脉络丛上皮细胞在脑缺血中的神经保护作用

脉络丛上皮细胞可分泌多种生物活性肽,包括生长因子和神经营养因子,对促进大脑发育、维持大脑形态和功能稳定具有重要作用.此外,脉络丛上皮细胞具有神经干细胞的特性,将其作为移植细胞治疗脑缺血具有合理性.离体实验和动物实验均证实,脉络丛上皮细胞可通过多种机制抗氧化损伤、减少细胞凋亡和抑制炎性反应,从而发挥神经保护作用.文章对脉络丛上皮细胞在脑缺血中的神经保护作用进行了综述.     

星形胶质细胞在脑缺血中的双重作用

星形胶质细胞是中枢神经系统中数量最多的神经细胞,发挥着重要的生理作用.在脑缺血过程中,星形胶质细胞活化是中枢神经系统的主要变化之一.活化的星形胶质细胞可通过维持离子平衡、调节能量代谢、清除兴奋性氨基酸、对抗氧化应激、分泌神经保护物质等机制发挥神经保护作用.然而,脑缺血后星形胶质细胞活化也有其不利的一面.文章对星形胶质细胞活化在脑缺血中的保护与损害作用进行了综述,探讨了其调控机制,旨在为缺血性卒中的治疗提供新的思路.     

激肽释放酶-激肽系统与脑缺血

最近的一些研究表明,脑缺血后激肽释放酶-激肽系统被激活。脑缺血后,转移激肽释放酶基因可通过促进胶质细胞存活和迁移,抑制细胞凋亡,促进血管生存和神经生成提供神经保护效应。研究脑缺血后激肽释放酶-激肽系统的内在作用机制,有望为卒中的治疗和康复提供一条新的思路。     

腺苷酸活化蛋白激酶在脑缺血中的作用及其机制

腺苷酸活化蛋白激酶(AMPK)是一种高度保守的丝氨酸/苏氨酸蛋白激酶,在能量代谢的调控中起重要作用。脑缺血、缺氧后可激活AMPK,活化的AMPK通过抑制氧化应激和炎性反应、激活自噬、减轻细胞凋亡和促进血管生成等机制,减轻脑缺血后的神经功能损伤,从而发挥神经保护作用。作者对AMPK的分子生物学特征及其在脑缺血中的作用及机制进行了综述,目的在于促进对AMPK的深入研究,使其成为缺血性卒中治疗的一个新靶点。     

粒细胞集落刺激因子治疗局灶性脑缺血性损伤

粒细胞集落刺激因子(G-CSF)可将造血干细胞(HSC)从骨髓中动员到外周血循环中,刺激HSC和骨髓基质细胞(MSC)向脑缺血病灶归巢,促使HSC和MSC与缺血半暗带细胞相互作用,促进神经营养因子产生.G-CSF还具有抗神经元凋亡作用,驱动神经发生.利用G-CSF动员自体HSC和MSC治疗局灶性缺血性脑损伤,可缩小脑梗死体积,促进神经功能恢复.     

传代和冻存对胎肺间充质干细胞生长及分化的影响

目的 观察传代和冻存对胎肺间充质干细胞（MSCs）生长及分化的影响.方法 以胶原酶消化法自流产胎儿肺组织中分离MSCs,在体外进行传代扩增、冻存、复苏;然后,以相差显微镜观察细胞形态学变化,以流式细胞仪检测表型变化,以神经分化诱导方案研究其向神经元样细胞分化的潜能.结果 经传代和冻存后,人胎肺MSCs的增殖能力、形态和表面标志物的表达均无明显变化,高表达MSCs特异性标志物,不表达造血和内皮细胞标志物,在适宜的神经诱导方案作用下可高效分化为神经元样细胞.结论 传代和冻存对人胎肺MSCs的形态、表型和向神经样细胞的分化潜能无明显影响,胎肺MSCs可作为细胞移植治疗神经系统疾病的备选来源.     

Notch信号通路在大鼠骨髓间充质干细胞移植后促进脑缺血区血管新生过程中的作用

目的探讨Notch1信号通路在骨髓间充质干细胞(MSCs)移植后促进脑缺血区血管新生过程中的作用。方法分离、培养SD大鼠MSCs,制作大鼠大脑中动脉栓塞(MCAO)模型,将试验分为正常组、脑缺血后MSCs移植组、脑缺血后MSCs移植+rh NF-κB组、脑缺血对照组。脑组织冰冻切片行Ⅷ因子免疫组织荧光染色检测各试验组MSCs移植1、4、7、14 d后缺血皮质区微血管数量。Western印迹检测各试验组MSCs移植1、4、7、14 d后缺血皮质区血管内皮生长因子(VEGF)165、Notch1、Hes1蛋白表达。结果缺血对照组、MSCs移植组和MSCs移植+rh NF-κB组在各时间点微血管数量及VEGF165、Notch1、Hes1蛋白表达均显著高于正常组,从第14天起开始下降,3组的微血管数量及VEGF165、Notch1、Hes1蛋白表达依次上升,差异显著(P<0.01)。结论 MSCs移植可促进缺血区新生血管的形成,并可通过激活Notch信号通路促进缺血皮质区VEGF165的表达,从而促进缺血区的血管新生。     

异基因骨髓间充质干细胞移植对胶原诱导性关节炎大鼠的免疫调节作用

目的 通过对类风湿关节炎(RA)动物模型胶原诱导性关节炎(CIA)大鼠的实验研究,观察异基因骨髓间充质干细胞(MSCs)移植对早期、晚期CIA大鼠免疫细胞和分子的免疫学作用,并探讨其在体内发挥免疫调节作用的机制.方法 采用密度梯度离心结合贴壁培养法体外分离、培养大鼠MSCs,细胞表型鉴定;建立CIA大鼠模型;MSCs移植均采用尾静脉注射,移植后第42天全部处死动物取脾,通过实时定量-聚合酶链反应(RT-PCR)测定Foxp3 mRNA的表达水平,流式细胞术测定CD4+CD25+调节性T细胞的变化.采用单因素方差分析、LSD-t检验法进行统计学分析.结果 早期、晚期CIA对照组CD4+CD25+调节性T细胞(1.6±0.6,1.4±0.6)和Foxp3 mRNA(0.88±0.20,0.91±0.12)的表达水平低于健康组和治疗组,差异有统计学意义(P＜0.05),早期治疗组CD4+CD25+调节性T细胞(5.0±0.4)比晚期治疗组(3.9±0.4)有所升高,差异有统计学意义(P＜0.05).结论 异基因MSCs移植可通过上调CIA大鼠体内CD4+CD25+调节性T细胞水平,促进Foxp3 mRNA的表达而发挥其在体内的免疫调节作用,早期治疗组的疗效优于晚期治疗组.     

间充质干细胞治疗在肝病中的应用

目的间充质干细胞(MSCs)属于中胚层的多功能干细胞,具有多向分化的潜能。在特定条件下,MSCs可分化为肝细胞、胰岛样细胞、骨细胞、软骨细胞、心肌细胞、平滑肌细胞、肌腱细胞、成纤维细胞、骨髓基质细胞、神经元、神经胶质细胞及造血系统等。因此,MSCs已成为细胞替代治疗中的主要选择细胞,广泛用于多种疾病的细胞治疗。本文就MSCs在肝脏疾病中的应用作一概述。     

间充质干细胞在糖尿病细胞疗法中的研究现状

间充质干细胞(mesenchymal stem cells,MSCs)是一类具有自我更新和多向分化潜能的细胞,在细胞替代治疗中有极其重要的作用.MSCs来源广泛,几乎所有的成体和胚胎组织中都有MSCs [1].目前研究较多的是骨髓、脂肪、滑膜、脐带血、胎肝、羊膜等来源的MSCs.MSCs最重要的特性是多能性,能分化成多种不同的细胞谱系,如骨、脂肪、软骨等间质细胞谱系,以及神经元、肝细胞和内皮细胞等内胚层和神经外胚层细胞[2-3].MSCs同样具有分化为胰岛内分泌细胞的可塑性,已经证实来源于各组织中的MSCs可以分化为有功能的胰岛素分泌细胞.本文就MSCs分化为胰岛样细胞的方法 和分化机制做一综述.     

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。     

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。     

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。     

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.