Biomedical subjects
F Hecht
Publications and source records attributed to F Hecht.
Aneuploidy in recurrent spontaneous aborters: the tendency to parental nondisjunction.
To test the hypothesis that parental aneuploidy, particularly involving sex chromosomes, indicates an increased risk of meiotic nondisjunction, we analyzed chromosome numbers from 283 parents who had had 2 or more spontaneous abortions and, if they had children, no abnormal offspring. A sample of 15 lymphocyte metaphases was examined per individual for a total of 4,245 metaphases. Two or more cells with the same abnormal chromosome complement were found in 19 individuals: 4 males with a minor number of 45,X cells and 15 females with minor numbers of 45,X and/or 47,XXX cells (p less than 0.001). The most logical explanation is that mitosis may, in part, reflect meiosis. This group of parents appears predisposed to chromosome errors in meiosis leading to recurrent spontaneous abortion.
Detection of the fragile X chromosome and other fragile sites.
To assist in cell sample size selection and detect the fragile X chromosome, statistical tables have been presented. A comparable approach had been suggested earlier for the diagnosis of chromosome mosaicism. The cytologic detection of the fragile X or any fragile site is simply a special case in the detection of mosaicism. Minimum numbers of metaphases are recommended for fragile X analysis to have 95% confidence that the fragile X is not manifest in a given proportion of cells and similar recommendations apply to all other fragile sites.
Fragile sites and chromosome breakpoints in constitutional rearrangements I. Amniocentesis.
Since fragile sites may conceivably predispose to chromosome breakage and rearrangements in meiosis, we examined the locations of 278 breakpoints leading to chromosome rearrangements detected in amniocenteses. Of the 278 breakpoints, 59 (21%) were observed to be in bands containing fragile sites compared to an expectation of 31 (11%), a highly significant difference (P less than 0.001). The tendency for breakpoints to be in bands with fragile sites was independent of origin of the rearrangement or class of fragile site, consistent with the concept that fragile sites predispose to heritable chromosome rearrangements.
Fragile sites and chromosome breakpoints in constitutional rearrangements II. Spontaneous abortions, stillbirths and newborns.
Certain fragile sites may possibly predispose to chromosome breakage and rearrangements in meiosis. To test this hypothesis, we examined 894 breakpoints found in spontaneous abortions, stillbirths and livebirths of which 165 (18.5%) were in bands with fragile sites. Compared to an expectation of 98 (11%), there was a significant excess of breakpoints in fragile site bands (P less than 0.001). Together with data from amniocenteses, there is now evidence suggesting that certain fragile sites may be prone to fragility in meiosis.
Autosomal fragile sites and cancer.
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Tay-Sachs disease: Part 1. The risk to non-Jews.
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Tay-Sachs disease: Part 2. Model of a fatal, preventable, metabolic, genetic disorder.
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Couples with repeat spontaneous abortions: chromosome abnormalities.
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Prenatal diagnosis of fragile (X) syndrome.
A fragile site (q27) of the X chromosome has been associated with X-linked mental retardation, and the prenatal diagnosis of the fragile (X) syndrome has been shown to be possible. It is suggested that both fluorodeoxyuridine and methotrexate in thymidine-deficient media be used to demonstrate the fragile (X) in cultured amniotic fluid cells. The fetus diagnosed in utero demonstrated the dolichocephaly, large ears, flattened malar area, and large testes characteristic of the fragile (X) syndrome in the newborn period.
Contemporary management of lymphoma: chromosome studies.
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Antibiotics containing trimethoprim and the fragile X chromosome.
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Position effect in translocation (2;8) in acute lymphocytic leukemia with kappa light chain immunoglobulin expression.
We report a correlation between t(2;8) translocation in acute lymphocytic leukemia and kappa light chain immunoglobulin production. Since the kappa chain genes are on chromosome #2, this, as well as data on Burkitt lymphoma, points to the possibility of position effect on the level of gene action. Chromosome #2 in the translocation together with chromosome #8 is concerned with malignancy, while the normal homologous chromosome #2 transcribes kappa chains. This model applies to B cell leukemias and lymphomas with changes in chromosome #2 which will predictably express kappa chains. The model also applies to B-cell malignancies with changes in chromosome #22 which will predictably express lambda chains.
Fibrous histiocytoma cell line: chromosome studies of mouse and man.
A human cell line isolated from a lung metastasis of a malignant fibrous histiocytoma was studied chromosomally. The cell line had a modal chromosome number of 59 with multiple numerical and morphologic chromosome changes and marker chromosomes. A putative clone from this cell line had a modal number of 41 with exclusively acrocentric chromosomes and was clearly not human but mouse in origin.
Complex cytogenetic findings in acute leukemia.
Although certain types of acute nonlymphocytic leukemia (ANLL) are now characterized by specific chromosome translocations, certain other cases of ANLL elude simple cytogenetic classification. We describe here a case of acute myelomonocytic leukemia with a complex and unusual karyotype picture including double minutes, three definite translocations, two other possible translocations, and additional morphologic and numerical chromosome changes. The three definite translocations were t(2;11), t(2;12), and t(5;15), fitting the criteria of major karyotype abnormalities. These complex and unusual chromosome findings may relate to the rapid course of the disease.
Acute myeloblastic leukemia (AML) with t(6;9) (p23;q34): a specific subgroup of AML?
A case of acute myeloblastic leukemia (AML) of M2 type in the FAB classification without Auer bodies in the leukemic cells was shown to have t(6;9)(p23;q34) in the marrow cells. Four hematologically similar cases with identical karyotype changes have been published. We propose, in support of others, that this may constitute a subgroup of AML characterized by a translocation between chromosome #6 and #9.
Adenocarcinoma of the gallbladder: chromosome abnormalities in a genetic form of cancer.
Chromosome studies on gallbladder adenocarcinoma in a Papago Indian woman were performed. These studies revealed a high degree of aneuploidy including multiple instances of missing chromosomes, extra chromosomes, and chromosome rearrangements. Double minute chromosomes and homogeneous staining regions on chromosomes were present in the cancer cells. To our knowledge this is the first report on the cytogenetic analysis of a gallbladder cancer. Chromosome studies on gallbladder cancers will be of unusual interest because of the relatively high frequency of this rare genetic form of cancer in American Indians.
The half chromatid mutation model and bidirectional mutation in incontinentia pigmenti.
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