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Biomedical subjects

F Hecht

Publications and source records attributed to F Hecht.

At least 127 records · Page 7Linked to original sources
PubMed1986

Common mechanism of chromosome inversion in B- and T-cell tumors: relevance to lymphoid development.

An inversion of chromosome 14 present in the tumor cells of a patient with childhood acute lymphoblastic leukemia of B-cell lineage was shown to be the result of a site-specific recombination event between an immunoglobulin heavy-chain variable gene and the joining segment of a T-cell receptor alpha chain. This rearrangement resulted in the formation of a hybrid gene, part immunoglobulin and part T-cell receptor. Furthermore, this hybrid gene was transcribed into messenger RNA with a completely open reading frame. Thus, two loci felt to be normally activated at distinct and disparate points in lymphocyte development were unified and expressed in this tumor.

B-Lymphocytes↗
PubMed1986

Chromosome clues to acute leukemia in Down's syndrome.

Surprisingly few cases of Down's syndrome with acute leukemia have been documented by chromosome banding studies of the leukemia cells. We studied a Down's syndrome child with acute myelomonocytic leukemia and found that, including this case, only 24 cases of Down's syndrome and acute leukemia have been reported with chromosome banding analysis. Twenty-three of the patients had a trisomy 21 chromosome complement, whereas, one had a translocation. The types of acute leukemia included acute myeloblastic leukemia, acute myelomonocytic leukemia, acute monoblastic leukemia, acute lymphoblastic leukemia, and erythroleukemia. Only three cases had chromosomes missing from the leukemic cells. Sixteen of the 24 patients had extra chromosomes in their malignant cells. Chromosomes #8 and #21 were extra in six cases each and chromosomes #19 and #22 were extra in four cases each. Chromosome rearrangements were observed in nine cases. Three of the nine cases had partial deletion of the long arm of chromosome #6. Cases of Down's syndrome with acute leukemia need to be reported with high-resolution chromosome banding of the leukemia cells. There is as yet no clear chromosome clue as to the precise basis of the etiologic association between Down's syndrome and acute leukemia.

Acute Disease↗
PubMed1986

The Philadelphia chromosome: a model of cancer and molecular cytogenetics.

Recent developments in molecular biology related to the Ph chromosome lead us to an evaluation of knowledge regarding this chromosome. The molecular advances are related to two cellular oncogenes, c-abl and c-sis, and also to the identification and molecular cloning of specific areas of DNA (e.g., band 22q11), permitting the isolation of a probe specific for the translocation breakpoint domain. In the preponderant number of cases examined, it was found that the breakpoints at 22q11 occur within a limited region of up to 5-6 kb, for which the term "breakpoint cluster region" (bcr) has been suggested. In contrast, breaks at 9q34 seem to occur within a much larger region at the molecular level. Yet to be established is the exact genetic composition of the bcr and a determination as to whether or not the breaks leading to the disease occur preferentially within specific areas. In spite of this level of knowledge, we do not understand how the Ph chromosome participates in CML. If Ph-positive CML is ultimately associated with a cascade of gene activations, the unraveling of their nature and chronology will undoubtedly tell us much of their contribution to the biology of CML, in particular, and to neoplasia, in general. In this respect, the rather clear description of CML in cytogenetic, clinical, and laboratory terms, the relatively long chronic phase of the disease, and the association of the blastic phase with nonrandom chromosome changes (at least in the initial phases of the disease) make Ph-positive CML an excellent candidate for a model for the study of molecular events in human neoplasia.

Chromosome Banding↗
PubMed1986

Chromosome change in transitional cell carcinoma of ureter.

Primary transitional cell carcinoma of the ureter is a relatively rare cancer. A case of transitional cell carcinoma of the mid-portion of the ureter in an adult male has been studied cytogenetically and has been found to have trisomy of chromosome #7 (+7) as the only karyotypic abnormality. In an earlier instance of transitional cell carcinoma of the ureter, we observed trisomy 7 together with monosomy 9 and an isochromosome for 5p. The relation of this observation to the cytogenetic findings in transitional cell carcinoma of the bladder is discussed and their possible significance evaluated. The rarity of the cytogenetic findings in these tumors is stressed, as is the possible role played by the chromosomal change in this condition, which may possibly involve the c-erb B oncogene.

Carcinoma, Transitional Cell↗
PubMed1986

Telomeric fusion in pre-T-cell acute lymphoblastic leukemia.

Telomeric fusion, a rare phenomenon, was observed in malignant cells from the peripheral blood of an 18-year-old male with rapidly progressive pre-T-cell acute lymphoblastic leukemia (ALL). Only two comparable cases, both with B-cell ALL, have been reported with telomeric fusion in neoplasia. All of the leukemic cells examined from our patient had two chromosome abnormalities consisting of partial triplication (trp) of chromosome 2 and a derivative chromosome 3. Approximately a third of the leukemic cells showed in addition telomere-telomere fusions. These involved the telomeric regions of 1p, 2p, 4q, 5q, 7q, 10q, 11q, 12p, 15p, 21p, and Xq and 3p of the derivative (3). The findings in this case suggest that telomeric fusion may function as a mechanism for the development of chromosome rearrangements that may play a role, albeit rarely, in human neoplasia.

Adolescent↗
PubMed1986

Chromosomes in kidney, ureter, and bladder cancer.

Although Wilms tumor has been a favored subject for cytogenetic investigation, little is known about chromosomes in adult urinary tract cancers. For this reason, we excluded Wilms' tumor and studied a series of 32 adult urinary tract tumors. Nineteen tumors had detectable autosomal abnormalities. Each of ten renal tumors (consisting of eight renal cell and two transitional cell carcinomas) had three or more chromosome abnormalities. Two candidates for primary chromosome changes in renal cancer are rearrangement of 3p14 and an unbalanced translocation with breakpoints of 5q13 and 14q22. Trisomy 20 is a frequent secondary change. Other nonrandom changes in renal cancer are rearrangements of 1q and +7, -8, -9, -14, -15, +16, and deletions of 17p. Eight bladder and a ureter tumor were all transitional cell carcinomas. Two bladder and the ureter tumor had only one detectable abnormality: deletions of 10q24 and 21q22 and +7, respectively. Other nonrandom bladder changes were -9, +13, +15, and +20. From a cytogenetic standpoint, adult urinary tract tumors appear to be chromosomally complex but critical consistencies are emerging.

Adult↗
PubMed1986

Genetic control over fragile X chromosome expression.

The cytogenetic expression of fragile sites is highly variable. Sites are seen in differing proportions of cells. To determine if part of this variability is genetic, the proportions of lymphocytes manifesting the fragile X were examined in a large cohort of males with the fragile X chromosome. The number of fragile X cells was solely determined by genetic factors: the heritability as determined from the correlation between brothers as well as between cousins was 99.6% and 94.4%, respectively, as compared with 0% in unrelated males with the fragile X. This is consistent with pure genetic determination without any environmental influence over the expression of the fragile X chromosome in males.

Alleles↗
PubMed1986

Population cytogenetics of autosomal fragile sites.

The present investigation deals with a population chromosomal survey for autosomal fragile sites under conditions of folate deprivation in 405 mental retardates. A total of 13 ascertainments of folate sensitive autosomal fragile sites is observed, of which 10q23 fragility appears to be the most frequent. Further cytogenetic studies of normal and retarded individuals are required to help elucidate the possible phenotypic effect of these autosomal sites and mental retardation.

Chromosome Fragile Sites↗
PubMed1986

Congenital cutis laxa with retardation of growth and motor development: a recessive disorder of connective tissue with male lethality.

A syndrome of cutis laxa, ligamentous laxity and delayed motor development has been reported in 13 children. All are girls. Four are from Saudi Arabia. Another Saudi Arabian girl, the product of a consanguineous union, is described with intrauterine growth retardation, delayed closure of the anterior fontanel, slow motor development, cutis laxa and ligamentous laxity. The syndrome appears to be an autosomal recessive disorder of connective tissue, with male lethality.

Consanguinity↗