Effects of heat exposure and vitamin C intervention on oxidative stress and blood pressure changes in treadmill rats / 中华劳动卫生职业病杂志

Objective: To investigate the effect of oxidative stress caused by heat exposure on the blood pressure increase of treadmill rats and the intervention of antioxidants. Methods: In June 2021, Twenty-four healthy SD male rats were randomly divided into four groups: normal temperature feeding, normal temperature treadmill, high temperature treadmill and high temperature treadmill supplementation with vitamin C groups, 6 rats in each group. The rats run on the platform in normal temperature or heat exposure environment for 30 min in the morning and in the afternoon daily, 6 days per week. The daily vitamin C supplement dose of high temperature treadmill supplementation with vitamin C group was 10 mg/kg. BP recordings were done at the end of the week. The rat vascular lipofuscin (LF) was detected by ELISA, the rat serum nitric oxide (NO) was detected by nitrate reductase method, the serum malondialdehyde (MDA) was detected by thibabituric acid method, the serum glutathione peroxidase (GPx) and superoxide dismutase (SOD) were detected by chemiluminescence method, and the serum catalase (CAT) was detected by ammonium molybdate method. The total antioxidant capacity (T-AOC) of serum was measured by iron reduction/antioxidant capacity method, and the content of nuclear erythroid 2-related factor 2 (Nrf2) in vascular tissue was measured by Western blot. The intra-group mean was compared by repeated measurement analysis of variance, and the inter-group mean was compared by single-factor analysis of variance and post-event LSD-t test. Results: Compared with the previous time point, the systolic BP and diastolic BP of the high temperature treadmill group were significantly increased at 7, 14 and 21 d, and decreased at 28 d which were higher than the initial level (P<0.05), and the systolic BP and diastolic BP values at each experimental time point were significantly higher than those of normal temperature treadmill group (P<0.001). The changes of thickening of the artery wall, no smoothing of the endodermis and irregular arrangement of muscle cells in high temperature treadmill group were observed. Compared with the normal temperature treadmill group, the content of MDA in serum, and LF in vascular tissue were significantly increased, the activities of SOD, CAT, T-AOC, the content of NO in serum, and the expression of Nrf2 in vascular tissue were significantly decreased in high temperature treadmill group (P<0.05). Compared with the high temperature treadmill group, the systolic BP and diastolic BP values at 7, 14, 21 and 28 d, the content of serum MDA and LF in vascular tissue were significantly decreased, the activities of CAT and T-AOC, and the expression of Nrf2 in vascular tissue significantly increased (P<0.05), the histopathological changes of the artery wall improved in high temperature treadmill supplementation with vitamin C group. Conclusion: Heat exposure has effect on oxidative stress, which may be related to the increase of BP. Vitamin C as an anti-oxidative enhancer can prevent those negative effects, which could alleviate the pathological changes of vessel intima in heat-exposed rats. And the Nrf2 may be a regulated factor to vascular protection.

A prevalence study on occupational stress and hypertension among steel production workers / 中国职业医学

OBJECTIVE: To analyze the correlation between occupational stress and hypertension in steel production workers.METHODS: By the stratified cluster sampling method,1 580 steel production workers from an iron and steel group company were selected as study subjects. Occupational stress was measured by the Chinese version of Job Content Questionnaire.The identification of having occupational stress was the ratio of job requirement dimension score over job self-decision dimension score turned to be ≥1. 00. The steel production workers' blood pressure was measured by the updated mercury sphygmomanometer. The effect of occupational stress on blood pressure in steel production workers was analyzed. RESULTS: The dimension score of job self-decision in hypertension group was lower than that in non-hypertension group [20( 16,23) vs 20( 17,24) scores,P < 0. 05]. There was no statistical significant difference in occupational stress ratio,job requirement and social support dimension scores between two groups( P > 0. 05). The multiple logistic regression analysis showed that job self-decision and social support scores were negatively correlated with the incidence of hypertension [odds ratios( 95% confidence intervals) were 0. 68( 0. 51,0. 90) and 0. 54( 0. 45,0. 76),P < 0. 01]. CONCLUSION: Job selfdecision and social support are the influencing factors of the incidence of hypertension in steel production workers. The correlation among occupational stress,job requirement and hypertension are not found in steel production workers.

High Physical Activity is Associated with an Improved Lipid Profile and Resting Heart Rate among Healthy Middle-aged Chinese People / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the effects of physical activity (PA) on dyslipidemia and elevated resting heart rate (RHR) in a large-scale cross-sectional study in China.</p><p><b>METHODS</b>We recruited community-based individuals who were 40-60 years old using a cluster sampling method. The PA levels of the participants were classified as low, moderate, or high, using the International Physical Activity Questionnaire. Dyslipidemia was defined as the detection of abnormalities in lipid indicators, and 4 lipid parameters were evaluated using fasting blood samples. Multivariate logistic regression analyses were used to evaluate the associations of PA with dyslipidemia and RHR.</p><p><b>RESULTS</b>A total of 10,321 participants (38.88% men) were included in this study. The percentages of individuals with high, moderate, and low PA levels were 46.5%, 43.9%, and 9.6%, respectively. In both men and women, high PA provided odds ratios of 0.88 [95% confidence interval (CI): 0.83, 0.94] for dyslipidemia and 0.82 (95% CI: 0.73, 0.92) for elevated RHR, compared to participants with low PA.</p><p><b>CONCLUSION</b>Our data suggested that substantial health benefits (related to dyslipidemia and elevated RHR) occurred at higher intensity PA, with greater energy consumption, in middle-aged Chinese people, and particularly in men.</p>

Association of TNF-alpha-238G/A and 308 G/A gene polymorphisms with pulmonary tuberculosis among patients with coal worker's pneumoconiosis / 生物医学与环境科学（英文）

<p><b>OBJECTIVES</b>Tumor necrosis factor-alpha (TNF-alpha) may play an important role in host's immune response to mycobacterium tuberculosis (M. tuberculosis) infection. This study was to investigate the association of TNF-alpha gene polymorphism with pulmonary tuberculosis (TB) among patients with coal worker's pneumoconiosis (CWP).</p><p><b>METHODS</b>A case-control study was conducted in 113 patients with confirmed CWP complicated with pulmonary TB and 113 non-TB controls with CWP. They were matched in gender, age, job, and stage of pneumoconiosis. All participants were interviewed with questionnaires and their blood specimens were collected for genetic determination with informed consent. The TNF-alpha gene polymorphism was determined with polymerase chain reaction of restriction fragment length polymorphism (PCR-RFLP). Frequency of genotypes was assessed for Hardy-Weinberg equilibrium by chi-square test or Fisher's exact probability. Factors influencing the association of individual susceptibility with pulmonary TB were evaluated with logistic regression analysis. Gene-environment interaction was evaluated by a multiplicative model with combined OR. All data were analyzed using SAS version 8.2 software.</p><p><b>RESULTS</b>No significant difference in frequency of the TNF-alpha-308 genotype was found between CWP complicated with pulmonary TB and non-TB controls (chi2 = 5.44, P = 0.07). But difference in frequency of the TNF-alpha-308 A allele was identified between them (chi2 = 5.14, P = 0.02). No significant difference in frequencies of the TNF-alpha-238 genotype and allele (P = 0.23 and P = 0.09, respectively) was found between cases and controls either, with combined (GG and AA) OR of 3.96 (95% confidence interval of 1.30-12.09) at the -308 locus of the TNF-alpha gene, as compared to combination of the TNF-alpha-238 GG and TNF-alpha-308 GG genotypes. Multivariate-adjusted odds ratio of the TNF-alpha-238 GG and TNF-alpha-308 GA genotypes was 1.98 (95% CI of 1.06-3.71) for risk for pulmonary TB in patients with CWP. There was a synergic interaction between the TNF-alpha-308 GG genotype and body mass index (OR = 4.92), as well as an interaction between the TNF-alpha-308 GG genotype and history of BCG immunization or history of TB exposure. And, the interaction of the TNF-alpha-238 GG genotype and history of BCG immunization or TB exposure with risk for pulmonary TB in them was also indicated.</p><p><b>CONCLUSIONS</b>TNF-alpha-308 A allele is associated with an elevated risk for pulmonary TB, whereas TNF-alpha-238 A allele was otherwise.</p>

Study on the determinants of Helicobacter pylori infection among coal miners / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the prevalence and determinants of Helicobacter pylori (H. pylori) infection among coal miners and to seek for competent preventive measures.</p><p><b>METHODS</b>425 coal miners from three coal mines, Tangshan, Daxing, and baodian were chosen under stratified random cluster sampling. Face to face interview was conducted to fill the unified questionnaires by trained interviewers. 306 subjects underwent gastroenduoscopy to detect the situation of the gastroenduodenal diseases, according to the Sydney System of diagnosis. Mucosa biopsies were also undertaken according to the regulated location for culture of H. pylori and for pathological examination. Blood samples were obtained to detect the anti-HpU-IgG by enzyme-linked immunosorbent assay (ELISA). H. pylori infection was determined through culture and ELISA but confirmed under the standards set at the National Congress on Gastroduodenal Diseases in 1999.</p><p><b>RESULTS</b>Among 425 eligible coal miners being tested, 297 (69.9%) were H. pylori positive and the rate for those working underground (74.0%) was higher than that of those working on ground (P=0.004). No difference was found among coal miners between the three mines (P >0.05). Age, living conditions in childhood, number of current family members, the amount of alcohol intake and ways of eating at home were strongly associated with the status of H. pylori infection.</p><p><b>CONCLUSIONS</b>Difference of H. pylori infection prevalences between the underground and the aboveground coal miners was noticed. Determinants that influencing the H. pylori infection would include socioeconomic factors, individual habits and ways of eating at home.</p>