A comparative study of using comet assay and gammaH2AX foci formation in the detection of N-methyl-N'-nitro-N-nitrosoguanidine-induced DNA damage.

Comet assay is a useful technique in the detection of DNA damages, particularly DNA strand breaks; and it has been utilized to show that a potent carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), can induce such damages. Recently, gammaH2AX foci formation has been suggested as another sensitive way to detect DNA double strand breaks (DSBs). However, there is no systematic comparison being conducted to evaluate the consistency of these two methods. Using MNNG as a model chemical, the sensitivity of neutral comet assay and gammaH2AX foci formation in detecting MNNG-induced damage was studied. It was found that at concentrations of 0.1 and 1 microg/ml, both methods can detect MNNG-induced damage in human amnion FL cells. However, at 0.1 microg/ml, comet assay revealed more percentage of cells with DNA damage than gammaH2AX fluorescence revealed. On the other hand, while gammaH2AX foci were readily formed at very early times by 10 microg/ml MNNG treatment, neutral comet assay did not detect any significant DNA damage at the same time points. In addition, 10 microg/ml MNNG induced a distinct whole nuclei staining pattern of gammaH2AX, a type of DNA damage which was not detected by neutral comet assay but could be detected by alkaline comet assay. Therefore, gammaH2AX may be used as a sensitive indicator for DNA damage.     

大肠癌手术前后血清CA199和CEA水平变化临床价值的研究

目的:研究大肠癌患者手术前后(包括根治术及姑息手术)血清CA199和CEA水平的变化.并探讨其应用价值。方法:应用全自动化学发光免疫分析法,分别测定临床确诊的50例大肠癌患者(术前和手术30 d后)及50例正常成人血清CA199与CEA含量变化。结果:50例大肠癌患者手术前后血清CA199和CEA检测显示,术前血清CA199和CEA均高于对照组(P<0.01),术后血清CEA较CA199下降快,而且大肠癌患者术前血清CA199和CEA含量较根治术30 d后有明显增加,差异有统计学意义(P<0.05)。而姑息性切除手术前后血清CA199和CEA含量变化不大(P>0.05),差异无统计学意义。结论:大肠癌患者术前血青CA199和CEA含量显著增高.而根治术后血清CA199和CEA均有较明显下降。因此,术后定期联合监测血清CA199和CEA有利于临床观察大肠癌患者病情变化,评价手术效果,预测首程化疗疗效,为判断预后、及早发现术后复发病人提供依据。     

基底动脉缝隙连接蛋白的分布

目的：探讨正常脑血管缝隙连接蛋白的分布。方法：采用RT—PCR、免疫组化方法测定多种缝隙连接蛋白在大白兔基底动脉的表达。结果：(1)RT—PCR发现大白兔基底动脉血管组织中至少存在Xx45、Cx43、Cx40和Cx37四种缝隙连接蛋白mRNA表达；(2)免疫组化证实Cx45和Cx43主要分布于血管内皮，平滑肌细胞间末见Cx45和Cx43的染色。结论：大白兔基底动脉血管组织存在丰富的缝隙连接蛋白的表达，与体内其它弹力血管相比，缝隙连接蛋白的分布模式有其特殊性。     

Demonstration of proteases in basal cell carcinomas. A histochemical study using amino acid-4-methoxy-2-naphthylamides as chromogenic substrates.

BACKGROUND. Proteases are reported to play an essential part in the proliferative, invasive, and metastasizing behavior of malignant tumors. The aim of the current study was to determine the activity and localization of proteases in basal cell carcinomas (BCC) histochemically. METHODS. Various proteases were identified histochemically in frozen sections of BCC. The following amino acid-4-methoxy-2-naphthylamides (MNA) were used as chromogenic substrates:alanine-MNA for the detection of aminopeptidase M (APM), glycyl-proline-MNA for dipeptidyl peptidase IV (DPP IV), lysyl-proline-MNA and lysyl-alanine-MNA for dipeptidyl peptidase II (DPP II), glycyl-arginine-MNA for dipeptidyl peptidase I (DPP I), and carbobenzoxy (CBZ)-arginyl-arginine-MNA for cathepsin B. RESULTS. APM activity was high in the peritumorous connective tissue, whereas the tumor epithelium and epidermis had negative results. DPP IV showed a highly positive reaction in both tumor epithelium and surrounding connective tissue. Cathepsin B and DPP I reacted strongly in the tumor epithelium but not in the peritumorous connective tissue. CONCLUSIONS. The marked activity of APM, DPP IV, DPP I, and cathepsin B may be related to the proliferation and invasive growth of BCC. The distribution of the activity of APM and DPP IV indicates dynamic interactions between the tumor epithelium and the adjacent connective tissue in the neoplastic process.     

The properties of monoclonal antibodies to HIV gag gene proteins]

Immunization of BALB/c mice with natural purified HIV antigen, fusion of spleen cells with myeloma cells and subsequent selection of hybrid clones using recombinant gag antigen of HIV gave hybridomas producing monoclonal antibodies (MCA) to HIV. The immune blotting method demonstrated that 3 clones interacted with protein p24 and 4 clones with protein p17 of HIV. Competitive EIA led to a conclusion that the resulting MCA detected at least 3 antigenic determinants in proteins, products of gag gene of HIV. The potentials of using these MCA for the detection of viral antigen in HIV-infected continuous cell lines were demonstrated.     

A case of juvenile chronic myeloid leukemia with XX/XXX mosaicism.

Cytogenetic abnormalities are rarely found in patients with juvenile chronic myelogenous leukemia (JCML). In patients with chromosomal abnormalities, chromosomes 7 and 8 are usually involved. A case of JCML with 47 XXX and a 46 XX karyotype is described and the literature is reviewed. To our knowledge, this is the first case ever to have been reported.     

Lenticulostriate arteries in aging process: an angiographic study

Histological studies describe in detail the changes of the small arteries wall with controversial results concerning lumen narrowing during the aging process. In this study, the anatomic and the angiographic parameters of the medial and lateral lenticulostriate arteries were analysed in 64 carotid angiograms. Only 20% of the total number of lenticulostriate arteries were shown on angiograms. Collateral branches were rarely visible, especially those of medial group. The course of the lenticulostriate arteries was mostly straight or moderately tortuous. No significant differences were noted in any of the measured parameters when compared with the age (p greater than 0.05). It appears that age-related changes spread over external layers of small arteries, with no lumen narrowing or filling defect.     

与铁稳态有关的生物分子

根据近几年来发表的与铁稳态有关的生物分子的研究文献 ,将这些生物分子根据其与铁的吸收、转运、储存以及对铁稳态的监控调节等方面的关系 ,对这些生物分子进行了分类。特别是对细胞膜载体、运铁蛋白受体、铁调蛋白及铁反应元件等作了较为详细地论述