突触功能必需基因参与线虫衰老的调控(英文)

目的鉴定参与线虫衰老的神经内分泌调控的新基因。方法鉴于神经系统在衰老调控中的重要作用,通过寿命分析和脂褐质自发荧光的检测,从编码突触蛋白的遗传位点中筛选参与衰老调控的基因。我们还进一步检查了这些遗传位点相应的突变体的永久性幼虫形成情况,探讨它们是否可能受胰岛素样信号通路的调控。结果遗传位点 unc-10,syd-2,hlb-1,dlk-1,mkk-4,scd-2,snb-1,ric-4,nrx-1,unc-13,sbt-1,unc-64 可能参与线虫衰老的调控。而且在衰老的调控中,unc-10,syd-2,hlb-1,dlk-1,mkk-4,scd-2,snb-1,ric-4,nrx-1 的功能可能与unc-13,sbt-1,unc-64相反。肠道脂褐质自发荧光的检测进一步证明了筛选出的各基因对应突变体的长寿或短寿表型,是由减慢或缩短的组织衰老所致。在筛选出的基因中,syd-2,hlb-1,mkk-4,scd-2,snb-1,ric-4,unc-64 也参与了永久性幼虫形成的调控。另外,daf-2突变增强了syd-2和hlb-1的表达,降低了mkk-4,nrx-1,ric-4,sbt-1,rpm-1,unc-10,dlk-1,unc-13 的表达。daf-16突变提高了syd-2和 hlb-1 的表达,降低了mkk-4,nrx-1,sbt-1,rpm-1,unc-10,dlk-1,unc-13 的表达. 结论突触功能可能在个体寿命和永久性幼虫形成的调控机制中具有重要的作用。     

Use of insulin glargine during pregnancy: a case-control pilot study

OBJECTIVE: To determine whether the use of insulin glargine during pregnancy is associated with an increase in the incidence of fetal macrosomia or adverse neonatal outcome. DESIGN: A matched case-control study. SETTING: Women's Centre, John Radcliffe Hospital, Oxford, UK. SAMPLE: Sixty-four pregnant women treated with insulin during their pregnancies, 20 with type I diabetes and 44 with gestational diabetes. METHODS: Two groups of women were compared in matched pairs. A study group of 32 pregnant women with diabetes treated with insulin glargine during their pregnancy and a control group of 32 pregnant women treated with an intermediate-acting human insulin (isophane or insulin zinc suspension) and matched for weight at booking, height, gestation at delivery, parity, fetal sex, duration of insulin use in pregnancy and glycaemic control during the third trimester of pregnancy (glycosylated haemoglobin [HbA(1c)] concentration and mean blood glucose concentration). MAIN OUTCOME MEASURES: Birthweight, centile birthweight, the incidence of fetal macrosomia (birthweight > 90th percentile) and neonatal morbidity in the two study groups. RESULTS: There was no significant difference between the birthweight or centile birthweight of babies born to the women treated with insulin glargine during pregnancy and that of the babies born to those in the control group treated with intermediate-acting human insulin. The overall incidence of fetal macrosomia was 12/32 (37.5%) in the insulin glargine group and 13/32 (40.6%) in the control group. There was no significant difference in neonatal morbidity between the groups. CONCLUSIONS: The results of this pilot study indicate that insulin glargine treatment during pregnancy does not appear to be associated with increased fetal macrosomia or neonatal morbidity.     

Altered islet Beta-cell function before the onset of Type 1 (insulin-dependent) diabetes mellitus

Summary To define the glucose to insulin dose-response relationship before the onset of diabetes, we studied 22 nondiabetic co-twins of patients with Type 1 (insulin-dependent) diabetes mellitus and nine control subjects. All had intravenous glucose tests at 0.02, 0.1 and 0.5 g/kg and were followedup prospectively for at least 6 years. Seven twins developed diabetes a mean of 7 months later; the remaining 15 are now unlikely to develop diabetes. The seven pre-diabetic twins had higher fasting insulin levels than control subjects (4.2±2.0 vs 1.8±1.8 nmol/l; p<0.05); but lower glucose clearance (1.0±0.5 vs 1.9±0.7 %/min; p<0.05), first phase insulin response at 0.5 g/kg (21.1±23.2 vs 143±50 nmol/l; p<0.0001), and total insulin responses at 0.1 g/kg (p<0.05) and 0.5 g/kg (p<0.00005). Using a curve-fitting programme, the normal glucose to insulin relationship was lost in prediabetic twins who had lower coefficient of determination (R²) than control subjects (p<0.01). In contrast, 15 low-risk twins and their nine control subjects had similar fasting glucose and insulin levels, glucose clearance, R² and insulin secretory responses to different glucose loads. The positive predictive values of subnormal R² and subnormal first phase insulin response were 67 % and 58 % respectively. These observations demonstrate an altered glucose to insulin dose-response relationship and loss of maximum insulin secretory response to glucose before the onset of Type 1 diabetes.     

国产圣唐型胰岛素泵的研制及临床应用

胰岛素泵是胰岛素强化治疗的理想手段。为此，我们采用了双微处理器进行互测和自测，共同控制电机使精密丝杆丝母推动注射器输注胰岛素药液的原理研制了国产胰岛素泵；本仪器具有输注精度高、可靠性大、中文操作界面、使用方便等特点。临床观察证明用此国产胰岛素泵治疗糖尿病具有安全、稳定、效果好的优点。     

甲状腺功能亢进症患儿合并糖代谢紊乱10例临床分析

目的：探讨儿童甲亢患者糖代谢紊乱的特点。方法：用SUPER GLUCOCARD^TM血糖仪和放射免疫方法检测29例甲亢患儿餐前、餐后60min、120min血糖和餐前、餐后60min胰岛素、C肽、胰高糖素、皮质醇及T3、T4、TSH、TGA、TMA（其中10例糖耐量减低为甲亢1组，另19例糖耐量正常为甲亢2组），并与20例健康儿童进行比较。结果：（1）34．5％甲亢患儿出现糖代谢紊乱，病程大于1年和小于1年糖代谢紊乱发生率为50％，9％（P＜0．05）。（2）甲亢1组餐后60min胰岛素、胰岛素／血糖、胰岛素／胰高糖素显著升高（P＜0．05）。结论：甲亢儿童存在糖代谢紊乱现象，表现为葡萄糖耐量减低和胰岛素拮抗，其发生与病程有关，病程较长，发生率较高。糖代谢紊乱可能与自身免疫、胰岛β细胞功能受损及胰岛素拮抗有关。     

Nitric oxide is not involved in the initiation of insulin secretion from rat islets of Langerhans

Summary The involvement of nitric oxide as an intracellular messenger in the control of insulin secretion from pancreatic Beta cells was studied in rat islets of Langerhans by measuring: (i) nitric oxide generation in response to physiological insulin secretagogues; (ii) the effects of inhibitors of nitric oxide synthesis on insulin secretory responses to physiological secretagogues, and on insulin synthesis; (iii) changes in islet cyclic guanosine monophosphate in response to secretagogues; (iv) the effects of exogenous cyclic guanosine monophosphate and dibutyryl cyclic guanosine monophosphate on insulin secretion from electrically permeabilised islets and from intact islets, respectively. These studies produced no evidence that nitric oxide generation is required for the initiation of insulin secretion by common secretagogues. However, the results of our experiments suggest that the generation of nitric oxide may be involved in long-term, glucose-dependent increases in cyclic guanosine monophosphate content of islet cells, although the physiological relevance of these changes requires further investigation.     

Hyperglycaemia compensates for the defects in insulin-mediated glucose metabolism and in the activation of glycogen synthase in the skeletal muscle of patients with Type 2 (non-insulin-dependent) diabetes mellitus

Summary Insulin resistance and a defective insulin activation of the enzyme glycogen synthase in skeletal muscle during euglycaemia may have important pathophysiological implications in Type 2 (non-insulin-dependent) diabetes mellitus. Hyperglycaemia may serve to compensate for these defects in Type 2 diabetes by increasing glucose disposal through a mass action effect. In the present study, rates of whole-body glucose oxidation and glucose storage were measured during fasting hyperglycaemia and isoglycaemic insulin infusion (40 mU·m^–2min^–1, 3 h) in 12 patients with Type 2 diabetes. Eleven control subjects were studied during euglycaemia. Biopsies were taken from the vastus lateralis muscle. Fasting and insulin-stimulated glucose oxidation, glucose storage and muscle glycogen synthase activation were all fully compensated (normalized) during hyperglycaemia in the diabetic patients. The insulin-stimulated increase in muscle glycogen content was the same in the diabetic patients and in the control subjects. Besides hyperglycaemia, the diabetic patients had elevated muscle free glucose and glucose 6-phosphate concentrations. A positive correlation was demonstrated between intracellular free glucose concentration and muscle glycogen synthase fractional velocity insulin activation (0.1 mmol/l glucose 6-phosphate: r=0.65, p<0.02 and 0.0 mmol/l glucose 6-phosphate: r= 0.91, p<0.0001). In conclusion, this study indicates an important role for hyperglycaemia and elevated muscle free glucose and glucose 6-phosphate concentrations in compensating (normalizing) intracellular glucose metabolism and skeletal muscle glycogen synthase activation in Type 2 diabetes.     

Insulin binding to trophoblast plasma membranes and placental glycogen content in well-controlled gestational diabetic women treated with diet or insulin,in well-controlled overt diabetic patients and in healthy control subjects

Summary Insulin binding to trophoblast plasma membranes and the placental glycogen content were measured in twelve healthy women, in eleven well-controlled gestational diabetic women who were treated either with diet alone (n=4) or with insulin (n=7) and in 18 women with well-controlled overt diabetes mellitus (six White B; four White C; eight White D). The competitive binding assay was carried out with 22 concentrations of unlabelled insulin. Binding data were analysed by a non-linear direct model fitting procedure assuming one non-cooperative binding site. Maximum specific binding was unchanged in the total collective of gestational diabetic women, but was decreased by 30% in those treated with diet (6.2±2.2%) and increased by 90% in insulin-treated women (16.4±10.2%) as compared to the control subjects (8.7±2.5%). The diet-treated women had only 40% as many and those treated with insulin had more than twice as many receptors compared to control subjects on a per mg protein basis and if expressed per total placenta. In patients with overt diabetes mellitus maximum specific binding (18.5±10.6 %) was higher (p<0.05) due to more receptors compared to control subjects but was similar to the insulin-treated gestational diabetic patients. Maximum specific binding and receptor concentrations did not correlate linearly with maternal plasma insulin levels. Receptor affinities were virtually similar in all groups (1.8·10⁹ l/mol). The placental glycogen content was reduced (p<0.05) to about 80% of that of control subjects in the diet-treated collective, whereas it was unchanged compared to control subjects in the insulin-treated gestational diabetic women despite a 40% increase (p<0.001) of the maternal-to-cord serum glucose ratio. In overt diabetic patients the maternal-to-cord serum glucose ratio and the placental glycogen content were higher (p<0.05) than in the control subjects. We conclude that trophoblast plasma membranes from gestational diabetic women treated with diet alone express less and those from women treated with insulin express more insulin receptors than those from a healthy control group in vitro. These differences could not have been disclosed without consideration of the mode of treatment. Trophoblast plasma membranes from overt diabetic women have more insulin receptors than those from healthy control subjects.     

Acute actions of insulin-like growth factor II on glucose metabolism in adult rats

Summary The metabolic potency of recombinant human insulin-like growth factor II was studied in anaesthetized adult rats by obtaining dose-response curves for the hypoglycaemic action and for the stimulation of glucose metabolism during euglycaemic clamping. Compared to insulin, about 50 times higher doses of insulin-like growth factor II were required to result in identical in vivo responses, with half-maximally effective serum concentrations for the stimulation of glucose disposal during clamp studies of about 0.8 and 50 pmol/ml, respectively. A similar difference in potency was observed for the dose-dependent stimulatory actions on glucose metabolism in individual target tissues. Half-maximally effective serum concentrations in the range of 0.8 to 3.0 pmol/ml for insulin and of 40 to 70 pmol/ml for insulin-like growth factor II were seen to be required for 2-deoxyglucose uptake, glycogen formation in skeletal muscle and lipogenesis in epididymal fat. Maximal responses were identical with both peptides. These data suggest that in vivo acute metabolic actions of insulin-like growth factor II on carbohydrate metabolism occurred through insulin receptors.     

高血压病患者血清瘦素含量与胰岛素抵抗水平的相关性研究

目的：探讨高血压病患者血清瘦素水平与胰岛素抵抗的关系。方法：测定217例高血压病患者(男92例，女125例)的空腹血清瘦素含量、空腹血糖、胰岛素、收缩压、舒张压和体质量指数(BMI)，稳态模式评估法计算胰岛素抵抗指数(HOMA-IR)。分析瘦素与其他各项参数的相关性。结果：以HOMA—IR的25％位点，作为判断胰岛素抵抗的切割点，把高血压病患者分为胰岛素抵抗组(IR)和胰岛素敏感组(IS)，血清瘦素浓度IR组显著高于IS组(P＜0．05)。血清瘦素浓度与HOMA—IR呈显著正相关(男性r＝0．407，P＜0．01；女性r＝0．254，P＜0．01)；校正年龄和BMI后，男性组两者仍呈显著正相关(r＝0．219，P＜0．05)，女性组两者无相关；逐步回归分析显示，男性组HOMA—IR为血清瘦素浓度的独立预测因素。结论：男性高血压病患者血清瘦素浓度与胰岛素抵抗直接相关，女性则无直接相关性。性别差异的机制有待进一步探讨。