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Biomedical subjects

J Stamberg

Publications and source records attributed to J Stamberg.

At least 37 records · Page 2Linked to original sources
PubMed1987

Mitotic recombination can explain the apparent polyclonal origin of some tumors.

Although most human tumors appear to be monoclonal in origin, a few express two G6PD types; on this basis they have been thought to be polyclonal in origin and exceptions to the general rule of monoclonality. In light of the recent discovery that mitotic recombination can cause a shift from genetic heterozygosity to homozygosity in tumor cells, we suggest that such a mechanism can also explain the occasional occurrence of two G6PD types in a monoclonal tumor.

Dosage Compensation, Genetic↗
PubMed1986

Unusual supernumerary chromosomes: types encountered in a referred population, and high incidence of associated maternal chromosome abnormalities.

In a 6-year period 128 patients with supernumerary autosomes were identified in our laboratory. The majority had "primary" trisomy, but 19 (15%) had extra, unusual chromosomes, not just a normal chromosome present in an extra copy. Of these, 18 were complex and did not resemble any one part of the standard chromosome complement. There was a preponderance of females among the 19 cases. Chromosome analysis of the parents in the 14 most recent cases revealed maternal chromosome abnormalities in 11 (79%). Of these 11, eight mothers had balanced reciprocal translocations; nondisjunction led to the smaller of their translocation chromosomes being passed on as the supernumerary chromosome in their offspring. Thus, nondisjunction of maternal translocations accounts for a major proportion of the unusual supernumerary chromosomes found by our laboratory. Advanced maternal age was noted in this group of mothers. Three mothers had supernumerary chromosomes themselves. We conclude that unusual supernumerary chromosomes (1) are not rare among patients referred for chromosome studies; (2) are generally not simple products of breakage; (3) are very frequently the result of malsegregation of a balanced maternal reciprocal translocation; and (4) are very difficult to characterize unless a balanced parental translocation is identified. Parental karyotypes should be obtained whenever a patient has an extra, unusual chromosome.

Adolescent↗
PubMed1986

Somatic shift to homozygosity for a chromosomal polymorphism in a child with acute lymphoblastic leukemia.

A 12-year-old girl with acute lymphoblastic leukemia (ALL) had two types of acquired cytogenetic abnormalities in her pretreatment peripheral blood and bone marrow: hyperdiploidy due to tetrasomy 8, 10, and 21; and, in the hyperdiploid cells, a shift from heterozygosity to homozygosity for a polymorphic variant on chromosome 15. Both abnormalities disappeared after chemotherapy, when the patient entered clinical remission. It has recently been found that shifts to homozygosity occur in retinoblastoma and Wilms' tumor. Our observation extends this finding to leukemia and indicates that such shifts may have general importance in tumorigenesis.

Child↗
PubMed1984

Two chromosome aberrations in the child of a woman with systemic lupus erythematosus treated with azathioprine and prednisone.

A boy with microcephaly, unusual facial features, micropenis, and growth retardation was born to a 30-year-old woman who took azathioprine and prednisone before and during pregnancy for systemic lupus erythematosus. The child has two apparently de novo chromosomal abnormalities: an apparently balanced translocation between chromosomes 6 and 14 and an interstitial deletion of chromosome 7. The karyotype is 46,XY,del(7)(q21);t(6;14)(q21;q12). Use of azathioprine and prednisone in pregnancy has been associated with intrauterine growth retardation, congenital malformations, and transient chromosome breaks in the blood of newborns. To our knowledge, this is the first report of de novo constitutional chromosome abnormalities in such an infant. We suggest that the assessment of infants born to parents treated with azathioprine should include a chromosome study, even if the infants seem to be normal.

Abnormalities, Drug-Induced↗
PubMed1984

Reproductive outcomes of paracentric inversion carriers: report of a liveborn dicentric recombinant and literature review.

An abnormal infant had a dicentric chromosome 14 with an inverted tandem duplication [46,XY,inv dup(14) (pter----q32.3::q24.2----pter)], thus making him trisomic for the proximal two-thirds of chromosome 14. This abnormality was derived from a maternal paracentric inversion in chromosome 14 [46,XX,inv(14)(q24.2q32.3)]. To our knowledge, this is the first report of a liveborn infant carrying a stable, dicentric product of crossing over within a paracentric inversion loop. A review of the reproductive outcomes of paracentric inversion carriers in the literature suggests that they are at some risk for pregnancy wastage. The risk for liveborn recombinants is small but such births have occurred, at least to female carriers.

Abnormalities, Multiple↗
PubMed1983

Use of repetitive DNA for diagnosis of chromosomal rearrangements.

We have used two repeated DNA fragments (3.4 and 2.1 kb) released from Y chromosome DNA by digestion with the restriction endonuclease Hae III to analyze potential Y chromosome/autosome translocations. Two female patients were studied who each had an abnormal chromosome 22 with extra quinacrine fluorescent material on the short arm. The origin of the 22p+ chromosomes was uncertain after standard cytologic examinations. Analysis of one patient's DNA with the Y-specific repeated DNA probes revealed the presence of both the 3.4 and 2.1kb Y-specific fragments. Thus, in this patient, the additional material was from the Y chromosome. Analysis of the second patient's DNA for Y-specific repeated DNA was negative, indicating that the extra chromosomal segment was not from the long arm of the Y chromosome. These two cases demonstrate that repeated DNA can distinguish between similar appearing aberrant chromosomes and may be useful in karyotypic and prenatal diagnosis.

Adult↗
PubMed1983

Two different structural abnormalities of chromosome 13 in offspring of chromosomally normal parents with two fragile sites.

Two siblings were found with different structural abnormalities involving their maternally inherited chromosome 13. The proband exhibited a ring 13 and a small fragment: 46,XX,r(13) (p11q34), +f, while her clinically normal brother carried a dicentric Robertsonian translocation: 45,XY,dic(13;15) (p11;p11). Both parents had normal karyotypes in peripheral blood and skin fibroblasts. The structural abnormalities of chromosome 13 may be due to an unstable gonadal 13;15 translocation in the mother. In addition, two autosomal fragile sites were segregating in this family. The mother had a fragile (16) (q22) which was inherited by the proband. The father and paternal grandmother possessed a fragile (12)(q13) which was not inherited by either child. The expression of both fragile sites was dependent on culture conditions.

Abnormalities, Multiple↗
PubMed1983

Turner syndrome patients with a ring X chromosome.

A patient with clinical features of Turner syndrome and a 45,X karyotype in repeated blood cultures was re-evaluated when she spontaneously entered puberty. A ring X cell line was found in a small proportion of fibroblasts. A review of 35 previously published ring X cases is presented. All are mosaic, the major cell line in most cases being 45,X. There is wide variation in the frequency with which the abnormalities associated with Turner syndrome are found in these patients. All have short stature. Some are sexually developed and fertile. Cardiovascular anomalies are uncommon. This phenotypic variation may have at least two causes: the size of the deleted portion at each end of the X chromosome, and the relative frequency and distribution of 45,X and 46,X,r(X) cell lines in various body tissues.

Child↗
PubMed1983

Distal monosomy 14 not associated with ring formation.

A 12-year-old boy with congenital heart disease, short stature, mildly dysmorphic facies, and mild intellectual impairment was found to have a de novo terminal deletion (14)(q32.3). Although his phenotype resembles that of six reported patients with a similar breakpoint, his CNS involvement is milder. He appears to be the first reported case of a terminal deletion of chromosome 14 not associated with ring 14 formation. Advanced parental ages and maternal origin of the chromosome with the deletion are noted.

Child↗
PubMed1981

Partial trisomy 6q, due to balanced maternal translocation (6;22) (q21; p13) or (q21; pter).

We report a stillborn infant with partial trisomy 6q who had several major congenital malformations not previously associated with the chromosomal aberration. These included occipital encephalocele, ambiguous genitalia with imperforate anus, omphalocele and unilateral hydronephrosis. The infant's karyotype was 46,XY,-22,der(22),t(6;22)(q21; p13) or (q21;pter)mat. The mother and maternal grandmother are balanced translocation carriers.

Abnormalities, Multiple↗
PubMed1979

Mutational analysis of natural alleles in and affecting the B incompatibility factor of Schizophyllum.

Primary mutations in the alleles of alpha 1 and beta 7 of the B incompatibility factor of Schizophyllum were induced with X rays. An additional mutation unlinked to the B factor and affecting its regulatory function was detected. This mutation is effective in monokaryons with most B-factor specificities. The spectra of induced mutations in different alleles is discussed in reference to a polarity in the expression of the recognition function and the regulatory function by each locus of the B incompatibility factor.

Agaricales↗
PubMed1978

Repair of UV-induced damage in wild-type and mutant strains of Schizophyllum commune.

The basidiomycete fungus Schizophyllum commune was found to have both photo-repair and dark-repair systems for UV-induced damage. Three UV-sensitive mutants were isolated and characterized for ability to repair UV-induced damage in light and dark, and for cross-sensitivity to caffeine and methyl methanesulfonate. Two of the mutants were damaged, to different extents, in their capacity for excision repair; one of these mutants was also probably damaged in post-replication repair. The third mutant was damaged only in post-replication repair.

Caffeine↗