Rare MTNR1B variants impairing melatonin receptor 1B function contribute to type 2 diabetes

Genome-wide association studies have revealed that common noncoding variants in MTNR1B (encoding melatonin receptor 1B, also known as MT(2)) increase type 2 diabetes (T2D) risk(1,2). Although the strongest association signal was highly significant (P < 1 × 10(-20)), its contribution to T2D risk was modest (odds ratio (OR) of ～1.10-1.15)(1-3). We performed large-scale exon resequencing in 7,632 Europeans, including 2,186 individuals with T2D, and identified 40 nonsynonymous variants, including 36 very rare variants (minor allele frequency (MAF) <0.1%), associated with T2D (OR = 3.31, 95% confidence interval (CI) = 1.78-6.18; P = 1.64 × 10(-4)). A four-tiered functional investigation of all 40 mutants revealed that 14 were non-functional and rare (MAF < 1%), and 4 were very rare with complete loss of melatonin binding and signaling capabilities. Among the very rare variants, the partial- or total-loss-of-function variants but not the neutral ones contributed to T2D (OR = 5.67, CI = 2.17-14.82; P = 4.09 × 10(-4)). Genotyping the four complete loss-of-function variants in 11,854 additional individuals revealed their association with T2D risk (8,153 individuals with T2D and 10,100 controls; OR = 3.88, CI = 1.49-10.07; P = 5.37 × 10(-3)). This study establishes a firm functional link between MTNR1B and T2D risk.     

Meta-analysis identifies common variants associated with body mass index in east Asians

Multiple genetic loci associated with obesity or body mass index (BMI) have been identified through genome-wide association studies conducted predominantly in populations of European ancestry. We performed a meta-analysis of associations between BMI and approximately 2.4 million SNPs in 27,715 east Asians, which was followed by in silico and de novo replication studies in 37,691 and 17,642 additional east Asians, respectively. We identified ten BMI-associated loci at genome-wide significance (P < 5.0 × 10(-8)), including seven previously identified loci (FTO, SEC16B, MC4R, GIPR-QPCTL, ADCY3-DNAJC27, BDNF and MAP2K5) and three novel loci in or near the CDKAL1, PCSK1 and GP2 genes. Three additional loci nearly reached the genome-wide significance threshold, including two previously identified loci in the GNPDA2 and TFAP2B genes and a newly identified signal near PAX6, all of which were associated with BMI with P < 5.0 × 10(-7). Findings from this study may shed light on new pathways involved in obesity and demonstrate the value of conducting genetic studies in non-European populations.     

Germline deletion of the miR-17∼92 cluster causes skeletal and growth defects in humans

MicroRNAs (miRNAs) are key regulators of gene expression in animals and plants. Studies in a variety of model organisms show that miRNAs modulate developmental processes. To our knowledge, the only hereditary condition known to be caused by a miRNA is a form of adult-onset non-syndromic deafness, and no miRNA mutation has yet been found to be responsible for any developmental defect in humans. Here we report the identification of germline hemizygous deletions of MIR17HG, encoding the miR-17～92 polycistronic miRNA cluster, in individuals with microcephaly, short stature and digital abnormalities. We demonstrate that haploinsufficiency of miR-17～92 is responsible for these developmental abnormalities by showing that mice harboring targeted deletion of the miR-17～92 cluster phenocopy several key features of the affected humans. These findings identify a regulatory function for miR-17～92 in growth and skeletal development and represent the first example of an miRNA gene responsible for a syndromic developmental defect in humans.     

A mutation of human cytochrome c enhances the intrinsic apoptotic pathway but causes only thrombocytopenia

We report the first identified mutation in the gene encoding human cytochrome c (CYCS). Glycine 41, invariant throughout eukaryotes, is substituted by serine in a family with autosomal dominant thrombocytopenia caused by dysregulated platelet formation. The mutation yields a cytochrome c variant with enhanced apoptotic activity in vitro. Notably, the family has no other phenotypic indication of abnormal apoptosis, implying that cytochrome c activity is not a critical regulator of most physiological apoptosis.     

电解还原法制L-半胱氨酸盐酸盐电解工艺条件的研究

本文用自制板框式电解槽对电解还原制备L-半胱氨酸盐酸盐的工艺条件,如电解终止时间的判断、电极、电解质溶液、隔膜……等进行了一系列的选择和研究。特别是采用电解液外循环工艺,研究了循环流速对电解还原速度的影响,以及流速和电流密度等诸因素的关系。     

杯芳烃的配位化学(Ⅺ)——4种杯[4]芳烃萃取铁(Ⅲ)的研究

合成了杯［４］ 芳烃、四对叔丁基杯［４］ 芳烃、四乙氧基羰基甲氧基四对叔丁基杯［４］ 芳烃、四乙酰基甲氧基四对叔丁基杯［４］ 芳烃等４ 种杯芳烃,研究了这些杯芳烃对铁（ Ⅲ） 的萃取化学,讨论了这些体系的萃取机理,并求出了它们的萃取平衡常数     

腎钙乳沉积症(附1例报告及文献复习)

本文报告1例罕见的肾钙乳沉积症,本症是肾盂源性囊肿内有钙乳沉积,分为两类;第一类,钙乳沉积于扩大的肾盂源性囊肿内,肾功能正常,占多数;第二类,有明显的肾积水和肾盏扩张,合并多发性钙乳沉积,肾功能差,属少数。病理检查,肾囊肿囊壁有肾单位存在,估计是由于集合管梗阻而形成的囊肿,经年累月接受其所属肾单位分泌的微量尿液,在浓缩功能差的情况下,潴留囊肿内的晶体便保持糊状微粒状态。本例钙乳沉积物的化学分析表明,其成份含有9种元素,其中以钙、铝、硅、及镁含量最多。x线检查的特征性图像是诊断本症的主要方法。囊肿去盖术对本症是一种安全而有效的术式。