Association between temperature and mortality: a multi-city time series study in Sichuan Basin, southwest China.

BACKGROUND: There are few multi-city studies on the association between temperature and mortality in basin climates. This study was based on the Sichuan Basin in southwest China to assess the association of basin temperature with non-accidental mortality in the population and with the temperature-related mortality burden. METHODS: Daily mortality data, meteorological and air pollution data were collected for four cities in the Sichuan Basin of southwest China. We used a two-stage time-series analysis to quantify the association between temperature and non-accidental mortality in each city, and a multivariate meta-analysis was performed to obtain the overall cumulative risk. The attributable fractions (AFs) were calculated to access the mortality burden attributable to non-optimal temperature. Additionally, we performed a stratified analyses by gender, age group, education level, and marital status. RESULTS: A total of 751,930 non-accidental deaths were collected in our study. Overall, 10.16% of non-accidental deaths could be attributed to non-optimal temperatures. A majority of temperature-related non-accidental deaths were caused by low temperature, accounting for 9.10% (95% eCI: 5.50%, 12.19%), and heat effects accounted for only 1.06% (95% eCI: 0.76%, 1.33%). The mortality burden attributable to non-optimal temperatures was higher among those under 65 years old, females, those with a low education level, and those with an alternative marriage status. CONCLUSIONS: Our study suggested that a significant association between non-optimal temperature and non-accidental mortality. Those under 65 years old, females, and those with a low educational level or alternative marriage status had the highest attributable burden.

Associations between major dietary patterns and blood pressure among Southwest Chinese: A cross-sectional analysis based on the China Multi-Ethnic Cohort (CMEC) study.

BACKGROUND AND AIMS: In the less developed multi-ethnic regions (LEMRs) of Southwest China, the associations between dietary patterns and blood pressure (BP) values remain unclear. We aimed to investigate such associations and related effect modifiers. METHODS AND RESULTS: This study included 81,433 participants from the China Multi-Ethnic Cohort Study. Dietary intakes during the year before the interview were measured with the Quantitative Food Frequency Questionnaire. Three major dietary patterns that were highly in line with geographical and ethnic distributions of the study population, i.e., "Sichuan Basin," "Yunnan-Guizhou Plateau," and "Qinghai-Tibet Plateau," were derived using principal component factor analysis. The multilinear regression model combined with inverse probability of exposure weighting was used to estimate the associations between dietary patterns and BP values. Comparing the highest with the lowest quintiles, the Sichuan Basin dietary pattern (characterized by urban lifestyles) was associated with 2.67 mmHg lower systolic blood pressure (SBP) (95% CI: -3.07 to -2.27) and 0.89 mmHg lower diastolic blood pressure (95% CI: -1.12 to -0.65). In contrast, both the Yunnan-Guizhou Plateau (characterized by agricultural lifestyles) and the Qinghai-Tibet Plateau dietary patterns (characterized by nomadic lifestyles) showed positive associations with BP. In the stratified analysis, the associations between dietary patterns and SBP were significantly stronger in women than in men for all three kinds of dietary patterns. CONCLUSION: Both major dietary patterns and their associations with BP showed a substantial disparity in LEMRs of Southwest China. Dietary patterns in regions of higher socioeconomic status are more conducive to reducing the rising of BP, especially for women and urban residents, which might provide insights into the BP control in LEMRs of Southwest China.

Association between spicy food and hypertension among Han Chinese aged 30-79 years in Sichuan Basin: a population-based cross-sectional study.

BACKGROUND: While spicy food is believed to have cardiovascular-protective effects, its impact on hypertension remains uncertain due to conflicting findings from previous studies. This study aimed to explore the association between spicy food and hypertension in Sichuan Basin, China. METHODS: The baseline data of 43,657 residents aged 30-79 in the Sichuan Basin were analyzed including a questionnaire survey (e.g., sociodemographics, diet and lifestyle, medical history), medical examinations (e.g., height, body weight, and blood pressure), and clinical laboratory tests (e.g., blood and urine specimens). Participants were recruited by multi-stage, stratified cluster sampling in consideration of both sex ratio and age ratio between June 2018 and February 2019. Multivariable logistic regression was performed to explore the effect of spicy food on hypertension and multivariable linear regression was applied to estimate the effect of spicy food on systolic and diastolic blood pressure (SBP/DBP). RESULTS: Concerning hypertension, negative associations with spicy food consumption were observed only in females: compared to those who do not eat spicy food, the odds ratios of consuming spicy food 6-7 days/week, consuming spicy food with strong strength, and years of eating spicy food-to-age ratio were 0.886 (0.799, 0.982), 0.757 (0.587, 0.977), 0.632 (0.505, 0.792), respectively. No significant association was found in males (All P trends > 0.05). In the stratified analyses, participants in the subgroup who were 50 to 79 years old (OR, 95%CI: 0.814, 0.763, 0.869), habitually snored (OR, 95%CI: 0.899, 0.829, 0.976), had a BMI < 24 kg/m2 (OR, 95%CI: 0.886, 0.810, 0.969), had a normal waist circumference (OR, 95%CI: 0.898, 0.810, 0.997), and had no dyslipidemia (OR, 95%CI: 0.897, 0.835, 0.964) showed a significantly stronger association. For SBP, consuming spicy food had negative effects in both genders, but the effect was smaller in males compared to females: among males, the ß coefficients for consuming spicy food 1-2 days/week, weak strength, and years of eating spicy food-to-age ratio were 0.931 (-1.832, -0.030), -0.639 (-1.247, -0.032), and - 2.952 (-4.413, -1.492), respectively; among females, the ß coefficients for consuming spicy food 3-5 days/week, 6-7 days/week, weak strength, moderate strength, and years of eating spicy food-to-age ratio were - 1.251 (-2.115, -0.388), -1.215 (-1.897, -0.534), -0.788 (-1.313, -0.263), -1.807 (-2.542, -1.072), and - 5.853 (-7.195, -4.512), respectively. For DBP, only a positive association between the years of eating spicy food-to-age ratio and DBP was found in males with ß coefficient (95%CI ) of 1.300 (0.338, 2.263); Little association was found in females (all P trends > 0.05), except for a decrease of 0.591 mmHg ( 95%CI: -1.078, -0.105) in DBP among participants who consumed spicy food 1-2 days/week, compared to those who did not consume spicy food. CONCLUSION: Spicy food may lower SBP and has an antihypertensive effect, particularly beneficial for women and individuals with fewer risk factors in the Sichuan Basin. Spicy food consumption may decrease DBP in women but increase it in men. Further multicenter prospective cohort studies are needed to confirm these findings.

Effects of ambient temperature on mortality among elderly residents of Chengdu city in Southwest China, 2016-2020: a distributed-lag non-linear time series analysis.

BACKGROUND: With complex changes in the global climate, it is critical to understand how ambient temperature affects health, especially in China. We aimed to assess the effects of temperature on daily mortality, including total non-accidental, cardiovascular disease (CVD), respiratory disease, cerebrovascular disease, and ischemic heart disease (IHD) mortality between 2016 and 2020 in Chengdu, China. METHODS: We obtained daily temperature and mortality data for the period 2016-2020. A Poisson regression model combined with a distributed-lag nonlinear model was used to examine the association between temperature and daily mortality. We investigated the effects of individual characteristics by sex, age, education level, and marital status. RESULTS: We found significant non-linear effects of temperature on total non-accidental, CVD, respiratory, cerebrovascular, and IHD mortality. Heat effects were immediate and lasted for 0-3 days, whereas cold effects persisted for 7-10 days. The relative risks associated with extreme high temperatures (99th percentile of temperature, 28 °C) over lags of 0-3 days were 1.22 (95% confidence interval [CI]: 1.17, 1.28) for total non-accidental mortality, 1.40 (95% CI: 1.30, 1.50) for CVD morality, 1.34 (95% CI: 1.24, 1.46) for respiratory morality, 1.33 (95% CI: 1.20, 1.47) for cerebrovascular mortality, and 1.38 (95% CI: 1.20, 1.58) for IHD mortality. The relative risks associated with extreme cold temperature (1st percentile of temperature, 3.0 °C) over lags of 0-14 days were 1.32 (95% CI: 1.19, 1.46) for total mortality, 1.45 (95% CI: 1.24, 1.68) for CVD morality, 1.28 (95% CI: 1.09, 1.50) for respiratory morality, 1.36 (95% CI: 1.09, 1.70) for cerebrovascular mortality, and 1.26 (95% CI: 0.95, 1.68) for IHD morality. We found that hot and cold affects were greater in those over 85 years of age, and that women, individuals with low education levels, and those who were widowed, divorced, or never married, were more vulnerable. CONCLUSIONS: This study showed that exposure to hot and cold temperatures in Chengdu was associated with increased mortality, with people over 85 years old, women, those with low education levels, and unmarried individuals being more affected by hot and cold temperatures.

Impacts of exposure to humidex on cardiovascular mortality: a multi-city study in Southwest China.

BACKGROUND: Many studies have reported the association between ambient temperature and mortality from cardiovascular disease (CVD). However, the health effects of humidity are still unclear, much less the combined effects of temperature and humidity. In this study, we used humidex to quantify the effect of temperature and humidity combined on CVD mortality. METHODS: Daily meteorological, air pollution, and CVD mortality data were collected in four cities in southwest China. We used a distributed lag non-linear model (DLNM) in the first stage to assess the exposure-response association between humidex and city-specific CVD mortality. A multivariate meta-analysis was conducted in the second stage to pool these effects at the overall level. To evaluate the mortality burden of high and low humidex, we determined the attributable fraction (AF). According to the abovementioned processes, stratified analyses were conducted based on various demographic factors. RESULTS: Humidex and the CVD exposure-response curve showed an inverted "J" shape, the minimum mortality humidex (MMH) was 31.7 (77th percentile), and the cumulative relative risk (CRR) was 2.27 (95% confidence interval [CI], 1.76-2.91). At extremely high and low humidex, CRRs were 1.19 (95% CI, 0.98-1.44) and 2.52 (95% CI, 1.88-3.38), respectively. The burden of CVD mortality attributed to non-optimal humidex was 21.59% (95% empirical CI [eCI], 18.12-24.59%), most of which was due to low humidex, with an AF of 20.16% (95% eCI, 16.72-23.23%). CONCLUSIONS: Low humidex could significantly increase the risk of CVD mortality, and vulnerability to humidex differed across populations with different demographic characteristics. The elderly (> 64 years old), unmarried people, and those with a limited level of education (1-9 years) were especially susceptible to low humidex. Therefore, humidex is appropriate as a predictor in a CVD early-warning system.

[PM 2.5 and Emergency Calls for Health with Respiratory Diseases in Chengdu in 2017].

OBJECTIVE: To determine the association between daily particulate matter 2.5 (PM 2.5) mass and emergency calls for help with respiratory diseases. METHODS: Semi-parametric generalized additive model was established to determine the association between daily PM 2.5 and emergency calls for help with respiratory diseases in 2017 in Chengdu, after adjustments for time trend and variations in the days of the week and weather conditions. RESULTS: In 2017, a total of 9 309 emergency calls for help with respiratory diseases were recorded in Chengdu: on average 26 calls a day. Over the year, Chengdu reported a mean PM 2.5 mass concentration of 53.6 µg/m 3, an average temperature of 16.6 ℃, and an average relative humidity of 81.2%. The single pollutant model with lag time effect showed that a 10 µg/m 3 increase in PM 2.5 was associated with an increase of 1.26% (95% confidence interval ( CI) 0.56%-1.97%) emergency calls for help with respiratory diseases. The exposure-response was almost in a direct line. The dual pollutant model found that O 3 8-hour sliding average (O 3-8 h) enhanced the effect of PM 2.5 on emergency calls for help with respiratory diseases. CONCLUSION: Outdoor PM 2.5 is a significant predictor of emergency calls for help with respiratory diseases in Chengdu.

Probable Evidence of Aerosol Transmission of SARS-COV-2 in a COVID-19 Outbreak of a High-Rise Building.

Although it is well established that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be transmitted through aerosols, the mode of long-range aerosol transmission in high-rise buildings remains unclear. In this study, we analyzed an outbreak of coronavirus disease 2019 (COVID-19) that occurred in a high-rise building in China. Our objective was to investigate the plausibility of aerosol transmission of SARS-CoV-2 by testing relevant environmental variables and measuring the dispersion of a tracer gas in the drainage system of the building. The outbreak involved 7 infected families, of which 6 were from vertically aligned flats on different floors. Environmenìtal data revealed that 3 families' bathrooms were contaminated by SARS-CoV-2. In our tracer experiment, we injected tracer gas (CO2) into the dry floor drains and into water-filled toilets in the index case' s bathroom. Our findings showed that the gas could travel through vertical pipes by the dry floor drains, but not through the water of the toilets. This indicates that dry floor drains might facilitate the transmission of viral aerosols through the sewage system. On the basis of circumstantial evidence, long-range aerosol transmission may have contributed to the community outbreak of COVID-19 in this high-rise building. The vertical transmission of diseases through aerosols in high-rise buildings demands urgent attention.

Low-dose Cu exposure enhanced α-synuclein accumulation associates with mitochondrial impairments in mice model of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder that mainly affects the elder population, and its etiology is enigmatic. Both environmental risks and genetics may influence the development of PD. Excess copper causes neurotoxicity and accelerates the progression of neurodegenerative diseases. However, the underlying mechanisms of copper-induced neurotoxicity remain controversial. In this study, A53T transgenic α-synuclein (A53T) mice and their matching wild-type (WT) mice were treated with a low dose of copper (0.13 ppm copper chlorinated drinking water, equivalent to the copper exposure of human daily copper intake dose) for 4 months, and copper poisoning was performed on human A53T mutant SHSY5Y cells overexpressed with α-synuclein (dose of 1/4 IC50), to test the effects of copper exposure on the body. The results of the open field test showed that the moto function of Cu-treated mice was impaired. Proteomics revealed changes in neurodevelopment, transport function, and mitochondrial membrane-related function in Cu-treated WT mice, which were associated with reduced expression of mitochondrial complex (NDUFA10, ATP5A), dopamine neurons (TH), and dopamine transporter (DAT). Mitochondrial function, nervous system development, synaptic function, and immune response were altered in Cu-treated A53T mice. These changes were associated with increased mitochondrial splitting protein (Drp1), decreased mitochondrial fusion protein (OPA1, Mfn1), abnormalities in mitochondrial autophagy protein (LC3BII/I, P62), decreased dopamine neuron (TH) expression, increased α-synuclein expression, inflammatory factors (IL-6, IL-1ß, and TNF-α) release and microglia (Iba1) activation. In addition, we found that Cu2+ (30 µM) induced excessive ROS production and reduced mitochondrial ATP production in human A53T mutant α-synuclein overexpressing SHSY5Y cells by in vitro experiments. In conclusion, low-dose copper treatment altered critical proteins involved in mitochondrial, neurodevelopmental, and inflammatory responses and affected mitochondria's ROS and ATP production levels.

The association between perchlorate in drinking water and height and weight of children and adolescents in Southwest China: a retrospective cross-sectional study.

Objective: To investigate the association between the concentration of perchlorate in drinking water and the height and weight of children and adolescents in Sichuan Province. Methods: Perchlorate in the drinking water of 24 counties in Sichuan Province from 2021 to 2022 was detected and analyzed, 66 drinking water samples were collected, and the content of perchlorate in drinking water during the wet season and dry season was detected by ultra-high performance liquid chromatography in series. The linear mixed effect model was used to estimate the relationship between perchlorate in drinking water and the height and weight of 144,644 children and adolescents, and 33 pieces of local average wage data were used as confounding factors for quality control. Results: After controlling the age, gender, and local economic situation, we found that the concentration of perchlorate in drinking water increased by 10 µg/L is associated with a 1.0 cm decrease in height and a 1.6 kg decrease in weight in children and adolescents (p < 0.05). Conclusion: The concentration of perchlorate in drinking water may be negatively correlated with the height and weight of children.

The mediation role of blood lipids on the path from air pollution exposure to MAFLD: A longitudinal cohort study.

BACKGROUND & AIMS: Recent cross-sectional studies found that exposure to ambient air pollution (AP) was associated with an increased risk of metabolic dysfunction-associated fatty liver disease (MAFLD). The alternation of blood lipids may explain the association, but epidemiological evidence is lacking. We aimed to examine whether and to what extent the association between long-term exposure to AP and incident MAFLD is mediated by blood lipids and dyslipidemia in a prospective cohort. METHODS: We included 6350 participants from the China Multi-Ethnic Cohort (CMEC, baseline 2018-2019, follow-up 2020-2021). Three-year average (2016-2018) of AP (PM1, PM2.5, PM10, NO2), blood lipids (TC, LDL-C, HDL-C, TG with their combinations) and incident MAFLD for each individual were assessed chronologically. Linear and logistic regression was used to assess the associations among AP, blood lipids, and MAFLD, and the potential mediation effects of blood lipids were evaluated using causal mediation analysis. RESULTS: A total of 744 participants were newly diagnosed with MAFLD at follow-up. The odds ratios of MAFLD associated with a 10 µm increase in PM1, PM2.5, and NO2 were 1.35 (95 % CI: 1.14, 1.58), 1.34 (1.10, 1.65) and 1.28 (1.14, 1.44), respectively. Blood lipids are important mediators between AP and incident MAFLD. LDL-C (Proportion Mediated: 6.9 %), non-HDL (13.4 %), HDL-C (20.7 %), LDL/HDL (30.1 %), and dyslipidemia (6.5 %) significantly mediated the association between PM2.5 and MAFLD. For PM1, the indirect effects were similar to those for PM2.5, with a larger value for the direct effect, and the mediation proportion by blood lipids was less for NO2. CONCLUSION: Blood lipids are important mediators between AP and MAFLD, and can explain 5 %-30 % of the association between AP and incident MAFLD, particularly cholesterol-related variables, indicating that AP could lead to MAFLD through the alternation of blood lipids. These findings provided mechanical evidence of AP leading to MAFLD in epidemiological studies.

Altitude and metabolic syndrome in China: Beneficial effects of healthy diet and physical activity.

Background: The correlation between altitude and metabolic syndrome has not been extensively studied, and the mediation effects of diet and physical activity remain unclear. We evaluated the cross-sectional correlations between altitude and metabolic syndrome and the possible mediation effects of diet and physical activity in China. Methods: We included 89 485 participants from the China Multi-Ethnic Cohort. We extracted their altitude information from their residential addresses and determined if they had metabolic syndrome by the presence of three or more of the following components: abdominal obesity, reduced high-density lipoprotein cholesterol (HDL-C), elevated triglycerides, elevated glucose, and high blood pressure at recruitment. We conducted multivariable logistic regression and mediation analyses for all and separately for Han ethnic participants. Results: The participants had a mean age of 51.67 years and 60.56% were female. The risk difference of metabolic syndrome was -3.54% (95% confidence interval (CI) = -4.24, -2.86) between middle and low altitudes, -1.53% (95%CI = -2.53, -0.46) between high and low altitudes, and 2.01% (95% CI = 0.92, 3.09) between high and middle altitudes. Of the total estimated effect between middle and low altitude, the effect mediated by increased physical activity was -0.94% (95% CI = -1.04, -0.86). Compared to low altitude, the effects mediated by a healthier diet were -0.40% (95% CI = -0.47, -0.32) for middle altitude and -0.72% (95% CI = -0.87, -0.58) for high altitude. Estimates were similar in the Han ethnic group. Conclusions: Living at middle and high altitudes was significantly associated with lower risk of metabolic syndrome compared to low altitude, with middle altitude having the lowest risk. We found mediation effects of diet and physical activity.

Protective effect of CTRP6 on cerebral ischemia/reperfusion injury by attenuating inflammation, oxidative stress and apoptosis in PC12 cells.

The newly identified C1q/tumor necrosis factor (TNF)-related protein-6 (CTRP6) is a highly conserved paralog of adiponectin with modulatory effects on metabolism and inflammation. However, the role of CTRP6 in cerebral ischemia/reperfusion (I/R) injury remains unknown. The aim of the present study was to explore the protective effects of CTRP6 against cerebral I/R injury and elucidate the possible underlying mechanisms. Oxygen­glucose deprivation and reperfusion (OGD/R) was used to induce an I/R injury model in vitro. Western blotting, reverse transcription­quantitative PCR, ELISA and flow cytometry analysis were used to measure the levels of CTRP6 along with those of inflammation­, oxidative stress­ and apoptosis­related cytokines. The results indicated that CTRP6 expression was markedly downregulated following OGD/R. OGD/R also increased i) the activities of pro­inflammatory factors TNF­α, interleukin (IL)­1ß, IL­6 and the levels of the oxidative products reactive oxygen species and malondialdehyde; ii) the ratio of apoptotic PC12 cells and iii) the expression of the pro­apoptotic proteins Bax, cleaved caspase­3 and cleaved caspase­9. In addition, the activities of the anti­inflammatory factors IL­10 and superoxide dismutase and the expression of the anti­apoptotic protein Bcl­2 were decreased. However, overexpression of CTRP6 rescued OGD/R­stimulated exacerbation of inflammation, oxidative stress and apoptosis. Mechanistically, OGD/R activated Ras homolog family member A (RhoA)/Rho­associated coiled­coil­containing protein kinase (Rock)/phosphatase and tensin homologue deleted on chromosome 10 (PTEN) signaling, whereas CTRP6 overexpression restored the expression of RhoA, Rock, PTEN, phosphoinositide 3­kinase (PI3K) and protein kinase B (Akt). Furthermore, when CTRP6 and RhoA were overexpressed at the same time, RhoA abolished the protective effects of CTRP6 overexpression on OGD/R­induced inflammation, oxidative stress and apoptosis, while the presence of a PTEN inhibitor recovered the protective effects of CTRP6. Taken together, the findings of the present study indicate that CTRP6 attenuates cerebral ischemia/reperfusion­induced inflammation, oxidative stress and apoptosis via inhibiting the RhoA/Rock/PTEN pathway, thereby activating PI3K/Akt signaling.

Increased damage of exon 5 of p53 gene in workers from an arsenic plant.

Mutagenesis is a multistage process. Substitution mutations can be induced by base modified through alteration of pairing property. Mutations of exon 5 and 8 of p53 gene have been found in most arsenicosis patients with precarcinomas and carcinomas, but never in arsenicosis individuals without precarcinomas and carcinomas. This study investigates whether base modification exists in exon 5 and 8 of p53 gene, and explores the dose-effect relationship between damage of exon 5 of p53 gene and urinary arsenic. Concentrations of urinary 8-hydroxydeoxyguanine (8-OHdG) are analyzed to identify the occurrence of DNA damage. The real-time PCR developed by Sikorsky et al. is applied to detect base modification in exon 5 and 8 of p53 gene for apparently healthy participants. Our results show that the mean total arsenic concentrations of two exposed groups from an arsenic plant are significantly elevated compared with the control group, and the damage level of exon 5 of the high-exposed group is significantly higher than that of the control group, but which does not happen in exon 8. The closely correlation between the damage index of exon 5 and urinary organic arsenic concentration are found. Concentration of 8-OHdG of the high-exposed group is significantly higher than that of the control group. These results imply that base modification in exon 5 of p53 gene can be induced by arsenic. In addition, our study suggests that the damage level of exon 5 is a useful biomarker to assess adverse health effect levels caused by chronic exposure to arsenic.

[Study on the association between urinary organic arsenic and 8-hydroxydeoxyguanine in workers exposed to arsenic].

OBJECTIVE: To evaluate the association between metabolism of arsenic and DNA oxidative damage in workers in a arsenic mill. METHODS: Urinary organic arsenic and 8-hydroxydeoxyguanine were detected in 37 workers highly exposed to arsenic and 16 administrative and logistic staff with mild exposure in a arsenic mill in Yunnan province, and also 28 local people who did not have the exposure in the near past time. The correlation between metabolism of arsenic and DNA oxidative damage was evaluated. RESULTS: The urinary organic arsenic concentration was respectively (0.48 +/- 0.37) mg/L and (0.08 +/- 0.05) mg/L for men with high and low exposure, and was respectively 0.11 mg/L and (0.30 +/- 0.24) mg/ L for women with high and low exposure, while it was lower than 0.02 mg/L in the controls. Urinary 8-hydroxydeoxyguanine concentration was (18.07 +/- 11.68) micromol/mol creatinine, (11.79 +/- 8.25) micromol/mol creatinine, (10.07 +/- 3.04) micromol/mol creatinine for the males with high and low exposure and of controls, respectively, (P < 0.05), and it was 84.35 micromol/mol creatinine, (21.27 +/- 5.89) micromol/mol creatinine, (14.43 +/- 2.58) micromol/mol creatinine for females with high and low exposure and of controls, respectively. The female workers exposed to arsenic had higher urinary 8-hydroxydeoxyguanine levels than males did (P < 0.05). The increased tendencies of urinary 8-hydroxydeoxyguanine levels with the organic arsenic concentration were found in workers (r(s) = 0.279, P = 0.019). CONCLUSION: Occupational individuals exposed to arsenic have obvious DNA oxidative damage, which is more severe in females. The difference of metabolism of arsenic may play a key role.

[Changes of the certain genotoxicities in workers occupationally exposed to arsenic].

OBJECTIVE: To study the changes of genotoxicities of workers occupationally exposed to arsenic in a mill of Yunnan Province. METHODS: The micronucleated cell and micronucleus frequency, comet rate and tail length of lymphocyte in comet assay from peripheral blood, urinary total and organic arsenic were detected and evaluated in 40 workers (exposure group), and also local people who did not contact with any poison obviously (control group). RESULTS: The micronucleated cell and micronucleus frequencies, the comet rate and tail length of lymphocyte in exposure groups were all more higher than those of controls (P < 0.01). The urinary total and organic arsenic concentrations in exposure groups were more higher than those of controls (all lower than 0.02mg/L for controls). The increased tendencies of micronucleated cells and micronucleus frequencies with the products of organic arsenic concentrations and service length were found in exposure groups(r(s) = 0.356, P = 0.024, r(s) = 0.347, P = 0.028). CONCLUSION indicated that arsenic could induce the damage of chromosome and DNA in lymphocyte of peripheral blood in workers occupationally exposed to arsenic.

[Study on the location on the nucleotide of DNA lesion detected by RDPCR].

OBJECTIVE: To simplify the establishing procedure of RDPCR and detect the DNA lesion on the precise position at the level of nucleic acid. METHODS: The TK6 cell was cultured and its genomic DNA was extracted and prepared to the single-stranded probes of the exon 2 of k-ras gene. The exon 2 of k-ras gene was amplified,called short fragment. The digestion of the genomic DNA and the short fragment were treated by the endonuclease HinfI. To the former, the products come from the every step of RDPCR were imaged after gel electrophoresis (GE) and the end products was taken coloration after southern hybridization with the single-stranded probes of the exon 2 of k-ras gene as well as were sequenced after re-amplified. To the latter, the genomic DNA were treated as the former except the GE. RESULTS: From the image of GE, the straps could be seen clearly that come from every step of amplifying of short fragments which were cleaved by the endonuclease HinfI in RDPCR. The clear hybridized bands caused by the products of RDPCR were seen at the expectant position. The sequencing analysis showed that the position was linked by the linker was just the restriction site of HinfI. CONCLUSION: Results indicated that RDPCR could be easily established by the short fragment method. This may be the first time detect the precise position of DNA lesion at the level of nucleic acid by RDPCR.

[Experiment research on the location of DNA lesion in the nucleic acid sequence].

OBJECTIVE: To research on establishing a method that can detect the DNA lesion at the level of nucleic acid. METHODS: The TK6 cell was cultured and treated, the genomic DNA was extracted, and the strand cleavage was induced by the endonuclease Hinf I. Then the genomic DNA was amplified by randomized terminal linker-dependent PCR (RDPCR), and hybridized by Southern hybridization with the single-stranded probes of the exon 2 of k-ras gene. The PCR products were sequenced. RESULTS: The clear hybridized band from the products of RDPCR was seen at the expectant position cut by Hinf I. The sequencing analysis showed that the position of DNA lesion linked by the linker was just the restriction site of Hinf I. CONCLUSION: It can be used to detect the DNA lesion at the level of nucleic acid sequence with the combination of sequence and RDPCR technologies.

The relationship between airborne fine particle matter and emergency ambulance dispatches in a southwestern city in Chengdu, China.

High levels of fine particulate matter (PM2.5) are known to cause adverse effects to human health. The goal of this study was to estimate the acute health effects of short-term exposure to ambient PM2.5 by analyzing cause-specific emergency ambulance dispatches as the endpoint in Chengdu, a city in Sichuan Province in southwest China. The ambient PM2.5 concentration of Chengdu reached 63 µg/m3 in 2015. Data related to the causes of specific emergency ambulance dispatches, air pollution, and meteorological conditions were collected from 2013 to 2015 (1095 days). A generalized additive model (GAM) was constructed to control the confounding conditions and to estimate the effects of PM2.5 on human health conditions. Emergency ambulance dispatches for all causes with (RR for lag0 = 1.0010, 95%CI: 1.0002, 1.0019) or without injuries (RR for lag0 = 1.0012, 95%CI: 1.0002, 1.0022), respiratory diseases (RR for lag0 = 1.0051, 95%CI: 1.0012, 1.0089), and cardiovascular diseases (RR for lag0 = 1.0041, 95%CI: 1.0009, 1.0074) were associated with ambient PM2.5 concentrations in Chengdu. In addition, the effects of PM2.5 were not confounded by ozone.