高脂饮食诱导肥胖大鼠胰腺中蛋白酪氨酸磷酸酶1B的表达和活性增高

目的：观察不同时间肥胖大鼠胰腺组织中蛋白酪氨酸磷酸酶1B（PTP-1B）的表达和活性变化，以及其底物蛋白IR和IRS-1经胰岛素刺激后磷酸化程度的变化，探讨肥胖大鼠胰岛胰岛素抵抗发生的可能机制。     

吡格列酮对高脂饮食诱导的胰岛素抵抗大鼠肝组织蛋白酪氨酸磷酸酶-1B及胰岛素受体底物-2表达的影响

目的 观察毗格列酮对高脂饮食诱导的IR大鼠肝组织蛋白酪氨酸磷酸酶-1B（PTP-1B）及胰岛素受体底物-2（IRS-2）表达的影响。方法40只SD大鼠随机分为高脂饮食（HF）组30只和正常对照（Nc）组10只,其中HF组又分为高脂对照（HFN）亚组和毗格列酮（HFP）亚组,每组各15只。喂养12周后,HFP亚组给予吡格列酮灌胃2周,并测定大鼠体重、FPG、Fins、TG、TC、IS。应用免疫组化、免疫印迹、免疫沉淀技术检测肝组织PTP-1B及IRS-2的表达。结果免疫组化：HFN亚组PTP-1B表达较NC组增高（P〈0．01）,HFP亚组较HFN亚组降低（P〈0．01）;免疫印迹：HFN、HFP亚组PTP-1B表达均高于NC组（P〈0．01或P〈0．05）,且HFP亚组低于HFN亚组（P〈0．01）;免疫沉淀：HFN亚组IRS-2磷酸化程度较NC组降低（P〈0．01）,HFP亚组较HFN亚组增高（P〈0．05）。结论吡格列酮能够改善IR,其作用机制可能与抑制PTP-1B表达,从而使胰岛素信号转导分子IRS-2表达增强有关。     

蛋白酪氨酸磷酸酶1B在肥胖大鼠下丘脑的表达

目的观察高脂饲料诱导的肥胖大鼠下丘脑蛋白酪氨酸磷酸酶1B（PTP-1B）的表达。方法SD大鼠20只随机分为正常饲料组和高脂饲料组喂养8周。测定大鼠Fins、BG、TG、TC、瘦素、副睾脂肪垫重量、PTP-1B活性;观察肝脏形态学改变;蛋白印迹法检测下丘脑组织中PTP-1B蛋白含量。结果（1）高脂组胰岛素敏感性降低,出现瘦素抵抗和肝脏脂肪变性;（2）高脂组大鼠下丘脑PTP-1B蛋白表达和活性增加。结论高脂饲料可诱导大鼠下丘脑PTP-1B蛋白表达和活性升高,这可能是肥胖引发下丘脑产生胰岛素抵抗和瘦素抵抗的机制之一。     

Exendin-4改善胰岛素抵抗的作用机制研究

目的探讨exendin-4（exenatide）对高脂诱导胰岛素抵抗（IR）大鼠胰岛素敏感性（IS）改善的机制及对脂肪细胞因子的影响。方法健康雄性SD大鼠随机分为正常饮食组（NC）、高脂组（HF）和高脂＋Exenatide组（HE）。HE组给予exenatide（2μg／kg，Et二次）腹腔注射6周，用静脉胰岛素耐量试验评价各组IS变化，观察各组肌肉和脂肪组织胰岛素信号传导、脂肪细胞因子表达和血浆浓度变化。结果6周后，HE组Lee＇s指数、空腹血浆FFA、TG、TC均较NC组降低（P均〈0．01），IR明显改善；胰岛素刺激后HE组肌肉和脂肪组织IRS-1酪氨酸磷酸化升高（P〈0．05）；HF和HE组血浆内脏脂肪素（visfatin）水平明显降低（P〈0．05，P〈0．01），但HE组脂联素（APN）血浆水平和脂肪组织mRNA表达明显高于HF和NC组（P均〈0．01）。结论Exenatide明显改善了高脂大鼠IR，其胰岛素增敏机制可能与增强IRS-1酪氨酸磷酸化以及对APN、visfatin等脂肪细胞因子的影响有关。     

mTOR／S6K1信号通路在高脂饮食诱导小鼠胰岛素抵抗发生中的作用

目的探讨mTOR及其下游效应因子S6K1在胰岛素抵抗（IR）发生中的作用。方法C57BL／6雄性小鼠20只随机平均分为正常饮食组（NC组）和高脂饮食组（HF组）。后者喂养14周后建立IR模型。检测两组血清胰岛素水平和葡萄糖耐量,显微镜下观察胰岛形态学变化;检测骨骼肌中mTOR和S6K1mRNA的表达,以及mTOR、S6K1和其磷酸化水平蛋白的表达。结果与NC组相比,HF组小鼠表现出明显的IR症状,其体重和空腹胰岛素分别升高了21．99％（P〈0．05）和181．82％（P〈0．01）;胰岛8细胞团面积也显著增加,糖耐量明显受损,骨骼肌细胞中mTOR mRNA和蛋白分别升高了25．61％（P〈0．05）和37．41％（P〈0．01）,S6K1 mRNA和蛋白分别升高了54．98％（P〈0．01）和37．36％（P〈0．01）,S6K1磷酸化水平蛋白表达在高脂饮食后升高了680．15％（P〈0．01）。结论mTOR／S6K1信号通路与高脂饮食诱导IR的发生密切相关。     

辛伐他汀对胰岛素抵抗大鼠肝脏NF-κB p65表达的影响

目的探讨辛伐他汀（SV）对胰岛素抵抗（IR）大鼠肝脏NF-κB p65表达的影响。方法采用高脂饲料喂养建立IR大鼠模型，并用正常血糖-高血浆胰岛素钳夹技术评估，IR大鼠给予SV治疗。应用Western blot方法检测大鼠肝脏中NF-κB p65蛋白的表达。结果（1）高脂饲料组的葡萄糖输注率明显低于基础饲料组（P〈0．01）。（2）SV治疗组肝脏NF-κB p65蛋白的表达明显低于高脂未治疗组（P〈0．05），但与基础饲料组无明显差别。（3）与基础饲料组相比，SV治疗组和高脂未治疗组的胰岛素敏感性指数（ISI）明显降低（P〈0．05）；SV治疗组与高脂未治疗组的ISI无明显差别。结论SV能使高脂诱导的IR大鼠肝脏升高的NF-κB p65蛋白表达水平恢复正常，但不能明显改善全身胰岛素抵抗。     

多囊卵巢综合征患者卵巢黄素化颗粒细胞胰岛素受体底物1、2表达及其酪氨酸磷酸化

目的检测多囊卵巢综合征（PCOS）患者卵巢黄素化颗粒细胞胰岛素受体底物（IRS）-1、IRS-2蛋白表达及其酪氨酸磷酸化水平，探讨卵巢局部胰岛素抵抗的分子机制。方法收集行体外受精-胚胎移植治疗的11例PCOS患者（PCOS组）和15例排卵正常的输卵管性不孕患者（对照组）促排卵后卵巢黄素化颗粒细胞，采用放射免疫法检测血清LH、FSH、睾酮及空腹胰岛素（FINS）水平；采用葡萄糖氧化酶法测定空腹血糖（FPG）水平；利用稳态模型（HOMA）计算胰岛素抵抗指数（HOMA—IR）；采用RT—PCR、Western印迹及免疫沉淀法分别检测两组卵巢黄素化颗粒细胞IRS-1和IRS-2 mRNA、蛋白的表达及其酪氨酸磷酸化程度。结果（1）PCOS患者血清LH、LH／FSH、睾酮、FINS及HOMA—IR均明显高于对照组（均P〈0．05）；（2）与对照组比较，PCOS患者卵巢黄素化颗粒细胞IRS-1 mRNA、蛋白的表达显著增加（均P〈0．05），IRS-2 mRNA、蛋白的表达显著降低（均P〈0．05）；（3）PCOS患者卵巢黄素化颗粒细胞IRS-1和IRS-2酪氨酸磷酸化程度均较对照组明显降低（均P〈0．05）。结论PCOS患者卵巢局部存在胰岛素抵抗，其原因可能与IRS-1和IRS-2蛋白表达及其酪氨酸磷酸化异常有关。     

高脂饮食对大鼠脂肪肝胰岛素受体底物1、2表达的影响

目的探讨高脂饮食对大鼠脂肪肝胰岛素受体底物（IRS）1、IRS-2分子表达的影响。方法对8周高脂饲养（n=7）和正常饲养（n=7）大鼠的胰岛素敏感性、脂质代谢、肿瘤坏死因子（TNF）α以及肝脏IRS-1、IRS-2的mRNA和蛋白表达进行检测。结果与正常组比，高脂组大鼠呈现胰岛素抵抗，游离脂肪酸（FFA）和TNF-α增高；肝脏的IRS-1 mRNA和蛋白含量分别降低了28％和32％（P〈0．01），IRS-2mRNA和蛋白含量分别降低了30％和27％（P〈0．01）。结论高脂饮食导致大鼠肝脏IRS-1、IRS-2的mRNA和蛋白含量明显降低，这可能是高脂饮食引起脂肪变肝脏胰岛素抵抗的重要分子机制。     

PTP-1B 及 IRS-1在慢性间歇低氧大鼠肝细胞中的表达

目的：探讨慢性间歇低氧(CIH)对大鼠肝细胞蛋白酪氨酸磷酸酶-1B(protein tyrosine phosphatase-1B,PTP-1B)及胰岛素受体底物-1(insulin receptor substrate-1,IRS-1)蛋白表达量的影响及其导致胰岛素抵抗发生的可能机制。方法选取健康雄性 SD 大鼠24只,按随机数字表法分为正常对照组(NC 组)、慢性间歇低氧4周组(CIH4组)、慢性间歇低氧8周组(CIH8组),每组8只。NC 组无间歇低氧暴露正常饲养,CIH4组及 CIH8组于上午9时至下午5时放入间歇低氧仓暴露于间歇低氧环境中,舱内最低氧浓度为6%~7%。分别于第4周及第8周检测大鼠空腹血糖及空腹胰岛素水平,用稳态模型胰岛素抵抗指数(HOMA-IR)以及胰岛素敏感指数(insulin sensitive index,ISI)评价胰岛素抵抗, SABC 法免疫组织化学试剂盒检测 CIH 大鼠肝细胞 PTP-1B 及 IRS-1蛋白表达,以平均灰度值表示PTP-1B 及 IRS-1的蛋白表达量,并做统计学分析。结果与 NC 组比较,CIH4组及 CIH8组空腹血糖、空腹胰岛素及 HOMA-IR 升高,ISI 降低,差异有统计学意义(P <0.05),且 CIH8组更为显著;与 NC 组相比较,CIH4组及 CIH8组 PTP-1B 蛋白表达增加,IRS-1蛋白表达减少,差异有统计学意义(P <0.05),Pearson 相关分析显示,HOMA-IR 与 PTP-1B 平均灰度值呈负相关、与 IRS-1平均灰度值呈正相关;ISI 与 PTP-1B 平均灰度值呈正相关、与 IRS-1平均灰度值呈负相关。结论①CIH 暴露使大鼠空腹血糖及胰岛素水平升高且发生胰岛素抵抗,随着 CIH 暴露时间的延长,胰岛素抵抗程度加重。②CIH 导致大鼠肝细胞 PTP-1B 蛋白表达增加,IRS-1蛋白表达减少,PTP-1B 及 IRS-1可能共同参与了 CIH 大鼠胰岛素抵抗的发生发展。     

蜕皮甾酮对2型糖尿病大鼠肝细胞IR S-2蛋白表达的影响

目的：探讨蜕皮甾酮对2型糖尿病大鼠肝细胞胰岛素受体底物2（ IRS-2）蛋白表达的影响。方法选择42只大鼠,14只作为正常组,常规饲料喂养,余下28只先以高脂喂养加小剂量STZ注射诱导2型糖尿病大鼠模型,造模成功后,随机分为模型组和治疗组,分别给予高脂饲料喂养、高脂饲料喂养＋蜕皮甾酮灌胃治疗。5周后取大鼠肝组织标本,应用免疫组化和RT-PCR技术检测IRS-2蛋白和mRNA含量。结果正常组和治疗组肝细胞IRS-2蛋白及mRNA含量均明显高于模型组（ P＜0．05或＜0．01）。结论蜕皮甾酮可提高2型糖尿病大鼠肝细胞IRS-2蛋白和mRNA含量,这可能是蜕皮甾酮改善2型糖尿病大鼠胰岛素抵抗的机制之一。     

胰岛素瘤的解剖分布特点分析

目的胰岛素瘤是最常见的胰腺神经内分泌肿瘤，因其临床表现多样，导致诊断困难。影像学诊断尤其是超声内镜(EUS)在胰岛素瘤的诊断中起着重要作用，拥有较高的敏感性和特异性。本研究拟通过明确胰岛素瘤的解剖分布特点，以期有助于提高影像学的诊断准确率和降低漏诊率，尤其是在教育和培训实践中对于EUS的学习者更具有指导价值。 方法回顾性分析解放军总医院第一医学中心病案资料数据库1993年1月至2019年11月经外科手术、病理确诊为胰岛素瘤的患者的临床资料，检索方法采取搜索术后病理诊断为"胰岛素瘤"的病例，通过查阅病例的方法，提取出胰岛素瘤的大小和解剖分布等数据，进一步分析其特点。 结果共检索到确诊为胰岛素瘤的患者116例，其中，男45例、女71例，年龄13～76岁，平均年龄(44.4±14.85)岁。胰岛素瘤单发110例(94.8%)、多发6例(5.2%)。位置分布：头颈部46例(39.7%)，单发45例、多发1例；体尾部68例(58.6%)，单发65例、多发3例；全胰腺多发2例(1.7%)。病变大小特点：最大径0.4～3.4 cm，平均大小(1.53±0.58)cm。≤1 cm 29例、>1 cm而≤1.5 cm41例、>1.5 cm而≤2.0 cm28例，≤3 cm 15例，>3 cm 3例。年龄与肿瘤的大小相关，≤44岁患者肿瘤平均大小为(1.36±0.51)cm、>44岁患者肿瘤平均大小为(1.70±0.60)cm，P<0.05。头颈部的肿瘤大于体尾部的肿瘤，头颈部肿瘤平均大小(1.66±0.63)cm，体尾部(1.42±0.52)cm，P<0.05。 结论胰岛素瘤在胰腺体尾部较头颈部更好发；绝大多数单发，但可以全胰腺多发；多数小于1.5 cm，肿瘤的大小与患者年龄和肿瘤的解剖分布相关。     

Pathogenesis of carcinoma of the papilla of Vater

Most adenomas and carcinomas of the small intestine and extrahepatic bile ducts arise in the region of the papilla of Vater. In familial adenomatous polyposis (FAP) it is the main location for carcinomas after proctocolectomy. In many cases symptoms due to stenosis lead to diagnosis at an early tumor stage. In about 80%, curative intended resection is possible. Operability is the most relevant prognostic factor. Most ampullary carcinomas resp. carcinomas of the papilla of Vater develop from adenomatous or flat dysplastic precursor lesions. They can be sited in the ampulloduodenal part of the papilla of Vater, which is lined by intestinal mucosa. They also can develop in deeper parts of the ampulla, which are lined by pancreaticobiliary duct mucosa. Intestinal-type adenocarcinoma and pancreaticobiliary-type adenocarcinoma represent the main histological types of ampullary carcinoma. Furthermore, there exist unusual types and undifferentiated carcinomas. Many carcinomas of intestinal type express the immunohistochemical marker profile of intestinal mucosa (keratin 7?, keratin 20+, MUC2+). Carcinomas of pancreaticobiliary type usually show the immunohistochemical profile of pancreaticobiliary duct mucosa (keratin 7+, keratin 20?, MUC2?). Even poorly differentiated carcinomas, as well as unusual histological types, may conserve the marker profile of the mucosa they developed from. These findings underline the concept of histogenetically different carcinomas of the papilla of Vater which develop either from intestinal- or from pancreaticobiliary-type mucosa of the papilla of Vater. Molecular alterations in ampullary carcinomas are similar to those of colorectal as well as pancreatic carcinomas, although they appear at different frequencies. In future studies, molecular alterations in ampullary carcinomas should be correlated closely with the different histologic tumor types. Consequently, the histologic classification should reflect the histogenesis of ampullary tumors from the two different types of papillary mucosa.     

Demonstration of the mechanism of action of biguanides

Summary Palmitic acid oxidation in rat diaphragm homogenate is depressed by biguanide concentrations that are still incapable of inhibiting oxidative phosphorylation. Glucose oxidation is not directly effected by the same biguanide concentrations: however, the inhibitory effect of palmitic acid on glucose oxidation is partly removed by biguanides. Inhibition of fatty acid oxidation, which accounts for most of the metabolic effects caused by these drugs, can be regarded as the fundamental mechanism of action of biguanides. There is some evidence suggesting that these drugs might interact with carnitine, thus preventing long-chain fatty acids from being transported across the mitochondrial membrane to the site of oxidation. Traduzione a cura degli AA.     

Lack of correlation of degree of villous atrophy with severity of clinical presentation of coeliac disease

BACKGROUND AND AIM: Both the clinical presentation and the degree of mucosal damage in coeliac disease vary greatly. In view of conflicting information as to whether the mode of presentation correlates with the degree of villous atrophy, we reviewed a large cohort of patients with coeliac disease. PATIENTS AND METHODS: We correlated mode of presentation (classical, diarrhoea predominant or atypical/silent) with histology of duodenal biopsies and examined their trends over time. RESULTS: The cohort consisted of 499 adults, mean age 44.1 years, 68% females. The majority had silent coeliac disease (56%) and total villous atrophy (65%). There was no correlation of mode of presentation with the degree of villous atrophy (p=0.25). Sixty-eight percent of females and 58% of males had a severe villous atrophy (p=0.052). There was a significant trend over time for a greater proportion of patients presenting as atypical/silent coeliac disease and having partial villous atrophy, though the majority still had total villous atrophy. CONCLUSIONS: Among our patients the degree of villous atrophy in duodenal biopsies did not correlate with the mode of presentation, indicating that factors other than the degree of villous atrophy must account for diarrhoea in coeliac disease.     

血吸虫童虫生长发育及其机制的研究进展

血吸虫童虫是宿主免疫系统攻击的重要靶标,包括皮肤型、肺型和肝门型童虫。宿主分子对童虫生长发育具有重要作用。童虫生长发育机制包括免疫调节、信号转导、性别发育及凋亡等。肌动蛋白、组织蛋白酶、烯醇化酶和葡萄糖基转移酶等分子为血吸虫童虫生长发育的重要分子。本文对血吸虫童虫生长发育及其机制的研究进展做一综述。     

124例耐多药结核分枝杆菌基因突变特征分析

目的对临床分离的耐多药结核分枝杆菌相关基因的突变特征进行分析。方法对124例耐多药结核分枝杆菌以及50株敏感株的耐药相关基因(包括异烟肼inh A、kat G、oxyR-ahp C间隔区以及利福平rpo B)进行序列测定,分析其基因突变情况。结果异烟肼耐药inh A基因突变率为14.5%;kat G基因突变率为70.2%(87/124),主要位于315位;oxyR-ahp C间隔区突变率为15.3%;inh A、kat G两种基因同时突变率75.0%,三种基因同时突变率为89.5%。利福平rpo B基因突变的检出率高达95.2%,突变主要发生在531、526、516位点。结论我省耐多药菌异烟肼耐药相关基因最常见突变为kat G 315、inh A C-T(-15)、axyR-ahp C间隔区(-10)C-T,利福平为rpo B531、526、516。结合MDR-TB耐药相关基因的特征分析,可以建立一种快速、准确、特异的适合于我省的检测结核菌耐多药性的新方法。     

氯硝柳胺悬浮剂的毒性评价

目的评价氯硝柳胺悬浮剂的毒性，为现场大规模应用灭螺提供依据。方法按照中华人民共和国国家标准GB 15670-1995《农药登记毒理学试验方法》和鱼类毒性试验方法进行。结果经口、经皮肤的LDso雌、雄性大鼠均>5 000 mg/kg，经呼吸道的LCso雌、雄性大鼠均>5 000mg/m3，该药经口、经皮肤、经呼吸道毒性均属微毒类药物；兔眼用药后，观察期内无不良反应，对眼无刺激性；皮肤用药后对皮肤无刺激性。与氯硝柳胺原药、氯硝柳胺乙醇胺盐原药和氯硝柳胺乙醇胺盐可湿性粉剂相比，氯硝柳胺悬浮剂对鱼急性毒性最低。结论氯硝柳胺悬浮剂属微毒类药物，对鱼的毒性低于其乙醇胺盐可湿性粉剂，适合于现场应用。     

Assessment of quality of life of parents of children with juvenile chronic arthritis

The aim of the study was to assess the quality of life (QOL) and the psychological status of parents of children with juvenile chronic arthritis (JCA). The QOL, anxiety and depression of the parents of 28 children with JCA were evaluated and compared to those of the parents of 28 healthy children. Mothers of JCA children and mothers of healthy children reported similar QOL. The reported anxiety and depression levels were similar for mothers and fathers in both groups. The parents of children with pauciarticular-type JCA reported lower QOL and higher levels of anxiety and depression than the parents of children with other types, namely polyarticular and systemic JCA. These findings may be explained by the fact that the pauciarticular patients had shorter disease duration and were less frequently seen in the outpatient clinic. The QOL of mothers of children with JCA was found to be slightly impaired in the group of children with pauciarticular JCA. Future larger studies are needed to confirm these results, as the number of subjects in the three groups was rather low. Received: 26 September 2001 / Accepted: 8 February 2002     

Numerical Simulation of the Effect of Rate of Change of Glucose on Measurement Error of Continuous Glucose Monitors

Background

A 5-day in-patient study designed to assess the accuracy of the FreeStyle Navigator® Continuous Glucose Monitoring System revealed that the level of accuracy of the continuous sensor measurements was dependent on the rate of glucose change. When the absolute rate of change was less than 1 mg•dl⁻¹•min⁻¹ (75% of the time), the median absolute relative difference (ARD) was 8.5%, with 85% of all points falling within the A zone of the Clarke error grid. When the absolute rate of change was greater than 2 mg•dl⁻¹•min⁻¹ (8% of the time), the median ARD was 17.5%, with 59% of all points falling within the Clarke A zone.

Method

Numerical simulations were performed to investigate effects of the rate of change of glucose on sensor measurement error. This approach enabled physiologically relevant distributions of glucose values to be reordered to explore the effect of different glucose rate-of-change distributions on apparent sensor accuracy.

Results

The physiological lag between blood and interstitial fluid glucose levels is sufficient to account for the observed difference in sensor accuracy between periods of stable glucose and periods of rapidly changing glucose.

Conclusions

The role of physiological lag on the apparent decrease in sensor accuracy at high glucose rates of change has implications for clinical study design, regulatory review of continuous glucose sensors, and development of performance standards for this new technology. This work demonstrates the difficulty in comparing accuracy measures between different clinical studies and highlights the need for studies to include both relevant glucose distributions and relevant glucose rate-of-change distributions.     

Study of constancy of hydrogen-consuming flora of human colon

The constancy of the hydrogen consuming flora of the human colon was studied in 15 healthy subjects via two measurements obtained 18 to 36 months apart. Hydrogen disappearance rate and the major products of H₂-consuming bacteria, methane and sulfide, were measured during incubation of fecal homogenates with excess hydrogen and sulfate. In 11/15, the hydrogen consumption rate and the predominant hydrogen-consuming pathway (methanogenesis, sulfate reduction, or neither) remained constant. However, major shifts in these pathways were observed in four subjects, with two losing and two gaining the ability to produce methane. Methanogenesis was associated with the highest hydrogen consumption rate. This study demonstrates that clinically unrecognizable, major alterations of the colonic flora occur in healthy subjects. Understanding of the factors responsible for these alterations might allow for therapeutic manipulation of the colonic flora.Supported in part by the Department of Veterans Affairs and NIDDKD RO1 DK 13309-25.