Acute monocytic leukemia chromosome studies

Cytogenetic studies have been performed on 34 acute monocytic leukemia (M5) patients, 24 of the a type and 10 of the b type. No chromosomal abnormalities were found in 12 cases, in spite of the fact that the mitoses concerned monocytes. Different chromosomal aberrations were present in the other cases. In 12 of them, an abnormality of the chromosome 11 long arm was observed (mainly in the poorly differentiated type of M5), on bands q22–q24 in nine cases and on band q14 in three cases. The chromosome 11 long arm thus appears preferentially rearranged in M5 although this is not apparent in every case. Concomitant study of the mitoses with cytological and cytogenetic techniques suggests that erythroblasts may not be involved in the M5 leukemic process.     

Microtubular spindle dynamics and chromosome complements from somatic cell nuclei haploidization in mature mouse oocytes and developmental potential of the derived embryos

BACKGROUND: The aim of this study was to investigate haploidization of somatic cell nuclei in non-enucleated mature oocytes regarding spindle formation, chromosomes and developmental potential. METHODS: Mouse cumulus cells were injected into metaphase II oocytes. Some injected oocytes were examined for morphological changes of chromosomes and the spindle immediately, and at 30 min, 1 h or 2 h after the injections. The remaining oocytes were activated by Sr(2+) after various incubation periods and observed for formation of a second polar body and pseudo-polar body. Cytogenetic analysis was performed for some of the resulting zygotes. The progress to blastocysts in vitro and the possibility of conception in vivo were assessed. RESULTS: Immediately after injection, the cumulus cell nucleus was still in interphase without spindle formation. The occurrence of premature chromosome condensation (PCC) and spindle formation increased as the incubation time increased. The percentages of activated oocytes increased with the incubation time after nuclear transfer, but the difference was not significant between 1 (58%) and 2 h (62%). The incidence of chromosomal aberrations was high for the derived embryos. Development in vitro was poor, and no procreation of pups occurred after transfer of the 324 embryos. CONCLUSIONS: The PCC and spindle formation induced by cumulus cell nuclei in mature oocytes was time dependent, as was the chance for successful activation. The chromosomal abnormalities from segregation errors presented one obvious cause, apart from the potential epigenetic defects, of developmental failure of the semi-cloned embryos.     

小鼠体外成熟与激素超排卵母细胞核型分析

目的：评价激素超排(HIO)和体外培养成熟(CVM)两种方法对小鼠卵母细胞染色体的影响。方法：通过HIO与CVM分别获得100个、80个成熟小鼠卵母细胞,制备染色体标本进行核型分析。结果：在HIO组,超单倍体率、非整倍体率、染色体结构畸变率、结构畸变卵母细胞率、退化卵母细胞率和染色体分离均数依次为2,0％、4．0％、2．0％、2．0％、8．0％和0．13;在CVM组,上述实验参数依次为4．O％、8．O％、7．5％、6．3％、12．5％和O．325;两组所有实验参数经统计学处理没有显著差异。结论：经体外培养成熟的与经激素超排的小鼠卵母细胞其质量和染色体核型没有本质上的差异。将此结果外推到人类,提示未成熟卵母细胞经体外培养成熟在人类辅助生殖领域具有广泛的应用前景。     

Clinical relevance of genomic aberrations in homogeneously treated high-risk stage II/III breast cancer patients

Little is known about the prognostic impact of chromosome aberrations in breast cancer. The aim of our study was to determine whether genomic aberrations of prognostic relevance can be identified in the context of a clinical study using molecular cytogenetics. Paraffin-embedded tumor samples of 44 patients with high-risk stage II/III breast cancer were analyzed by comparative genomic hybridization. All patients received identical therapy including dose-escalated chemotherapy followed by peripheral blood stem cell transplantation. The most frequent chromosomal aberrations were gains on chromosome arms 17q (24 cases), 1q (21 cases), 8q (17 cases), 20q (13 cases), 6p (9 cases) as well as losses on chromosome arms 13q (25 cases), 11q (20 cases), 5q (11 cases), 6q (11 cases), 9p (10 cases), 18q (10 cases), 8p (9 cases) and 16q (9 cases). In univariate analysis, the correlation with the clinical outcome revealed a higher risk for patients with tumors exhibiting 13q losses and a reduced risk for tumors exhibiting 16q losses (p = 0.020), 6q losses (p = 0.041) and estrogen-receptor positivity (0.051). In multivariate analysis using the Cox model, only the loss of 16q exhibited borderline significance (p = 0.065). These data show that comparative genomic hybridization can be performed in the context of a clinical trial. In our subgroup of high-risk breast cancer patients, chromosomal aberrations were valuable prognostic parameters.     

Increasing genome instability in adrenocortical carcinoma progression with involvement of chromosomes 3, 9 and X at the adenoma stage

The investigation of chromosomal aberrations in adrenocortical tumours has been limited by the difficulties of applying classical cytogenetics to tumours with low levels of proliferation. We have therefore applied the technique of interphase cytogenetics to paraffin-embedded archival specimens of 14 adrenocortical adenomas and 13 carcinomas. Hybridizations were performed using centromere-specific probes to chromosomes 3, 4, 9, 17, 18 and X, which have been shown to be altered in other types of tumours. Chromosomal imbalance was defined on the basis of changes in both chromosome index (CI) and signal distribution (SD). Where only one of these was altered, this was classified as a tendency to gain or loss. On the basis of the analysis of optimal hybridizations, carcinomas showed gains in all chromosomes studied, five of nine showing gains in multiple chromosomes. Gains were most common in chromosomes 3, 9 and, in particular X, eight of 11 showing gain, and one a tendency to gain. Chromosomal gain was seen less commonly in adenomas, but again chromosomes 3, 9 and X were involved. Losses were infrequent, only one carcinoma showing loss of chromosome 18, and adenomas showing a tendency to loss of chromosomes 4 (two cases), 17 (one case) and 18 (two cases). Our data suggest that changes in chromosomes 3, 9 and X are early events in adrenocortical tumorigenesis, and that there is increasing chromosomal instability with tumour progression.     

男性肾透明细胞癌性染色体数目异常及其临床意义

目的:探讨性染色体数目异常与男性肾透明细胞癌病理分级及临床分期之间的关系。方法:将20例男性肾透明细胞癌按照病理分级和临床分期分组,并选择5例正常肾组织作为阴性对照,用荧光原位杂交技术分析各例肿瘤细胞及对应癌旁细胞性染色体数目变异情况。以性染色体的获得和缺失为变异指标,分析其和肾癌病理分级及临床分期之间的关系。结果:肾癌细胞中性染色体获得显著高于癌旁及正常组织中的细胞(P0.05);低分化组中肿瘤细胞性染色体获得高于高分化组(P0.05);进展性肾癌较局灶性肾癌更易发生性染色体获得(P0.05)。结论:男性肾透明细胞癌细胞性染色体的获得与肿瘤病理分级和临床分期有相关性。     

The ZW Pairs of Two Paleognath Birds From Two Orders Show Transitional Stages of Sex Chromosome Differentiation

Pachytene oocytes from the two presumably most primitive orders (Paleognathae) among living birds were used to study the pairing behaviour and location of recombination nodules (RNs) in the sex pair. In the ratite Pterocnemia pennata (Rheiformes), the 42 analyzed ZW pairs show an average of 2.2 RNs distributed along 80% of the synaptonemal complex (SC) that covers the long arm of the acrocentric Z and W chromosomes in this homomorphic sex pair. In the tinamid Rynchotus rufescens (Tinamiformes), the 60 analyzed ZW pairs show an average of 1.35 RNs distributed along 66% of the SC covering most of the long arms of this visibly heteromorphic ZW pair. RNs are non-randomly distributed and show interference in both species, but in the tinamou they are restricted to a significantly smaller stretch. The discovery of an intermediate degree in the restriction of RN location, between the extremes of free recombination along most of the W in ratites and strict localization of a single RN in Neognath birds, suggests its relationship with the mechanism of sex chromosome differentiation among Aves. This revised version was published online in August 2006 with corrections to the Cover Date.     

The stability of chromosomes in yeast

Summary CL mutants with high instability of chromosome III were UV-induced in haploid strain disomic for chromosome III. The obtained CL mutants can be divided into two groups: (1) CL2, CL3, CL7, CL11–L13 with elevated level of spontaneous inter- and intragenic recombination and (2) CL4, CL8 in which instability of chromosome III is not accompanied by elevation of mitotic recombination frequency. CL4 and CL8 mutants also show unstable maintenance of artificial minichromosomes with different chromosomal replicators and centromeric loci. The instability of chromosome III and minichromosomes in CL4 and CL8 is determined by two nonallelic genes designated ch14 and ch18. The role of ch14 and ch18 genes in mitotic chromosome transmission is discussed.     

Molecular analysis of multiple cytochrome P450 genes from the malaria vector,Anopheles gambiae

Cytochrome P450s are a superfamily of haemoproteins, important in the metabolism of endogenous compounds and xenobiotics. As a first step to elucidating the role of this family in insecticide resistance in the malaria mosquito, Anopheles gambiae, we have cloned and mapped multiple P450 genes. Sixteen cDNAs encoding full-length P450s were cloned and physically mapped to the mosquito's polytene chromosomes. Fourteen of these encode putative CYP6 proteins and two encode P450s belonging to the CYP9 class. Eighteen new A. gambiae Cyp4 P450 genes were identified using degenerate PCR primers, cDNAs were detected for ten and in situ locations for thirteen members of this gene family.