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Biomedical subjects

D Blakey

Publications and source records attributed to D Blakey.

29 records · Page 2Linked to original sources
PubMed1995

Three-probe fluorescence in situ hybridization to assess chromosome X, Y, and 8 aneuploidy in sperm of 14 men from two healthy groups: evidence for a paternal age effect on sperm aneuploidy.

The method of simultaneous three-chromosome fluorescence in situ hybridization (FISH) was developed using repetitive DNA sequence probes for chromosomes 8, X and Y and applied to semen of 14 men from two healthy groups who differed in their average ages (46.8 +/- 3.1 years, n = 4 v. 28.9 +/- 5.0 years, n = 10). The frequencies of disomic sperm determined by FISH compared well with frequencies obtained using the hamster-egg technique for human-sperm cytogenetics and with the frequencies of disomic and diploid sperm reported in previous FISH studies in this laboratory. The two groups of men did not differ in their baseline frequencies of sperm disomic for chromosome 8 (approximately 6.5 per 10(4) sperm), sperm with XY8 aneuploidy (approximately 9.5 per 10(4) sperm), or sperm with autodiploidy XX88 or YY88 (approximately 2 per 10(4) sperm). However, the older group had statistically higher frequencies of sperm carrying sex chromosomal disomy than the younger group (5.1 v. 2.2 per 10(4) sperm for XX8; 5.9 v. 2.0 per 10(4) sperm for YY8; P < 0.005). A recent report from this laboratory of sex-chromosomal aneuploidy in sperm of aged mice provides inter-species corroborating evidence for this preliminary finding of a paternal age effect on sperm aneuploidy in human males.

Adult↗
PubMed1995

A proposed system for scoring structural aberrations detected by chromosome painting.

The advent of chromosome painting has brought the realization that structural aberrations can be far more complicated than previously imagined. Various investigators have devised their own nomenclature systems to deal with this difficulty, with the result that the terminology has become inconsistent and confusing. Recently, an international group of cytogeneticists experienced in chromosome painting gathered to address this issue. Results of the meeting are presented in this report, which provides a nomenclature system capable of describing chromosome aberrations that occur between painted and unpainted chromosomes, as well as aberrations involving only painted chromosomes. The nomenclature is flexible enough to describe accurately even the extensively rearranged chromosomes. As a consequence of this flexibility, the scheme upon which the nomenclature is based differs substantially from other systems of aberration classification. We call this system the Protocol for Aberration Identification and Nomenclature Terminology (PAINT).

Chromosome Aberrations↗
PubMed1994

Suppression of tumorigenicity in human teratocarcinoma cell line PA-1 by introduction of chromosome 4.

Teratocarcinomas are tumors that develop spontaneously in the gonads and usually contain a rapidly dividing, undifferentiated stem cell population. Immature ovarian teratocarcinomas are highly malignant with only 30-60% of patients surviving for 2 years after diagnosis. We have used microcell fusion to introduce individually tagged normal human chromosomes into the PA-1 human teratocarcinoma cell line. Introduction of human chromosome 4 caused a cell morphology in culture and suppressed PA-1 tumorigenicity in nude mice, whereas addition of portions of either chromosome 7 or 12 had no effect on the cell phenotype. The PA-1 cell line regained its tumorigenicity when the tagged chromosome 4 was lost under negative selection. We conclude that there is a putative tumor suppressor gene on human chromosome 4 whose expression interferes with the tumorigenicity of PA-1 cells.

Animals↗
PubMed1981

Transmission of multiple drug-resistant tuberculosis: report of a school and community outbreak.

An outbreak of tuberculosis in 1976 was caused by mycobacteria resistant to isoniazid (INH), streptomycin (SM), and para-aminosalicylic acid (PAS). High rates of infection associated with exposure to the index case suggested that transmission of resistant organisms had occurred, and the subsequent appearance of bacteriologically proven INH-SM-PAS-resistant tuberculosis in four school contacts of the index case confirmed this fact. Retrospective investigation revealed that the school outbreak was part of an ongoing community outbreak dating back at least to 1964. Through the use of case histories, drug-susceptibility patterns, and phage typing, 15 documented and seven presumed INH-SM-PAS-resistant, epidemiologically linked cases were found; two of these persons died of tuberculosis. Six additional cases with INH-SM-PAS resistance that could not be epidemiologically linked to the outbreak were also identified. The potential of drug-resistant strains for causing disease in humans should not underestimated.

Adolescent↗
PubMedDate not supplied

Site-specific conjugation of an enzyme and an antibody fragment.

A site-specific immunoconjugate was prepared between an F(ab')2-like fragment of the monoclonal anti-CEA murine IgG1 A5B7 and a mutant of the dimeric enzyme carboxypeptidase G2 possessing an N-terminal Thr in place of Ala. First an aldehyde was introduced at the N-terminus of the enzyme by mild periodate oxidation and a residue of carbohydrazide was specifically introduced at the C-terminus of the truncated heavy chain of the F(ab')2-like fragment by reverse proteolysis. Then the two modified proteins were conjugated by the formation of a hydrazone bond between the hydrazide and the aldehyde groups. The conjugate obtained retained both enzymic activity and antigen-binding capacity. The antigen-binding capacity was better than that of a similar conjugate made conventionally by random reaction with side chains.

Antibodies, Monoclonal↗