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H Dosik

Publications and source records attributed to H Dosik.

At least 37 records · Page 2Linked to original sources
PubMed1986

A possible cause of non-disjunction of additional chromosome 21 in Down syndrome.

A possible cause of non-disjunction of chromosome 21 in Down Syndromes has been cytogenetically evaluated by examining the parents by Ag-staining technique. In all the cases studied so far, the contributing parents have active ribosomal cistrons on both chromosomes 21 i.e. both chromosomes are stained positively by silver staining. These results show that the active NORs might play an essential role in meiotic non-disjunction. Furthermore, the preliminary results demonstrate that the acrocentric associations of homologous and non-homologous nature involving chromosome 21 are the most frequent in the contributing parent which may further indicate the role of multiple cellular factors affecting the associations in promoting the nondisjunction in addition to active NORs. The possible mechanisms regarding the non-disjunction of chromosome 21 have been described.

Child↗
PubMed1986

Role of heterochromatin during preferential 9q;22q translocation in chronic myelogenous leukemia.

The secondary constriction region (h) of human chromosome 9 was evaluated in 55 chronic myelogenous leukemia (CML) patients with respect to its size and position. Each case was examined by C-banding and distamycin A-4,6-diamidino-2-phenylindole techniques for the expression of the h regions. When one h region of chromosome 9 was larger, it was more frequently involved in the reciprocal translocation with chromosome 22. In addition, there was a higher incidence of pericentric inversions in the h regions in the translocated chromosome 9 when compared with normal homologues. The role of the constitutive heterochromatin of chromosome 9 as a possible influencing factor during 9q;22q translocation in CML is suggested.

Chromosome Banding↗
PubMed1985

Evidence of a new chimeric bcr/c-abl mRNA in patients with chronic myelocytic leukemia and the Philadelphia chromosome.

The hallmark of chronic myelocytic leukemia is the presence of the Philadelphia chromosome (Ph1). In recent studies, we obtained data that strongly suggested the involvement of an oncogene, c-abl, in this type of leukemia. This oncogene, normally located on chromosome 9, is translocated to chromosome 22 as a result of the Ph1 translocation. In addition, we identified a region on chromosome 22, the breakpoint cluster region (bcr), which contains the chromosomal breakpoint in all patients with chronic myelocytic leukemia who are positive for Ph1. Recent studies have suggested that the bcr is part of a gene that is truncated as a consequence of the Ph1 translocation. The deleted part of this gene could be replaced by c-abl sequences; to test this hypothesis we analyzed the RNA of five patients with chronic myelocytic leukemia. All five had chimeric bcr/c-abl messenger RNA, suggesting that the deleterious effects of this disease can be associated with an abnormal chimeric protein encoded by the bcr and the c-abl oncogene.

Adult↗
PubMed1985

Unusual translocations involving chromosomes 12;22 and 9;12 in a case of chronic myelogenous leukemia.

A case of chronic myelogenous leukemia (CML) with highly unusual translocations involving both chromosomes #12 is reported. The origin of the Ph1 chromosome was due to a 12p/22q translocation. Chromosome #9 was involved in a translocation with the other chromosome #12. By critical examination of the "size" of the Philadelphia chromosome, it was noted that the breakpoints on 22q were different when compared with a previous case (see Verma and Dosik [16]), although the short arm of chromosome #12 (12p) was involved in both instances. So far, no apparent differences in the course of the disease have been attributed to the types of translocation observed in these cases.

Adult↗
PubMed1985

"Masked" Ph1-chromosome in chronic myelogenous leukaemia (CML).

The CML patients with so called masked Ph1-chromosome have been reviewed. Although the importance of c-sis and c-abl oncogenes is gaining popularity yet their role in the genesis of CML remain obscure. Patients with masked Ph1-chromosomes where chromosome 9 is not involved in the translocation(s) will provide a clue to the role of c-abl and/or c-sis in oncogenesis.

Chromosome Deletion↗
PubMed1985

Extramedullary presentation of blast crisis in chronic myelogenous leukemia.

We present a case with the clinical and pathological impression of Ph1-positive chronic myelogenous leukemia in extramedullary blast crisis involving lymph nodes as demonstrated by morphological and cytogenetic studies. The hyperploid cell lines that were present in the lymph node were not present in the bone marrow. The present case demonstrates that cytogenetic and morphological studies of extramedullary organs are helpful in the confirmation of the diagnosis of blast crisis, especially when lymph nodes are the site of original presentation.

Adult↗
PubMed1984

Chromatin of h regions of human chromosomes at high resolution.

Segmentation of the secondary constriction region (h) of human chromosomes 1, 9 and 16 is demonstrated by a high resolution banding technique. Based on these staining properties, it is suggested that the composition of the h region in human chromosomes is heterochromatic as well as euchromatic.

Chromatin↗
PubMed1984

Chromosome fragility in Bloom's syndrome cell line GM 1492.

Chromosomal aberrations in skin fibroblasts from Bloom's syndrome cell line GM 1492 are described. As expected, the sister chromatid exchange (SCE) frequency was high. Four very common chromosomal rearrangements included dup( 6q ), t(13;15), dic(16), and del(11q). The nucleolar organizer regions (NOR) in the dicentric t(13;15) were active. The increased incidence of chromosomal markers suggests an evolution of clones in the cell line.

Bloom Syndrome↗
PubMed1984

Peripheral location of the Y chromosome: relationship to race and length heteromorphism.

In the present report we examined the position of the Y chromosome with respect to its size and race to determine their relationship to its peripheral location. Peripheral blood lymphocytes were cultured from 172 normal male individuals (70 Asian Indians; 49 American Blacks; and 53 Caucasians) and 2770 QFQ cells were photographed. The length of the Y chromosome was classified into four groups i.e., small, average, large and very large as described earlier (Verma et al., J. Med. Genet., 15, 227-281, 1978). The average incidence of peripheral location of all races for small, average, large and very large was 3.64, 5.84, 10.51 and 11.17 per cent respectively. For blacks and caucasians, the peripheral location was influenced by its size while the incidence remained the same for Indians for all sizes. Consequently, it is presumed that the position of the Y chromosome in somatic metaphases depends upon race as well as its size. Furthermore, we have provided a method for determining the position of the Y chromosome which should suffice for most situations.

Asian People↗
PubMed1984

Random single chromatid and nonrandom double chromatid type segregation of human acrocentric chromosomes in BrdU-labeled mitoses.

Chromatid segregation was analyzed using satellite association of 5-bromodeoxyuridine (BrdU) differentially stained acrocentric chromosomes of human leukocytes. Data were classified into cis and trans configurations in second and third division cycles. It was found that single chromatid types have random segregation (1:1) while nonrandom segregation was noted for double chromatid types. The nonrandom segregation hypothesis of earlier investigators needs to be reexamined.

Bromodeoxyuridine↗
PubMed1984

Are breakpoints variable on the long arm of chromosome 5 (5q-) in patients with refractory anemia?

A 74-year-old female was referred with a diagnosis of refractory anemia (RA). Direct bone marrow preparation without phytohemagglutinin-stimulated lymphocytes revealed an abnormal karyotype in 50% of the cells. By RFA technique, it was determined that chromosome 5q had a terminal deletion (band 5q31----qter). A review of cases of RA in which 5q is involved shows that the deleted segment varies from case to case.

Aged↗
PubMed1984

Expression of ribosomal cistrons of human chromosomes at high resolution.

The expression of ribosomal cistrons in the nucleolar organizer regions (NORs) has been studied with high resolution banding in the acrocentric chromosomes of 10 normal individuals. It was found that if a particular chromosome did not stain with silver nitrate at metaphase, then it did not stain at prophase either. Therefore, it is concluded that some of the acrocentric chromosomes have variable expression of NORs.

Adult↗
PubMed1983

Preferential association of nucleolar organizing human chromosomes as revealed by silver staining technique at mitosis.

The frequency of different types of satellite associations of nucleolar organizing human chromosomes (i.e. acrocentric chromosomes; 13, 14, 15, 21, and 22) is reported using 10 normal individuals by Ag-staining technique. The preferential involvement of acrocentric chromosomes in satellite association is suggested. Only acrocentric chromosomes with active NORs (i.e. Ag-stained) were found in association while unstained (inactive NORs) chromosomes were never seen in satellite association. In general as number of NORs expression increase, the frequency of association per cell was also increased. A possible mechanism and the clinical consequences of such an unusual phenophenon is described.

Chromosomes, Human, 13-15↗
PubMed1983

Racial variation of a non-fluorescent segment of the Y chromosome in East Indians.

Seventy normal male East Indians were selected to study the length of the fluorescent (f), non-fluorescent (nf), and total length of the Y chromosome by the QFQ technique. The length of the Y chromosome was classified into five groups using subjectively defined criteria, namely, very small, small, average, large, and very large. The frequencies of Y/F indices for these groups were 0.0%, 1.42%, 15.71%, 58.57%, and 24.28%, respectively. The variation in the total length of the Y chromosome was accounted for by variations in the length of the nf as well as the f segments. The mean Y/F, f/F, and nf/F indices for East Indians were 1.20, 0.47, and 0.73, respectively. A longer Y was noted in East Indians primarily owing to an increase in size of the nf segment in comparison to normal black and Caucasian populations. Furthermore, it is emphasised that the definition of 'average' or 'large' Y varies from race to race.

Adult↗