A serum inhibitor of insulin action on muscle

Summary 1. The intraperitoneal assay of insulin activity has been used to detect the presence of an insulin inhibitor in serum. 2. A solution of 5% bovine serum albumin has been established as an injection medium permitting the maximum insulin effectiveness. 3. When insulin was injected intraperitoneally in serum from male rats or male human subjects, the insulin effectiveness on the diaphragm was reduced compared with that of insulin in 5% bovine albumin; whereas that on the epididymal adipose tissue was unaffected. 4. The inhibitory activity was associated with the albumin fraction of the serum; and neither the inhibitory activity of the serum nor that of the albumin derived from the serum was affected by prolonged dialysis. 5. The inhibitory activity was released from the albumin by boiling at pH 4 to 5. The inhibitory substance appears to be a polypeptide of mol. wt between 5000 and 10000.Supported by the Fonds National Suisse de la Recherche Scientifique, Grant No. 3618.     

Weight regain after Roux-en-Y: a significant 20% complication related to PYY

OBJECTIVE: Roux-en-Y gastric bypass (RYGB) produces rapid and dramatic weight loss in very heavy obese patients. Up to 20% cannot sustain their weight loss beyond 2 to 3 y after surgery. METHODS: To identify putative etiologic factors producing post-RYGB weight regain, a literature survey of metabolic changes in very obese and a review of our diet-induced obese RYGB rat model data was done. RESULTS: Weight regain suggests an imbalance in physiologic mechanisms regulating appetite and metabolic rate. Weight regain occurred in 25% of our rats, produced by return to presurgical energy intake levels. The 75% of rats that sustained weight loss secreted a significantly larger amount of peptide YY (PYY) while suppressing leptin secretion; those that failed were unable to develop or sustain a sufficiently large plasma PYY:leptin ratio. Metabolic consequences of this failure included reversal of initial postsurgical increases in peripheral fatty acid oxidation, anorexigenic activity in the hypothalamic arcuate nucleus and paraventricular nucleus, and the expression of uncoupling protein-2 in adipose tissues, and decreases in hepatic lipogenesis, free tri-iodothyronine secretion, expression of orexigenic activity in the arcuate nucleus and paraventricular nucleus, expression of adenosine monophosphate kinase in adipose tissues, skeletal muscle mitochondrial mass, and endocannabinoid content and appetite. CONCLUSION: Weight regain after RYGB occurs in approximately 20% of patients and constitutes a serious complication. Weight regain-promoting consequences are attributed to a failure to sustain elevated plasma PYY concentrations, indicating that combining RYGB with pharmacologic stimulation of PYY secretion in patients after RYGB who exhibit inadequate PYY concentration may increase long-term success of surgical weight reduction in morbidly obese adults.     

The action of a toxin from the sea Anemone Anemonia sulcata upon mammalian heart muscles

Summary The cardiac activity of toxin II, a basic polypeptide (m.w.: 4770) from the sea anemone Anemonia sulcata, was investigated in isolated electrically driven guinea-pig and rat auricles, Langendorff heart preparations of guinea-pigs and cat heart-lung preparations.Low concentrations of toxin II (2–100 nM) evoked a dose-dependent positive inotropic effect in the three different heart muscle preparations investigated.Higher concentrations of toxin II produced toxic symptoms like contracture and arrhythmia in auricles and atria (about 25 nM). In isolated cat hearts high toxin II concentrations (about 160 nM) caused unusual toxic symptoms such as long periods of ventricular fibrillation alternating with periods of normal cardiac activity.In rat and guinea-pig auricles as well as in Langendorff hearts of guinea-pigs the extent and rate of the positive inotropic effect induced by toxin II depended on the extracellular calcium concentration (0.45 to 2.7 mM).Toxin II did not alter the heart rate in spontaneously beating isolated cat hearts.In electrically driven guinea-pig auricles, the rate of the inotropic effect induced by toxin II was accelerated by increasing stimulation frequencies.Toxin II did not change the coronary flow in Langendorff heart preparations of guinea-pigs.Parts of this work were presented at the Spring Meeting of the German Pharmacological Society at Mainz (March, 1975) and at the first meeting of the European Section of the International Society on Toxinology at Paris (October, 1975)     

多肽:N-乙酰氨基半乳糖转移酶2的原核表达、纯化及酶活检测

目的：以人类多肽：N-乙酰氨基半乳糖转移酶2（ppGalNAc-12）为研究对象，利用载体pGEX-5X-3在大肠杆菌（E．Coli）BL21中原核表达其编码序列，并对表达产物进行纯化、复性及酶活检测。方法：首先利用PCR技术从克隆载体pDONR201-T2得到ppGalNAc-T2全长编码序列，将其亚克隆至原核表达载体pGEX-5X-3，形成重组表达质粒pGEX-5X-3／T2。重组质粒转化大肠杆菌DH5α，测序鉴定后转化BL21，异丙基硫代半乳糖（IPTG）诱导后，表达产物为主要以包涵体形式存在的融合蛋白。对其复性后用谷胱甘肽-琼脂糖（Glutathione-Sepharose）4B亲和层析柱进行纯化。然后根据ppGalNAc-T2的催化功能，设计底物，建立酶促反应体系，利用高效液相色谱（HPLC）进行酶活分析。结果：成功构建了原核表达重组载体pGEX-5X-3／T2，通过蛋白质电泳检测到分子量约为90 kD的融合蛋白的表达，利用亲和层析得到纯化的酶蛋白，并经Western印迹得以验证。反应后体系上柱洗脱后出现酶促反应的产物洗脱峰。结论：成功构建了重组表达载体pGEX-5X-3／T2，ppGalNAc-T2伞长编码序列被成功表达、纯化及复性，检测到具有酶活性。     

常用抗癫痫药对大鼠体内Oatp2表达的影响

目的：研究常用抗癫痫药AEDs丙戊酸钠（VPA）、卡马西平（CBZ）、苯妥英钠（PHT）对正常及癫痫大鼠脑、肝内Oatp2表达的影响．方法：采用氯化锂-匹罗卡品诱发Wistar大鼠慢性自发性癫痫（SE），分别予VPA[187．5mg／（kg·d）]，CBZ[125mg／（kg·d）]，PHT[62．5mg／（kg·d）]治疗4wk后，采用免疫组化SABC法检测大鼠脑、肝内Oatp2分布，Western Blot及RT—PCR方法检测Oatp2蛋白及mRNA的表达水平．结果：①脑、肝组织中均可见Oatp2免疫反应阳性物质，分别表达于脑微血管内皮细胞、脉络丛上皮细胞及肝细胞；②与正常对照相比，癫痫大鼠及AEDs治疗大鼠脑内Oatp2蛋白表达均降低，而Oatp2-mRNA表达无明显变化；③癫痫大鼠肝内Oatp2-mRNA与蛋白表达与正常对照组相比无明显变化；而使用CBZ，PHT后大鼠肝内Oatp2-mRNA与蛋白表达上调，使用VPA后肝内Oatp2-mRNA与蛋白表达下调．结论：VPA，CBZ，PHT均可下调脑内Oatp2表达，而对肝内Oatp2的表达变化存在不同影响，AEDs可能通过影响Oatp2表达，影响其自身向脑内的转运和在体内的代谢．     

扇贝多肽对UVB辐射小鼠胸腺淋巴细胞的保护作用

目的：研究扇贝多肽(polypeptide ftom Chlamys，farreri)对中波紫外线(UVB)辐射损伤小鼠胸腺淋巴细胞的保护作用。方法：UVB辐射小鼠胸腺淋巴细胞，MTT法检测胸腺淋巴细胞的活性；酶生化法检测细胞谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性；流式细胞术检测细胞内活性氧(ROS)的产生量以及细胞凋亡率。结果：PCF能明显减轻UVB辐射对小鼠胸腺淋巴细胞的损伤；提高细胞GSH-Px、SOD和CAT活性；降低细胞中ROS的产生量和细胞凋亡率。结论：PCF对小鼠胸腺淋巴细胞具有明显的辐射保护作用。     

喷雾干燥技术在蛋白、多肽类药物微球制备中的应用

按照不同的常用载体材料（聚乳酸类和壳聚糖类），分类综述应用喷雾干燥技术制备蛋白、多肽类药物微球的研究进展，主要介绍和比较了溶液，喷雾干燥、乳剂，喷雾干燥、喷雾冷冻干燥、喷雾液中冷冻及低温喷雾提取等制备工艺的特点。     

龙牡壮骨冲剂对小鼠胃肠动力和血浆血管活性肠肽的影响

目的:通过观察龙牡壮骨冲剂对小鼠胃肠动力和血浆血管活性肠肽(VIP)的影响,以探讨该药对胃肠动力的影响及其机制。方法:将小鼠随机分为对照组、模型组、龙牡壮骨冲剂大剂量组、中剂量组、小剂量组,用胃复安、阿托品、新斯的明、肾上腺素注射液尾静脉注射分别复制胃肠动力紊乱小鼠模型,以营养性半固体糊灌胃,标记并测量胃残留率和小肠推进比,同时以放免法测量血浆VIP水平。结果:胃复安可致胃排空加速,同时胃复安可致血浆VIP水平降低(均为P<0.05)。阿托品可致胃排空减慢,同时可致血浆VIP升高(均P<0.05)。新斯的明可致小肠推进比增加,同时可致血浆VIP降低(均P<0.05)。肾上腺素可致小肠推进比降低并可致血浆MLT降低、VIP升高(均P<0.05)。龙牡壮骨冲剂对正常组小鼠胃残留率和小肠推进比无影响,大剂量龙牡壮骨冲剂对胃复安所致胃排空加速、阿托品所致胃排空减慢、新斯的明所致小肠推进比增加、肾上腺素所致小肠推进比降低有逆转作用(均P<0.05),中小剂量龙牡壮骨冲剂亦有一定的逆转作用。龙牡壮骨冲剂对各组VIP紊乱有逆转作用,且与剂量有一定的相关性。结论:龙牡壮骨冲剂可双向调节胃肠运动,并具有剂量依赖性,其对胃肠动力的调节作用可能是通过影响血液中胃肠激素水平实现的。     

采用TOPO-TA克隆法建立多肽:N-乙酰氨基半乳糖转移酶基因家族cDNA文库

目的：通过实验方法建立多肽N-乙酰氨基半乳糖转移酶基因家族cDNA文库，欲以此为基础对人体不同肿瘤细胞中的该基因家族进行表达谱分析。方法：主要为PCR和TOPO-TA克隆技术。结果：通过电泳图谱初步证实了这一家族的不同成员均已得到有效的扩增，并获得了相应的片段库。结论：多肽：N-乙酰氨基半乳糖转移酶基因家族cDNA被成功扩增，并建立了该基因家族的eDNA文库。     

β淀粉样蛋白与生长因子变化与老年性痴呆致病因素的研究

目的：检测血清β淀粉样蛋白（β－ＡＰ）和多肽生长因子含量变化,探讨其在Ａｌｚｈｅｉｍｅｒ病（ＡＤ）和血管性痴呆（ＶＤ）发病机制中的可能作用。方法：采用放射免疫分析法（ＲＩＡ）检测临床诊断为ＡＤ患者８例,ＶＤ患者１５例及６３例缺血性脑血管病（ＩＣＶＤ）患者血清β－ＡＰ、转化生长因子α（ＴＧＦ－α）和类胰岛素样生长因子Ⅱ（ＩＧＦ－Ⅱ）的水平,同时与健康对照组比较。结果：ＡＤ与ＶＤ患者β－ＡＰ、ＴＧＦ－α和ＩＧＦ－Ⅱ水平明显高于ＩＣＶＤ组和健康对照组,均具有显著性差异。ＩＣＶＤ患者血清β－ＡＰ、ＴＧＦ－α和 ＩＧＦ－Ⅱ水平亦明显高于对照组,其中以脑梗塞后遗症（ＳＣＩ）和椎基底动脉供血不足（ＶＢＩ）组增高十分明显,与对照组比较差异显著（Ｐ＜０．０５）。ＡＤ与 ＶＤ患者 ３项测定指标之间具有明显的正相关。结论：①β－ＡＰ可能是ＡＤ和ＶＤ发病的危险因素。②引起ＡＤ和ＶＤ神经元毒性作用进而导致痴呆．这可能与ＴＧＦ－α和ＩＧＦ－Ⅱ增多有关。③β－ＡＰ与ＴＧＦ－α、ＩＧＦ－Ⅱ密切相关,在老年斑形成过程中可能起重要作用。