44 research outputs found

    Glucose lowering effect of transgenic human insulin-like growth factor-I from rice: in vitro and in vivo studies

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    <p>Abstract</p> <p>Background</p> <p>Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains.</p> <p>Results</p> <p>The plant-codon-optimized hIGF-I was introduced into rice via <it>Agrobacterium</it>-mediated transformation. To enhance the stability and yield of rhIGF-I, the endoplasmic reticulum-retention signal and glutelin signal peptide were used to deliver rhIGF-I to endoplasmic reticulum for stable accumulation. We found that only glutelin signal peptide could lead to successful expression of hIGF-I and one gram of hIGF-I rice grain possessed the maximum activity level equivalent to 3.2 micro molar of commercial rhIGF-I. <it>In vitro </it>functional analysis showed that the rice-derived rhIGF-I was effective in inducing membrane ruffling and glucose uptake on rat skeletal muscle cells. Oral meal test with rice-containing rhIGF-I acutely reduced blood glucose levels in streptozotocin-induced and Zucker diabetic rats, whereas it had no effect in normal rats.</p> <p>Conclusion</p> <p>Our findings provided an alternative expression system to produce large quantities of biologically active rhIGF-I. The provision of large quantity of recombinant proteins will promote further research on the therapeutic potential of rhIGF-I.</p

    Hong Kong Chinese school children with elevated urine melamine levels: A prospective follow up study

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    <p>Abstract</p> <p>Background</p> <p>In 2008, the outbreak of kidney stones in children fed by melamine-tainted milk products in Mainland China has caused major public concern of food safety. We identified Hong Kong school children with elevated urine melamine level from a community-based school survey in 2007-08 and reviewed their clinical status in 2009.</p> <p>Methods</p> <p>In 2007-08, 2119 school children participated in a primary and secondary school survey in Hong Kong using a cluster sampling method. Urine aliquots from 502 subjects were assayed for melamine level. High urine melamine level was defined as urine melamine/creatinine ratio >7.1 μg/mmol. Subjects with high urine melamine level were invited for clinical evaluation in 2009 including urinalysis and ultrasound imaging of the urinary system.</p> <p>Results</p> <p>The age range of this subcohort was 6 - 20 years with 67% girls (335 female and 167 male subjects). The spot urine melamine/creatinine ratio of the 502 urine aliquots ranged from undetectable to 1467 μg/mmol (median 0.8 μg/mmol). Of these, 213 subjects had undetectable level (42%). We invited 47 (9%) subjects with high urine melamine level for re-evaluation and one subject declined. The median duration of follow-up was 23.5 months (interquartile range: 19.8 - 30.6 months). None of the 46 subjects (28% boys, mean age 13.9 ± 2.9 years) had any abnormality detected on ultrasound study of the urinary system. All subjects had stable renal function with a median urine albumin-creatinine ratio of 0.70 mg/mmol (interquartile range: 0.00 - 2.55 mg/mmol).</p> <p>Conclusions</p> <p>Hong Kong Chinese school children with high urine melamine levels appeared to have benign clinical course in the short term although a long term follow-up study is advisable in those with persistently high urine melamine level.</p

    Lipid control and use of lipid-regulating drugs for prevention of cardiovascular events in Chinese type 2 diabetic patients: a prospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Dyslipidaemia is an important but modifiable risk factor of cardiovascular disease (CVD) in type 2 diabetes. Yet, the effectiveness of lipid regulating drugs in Asians is lacking. We examined the effects of lipid control and treatment with lipid regulating drugs on new onset of CVD in Chinese type 2 diabetic patients.</p> <p>Methods</p> <p>In this prospective cohort consisting of 4521 type 2 diabetic patients without history of CVD and naïve for lipid regulating treatment recruited consecutively from 1996 to 2005, 371 developed CVD after a median follow-up of 4.9 years. We used Cox proportional hazard regression to obtain the hazard ratios (HR) of lipids and use of lipid regulating drugs for risk of CVD.</p> <p>Results</p> <p>The multivariate-adjusted HR (95% confidence interval) of CVD in patients with high LDL-cholesterol (≥ 3.0 mmol/L) was 1.36 (1.08 - 1.71), compared with lower values. Using the whole range value of HDL-cholesterol, the risk of CVD was reduced by 41% with every 1 mmol/L increase in HDL-cholesterol. Plasma triglyceride did not predict CVD. Statins use was associated with lower CVD risk [HR = 0.66 (0.50 - 0.88)]. In sub-cohort analysis, statins use was associated with a HR of 0.60 (0.44 - 0.82) in patients with high LDL-cholesterol (≥ 3.0 mmol/L) and 0.49 (0.28 - 0.88) in patients with low HDL-cholesterol. In patients with LDL-cholesterol < 3.0 mmol/L, use of fibrate was associated with HR of 0.34 (0.12 - 1.00). Only statins were effective in reducing incident CVD in patients with metabolic syndrome [(HR = 0.58(0.42--0.80)].</p> <p>Conclusions</p> <p>In Chinese type 2 diabetic patients, high LDL-cholesterol and low HDL-cholesterol predicted incident CVD. Overall, patients treated with statins had 40-50% risk reduction in CVD compared to non-users.</p

    Social Europe. No 2/87

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    BACKGROUND: DNA methylation is an important type of epigenetic modification involved in gene regulation. Although strong DNA methylation at promoters is widely recognized to be associated with transcriptional repression, many aspects of DNA methylation remain not fully understood, including the quantitative relationships between DNA methylation and expression levels, and the individual roles of promoter and gene body methylation. RESULTS: Here we present an integrated analysis of whole-genome bisulfite sequencing and RNA sequencing data from human samples and cell lines. We find that while promoter methylation inversely correlates with gene expression as generally observed, the repressive effect is clear only on genes with a very high DNA methylation level. By means of statistical modeling, we find that DNA methylation is indicative of the expression class of a gene in general, but gene body methylation is a better indicator than promoter methylation. These findings are general in that a model constructed from a sample or cell line could accurately fit the unseen data from another. We further find that promoter and gene body methylation have minimal redundancy, and either one is sufficient to signify low expression. Finally, we obtain increased modeling power by integrating histone modification data with the DNA methylation data, showing that neither type of information fully subsumes the other. CONCLUSION: Our results suggest that DNA methylation outside promoters also plays critical roles in gene regulation. Future studies on gene regulatory mechanisms and disease-associated differential methylation should pay more attention to DNA methylation at gene bodies and other non-promoter regions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13059-014-0408-0) contains supplementary material, which is available to authorized users

    The problem of obesity among adolescents in Hong Kong: a comparison using various diagnostic criteria

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    <p>Abstract</p> <p>Background</p> <p>Obesity is now a global epidemic. In this study, we aimed to assess the rates of obesity using several major diagnostic criteria in Chinese school adolescents in Hong Kong.</p> <p>Methods</p> <p>This is a cross-sectional study. Using a computer-generated coding system, we randomly selected schools from different geographical regions in Hong Kong to obtain a representative sample. Subjects aged 11–18 years of age were randomly selected from different class of the schools. Their rates of obesity according to four different international and local criteria were compared [International Obesity Task Force (IOTF) 2000 criterion; the Group of China Obesity Task Force (COTF) 2004 criterion; Centers for Disease Control and Prevention (CDC) 2000 Growth Charts and the Hong Kong Growth Survey (HKGS) charts in 1993].</p> <p>Results</p> <p>Of the 2098 adolescents [982 (46.8%) boys and 1116 (53.2%) girls], the mean age (± SD) was 15.1 ± 1.8 years (range: 11–18 years; median: 15.0 years). The crude rates of obesity were similar based on IOTF, COTF or CDC criteria (boys: 3.9–6.0%, girls: 1.8–3.7%), however, the rate increased to 11–27% if the HKGS charts were used. Obesity rate varied markedly according to age. It decreased from 8–10% among those aged 12–13 years to 2–4% among those aged 17–18 years.</p> <p>Conclusion</p> <p>The prevalence of obesity in Hong Kong adolescents using various diagnostic criteria were similar except for the 1993 HKGS criteria, which gave an exceeding high figure. Using the IOTF, COTF or CDC criteria, the adolescent obesity in Hong Kong varied from 1.8% to 6.0%.</p

    Association between Physical Activity and Cardiovascular Risk in Chinese Youth Independent of Age and Pubertal Stage

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    <p>Abstract</p> <p>Background</p> <p>Childhood and adolescence are critical periods of habit formation with substantial tracking of lifestyle and cardiovascular risk into adulthood. There are various guidelines on recommended levels of physical activity in youth of school-age. Despite the epidemic of obesity and diabetes in China, there is a paucity of data in this regard in Chinese youth. We examined the association of self-reported level of physical activity and cardiovascular risk in Hong Kong Chinese youth of school-age.</p> <p>Methods</p> <p>This was a cross-sectional study conducted in 2007-8 in a school setting with 2119 Hong Kong Chinese youth aged 6-20 years. Physical activity level was assessed using a validated questionnaire, CUHK-PARCY (The Chinese University of Hong Kong: Physical Activity Rating for Children and Youth). A summary risk score comprising of waist circumference, blood pressure, fasting plasma glucose and lipids was constructed to quantify cardiovascular risk.</p> <p>Results</p> <p>In this cohort, 21.5% reported high level of physical activity with boys being more active than girls (32.1% versus 14.1%, p < 0.001). Regression analysis showed physical activity level, sex and pubertal stage were independently associated with cardiovascular risk score.</p> <p>Conclusion</p> <p>Self-reported level of physical activity is associated with cardiovascular risk factors in Chinese youth after adjusting for sex and pubertal stage.</p
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