异落新妇甙的结构研究

从百合科菝葵属植物土茯苓(Smilaxg labra Roxb.)根茎的乙醇提取物中分得一个新的天然化合物(I),命名为异落新妇甙(isoastilbin)。根据元素分析,UV,IR,¹H-NMR,¹³C-NMR,2DNMR及FAB-MS,确定化合物I的结构为5,7,3',5'-四羟基二氢黄酮醇-3-O-α-L-鼠李糖甙。     

C2H2-171 : A novel human cDNA representing a developmentally regulated poz domain/zinc finger protein preferentially expressed in brain

We describe a novel human zinc finger cNDA, C2H2-171. This cDNA represents an mRNA which encodes a protein of 484 amino acids and a calculated molecular weight of 54 kD. Four zinc finger-like domains are found in the C-terminal end of the protein. At the N-terminus, C2H2-171 contains a POZ/tramtrack-like domain similar to that found in the tumor associated zinc finger proteins LAZ-3/BCL-6 and PLZ-F, as well as in non-zinc finger proteins. C2H2-171 RNA is preferentially expressed in the brain, and increases during the course of murine development, with maximal expression in the adult. C2H2-171 RNA is differentially expressed in brain regions, with the highest level of expression in the cerebellum. C2H2-171 RNA was expressed at high levels in primary cerebellar granule cell neurons compared to astrocytes. The gene encoding C2H2-171 is highly conserved in vertebrates, and maps to the terminus of human chromosome 1 (1q44-ter). This chromosomal location is associated with a number of cytogenetic aberrations including those involving brain developmental anomalies and tumorigenesis. These data suggest that C2H2-171 may play an important role in vertebrate brain development and function.     

Serum levels of growth hormone-binding protein and insulin-like growth factor-I during puberty.

OBJECTIVE: The aim was to investigate the effect of pubertal development on serum levels of growth hormone binding protein (GHBP) and IGF-I, and to study the relationship between GHBP levels and height standard deviation score (SDS), nutritional state and IGF-I levels. DESIGN AND PATIENTS: The investigation was performed on serum samples from 72 healthy adolescents of different pubertal stage. Results were compared to those obtained in 46 prepubertal children. MEASUREMENTS: Serum levels of GHBP were measured by HPLC gel filtration and IGF-I levels were measured by RIA after acid-ethanol extraction. RESULTS: No effect of pubertal stage on serum levels of GHBP was found. A positive relationship was found between serum levels of GHBP and height SDS (r = 0.38; P < 0.005) and weight expressed as percentage of median weight for height age (r = 0.46; P < 0.0005). Serum levels of IGF-I increased during puberty and were not correlated with height SDS or weight for height age. In pubertal subjects, no relationship existed between serum levels of GHBP and IGF-I. In prepubertal subjects, however, a significantly positive relationship between GHBP and IGF-I levels (r = 0.66; P < 0.0005) was found. CONCLUSIONS: Pubertal development does not seem to influence serum levels of GHBP. Height SDS and nutritional state are related to the concentration of GHBP. Before puberty, the level of GHBP is positively related to IGF-I levels; during puberty, however, the increase in serum IGF-I levels is not accompanied by changes in the amount of circulating GHBP.     

Torsional properties of the Canal Master instrument.

The torsional properties of a new type of endodontic hand instrument, the Canal Master, were compared with conventional machined K-type endodontic files. Sizes 20 through 50 were tested in clockwise (CW) and counterclockwise (CCW) directions. Canal Master instruments exhibited significantly less torque at yield and at failure in both the CW and CCW directions. Rotation at failure was significantly greater for the Canal Master instruments in both CW and CCW directions. There was no significant difference in either torque or the amount of rotation for the Canal Master instruments when comparing CW versus CCW rotation. There was no clinically visible evidence of deformation of the Canal Master instruments prior to torsional failure.     

一些保肝药物对原代培养大鼠肝细胞糖原合成功能的影响

本文参照PO Seglen的方法并加以修改,建立了原代培养大鼠肝细胞糖原合成功能的测定体系。观察到联苯双酯既能使正常肝细胞合成糖原增加88%,又能保护肝细胞完全拮抗四氯化碳对其功能的损伤;银耳多糖能使四氯化碳对肝细胞糖原合成功能的损伤减轻57%;去甲斑蝥素10μg/ml能增加肝细胞糖原合成,浓度增加到100μg/ml时,此作用减弱,1000μg/ml则明显抑制糖原的合成,而且在10～100μg/ml浓度时,即能加强四氯化碳的损伤作用;100μg/ml CL₁₅₀₀和熊果酸二钠单独应用可增加肝细胞糖原合成,但与四氯化碳同时应用,反而加重对糖原合成的抑制作用。     

KCNJ11 activating mutations in Italian patients with permanent neonatal diabetes

Permanent neonatal diabetes mellitus (PNDM) is a rare condition characterized by severe hyperglycemia constantly requiring insulin treatment from its onset. Complete deficiency of glucokinase (GCK) can cause PNDM; however, the genetic etiology is unknown in most PNDM patients. Recently, heterozygous activating mutations of KCNJ11, encoding Kir6.2, the pore forming subunit of the ATP-dependent potassium (K(ATP)) channel of the pancreatic beta-cell, were found in patients with PNDM. Closure of the K(ATP) channel exerts a pivotal role in insulin secretion by modifying the resting membrane potential that leads to insulin exocytosis. We screened the KCNJ11 gene in 12 Italian patients with PNDM (onset within 3 months from birth) and in six patients with non-autoimmune, insulin-requiring diabetes diagnosed during the first year of life. Five different heterozygous mutations were identified: c.149G>C (p.R50P), c.175G>A (p.V59M), c.509A>G (p.K170R), c.510G>C (p.K170N), and c.601C>T (p.R201C) in eight patients with diabetes diagnosed between day 3 and 182. Mutations at Arg50 and Lys170 residues are novel. Four patients also presented with motor and/or developmental delay as previously reported. We conclude that KCNJ11 mutations are a common cause of PNDM either in isolation or associated with developmental delay. Permanent diabetes of non autoimmune origin can present up to 6 months from birth in individuals with KCNJ11 and EIF2AK3 mutations. Therefore, we suggest that the acronym PNDM be replaced with the more comprehensive permanent diabetes mellitus of infancy (PDMI), linking it to the gene product (e.g., GCK-PDMI, KCNJ11-PDMI) to avoid confusion between patients with early-onset, autoimmune type 1 diabetes.     

Secretion of vascular endothelial growth factor/vascular permeability factor from human luteinized granulosa cells is human chorionic gonadotrophin dependent

Vascularization is a prominent event during corpus luteum formation, providing low density lipoproteins for steroid biosynthesis and enabling transport of secreted steroids. The process of vascularization is controlled by specific regulators. Vascular endothelial growth factor (VEGF), otherwise named vascular permeability factor (VPF), induces endothelial cell proliferation as well as angiogenesis in vivo and increases capillary permeability. Here we report the expression of VEGF/VPF mRNA by cultured human luteinized granulosa cells (GC) for at least 10 days. Without HCG VEGF/VPF expression declined after day 4 and by day 10 was reduced to approximately 30% of the value at day 4. However, after culture in the presence of 1 U/ml human chorionic gonadotrophin (HCG), expression of VEGF/VPF mRNA by GC was four times greater than control experiments by day 10, and increased 100% from day 4 to day 10. Simultaneously, HCG supplementation increased VEGF/VPF secretion by GC. Medium VEGF/VPF on day 3 was 13 pM without and 11 pM with HCG. Medium VEGF/VPF on day 10 was 6 pM without HCG and 29 pM with HCG. These results suggest that vascularization of the corpus luteum is induced by HCG-mediated effects of VEGF/VPF.