Unusual segregation of t(11;22) resulting from crossing-over followed by 3:1 disjunction at meiosis I

Reciprocal translocation t(11;22)(q23;q11) is of particular interest because the unbalanced offspring of the translocation carriers usually present with a supernumerary derivative chromosome 22. This common unbalanced karyotype is the result of 3:1 chromosome segregation during meiosis. We report the third case of a rare segregation pattern of a paternal 11; 22 translocation. The proband's karyotype revealed the presence of a der(11) and two copies of a der(22), i.e. 47, XX, t(11; 22)(q23;q11), +der(22) t(11;22)pat. The karyotype is the result of paternal 3:1 segregation after crossing-over involving the derived and the normal chromosome 22, as revealed by chromosome polymorphism analysis. Contrary to the preferential maternal transmission of this common unbalanced translocation, the data from the literature, including our case, may suggest preferential paternal transmission of this rare type of unbalanced translocation.     

Use of acetylcholine (Ach) for spreading metaphase chromosomes and application to the cytogenetic analysis of human stomach cancers

Cytogenetic studies of biopsy specimens endoscopically obtained from gastric cancers were performed in our laboratory. The necessity for well-spread chromosomes for analysis has resulted in the development of a new technique, in which culture medium containing acetylcholine (Ach) is used; with this new technique, the number of metaphases of analyzable karyotypes was significantly increased (P<0.01 compared with a previous method in which Ach was not used). The mean ratio of metaphase numbers of analyzable karyotypes in four cases in which Ach was used was 38.1±8.1%, a value more than four times the number in the seven cases in which Ach was not used. It is possible that Ach may decrease the viscosity of the cytoplasm in gastric cancer cells by disrupting microfilaments.     

烹调油烟对小鼠骨髓细胞染色体畸变率和微核率影响的研究

本文在昆明种小鼠吸入不同浓度（28，67，100mg／M3）烹调油烟（COF）的情况下，观察小鼠骨髓细胞染色体畸变率和嗜多染红细胞（PCE）微核率。实验结果显示，吸入COF各剂量组小鼠骨髓细胞染色体畸变率和微核率均随COF浓度上升而增高（P＜0．05），且呈剂量反应关系，两率相关系数为0．88，表明COF进入体内后具有一定的体细胞诱变活性。     

Supernumerary chromosomes in filamentous fungi

Within a fungal species, a subset of individuals may have more than the minimal complement of chromosomes. If the extra chromosomes are composed primarily of DNA not found in all representatives of the species, they are most appropriately referred to as supernumerary chromosomes. The patterns of repeated DNA sequences on certain supernumerary chromosomes suggest that they have a different evolutionary history from the essential chromosomes in the same genome. Supernumerary chromosomes can carry functional genes and, in at least two fungal species, genes on such chromosomes play important roles in host-pathogen interactions. Supernumerary chromosomes that confer an adaptive advantage in certain habitats, such as the ability to cause disease on a specific host, may be referred to as “conditionally dispensable” chromosomes in order to reflect their importance in some, but not all, growth conditions. In addition to describing the structural and functional characteristics of known supernumerary chromosomes in fungi, this review discusses the relative merits of the terms that have been used to describe them, and establishes experimental criteria for their identification. Received: 20 April / 23 April 1998     

Mild phenotypic manifestations of terminal deletion of the long arm of chromosome 4: clinical description of a new patient

We present clinical and developmental data on a patient with a de novo terminal deletion of the long arm of chromosome 4. Cytogenetic studies after G-banding revealed the karyotype 46,XY,del(4)(q34). The 4-year-old male showed mild facial dysmorphism, moderate mental retardation with speech retardation, and marked deficits in gross motor skills. Our patient is the second with this deletion described in the literature. In both patients the phenotype was characterized by mild to moderate mental retardation, abnormalities of the pinnae, and nonspecific facial dysmorphism. The mild phenotype might explain why only two patients with this deletion have been described so far.     

肺腺癌耐药细胞株生物学特性及染色体分析

目的：建立氯氨顺铂诱导肺腺癌耐药细胞株SPC-A-1／CDDP，分析SPC—A-1／CDDP生物学特性及染色体核型，为肺腺癌的治疗提供实验依据。方法：采用氯氨顺铂（Cis—Diaminodichloroplatin，CDDP）大剂量冲击＋逐步诱导法建立肺腺癌耐药细胞株SPC—A-1／CDDP，MTT法检测细胞耐药指数，生物发光法测定细胞能量代谢，流式细胞仪测试细胞周期，染色体G显带技术和光谱核型分析（spectral karyotyping，SKY）技术分析染色体变化。结果：MTT检测结果表明，SPC—A—1／CDDP对7种不同的化疗药物表现了不同的耐药性，其ATP、ADP、AMP含量显著降低，细胞周期无明显变化。G显带结果表明SPC—A-1／CDDP染色体为亚三倍体，SKY分析出现数条衍生染色体。结论：CDDP可以成功诱导肺腺癌耐药细胞株SPC—A-1／CDDP，SPC—A-1／CDDP衍生染色体可能与肺腺癌耐药有关。     

急性髓细胞白血病细胞CD34抗原表达的临床及生物学意义

为研究ＣＤ３４在急性髓细胞白血病（ＡＭＬ）中的临床及生物学意义，用流式细胞术检测了１０７例ＡＭＬＣＤ３４表达。结果显示４８．５％的患者ＣＤ３４阳性表达，Ｍ３（１５．８％）低于其他亚型（ｐ〈０．０５）。ＣＤ３４＾＋者肝脾肿大常见。ＣＤ３４表达在ｔ（８；２１）、正常核型及ｔ（１５；１７）组分别为７２．０％、４０?７％及１７．６％。ＣＤ３４＾＋者的完全缓解率（４１．９％）明显低于ＣＤ３４＾－者的５９．６     

The molecular aetiology of haemophilia A in a New Zealand patient group

The genetic basis of haemophilia A (HA) is well-established, and many haematology services are supported by molecular biology laboratories that offer factor VIII genetic testing for HA patients. This report describes the results from factor VIII gene (F8) analysis of a New Zealand cohort of 45 proband HA patients. We screened all proband HA patients attending local clinics to determine the molecular basis of disease in each case. We also aimed to evaluate the significance of founder effect in this population and to explain an unusual case of HA in a female patient. HA patients were screened for the common F8 gene inversion mutations using previously described PCR-based techniques, and for single base substitution mutations using denaturing high performance liquid chromatography and DNA sequencing. Analysis of microsatellite markers located within or near F8 was used to determine identity by descent and trace inheritance patterns of disease alleles. X-chromosome inactivation (XCI) patterns were detected using methylation specific PCR. Pathogenic F8 gene mutations were detected in all 45 HA patients in this cohort and non-random XCI was confirmed in a female haemophiliac. We report nine novel F8 mutations, including two splicing mutations, a five nucleotide deletion and a large deletion at the 5' end of the gene. The molecular aetiology of HA was similar to that described in other studies but the distribution of mutations was unusual due to founder effects, with almost a quarter of all probands being descended from just three individuals.     

三硝基甲苯的遗传毒性研究

用果蝇伴性隐性致死（ＳＬＲＬ）实验和非整倍体检测实验，对三硝基甲苯（ＴＮＴ）的遗传毒性进行了研究。结果表明：雄性果蝇在５４．０ｍｇ、２７．０ｍｇ、１３．５ｍｇ／１００ｍｌ培养基浓度下喂饲２４小时，在ＳＬＲＬ实验中，可引起生殖细胞隐性致死率明显增加，并有明显的剂量反应关系；在非整倍体检测实验中，Ｘ或Ｙ染色体丢失率明显增加，也有明显的剂量反应关系。说明ＴＮＴ对果蝇生殖细胞具有明显的致突变作用。分阶段（２，３，３天）实验表明，ＴＮＴ对果蝇各阶段生殖细胞具有相同的致突变作用。     

裸鼠高致瘤性人白血病细胞系染色体核型分析

目的 :探讨人白血病细胞系 K5 6 2 - n和 HL6 0 - n在裸鼠体内高致瘤性的细胞遗传学机制。 方法 :对裸鼠体内致瘤性不同的 K5 6 2细胞、K5 6 2 - n细胞及其衍生的各克隆株和 HL- 6 0细胞、HL6 0 - n细胞及其衍生的各克隆株 ,进行染色体核型分析。 结果 :K5 6 2细胞染色体数目变异范围为 44～ 71,干系核型为亚三倍体 ,染色体众数为 6 2± 2 ;裸鼠高致瘤性 K5 6 2 - n细胞系 ,干系为近二倍体细胞 ,染色体众数为 46 ;分析比较致瘤性不同的 K5 6 2、K5 6 2 - n细胞及其无致瘤性克隆株 K5 6 2 - n/ A的核型 ,发现 1、2、11、12、16、18、2 0、2 1、2 2等染色体的改变与 K5 6 2 - n细胞系的致瘤性增高有关。 HL- 6 0细胞染色体数目变异范围为 38～ 71,干系为近二倍体细胞 ,染色体众数为 45± 1;裸鼠高致瘤性 HL6 0 - n细胞系 ,干系核型转变为近三倍体 ,其染色体众数为 6 3± 1,HL6 0 - n细胞系衍生的 HL6 0 - A、HL6 0 - B、HL6 0 - E、HL6 0 - F各克隆株也都是近三倍体 ;分析比较 HL- 6 0细胞系及HL6 0 - n细胞系不同致瘤性克隆株的染色体核型变化 ,发现 Mar3、19、2 1、2 2、5号等染色体的变化与 HL6 0 - n细胞的高致瘤性相关。 结论 :K5 6 2 - n、HL6 0 - n细胞系致瘤性的增高涉及多条染色体的复杂变化。