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OBJECTIVE To investigate the effect and mechanism of acute exposure to sodium cyanide(NaCN)on brain nerve damage induced by closed hypoxia in mice.METHODS ① Mice were randomly divided into hypoxia+NaCN 0(hypoxia control group),2.56,3.8,and 5.1 mg·kg-1 groups.After ip adminis-tration of different concentrations of NaCN,the mice were immediately placed into a closed hypoxic tank and the hypoxia survival time was observed.②Mice were divided into normal control,NaCN 3.8 mg·kg-1,hypoxia(30 and 60 min)and NaCN 3.8 mg·kg-1+hypoxia(30 and 60 min)groups.After grouping,the pH,oxygen saturation(sO2),oxygen tension(pO2)and carbon dioxide partial pressure(pCO2)of arterial blood of mice were detected using an arterial blood gas analyzer.The cortical cerebral blood flow of mice was detected using a laser speckle imager.The dry and wet brain tissue were weighed separately,and the brain moisture content was calculated.The kit was used to detect the activity of total superoxide dismutase(T-SOD)and the content of malondialdehyde(MDA)in the hippocampus.TUNEL staining was used to detect the apoptosis rate of cells in the hippocampus.HE staining was used to detect path-ological changes in the hippocampus.RESULTS ①Compared with the hypoxic control group,the sur-vival time of mice in the hypoxic+NaCN groups was significantly prolonged(P<0.01).②Compared with the normal control group,the hypoxia 30 min group showed upregulation of arterial blood p CO2(P<0.05),downregulation of p O2(P<0.05).The hypoxia 60 min group showed upregulation of arterial blood p CO2(P<0.05)and downregulation of cortical cerebral blood flow(P<0.05).In the NaCN 3.8 mg·kg-1 group,arterial blood p O2 and s O2 were significantly downregulated(P<0.05),so was cortical cerebral blood flow(P<0.01),but MDA content and T-SOD activity were significantly upregulated(P<0.01),and the brain moisture content was increased(P<0.01).Compared with the hypoxia 30 min group,s O2 and p O2 of arterial blood in the NaCN+hypoxia 30 min group were significantly upregulated(P<0.05),while p CO2 was significantly downregulated(P<0.05).Compared with the hypoxia group at corresponding time points,the NaCN+hypoxia 30 or 60 min groups showed significant downregulation of cerebral blood flow(P<0.01),significant upregulation of MDA content and T-SOD activity(P<0.01),and signifi-cant upregulation of brain moisture content(P<0.01).HE staining results showed that the NaCN 3.8 mg·kg-1 group and the NaCN+hypoxia group(30 or 60 min)showed significant cell swelling and vacuolization in cells in the hippocampal tissue,a decrease in the number of neurons,nuclear pyknosis and deep staining.TUNEL fluorescence results showed that the NaCN 3.8 mg·kg-1 group significantly increased the apop-tosis rate of the mouse hippocampus compared with the normal control group(P<0.05).The NaCN+ hypoxia 30 and 60 min groups significantly increased the apoptosis rate of the mouse hippocampus compared with the hypoxia group at corresponding time points(P<0.05).CONCLUSION NaCN can exacerbate hypoxia induced decrease in cerebral blood flow,oxidative stress in brain tissue,and neuro-nal apoptosis in mice,thereby reducing oxygen consumption in closed hypoxic tanks and prolonging their survival time.The mechanism is related to reduced utility of cell oxygen,delaying CO2 accumulation and increasing free oxygen in vivo.
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Objective To establish simple screening models for nonalcoholic fatty liver disease (NAFLD) in the adult Blang population. Methods Based on the survey data of metabolic diseases in the Blang people aged 18 years or above in 2017, 2993 respondents were stratified by sex and age (at an interval of 5 years) and then randomly divided into modeling group with 1497 respondents and validation group with 1496 respondents. Related information was collected, including demographic data, smoking, drinking, family history of diseases and personal medical history, body height, body weight, waist circumference, and blood pressure, and related markers were measured, including fasting plasma glucose, 2-hour postprandial plasma glucose or blood glucose at 2 hours after glucose loading, triglyceride, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase. The chi-square test was used for comparison of categorical data between two groups. Logistic regression analysis was used to establish the screening model. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value were used to evaluate the screening performance of established models versus existing models in the study population, and the DeLong method was used for comparison of AUC. Results Three screening models for NAFLD were established based on physical and biochemical measurements, i.e., simple noninvasive model 1 (age, body mass index, and waist circumference), noninvasive model 2 with the addition of blood pressure, and model 3 with the combination of hematological parameters (diabetes and ALT/AST). In the modeling group, the three models had an AUC of 0.881 (95% confidence interval [ CI ]: 0.864-0.897), 0.892 (95% CI : 0.875-0.907), and 0.894 (95% CI : 0.877-0.909), respectively, and there was a significant difference between model 1 and models 2/3 ( P =0.004 0 and P 0.05). Based on the overall consideration of screening performance, invasiveness, and cost, the simple noninvasive model 1 was considered the optimal screening model for NAFLD in this population. Model 1 had the highest Youden index at the cut-off value of 5 points, and when the score of ≥5 points was selected as the criteria for NAFLD, the model had a sensitivity of 86.5%, a specificity of 79.7%, a positive predictive value of 50.3%, and a negative predictive value of 96.1% in the modeling group and a sensitivity of 85.6%, a specificity of 80.6%, a positive predictive value of 51.7%, and a negative predictive value of 95.8% in the validation group. Conclusion The NAFLD screening models established for the adult Blang population based on age and obesity indicators have relatively higher sensitivity, specificity, and negative predictive value, and this tool is of important practical significance for the intervention of NAFLD and its closely related metabolic diseases in this population.
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Objective To investigate the prevalence and associated risk factors of diabetes and prediabetes in Blang ethnic adults in Menghai county. Methods A cross-sectional survey including 3 365 Blang ethnic adults (aged 18 and above from 5 administrative villages) was conducted from February 2017 to March 2017 in Menghai county. A questionnaire, physical examination, and blood assays were included in the survey. Finally,a total of 3 237 adults with complete data were selected into this analysis. Results The standardized prevalence of diabetes and prediabetes in Blang ethnic adults were estimated based on the sixth national census in 2010. According to the 1999 WHO criteria, the overall standardized prevalence of diabetes and prediabetes were 8.5% (men: 10.2%, women: 6.8%) and 16.1% (men: 18.0%, women: 14.1%), in which the standardized prevalence of newly diagnosed diabetes among the total population was 7.3% (men: 8.7%, women: 5.8%). Multivariable multinominal logistic regression analyses showed that age, hypertension, hypertriglyceridemia, and central obesity were significantly positively associated with both diabetes and prediabetes, with the corresponding odds ratios of 1.74 and 1.37, 2.39 and 2.02, 2.30 and 1.34, 2.55 and 1.73, respectively. Conclusion The prevalence of diabetes is relatively high in Blang ethnic adults in Menghai county. Improving knowledge of diabetes among the local population is one of key steps in the prevention of diabetes.