MicroRNA与DNA甲基化相互调节机制在肝细胞癌中的研究进展

肝细胞癌是原发性肝癌的主要类型,也是人类恶性程度较高的肿瘤之一,其发病机制至今尚未完全阐明.表观遗传学机制在肿瘤的发生、发展中起重要作用,DNA甲基化和微小RNA (microRNA,miRNA)的调控机制属于表观遗传学的研究范畴.研究表明,DNA甲基化及miRNA在肝细胞癌的形成中分别或协同发挥着重要作用,miRNA是一类在转录后水平调节基因表达的非编码短链RNA.研究表明,DNA甲基化和组蛋白修饰不仅可以调节蛋白编码基因的表达,而且可以调节miRNA的表达.在肝细胞癌中,一些异常表达的miRNAs(如miR-125b、miR-1-1、miR-124、miR-203和miR-191)是通过表观遗传学机制调控的.另外,在肝细胞癌中还发现了一类miRNAs通过调控表观遗传学通路中关键分子来改变整个基因组的表观遗传学状态.本文就DNA甲基化和miRNA之间复杂的相互调节机制在肝细胞癌发生和发展中的研究进展进行综述.     

B细胞淋巴瘤表观遗传学研究进展

表观遗传学是功能基因组学的重要组成部分,是研究DNA序列不发生变化但基因表达发生遗传性改变的一门遗传学分支学科,主要包括DNA甲基化、组蛋白修饰、染色体重塑和微小RNA(miRNA)等基因表达调节机制.表观遗传学调控机制在B细胞淋巴瘤的发展中具有重要作用,有研究表明在B细胞淋巴瘤中常见表观遗传学模式的不稳定性和分子突变.文章从DNA甲基化、组蛋白修饰、miRNA等方面对B细胞淋巴瘤的发生、发展、治疗及预后进行综述.     

表观遗传学与结直肠癌的关系研究进展

表观遗传学(Epigenetics)与遗传学(Genetics)是相对应的概念。遗传学改变是指基于基因序列改变所致基因表达水平变化,如基因突变、基因杂合丢失和微卫星不稳定等;而表观遗传学改变则是指基于非基因序列改变所致基因表达水平变化,如DNA甲基化、组蛋白修饰和基因组印迹等。研究表明遗传和表观遗传异常都参与肿瘤的发生。结直肠癌是常见的恶性肿瘤之一,全世界每年大约有120万新发病例,同时至少60万患者死亡[1]。结直肠癌有着极为复杂的发生发展机制,传统观点认为肿瘤的主要机制是由于致癌因素造成DNA序列变异而导致细胞生长、分化失控。近年来,随着研究的深入,发现DNA序列以外的调控机制异常在肿瘤的发生、发展过程中更为普遍[2],这种不依赖于DNA序列变化的可遗传的调控机制即为表观遗传学机制,这也为结直肠癌的诊断和治疗开辟了新的途径。1表观遗传学分子机制与结直肠癌1.1DNA甲基化与结直肠癌DNA甲基化是指由DNA甲基转移酶(DN-MT)催化,把S-腺苷甲硫氨酸(SAM)的甲基转移到胞嘧啶5位碳原子上,生成5-甲基胞嘧啶(5-mC)引起基因表达异常的过程。DNA甲基化包括整体基因组的低甲基化和启动子特殊区域CpG岛...     

肿瘤的表观遗传学研究进展

表观遗传学是不涉及基因序列变化而发生的基因表达水平的改变,并且这种变化是可逆的。表观遗传学主要包括 DNA 甲基化、组蛋白修饰、非编码 RNA 调控、染色质重塑。随着对表观遗传学的深入研究,其在恶性肿瘤发生发展中的作用已得到认可。     

肺癌表观遗传学的研究进展

目的:总结目前肺癌表观遗传学的研究进展,指导肺癌的早期诊断、治疗及预后。方法:应用NCBI的Pubmed和CHKD期刊全文数据库检索系统,以"肺癌、表观遗传学"等为关键词,检索2004-01-2009-12相关文献24篇。纳入标准:1)DNA甲基化。2)组蛋白修饰。3)非编码RNA调控,包括RNA干扰及MicroRNA。根据纳入标准分析24篇文献。结果:表观遗传学改变,如DNA的甲基化、组蛋白修饰及非编码RNA调控等在肺癌的发生、发展中起着重要作用,可以指导肺癌的早期诊断、治疗及预后。结论:对肺癌表观遗传学的深入研究,将为肺癌的治疗提供新的策略和方法。     

DNA甲基化调控在免疫学研究中的进展

表观遗传学是研究基因序列不发生改变的情况下,基因表达发生了可以遗传的改变的一门学科。DNA甲基化是表观遗传学中进化上比较保守、相对比较稳定的一种表观修饰。DNA甲基化,特别是CpG岛的高甲基化,通常能够介导基因表达的稳定沉默。研究表明,DNA甲基化参与调控免疫系统的分化发育,DNA甲基化的异常也是包括肿瘤在内的众多免疫相关疾病发生、发展的关键致病因素。表观遗传学与免疫学的碰撞也为理解免疫学现象的分子调控机制提供了崭新的视角。本文将对近年来DNA甲基化调控在免疫学中的进展作一综述。     

表观遗传学在结直肠癌中的应用进展

结直肠癌（CRC）的发生、发展伴随着许多基因的表达变化,但其具体调控机制至今仍未完全阐明。近年来对CRC表观遗传学尤其是微小RNA（miRNA）、异常DNA甲基化及组蛋白修饰状态等方面的研究受到广泛关注。研究证实,CRC进展过程中均存在异常的甲基化基因和miRNA的表达变化。与癌症基因组的基因突变一样,这类遗传学的分子改变在CRC中扮演着重要角色。表观遗传学的特异性改变可作为CRC诊断、治疗和预后的临床生物学标记物,对表观遗传学进行深入研究对CRC的防治具有重要指导意义。     

白血病微小残留病的检测及相关治疗中DNA甲基化的研究进展

DNA甲基化异常在恶性肿瘤中是一种最常见的表观遗传学改变,它在基因表达调控、基因组稳定性中起着重要作用,与白血病的发生、发展密切相关。肿瘤相关基因甲基化状态的分析可作为一种生物标志物用于白血病微小残留病的检测及复发风险的评估。因此,诱导抑癌基因去甲基化在抗肿瘤药物研究中具有重要意义。本文就近年来在DNA甲基化与白血病发生的关系及白血病去甲基化相关治疗的研究进展作一综述。     

DNA甲基化在肺癌中的研究进展

肺癌是严重威胁人类生命健康的恶性肿瘤之一。DNA甲基化作为表观遗传学的主要组成部分,其在细胞增殖、凋亡、DNA修复、肿瘤侵袭和转移等生物过程中起着重要作用。大量研究证明,DNA甲基化在肺癌的发展中扮演着重要的角色,本文就近年来DNA甲基化在肺癌中的发病机制、诊断、治疗及预后的研究进展作一综述。     

DNA甲基化与肿瘤发生发展机制研究进展

表观遗传学在肿瘤发生发展中具有重要的作用,其中DNA甲基化被认为是肿瘤形成的重要机制之一.在肿瘤形成过程中,DNA甲基化的模式发生了巨大变化,包括整个基因组的去甲基化和部分区域高度甲基化两种现象.抑癌基因通常因高度甲基化而失活,这种基因沉默调控与体细胞突变共同促进了肿瘤的发展.目前对基因表达调控的研究加深了对基因沉默机制的理解,也为肿瘤发生机制研究及其早期诊断和潜在的治疗开辟新的方向.     

Dermatomycosis in Goats in India

Summary: In an extensive survey involving 2176 goats 1.56% of goats manifested clinical lesions of ringworm infection. Animals below the age of 6 months were affected most (4.20%). The incidence of infection was higher during the winter months. T. verrucosum, T. mentagrophytes and M. gypseum were isolated from the skin scrapings of 12, 4, and 2 goats respectively. It is suggested that the infected animals could be a source of disease to human population in which the zoophilic dermatophyte invasion is characterized by severe inflammatory lesions of the skin. The zoonotic importance of different dermatophytes is stressed.
Zusammenfassung: In einer ausgedehnten Untersuchung an 2176 Ziegen wurden bei 1,56% klinische Zeichen einer Hautmykose festgestellt. Tiere, die jühger als 6 Monate alt waren, zeigten mit 4,20% am häfigsten Krankheitssymptome. In den Wintermonaten war die Erkrankungshäufigkeit am gröBten. T. vermcosum, T. mentagrophytes and M. gypseum wurden jeweils von 12,4 bzw. 2 Ziegen isoliert. Die inflzierten Tiere köinnen eine Infektionsquelle für die menschliche Bevölkerung darstellen und dort Mykosen mit stark entzündlichen Veränderungen auslösen. Die Bedeutung verschiedener Dermatophyten als Erreger von Zoonosen wird hervorgehoben.     

Trends in zygomycosis in children

Zygomycosis, or mucormycosis, is associated with significant morbidity and mortality in both children and adults. Studies in adults have shown an increase in the incidence of zygomycosis, particularly among haemtopoietic stem cell transplant (HSCT) recipients and patients with haematologic malignancies. There is a paucity of data on the epidemiology of zygomycosis in children. We performed a retrospective analysis to describe trends in zygomycosis between 1 January 2003 and 31 December 2010. We used the Pediatric Health Information System (PHIS) database to identify paediatric patients who were diagnosed with zygomycosis during the study period. Administrative data on diagnoses, demographics, underlying conditions and clinical experiences were collected. Summary statistics were calculated and tests for trend were conducted. We identified 156 unique patients with zygomycosis. The prevalence of zygomycosis did not significantly increase over time (P=0.284). The most common underlying condition was malignancy (58%) and over half received intensive care. Voriconazole utilisation among all hospitalised children significantly increased during the period (P=0.010). Our study demonstrates that the incidence of zygomycosis is not significantly increasing. During the time period there was a significant increase in the use of voriconazole among children.     

Increased apoptosis in cancer cells in vitro and in vivo by ceramides in transferrin-modified liposomes

Lysosomes are a promising therapeutic target for induction apoptosis in cancer cells due to lysosomal membrane permeabilization (LMP) leading to leakage of hydrolytic enzymes, especially the cathepsins, into the cytoplasm. We hypothesized that with the modification of the ceramide-loaded liposomes with transferrin (Tf), we would achieve both tumor targeting and increased delivery of lysosome-destabilizing agents, such as ceramides to lysosomes, to initiate LMP-induced apoptosis. We prepared Tf-modified (TL) and plain (PL) liposomes and loaded with short (C6)- or long (C16) N-acyl chain ceramides. Uptake, intracellular localization of liposomes, stability of the lysosomal membrane and release of cathepsin D were investigated on Hela cells by fluorescence microscopy and flow cytometry. Apoptosis was evaluated by binding of fluorescently-labeled Annexin V. Antitumor and pro-apoptotic effects of C6Cer-loaded Tf-liposomes were demonstrated in vivo in an A2780-ovarian carcinoma xenograft mouse model. TL were internalized specifically via the TfR-dependent endocytic pathway and localized within the endosome-lysosomal compartment. Ceramide-loaded Tf-liposomes significantly increased apoptosis compared with ceramide-free and ceramide-loaded non-modified liposomes. The treatment of cancer cells with TL led to increased LMP and cytoplasmic relocation of the intralysosomal cathepsin D. A strong antitumor and pro-apoptotic effect of C6Cer-loaded TL was also demonstrated in vivo in an A2780-ovarian carcinoma xenograft mouse model. The lysosomal accumulation of ceramides delivered by Tf-liposomes initiates the permeabilization of the lysosomal membranes required for the release of lysosomal cathepsins into the cytoplasm and initiation of the cancer cell apoptosis both in vitro and in vivo.     

Ringworm in animals in a farm in Assiut

Bericht über das Auftreten von Hautmykosen bei Tieren auf der Farm der Landwirtschaftlichen Fakultät der Universität Assiut. Von 70 Kälbern waren 42 pilzkrank, davon 22 durch T. mentagrophytes, 20 durch T. verrucosum. Von 180 Kühen waren 8 pilzbefalien, sämtlich durch T. mentagrophytes. Von 2 kranken Bullen wurde T. verrucosum isoliert. Auch die 3 Pferde und 2 Maultiere der Farm waren pilzinfiziert; Erreger war in diesen Fällen T. equinum. Auch ein Kalb war von T. equinum befallen. Die gleiche Pilzart wurde ferner von 3 Tierpflegern isoliert, die Pilzherde am Hals und an den Armen aufwiesen.     

Socioeconomic factors in cancer in Sweden

It is well known that certain cancers have shown clustering in socioeconomic groups, but limited data are available on recent results and time trends in such clustering. We determined standardized incidence ratios (SIR) for cancer, adjusted for age, period, region, parity and age at first childbirth among men and women in 6 socioeconomic groups based on the Swedish Family-Cancer Database. Persons had to be identified with the same socioeconomic status in the census of years 1960 and 1970, or of years 1960, 1970 and 1980; the comparison group was all people according to the same censuses. Cancers were followed from years 1970 to 1998 or from 1980 to 1998. Both increased and decreased SIRs were found, and a consistent pattern emerged, although the overall SIRs for cancer did not differ much, the lowest being for farmers (0.85) and the highest for professional men (1.07) and women (1.11). At individual sites, manual workers were at risk of tobacco-, alcohol- and occupation- and human papilloma virus-related cancers and at a decreased risk at most other cancers. Manual workers and farmers showed an excess of stomach cancer; professionals had an excess of melanoma and squamous cell skin cancer. Male and female SIRs correlated highly for manual and blue-collar workers and for professionals. The overall population-attributable fraction for selected sites was 16.7% for men and 10.9% for women and it was highest, over 50%, for lung cancer in both genders.     

Survey of changes in dietary preferences in cancer patients in China

Objective The aim of this study was to investigate the changes in dietary preferences in cancer patients in China and to determine the need for encouraging the adherence to a sensible diet among such patients.Methods A total of 468 cancer patients were interviewed using a self-designed questionnaire focusing on changes in the intake of specific foods. Data were analyzed using SPSS 16.0. Results Most patients completely avoided roosters and carp(73.1%), condiments(51.9%), and meat of aquatic species(40.4%). All other types of the specific foods were completely avoided by different subpopulations of the patients.Conclusion In addition to focusing on disease treatment, medical professionals need to help cancer patients overcome barriers associated with the customs of avoiding specific foods encompassed by the term ”fawu” and provide them with dietary guidance in order to prevent negative nutritional effects.     

Advances in cancer epidemiology in Japan

Epidemiologists in Japan have been performing calculations to estimate nationwide cancer incidence rates as well as 5‐year survival rates using population‐based cancer registry data. There have been remarkable changes in cancer incidence and/or mortality in cancers of the lung, liver and stomach, which were thought to be attributed to the changing impact of exposure to cigarette smoking, chronic hepatitis C virus infection and Helicobacter pylori infection, respectively. In systematic reviews providing evidence in risk/protective factors for cancer sites using case–control and cohort studies of the Japanese population, there were associations between cancer sites (esophagus, stomach, colo‐rectum, liver, pancreas, lung and breast) and various lifestyle factors. In the past 10 years, a hospital‐based case–control study at Aichi Cancer Center provided valuable evidence of gene‐environment interaction on the development of cancer [i.e., the effects of aldehyde dehydrogenase‐2 (ALDH2) polymorphism and heavy alcohol drinking on esophageal cancer, ALDH2 polymorphism and smoking on lung cancer, methylenetetrahydrofolate reductase polymorphism and heavy alcohol drinking on pancreatic cancer]. The database with stored DNA was also used and identified seven loci containing significant but low‐penetrance polymorphisms associated with the development of breast cancer. These findings together with established risk factors are likely to be useful to predict personalized breast cancer risk in East Asian women. In 2005, the Japan Multi‐Institution Collaborative Cohort (J‐MICC) study was launched to elucidate gene‐environment interactions as well as to confirm preclinical diagnostic biomarkers of cancer. J‐MICC, which has recruited 92,000 healthy individuals by the end of 2012, will follow the individuals until 2025.     

Foreign bodies in ENT in a teaching hospital in Eastern India

Objective

To evaluate the nature, common sites, modes of presentation of various foreign bodies (FB) in Ear, Nose and Throat (ENT).

Materials and methods

Observational retrospective study carried out at Vivekananda Institute of Medical Sciences, Ramakrishna Mission Seva Pratishthan. The study period was between Jan 2006 to Jan 2007. The information obtained from the hospital record books.

Results

Four hundred and eighty-two patients presented in the Department of Otorhinolaryngology of Vivekananda Institute of Medical Sciences, in the study period with FB in their ENT. Out of 482 pts, the commonest location of FB was to be in throat with 302 pts (62%) followed by ear with 119 pts (25%) and nose 61 pts (13%). Amongst the FB in throat the commonest was fish bone and the commonest site being tonsils. Artificial denture accounted for a significant number of 13 (4.3%). External auditory canal was the commonest site of FB lodgment in ear found in 118 patients (99.16%). Nasal FB were found in 61 patients; more common in pediatric age group (98.36%).

Conclusion

From this study we have found that FB lodgement is a very common complaint with which patients come to otolaryngologist. The commonest site of FB lodgement is in the throat. Most of the FB could be removed in emergency room (ER) with or without Local Anesthesia.     

整合素在急性白血病中的研究进展

急性白血病是一种早期造血干/祖细咆的恶性克隆性疾病.微小残留病和耐药被认为是其复发和难治的根源.近来,越来越多的证据显示白血病细胞通过与骨髓微环境中的基质细胞或细胞外基质相互作用促进其存活,并增强其对常规化疗药物的耐药.整合素是介导细胞与细胞外基质（细胞与非细胞成分）粘连的最主要黏附分子,在细胞增殖、存活等生物学过程中发挥关键作用,但作用机制尚不完全清楚.现就目前揭示的整合素及肿瘤微环境在急性白血病发生、发展中的作用进行综述.