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Biomedical subjects

H F Mark

Publications and source records attributed to H F Mark.

At least 91 records · Page 5Linked to original sources
PubMed1993

A novel, convenient, and inexpensive approach for deriving ISCN (1985) relative lengths: validation by a morphometric study of 100 karyotyped metaphase cells.

The present study stemmed from a need for a rapid means of deriving reproducible chromosome measurements. An internal set of standards can serve as the basis for routine, easy, and reliable morphometric comparisons. In this study, a total of 100 karyotyped metaphases were analyzed using the Nestler Run-Mate, a computerized curvilinear measuring tool. The null hypothesis tested was that there are no significant differences between chromosomal relative-length values obtained via this previously untested approach and those cited in ISCN (1985). The results indicate that this new method is not only feasible and adequate but has advantage over the conventional approach, which requires the use of a projector and screen to measure chromosomes in unkaryotyped metaphase spreads; further, it is less expensive and easier than using computerized digitizing tablets, a conclusion supported by time-and-effort measurements. Immediately obvious applications include routine use in clinical cytogenetics laboratories, as well as for fractional length estimations in fluorescent in situ hybridization studies performed in research laboratories that do not have access to expensive automated instrumentation.

Chromosomes↗
PubMed1993

Analysis of the growth properties and physical state of the human papillomavirus type 16 genome in cell lines derived from primary cervical tumors.

We have established three cell lines from keratinizing and nonkeratinizing cervical carcinomas with distinct growth properties in vitro and in vivo. Each cell line contained human papillomavirus type 16 DNA sequences, but the lines differed in the physical state of the viral genome present in the cells. A high copy number of episomal human papillomavirus type 16 DNA sequences was detected in the TC-140 line derived from a keratinizing cervical cancer. This cell line had an aneuploid karyotype, did not grow in soft agarose, and formed benign cystlike nodules in nude mice, similar in morphology to well-differentiated areas of the primary tumor. Only integrated human papillomavirus type 16 sequences were detected in the TC-146A and TC-146B lines established from a nonkeratinizing large-cell cervical carcinoma. These cell lines exhibited reduced sensitivity to transforming growth factor-beta 1 and produced invasive, but not progressively growing, tumors in nude mice. These cell lines should complement existing in vitro models of cervical carcinogenesis and provide useful tools for understanding the importance of virus integration in the transformation process as well as the cellular and molecular basis for tumor progression.

Adult↗
PubMed1992

Construction and characterization of radiation hybrids for chromosome 9, and their use in mapping cosmid probes on the chromosome.

Radiation hybrids were produced from a monochromosomal microcell hybrid (PK87-9) which contains only human chromosome 9 with an inserted marker on 9p. Doses of radiation ranging from 1000 to 8000 rads were used to produce a series of hybrids with different size fragments of human chromosome 9. The inserted dominant selectable marker was used to select for hybrids that preferentially maintain fragments of 9p. A panel of 53 radiation hybrids were characterized for 17 chromosome 9 markers. In addition, 17 hybrids were analyzed by fluorescent in situ hybridization (FISH). Hybrids were produced with breaks on both 9p and 9q, many of which appear to contain a single fragment of human chromosome 9. These hybrid cell lines were used to regionally localize 31 cosmids isolated from a chromosome 9 cosmid library. Six cosmids were mapped to intervals on 9p, six cosmids mapped to the centromeric region of the chromosome, and 19 mapped to 9q.

Animals↗
PubMed1991

Schistosoma mansoni: two-dimensional gel electrophoretic analysis of antigens uniquely immunoreactive with protective rat serum.

Candidate vaccine antigens are defined by their differential immunoreactivity with antisera which are distinguishable by their capacity to confer passive resistance to infection. This "contrasting antisera" immunoassay has been successfully used in previous analyses of 4-week-old worm biosynthetically radiolabeled Schistosoma mansoni proteins to identify potentially protective antigens. Twice-infected Fischer (F-2x) and Wistar-Furth (W-2x) rat sera were the sources of protective and non-protective antibody, respectively. We have extended our original analysis by applying two-dimensional gel electrophoresis to resolve total and immunoreactive soluble proteins of the 4-week worms. Total proteins were characterized by silver staining and autoradiography. Radiolabeled protein antigens immunoprecipitated by F-2x and W-2x antisera were compared, and several were shown to be uniquely reactive with the protective immune serum. In a companion molecular approach to clone the candidate vaccine antigens, screening of a lambda gt11 adult S. mansoni cDNA expression library by the contrasting antisera assay has identified a clone (lambda 40) producing a fusion protein with epitopes uniquely reactive with F-2x. A rabbit antiserum to the lambda 40 fusion protein (anti-FP40) reacted with radiolabeled worm proteins in the 20-kDa size range. By 2D gel electrophoretic analysis, we can now demonstrate that anti-FP40 specifically immunoprecipitates most of the members of a multicomponent protein antigen subset 18-22 kDa in Mr, focusing over a pI range of 5.3-5.8, and recognized uniquely by F-2x.

Animals↗
PubMed1977

Centromeric effect on the degree of nonrandom disjunction in the female Drosophila melanogaster.

From crosses of females possessing a heteromorphic X-chromosome bivalent, FR1/+, the shorter crossover products were recovered on the average more frequently than the longer reciprocals as predicted by Novitski's (1951) hypothesis of nonrandom disjunction (NRD). The present study stemmed from an unexpected result of these crosses. Evidence for a centromeric effect on NRD was obtained, suggested by a negative correlation between the degree of NRD, c, and the distance between the region of exchange and the centromere as inferred from SET's (single exchange tetrads). Studies on sex chromosome systems other than FR1 confirmed these results. An analogous centromeric effect on preferential segregation had been clearly demonstrated in maize (Kikudome 1958, 1959; Rhoades and Dempsey 1966). However, prior to the present investigation, no such effect of the centromere on NRD in Drosophila had been described, although reanalysis of part of the data of Novitski (1951) and Novitski and Sandler (1956) suggests some evidence of a seriation of increasing c values extending from the most distal region of the chromosome toward the centromere. A suggestion that the effect in Drosophila may be related in some way to the time required for chiasma terminalization, i.e., those terminalizing earlier (distally located crossovers) permitting more random disjunction of the chromatids from the asymmetric dyad and those terminalizing later, progressively less random, is considered and rejected since in general the expected pattern of c values for the various double exchange tetrads (DET's) is inconsistent with that prediction and provides evidence suggesting the possibility of reversals, in part, of c values obtained for SET's.

Animals↗
PubMed1977

Reproduction in a woman with low percentage t(21q21q) mosaicism.

The birth of a child is described with Down syndrome followed by the conception of a fetus bearing the t(21q21q) chromosome in 100% of their cells in a women mosiac for the translocation in less than 10% of 2 of her examined tissues and in none of the cells in her peripheral blood. Various hypotheses for explaining the above findings are discussed. The importance of examining as many parental tissues as possible for the detection of low percentage mosiacism is stressed.

Adult↗
PubMed1976

Further notes on the behavior of induced asymmetric dyads in the male of Drosophila melanogaster.

The present study confirms the findings of Zimmering and Bendbow [28], that there is preferential recovery of the shorter elements of asymmetric dyads following induced exchanges in irradiated T(2;-3)bwv4 males. Deletion studies giving rough estimates of contaminations of phenotypic crossovers by deletions (or point mutations) have now provided more accurate estimates of the degrees of non-randomness (c) in the regions studied. The significance of the V4 studies and their implications on the mechanisms of meiotic drive are discussed.

Animals↗
PubMedDate not supplied

Children exposed to chronic contamination after the Chernobyl accident: cytogenetic and radiotoxicological analyses.

In this study, we describe cytogenetic studies of lymphocytes obtained from children who were exposed after the Chernobyl accident to low doses of ionizing radiation. We sought to determine possible chromosomal damage relative to internal contamination, as measured by whole-body counter and urine radiotoxicological analyses. The study was performed during a 1-mo period on the peripheral blood of children hosted in Italy, but who resided in contaminated regions of the Russian Federation and Belarus. We used conventional cytogenetics to detect chromosomal aberrations. In some cases, we also used "chromosome painting" to look for stable aberrations. There were more acentric fragments in subjects than in controls; a few chromosome and chromatid breaks werefound in the subjects, but this finding did not differ significantly between subjects and controls.

Body Burden↗
PubMedDate not supplied

HER-2/neu gene amplification in stages I-IV breast cancer detected by fluorescent in situ hybridization.

PURPOSE: Approximately 25-30% of breast and ovarian carcinomas have amplification of the HER-2/neu oncogene. The aim of the present study was to focus on HER-2/neu gene amplification in different clinical stages of breast cancer in order to (1) determine if fluorescent in situ hybridization (FISH) can be used to detect HER-2/neu gene amplification in different clinical stages of breast cancer, (2) establish whether HER-2/neu gene amplification characterizes a subset of breast cancer in each of these stages, and (3) determine whether a trend for correlation of amplification with the clinical stage of the disease can be detected using the FISH technology. METHODS: A total of 40 specimens of formalin-fixed, paraffin-embedded breast cancer tissues were analyzed cytogenetically, in a blinded fashion, for HER-2/neu gene amplification using FISH and the Vysis LSI HER-2/neu Orange and CEP 17 Green DNA dual color probe. The criterion for "high amplification" was an amplification ratio of >4.0, that for "moderate amplification" a ratio between 2.1 and 4.0, and that for "low amplification" a ratio of 1.5-2.0. RESULTS: Using a cutoff point of > or =1.5, the overall frequency of HER-2/neu gene amplification among stage I tumors was 30% (3 out of 10). Of these, one-third (1 out of 3) showed low amplification, one-third (1 out of 3) were moderately amplified, and one-third (1 out of 3) were highly amplified. The overall frequency of HER-2/neu gene amplification among stage II tumors was 0% (0 out of 10). The overall frequency of HER-2/neu gene amplification among stage III tumors was 10% (1 out of 10). The sole tumor found positive was classified as moderately amplified by our criteria. The overall frequency of HER-2/neu gene amplification among stage IV tumors was 50% (5 out of 10). Four of the 5 tumors found positive were highly amplified. The overall frequency of gene amplification in the 40 cases studied was 22.5% (9 out of 40 tumors studied). CONCLUSION: Although a linear correlation between HER-2/neu amplification and clinical stage cannot be established at this time, it is interesting to note that when stages I and II, and when stages III and IV are combined, respectively, the latter category has a higher amplification frequency than the former. Furthermore, stage IV has the highest frequency (5 out of 10) of HER-2/neu gene amplification than all three lower stages combined (4 out of 30). This is no doubt due to the high frequency of gene amplification observed in stage IV tumors, which, interestingly, also demonstrate high level amplification of HER-2/neu gene copy numbers. Although the biologic and clinical basis for gene amplification is not clear, given the observation that the most aggressive disease stage is associated with the highest frequency of gene amplification and the most high level amplification, further exploration of HER-2/neu as a prognostic marker of poor outcome using FISH is warranted.

Breast Neoplasms↗
PubMedDate not supplied

Trisomy 9 in a patient with secondary acute myelogenous leukemia detected by fluorescent in situ hybridization.

Fluorescent in situ hybridization (FISH) is a molecular cytogenetic technique that is playing an increasingly important role for augmenting the findings of conventional cytogenetics. Here we present the case history of a patient with the clinical diagnosis of secondary acute myelogenous leukemia whose bone marrow cells were found to be hyperdiploid with an extra C group chromosome in a less than optimal preparation. By using FISH the extra chromosome was unequivocally determined to be a chromosome 9. The detection of trisomy 9 in this patient underscores the utility of FISH as an adjunct to GTG banding in the routine diagnosis and management of leukemic patients.

Adult↗
PubMedDate not supplied

Undifferentiated small cell hepatoblastoma with a unique chromosomal translocation: a case report.

Cytogenetic studies of pediatric tumors have revealed a number of reproducible karyotypic abnormalities, including del(p13) found in aniridia-Wilms' tumor association, t(8;14) in Burkitt's lymphoma, and t(11;22) in Ewing's sarcoma. To date, no consistent cytogenetic abnormality has been reported in association with hepatoblastoma. We report the case of a 7-month-old male infant with the undifferentiated small cell variant of hepatoblastoma. Immunohistochemistry revealed reactivity with antibodies to cytokeratin and vimentin throughout the tumor. Alpha-fetoprotein, neuron-specific enolase, and S100 stains were negative. Chromosomal analysis of metaphase cells from a culture of tumor tissue revealed a translocation of most of the long arm of chromosome 22 to the distal long arm of chromosome 10.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Assessment of sex chromosome composition using fluorescent in situ hybridization as an adjunct to GTG-banding.

Fluorescent in situ hybridization (FISH) using dual color X chromosome- and Y chromosome-specific probes was employed to assess further the sex chromosome copy number in cells of a phenotypic female patient with hypergonadotropic hypogonadism, primary amenorrhea and growth retardation. The GTG-banding analysis of peripheral blood lymphocytes had revealed the presence of predominantly 46,XY cells. A FISH analysis, undertaken to assess further the contribution of a minor cell line, yielded frequencies of 87% cells with the 46,XY constitution and 9% with the 45,X constitution. To establish unequivocally the presence of mosaicism, a skin biopsy was obtained for fibroblast culture, which further corroborated the results of the peripheral blood study. Fluorescent in situ hybridization analysis revealed 74% of the cells to be 46,XY and 12% to be 45,X. The unequivocal presence of XY cells puts the patient at risk for neoplastic transformation of the gonads. Laparoscopy and surgical removal of the patient's presumptive streak gonads were therefore undertaken. Cytogenetic results derived from the gonadal tissues further strengthened findings of previous cytogenetic analyses. It is our experience that FISH is a useful adjunct to established cytogenetic techniques in the management and monitoring of patients similar to the proband described in this study.

Adolescent↗
PubMedDate not supplied

Fluorescent in situ hybridization assessment of chromosome copy number in gestational trophoblastic disease.

The concurrence of congenital trisomy 8 mosaicism and gestational trophoblastic disease in a forty-two-year-old Gravida IV, Para IV female has been described. In contrast to other cases in the literature, this patient had no additional confounding chromosomal abnormalities other than trisomy 8. To the best of our knowledge, this was the only reported case of constitutional trisomy 8 mosaicism associated with gestational trophoblastic disease, a rare gynecological disease entity in and by itself. The present report describes fluorescent in situ hybridization (FISH) studies for assessing chromosome 8 copy number on various patient tissues. The results of the FISH studies are compared with each other and with the original cytogenetic studies. It is concluded that the overall frequency of trisomy 8 cells is lower in the FISH studies using archival material than in the original conventional cytogenetic studies. This is true for the uterus and lung tissues with a metastatic tumor. The possible reasons for the somewhat different frequencies found between conventional cytogenetics via GTG-banding and interphase cytogenetics via FISH are discussed.

Chromosomes, Human, Pair 8↗
PubMedDate not supplied

Fluorescent in situ hybridization for assessing the proportion of cells with trisomy 4 in a patient with acute non-lymphoblastic leukemia.

A case of acute non-lymphoblastic leukemia is described in which fluorescent in situ hybridization (FISH) helped to resolve initially conflicting conventional cytogenetic results. Identification and assessment of the proportion of cells exhibiting trisomy of chromosome 4 in the patient's bone marrow were made using a probe which hybridizes to the centromeric region of chromosome 4. These FISH results were consistent with our retrospective GTG-banded analysis but differed from another study conducted elsewhere. Factors such as culture conditions and duration of culture which may have influenced the proportion of leukemic to nonleukemic cells are discussed. Fluorescent in situ hybridization is a powerful adjunct to conventional cytogenetic analysis and may prove to be a useful tool for monitoring minimal residual disease in this patient.

Adult↗
PubMedDate not supplied

Cytogenetic characterization of three cell lines derived from primary cervical tumors.

Braun et al established three cell lines from keratinizing and nonkeratinizing cervical carcinomas. These cell lines were subsequently analyzed for growth properties and physical state of the human papillomavirus type 16 genome. It was found that these cell lines have distinct growth properties in vitro and in vivo. Furthermore, they differ in the physical state of the viral genome. TC-140/7, derived from a keratinizing cervical tumor, contains primarily human papillomavirus type 16 in the episomal state. Both TC-146A and TC-146B, derived from a nonkeratinizing large-cell cervical carcinoma, contain exclusively human papillomavirus type 16 in the integrated state. The chromosomes of these three cell lines were characterized in the present study using GTG-banding analysis. The most striking chromosomal abnormalities noted in the TC-140/7 cell line were the presence of a small metacentric consistent with the morphology of an i(12p) or i(5p), an isochromosome 8q and multiple copies of chromosome 9. For TC-146A, the most notable chromosomal abnormalities were in the presence of a derivative chromosome 7 with additional material present on its long arm, an i(8q) and derivative chromosome 19's. For cell line 146B, the most notable chromosomal abnormalities were found to be a marker resembling a derivative X chromosome, a derivative chromosome 7 with additional material on its long arms, an i(8q), an i(16q) and one or more copies of a marker with morphology resembling i(17q). Fluorescent in situ hybridization experiments using select probes further corroborate the results of the conventional cytogenetic studies.

Adult↗
PubMedDate not supplied

A practical cytogenetic protocol for in vitro cytotoxicity and genotoxicity testing.

In vitro cytogenetics has been established as a valid method for evaluating the genotoxic potential of chemical agents. Armstrong et al have described a simple, quantitative approach to in vitro cytotoxicity and genotoxicity testing by using Chinese hamster ovary (CHO) cells. This approach can also be sensitive and repeatable in an inter-laboratory setting, a prerequisite for routine testing of compounds suspected of having genotoxic properties. In the present study, cytotoxicity was evaluated by the parameter of mitotic index (MI). Genotoxicity is measured by the chromosome aberration (Abs) assay as described by Armstrong et al using CHO cells. The basic analytic principles proposed were extended to include human lymphocytes. Sister chromatid exchange (SCE) analysis was used to establish an additional endpoint. Mitomycin C (MMC), an established clastogen, was used as the model compound for protocol validation. Dose response curves for MI and Abs in CHO cells were found to be consistent with those reported by Armstrong et al. Results from our extended study on lymphocytes and using SCE analysis were analogous. Our experience is that this standardized approach is indeed sensitive and reliable and can serve as a basis for an inter-laboratory testing program.

Animals↗