Effect of single-stranded breaks on ultrastructural organization and cytochemistry of tumor cell chromatin

Laboratory of Chemistry of the Cancer Cell, Latvian Research Institute of Experimental and Clinical Medicine, Ministry of Health of the Latvian SSR, Riga. (Presented by Academician of the Academy of Medical Sciences of the USSR I. B. Zbarskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 106, No. 11, pp. 591–593, November, 1988.     

Assessment of oxidative DNA damage in the oxyR-deficient SOS chromotest strain Escherichia coli PQ300.

The SOS chromotest is a simple short-term genotoxicity assay measuring the induction of gene sfiA in Escherichia coli K-12. The recent availability of SOS tester strains with additional mutations in DNA repair or protection systems allows testing of DNA damaging compounds for genotoxic specificity. E. coli PQ300 differs from the standard SOS tester strain PQ37 in that it contains an additional mutation in gene oxyR that renders it more sensitive to oxidative genotoxins. The generation of reactive oxygen intermediates (ROI) by hydroperoxides (H2O2, t-butyl hydroperoxide, cumene hydroperoxide), gamma-radiation, glucose oxidase, and xanthine oxidase resulted in a more vigorous SOS response in strain PQ300 compared to strain PQ37. PQ300 was also more sensitive than PQ37 for the detection of reducing agents such as ascorbic acid, cysteine, and glutathione, which also alter the redox status of the bacterial cells. However, intercalating agents (adriamycin, bleomycin, and mitomycin C) and the UV- and radiomimetic compound 4-nitroquinoline-1-oxide whose DNA damaging potential are known also to involve ROI did not show significant differences between strains PQ37 and PQ300. It is concluded that the oxyR-deficient strain PQ300 is useful for detecting certain classes of genotoxins that change the oxidative/antioxidative balance of tester bacteria in the SOS chromotest.     

Quantitative DNA measurement by flow cytometry and image analysis of human nonseminomatous germ cell testicular tumors

Current clinical staging, which includes the use of serum tumor markers and imaging techniques, fails to identify the 30–40% of clinical stage I (CS I) nonseminomatous germ cell testicular tumor (NSGCT) patients who have occult metastatic disease. Therefore, there is a real clinical need to evaluate new biological parameters of the primary tumor that might be useful as predictors of occult metastatic disease. This study was undertaken to compare quantitative DNA measurements by flow cytometry and image analysis in CS I NSGCT, and to analyze the relevance of these parameters for predicting occult lymph node involvement. Different blocks of formalin-fixed, paraffin-embedded NSGCTs of 62 CS I patients who underwent retroperitoneal lymph node dissection between 1985 and 1989 were prepared according to the Hedley technique, and analyzed by quantitative cytometry. Thirty-six (58.1%) patients had histologically proven lymph node involvement (pathological stage II), whereas 26 (41.9%) patients (pathological stage I) had neither lymph node metastases according to retroperitoneal lymph node dissection (RPLND) specimens nor tumor recurrence during follow-up. Concordant results were found in 76.5% of the samples by both cytometric techniques. For flow cytometry, the percentages of aneuploid cells in the S- and the G2M+S-phase were the most robust predictive parameters for lymph node involvement, whereas for image analysis the 5c exceeding rate (5cER) had the most predictive significance. Based on the experience obtained in this study, both cytometric techniques provide additional information on tumor aggressiveness that might be useful in therapeutic selection of early stage NSGCT patients for either RPLND or surveillance only.     

乳腺囊性增生病癌变过程中部分因素变化的意义

检测乳腺囊性增生病（ＦＣＤ）经不典型增生到癌变部分因素的变化。结果提示：从因明显ＦＣＤ症状活检至癌变为２～１０年；从Ⅱ级以上不典型增生到临床癌变需２～７年；癌变率为３．１％。ＦＣＤ患者存在性激素分泌调控失常，血浆雌激素和催乳素含量增加，导致上皮细胞增生。乳腺一般性增生细胞的ＤＮＡ含量和超微结构与正常乳腺上皮细胞相似；无肿瘤相关抗原及异常基因产物表达。而发生在一般性增生基础上的不典型增生则呈现细胞基因物质ＤＮＡ含量增加，部分为超４Ｃ的多倍体细胞；同时出现细胞膜和细胞核超微结构异常；雌激素受体含量增加，对性激素的依赖性和敏感性增强；部分不典型增生细胞出现胚胎性肿瘤相关抗原和异常基因产物表达。随不典型增生程度加重至乳腺癌，上述诸因素的变化趋势具有明显规律性。提示ＦＣＤ上皮细胞从一般性增生经不典型增生至乳腺癌为细胞生物学连续逐渐变化的过程。部分不典型增生细胞中具有癌倾向的细胞生物学行为异常和表型变化与乳腺癌发生密切相关。细胞核ＤＮＡ含量等异常变化及程度可作为乳腺癌前病变发展程度的客观标志     

精神分裂症患者外周血淋巴细胞姊妹染色单体交换的初步观察

检测了18例精神分裂症患者和25例健康人的SCE频率,结果提示患者组SCE频率显著高于对照组,与年龄、性别、病程、临床类型、有无遗传家族史无明显相关。研究提示SCE频率增高似与疾病本身有关。     

测定血液脱氧核糖核酸方法的探讨

本文探讨６种测定ＤＮＡ的方法。以吲哚反应一醋酸异成酯抽提的方法最好，比较稳定而灵敏，一般实验室条件就可进行，测定仅需０．１ｍｌ血液。     

单细胞凝胶电泳技术在生殖细胞DNA损伤检测中的应用

单细胞凝胶电泳技术(SCGE)是一种快速检测单个细胞DNA损伤的实验技术,在生殖细胞DNA损伤的检测中广泛应用。本综述系统介绍了SCGE在睾丸生精细胞、支持细胞、间质细胞、卵巢细胞以及卵母细胞等生殖细胞DNA损伤检测中的应用现状,并对SCGE在生殖毒性检测中的发展提出了展望。     

Observations on two members of the Swedish family with congenital dyserythropoietic anaemia,type III

Abstract: Two affected individuals of the Swedish family with CDA, type III, in which the disease is transmitted as an autosomal dominant character, were studied. Both cases displayed features hitherto undescribed in this family but described in patients with CDA, type III, in whom the inheritance may have been as an autosomal recessive character. Such features were: (a) haemosiderinuria, (b) grossly disorganised erythroblast nuclei, (c) differences in the ultrastructural appearances of individual nuclei within the same multinucleate erythroblast and (d) intraerythroblastic inclusions resembling precipitated globin chains. In both cases the giant mononucleate erythroblasts and the multinucleate erythroblasts had total DNA contents up to 28c (1c = haploid DNA content) and 48c respectively, and some DNA synthesising bi- and multinucleate erythroblasts contained one or more nuclei which were unlabelled with ³H-thymidine. These findings are similar to those in patients with the autosomal recessive type of disease. Thus no major phenotypic differences are yet apparent between cases of CDA, type III, with different patterns of inheritance. Analysis of the surface erythrocyte proteins of the 2 Swedish CDA, type III, patients with monoclonal antibodies recognising Band 3, glycophorins A, B, C and D, Rh, CD44, CD47, CD55, CD58, CD59, Lutheran, Kell, LW and acetylcholinesterase did not reveal any gross abnormality of expression of these proteins. A slightly altered expression of blood group antigens A and H was revealed by the lectins Dolichos biflorus and Ulex europaeus and the Mr of Band 3 as judged by SDS polyacrylamide gel electrophoresis was also slightly reduced, suggesting that there may be minor alterations in the degree of N-glycosylation of some red cell membrane constituents.