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Biomedical subjects

H F Mark

Publications and source records attributed to H F Mark.

At least 73 records · Page 4Linked to original sources
PubMed1996

A multimodal approach for diagnosing patients with acute promyelocytic leukaemia.

A practical and efficient multi-modal protocol for processing specimens for patients referred with a question of acute promyelocytic leukaemia (APL) is described. The initial analysis comprises haematological evaluation of the bone marrow and peripheral blood smears using Romanowsky-stained slides. Concomitantly, a sample is processed for direct preparation as well as 1- and 2-day unstimulated cultures using conventional cytogenetic techniques. Communication between the cytogenetic and haematological laboratories is of critical importance so that the optimal conditions for culture (i.e. longer term versus unstimulated overnight and direct preparations) for the cytogenetic detection of chromosome rearrangements can be selected. The likelihood of detecting the characteristic translocation of APL, t(15;17), is enhanced in a longer term culture versus unstimulated overnight and direct preparations. Fluorescent in situ hybridization (FISH), utilized as an adjunct to GTG-banding, was found to be a powerful technique for detecting the t(15;17), especially where the GTG-banded preparation was of suboptimal quality. Results of five recent representative cases of APL are described to illustrate a practical approach which can be adapted by any clinical pathology laboratory.

Adolescent↗
PubMed1996

Fluorescent in situ hybridization assessment of chromosome copy number in buccal mucosal cells.

Sex chromatin (Barr body) analysis of buccal mucosal cells has been recognized for many years as an inexpensive, noninvasive and rapid means of sex determination. The conventional Barr body analysis using Papanicolaou stain was discontinued as a routine test because of its lack of reliability and its inability to detect mosaicism and other chromosomal abnormalities. With the advent of recombinant DNA technology and the availability of molecular probes, however, the value of this simple albeit obsolete test should be re-evaluated. The results of the authors' experience in optimizing a fluorescent in situ hybridization (FISH) assay on buccal mucosal cells are described. The utility and potential of this assay are explored and discussed.

Evaluation Studies as Topic↗
PubMed1996

Issues in the genetic assessment of predispositions for familial breast and ovarian cancer.

A rapid development in technology has enabled predictive testing for cancer suceptibility genes, such as BRCA1 and BRCA2. Already biotechnology companies and a number of university-based researchers are establishing service laboratories for the analysis of cancer predispositions. It is critical that high standards be established and maintained when conducting DNA testing, which should be performed in a research setting with proper Institutional Review Board approval. A cancer risk assessment programme should include the involvement of various experts in genetics, oncology, psychiatry and counselling. The legal, ethical and social issues involved in screening and testing for cancer predisposition genes are complex. Genetic counselling of subjects undergoing testing is needed to inform them of the potential risks as well as the potential benefits associated with presymptomatic testing.

Breast Neoplasms↗
PubMed1996

The impact of managed care on genetic testing laboratories in the United States.

The traditional activities of clinical genetics programmes have focused on service, education and research. These activities have been funded on a fee-for-service basis often supplemented by service and research grants from private and government sources. Developing changes in health care financing threaten this approach to funding of genetics programmes in general and of genetics laboratories in particular. The evolution of managed health care requires new strategies for delivery of clinical and laboratory services with an emphasis on adaptability. Strategies may include development of alliances among related laboratories, subcontracting with large, multiservice laboratories and developing formalized marketing plans.

Clinical Laboratory Techniques↗
PubMed1995

Cytotoxicity and genotoxicity of wood drying condensate from Southern Yellow Pine: an in vitro study.

We tested condensates from Southern Yellow Pine for potential cytotoxicity and genotoxicity in CHO-WBL and human peripheral blood lymphocytes (PBL) in the absence of S-9 activation. Cytotoxicity was evaluated by the Trypan blue exclusion assay, mitotic index (MI) and proliferative rate index (PRI). Genotoxicity was measured by the chromosome aberration (CA) assay and sister chromatid exchange (SCE) analysis. Both cytotoxic and genotoxic effects were observed. Laboratory-generated Southern Yellow Pine condensate reduced the viability of CHO-WBL cells. The number of viable cells was roughly inversely proportional to dosage over a range of 100% to 31% in treated groups, in both experiments, as compared to 2.6 x 10(5) (100%) in the control. The MI data in both CHO cells and PBL also showed an inverse correlation. The highest scorable dose limited by toxicity was determined to be 1 ml of Southern Yellow Pine condensate in 10 ml total of medium. Lastly, a dose response curve was observed in CHO cells, as well as in PBL, using the CA assay and also with the SCE analysis. The present findings corroborate the results from Ames testing and represent the only information currently available on the genotoxic potential of these chemicals.

Animals↗
PubMed1995

Towards the development of a fluorescent in situ hybridization based genotoxicologic assay for aneuploidy detection in sperm.

Fluorescent in situ hybridization (FISH) is a molecular cytogenetic technique which allows an analysis of chromosome copy number in interphase cells. The cytological examination of spermatozoa is routinely performed as part of semen analysis. While this analysis is only a component of the evaluation of an infertile male, the aetiology of many cases of infertility remains unknown. FISH on semen smears can yield information on chromosome-specific aneuploidy due to constitutional and acquired chromosomal abnormalities as found with cancer or exposure to genotoxic substances. The ability to analyse germ cells directly is a useful adjunct to GTG-banding analysis of meiotic chromosomes, an invasive and extremely labour-intensive procedure. The work of 2 years in developing and optimizing a FISH-based assay in routinely processed semen smears is described.

Aneuploidy↗
PubMed1995

Eastern white pine wood-drying condensate induced cytotoxicity and genotoxicity in human peripheral blood lymphocytes in vitro.

Condensate from eastern white pine, one of the commercially most important species of tree in the northeastern United States, was treated for potential cytotoxicity and genotoxicity in human peripheral blood lymphocytes in the absence of S-9 activation. Cytotoxicity was evaluated by mitotic index (MI) determination and proliferative rate index. Genotoxicity was measured by the chromosome aberration (CA) assay and sister chromatid exchange (SCE) analysis. Both cytotoxic and genotoxic effects were observed with laboratory-generated eastern white pine condensate. The MI data showed an inverse correlation between the MI and treatment dosage. A dose response curve was observed using the CA assay and also with the SCE analysis. The present findings thus corroborate the results from Ames testing and represent the only information currently available on the cytotoxic and genotoxic potential of these chemicals.

Cell Division↗
PubMed1995

A study of induced genotoxicity in MCF-7 cells.

Following upon earlier work the response of MCF-7 breast cancer cells to mitomycin C, a known genotoxicant, was examined. This previous research has yielded a baseline of chromosome aberrations in human peripheral blood lymphocytes from which comparisons can now be made. Results of genotoxicity testing conducted with the same protocol yielded a significantly increased level of chromosome aberrations in MCF-7 cells than in normal human peripheral blood lymphocytes. Dose response curves are presented. Although these results need to be confirmed and extended, the hypothesis is proposed that the present findings are simply another manifestation of the genetic instability inherent in these cancer cells. This seems to be the only known published study of breast cancer cells addressing this issue using the techniques of cytogenetics.

Adenocarcinoma↗
PubMed1995

Red oak condensate: its apparent lack of cytotoxic and genotoxic effects as compared with three other wood-drying condensates.

A major activity of the lumber industry is the kiln-drying of wood. In order to ascertain whether wood-drying condensates pose a possible environmental hazard, the cytotoxicity and genotoxicity of these condensates in vitro, were tested using an assay validated using Chinese hamster ovary (CHO) cells and a known genotoxicant, mitomycin C. Subsequently, the assay was developed for the human peripheral blood lymphocyte (HPBL) system, as it was felt that results derived from human cells would reflect the situation more closely in vivo. Condensates from Southern yellow pine, Eastern white pine and Douglas fir trees were tested in CHO and HPBL systems and have demonstrated cytotoxic and genotoxic effects in vitro, as reported elsewhere. Red oak condensate has also been tested using the HPBL system. Thus far, results are consistent with the hypothesis that there is no difference between the cytotoxic and genotoxic effects of treated cells versus controls. This finding indicates either that the condensate of red oak poses no appreciable genetic hazard as measured by cytotoxicity and genotoxicity assays, or that the condensate has lost its potency with time and storage; both of these possibilities have important environmental implications.

Air Pollutants↗
PubMed1994

Fluorescent in situ hybridization in routinely processed bone marrow aspirate clot and core biopsy sections.

Fluorescent in situ hybridization (FISH) is a technique which complements conventional cytogenetic banding analysis by allowing the evaluation of cells in interphase as well as metaphase. This technique has been used to study air-dried peripheral blood and bone marrow aspirate smears. We have applied the FISH technique to study routinely processed sections of bone marrow aspirate clot and decalcified core biopsy specimens, fixed in either formalin or B5 and embedded in paraffin. We evaluated 28 specimens (8 aspirate clot and 20 core biopsy sections) for chromosome 8 copy number, studied previously by conventional cytogenetics, and found the following distribution: 15 with disomy, 11 with trisomy, and 2 with tetrasomy. Using a chromosome 8 alpha-satellite probe, we detected fluorescent hybridization signals in 18 of 28 specimens (64%); 6 of 8 (75%) aspirate clot sections, and 12 of 20 (60%) core biopsy sections. Ten of 13 (77%) B5-fixed and 8 of 15 (53%) formalin-fixed specimens had hybridizing signals. Specimen age was a significant factor; 10 of 11 (91%) specimens processed within the last 6 months showed signals, in contrast with 8 of 17 (47%) specimens older than 6 months. In the positive specimens, 200 cells were analyzed in areas where individual cells could be identified. In the disomic specimens, two signals per cell were seen in 34 to 66% of the cells. Rare cells (0-2%) with three signals were detected. In the trisomic specimens, three signals per cell were seen in 19 to 46% of the cells. In the tetrasomic specimens, four signals per cell were seen in 15 to 25% of the cells. We conclude that the FISH technique may be useful in the detection of numerical chromosomal abnormalities such as trisomy and tetrasomy 8 in routinely processed bone marrow aspirate clot and decalcified core biopsy sections.

Biopsy, Needle↗
PubMed1993

A study of homologous chromosomes using a morphometric approach.

A previous study of 100 karyotyped metaphase cells has demonstrated the utility of a graphic arts tool in deriving chromosome measurements for relative length determination. In the present study we utilize this same approach to address the question: "What are the average differences in relative lengths between apparently normal homologous chromosomes?" Normal standards derived from this study will be useful for testing specific hypotheses involving heteromorphic differences between homologs. No such data on normal controls could readily be found in either An International System for Human Cytogenetic Nomenclature (1985) or elsewhere.

Chromosomes↗