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Biomedical subjects

H Dosik

Publications and source records attributed to H Dosik.

At least 73 records · Page 4Linked to original sources
PubMed1981

Sister chromatid differentiation and isolabeling of chromosomes.

Isolabeling observed during sister chromatid differentiation (SCD) was studied from human skin fibroblasts by the fluorescence-plus-Giemsa (FPG) technique. Bromodeoxyuridine (BrdU) was fed to exponentially dividing cells for 52 h to enable completion of two consecutive cycles of DNA replication. During this period, the late-replicating regions of some chromosomes were able to go through three replication cycles. These chromosome regions had evidently incorporated BrdU bifiliarly in both chromatids and hence, on staining with FPG, appeared isostained (isolabeled). Thus, incubation of exponentially dividing cells with BrdU for a period longer than that required for two cell cycles appears to be a suitable method for revealing the late-replicating regions of the genome, such as the X chromosome in a human female, as isolabeled. In another experiment with Indian muntjac chromosomes, isolabeled segments were darkly stained, which suggested unifilar incorporation of BrdU. In this case, unequal crossing-over or an unequal distribution of thymine residues probably is responsible for the isolabel.

Animals↗
PubMed1981

Human chromosomal heteromorphisms in American blacks. III. Evidence for racial differences in RFA color and QFQ intensity heteromorphisms.

One hundred normal American Blacks (B) were studied by sequential QFQ and RFA banding techniques in order to estimate the type and frequency of heteromorphisms. Color heteromorphisms were classified into one of six colors by RFA and intensity variation into one of five levels by QFQ. The data are compared with a previously studied Caucasian population (C). The frequencies of QFQ and RFA heteromorphisms were significantly higher in the Black than in the Caucasian population. No racial difference was noted for chromosome 21 by QFQ, while RFA demonstrated a clear difference. It is concluded that the maximum characterization of racial differences of human chromosomal heteromorphisms was far greater by RFA than with QFQ. The present study suggests differences in QFQ and RFA heteromorphisms among the two races.

Black People↗
PubMed1981

Population heteromorphisms of Ag-stained nucleolus organizer regions (NORs) in the acrocentric chromosomes of East Indians.

The nucleolar organizer regions (NORs) of acrocentric chromosomes in 70 normal East Indians were examined by Ag-staining (NSG) and acridine orange reverse banding (RFA) techniques. The Ag-stainability of NORs was variable from one individual to another but characteristics were constant within each individual. The average modal number of Ag-positive NORs per individual was eight. A racial difference in the expression of NORs is suggested. To study the heteromorphism of NORs, the NSG technique was found to be more useful than RFA. Furthermore, it is concluded that there is no direct relationship between a heteromorphism of NORs identified by NSG and that identified by the RFA technique. Quantitative data on these differences is provided. In addition NOR-regions are classified into five sizes namely; very large, large, medium, small, and very small using subjectively defined criteria.

Acridine Orange↗
PubMed1981

17p+ in a patient with chronic myelogenous leukemia (CML): its differentiation from an isochromosome 17,[i(17q)].

Bone marrow chromosomes are usually of such poor quality as to make it difficult to band them with QFQ or GTG techniques. Because of the possibility that many nonrandom chromosomal abnormalities are present in hematologic disorders, a more reliable banding technique is necessary. Using the RFA technique an abnormality thought to be isochromosome 17, [i(17q)] in a patient with chronic myelogenous leukemia, was revealed to be 17 p+.

Aged↗
PubMed1981

Human chromosomal heteromorphisms in American blacks. IV. Intensity variation in centromeric regions of chromosomes 3 and 4.

One hundred normal American Blacks were studied by q-banding technique in order to estimate the type and frequency of heteromorphisms in the centromeric regions of chromosomes 3 and 4. Heteromorphisms were classified using the scale of five intensity levels namely, negative, pale, medium, intense and brilliant fluorescence. QFQ intensity heteromorphisms (greater than or equal to level 3) for chromosomes 3 and 4 were 54.5 and 7%, respectively. The distribution of different intensities was significantly different in American Blacks compared with Caucasians.

Adult↗
PubMed1981

Variant Turner features in a female with X-isochromosome [46,X, i(Xq)]: is it a distinct clinical entity?

A thirty seven year-old Caucasian female presented with short stature and primary amenorrhea. Employing multiple banding techniques, an isochromosome of the long arm of the X chromosome [i(Xq)] was identified in her peripheral blood and skin fibroblast cultures. This chromosomal abnormality can be interpreted as 46,X,i(X)(qter leads to cen leads to qter). The i(Xq) is late replicating and selectively inactive. The present case was found to have minimal abnormal features when compared with previously published cases. Since patients with i(Xq) have quite variable clinical features, the existence of a distinct clinical entity of "X-isochromosome syndrome" is questioned.

Adult↗
PubMed1980

Relationship of SV40 T-antigen expression in vitro to disorders of bone marrow function.

Skin fibroblasts from patients with a variety of hematologic disorders were infected with SV40 virus in vitro in attempts to discover the reason for increased susceptibility of Fanconi anemia cells to this transforming virus. The proportion of skin fibroblasts expressing SV40 T-antigen by immunofluorescent methods was elevated in 12 patients with Fanconi anemia and in seven of nine obligate heterozygous relatives. Elevated expression was also observed in three patients with other hematological disorders at high risk of acute non-lymphocytic leukemia, but was not apparent in seven sporadic aplastic anemia patients or four of their relatives. T-antigen expression was elevated in about one-half of patients with thrombocytopenia-absent radius syndrome and related conditions, with familial aplastic anemia, and in their normal relatives. In the conditions under study, elevated T-antigen expression seemed clearly correlated with predisposition to leukemia, which may be genetically determined, but it was not associated with cytogenetic or anemic manifestations.

Anemia↗
PubMed1980

Psychosocial aspects of sickle-cell anemia in adolescents.

Until recently emphasis has been placed solely on the physical aspects of sickle-cell anemia. However, a study of twenty-one adolescent sickle-cell patients of both sexes revealed severe emotional and social problems. A task-oriented group approach used with some of these patients had positive results, including free flow of communication, motivation and interest in the group, and increased independence.

Adaptation, Psychological↗
PubMed1980

Heteromorphisms of the Philadelphia (Ph1) chromosome in patients with chronic melogenous leukaemia (CML). I. Classification and clinical significance.

In patients with chronic myelogenous leukaemia (CML), we have found the break points on the long arm of chromosome 22 (22q) are variable (heteromorphic or polymorphic). Consequently, the Philadelphia (Ph1) chromosome is heteromorphic in size for the long arm. Based upon the break points and the relative size of chromosome 22, four types of Ph1 chromosomes are proposed. They are: Types I (very large), II (large), III (average) and IV (small) with the break points at bands 22q13.3, 22q13.1, 22q12 and 22q11.3, respectively. The break points are arbitrary and should not be considered absolute since they are based on length differences. In two cases the Ph1 chromosome involved a translocation between chromosome 9 and 22, and the other two cases chromosome 1 or 12. Because Types I and II are hard to recognize by conventional techniques, the RFA technique (R. band by fluorescence with acridine orange) must be performed on all cases. An earlier contention that only chromosome 22 band 12 is concerned with abnormal myeloid cell proliferation in human leukaemia is rejected. Furthermore, break points are not restricted at the junction of 22ql and q2 and 22q2 and q3 and can happen anywhere on the long arm of chromosome 22.

Acridine Orange↗
PubMed1980

Incidence of major chromosomal abnormalities in a referred population for suspected chromosomal aberrations: a report of 357 cases.

The present report describes the cytogenetic findings in 357 cases referred for suspected chromosomal abnormalities because of abnormal clinical features. Chromosomal anomalies were found in 97 (27.2%) of the cases studied. A significantly high rate of chromosomal abnormalities was found in a population with clinical abnormalities in comparison to an unselected population (0.48-0.55%).

Adolescent↗
PubMed1980

Chromosomal abnormality in the newborns of hepatitis B surface antigen (HBsAg) carrier mothers.

The association of maternal hepatitis B surface antigen carriers (HBsAg) and chromosomal abnormalities in their newborns has been previously suggested. This is a report on two female infants with abnormalities of chromosome 18 and trisomy 3q syndrome who were born to HBsAg carriers. These cases indicate that a possible relationship exists between the HBsAg carrier state in the mother and chromosome abnormalities in her offspring. It is suggested that the parents of all newborns with a structural chromosomal abnormality be tested for HBsAg.

Carrier State↗
PubMed1980

NSG banding of sequentially QFQ and RFA banded human acrocentric chromosomes.

Sequential QFQ, RFA, and NSG techniques have been demonstrated on the same metaphase to facilitate the maximum characterization of human chromosomes with respect to heteromorphic markers. This combination offers an opportunity to compare the results of the RFA and NSG techniques, which are of particular interest as they concern NOR activity. Furthermore, it is useful in studying abnormalities involving acrocentric chromosomes, somatic association, and the regulation of rRNA synthesis.

Chromosome Aberrations↗