人原发性大肠癌的染色体分析

用改良的直接法分析了20例大肠癌新鲜瘤组织及4例大肠癌细胞系的细胞遗传学改变，发现瘤细胞多为异倍体，染色体众数以亚二倍体居多；核型分析发现，其杂色体数目畸变为，13号染色体增多；17号、1号和Y染色体的丢失，结构畸变最常累及1号染色体，断裂声、1q21出现率较高，其次为1p13区的断裂及末端丢失。提示1号染色体结构异常可能为原发性大肠癌特征性染色体改变之一。     

Retrospective analysis of clonality and detection of residual disease in myeloid leukemia by FISH on long-term stored bone marrow smears

Abstract Background. Fluorescence in situ hybridization (FISH) has allowed the detection of numerical chromosomal aberrations in interphase nuclei on fresh or frozen smears of leukemia.
Methods. To analyze clonality and residual disease in myeloid leukemia retrospectively, we applied FISH to bone marrow smears stored at ambient temperature for up to 9 years.
Results: When hybridization efficiency was investigated on stored control smears from patients without hematological malignancy, more than 96% of nuclei showed the expected number of signals using DNA probes specific for chromosome 7, X or Y. In combination with cell morphology, we observed much higher hybridization efficiency in blasts and granulomonocytic cells compared with lymphoid and erythroid cells. On the basis of good hybridization efficiency for old smear specimens, we applied FISH to stored bone marrow smears of myeloid leukemias, in which either loss of chromosome 7 or loss of sex chromosomes had been verified previously by conventional cytogenetics (one patient with chronic myelomonocytic leukemia (CMML) and four with acute myeloid leukemia (AML; three M2 and one M7)). As a result, the loss of chromosome was detected in blasts from all patients and was observed in mature granulocytes, except in M7. In the CMML patient and one AML (M2) patient with t(8;21), lymphoid and erythroid cells also showed the loss of chromosomes, suggesting that it should occur at stem-cell level. A high amount of residual disease was detected in the morphological remission samples in one AML (M2) patient after induction therapy. The patient eventually succumbed to relapse.
Conclusion Thus, the present FISH technique is useful to analyze the clinical significance of clonality and the residual disease in myeloid leukemia, retrospectively.     

Absence of ATM truncations in patients with severe acute radiation reactions

Purpose: Severe acute toxicity limits the effective use of radiotherapy in patients who are radiosensitive, and it is not usually possible to identify these radiohypersensitive (R-H) individuals before treatment commences. Five such R-H patients were detected over a 3-year period. We undertook this study to determine whether the severe acute radiohypersensitivity of these five individuals showed any correlation with cellular and molecular parameters known to be abnormal in radiosensitivity-related syndromes such as ataxia–telangiectasia (A-T).

Methods and Materials: Lymphoblastoid cells were isolated from fresh blood from the 5 R-H individuals who had previously demonstrated clinical R-H at least 9 months prior to sampling. Lymphoblastoid cell lines (LCLs) were established to determine the extent of postradiation chromosomal aberrations, cell cycle delay, cell proliferation, and tumor suppressor p53 protein stabilization. The polymerase chain reaction (PCR) and protein truncation (PTT) assays were used to test for the possibility of mutations in the gene mutated in A-T, termed ATM.

Results: LCLs derived from R-H subjects retained a significantly higher degree of radiation-induced chromosomal aberrations when compared to normal control LCLs. p53 stabilization by ionizing radiation appeared normal in all but one R-H subject. There was no evidence of A-T gene truncation mutations in any of the R-H subjects tested.

Conclusions: All R-H subjects in this study had their cellular radiosensitivity confirmed by the chromosomal aberration assay. Delayed p53 stabilization at 4 hours postirradiation in one R-H subject suggested that different etiologies may apply in the radiohypersensitivity investigated in this study.     

Somatic Mutations of the PTEN/MMAC1 Gene in Fifteen Japanese Endometrial Cancers: Evidence for Inactivation of Both Alleles

Loss of heterozygosity (LOH) of chromosome 10q is observed in approximately 40% of endometrial cancers. Mutations in PTEN/MMAC1 , a gene recently isolated from the 10q23 region, are responsible for two dominantly inherited neoplastic syndromes, Cowden disease and Bannayan-Zonana syndrome. Somatic mutations of this gene have also been detected in sporadic cancers of the brain, prostate and breast. To investigate the potential role of this putative tumor suppressor gene in endometrial carcinogenesis as well, we examined 46 primary endometrial cancers for LOH at the 10q23 region, and for mutations in the entire coding region and exon-intron boundaries of the PTEN/MMAC1 gene. LOH was identified in half of the 38 informative cases, and subtle somatic mutations were detected in 15 tumors (33%). Our results suggest that of the genes studied so far in endometrial carcinomas, PTEN/MMAC1 is the most commonly mutated one, and that inactivation of both copies by allelic loss and/or mutation, a pattern that defines genes as "tumor suppressors,'contributes to tumorigenesis in endometrial cancers.     

丹参对丝裂霉素C诱发小鼠生殖细胞遗传损伤的防护作用研究

本文根据动物实验模型的设计，研究了中药丹参对丝裂霉素Ｃ（ＭＭＣ）诱发雄性小鼠过生殖细胞遗传损伤的防护效应。雄性昆明小鼠随机分成８组，每组１５只，实验组分别注射高、中、低剂量丹参和ＭＭＣ，观察动物的精子畸形率、早期精细胞微核率和精原细胞染色体畸变率。结果表明，中药本身无诱变损伤作用，而对ＭＭＣ有拮抗抑制作用。提出中药丹参具有抗ＭＭＣ诱发小鼠生殖细胞遗传损伤的作用。     

LOSS OF HETEROZYGOSITY ON CHROMOSOME 13 IN SQUAMOUS CELL CARCINOMAS OF THE LARYNX

ＬＯＳＳＯＦＨＥＴＥＲＯＺＹＧＯＳＩＴＹＯＮＣＨＲＯＭＯＳＯＭＥ１３ＩＮＳＱＵＡＭＯＵＳＣＥＬＬＣＡＲＣＩＮＯＭＡＳＯＦＴＨＥＬＡＲＹＮＸＢａｉＳｕｊｕａｎ白素娟ＺｈａｎｇＸｕｅ张学ＷａｎｇＪｕｎ王筠ＳｕｎＫａｉｌａｉ孙开来ＦｅｉＳｈｅｎｇｚｈｏｎ...     

散发性结直肠癌D10S1265位点的杂合缺失分析

目的:染色体上某特定位点遗传物质的丢失是肿瘤发生中的常见现象,抑癌基因的杂合缺失是结直肠癌形成中的关键步骤之一.本实验通过对83例散发性结直肠癌中D10S1265位点杂合缺失的研究,探讨其在结直肠癌演变中的作用.方法:荧光标记的多态性微卫星引物D10S1265与83例结直肠癌的肿瘤和正常组织进行PCR反应.PCR产物在ABI Prism 377自动荧光测序仪电泳3h,以GeneScan3.1和Genotyper 2.1软件进行扫描以及杂合缺失分析.其结果与临床病理因素进行卡方检验.结果:D10S1265位点(10q24.3)的杂合缺失率是50.0%,肝转移的7例未发现LOH,无肝转移病例达58.97%(23/39,P=0.014),但与淋巴结转移无关.另外,此位点的杂合缺失与Dukes'分期显著相关(P=0.013),与其他临床病理因素无关.结论:D10S1265位点附近可能存在与散发性结直肠癌有关的抑癌基因,此基因与结直肠癌的进展和肝转移相关.     

氟吗啉诱发V79和CHL细胞基因突变和染色体畸变的研究

目的 探讨氟吗啉的致突变性。方法 首先测定氟吗啉对V79和CHL的细胞毒性，然后在非代谢活化和代谢活化条件下，进行氟吗啉诱发V79细胞HGPRT基因突变试验和CHL细胞染色体畸变试验。结果 以氟吗啉500、100、20和4μg/mL浓度处理V79细胞，处理组诱变率与阴性对照组突变率比较，差异无显著性(P≥0．05)；以500、250、125和62．5μg／mL浓度处理CHL细胞24、48h后，在非代谢活化条件下，处理组染色体畸变均小于5％，但在代谢活化条件下，处理组染色体畸变率均大于5％，而且呈剂量．反应关系，通过G-显带发现断裂集中发生于4q上，是断裂热点。结论 可以认为应用氟吗啉100～200mg／L防治植物病害不会对人类健康造成危害，但是职业人群应注意防护。     

染色体平衡易位与异常孕产

目的探讨染色体平衡易位与异常孕产的关系。方法采用外周血淋巴细胞培养和染色体G显带分析,对612对有异常孕产史的夫妇进行染色体检查。结果染色体平衡易位携带者检出率为3．3％(41／1 224),其中常染色体相互易位占58．5％(24／41),罗伯逊易位占39．0％(16／41),嵌合易位占2．4％(1／41)。9例为世界首报染色体异常核型,分别为:46,XY,t(11;12)(q13;q21);46,XX,t(3;20) (qll;q11);46,XX,t(15;16)(pll;q13);46,XY,t(2;14)(p16;q31);46,XY,t(4;10)(q25;p15);46,XX,t(3;8) (p26;q11);46,XY,t(6;16)(q15;p13);46,XX,t(18;22)(p10;q10);46,XY,t(18;22)(p10;q10)mat。总妊娠127次,早期妊娠流产率为86．6％(110／127)。结论染色体平衡易位携带者的异常孕产以早期妊娠自然流产为主要表现。