动脉粥样硬化的表观遗传学研究进展

动脉粥样硬化是环境因素与遗传因素相互作用所致的慢性炎症疾病.表观遗传修饰可能是链接环境因素与遗传因素的桥梁,深入了解表观遗传修饰如DNA甲基化、组蛋白修饰以及微小RNA对动脉粥样硬化形成和发展的影响及其作用机制,将进一步阐明动脉粥样硬化的发病机制.并且由于表观遗传修饰可逆,这可能为动脉粥样硬化的治疗提供新的策略和靶点.     

表观遗传调控在胰岛β细胞功能调控中的研究进展

表观遗传是指在DNA序列不发生改变情况下,基因表达发生可遗传性改变的现象.表观遗传在疾病发生发展中发挥重要作用,其机制十分复杂,包括DNA甲基化、组蛋白修饰和非编码RNA等.2型糖尿病是一种由遗传和环境因素共同作用而发生的复杂多基因遗传性疾病,其病因和发病机制目前尚未完全阐明.近年研究发现,表观遗传直接或间接调控胰岛β细胞的发育、分化、分泌功能以及机体对胰岛素的敏感性,参与2型糖尿病的发生和发展.对表观遗传调控的研究将为阐明2型糖尿病发病机制,及预防和治疗2型糖尿病提供新的思路和靶点.     

胰腺癌表观遗传学研究现状

表观遗传学(epigenetic)是与遗传学(genetic)相对应的学科,已经深入发展到表观遗传组学(epigenome)水平.表观遗传学研究的是基因序列不发生改变的可遗传改变,这种可遗传改变调控基因表达变化,是基因表达转录调控的另一个层面.     

支气管哮喘的表观遗传学

表观遗传的概念最早是在1942年由Waddington提出的,描述了所有细胞减数分裂和有丝分裂在表型或基因表达状态上的可遗传改变,且不借助DNA序列本身的改变[1],即表观遗传是非DNA序列差异的核遗传.表观遗传调控对哺乳动物发育期间产生细胞类型多样性起到关键作用,而且对维持不同类型细胞的基因表达谱的稳定性和完整性也很重要.     

表观遗传学与糖尿病及其并发症

表观遗传学是指在不改变基因组核苷酸序列的前提下,基因的表达水平与功能发生改变,并产生可遗传的表型.年龄、肥胖、营养和体育锻炼等环境因素与遗传因素相互作用,导致DNA甲基化,组蛋白修饰,RNA干扰等表观遗传修饰,促使免疫紊乱、炎性反应和胰岛素抵抗的发生,产生“代谢记忆”,参与糖尿病并发症的发生、发展.表观遗传机制在调控糖尿病病程中起了重要作用,其可逆转的特性为临床治疗和预防糖尿病并发症提供了新的思路.     

表观遗传学在溃疡性结肠炎中的研究进展

溃疡性结肠炎(ulcerative colitis,UC)是一种慢性非特异性疾病,病情迁延反复,有癌变的风险.目前UC的具体发病机制与发病原因尚不明确.研究表明,表观遗传修饰可介导UC的易感性基因与机体内、外环境间的相互影响,在UC的始发及其疾病持续发展的过程中起重要的作用.表观遗传修饰调控相关基因表达与UC患者的结肠黏膜免疫和防御密切相关.因此,本文对可能影响UC发病的表观遗传学机制进行综述,探讨表观遗传修饰在UC发病中的作用.     

糖尿病大血管病变的表观遗传学标志物

表观遗传学是指在不改变核苷酸序列的情况下,基因的表达活性发生了可遗传的变化,它包括DNA甲基化、组蛋白修饰、miRNA等.表观遗传学在糖尿病大血管病变的发生、发展过程发挥了重要的作用.近年来研究发现了一些反映糖尿病大血管病变的表观遗传学标志物,包括LINE-1甲基化、Alu甲基化、DDAH2启动子甲基化;Sirt1与SET7等组蛋白修饰相关酶;miRNA-126、miRNA-21、miRNA-125b等.随着表观遗传改变检测手段的改进,表观遗传学标志物有可能成为糖尿病大血管病变新的诊断手段.     

早期发育营养与成年期糖代谢异常的表观遗传学机制

尽管人们普遍认为基因与生活方式是糖尿病风险增加的主要因素,但基因改变只能部分解释糖尿病患病风险增加的原因.早期发育环境（营养状况）能显著影响成年期发生糖尿病的风险.表观遗传学与糖尿病、代谢综合征、癌症等慢性病的发病关系密切,由于表观遗传可以受到环境的刺激而发生变化,而改变的表观遗传特性可在细胞分裂中得以保持并存在,因此,表观遗传很可能是早期发育环境异常与导致成年期糖代谢紊乱这一现象的重要分子基础.另外越来越多的动物模型和大型临床研究数据显示表观遗传学机制在成年期糖代谢异常的发生发展的过程中起着十分关键的作用[1].本文将简要介绍如下.     

动脉粥样硬化的表观遗传调控

表观遗传调控指的是在DNA序列不变的情况下基因表达发生的可遗传性改变。目前,已知的表观遗传调控的主要机制包括DNA甲基化、组蛋白修饰和非编码RNA。大量研究证实,在心血管疾病、肿瘤和自身免疫性疾病等方面表观遗传调控发挥着重要作用。近年来,越来越多的研究表明,表观遗传调控在动脉粥样硬化的疾病病程中发挥着重要作用。本文将围绕DNA甲基化、组蛋白修饰和非编码RNA这三种主要的表观遗传调控对血管平滑肌细胞的调节来探讨表观遗传调控在动脉粥样硬化进程中的重要作用。     

心血管疾病表观遗传机制研究

本文阐述了心血管疾病表观遗传机制研究的最新进展,包括与动脉粥样硬化及外环境变化引起的血管平滑肌细胞和心肌细胞表型可塑性改变有关的DNA甲基化、组蛋白修饰和染色体重塑等表观遗传变化,以及其应用于心血管疾病治疗的前景.     

Colon carcinoid tumors

PURPOSE: The aim of our investigation was to evaluate the clinical presentation of patients with carcinoid tumors of the colon and to estimate the survival and potential prognostic factors of this tumor type. METHODS: A population-based study was performed using data from the Alberta Cancer Registry between 1964 and 1988 (inclusive). The clinical records and the pathologic material of eligible patients were reviewed. Survival was estimated both as crude survival and with the Kaplan-Meier method. RESULTS: During the 25-year study period (1964–1988), 36 true carcinoid tumors of the colon were diagnosed in Alberta. Carcinoids of the ileocecal region and of the rectum were excluded from the study. The average age at time of diagnosis was 68.4 years; there were 20 males and 16 females. Symptoms (abdominal pain, diarrhea, weakness, anorexia) occurred late in the course of the disease: 64 percent of the lesions were in Dukes D stage and 22 percent were Dukes C at diagnosis. Only one patient presented with a malignant carcinoid syndrome. Lesions occurred most frequently in the cecum (39 percent), followed by transverse and sigmoid colon. Most of the patients were managed surgically. The perioperative mortality rate was with 22 percent, which is quite high. The average size of the lesions was 5.8 (range, 2–10) cm, and most tumors (31/36) had invaded the pericolic fat. The most common immunohistochemical pattern was argentaffin/argyrophil negative and neuron-specific enolase positive. Two-year and five-year actuarial (Kaplan-Meier) survival was 34 percent and 26 percent, respectively. Survival for carcinoids of the colon was significantly lower compared with carcinoids of the rectum or appendix, and with colon adenocarcinomas. Size of the tumor and tumor invasion into the muscularis propria—the two major histopathologic prognostic factors for carcinoids of the gastrointestinal tract—were not found to influence survival significantly. Rather, tumor stage, histologic pattern, tumor differentiation, nuclear grade, and mitotic rate were found to significantly influence the survival rate. CONCLUSION: Carcinoid tumors of the colon are extremely rare tumors, diagnosed late in the course of the disease, and they carry a bad prognosis. Prognostic factors are tumor stage, histologic pattern, differentiation, nuclear grade, and mitotic rate of the tumor.Presented in part at the meetings of the International Society of University Colon and Rectal Surgeons, Crete, Greece, October 25 to 29, 1992, and the Royal College of Physicians and Surgeons, Quebec, Quebec, Canada, September 19 to 23, 1991.     

Étiologies et orientation diagnostique devant un flush

The flush is a transient and recurrent erythema of the upper region of the body, due to a sudden arterial dilatation. First, physicians should confirm the flush and ascertain the location and timing of skin manifestations. The rapid onset and location of the skin rash to the face and anterior chest are the main characteristics of flush. In most of the cases, the flush is emotional, but this should remain a diagnosis of exclusion, as flush may be the presenting manifestation of many systemic or neoplastic disorders. Therefore, a comprehensive diagnostic work-up is necessary, including clinical, biological, and imaging testing. Neoplastic and endocrine causes of flush include VIPoma, carcinoid syndrome, medullary thyroid cancer, mastocytosis, renal cell carcinoma, and pheochromocytoma. Mast cell activation syndrome has been recently described, but it remains a diagnosis of exclusion. This review will first present the different causes of flush, and then will propose a diagnostic algorithm for the physician.     

Experimental Analysis of Steel Circular Hollow Section under Bending Loads: Comprehensive Study of Mechanical Performance

The present study aimed at evaluating the mechanical performance under bending loads of circular hollow sections of steel. Different bending tests have been carried out by applying two-point loads, to determine and examine the effects of the diameter, the thickness of the section, and the span of the beam on the performance of the steel tube. The effects of square opening and variation in the number of openings on the performance of these sections have also been examined. Ten samples of hollow circular beams of varying thickness (2 mm, 3 mm, and 6 mm), varying diameter (76.2 mm, 101.6 mm, and 219 mm), and varying span (1000 mm, 1500 mm, and 2000 mm) were fabricated and tested for pre-failure and post-failure stages. The dimensions of the reference specimen considered were 3 mm in thickness, 101.6 mm in diameter, and 1500 mm in span. The results have shown that on increasing the section thickness by 200%, ductility and bearing strength were enhanced by 58.04% and 81.75%, respectively. Meanwhile, decreasing the section thickness by 67%, ductility and bearing strength were reduced by 64.86% and 38.87%, respectively. Moreover, on increasing the specimen diameter and on decreasing span, a significant increase in bearing strength and stiffness was observed; however, ductility was reduced. Meanwhile, on increasing the span of the specimen, all the parameters observed, i.e., bearing strength, stiffness, and ductility, decreased. On observing the ultimate strength of each specimen with square opening, the ultimate strength was reduced by 17.88%, 19.71%, and 14.23% for one, two-, and three-square openings, respectively. Moreover, the ductility was significantly reduced by 72.40%, 67.71%, and 60.88% for one, two-, and three-square openings/apertures, respectively, and led to the sudden failure of these specimens. The local buckling failure dominated for specimens having a D/t ratio more than 50 and showed very negligible levels of ovalization of the cross-section. Local buckling failure was observed to be prevented after providing the circular rings in the specimen, since bearing strength increased compared with the specimen without rings.     

武汉市血吸虫病控制达标考核结果评价

目的考核2007年武汉市血吸虫病控制达标情况。方法按照血吸虫病控制和消灭的国家标准,对武汉市洪山、蔡甸、汉南、黄陂、江夏、东西湖和江岸等7个区开展人畜查病和螺情调查。结果20042006年全市居民血吸虫感染率分别为3.06%、0.93%和0.56%,急性血吸虫病病人数分别为14、10和4例;耕牛感染率分别为0.88%、1.39%和0.67%;有螺面积分别为1 351.301、1 343.916和1 341.829万^m2。2007年,洪山、蔡甸、汉南、黄陂和江夏等5个疫情控制考核区居民血吸虫感染率0.67%,耕牛感染率0.69%。东西湖和江岸2个传播控制考核区居民血检阳性率分别为3.47%和1.71%;粪检未见阳性病人和耕牛;螺点调查未见感染性钉螺。结论2004年以来武汉市血吸虫病疫情呈逐年下降趋势,洪山、蔡甸、汉南、黄陂和江夏等5个区达到血吸虫病疫情控制标准,东西湖和江岸2个区达到血吸虫病传播控制标准。     

输入性曼氏血吸虫病监测与防控对策专家共识

我国于20世纪80年代发现曼氏血吸虫中间宿主藁杆双脐螺进入广东深圳地区，目前已在深圳定殖并扩散至东莞、惠州等地区。鉴于输入性曼氏血吸虫病病例在我国时有报道，我国已经面临输入性曼氏血吸虫病在中国大陆传播的风险。随着我国进一步深化对外开放，特别是“一带一路”倡议的深入实施，曼氏血吸虫病在中国大陆的传播风险将逐渐增大。为防止曼氏血吸虫在我国形成完整生活史并造成疾病传播，提升对曼氏血吸虫病的认识、加强提前防控的意识以及尽早发现、报告、处置输入性曼氏血吸虫病病例或病原携带者尤为重要。国内多位传染病和寄生虫病防控专家就输入性曼氏血吸虫病监测与防控对策达成共识，旨在提升我国疾病预防控制机构和医疗机构关于输入性曼氏血吸虫病诊疗和防控意识与能力、降低甚至消除输入性曼氏血吸虫病在我国传播的风险，从根本上保障我国居民健康。     

Carbon Nanofibers and Their Composites: A Review of Synthesizing,Properties and Applications

Carbon nanofiber (CNF), as one of the most important members of carbon fibers, has been investigated in both fundamental scientific research and practical applications. CNF composites are able to be applied as promising materials in many fields, such as electrical devices, electrode materials for batteries and supercapacitors and as sensors. In these applications, the electrical conductivity is always the first priority need to be considered. In fact, the electrical property of CNF composites largely counts on the dispersion and percolation status of CNFs in matrix materials. In this review, the electrical transport phenomenon of CNF composites is systematically summarized based on percolation theory. The effects of the aspect ratio, percolation backbone structure and fractal characteristics of CNFs and the non-universality of the percolation critical exponents on the electrical properties are systematically reviewed. Apart from the electrical property, the thermal conductivity and mechanical properties of CNF composites are briefly reviewed, as well. In addition, the preparation methods of CNFs, including catalytic chemical vapor deposition growth and electrospinning, and the preparation methods of CNF composites, including the melt mixing and solution process, are briefly introduced. Finally, their applications as sensors and electrode materials are described in this review article.     

Abdominal aortic aneurysms: Distribution of elastin,collagen I and III,and intermediate filament proteins desmin and vimentin—A comparison of familial and nonfamilial aneurysms

Summary The aortic walls of patients with abdominal aortic aneurysms (AAA) and of healthy controls were examined for elastin, collagen I and III, and the intermediate filament proteins desmin and vimentin by immunohistochemical, enzyme histochemical, and routine histological techniques. The morphology of the aneurysmatic walls varied considerably from case to case, but many pathological changes were seen in all cases, e.g., extensive atherosclerotic plaques in the intima, prominent alterations in amount and organization of the elastic lamellae in the media, and an increase of connective tissue. Both collagen I and III were present in all the aneurysmatic walls. The smooth muscle cells in all the aortic walls showed a marked heterogeneity with respect to the morphological appearance, the enzyme histochemical features, and the content of desmin and vimentin. Vimentin occurred in some intimal, medial muscle, and adventitial cells of both the controls and the AAA patients. Desmin occurred in some of the intimal, medial, and adventitial muscle cells of both the controls and the AAA patients. All the cells with desmin in the intima and media also contained vimentin. Thus, smooth muscle cells in the walls of both the normal human abdominal aorta and aneurysms contained either vimentin, desmin, or both. This variability may be explained by the presence of different phenotypes of smooth muscle cells and could be of significance for the development of atherosclerosis and aneurysms. Of special interest was the finding that 5 of the 24 AAA patients studied had blood relatives with the same disease, suggesting a hereditary influence. However, no systematic differences between the morphological appearance of the aneurysmatic walls in familial and nonfamilial AAA could be detected.     

Cinedefecography and electromyography in the diagnosis of nonrelaxing puborectalis syndrome

A prospective study was undertaken to assess the correlation between electromyography (EMG) and cinedefecography (CD) for the diagnosis of nonrelaxing puborectalis syndrome (NRPR). Clinical criteria for NRPR included straining, incomplete evacuation, tenesmus, and the need for enemas, suppositories, or digitation. EMG criteria included failure to achieve a significant decrease in electrical activity of the puborectalis (PR) during attempted evacuation. CD criteria included either paradoxical contraction or failure of relaxation of the PR along with incomplete evacuation. In addition, other etiologies for incomplete evacuation, such as rectoanal intussusception or nonemptying rectocele, were excluded by proctoscopy and defecography in all cases. One hundred twelve patients with constipation, 81 females and 31 males, with a mean age of 59 (range, 12–83) years were studied by routine office evaluation, CD, and EMG. Forty-two patients (37 percent) had evidence of NRPR on CD (rectal emptying: none, 24; incomplete, 18). Twenty-eight of these patients (67 percent) also had evidence of NRPR on EMG. EMG findings of NRPR were present in 12 of 70 patients (17 percent) with normal rectal emptying. Conversely, 14 of 72 patients (19 percent) with normal PR relaxation on EMG had an NRPR pattern on CD. The sensitivity and specificity for the EMG diagnosis of NRPR were 67 percent and 83 percent, and the positive and negative predictive values were 70 percent and 80 percent, respectively. Conversely, if EMG is considered as the ideal test for the diagnosis of NRPR, CD had a sensitivity of 70 percent, a specificity of 80 percent, and positive and negative predictive values of 66 percent and 82 percent, respectively. In summary, sensitivity, specificity, and predictive values of EMG and CD are suboptimal. Therefore, a combination of these two tests is suggested for the diagnosis of NRPR.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, San Francisco, California, June 7 to 12, 1992.Dr. Ger was a visiting colorectal surgeon from the Section of Colon and Rectal Surgery, Department of Surgery, National Defense Medical Center and Tri-Service General Hospital, Taipei, Taiwan, R.O.C.     

Hyaluronic-Acid-Based Organic-Inorganic Composites for Biomedical Applications

Applications of natural hyaluronic acid (HYH) for the fabrication of organic-inorganic composites for biomedical applications are described. Such composites combine unique functional properties of HYH with functional properties of hydroxyapatite, various bioceramics, bioglass, biocements, metal nanoparticles, and quantum dots. Functional properties of advanced composite gels, scaffold materials, cements, particles, films, and coatings are described. Benefiting from the synergy of properties of HYH and inorganic components, advanced composites provide a platform for the development of new drug delivery materials. Many advanced properties of composites are attributed to the ability of HYH to promote biomineralization. Properties of HYH are a key factor for the development of colloidal and electrochemical methods for the fabrication of films and protective coatings for surface modification of biomedical implants and the development of advanced biosensors. Overcoming limitations of traditional materials, HYH is used as a biocompatible capping, dispersing, and structure-directing agent for the synthesis of functional inorganic materials and composites. Gel-forming properties of HYH enable a facile and straightforward approach to the fabrication of antimicrobial materials in different forms. Of particular interest are applications of HYH for the fabrication of biosensors. This review summarizes manufacturing strategies and mechanisms and outlines future trends in the development of functional biocomposites.     

Infecciones relacionadas con el uso de los catéteres vasculares

Venous catheter-related infections are a problem of particular importance, due to their frequency, morbidity and mortality, and because they are potentially preventable clinical processes. At present, the majority of hospitalized patients and a considerable number of outpatients are carriers of these devices. There has been a remarkable growth of knowledge of the epidemiology of these infections, the most appropriate methodology for diagnosis, the therapeutic and, in particular, the preventive strategies. Multimodal strategies, including educational programs directed at staff and a bundle of simple measures for implementation, applied to high-risk patients have demonstrated great effectiveness for their prevention. In this review the epidemiology, the diagnosis, and the therapeutic and preventive aspects of these infections are updated.