Clastogenic effect of fenfluramine in mice bone marrow cells in vivo

Fenfluramine, an amphetamine derivative used in the treatment of obesity, has been evaluated in vivo in the bone marrow cells of Swiss albino mice using two cytogenetic endpoints for assessing its genotoxic and clastogenic potentials. Concentrations of 0.75, 1.5, 3.0, and 5.0 mg/kg b.w. were administered orally for the study of sister chromatid exchange frequencies and chromosome aberrations (CA). SCE frequencies showed a positive dose response; 1.5 mg/kg being the minimum effective concentration. Fen caused a prolongation of cell cycle at all concentrations. Except for the minimum therapeutic dose (0.75 mg), all other doses (1.5, 3.0, and 5.0 mg) showed a significant increase in the percentage of damaged cells over that of the vehicle control. The degree of clastogenicity was directly proportional to the dosage used and inversely related with the duration of treatment. A gradual reduction of the clastogenic potential was observed after 12 and 24 hr of exposure, indicating that the maximum effect occurs at the middle or late synthetic phase of the cell cycle. This study, probably the first detailed screening of the drug for its genotoxicity, shows that Fen is moderately clastogenic and a DNA damaging agent in vivo.     

PCR检测结核分枝杆菌DNA中不同细菌裂解方法结果观察

目的：寻找适合于临床ＰＣＲ检测结核杆菌ＤＮＡ简单、快速、有效、经济的细菌裂解方法。方法：采用１１种细菌裂解剂对相同数量的结核分枝杆菌进行裂解，裂解上清液直接用于ＰＣＲ扩增，结果：１％ＴｒｉｔｏｎＸ－１００，１％ＮＰ４０，１％Ｔｅｗｅｅｎ２０、和１％ＯＰ四种裂解剂的裂解液可直接扩增出结核分枝杆菌ＤＮＡ；ＳＤＳ，ＮａＯＨ，十二烷基肌酸钠等裂解剂的裂解液直接用于ＰＣＲ扩增均为阴性。结论：１％的Ｔｒｉｔｏｎｘ－１００，ＮＰ４０、Ｔｅｗｅｅｎ２０和乳化剂ＯＰ裂解细菌效果好，又不抑制ＰＣＲ反应，适合于作为临床ＰＣＲ检测结核杆菌的裂解剂。     

Rh phenotype prediction by DNA typing and its application to practice

The complexity of the RHD and RHCE genes, which is the greatest of all blood group systems, confounds analysis at the molecular level. RH DNA typing was introduced in 1993 and has been applied to prenatal testing. PCR-SSP analysis covering multiple polymorphisms was recently introduced for the screening and initial characterization of partial D. Our objective is to summarize the accrued knowledge relevant to the approaches to Rh phenotype prediction by DNA typing, their possible applications beyond research laboratories and their limitations. The procedures, results and problems encountered are highly detailed. It is recommended that DNA typing comprises an analysis of more than one polymorphism. We discuss future directions and propose a piecemeal approach to improve reliability and cost-efficiency of blood group genotyping that may eventually replace the prevalent serology-based techniques even for many routine tasks. Transfusion medicine is in the unique position of being able to utilize the most extensive phenotype databases available to check and develop genotyping strategies.     

食管癌高发及低发区患者DNA修复功能的研究

本文对食管癌高、低发区食管癌患者和正常人,经MNNG诱导的DNA损伤修复功能进行了研究。实验采用外周血淋巴细胞培养的方法。每组又分为对照组及MNNG诱导组。样品以~3H-TdR标记后经液闪仪计数法进行检测。结果发现,低发区正常人经MNNG诱导的DNA损伤修复功能明显高于对照组,两个地区食管癌患者修复能力均低于正常人,与地区无关。     

聚合酶链反应（PCR）对单纯疱疹病毒性脑炎的临床诊断价值

应用聚合酶链反应（ＰＣＲ）检测技术对１１８例颅内感染性疾病患者及３７例无神神经系统疾病患者脑脊液（ＣＳＦ）中的单纯疱疹病毒ＤＮＡ（ＨＳＶ－ＤＮＡ）进行了检测及分型。结果提示：“散发性脑炎”组的阳性率为３８．４６％（２０／５２），细菌、真菌性脑膜炎、其它病毒性脑炎组以及无神经系统疾病组均为阴性。作者认为：①本检测是目前单纯疹病毒性脑炎（ＨＳＥ）较为简便而准确的早期诊断方法之一；②ＨＳＶ分型检测，对病原诊断更具有全面性；③两型单纯疱疹病毒均可引起ＨＳＥ。     

Licensing and control authority batch release of influenza vaccine in Germany in accordance with EEC regulations

The epidemiological situation calls for almost yearly changes in the antigenic composition of influenza vaccine, thus necessitating fresh licensing procedures. Since the time for bringing a new vaccine onto the market should be relatively short, the following work of all parties involved must be done expeditiously: 1) WHO recommendations on new virus strains and their subsequent adaptation by the EEC (February/March); 2) Distribution of the new virus strains to the International Reference Centers for Influenza in the UK and USA (February/ March); the centers later issue reference materials for the determination of the haemagglutinin antigen concentration (April/May); 3) Production and testing of seed virus by manufacturers, as well as validation of the producer's inactivation process for the new virus strains (May/June); 4) Licensing of the vaccines by the National Control Authority (Paul-Ehrlich-Institute) (June/July); in the case of previously licensed products, the procedure is limited essentially to the approval of the detailed protocol of production and tests on the new virus strains, clinical studies not being required before licensing because of a lack of time; 5) Paul-Ehrlich-Institute's test for batch release, according to Directive 89/342/EEC, besides protocol approval, conducts material testing of the endotoxin and antigen content of each vaccine lot; the assay for the antigen quantification is especially laborious and sometimes must be repeated because of test invalidity.     

DNA flow-cytometric analysis in colorectal cancer: A comparison of metastasizing and non-metastasizing tumours

The most common cause of death in patients with colorectal cancer is metastatic liver disease. In order to identify patients at a high risk of developing hepatic secondaries from colorectal cancers, DNA content was measured in metastasizing colorectal primaries (Group I, n= 32) as well as in their subsequently resected liver secondaries and in sections of non-metastasizing colorectal cancers (Group II, n= 25). A modified interpretation system involving both a DNA index and percentage of cycling cells (those in S and G2 + M phases) was developed. DNA content was measured in paraffin-embedded sections by flow cytometry using internal controls (human peripheral blood mononuclear cells) and non-malignant tissue controls (19 patients with diverticular disease). In Group I there were significantly more tumours with both abnormal ploidy (aneuploid or abnormal tetraploid peak) and > 15% cycling cells compared with Group II (Chi-squared; P= 0.034). The combination of abnormal ploidy and > 15% cycling cells was superior to Dukes’ classification for identifying metastasizing tumours (Logistic Regression; P= 0.047). However, it was not possible to discriminate between the two groups using either DNA ploidy or the percentage of cycling cells alone. The metastasizing colorectal cancers exhibited similar DNA ploidy characteristics and had a similar percentage of cycling cells compared with their liver metastases. These results suggest that tumour DNA ploidy plus the percentage of cycling cells may predict the development of liver metastases and thus survival in patients with colorectal cancer.     

Dendritic Cells Coinjected with Tumor Cells Treated with an Anticancer Drug to Induce Tumor Rejection

Purpose: We examined whether bone marrow-derived dendritic cells (DCs) could induce antitumor immunity when a chemotherapeutic drug was added. Methods: CT26 (a murine colon cancer cell line syngeneic with BALB/c) and CT26-bearing mice were treated with mitomycin C (MMC) intraperitoneally (i.p.). Next, mice immunized with a coinjection of DCs and MMC-treated CT26 (i.p.) were given an intradermal inoculation of CT26. Finally, CT26-bearing mice were treated with MMC (i.p.) with or without DCs, given peritumorally. Results: Although the inoculated tumor was not rejected in the control mice, CT26 was rejected in 50% of the mice injected with MMC alone. Apoptosis was observed in the MMC-treated CT26 cells in vitro and in vivo. Immunization with DCs and apoptotic CT26 cells, but not with apoptotic CT26 alone, gave protection against tumor challenge in 7 of 13 mice. A significantly higher level of cytotoxic T-cell activity and interferon-γ production was seen in the protected mice. When MMC (i.p.) treatment was followed by peritumoral DC injection in the CT26-bearing mice, remarkable therapeutic effects were observed. Conclusion: DCs can collaborate with chemotherapy-induced apoptotic tumor cells and elicit improved antitumor immunity, probably through the acquisition of tumor-associated antigens from apoptotic tumor cells. Received: January 7, 2002 / Accepted: September 3, 2002 Acknowledgments. We thank Dr. Kazuo Kinoshita for his useful advice on using flow cytometry. This research was partly supported by the Ministry of Education, Culture, Sports, Science and Technology (No. 11671160). Reprint requests to: S. Yamasaki