Pancreatic A cell function was studied in 119 cases of NIDDM with 37 normal subjects as controls. In NIDDM group, fasting plasma glucagon leveh averaged 192.9 ? 129.6 pg /ml, whereas in normals being 132.8?65.0 pg / ml. Plasma glucagon levels were markedly elevated in patients with NIDDM irrespective of insulin administration, suggesting decreased pancreatic A cell sensitivity to glucose.In 7 male normal subjects, following intravenous injection of insulin (0.1 U / kg) an average increment of 114 pg / ml of plasma glucagon level with a peak at 30-60 min was noted. In 3 of 6 male diabetic subjects a paradoxical reduced plasma glucagon response to insulin-induced hypoglycemia was demonstrated, suggesting primary abnormality of pancreatic A cell function in NIDDM patients, with a possible defect in glucose counter-regulation.

Objective To study the expressions of matrix metalloproteinase (MMP) gene family in papillary thyroid carcinoma (PTC) and its relationship to the pathogenesis of PTC. Methods The thyroid tissues of patients were collected in surgical operation, including 8 cases with papillary thyroid carcinoma, 7 cases with Hashimoto′s thyroiditis, 8 cases with adenoma and 8 normal tissues. The total RNA of these samples were extracted and purified by the method of acidic phenol. The gene expressions of MMP-2, MMP-9, MMP-14, MMP-25 and MMP-26 were assayed by RT-PCR and 1% agarose gel electrophoresis. The fluorescent degree of electrophoretic bands was detected by automatic gel scanner and analyzed statistically in order to compare the levels of gene expressions among 4 groups. Results The positive rates and the levels of MMP-2, MMP-9 and MMP-14 gene expressions in PTC group were significantly higher than those in other 3 groups (all P

Objective: To explore the association between DNA methylation and body mass index (BMI) using Mendelian randomization analysis. Methods: A total of 469 participants were selected from the Chinese National Twin Registry in 2013, who were living in Shandong, Jiangsu, Zhejiang, and Sichuan provinces, and at least 18 years of age. A questionnaire survey and physical examination were conducted to collect demographic, clinical, and behavioral information. Peripheral blood cells were collected to detect genotype and methylation status. Association analyses between DNA methylation and BMI and between CpGs and cis-SNP were conducted. With rs748212 as the instrumental variable, the association between cg15053022 and BMI was explored using the Mendelian randomization method. Results: A total of 469 participants were selected. The mean age of participants was (44.8±13.2) years and the BMI was (25.0±3.8) kg/m². Nine BMI-related DNA methylation sites were found and DNA methylation site cg15053022 in the ATP4A gene was negatively associated with cis-SNP rs748212 (β=-0.020); the mean methylation level of AA, AC, and CC were 0.212±0.025, 0.242±0.024, and 0.264±0.028, respectively. rs748212 was associated with BMI (β=0.04, P=0.007) and closely related to cg15053022 (F=237.66, P=0.143). Mendelian randomization analysis showed lower methylation levels at cg15053022 were associated with higher BMI (β=-1.97, P<0.001). Conclusion This study supported the impact of cg15053022 methylation in the ATP4A gene on BMI using Mendelian randomization analysis and provided the basis for using Mendelian randomization analysis in methylation studies.

OBJECTIVETo understand the change trend of birth weight of twins in China from 1995 to 2012.

METHODSA total of 10 827 twins born between 1995 and 2012 registered in national twin registry system in 8 provinces in China were included in this study. A retrospective study was conducted to analyze the change trend of twin's birth weight.

RESULTSMean birth weight of twins decreased by 0.01 kg every five years after adjusting sex, ovum type and place of birth (P = 0.041). The birth weight decreased both in superior twin and in inferior twin over time. After 2007, the birth weight of superior twin decreased by 0.008 kg each year, while the birth weight of inferior twin decreased by 0.014 kg each year. Mean relative difference in birth weight and birth weight discordant rate decreased before 2002, then increased from the lowest point 8.16% and 16.20% to highest point 9.99% and 22.40% respectively.

CONCLUSIONThe birth weight of twins in China decreased between 1995 and 2012, while the birth weight discordant rate increased, suggesting that close attention should be paid to the discordance of twin body weight to reduce the risk of adverse health outcome.

Birth Rate ; Birth Weight ; China ; epidemiology ; Humans ; Infant, Newborn ; Registries ; Retrospective Studies ; Twins

OBJECTIVETo explore the heritability of body mass index (BMI) in twins across different regions and genders in China.

METHODSA total of 11 122 adult twin pairs from the Chinese National Twin Registry were interviewed. A structural equation model was used to estimate the heritability of BMI.

RESULTSThis study included 6 226 monozygotic twin pairs and 4 896 dizygotic twin pairs, with the age range as 25-85 (39.0 ± 10.8) years. Under stratified analysis by region, results showed that the highest and lowest rates on heritability of BMI in men were seen in Tianjin and Zhejiang, as 67.8% (95% CI: 50.1%-85.8%) and 42.1% (95% CI: 27.2%-60.9%), while in women were seen in Sichuan and Heilongjiang as 56.2% (95% CI: 47.5%-70.0%) and 11.2% (95% CI: 0.0%-31.7%), respectively. Results from the stratified analysis showed that, by gender, the heritability of BMI in men was higher than that in women from the same region. The biggest differences of heritability of BMI between men and women were seen in Heilongjiang as 55.3% (95% CI: 35.5%-80.0%) and 11.2% (95% CI: 0-31.7%), while the smallest differences were seen in Sichuan as 61.5% (95% CI: 40.7%-86.4%) and 56.2% (95% CI: 47.5%-70.0%), respectively.

CONCLUSIONThe heritability of BMI across different regions and genders showed certain differences in the Chinese twins.

Adult ; Aged ; Aged, 80 and over ; Asian Continental Ancestry Group ; genetics ; Body Mass Index ; China ; Cities ; Female ; Humans ; Male ; Middle Aged ; Registries ; Twins, Dizygotic ; genetics ; statistics & numerical data ; Twins, Monozygotic ; genetics ; statistics & numerical data

OBJECTIVETo analyze the associations between birth weight and overweight/obesity among children.

METHODSA total of 8 267 twin pairs younger than 18 years old from the Chinese National Twin Registry were included in the study. Associations between birth weight, childhood BMI and overweight/obesity were explored by this co-twin control study.

RESULTSAfter adjusting for sex and zygosity, when birth weight had an increase of 0.5 kg per fold, the OR values for overweight and obesity were 1.87(95%CI: 1.40-2.48) for 2-6 year olds, 1.69 (95%CI: 1.16-2.46) for 6-12 year olds and 1.28 (95%CI: 0.80-2.07) for 12-18 year olds.

RESULTSfrom the stratified analysis in the 2-6 year-olds, statistically significant differences were seen. When birth weight increased 0.5 kg per fold, the risk of overweight and obesity increased by 0.87 times among the dizygotic twins, more than that of the monozygotic twins (OR=1.86, 95%CI:1.24-2.81). The risk for male twins was 1.12 times higher than that of female twins (OR=1.65, 95%CI:1.11-2.44).

CONCLUSIONSBirth weight seemed associated with overweight and obesity for kids at early childhood or at age for schools. However, guidance on the implementation of public health interventions is still needed on these children.

Adolescent ; Birth Weight ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Male ; Obesity ; ethnology ; Overweight ; ethnology ; Registries ; Risk ; Twins, Dizygotic ; Twins, Monozygotic

Objective: To analyze the heritability of diabetes among the Chinese twin adults. Methods: A total of 10 253 same-sex twin pairs aged 25 years and older, were selected from the Chinese National Twin Registry (CNTR) program. Heritability of diabetes was calculated by using the structural equation model. Results: After adjusted for age and gender, the overall heritability rates of diabetes were 0.41 (0.15-0.75), 0.83 (0.72-0.91) and 0.34 (0.04-0.73) in the <45 and ≥45 years twin pairs, respectively. After adjusted for age, rates of heritability appeared as 0.37 (0.05-0.78) and 0.88 (0.79-0.94) in men and women, respectively. Conclusions Diabetes is affected by both genetic and environmental factors. The genetic effect of diabetes seemed stronger on female than that on male twins but was dying down along with ageing.