Short-term effects of heatwaves on clinical and subclinical cardiovascular indicators in Chinese adults: A distributed lag analysis

AIMS

Previous studies have related heat waves to morbidity and mortality of cardiovascular diseases; however, potential mechanisms remained limited. Our aims were to investigate the short-term effects of heat waves on a series of clinical/subclinical indicators associated with cardiovascular health.

METHODS

Our study used 80,574 health examination records from the Health Management Center of Nanjing Zhongda Hospital during the warm seasons of 2019-2021, including 62,128 participants. A total of 11 recognized indicators of cardiovascular risk or injury were assessed. Air pollution and meteorological data were obtained from the Nanjing Ecological Environment Bureau and the China Meteorological Data Network, respectively. Heat waves were defined as a daily average temperature over the 95th percentile for three or more consecutive days from May to September. We used a combination of linear mixed effects models and distributed lag nonlinear models to assess the lagged effects of heat waves on clinical and subclinical cardiovascular indicators. Stratified analyses based on individuals' characteristics, including gender, age, body mass index (BMI), diabetes, and hypertension, were also performed.

RESULTS

Heat waves were related to significant changes in most indicators, with the magnitude of effects generally peaking at a lag of 0 to 3 days. Moreover, the cumulative percentage changes over lag 0-7 days were -0.82 % to -2.55 % in blood pressure, 1.32 % in heart rate, 0.20 % to 2.66 % in systemic inflammation markers, 0.36 % in a blood viscosity parameter, 9.36 % in homocysteine, and 1.35 % to 3.25 % in injuring myocardial enzymes. Interestingly, females and males showed distinct susceptibilities in different indicators. Stronger effects were also found in participants aged 50 years or over, individuals with abnormal BMI status, and patients with diabetes.

CONCLUSION

Short-term exposure to heat waves could significantly alter clinical/subclinical cardiovascular indicator profiles, including blood pressure changes, increased heart rate, acute systemic inflammation, elevated blood viscosity, and myocardial injury.

The association between the essential metal mixture and fasting plasma glucose in Chinese community-dwelling elderly people

BACKGROUND

Epidemiological studies about the effect of essential metal mixture on fasting plasma glucose (FPG) levels among elderly people are sparse. The object of this study was to examine the associations of single essential metals and essential metal mixture with FPG levels in Chinese community-dwelling elderly people.

METHODS

The study recruited 2348 community-dwelling elderly people in total. Inductively coupled plasma-mass spectrometry was adopted to detect the levels of vanadium (V), selenium (Se), magnesium (Mg), cobalt (Co), calcium (Ca), and molybdenum (Mo) in urine. The relationships between single essential metals and essential metal mixture and FPG levels were evaluated by linear regression and Bayesian kernel machine regression (BKMR) models, respectively.

RESULTS

In multiple-metal linear regression models, urine V and Mg were negatively related to the FPG levels (β = - 0.016, 95 % CI: - 0.030 to - 0.003 for V; β = - 0.021, 95 % CI: - 0.033 to - 0.009 for Mg), and urine Se was positively related to the FPG levels (β = 0.024, 95 % CI: 0.014-0.034). In BKMR model, the significant relationships of Se and Mg with the FPG levels were also found. The essential metal mixture was negatively associated with FPG levels in a dose-response pattern, and Mg had the maximum posterior inclusion probability (PIP) value (PIP = 1.0000), followed by Se (PIP = 0.9968). Besides, Co showed a significant association with decreased FPG levels in older adults without hyperlipemia and in women.

CONCLUSIONS

Both Mg and Se were associated with FPG levels, individually and as a mixture. The essential metal mixture displayed a linear dose-response relationship with reduced FPG levels, with Mg having the largest contribution to FPG levels, followed by Se. Further prospective investigations are necessary to validate these exploratory findings.

The associations of non-essential metal mixture with fasting plasma glucose among Chinese older adults without diabetes

The evidence about the effect of non-essential metal mixture on fasting plasma glucose (FPG) levels among older adults without diabetes is limited. This study aims to estimate the individual and joint relationship between five non-essential metals and FPG levels in Chinese older adults without diabetes. This study included 2362 older adults without diabetes. Urinary concentrations of five non-essential metals, i.e., cesium (Cs), aluminum (Al), thallium (Tl), cadmium (Cd), and arsenic (As), were detected by inductively coupled plasma mass spectrometry (ICP-MS). The associations of single metals and the metal mixture with FPG levels were assessed using linear regression and Bayesian kernel machine regression (BKMR) models, respectively. Adjusted single-metal linear regression models showed positive associations of urinary Al (β = 0.016, 95%CI: 0.001-0.030) and Cs (β = 0.018, 95%CI: 0.006-0.031) with FPG levels. When comparing the 2th, 3th, and 4th quartiles of urine Cs to its 1th quartile, the significant associations between Cs and FPG levels were found and presented as an "inverted U" trend (βQ2 vs. Q1: 0.034; βQ3 vs. Q1:0.054; βQ4 vs. Q1: 0.040; all P<0.05). BKMR analyses showed urinary level of Cs exhibited an "inverted U" shape association with FPG levels. Moreover, the FPG levels increased linearly with the raised levels of the non-essential metal mixture, and the posterior inclusion probability (PIP) of Cs was the highest (0.92). Potential positive interaction of As and Cs on FPG levels was found in BKMR model. Stratified analysis displayed significant interactions of hyperlipidemia and urine Cs or Tl on FPG levels. An inverse U-shaped association between Cs and FPG was found, individually and as mixture. The FPG levels increased with the raised levels of the non-essential metal mixture, and Cs was the most contributor to FPG levels. Further research is required to confirm the correlation between non-essential metals and FPG levels and to clarify the underlying mechanisms.

Short-term effects of cold spells on hematocrit among adults in Nanjing, China: A distributed-lagged effect analysis

BACKGROUND

Previous studies have linked exposure to cold spells with cardiovascular diseases, however, underlying mechanisms remained to be understood. We aimed to explore the short-term effects of cold spells on hematocrit, a blood indicator associated with cardiovascular disease.

METHODS

Our study was performed among 50,538 participants (68,361 health examination records) who visited the health examination centers of Zhongda Hospital in Nanjing City, China, during the cold seasons from 2019 to 2021. Data on meteorology and air pollution were obtained from the China Meteorological Data Network and the Nanjing Ecological Environment Bureau, respectively. Cold spells in this study were defined as daily mean temperatures (Tmean) <3rd or 5th percentile with two or more consecutive days. Linear mixed-effect models combined with distributed lag nonlinear models were applied to estimate associations of cold spells with hematocrit.

RESULTS

Cold spells were found to be significantly correlated with increased hematocrit on lag 0 to 26 days. Moreover, the cumulative effects of cold spells on hematocrit remained significant at varying lag days. These single and cumulative effects were robust across different definitions of cold spells and conversions of hematocrit. For instance, cold spells (Tmean <3rd percentile) at lags 0, 0-1, and 0-27 days were significantly associated with 0.09 [95 % confidence interval (CI): 0.03, 0.15], 0.17 (95 % CI: 0.07, 0.28), and 3.71 (95 % CI: 3.06, 4.35) - unit (%) increases in original hematocrit, respectively. In subgroup analyses, stronger effects of cold spells on hematocrit were observed in females and participants aged 50 years or over.

CONCLUSION

Cold spells have significant immediate and longer-lagged effects (up to 26 days) on hematocrit. Females and individuals aged 50 years or over are more sensitive to cold spells. These findings might provide a new perspective for exploring the effects of cold spells on adverse cardiac events.

Ambient nitrogen dioxide and cardiovascular diseases in rural regions: a time-series analyses using data from the new rural cooperative medical scheme in Fuyang, East China

Most of studies relating ambient nitrogen dioxide (NO₂) exposure to hospital admissions for cardiovascular diseases (CVDs) were conducted among urban population. Whether and to what extent these results could be generalizable to rural population remains unknown. We addressed this question using data from the New Rural Cooperative Medical Scheme (NRCMS) in Fuyang, Anhui, China. Daily hospital admissions for total CVDs, ischaemic heart disease, heart failure, heart rhythm disturbances, ischaemic stroke, and haemorrhagic stroke in rural regions of Fuyang, China, were extracted from NRCMS between January 2015 and June 2017. A two-stage time-series analysis method was used to assess the associations between NO₂ and CVD hospital admissions and the disease burden fractions attributable to NO₂. In our study period, the average number (standard deviation) of hospital admissions per day were 488.2 (117.1) for total CVDs, 179.8 (45.6) for ischaemic heart disease, 7.0 (3.3) for heart rhythm disturbances, 13.2 (7.2) for heart failure, 267.9 (67.7) for ischaemic stroke, and 20.2 (6.4) for haemorrhagic stroke. The 10-μg/m³ increase of NO₂ was related to an elevated risk of 1.9% (RR: 1.019, 95% CI: 1.005 to 1.032) for hospital admissions of total CVDs at lag0-2 days, 2.1% (1.021, 1.006 to 1.036) for ischaemic heart disease, and 2.1% (1.021, 1.006 to 1.035) for ischaemic stroke, respectively, while no significant association was observed between NO₂ and hospital admissions for heart rhythm disturbances, heart failure, and haemorrhagic stroke. The attributable fractions of total CVDs, ischaemic heart disease, and ischaemic stroke to NO₂ were 6.52% (1.87 to 10.94%), 7.31% (2.19 to 12.17%), and 7.12% (2.14 to 11.85%), respectively. Our findings suggest that CVD burdens in rural population are also partly attributed to short-term exposure to NO₂. More studies across rural regions are required to replicate our findings.

Selenium attenuates the association of co-exposure to arsenic, cadmium, and lead with cognitive function among Chinese community-dwelling older adults

The effects of interactions between the toxic and essential metal mixtures on cognitive function are poorly understood. This study aims to identify the joint association of arsenic (As), cadmium (Cd), and lead (Pb) with cognitive function in older adults and the moderating role of selenium (Se), zinc (Zn), and copper (Cu) in this association. This study included 1000 community-dwelling older adults. Cognitive function was assessed by the Mini-Mental State Examination (MMSE). Blood concentrations of As, Cd, Pb, Se, Zn, and Cu were measured using inductively coupled plasma mass spectrometry. Linear regression and Bayesian kernel machine regression (BKMR) models were applied to assess the individual and joint associations of As, Cd, and Pb with cognitive function and to examine whether Se, Zn, and Cu (individually and as a mixture) modified these associations. In the adjusted single-metal models, both Cd (β = - 0.37, 95% CI: - 0.73 to - 0.01) and Pb (β = - 0.44, 95% CI: - 0.86 to - 0.02) were associated with MMSE scores, while Se (β = 0.71, 95% CI: 0.30 to 1.13) exhibited a positive relationship with MMSE scores. Univariate exposure-response functions from BKMR models showed similar results. Moreover, the toxic metal mixture (As, Cd, and Pb) exhibited a significant negative association with MMSE scores in a dose-response pattern, with Pb being the greatest contributor within the mixture. The negative association of Pb alone or the toxic metal mixture with MMSE scores became weaker at higher concentrations of Se within its normal range, especially when Se levels were greater than the median (89.18 μg/L). Our findings support that Se can attenuate the negative associations of exposure to single Pb or the As, Cd, and Pb mixtures with cognitive function. Future prospective studies are needed to replicate our findings.

The association between essential trace element mixture and atherosclerotic cardiovascular disease risk among Chinese community-dwelling older adults

The evidence about the association of the essential trace element (ETE) mixture with atherosclerotic cardiovascular disease (ASCVD) amongst older adults is limited. This study aims to evaluate the associations of single ETEs and the ETE mixture with the 10-year ASCVD risks and its predicting factors in Chinese community-dwelling older adults. A total of 607 community-dwelling older adults were included in this study. Blood levels of vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), and selenium (Se) were assessed by inductively coupled plasma mass spectrometry. The predicted 10-year ASCVD risk was calculated using the Prediction for ASCVD Risk in China (China-PAR) equations. Traditional linear regressions and Bayesian kernel machine regression (BKMR) were used to assess the associations of single ETEs and the ETE mixture with the 10-year ASCVD risks and its predicting factors such as systolic blood pressure (SBP), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), diabetes, and waist circumference (WC). In linear regression models, blood Cr levels were negatively associated with the 10-year ASCVD risks after adjustment for covariates (β =  - 0.07, 95% CI =  - 0.11 ~  - 0.03); The 3th quartile (Q3) of Se levels was also associated with a lower 10-year ASCVD risks when compared with the lowest quartile (Q1) of Se levels (β_Q3 vs. _Q1: - 0.12, 95% CI =  - 0.22 ~  - 0.02). In BKMR models, the negative associations of Cr and Se with the 10-year ASCVD risks were observed. Higher blood levels of ETE mixture were associated with decreased 10-year ASCVD risks in a dose-response pattern, with Cr having the highest value of the posterior inclusion probability (PIP) within the mixture. Furthermore, a positive association between Cr and HDL-C and a negative association between Se and SBP were found in both linear regression and BKMR models. Cr and Se were negatively associated with the 10-year ASCVD risks, individually and as a mixture. ETE mixture showed a linear dose-response association with decreased 10-year ASCVD risks, with Cr being the most important component within the mixture. The negative association of the ETE mixture with the 10-year ASCVD risks may be attributed to Cr and Se, mainly mediated by HDL-C and SBP, respectively. Further cohort studies are needed to clarify this association.

[The citation analysis of the articles published in Chinese Journal of Otorhinolaryngology Head and Neck Surgery from 2009 to 2019]

Objective: To analyze the citation of articles in Chinese Journal of Otorhinolaryngology Head and Neck Surgery, and to explore the strategy for running scientific journals. Methods: Using the Citation Database of Chinese Biomedical Journals, the citations of articles in this journal from 2009 to 2019 were statistically analyzed, and the characteristics of highly cited articles were analyzed. Results: From 2009 to 2019, Chinese Journal of Otorhinolaryngology Head and Neck Surgery published 2 814 papers. Cited papers accounted for 75.69% of all papers, and each paper was cited 7.24 times. The citation rate of published papers was consistent with the variation trend of citation frequency. Non treatises such as guide consensus and original articles for special issues were cited better. There was no obvious correlation between paper funding and citation. Conclusion: Improving the content quality and optimizing the column setting are important measures to enhance the influence of scientific journals.

The association between essential trace element mixture and cognitive function in Chinese community-dwelling older adults

BACKGROUND

The evidence about the effect of essential trace element (ETE) mixture on cognitive function amongst older adults is limited. This study aims to evaluate the associations of single ETEs and ETE mixture with cognitive function using a representative sample of community-dwelling older adults in China.

METHODS

A total of 3814 older adults were included in the study. Urinary concentrations of selenium (Se), vanadium (V), cobalt (Co), strontium (Sr), and molybdenum (Mo) were detected by inductively coupled plasma mass spectrometry. Cognitive function in older adults was assessed using the Chinese version of the Mini-Mental State Examination (MMSE). Linear regression and Bayesian kernel machine regression (BKMR) were performed to explore the associations of single ETEs and ETE mixture with cognitive function, respectively.

RESULTS

Linear regression showed that urinary levels of Se and V were positively associated with MMSE scores in the adjusted single-element models. BKMR also showed marginally positive associations of Se and V with MMSE scores. Moreover, higher urinary levels of ETE mixture were significantly associated with increased MMSE scores in a dose-response pattern, and Se was the most important contributor within the mixture. Both Se and V demonstrated positive additive effects on the associations of other ETEs with MMSE scores, whereas Co had a negative additive effect.

CONCLUSIONS

V and Se are positively associated with cognitive function, individually and as a mixture. ETE mixture exhibits a linear dose-response association with improved cognitive function, with Se being the most important component within the mixture. Mixture analyses rather than single ETE analyses may provide a real-world perspective on the relationship between ETE mixture and cognitive function. Further cohort studies are needed to clarify the association of multiple ETEs with cognitive function.

The associations between urinary metals and metal mixtures and kidney function in Chinese community-dwelling older adults with diabetes mellitus

BACKGROUND

Previous studies have found associations between single toxic metals, such as arsenic and cadmium, and kidney function in adults with diabetes. However, studies with regards to other metals and metal mixtures are still limited.

OBJECTIVE

Our study aimed to investigate the associations between urinary concentrations of 5 selected metals and metal mixtures and kidney function using a sample of older adults with diabetes mellitus in Chinese communities.

METHODS

In a sample of older adults (n = 5186), 592 eligible subjects were included in this study. Urinary concentrations of 5 metals, i.e., arsenic (As), cadmium (Cd), vanadium (V), cobalt (Co), and thallium (Tl), were measured by inductively coupled plasma mass spectrometer (ICP-MS). Estimated glomerular filtration rate (eGFR) was calculated and dichotomized into indicator of chronic kidney disease (CKD). Logistic analysis and Bayesian kernel machine regression (BKMR) were used to explore the associations between single metals and metal mixtures and CKD, respectively.

RESULTS

Urinary levels of As and V were positively correlated with CKD (OR=2.37, 95% CI: 1.31-4.30 for As; OR=2.24, 95% CI: 1.25-4.03 for V), when compared the 4th quartile with the 1st quartile. After adjustment for potential confounders, the significant association between As and CKD still existed (OR=2.73, 95% CI: 1.23-6.07). BKMR analyses showed strong linear positive associations between As and V and CKD. Higher urinary levels of the mixture were significantly associated with higher odds of CKD in a dose-response pattern. As and V showed the highest posterior inclusion probabilities.

CONCLUSION

Urine As and V were positively associated with CKD in older adults with diabetes mellitus, separately and in a mixture. The metals mixture showed a linear dose-response association with the odds of CKD. The analyses of mixtures, rather than of single metals, may provide a real-world perspective on the relationship between metals and kidney function.

Bioaccumulation and translocation of trace elements in soil-irrigation water-wheat in arid agricultural areas of Xin Jiang, China

Pollution resulting from toxic trace elements is an increasing concern around the world especially in developing countries such as China. Rapid industrialisation, urbanisation and agricultural development are the dominant sources of anthropogenic contamination contributed to an increased potential toxicity of trace elements in the irrigation water-soil-food chain. Xin Jiang in China is a reserved cultivated land development area that could provide the most extensive strategic support for food production and arable land security in China. Thus, it is crucial to investigate the bioaccumulation and translocation of trace elements in order to assess the ecological and human health risks in the traditional oasis system of the agricultural areas in Bay Cheng County, Xin Jiang. This study analysed the levels of trace elements in different layers of the soil, the irrigation water and the wheat plants, and the relationships among them. The results indicated that cadmium (Cd) and chromium (Cr) were the primary pollutants in soils and wheats respectively, and they fell into the serious pollution category. However, no trace elements over the pollution limits were detected in irrigation water. The maximum values of trace elements appeared in the soil layers at 5-10 cm and 10-15 cm. The pollution levels of trace elements in the soil layers were found at 0-5 cm and 0-20 cm, which were higher than those at 20-80 cm. In wheat, high amounts of absorption for Se, Cr, Zn and Cu, but low for Pb were detected in different parts of a plant. The roots of wheats were more eco-toxic to Cd, Co and Pb than other tissues, indicating that roots were more effective at absorbing Cd, Co and Pb, as these metals are usually toxic in the soil. Se, Cu and Zn showed a higher ability of being transferred from soils to the edible parts of crops. The bio-transfer factors of Zn, Mo, Cu, Mg and Mn were considerably higher than those of other elements. The average cancer risk of As, Cd, Co, Ni and TCR in wheat grains exceeded the safety reference limit (1 × 10^-4). For the exposed population, Cr in wheat was the major contributor to total cancer risk. The average values of HQ of Cr, Mn and As, and total non-cancer risk index exceeded the corresponding effective safe reference doses (HQ > 1).

Levels and determinants of urinary phthalate metabolites in Chinese community-dwelling older adults

BACKGROUND

Biomonitoring studies have demonstrated extensive exposure of infants, children, and pregnant women to phthalates, but data on phthalate exposure and their determinants in Chinese older adults remain insufficient. This study aims to assess urinary phthalate metabolite levels, individual and cumulative exposure risk, and their determinants in Chinese community-dwelling older adults.

METHODS

A total of 987 individuals aged 60 years or over were included in this study. The urinary levels of seven phthalate metabolites were measured using high-performance liquid chromatography-tandem mass spectrometry. The estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) of phthalates were calculated based on urinary metabolite levels. The associations between phthalate metabolite levels and potential determinants were examined using multiple linear regressions.

RESULTS

Detection rates of seven phthalate metabolites from the study population ranged from 63.83% to 99.39%. The highest median concentration was 43.64 μg/L (42.59 μg/g creatinine) for mono-butyl phthalate (MBP). The highest median EDI was 1.55 μg/kg-bw/day for diethyl phthalate (DBP). Nearly 5% of participants had high HI values exceeding 1, mainly attributed to DBP and di-2-ethylhexyl phthalate (DEHP). Furthermore, we found that females, higher body mass index (BMI), smoking, having two or more chronic diseases, and vegetable-based diets were significantly associated with higher levels of parts of phthalate metabolites. More interestingly, higher urine levels of high-molecular-weight (HMW) phthalate metabolites and lower urine levels of low-molecular-weight (LMW) phthalate metabolites were found in rural older adults than in urban older adults.

CONCLUSIONS

Chinese community-dwelling older adults are extensively exposed to phthalates, especially to DBP and DEHP. More attention should be paid to urban-rural differences in exposure to HMW and LMW phthalates and to phthalate exposure among older adults with overweight/obesity, females, and individuals who are current heavy smokers, have two or more chronic diseases, and consume vegetable-based diets.

Urban-rural differences in the effect of empty-nest on mental health and behaviors of Chinese older population

This study aimed to comprehensively analyze the effect of empty-nest on mental health and behaviors of the older population and explore the urban-rural differences. Data from the Cohort of Older People Health and Environment Controllable Factors were used, including 1071 older people aged 60 or over from a rural and an urban. Mental health, daily life behaviors, chronic physical diseases, and activities of daily living were evaluated. Logistic regression was used. The prevalence of empty-nest in older people was 55.0% in urban and 58.7% in rural. The empty-nest older people in urban were more likely to participate in physical exercise (OR[95%CI]: 1.55[1.03-2.31]), while the empty-nest older people in rural had lower rate of smoking (OR[95%CI]: 0.46[0.28-0.76]) and religious belief (OR[95%CI]: 1.61[1.01-2.58]), and higher prevalence of depression (OR[95%CI]: 1.55[1.03-2.35]) and higher level of total cholesterol (OR[95%CI]: 1.51[1.03-2.19]) compared with the non-empty-nest older people. In conclusion, the prevalence of empty-nest in older people was high both in rural and urban in China. Empty-nest exerts greater influences on the older people in rural than in urban, which should be given more attention, especially the depression and high total cholesterol.

The levels of phthalate exposure and associations with obesity in an elderly population in China

BACKGROUND

Few epidemiological studies on the correlation between phthalate exposure and elderly obesity in China are available. The purpose of the present study is to assess phthalate exposure levels and explore the connections between exposure to phthalates and obesity using a sample of Chinese community-dwelling elderly individuals.

METHODS

Data were acquired from the baseline survey of the Cohort of Health of Elderly and Controllable Factors of Environment, which was established in Lu'an, Anhui province, China, from June to September in 2016. Urine samples were obtained to analyze the concentrations of seven phthalate metabolites, utilizing a high-performance liquid chromatography-tandem mass spectrometry method. General obesity was determined based on body mass index, and abdominal obesity based on waist circumference. Binary logistic regression models were utilized to analyze the associations of creatinine-corrected phthalate metabolite concentrations (categorized into quartiles) with general and abdominal obesity in elderly people. Moreover, a stratified analysis was performed to explore the difference between genders.

RESULTS

Of 942 elderly individuals, 52.9% were defined as generally obese and 75.5% as abdominally obese. The detection rates of seven phthalate metabolites ranged from 90.07% to 99.80%. The highest median concentration was 44.08 μg/l (for MBP), and the lowest was 0.55 μg/l (for MEHP). The level of exposure to LMW(low-molecular-weight) PAEs is higher than that to HMW(high-molecular-weight) PAEs. After adjustment for confounding variables, we found a significant association between urinary MEOHP (mono-2-ethyl-5-oxohexyl phthalate), MEHP (mono-2-ethylhexyl phthalate), MBP (mono-n-butyl phthalate), MEP (mono-ethyl phthalate), and MMP (mono-methyl phthalate) levels and general obesity. MBP levels were also correlated with abdominal obesity. When stratified by gender, higher urinary levels of MEOHP, MBP, MEP, and MMP were associated with general obesity in males, whereas MBP and MMP levels were eminently correlated with general obesity in females. Higher urinary MBP levels were associated with increased abdominal obesity rates in males, but not in females.

CONCLUSIONS

In conclusion, higher phthalate metabolite concentrations were correlated with obesity in the elderly. Moreover, a gender difference was observed in these associations.

Weight changes since age 20 and cardiovascular risk factors in a middle-aged Chinese population

Background

Little is known about the association between weight changes and adverse health outcomes among Chinese adults.

Methods

A total of 1715 Chinese adults, 45-60 years of age, have been recruited to participate in the Hefei Nutrition and Health Study started in 2012. Multivariate logistic regression analysis was performed to determine the association of weight changes since age 20 (loss ≥5.0 kg; maintain [±4.9 kg]; gain 5.0-9.9 kg; gain ≥10.0 kg) with cardiovascular risk factors.

Results

Men who gained 10.0 kg or more had increased risks of hypertension (odds ratios (OR) = 3.07; 95% CI: 1.98-4.76), impaired fasting glucose (OR = 1.74; 95% CI: 1.02-2.97), reduced high-density lipoprotein (HDL) cholesterol levels (OR = 2.77; 95% CI: 1.42-5.40) and elevated triglyceride levels (OR = 5.72; 95% CI: 2.94-11.12). Women who gained 10.0 kg or more had increased risks of hypertension, elevated low-density lipoprotein (LDL) cholesterol levels and elevated triglycerides levels of 2.01(95% CI: 1.18-3.42), 3.40 (95% CI: 1.18-9.82) and 5.60 (95% CI: 1.59-19.61), respectively.

Conclusion

Weight gain during adulthood was associated with increased risks of high triglycerides, hypertension, impaired fasting glucose and risk of reduced HDL cholesterol in men. Furthermore, weight gain was a predictor of high-risk triglycerides, hypertension and elevated LDL cholesterol in women.

[Adsorption and Mechanism of Arsenic by Natural Iron-containing Minerals]

Natural iron-containing minerals present in the geosphere in the form of crystalline minerals can be used as adsorption material for removal of arsenic from wastewater and remediation of arsenic-contaminated soils. In this paper, the adsorption and desorption of arsenic onto different iron-containing materials including hematite, limonite, siderite, ilmenite, magnetite, Fe₂O₃, Fe₃O₄, and Fe-Mn binary oxide (FMBO) were studied in laboratory experiments. The mechanism of arsenic adsorption was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). The results showed that arsenic adsorption is fitted by pseudo-second-order kinetics and the Langmuir isotherm model for almost all adsorbents, suggesting monolayer adsorption of arsenic onto the minerals. The sorption efficiency and capacity of arsenic by FMBO are much higher than those of other materials. Furthermore, limonite has high sorption efficiencies for both As(Ⅲ) and As(Ⅴ) among the natural iron-containing minerals, and their adsorption capacities are 3.96 mg·g^-1 and 2.99 mg·g^-1, respectively. The XRD results showed that natural limonite contains a large number of weak crystalline mineral components such as goethite, which can provide relatively abundant arsenic adsorption sites. Thus, limonite appears to be the most suitable natural mineral for arsenic adsorption.

Difference of trace element exposed routes and their health risks between agriculture and pastoral areas in Bay County Xinjiang, China

The concentration level related to toxicities of trace elements in drinking water, rice, wheat flour, and their associated negative impacts on human health have become an emergent issue in China. Because Xinjiang is the largest province in China with the majority of arable pasture land available for cultivation, it is important to analyze the concentrations of trace elements in relation to their toxicities in water, rice, and wheat flour and to investigate the health risk differences between agricultural and pastoral areas in Bay County, Xinjiang. The study results showed that (1) metal concentrations from drinking water, rice, and wheat flour were within the permissible limits; (2) concentration levels of trace elements and their total risk from drinking water and rice were higher in the agricultural areas than those in the pastoral areas, whereas concentration levels of trace elements and their total risk from wheat flour were higher in the pastoral areas than those in the agricultural areas; (3) the concentration level of the trace elements in rice were higher than in the wheat flour, but the risk from the wheat flour was higher than the risk from rice; (4) total non-cancer risk from the flour (HI_f) in both areas exceeded the respective safe reference doses; (5) total cancer risk from the wheat flour, rice, and water exceeded the safety limit (1 × 10^-4); (6) for the exposed population, arsenic was suggested as the most evident pollutant leading to carcinogenic concerns regarding the water, rice, and wheat flour; (7) the risk index from the wheat flour made up the highest percentage both in the total cancer risk and the non-cancer risk, followed by rice and then water; and (8) the human health risk was attributed to influence from the local environment in the agriculture areas, while it was attributed to the external environment in the pastoral areas. Graphical abstract.

Adhering to a vegetarian diet may create a greater risk of depressive symptoms in the elderly male Chinese population

BACKGROUND

A vegetarian diet may be a risk factor for depression, but this relationship was unclear in the elderly Chinese population.

METHODS

Self-report data were gathered from 1051 elderly persons using the Cohort of Elderly Health and Environment Controllable Factors, which was created in West Anhui, China. The depressive symptoms were set as binary, ordinal, and continuous outcomes, respectively, whereas the dietary structures were computed as an ordinal variable and a dummy variable. Multiple logistic regression, ordinal regression, and linear regression were used to assess the relationship by adjusting the potential confounding variables with p-values of <0.1 in univariate analysis.

RESULTS

The elderly participants who had a vegetable-based diet had the highest GDS scores of 8.78 ± 6.894 (p = 0.001) and the highest rate of depression (32.9%, p = 0.003). After adjustment for the potential confounders, elderly men who had a vegetable-based diet had a higher rate of depression (OR[95%CI]: 1.62[1.07-2.46], 4.71[1.38-16.03]), more severe symptoms of depression (OR[95%CI]: 8.85[2.94-34.12]), and higher GDS scores (β[95%CI]: 1.46[0.70-2.22], 2.97[1.28-4.67]) than male participants who had a meat-based diet, but this was not the case in women.

LIMITATIONS

All data were self-reported. The study lacked quantitatively evaluated dietary intake. The duration of the current dietary structures and comorbidities were not reported. The cross-sectional study made the causal role uncertain.

CONCLUSIONS

Vegetarian diets may pose a greater risk of depressive symptoms among the elderly Chinese population, especially elderly men. Given the cross-sectional nature of this study, the causal role was uncertain. Further prospective studies, in particular among elderly women, are needed.

Accumulation of steroid hormones in soil and its adjacent aquatic environment from a typical intensive vegetable cultivation of North China

Steroid hormones released from manure agricultural application are a matter of global concern. The residual levels of steroid hormones were studied in a typical intensive vegetable cultivation area in northeast China, with a long history of heavy manure application. Seven steroids (estrone, 17α-estradiol, 17β-estradiol, estriol, testosterone, androstendione and progesterone) were analyzed from soil sampled from vegetable greenhouses, from sediments and water from the adjacent drainage ditch and from the groundwater. The results showed that target steroids were detected in the soil samples, with detection frequencies varying from 3.13 to 100%. The steroid concentrations varied substantially in soils, ranging from below the detection limit to 109.7μg·kg(-1). Three steroids-progesterone, androstendione and estrone-were found to have relatively high residue concentrations in soil, with maximum concentrations of 109.7, 9.83 and 13.30μg·kg(-1), respectively. In adjacent groundwater, all the steroids, with the exception of estrone, were detected in one or more of the 13 groundwater samples. The concentrations of steroids in groundwater ranged from below the method detection limit to 2.38ng·L(-1). Six of the seven (excluding androstendione) were detected in drainage ditch water samples, with concentrations ranging from below the detection limit to 14ng·L(-1). Progesterone, androstendione and estrone accumulated relatively easily in soils; their concentrations in groundwater were lower than those of other steroids. The concentrations of testosterone and estriol were relatively low in soil, while in groundwater were higher than those of other steroids. The residual levels of steroids in soil and groundwater showed a clear spatial variation in the study area. The residual levels of steroid hormones in soil varied substantially between differently planted greenhouses.

Prevalence of suicide attempts among college students in China: a meta-analysis

BACKGROUND

Suicide is the leading cause of death among 15-34 year olds in China, but no national data are available on the suicide and suicide attempts rates of college students, a sub-group of youth with 23 million. Several studies have reported the prevalence of suicide attempts among college students, however, no meta-analysis pooling the prevalence of suicide attempts is found.

OBJECTIVE AND METHODS

This study aims to estimate the pooled prevalence of suicide attempts among college students in China. The relevant studies up to August 2014 were systematically searched via electronic databases (PubMed-Medline, Embase, Chinese Wanfang database, Chinese National Knowledge Infrastructure and Chinese VIP database). We only selected original articles that either reported the prevalence of suicide attempts or sufficient data for calculating the prevalence.

RESULTS

A total of 29 eligible studies, with 88,225 college students, were finally included. The maximum and minimum reported prevalences of suicide attempts among college students in China were 0.4% and 10.5%, respectively. The pooled prevalence of suicide attempts was 2.8% (95%CI: 2.3%-3.3%). Subgroup analyses showed that the pooled estimate of prevalence of life time suicide attempts was 2.7% (95%CI: 2.1%-3.3%), and 12-month suicide attempts was 2.9% (95%CI: 2.0%-3.8%). The prevalence for males was 2.4% (95%CI: 1.8%-3.0%), and for females was 2.7% (95%CI: 1.9%-3.7%). The prevalences among college students in grade 1 through 4 were 2.8% (95%CI: 1.7%-3.8%), 1.8% (95%CI: 1.2%-2.3%), 2.0% (95%CI: 0.8%-3.1%), and 2.9% (95%CI: 0.1%-6.7%), respectively. The prevalences among college students from rural and urban areas were 5.1% (95%CI: 2.8%-7.5%) and 3.7% (95%CI: 1.4%-5.9%), respectively.

CONCLUSIONS

2.8% prevalence of suicide attempts and more than 600,000 suicide attempters among college students indicate that suicide attempt among college students is an important public health problem in China. More attention should be paid to the current situation.

Prevalence of suicide attempts among college students in China: a meta-analysis

BACKGROUND

Suicide is the leading cause of death among 15-34 year olds in China, but no national data are available on the suicide and suicide attempts rates of college students, a sub-group of youth with 23 million. Several studies have reported the prevalence of suicide attempts among college students, however, no meta-analysis pooling the prevalence of suicide attempts is found.

OBJECTIVE AND METHODS

This study aims to estimate the pooled prevalence of suicide attempts among college students in China. The relevant studies up to August 2014 were systematically searched via electronic databases (PubMed-Medline, Embase, Chinese Wanfang database, Chinese National Knowledge Infrastructure and Chinese VIP database). We only selected original articles that either reported the prevalence of suicide attempts or sufficient data for calculating the prevalence.

RESULTS

A total of 29 eligible studies, with 88,225 college students, were finally included. The maximum and minimum reported prevalences of suicide attempts among college students in China were 0.4% and 10.5%, respectively. The pooled prevalence of suicide attempts was 2.8% (95%CI: 2.3%-3.3%). Subgroup analyses showed that the pooled estimate of prevalence of life time suicide attempts was 2.7% (95%CI: 2.1%-3.3%), and 12-month suicide attempts was 2.9% (95%CI: 2.0%-3.8%). The prevalence for males was 2.4% (95%CI: 1.8%-3.0%), and for females was 2.7% (95%CI: 1.9%-3.7%). The prevalences among college students in grade 1 through 4 were 2.8% (95%CI: 1.7%-3.8%), 1.8% (95%CI: 1.2%-2.3%), 2.0% (95%CI: 0.8%-3.1%), and 2.9% (95%CI: 0.1%-6.7%), respectively. The prevalences among college students from rural and urban areas were 5.1% (95%CI: 2.8%-7.5%) and 3.7% (95%CI: 1.4%-5.9%), respectively.

CONCLUSIONS

2.8% prevalence of suicide attempts and more than 600,000 suicide attempters among college students indicate that suicide attempt among college students is an important public health problem in China. More attention should be paid to the current situation.

Spatial and seasonal variations of the air pollution index and a driving factors analysis in china

In this study, the daily air pollution index (API) of 110 cities based on ground monitoring was conducted on the 2011 data set from the Ministry of Environmental Protection of China. The pollutant concentrations, seasonal variations, and spatial autocorrelations were evaluated. The results show that the major principal pollutants in China are inhalable particles. In addition, the total number of clean days (API ≤ 50) is apparently smaller in the northern cities than in the southern cities as a result of fuel utilization and large-scale organized central heating. Seasonally, air pollution is most severe in winter and is caused by low-frequency rainfall, strong northwest winds, dry climate, and high energy consumption; this is followed by spring, which is a season of frequent sandstorms. According to spatial autocorrelation analysis, clusters with high API value agglomeration (High-High clusters) are mainly concentrated in the middle and northern parts of China, whereas clusters with low API agglomeration (Low-Low clusters) are principally concentrated in the southern parts of China due to a favorable climate and abundant rainfall. Meteorological data, including wind speed and temperature, have great impacts on API. The air quality effects of industrial structure, energy use, urban greening, and traffic congestion were also analyzed. With the ecological function of purifying the air, industries that use natural resources and urban greening could help to reduce API, whereas secondary industry and gas use, which have a positive coefficient, increase the API value. The risk of exposure to poor air quality is largest in the winter, smallest in the summer, and remains relatively unchanged in the spring and autumn.

Correlations between psychological symptoms and social relationships among medical undergraduates in Anhui Province of China

OBJECTIVES

To assess the prevalence of psychological symptoms (depression, anxiety) among Chinese medical students and to find the possible relationships between psychological symptoms and social relationships.

METHODS

A sample of 10,140 medical students was investigated with a structured questionnaire, that included the Beck Depression Inventory, Beck Anxiety Inventory, Social Support Rating Scale, and Family APGAR Index (adaptability, partnership, growth, affection, resolve).

RESULTS

The present study revealed that 16.8% of the medical students suffered from depressive symptoms and 14.1% from anxiety symptoms. Female students were more likely to have anxiety, the second-year students had higher levels of psychological symptoms than the first-year students. Likewise, significant differences were found among college, satisfaction of specialty, and economic condition of the family in anxiety and depression symptoms. Social support, family function, and all dimensions were significantly negatively associated with depression and anxiety symptoms. Multivariable ordinal logistic regression showed that less social support, poor family function, the second-year students, and unsatisfactory specialty were associated with more psychological symptoms, after adjusting the effects of sex, age, and college.

CONCLUSIONS

Medical students have a relatively high level of depression and anxiety symptoms. These findings support the hypothesis that if medical students are better supported and cared for, negative psychosocial consequences might be prevented or at least reduced.

Bioaccessibility and risk assessment of cadmium from uncooked rice using an in vitro digestion model

Cadmium (Cd)-contaminated rice is one of the most important sources of cadmium exposure in the general population from some Asian countries. This study was conducted to assess cadmium exposure from uncooked rice in rural mining areas based on the bioaccessible fraction of cadmium using an in vitro digestion model. The biotoxic effects of cadmium in uncooked rice from mining areas were much higher than those in the control area, based not only on their higher total concentration (52.49 vs. 7.93 μg kg(-1)), but also on their higher bioaccessibility (16.94% vs. 2.38%). In the mining areas, the bioaccessible fraction of cadmium in uncooked rice has a significant positive correlation with the total concentration of cadmium in rice and there was quarterly unsafe rice to the public in the mining areas. The results indicated that the in vitro digestion model could be a useful and economical tool for providing the solubilization or bioaccessibility of uncooked rice in the mining area. The results could be helpful in conducting future experiments of cooked rice in the vitro model.

[Remediation Pb, Cd contaminated soil in lead-zinc mining areas by hydroxyapatite and potassium chloride composites]

The composite agents containing potassium chloride (KCl) and Hydroxyapatite (HA) were used to remediate the lead and cadmium contaminated soil in Fenghuang lead-zinc mining-smelting areas, Hunan province. The objective of this study was to identify and evaluate the influence of Cl- to the fixing efficiency of Pb and Cd by HA. Two types of contaminated soil (HF-1, HF-2) were chosen and forty treatments were set by five different Hydroxyapatite (HA) dosages and four different Cl- dosages. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the results. It showed that HA could efficiently fix the Pb and Cd from TCLP form. The maximum Pb-fixing efficiency and Cd-fixing efficiency of two types of soil were 83.3%, 97.27% and 35.96%, 57.82% when the HA: Pb: KCl molar ratio was 8: 1: 2. Compared to the fixing efficiency without KCl, KCl at the KCl: Pb molar ratio of 2 improved Pb-fixing efficiency and Cd-fixing efficiency by 6.26%, 0.33% and 7.74%, 0.83% respectively when the HA: Pb molar ratio was 8. Generally, Cl- can improve the Pb/Cd-fixing efficiency in heavy metal contaminated soil by Hydroxyapatite.

[Spatial distribution and ecological significance of heavy metals in soils from Chatian mercury mining deposit, western Hunan province]

Ores, waste tailings and slag, together with three typical soil profiles (natural soil profiles far from mine entrance and near mine entrance, soil profile under slag) in Chatian mercury mining deposit (CMD), western Hunan province were sampled and their concentrations of mercury (Hg), arsenic (As), lead (Pb), cadmium (Cd), zinc (Zn) were determined by HG-ICP-AES and ICP-MS. Enrichment factor and correlation analysis were taken to investigate the origins, distribution and migration of Hg, as well as other heavy metals in the CMD. The results show that Hg is enriched in the bottom of the soil profile far from mine entrance but accumulated in the surface of soil profiles near mine entrance and under slag. The soil profiles near mine entrance and under slag are both contaminated by Hg, while the latter is contaminated more heavily. In the soil profile under slag, Hg concentration in the surface soil, Hg average concentration in the total profile, and the leaching depth of soil Hg are 640 microg x g(-1), (76.74 +/- 171.71) microg x g(-1), and more than 100 cm, respectively; while 6.5 microg x g(-1), (2.74 +/- 1.90) microg x g(-1), and 40 cm, respectively, are found in the soil profile near mine entrance. Soil in the mercury mine area is also polluted by Cd, As, Pb, Zn besides metallogenic element Hg, among which Cd pollution is relatively heavier than others. The mobility of the studied heavy metals in soil follows the order as Hg > Cd > As > Zn approximately equal to Pb. The leaching depth of the heavy metals is influenced by total concentration in the surface soil and soil physico-chemical parameters. The origins, distribution and migration of heavy metals in soil profile in the mining area are related to primary geological environment, and strongly influenced by human mining activities.

Depressive symptoms in aged Chinese patients with silicosis

OBJECTIVES

To investigate the prevalence of depressive symptoms in patients with silicosis and its determinants.

METHODS

A cross-sectional cohort study was performed. About 121 patients with silicosis randomly selected from a case registry of a non-ferrous metal company and 110 controls completed the questionnaires of sociodemographic variables, Beck depression inventory (BDI) and lung function test. chi(2) test was performed to compare the prevalence of depressive symptoms between two groups. The relationship between the variables and depressive symptoms in patients with silicosis was assessed by performing the logistic regression analysis.

RESULTS

Prevalence of depressive symptoms in patients with silicosis was 27.3%, which was higher than the figure 7.3% in controls (chi(2)=15.8, p<001). Severe respiratory symptoms, severe impaired physical function, FEV(1) <50% predicted and (FVC)% predicted less than mean were significantly associated with the depressive symptoms (Odds ratio [OR]=4.6, 5.9, 3.0 and 5.2, respectively).

CONCLUSION

High prevalence of depressive symptoms was found in patients with silicosis. Respiratory symptoms, physical function and pulmonary functions were associated with depressive symptoms. Our findings provide evidence for physicians to screen for depressive symptoms in patients with silicosis.

[Lead uptake by plant in soil-plant system at lead-zinc deposit area of western Hunan province]

Contents of lead in several crops as well as its uptake and distribution by paddy in typical lead-zinc deposit area of western Hunan province were studied based on field systematic sampling and laboratory analysis. The average concentration of lead in rice, maize and soy bean in the deposit was 2.4, 1.2 and 3.3 times higher than that in control area, respectively, suggesting that crops in the deposit were heavily contaminated by the element. Significant difference of the lead concentrations in crops was found among different crop species and different organs of the same crops. The average concentration of lead followed the trend: soy bean > rice > maize (among crop species), and root > haulm > seed (among organs). Paddy root exhibited strong binding and tolerant capacity to lead. Correlation analysis indicated that soil lead was main retention in paddy root, whereas the gaseous lead might be the main source for lead in the aerial part of crop. Heavy metals such as Hg, Cd as well as Pb co-enriched in crops, therefore the mechanism and health risk of the combined pollution of heavy metals in the deposit crops should be paid attention to.

[Pollution characteristics analysis of Hg, Pb and As in soils of nonferrous metal mine area by the BCR and HG-ICP-AES technique]

A method for the determination of Hg, Pb and As concentrations in soil and sediment samples by the BCR and HG-ICP-AES technique was described. Under the optimum experimental conditions and instrumental operation parameters, the detection limits of Hg, Pb and As of the method were 0.6, 1.5 and 0.8 ng x mL(-1) , respectively. Meanwhile, the analytical results of Hg, Pb and As in the Chinese national standard sediment reference samples were in good agreement with the certified values with the RSDs below 8%. Using the BCR and HG-ICP-AES technique, the content of each chemical species of Hg, Pb and As in soils of nonferrous metal mine area in western Hunan province was studied. The result showed that the Hg, Pb and As contents in soils were dominated by residual form, followed by organic and Fe-Mn oxides form, whereas acid-exchangeable form was rather low. The concentrations of the four Hg species in mine soil were 1.2, 3.0, 47 and 272 times higher than those in the control soil. While the concentrations of Pb and As in the same samples were 1.2, 4.6, 8.1 and 4.5 times and 1.5, 2.9, 3.3 and 2.2 times higher than those in the control soil, respectively. The results indicated that the soil in mine area in western Hunan province was co-polluted polluted by Hg, Pb and As.

[Determination of trace mercury and arsenic in human hair of polymetallic mining area by HG-ICP-AES]

In the present paper, a method for the determination of trace elements such as Hg and As in biological samples by HG-ICP-AES was presented. Under the optimum experimental conditions and instrumental operation parameters, both the RSDs of Hg and As with the method were below 3%, and the detection limits were 0.6 ng Hg x mL(-1) and 0.8 ng As x mL(-1), respectively, satisfying the demand of detecting trace Hg and As concentration in biological samples. Meanwhile, the analytical results of Hg and As in the national standard reference samples such as human hair (GBW 09101), rice (GBW 08503) and tea leaf (GBW 08505) were in good agreement with the certified values, with RSDs around 5%. Using the HG-ICP-AES method, the concentrations of Hg and As in human hair samples of polymetallic mining area in western Hunan province were determined, and the result shows that human in the mining area was exposed to high levels of Hg and As. The concentrations of Hg and As in the mining area were 1.290 and 1.865 microg x g(-1) respectively, 3.59 and 2.44 times higher than those in the control area, respectively.

[Chemical speciation and pollution characteristics of soil mercury in mercury deposit area of Western Hunan-Eastern Guizhou province]

By the BCR extraction procedures and HG-ICP-AES technique, the chemical speciation and pollution characteristics of soil mercury in typical mercury deposit areas of Western Hunan-Eastern Guizhou province were studied. It was found that the concentrations of mercury in soils are dominated by residual form, followed by organic-sulfide form. Fe-Mn oxides and acid-exchangeable form are rather low. The percent of the four mercury species in soils are 85.77%, 12.44%, 0.93% and 0:86%, respectively. The total concentrations and each species of mercury in soils show positive relationship with the concentration of sands, and negative relationship with the concentration of clays in soils. They also increase with the soil pH value. Mercury concentration in soils has spatial changes. In general, the concentrations in the surface soil are higher than those of sub-surface soils. Furthermore, the concentrations rapidly decrease with the distance from the pollution source increased and vary among different soil samples from different location and land use type. The results indicated that exogenous mercury pollution caused by human activities provides significant influence on environmental toxicity and pollution characteristics of mercury in soils of mercury deposit area.

[Study advance on haloacetic acids in drinking water]

Haloacetic acids (HAAs) in drinking water have attracted more and more attention of researchers due to their higher potential combination of chlorine, their carcinogenic and mutagenic effects and higher carcinogenic. The formation mechanism, analytical methods, the effects of many factors on HAAs formation such as precursor types, chlorine doses, pH, temperature, bromide, reaction time and seasonal change, toxicological character and the minimizing technology of HAAs in resent studies about HAAs are discussed in details in this paper. Further researches are still needed to clarify the formation mechanism of HAAs and find a feasible minimizing technology. New concerns including toxicological characters that correlate with human and other HAAs exposure routes besides oral ingestion (i.e., inhalation and dermal adsorption) should be put forward.

[Environmental quality of soil polluted by mercury and lead in polymetallic deposit areas of western Hunan Province]

The environmental quality of soil polluted by mercury and lead in typical polymetallic deposit areas of western Hunan province and its natural and human causes were studied. It was found that western Hunan province is a high regional geochemical abnormal region on mercury and lead. The concentrations of mercury and lead in soils in mercury deposit areas were 1 315 and 3.1 times higher than that of the average background of soils in China respectively, while those in soils in lead-zinc deposit areas were 14.8 and 16.1 times higher. Using geoaccumulation index developed by Muller, it was found that either mercury deposit area or lead-zinc deposit area in western Hunan province is polluted by the two elements, the majority soils in mercury deposit areas are seriously polluted by mercury with middle polluted or light polluted by lead, while the majority soils in lead-zinc deposit areas are middle polluted or middle-heavily polluted by lead and middle-heavily polluted by mercury. The sources of metal pollutants in soils in the deposit areas are natural and human causal, the spatial distribution of mercury and lead are dominated by original geochemical situation but seriously affected by human mining activities.

Contents of chemical elements in stomach during prenatal development: different age-dependent dynamical changes and their significance

AIM: To observe dynamic of different chemical elements in stomach tissue during fetal development.

METHODS: To determine contents of the 21 chemical elements in each stomach samples from fetus aging four to ten months. The content values were compared to those from adult tissue samples, and the values for each month group were also analyzed for dynamic changes.

RESULTS: Three representations were found regarding the relationship between contents of the elements and ages of the fetus, including the positive correlative (K), reversely correlative (Na, Ca, P, Al, Cu, Zn, Fe, Mn, Cr, Sr, Li, Cd, Ba, Se) and irrelevant groups (Mg, Co, Ni, V, Pb, Ti).

CONCLUSION: The chemical elements’ contents in stomach tissues were found to change dynamically with the stomach weights. The age-dependent representations for different chemical elements during the prenatal development may be of some significance for assessing development of fetal stomach and some chemical elements. The data may be helpful for the nutritional balance of fetus and mothers during prenatal development and even the perinatal stages.

A comprehensive system for protein purification and biochemical analysis based on antibodies to c-myc peptide

The genomics revolution has created a need for increased speed and generality for recombinant protein production systems as well as general methods for conducting biochemical assays with the purified protein products. 9E10 is a well-known high-affinity antibody that has found use in a wide variety of biochemical assays. Here we present a standardized system for purifying proteins with a simple epitope tag based on c-myc peptide using an antibody affinity column. Antibodies with binding parameters suitable for protein purification have been generated and characterized. To purify these antibodies from serum-containing medium without carrying through contaminating immunoglobulin G, a peptide-based purification process was developed. A fluorescence polarization binding assay was developed to characterize the antigen-antibody interaction. Protein purification protocols were optimized using a fluorescein-labeled peptide as a surrogate "protein." Binding and elution parameters were evaluated and optimized and basic operating conditions were defined. Several examples using this procedure for the purification of recombinant proteins are presented demonstrating the generality of the system. In all cases tested, highly pure final products are obtained in good yields. The combination of the antibodies described here and 9E10 allow for almost any biochemical application to be utilized with a single simple peptide tag.

[A study on thermal decomposition mechanism and quality analysis of pearl powder]

OBJECTIVE

To establish a rapid and convenient method for distinguishing genuine from sham of pearl powder as well as appraising its quality preliminarily.

METHOD

Thermogravimetry and differential thermogravimetry.

RESULT

The TG and DTG curves can be divided into two characteristic regions. The first step ranges from 250 to 380 degrees C with a weight loss of about 3%, resulting from the denaturalization and decomposition of organic matter in the powder; and the second step from 600 to 780 degrees C with a weight loss of about 40% resulting from the decomposition of calcium carbonate in the powder.

CONCLUSION

According to the two characteristic regions on TG and DTG curves along with corresponding parameters, pearl powder can be appropriately authenticated. Being related directly to the contents of organic matter in pearl powder, the first step is an important criterion for quality appraisal.

Microsatellite alterations on human chromosome 11 in in situ and invasive breast cancer: a microdissection microsatellite analysis and correlation with p53, ER (estrogen receptor), and PR (progesterone receptor) protein immunoreactivity

BACKGROUND AND OBJECTIVES

Microsatellite instability (MSI) has been documented in a subset of sporadic tumors. Loss of heterozygosity (LOH) on chromosome 11 loci in breast cancer is a frequent event. The purpose of the present study is to examine the incidence of microsatellite alterations in in situ and invasive human breast carcinoma and to clarify their significance in regulating the dynamics of cancer progression.

METHODS

Four highly polymorphic (CA)n repeat microsatellites were used to determine microsatellite alterations in ten ductal carcinoma in situ (DCIS) and 19 invasive ductal carcinoma (IDC). To investigate the expression of p53, ER (estrogen receptor), and PR (progesterone receptor) association with MSI, immunohistochemistry staining was applied.

RESULTS

MSI were detected in 20% (2/10) of DCIS and in 47.4% (9/19) of IDC. The frequency of MSI in IDC was significantly higher than that in DCIS (P < 0.001). Also, the MSI seemed to correlate with clinical stage (P = 0.0001) and tumor size (P = 0.004) but not histological grade or age. In addition, we found that 27% of the tumors showed LOH at 11q23.3-24 region between loci D11S934 and D11S912. Seven of nine MSI cases demonstrated low or no expression of p53. However, there was significantly reduced expression of PR, but not ER in MSI cases.

CONCLUSIONS

Our results suggest that breast cancer acquires the RER phenotype (replication-error phenotype) in the relatively late stages, and that the RER phenotype is associated with aggressiveness of IDC (infiltrative duct carcinoma). The result also implicated that mismatch repair failure can alter the expression of PR but not ER and p53.

Longitudinal analysis of methicillin-resistant Staphylococcus aureus isolates at a teaching hospital in Taiwan

In Taiwan, the frequency of nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has increased rapidly during the past 10 years. To investigate the epidemiology of MRSA infections, a total of 140 MRSA isolates collected at National Taiwan University Hospital from 1992 to 1996 were characterized by pulsed-field gel electrophoresis (PFGE) profiles and antibiotypes, as determined with the disk diffusion method. Among these isolates, six PFGE types (with 20 subtypes) and six antibiotypes were identified. Antibiotyping proved to be a poor method of epidemiologic analysis, because almost all of the MRSA isolates analyzed shared a very similar multidrug-resistant antibiotype. Most MRSA infections and colonizations in this hospital were due to the spread of strains belonging to three major PFGE types (A, B, and C). However, the major type changed in different years with types A, B, and C being predominant in 1992 through 1993, 1994 through 1995, and 1996, respectively. The three major PFGE types spread easily throughout the hospital wards, presumably carried by health care workers and environmental contamination. Our results demonstrate that there was a dominant strain spreading in our hospital each year and the dominant strain may shift in different years.

Ca2+ and Mg2+ selectively induce aggregates of PHF-tau but not normal human tau

The molecular mechanism of pathological aggregation of microtubule-associated protein tau during neurodegeneration is unclear. In the present study, the in vitro effect of various metal ions on the aggregation of tau was examined using paired helical filament tau (PHF-tau) obtained from corticobasal degeneration (CBD) and Alzheimer's disease (AD) brains as well as normal human tau proteins isolated from fetal and adult brains and a recombinant system. Among the metal ions tested, Ca2+ and Mg2+ effectively induced formation of approximately 340 kD aggregates of PHF-tau but not normal tau proteins as determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and immunoblotting. Al3+ and Fe2+ precipitated both PHF-tau and normal tau protein as SDS-insoluble pellets. The other metal ions examined (Cu2+, Zn2+, and Li+) were inactive and caused neither aggregation nor precipitation of any tau protein. Intermixing experiments using PHF-tau and various normal tau preparations showed that the 340-kD aggregates induced by Ca2+ contained PHF-tau but not normal tau regardless whether unmodified (recombinant) or highly phosphorylated (fetal brain) tau proteins were used. The present results suggest that post-translational modifications other than the fetal-type phosphorylation are required for Ca2+- and Mg2+-dependent aggregation of PHF-tau and that the regional elevation of these ions may trigger pathological deposition of PHF-tau in certain neurodegenerative disorders.

Hyaluronate binding assay study of transfected CD44 V4-V7 isoforms into the human gastric carcinoma cell line SC-M1

The potential human metastasis molecule CD44 and its isoforms V5 and V6 are overexpressed in human gastric carcinoma. Among the numerous extracellular matrix components, hyaluronate, a CD44 ligand, is of increasing interest in relation to its role in cancer cell development and invasion. By using the dynabead separation method, the SC-M1 cell line was separated into V5 and V6 isoform-positive and -negative populations. The V5 and V6 isoform-negative populations exhibited significantly higher hyaluronate binding activity than the corresponding positive cells. The hyaluronate binding activity of V5 and V6-positive cells could be restored by pretreatment with anti-CD44 V5 and V6 monoclonal antibodies (MAbs). In addition, transfection of aVV5 and V6-negative cells decreased their hyaluronate binding activity to the levels of CD44 V5 and V6-positive cells. Cells transfected with V5 and V6 recovered their hyaluronate binding activity after pretreatment with MAbs against V5 and V6. These data suggest that cell adhesion involving hyaluronate can be regulated by multiple mechanisms, one of which involves alternative splicing of CD44 isoforms.

Hyaluronate binding assay study of transfected CD44 V4-V7 isoforms into the human gastric carcinoma cell line SC-M1

The potential human metastasis molecule CD44 and its isoforms V5 and V6 are overexpressed in human gastric carcinoma. Among the numerous extracellular matrix components, hyaluronate, a CD44 ligand, is of increasing interest in relation to its role in cancer cell development and invasion. By using the dynabead separation method, the SC-M1 cell line was separated into V5 and V6 isoform-positive and -negative populations. The V5 and V6 isoform-negative populations exhibited significantly higher hyaluronate binding activity than the corresponding positive cells. The hyaluronate binding activity of V5 and V6-positive cells could be restored by pretreatment with anti-CD44 V5 and V6 monoclonal antibodies (MAbs). In addition, transfection of aVV5 and V6-negative cells decreased their hyaluronate binding activity to the levels of CD44 V5 and V6-positive cells. Cells transfected with V5 and V6 recovered their hyaluronate binding activity after pretreatment with MAbs against V5 and V6. These data suggest that cell adhesion involving hyaluronate can be regulated by multiple mechanisms, one of which involves alternative splicing of CD44 isoforms.

Tau released from paired helical filaments with formic acid or guanidine is susceptible to calpain-mediated proteolysis

Paired helical filaments (PHFs), a characteristic neuropathologic finding in Alzheimer's disease brain, are abnormal fibrillary forms of hyperphosphorylated tau (PHF-tau), which have been shown to be highly resistant to calpain digestion. Either excessive phosphorylation or fibrillary arrangement of tau proteins in PHFs may play a role in proteolytic resistance by limiting access to calpain recognition/digestion sites. To determine the contribution of the fibrillary conformation, isolated PHFs were subjected to treatment with either formic acid or guanidine. Both procedures effectively abolished the fibrillary structure of PHF but preserved PHF-tau immunoreactivity using a panel of antibodies that recognize nonphosphorylated and phosphorylated epitopes. These treatments also significantly increased the sensitivity of PHF-tau polypeptides to calpain proteolysis as shown by significant decreases in the half-life (t(1/2)) from the infinite with native PHF to 44 min and 4.4 min in formic acid- or guanidine-treated samples, respectively. In contrast, the sensitivity of normal fetal tau (3.4 min) was either decreased (5.9 min) or unaffected (3.6 min) by similar treatment. Our results indicate that after guanidine treatment, the sensitivity of PHF to calpain resembles that of fetal tau. These results strongly suggest that the fibrillary structure of PHF-tau, rather than hyperphosphorylation, is the major factor responsible for the resistance of abnormal filaments to calpain-mediated proteolysis.

Secular trends in the epidemiology of nosocomial fungal infections at a teaching hospital in Taiwan, 1981 to 1993

OBJECTIVE

To describe the incidence and patterns of nosocomial fungal infection in a large teaching hospital in Taiwan.

DESIGN

Prospective, hospitalwide nosocomial surveillance data from 1981 through 1993 were analyzed to show the secular trend in nosocomial fungal infection rates and to identify the most common pathogens and sites of infection (other than skin) in this hospital.

SETTING AND PATIENTS

The National Taiwan University Hospital is a medical school-affiliated hospital in the city of Taipei, Taiwan, with a 1200-bed capacity before 1991 and 1500 beds since 1992. It provides both primary and tertiary medical care.

RESULTS

The overall nosocomial fungal infection rate rose from 0.9 infections per 1000 discharges in 1981 to 6.6 per 1000 discharges in 1993, with the highest rate at the medical intensive-care unit (26.5/1000 discharges in 1993). This increase in infection rate was found at four major anatomic sites of infection, particularly including the bloodstream (0.08-2.19/1000 discharges) and the urinary tract (0.36-2.95/1000 discharges). Of 256 pathogens causing nosocomial fungemia from 1981 through 1993, Candida albicans was the most commonly isolated (50.8%), followed by Candida tropicalis (17.6%). Candida parapsilosis (11.7%), and Candida glabrata (8.2%). As compared to isolates from 1981 through 1988, the proportion of C parapsilosis and C glabrata isolated between 1989 and 1993 increased more than sixfold and fourfold, respectively. The increasing importance of fungal infections was confirmed further by the increased use of amphotericin B and azoles in this hospital.

CONCLUSIONS

Candida species and other yeasts have become a prominent cause of nosocomial infections in this hospital. These fungal pathogens accounted for a higher proportion of nosocomial bloodstream and urinary infections than any single bacterial species. Therefore, it is important to conduct a prospective epidemiological study and to establish in vitro antifungal susceptibility testing to enhance efforts to control nosocomial fungal infections and to minimize the risk of emergence of antifungal resistance.

Ultrastructural instability of paired helical filaments from corticobasal degeneration as examined by scanning transmission electron microscopy

Paired helical filaments (PHFs) accumulate in the brains of subjects affected with Alzheimer's disease (AD) and certain other neurodegenerative disorders, including corticobasal degeneration (CBD). Electron microscope studies have shown that PHFs from CBD differ from those of AD by being wider and having a longer periodicity of the helical twist. Moreover, PHFs from CBD have been shown to be primarily composed of two rather than three highly phosphorylated polypeptides of tau (PHF-tau), with these polypeptides expressing no exons 3 and 10. To further explore the relationship between the heterogeneity of PHF-tau and the appearance of abnormal filaments, the ultrastructure and physical parameters such as mass per unit length and dimensions were compared in filaments from CBD and AD using high resolution scanning transmission electron microscopy (STEM). Filament-enriched fractions were isolated as Sarcosyl-insoluble pellets and for STEM studies, samples were freeze-dried without prior fixation or staining. Ultrastructurally, PHFs from CBD were shown to be a heterogeneous population as double- and single-stranded filaments could be identified based on their width and physical mass per unit length expressed in kilodaltons (kd) per nanometer (nm). Less abundant, double-stranded filaments had a maximal width of 29 nm and a mass per unit length of 133 kd/nm, whereas three times more abundant single-stranded filaments were 15 nm wide and bad a mass per unit length of 62 kd/nm. Double-stranded filaments also displayed a distinct axial region of less dense mass, which appeared to divide the PHFs into two protofilament-like strands. Furthermore, these filaments were frequently observed to physically separate along the long axis into two single strands or to break longitudinally. In contrast, PHFs from AD were ultrastructurally stable and uniform both in their width (22 nm) and physical mass per unit length (104 kd/nm). The ultrastructural features indicate that filaments of CBD and AD differ both in stability and packing of tau and that CBD filaments, composed of two distinct protofilaments, are more labile under STEM conditions. As fixed and stained filaments from CBD have been shown to be stable and uniform in size by conventional transmission electron microscopy, STEM studies may be particularly suitable for detecting instability of unstained and unfixed filaments. The results also suggest that molecular heterogeneity and/or post-translational modifications of tau may strongly influence the morphology and stability of abnormal filaments.

Calpain-induced proteolysis of normal human tau and tau associated with paired helical filaments

The major components of neurofibrillary tangles (NFT) in Alzheimer's disease are bundles of paired helical filaments (PHF) which are primarily composed of highly phosphorylated tau proteins (PHF-tau). To further understand the mechanism of PHF accumulation in NFT, we examined the calpain-induced proteolysis of highly purified and primarily non-aggregated PHF and normal tau proteins with various contents of phosphate isolated from either fetal (F-tau) or adult human brain (N-tau). The extent of proteolysis was determined by decreases in tau immunoreactivity using Western-blot analysis and a panel of site-specific tau antibodies (Alz 50, Tau-2, Tau 14, Tau-1, AT8, E-11, AH-1 and PHF-1). We found that full-size polypeptides of N-tau and F-tau were similarly and rapidly proteolyzed in vitro by calpain (calpain II, 3.3 units/mg protein) during a 10-min incubation at 30 degrees C, and that their half lives (t1/2) were 1.5 min and 1.8 min, respectively. Analysis of immunoblots suggests that full-length polypeptides of tau are first degraded into large fragments similar in size to that generated endogenously, then into smaller fragments. Since both endogenous and in-vitro-generated tau fragments retained N-terminal epitopes, the results suggest that most of the calpain-sensitive sites may be located in the C-terminal half of the tau molecule. In contrast, PHF were extremely resistant to degradation and only a fivefold higher concentration of calpain (16.7 units/mg protein) induced partial proteolysis of PHF. A major calpain-generated fragment was a 45-kDa polypeptide derived from the C-terminal region of PHF-tau, which forms a core of filaments. The results suggest that the inaccessibility of potential calpain-digestion sites in the filament core could contribute to the resistance of PHF to calpain and subsequently lead to the accumulation of PHF in Alzheimer's disease. The results also suggest that hyperphosphorylation of tau may be marginally involved in the resistance of PHF to degradation by calpain. Ultrastructural examination revealed that, in contrast to previous studies with trypsin, calpain did not alter the morphologic appearance of filaments; after incubation with calpain, the majority of PHF remained short and disperse and the number of PHF aggregated into NFT-like clusters was not significantly increased. The results suggest that the role of calpain in promoting the aggregation and clustering of filaments is limited.