><p><b>CONCLUSION</b>Occupational lead exposure can cause renal dysfunction, which presents dose-response relationship; the risk assessment of renal dysfunction caused by occupational lead exposure is performed by BMD calculation of BPb and UPb.</p>

Effects of occupational lead exposure on lumbar vertebral fracture in male workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of occupational lead exposure on lumbar vertebral fracture in exposed male workers.</p><p><b>METHODS</b>One hundred and fifty-two lead-exposed male workers in a storage battery plant in Shanghai were selected as the study population. The blood lead (BPb) and the urinary lead (UPb) were measured by graphite-furnace atomic absorption spectrometry (GF-AAS). Bone mineral density (BMD) was measured by the monophoton absorptiometry(SPA-4) and Z score was determined. Anteroposterior and lateral lumbar spinal X-ray films were taken to determine lumbar vertebral fracture.</p><p><b>RESULTS</b>For the occupationally lead-exposed workers, geometric mean of BPb was 0.85 (0.33 approximately 1.90) micromol/L, geometric mean of UPb was 4.84 (0.46 approximately 21.31) microg/g Cr, and the prevalence of lumbar vertebral fracture was 19.7%. The prevalence of lumbar vertebral fracture would increase with the increase of age and work year, but with no significantly statistical difference (P > 0.05). The bone mineral density (BMD) would decrease with the increase of BPb and UPb (P < 0.05). The prevalence of lumbar vertebral fracture would increase significantly with the increase of the lead exposure (P < 0.05) with the linear correlation (P < 0.05). The prevalence of lumbar vertebral fracture would increase significantly with the decrease of the bone mass (P < 0.01) with the linear correlation (P < 0.01).</p><p><b>CONCLUSION</b>The occupational exposure to lead could cause the decrease of the bone mineral density and the increase of the prevalence of lumbar vertebral fracture. The development of lumbar vertebral fracture is associated with the decrease of bone mass.</p>

Insulin expression in rats exposed to cadmium / 生物医学与环境科学（英文）

<p><b>OBJECTIVES</b>To investigate the effects of cadmium exposure on insulin expression in rats.</p><p><b>METHODS</b>Eighteen adult SD rats were administered cadmium subcutaneously (0.5, 1.0, and 2.0 mg/kg x bw). The effects on endocrine of pancreas were assessed. The levels of cadmium and zinc in pancreas, blood and urine glucose, serum insulin and urine NAG (N-acyetyl-beta-glucosaminidase) were determined. The gene expressions of metallothionein (MT) and insulin were also measured, and the oral glucose tolerance tests (OGTT) were carried out.</p><p><b>RESULTS</b>The contents of cadmium in pancreas in cadmium-treated rats were higher than that in the control group, which was associated with slight increase of zinc in pancreas. Cadmium-exposed rats (1.0 and 2.0 mg/kg x bw) demonstrated a marked glucose intolerance. But the levels of serum insulin did not change significantly after cadmium administration, and the UNAG had no change in Cd-treated group. The gene expression of insulin decreased in 1.0 and 2.0 mg/kg x bw cadmium-exposed groups, compared with the control group. The expression of MT-I was higher in the groups exposed to 1.0 and 2.0 mg/kg x bw cadmium while the expression of MT-II was higher in the group exposed to 2.0 mg/kg x bw cadmium.</p><p><b>CONCLUSIONS</b>Cadmium may be accumulated in the pancreas, resulting in the change of the expression of insulin, MT-I and MT-II genes. Cadmium can influence the biosynthesis of insulin, but does not induce the release of insulin. The dysfunction of pancreas occurs earlier than that of kidney after administration of cadmium.</p>

Effects of occupational lead exposure on bone mineral density and bone metabolism in workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of occupational lead exposure on the bone mineral density and the bone metabolism in exposed workers.</p><p><b>METHODS</b>Two hundred and ninety-eight lead-exposed workers in a storage battery plant in Shanghai were selected as the exposed subjects while eighty-one healthy officers in the plant who were not occupationally exposed to lead were treated as the control. The blood lead (BPb) and the urinary lead (UPb) were used as the exposure biomarkers while the Z score, the urinary hydroxyproline (HYP) the serum alkaline phosphatase (ALP) the serum alkaline phosphatase bone isoenzyme BALP and the serum osteocalcin BGP were used as the effect biomarkers for the bone effect caused by the lead. Bone mineral density (BMD) was measured by the single-photon absorptiometry (SPA-4).</p><p><b>RESULTS</b>The BPb, UPb, HYP, ALP, BALP in the occupational lead exposure group were higher than those in the control group with significantly statistical difference in male (P < 0.01). The levels of BGP in the exposure group was higher than that in the control group without significantly statistical difference (P > 0.05). The BMD in the exposure group was lower than that in the control group without significantly statistical difference (P > 0.05). The BMD was significantly decreased in the groups of the UPb 10 approximately microg/g Cr level compared with the 0 approximately microg/g Cr group with the significant difference (P < 0.01). In males, the BMD was significantly decreased in the group of the BPb 300 approximately microg/L level compared with the 0 approximately microg/L group with the significant difference (P < 0.01). The levels of HYP, ALP, BALP, BGP in the UPb 20 approximately microg/g Cr group were significantly higher than those in the UPb 0 approximately microg/g Cr group (P < 0.05). The levels of HYP, ALP, BALP, BGP in the BPb 300 approximately microg/L group were significantly higher than those in the BPb 0 approximately microg/L group (P < 0.05). The prevalence of both osteoporosis and the abnormal bone metabolisms indexes would increase significantly with the increase of the lead exposure (P < 0.01) with the linear correlation (P < 0.01). But the prevalence of higher BGP had no significant correlation with UPb (P > 0.05). BMDs were calculated using BMDS Version 1.3.2 software and BMDLs were also determined. The BMDLs of BPb and UPb for lead-induced osteoporosis were higher than those representing the change of bone metabolism induced by lead.</p><p><b>CONCLUSIONS</b>The occupational exposure to lead could cause the decrease of the bone mineral density, lead to the osteoporosis, and may affect the bone metabolism.</p>

The effects of cadmium on the levels of insulin in smelters / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of cadmium on the levels of insulin and blood glucose in exposed workers.</p><p><b>METHODS</b>Ninety-eight cadmium-exposed workers in a smeltery in the mid-south district of our country were selected as the exposed subjects while the healthy doctors in the workers hospital who were not exposed to the cadmium were treated as the control. The subjects were grouped according to the exposure time, the blood cadmium and the urine cadmium. The variety of the level of serum insulin was investigated for the workers in different groups of the exposure time, the blood cadmium and the urine cadmium. The variety of the levels of the blood zinc and urine zinc were also determined. The relationships among the blood cadmium, the blood zinc and the serum insulin were analyzed.</p><p><b>RESULTS</b>The level of blood glucose in the group of the exposure time of more than 20 years [(4.9 +/- 0.6) mmol/L] was significantly higher than that in the control group [(4.6 +/- 0.60) mmol/L] with significantly statistical difference (P < 0.01). The level of serum insulin in the group of the exposure time of more than 10 years [(8.58 +/- 4.91) microIU/ml] was significantly lower than that in the control group [(11.57 +/- 5.42) microIU] with the significantly statistical difference (P < 0.05) and the level of serum insulin would be decreased significantly with the increase of the blood cadmium and urinary cadmium. The level of the urine zinc was increased significantly in the workers of the exposure time of more than 20 years. The correlation analysis indicated that the negative correlation was found between the level of serum insulin and the level of blood cadmium, as well as between the level of the serum insulin and the level of the urinary cadmium; the positive correlation was found between the level of blood glucose and the level of insulin, as well as between the level of blood glucose and the level of C peptide in serum.</p><p><b>CONCLUSION</b>The exposure to cadmium can cause the decrease of serum insulin and may affect the level of blood glucose.</p>

Relationship between plasma anti-metallothionein antibody and renal dysfunction in cadmium exposed workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate whether renal dysfunction induced by cadmium is related to plasma anti-metallothionein antibody (anti-MT Ab) in workers occupationally exposed to cadmium.</p><p><b>METHODS</b>The male workers in a smeltery were selected as the subjects for the exposure and effect assessment. The urine cadmium (UCd), the blood cadmium (BCd) and the occupational cadmium intake (TTCd) served as the exposure indexes while the urine beta(2) microglobulin (Ubeta(2)-MG), the N-acetyl-beta-D-glucosaminidase (UNAG) and the urine albumin concentration (UALB) served as the effect markers for the renal dysfunction caused by the cadmium. The titer of the plasma anti-metallothionein antibody was determined with the enzyme linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The UCd (3.16 microg/g Cr), BCd (9.28 microg/L), Ubeta(2)-MG (81.17 microg/g Cr) and UALB (7.03 mg/g Cr) in the occupational cadmium exposure group were significantly higher than those in the control group and the Ubeta(2)-MG, UNAG and UALB as well as the occurrence rate of abnormality would be increased with the increase of the level of the occupational cadmium exposure. There was no significant difference in the titer of anti-MT Ab between the exposure group and the control group (P > 0.05). The titer of the anti-MT Ab would not be increased with the increase of the dosage of the exposure and had no significant correlation with BCd, UCd and TTCd (P > 0.05). The positive correlation were found between anti-MT Ab and UNAG as well as between anti-MT Ab and Ubeta(2)-MG in the exposure group with the correlation coefficient of 0.302 and 0.218 respectively. The workers with high level anti-MT Ab are more susceptible to cadmium nephrotoxicity than those with low anti-MT Ab with the odds ratio (OR) value of 4.200 and the 95% CI between 1.213 and 14.541 (P < 0.05).</p><p><b>CONCLUSION</b>There is a dose-effect relationship between cadmium exposure and renal dysfunction in workers occupationally exposed to cadmium, but no correlation is found between cadmium exposure and plasma anti-MT Ab. The workers occupationally exposed to the cadmium with higher level of anti-MT Ab are easier to suffer from renal dysfunction caused by cadmium. Plasma anti-MT Ab could be used as a biomarker of susceptibility in the workers exposed to cadmium.</p>

Application of metallothionein gene isoforms expression as biomarkers in cadmium exposure / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of metallothionein (MT) gene expression level in human peripheral blood lymphocytes (HPBLs) as a biomarker in cadmium exposure.</p><p><b>METHODS</b>The MT gene expression level in HPBLs of workers exposed to cadmium was examined using RT-PCR technique, and the exposure assessment and effect assessment were conducted in exposed workers.</p><p><b>RESULTS</b>The basal MT-1A, IE, IF, IX and MT-2A expression level in workers exposed to cadmium were significantly higher than those in the control group (P < 0.05). The basal MT-1A, IE, IF, IX and MT-2A expression level would be significantly increased with the increase of the blood cadmium (BCd) level (P < 0.05). There was a trend of increase for the mRNA expression of the basal MT-1A, 1E, IF, IX, MT-2A, especially for the mRNA expression of MT-1A and MT-2A (P < 0.05) with the increase of the level of the urine cadmium (UCd). There was a good dose-response relationship between basal MT-1A expression and UCd. The basal MT-1A, IE, IF, IX and MT-2A expression level were significantly correlated with BCd (P < 0.05) while the basal MT-1A, IF and MT-2A expression level were significantly correlated with UCd (P < 0.05). There were dose-effect relationships of BCd to the basal MT-1E, MT-1F, MT-1X and MT-2X expression level respectively and there were also dose-effect relationships of UCd, beta(2)-MG and the urine metallothionein to the basal MT-1A expression.</p><p><b>CONCLUSION</b>The expression of the MT gene isoforms in HPBLs can serve as the biomarker for the cadmium exposure and MT-1A can also serve as the effective biomarkers for the cadmium-induced renal toxicity.</p>

The toxic effects of cadmium on pancreas / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>In order to explore the toxic effects of cadmium on functions of endocrine and exocrine of pancreas.</p><p><b>METHODS</b>96 SD rats were administered with cadmium at different doses (0, 50, 100, 200 mg/L) by drinking water for 30 days, 60 days and 90 days. The contents of cadmium and zinc in the blood and pancreas, also the glucose level in blood and urine, the levels of insulin and the activity of amylase were determined. The gene expression of metallothionein (MT), insulin and pancreatic amylase were also measured.</p><p><b>RESULTS</b>The results showed that the contents of cadmium in the serum and pancreas were higher than that of the control groups (P < 0.05). The contents of zinc in serum were decreased in the groups of 100 and 200 mg/L cadmium at the 90-day. As well as increased zinc in pancreas. The gene expression of insulin was not different compared with those of the control group except the middle-dose group at the 60-day. And the expression of amylase were higher in the groups of 100 and 200 mg/L cadmium at the 60-day and the 90-day. The expression of MT-1 and -2 were higher in the pancreas after cadmium administration.</p><p><b>CONCLUSION</b>It is suggested that cadmium could be accumulated in the pancreas and caused the change of the zinc levels. Then it resulted in the change of the expression of gene and protein, and influence of the functions of both endocrine and exocrine in pancreas.</p>