Biomedical subjects
H Dosik
Publications and source records attributed to H Dosik.
Partial trisomy of chromosome 3 (3q12 leads to qter) owing to 3q/18p translocation. A trisomy 3q syndrome.
In four previously reported patients with partial 3q trisomy, only a small portion of 3q was trisomic (3q21 leads to qter or 3q25 leads to qter). Clinical features in these cases have included the following: low-set ears, mongoloid slant of eyes, hypertelorism, cleft palate, webbed neck, simian creases, short finger, clinodactyly, hypotonia, and low-set hairline. Cytogenetic studies of a premature, 1,680-g female infant with with these clinical features showed this extra material to be part of the long arm of chromosome 3 (3q12 leads qter), which resulted in partial trisomy for this segment, ie, 46,XX,-18, +t (3;18) (q12;p11). Although a larger portion of 3q was involved in this case, the clinical picture was similar to other cases of 3q duplication with or without 3p deletion.
Anthramycin-induced sister-chromatid exchange and caffeine potentiation in the chromosomes of Indian muntjac.
Cell-cycle kinetics, sister-chromatid exchange (SCE) and chromosome aberrations have been studied from the skin fibroblasts of the Indian muntjac after treatment with 100 micrograms/ml of caffeine and 0.05 microgram/ml of anthramycin. The cultures were incubated for a period which was sufficient for the completion of two consecutive cell cycles and both the drugs appeared to produce a slight inhibitory effect. When anthramycin-treated cells were however post-treated with caffeine, the cells did not proceed beyond one cycle and exhibited a mitotic block. The SCE frequency in the control and the experiments with caffeine and anthramycin was 8.63, 18.32 and 34.88 per cell respectively. The SCEs were randomly distributed amongst all chromosomes unlike a non-random distribution within the X chromosomes. Caffeine and anthramycin produced only 0.5% and 3.1 cells with chromosome aberrations respectively. Potentiation of chromosome aberrations was observed when the anthramycin-treated cells were post-treated with caffeine. Caffeine potentiation presumably results from an inhibition of the cells to cycle and a failure to repair the effect of the mutagen on DNA.
Inherited aplastic anaemia with increased endoreduplications: a new syndrome of Fanconi's anaemia variant?
Two sisters with aplastic anaemia without other congenital anomalies are described. Peripheral blood cytogenetic studies revealed an increase in endoreduplications in the absence of other unstable chromosome anomalies. Increased expression of T-antigen following SV40 virus infection in vitro was demonstrated in both sisters, as well as other normal family members. We feel that these patients represent a variant of Fanconi's anaemia. The importance of performing chromosome studies in idiopathic aplastic anaemia is emphasized.
SV40 T-antigen expression in acute non-lymphocytic leukaemia.
Susceptibility to SV40 virus infection has been suggested as an in vitro marker of predisposition to leukaemia and possibly other cancers in man. To evaluate this relationship, sporadic as well as familial cases of acute non-lymphocytic leukaemia were tested. Among skin fibroblast lines from 22 patients without family history of leukaemia, eight had values above the 95% confidence limit for the normal control population. In four leukaemia-prone families, elevated T-antigen expression was found in all four patients tested and in three-quarters of 36 blood relatives. In addition, elevated values were found in two of three cases of acute myelogenous leukaemia associated with constitutional cytogenetic anomalies, and in all three cases with preleukaemic haematologic disorders. Since SV40 T-antigen expression was elevated in most persons prone to acute non-lymphocytic leukaemia, as well as over one-third of sporadic cases, heritable risk factors may be involved in both groups.
Alpha thalassaemia in American blacks: a study of a family with five cases of haemoglobin H disease.
Five cases of HbH disease were discovered in a large family of American Blacks. Anaemia was mild with PCV ranging from 0.275 to 0.405. The amount of HbH was 2--6%. Studies of haemoglobin synthesis in peripheral blood reticulocytes demonstrated marked deficits in alpha globin production with an average alpha/beta ratio of 0.31 (range 0.22--0.36). Eighteen additional family members had evidence of thalassaemia trait and were provisionally classified as either alpha-thal-1 (average MCV 65.2 fl; range 59--70) or alpha-thal-2 (average MCV 79.6 fl; range 74--88). A subject with altha-thal-1 trait had an alpha/beta ratio of 0.56; the average for five cases of alpha-thal-2 was 0.73. One other family member was thought to be homozygous for alpha-thal-2 trait and exhibited an MCV of 65 fl with an alpha/beta ratio of 0.5. These data reconfirm that in Blacks with alpha thalassaemia the proportion of HbH is lower and the severity of anaemia is less than in certain other racial groups, e.g. Southeast Asians. However, the degree of hypochromia and microcytosis and the imbalance in alpha and beta globin synthesis appear to be similar in Blacks and other races. These results suggest that the milder clinical course of HbH disease in Blacks is not a result of greater alpha globin production in that population of thalassaemics.
The technical variables associated with the frequencies of QFQ, RFA and CBG heteromorphisms of human chromosomes.
In the 1971 Paris Conference (1972) it was established that certain regions of human chromosomes show remarkable heteromorphisms. These are the short arm of acrocentric chromosomes, the secondary constriction regions of chromosomes 1, 9, 16, and the distal 2/3rd of the long arm of the Y and the centromere of chromosomes 3, 4, and 5. There are several technical variables which affect the frequency of these heteromorphisms. These include quality of culture, age of slide, photography (filter, etc.), method of printing and method of scoring (criteria). Several other variables in the production of QFQ, RFA, and CBG heteromorphisms are discussed. In order to compare results from different laboratories these variables must be taken into consideration.
Frequencies of centromeric heteromorphisms of human chromosomes 3 and 4 as detected by QFQ technique: can they be identified by RFA technique?
One hundred normal Caucasians were studied by sequential QFQ and RFA banding techniques in order to estimate the type and frequency of heteromorphisms in the centromeric regions of chromosome 3 and 4. Intensity variants were classified into 1 of 5 levels of QFQ banding. QFQ intensity heteromorphisms (greater than or equal to level 3) for chromosomes 3 and 4 were 62 and 15 percent respectively. The interrelationship between QFQ and RFA variants were also examined. When the centromere was brilliant by QFQ, it was found that it was deep red by RFA; when it was pale by QFQ, it was light red by RFA. Neverthless, a blind coded study could not pick up these color variants by RFA. QFQ banding showed variations of the centromeric regions of chromosomes 3 and 4 while RFA banding failed to demonstrate it. It was concluded that QFQ is the most useful technique in detecting the different intensity levels in the centromeric regions of chromsomes 3 and 4.
A case of chronic myelogenous leukemia (CML) with a translocation between chromosomes 12 and 22, t(12;22)(p13;q13), resulting in a Philadelphia (Ph1) chromosome.
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Structural organization of chromosomes of the Indian muntjac (Muntiacus muntjak).
The identification, morphology, and banding pattern of the chromosomes of the Indian muntjac (Muntiacus muntjak) are described. A diagrammatic representation of the banding pattern as revealed by various techniques is presented following the nomenclature suggested by Paris Conference (1971) for human chromosomes. The Y2 chromosome and the neck of the X chromosome are late replicating based on observations made with the use of a bromodeoxuridine plus Giemsa technique. Most of the G-bands are early replicating, contrary to earlier findings based on autoradiography.
Purulent pericarditis in acute leukemia.
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SV40 T-antigen expression in cultured fibroblasts from patients with Down syndrome and their parents.
Expression of simian papovavirus 40 (SV40) T-antigen following in vitro infection was studied in skin fibroblasts from patients with Down syndrome (DS) and their parents to determine whether the increased susceptibility to SV40 infection reflected the cytogenetic defect or the leukemia risk associated with this syndrome. As a group, fibroblasts from patients with DS showed elevated T-antigen expression 72 hrs after infection compared to that of a healthy control population. However, among 24 patients tested, the cell lines of only 11 showed statistically significant increases in T-antigen expression. A cell line from a patient with concurrent DS and acute myelogenous leukemia had a normal value. T-antigen expression did not correlate with the percentage of cells trisomic for chromosome 21 in 18 cell lines examined or with the number of copies of this chromosome in disomic and trisomic cell strains cloned from three mosaic patients.Collectively, cell lines from parents of trisomy 21 patients also showed increased susceptibility to SV40 infection; however, in five families tested, a consistent pattern of genetic transmission of elevated T-antigen expression from parent to offspring was not observed. Q-banding of cell lines in one family showed that elevated T-antigen expression is not a marker of parental nondisjunction. Variation in susceptibility to human interferon, an antiviral agent, did not account for variation in T-antigen levels among these cell lines. Thus, the abnormalities of T-antigen expression in DS appear independent of the hyperdiploid state and are not a sensitive indicator of cancer risk.
Clinical significance of the satellited short arm of human chromosome 17 (17ps +) : a rare heteromorphism?
A 43-year-old impotent male Caucasian had a chromosomal constitution of 46,XY,17ps+. The satellited chromosome 17 was also present in his sister. There is no suggestive evidence that this satellited chromosome causes any clinical abnormality. Based on multiple banding techniques, it is concluded that the 17ps+ is a rare chromosomal heteromorphism.
Precise identification of human chromosomal abnormalities.
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A simplified technique for simultaneous staining of nucleolar organizer regions and kinetochores.
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Prevention of neonatal hepatitis B infection by high-dose hepatitis B immune globulin.
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Centromeric banding (C) of sequentially Q- and R-banded human chromosomes.
A modified C-banding technique is described that produces C bands on human chromosomes after sequential Q and R banding and retains good chromosome morphology. Despite the considerable exposure to UV light during sequential Q and R bandings, clear C bands could still be achieved. Employing the present technique, Q, R, and C polymorphisms can be recorded on a single metaphase.
Ring chromosome 13 in a child with minor dysmorphic features. Irregular phenotypic expression of ring 13 syndrome.
A patient with ring chromosome 13 had some physical and stigmata that to our knowledge have not been reported in previous articles. These include alopecia, scattered pigmentation, trigonocephaly, and telecanthic fold. This case reemphasizes how mitotic instability can produce clinical features during the critical period of organogenesis.