Roxarsone transformation and its impacts on soil enzyme activity in paddy soils: A new insight into water flooding effects.

The aromatic arsenical roxarsone (ROX) has been used as feed additive for decades worldwide. The past or present application of animal manure containing ROX in paddy fields results in arsenic (As) accumulation in rice grain. However, the degradation and transformation mechanisms of ROX in paddy soil which determine As bioavailability and uptake by rice are still unclear. The current study investigated the variation of As speciation and soil enzyme activities in ROX-treated soils under flooded and non-flooded conditions for six months. Our results showed that 70.2% of ROX persisted in non-flooded paddy soils after 180 d while ROX degraded completely within 7 d in flooded soils. The rapid degradation of ROX under flooded conditions owed to the enhanced biotic transformation that was caused by the low Eh and the predominant presence of Clostridium spp. and Bacillus spp. ROX was not only transformed to As(III) and As(V) in non-flooded soils but also to 3-amino-4-hydroxyphenylarsonic acid and methyl arsenicals in flooded soils. The degradation products significantly inhibited soil enzyme activities for 7-30 d, but the inhibition effects disappeared after 90 d due to the sorption of transformed As products to amorphous Fe oxides. This study provides new insights into the flooding effect on ROX fate in paddy fields, which is important for the management of animal waste and risk control on polluted sites.

Longitudinal study of childhood adiposity and the risk of developing components of metabolic syndrome-the Da Qing children cohort study.

Childhood adiposity is increasingly recognized as a significant predictor of cardiometabolic risks in later life. The aim of this study was to investigate factors associated with longitudinal changes in weight during childhood and the development of metabolic disease risk factors. Four hundred twenty-four children from DaQing city, China, were recruited at 5 y old and followed up for 5 y. Birth weight, television (TV) viewing time at 5 y old, blood pressure, anthropometric measurements, fasting plasma insulin (FI), and triglycerides (TG) levels were measured at 5 and 10 y old. Both birth weight and TV viewing time at 5 y old significantly correlated with percentage of ideal weight for height (WFH) at 5 y old (WFH5; p = 0.0032 and p = 0.01), but only TV time was significantly correlated with WFH at 10 y old (WFH10; p < 0.0001). Blood pressures, FI, homeostasis model assessment for insulin resistance (HOMA-IR), and TG at 10 y old were significantly greater in those children who had greater change in WFH from 5 to 10 y old (ΔWFH). We concluded that TV viewing time was the stronger determinant of later childhood adiposity. A greater ΔWFH was associated with increased cardiometabolic risk factors at 10 y old.

[Features of insulin secretion and insulin resistance in newly diagnosed type 2 diabetes of different body mass indices].

OBJECTIVE: To investigate insulin secretion function and insulin resistance in Chinese newly diagnosed type 2 diabetes (obese and non-obese patients) in order to provide evidence for clinical treatment. METHODS: 408 newly diagnosed type 2 diabetes and 40 normal controls were recruited. Height, weight were measured, insulin and glucose of 0 min, 30 min, 60 min, 120 min during oral glucose tolerance test were examined. The patients with fasting glucose level greater than 8.3mmol/L were treatment with Gliclazide for 1 - 3 months. After normalization of the plasma glucose levels for more than 2 weeks, and withdraw this medication for 48 hours, then OGTT were repeated to assess IR and IS. RESULTS: The patients were divided into four groups based on fasting plasma glucose (DM1: FPG < 6.9mmol/L; DM2: 6.9 mmol/L < or = FPG < 8.3 mmol/L; DM3: 8.3 mmol/L < or = FPG < 9.7 mmol/L; DM4: FPG > or = 9.7 mmol/L). Every groups were further stratified to subgroups by cut point of BMI = 24 kg/m(2). Their insulin sensitivity and insulin secretion function compared between subgroups. (1) True insulin level in BMI > or = 24 (FPG < 6.9 mmol/L) subgroups were higher than control's (3.5 +/- 0.5 vs 3.2 +/- 0.6 natural logarithm) (P < 0.05). (2) In BMI > or = 24 subgroups, their insulin sensitivity were even worse than BMI < 24 groups', but their insulin secretion function were better at the same FPG level. (3) After intervention, the change of insulin sensitivity in BMI < 24 group was better than BMI > or = 24 group's (-4.7 +/- 0.9 vs -5.5 +/- 1.4 natural logarithm) (P < 0.05); but the change of insulin secretion function in BMI < 24 group was worse. CONCLUSION: (1) In newly diagnostic type 2 diabetes, insulin sensitivity and insulin secretion function were decreased with the increase of FPG, but they were different between obese and non-obese group. (2) Insulin secretion function was recovered better in obese group when eliminated glucose toxicity.

[Study on the distribution and risk factors of hypertension among children: a cohort study].

OBJECTIVE: To explore the association between hypertension and the tendency of change among children,so as to lay a foundation for the prevention and control of hypertension. METHODS: Based on findings from the prevalence survey that carried out in September 1999 in Daqing of Heilongjiang province. New admission children were selected as subjects to conduct a five-year cohort study. All the subjects were interviewed with questionnaires and their blood specimens were collected for biochemical analysis. All data were analyzed using SPSS 10.0 software. Results The prevalence of hypertension among 447 children was found 2.01% at the baseline study but increased to 5.37% in the fifth year. During a five year period, the systolic pressure level among children increased from (100.65 +/- 11.62)mmHg (1 mm Hg = 0.133 kPa) to (106.67 +/- 9.29) mm Hg,while the diastolic pressure level was from (66.27 +/- 11.31) mm Hg to (70.28 +/- 7.98) mm Hg and showed significant difference between boys and girls. There were association between hypertension and family history, body mass index (BMI), triglyceride, insulin, insulin resistance index while insulin sensitivity index and family history, BMI and insulin sensitivity index appeared to be the important factors. Children under this study were divided to 'with family history or without' and then every group was divided to 'with over weight-obesity or normal'. Obesity and insulin sensitivity seemed the key risk factors on hypertension. Descent of insulin sensitivity was an independent risk factor. CONCLUSION: The level of blood tension among children in Daqing city was higher than that from the national data. The present study confirmed that over-weight,obesity, heredity and insulin resistance were the risk factors of hypertension while insulin resistance was related to hypertension. The interaction of these risk factors was independent or correlated to each other.