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H F Mark

Publications and source records attributed to H F Mark.

104 records · Page 6Linked to original sources
PubMedDate not supplied

Combined strategy of conventional cytogenetics, fluorescent in situ hybridization and chromosome morphometry for analysis of parotid gland tumor.

The limiting factors in conventional cytogenetic analysis of cell culture, especially of solid tumors, include insufficient metaphases, overgrowth of abnormal mitotic cells by normal cells, and suboptimal quality of harvesting and banding. Despite the availability of numerous protocols to induce G-banding, as well as Q-, R-, and C-banding, occasions still arise in which the analysis is severely limited by these factors and incomplete conclusions are often drawn as to the precise nature of the chromosomal abnormality, if indeed any can be detected. By adopting a rational approach of (1) close monitoring of cultures and rapid harvesting as soon as it is feasible, and (2) analysis of available metaphases by a combination of the GTG technique, fluorescent in situ hybridization (FISH), and chromosome morphometry using a graphic arts tool, a significant improvement in success rate may be more readily achieved. Here pathological and cytogenetic data are presented of a case of parotid gland carcinoma ex mixed tumor with the karyotype of 46, XX, del(5)(q12), dir ins(8;5)(q12;q12qter), add(12)(p13)/46, XX. This case is utilized to illustrate the importance of application of our combined strategy.

Chromosomes, Human, Pair 12↗
PubMedDate not supplied

Fluorescent in situ hybridization as an adjunct to conventional cytogenetics.

Fluorescent in situ hybridization (FISH) is a molecular cytogenetic technique that exploits the availability of recombinant deoxyribonucleic acid (DNA) technology. In metaphase FISH, a specific nucleic acid sequence (probe) is bound to the homologous segment on a metaphase chromosome in a fixed preparation on a glass slide. The presence of a region-specific DNA sequence in a nondividing cell can be detected using interphase FISH. Interphase cytogenetics via FISH can be performed on fixed cells harvested during a routine culture, on tissue sections and on many cytologic specimens. Specific examples of clinical and research applications are discussed to illustrate the utility of FISH in the detection of constitutional and acquired chromosomal abnormalities.

Cells, Cultured↗
PubMedDate not supplied

Centromere index derivation by a novel and convenient approach.

A previous study has shown the utility of a graphics arts tool in deriving chromosome measurements for relative length determination. It is our hypothesis that the same approach also can be used accurately for centromere index determination. Results based on a study of 50 cells and comparisons with values cited in An International System for Human Cytogenetic Nomenclature (ISCN) are consistent with this hypothesis. Chromosome morphometry is an important adjunct to conventional cytogenetics in suboptimal banded preparations and/or inadequate specimens such as samples from cancer patients.

Centromere↗
PubMedDate not supplied

Douglas-fir: a third wood-drying condensate found to exhibit in vitro cytotoxicity and genotoxicity.

The present study applies the approach described in Mark et al. for the testing of toxic chemicals produced during the drying of Douglas-fir. The genotoxic potential of Douglas-fir condensate has been previously unexplored and is thus an area of appropriate concern to the forest products industry, regulatory, agencies, and the general public. Previous research conducted in this laboratory has identified two wood-drying condensates that yield positive cytotoxic and genotoxic effects. The results of testing Southern yellow pine and Eastern white pine condensates have been reported elsewhere. Douglas-fir condensate, a third wood-drying condensate, was added in vitro in concentrations ranging from 0.1 to 100 microliters/ml to cultures of Chinese Hamster Ovary (CHO-WBL) cells. A dose response curve was observed with this condensate for both cytotoxicity and genotoxicity. The number of viable cells as well as the mitotic index (MI) and proliferative rate index (PRI) varied inversely with dosage. The result of chromosome aberration (Abs) analysis and sister chromatid exchange (SCE) analysis, both cytogenetic measures of genotoxicity, also gave statistically significant results.

Animals↗
PubMedDate not supplied

The frequency of chromosomal abnormalities in patients referred for fragile X analysis.

The present paper summarizes our existing database on chromosomal abnormalities found in patients referred because of a question of the Fragile X Syndrome during the period from January 1, 1990 to June 30, 1995. Cytogenetic results were derived from testing performed at the cytogenetics laboratory at Rhode Island Hospital. All positive fragile X individuals detected among our sample population represent index patients from separate kindreds. Of a total of 327 cases referred for fragile X testing, 10 (3.06 percent) were found to be positive for fragile X by either cytogenetics alone or by both cytogenetics and DNA testing, 12 (3.60 percent) were found to be positive for either a numerical or structural chromosomal abnormality, while 10 (3.06 percent) were found to exhibit a heteromorphism. Positive chromosomal findings included numerical chromosomal abnormalities of the sex chromosomes and autosomes, deletions, and translocations. Heteromorphism mostly involved an increase in the length of heterochromatic regions of certain chromosomes as well as a pericentric inversion of a chromosome 9, usually considered normal variants. It is concluded that chromosomal abnormalities other than fragile X are found with equal and, in some cases, higher frequency than the frequency of fragile X positivity in patients referred for a question of the Fragile X Syndrome. Our figures, consistent with those reported in the literature, underscore the value of routine karyotyping in this population of patients. Except under special circumstances, it is important that GTG-banding analysis be performed so that the entire human genome be examined in addition to scoring for the fragile X mutation on Xq27.3. Especially in view of the recent finding of the relative rarity of this condition, the exclusive use of DNA analysis is not advised.

Chromosome Aberrations↗
PubMedDate not supplied

Wood-drying condensate from Eastern white pine induced cytotoxicity and genotoxicity in vitro.

Eastern white pine is one of the most important commercial species of wood in the Northeast. Condensates extracted from this wood were tested to detect potential cytotoxicity and genotoxicity in Chinese Hamster Ovary (CHO) cells in the absence of S-9 activation. Cytotoxicity was measured 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 Eastern white pine condensate reduced the viability of CHO cells. The number of viable cells was roughly inversely proportional to dosage over a range of 91 percent to 58 percent survival in treated groups as compared to 2.4 x 10(5) viable cells (100 percent) in the control. The mitotic index (MI) data also showed an inverse correlation with dosage. The highest scorable dose limited by toxicity was determined to be 1 ml of Eastern white pine condensate in a total of 10 ml of medium. Lastly, a dose response curve was observed using the CA assay and also with the SCE analysis. The present findings support results obtained from Ames testing of Eastern white pine condensate and also corroborate results derived from human peripheral-blood lymphocytes.

Animals↗
PubMedDate not supplied

Integration of human papillomavirus sequences in cervical tumor cell lines.

The establishment of three cell lines from keratinizing and nonkeratinizing cervical carcinomas was previously reported. These cell lines were analyzed for growth properties in vitro and in vivo. Metaphases prepared from tissue culture of these cell lines were cytogenetically characterized using GTG-banding and fluorescent in situ hybridization (FISH) using chromosome-specific alpha-satellite probes. Although the karyotypes of most cells were extremely complex, nonrandom karyotypic abnormalities could be identified. Molecular data had suggested that TC140, derived from a keratinizing cervical tumor, may contain HPV 16 in the episomal state, while TC146, derived from a nonkeratinizing large-cell cervical carcinoma, contained HPV 16 in the integrated state. Therefore, a fluorescent in situ hybridization study was undertaken using biotinylated HPV 16 DNA as a probe on order to confirm and to corroborate the original molecular study, as FISH is the most direct approach for mapping cellular and viral sequences in mammalian chromosomes. The results previously reported in abstract demonstrated the presence of positive hybridization signals on the long arms of the apparent homologs of a human D-group chromosome in cell line TC146. The results of recently completed experiments clearly indicated that while the predominant state of viral existence in the TC140 cell line was apparently episomal, consistent viral integration was found in the TC146 cell line. Furthermore, where viral sequences of HPV 16 integration were observed in cells of TC146, integration was apparently nonrandom. Fluorescent in situ hybridization using various chromosome-specific alpha-satellite and HPV 16 probes clearly indicated that viral integration occurred nonrandomly and at a specific site on chromosome 13. By chromosome morphometry, the viral integration site was localized to 13q14, also the mapped locus of the retinoblastoma (Rb) tumor suppressor gene.

Chromosome Banding↗
PubMedDate not supplied

Clinical and research issues in breast cancer genetics.

Breast cancer is the most common form of cancer in women in the U.S. The risk factors for developing breast cancer include increasing age, a family history of breast cancer, and the lack of a child by age 30. A substantial fraction of breast cancer, however, occurs in women who have no identifiable risk factors. The diagnosis, pathology, treatment, and presymptomatic testing of cancer susceptibility genes are reviewed. Syndromes with an associated risk of breast cancer are described, such as hereditary breast-ovarian cancer syndrome, Li-Fraumeni syndrome, ataxia telangiectasia, and Cowden's disease. With the localization of the BRCA1 gene to chromosome 17q21 and the BRCA2 gene to chromosome 13q12, issues surrounding breast cancer susceptibility genetic testing are assuming an ever greater measure of importance. The sensitivity and specificity for molecular testing of cancer susceptibility genes, however, have not been well defined. The progress in presymptomatic genetic testing is further hampered by various factors such as the technical difficulty in distinguishing mutations from polymorphisms, the number of different mutations identified thus far and the possibility of false positive and false negative results. Laboratory quality assurance/quality control issues are of paramount importance to avoid misleading interpretations. Many issues surrounding genetic screening and testing, such as insurance and employment discrimination, privacy, and informed consent, are under active debate, and guidelines and standards are under active development. It is therefore important to proceed with caution, so that irreversible harm resulting from data misinterpretation can be avoided.

Breast Neoplasms↗
PubMedDate not supplied

Current applications of molecular cytogenetic technologies.

This review discusses select current applications of fluorescent in situ hybridization (FISH) which may be of utility for the average clinical cytogenetic laboratory. Owing to the large number of men and women affected, the applications chosen to illustrate the use of FISH technology in cancer focus on two diseases: breast cancer and prostate cancer. The applicability of FISH to detect common aneuploidies, such as trisomy 21, trisomy 18, trisomy 13 and the sex chromosome aneuploidies in prenatal diagnosis, is discussed, as well as FISH for the detection of microdeletions and microduplications. Quality assurance/quality control issues and standards and guidelines relating to laboratory practices in molecular cytogenetic testing are reviewed.

Breast Neoplasms↗
PubMedDate not supplied

Fluorescent in situ hybridization analysis of cervical smears. A pilot study of 20 cases.

The Papanicolaou smear has been established as a useful cytological screening tool that has greatly contributed to the reduction of cervical cancer related mortalities. This test, however, cannot reveal underlying genetic damage, i.e., numerical and structural chromosomal abnormalities that may predispose an individual to a future potentially life-threatening cervical neoplasm. An assay that has the ability to detect genetic abnormalities in interphase cervical mucosal cells will be a useful complement to the Papanicolaou smear on cytological preparations. The present project explores such a possibility using the technique of fluorescent in situ hybridization (FISH). The chromosome 8 specific alpha-satellite probe is initially used because of our past experience in the validation of this probe in various cancers. The applicability of this assay, however, is not restricted to the use of this particular probe. Data on our initial pilot study of 20 cases revealed that such an interphase FISH assay is indeed feasible as a potential future screening tool for cervical cancer.

Chromosome Aberrations↗
PubMedDate not supplied

Disappearing trisomy 8 mosaicism.

A case is presented of a patient with disappearing trisomy 8 mosaicism initially thought to have stigmata of the fragile X syndrome. This case is interesting for two reasons. First, it demonstrates the occurrence of "disappearing mosaicism," a phenomenon first described by LaMarche et al, in 1967. Our patient, initially studied in 1991 by two laboratories and found to be mosaic for chromosome 8 trisomy, was apparently normal by both GTG-banding and fluorescent in situ hybridization (FISH) when studied in 1996. Second, this case further underscores the fact that except under special circumstances, it is important that GTG-banding analysis be performed so that the entire human genome be examined in addition to scoring for the fragile X mutation on Xq27.3. In a recent review of the existing database at Rhode Island Hospital on chromosomal abnormalities found in patients referred because of a question of the fragile X syndrome during the period from January 1, 1990 to June 30, 1995, it was found that the frequency of other chromosomal abnormalities in patients referred because of a question of fragile X syndrome equaled or exceeded that of patients found to be positive for fragile X. Our figures, consistent with those reported in the literature, underscore the value of routine karyotyping in this population of patients.

Child↗
PubMedDate not supplied

Reproducibility of LSI HER-2/neu SpectrumOrange and CEP 17 SpectrumGreen Dual Color deoxyribonucleic acid probe kit. For enumeration of gene amplification in paraffin-embedded specimens: a multicenter clinical validation study.

Overexpression and/or amplification of HER-2/neu gene have been found to be prognostic and predictive in breast and other cancers. Fluorescence in situ hybridization (FISH) assay, with its sensitivity and specificity, can be a superior method of detection when its performance characteristics are demonstrated. A multicenter study was initiated to evaluate the reproducibility of the LSI HER-2/neu SpectrumOrange and CEP 17 SpectrumGreen Dual Color DNA Probe for enumeration of both the HER-2/neu gene and chromosome 17 (signals) in interphase cells. Section slides were prepared from four cell lines (H, E, R, and N) with known ratios of the HER-2/neu to CEP 17 copy numbers (approximately H = 1.10, E = 1.70, R = 4.50, N = 9.0). The study variable was the ratios of the HER-2/neu to chromosome 17 copy numbers. Reproducibility with respect to assay, site, lot, day and reader was evaluated at 3 centers. Out of 120 specimen slides, 100 percent were successfully assayed. There were no significant differences among: (1) four repeated assays of the same specimen (p = 0.99), (2) the four probe lots (p = 0.33), or (3) the four study days (p = 0.54). There was statistically significant, but not important differences among centers and between readers. The ratios of the HER-2/neu to chromosome 17 copy numbers were estimated with accuracy and precision; the mean ratios (and sd) for specimens, H, E, R, and N were 1.05 (0.06), 1.81 (0.12), 4.48 (0.28), and 8.60 (1.23), respectively. In summary, assays with the LSI HER-2/neu and CEP 17 Dual Color DNA Probe Kit, conducted at three sites by 6 different technicians, over 8 assay days, using kits from four lots, were performed with a high success rate in paraffin-embedded specimens. The signal enumeration was also accurate and precise. This study demonstrated that the results obtained by using the LSI HER-2/neu SpectrumOrange and CEP 17 SpectrumGreen Dual Color DNA Probe Kit are reliable and reproducible.

Breast Neoplasms↗