Biomedical subjects

L Gras

Publications and source records attributed to L Gras.

22 records · Page 2Linked to original sources

PubMed1988

Mousepox in inbred mice innately resistant or susceptible to lethal infection with ectromelia virus. IV. Studies with the Moscow strain.

The pathogenesis and transmission of infection with the Moscow strain of ectromelia virus were studied in inbred mice. BALB/cAnNcr had high morbidity and mortality and C57BL/6Ncr (B6) mice had high morbidity and low mortality. Virus was detected in B6 mice for 2 weeks after subcutaneous (s.c.) inoculation and infected mice developed lesions compatible with acute mousepox. B6 inoculated by footpad transmitted infection to cagemates for up to five weeks and soiled cages that had housed infected mice were infectious for three weeks. S.c.-inoculated B6 mice also transmitted by contact for 2 weeks. Transmission was attributed to oronasal excretion of virus. Airborne transmission of infection between adjacent cages occurred at a low rate. Ectromelia virus-free progeny were derived from previously infected dams. These studies indicate that the highly virulent and infectious Moscow strain of ectromelia virus caused self-limiting infection in inbred mice and that direct contact is the most efficient means of transmission. These findings support the concept that mousepox can be contained by husbandry practices that minimize or eliminate the spread of infection by direct contact or fomites.

Animals↗

PubMed1980

Two dicentric Y isochromosomes, one without and the Yqh heterochromatic segment: review of the Y isochromosomes.

Two women with primary amenorrhoea and few other stigmata of Turner's syndrome were found to be chromosome mosaics: 45,X/46,X,idic(Y). In Case 1, the dicentric isochromosome Y was found to have a long-arm breakpoint of formation. This structure was interpreted as containing two Y short arms and centromeres separated by a region derived from the proximal Y long arm. One of the centromeres in the Case 1--idic(Y) was suppressed in 80% of cells in blood, and in these cells it appeared as a regular Y-shaped chromosome. In Case 2 the idic(Y) was derived by a short-arm breakpoint of formation. In all the dicentrics of this case with one primary constriction (functional monocentrics) there was a single Cd band. In the 10% of dicentrics with two primary constrictions, there were two Cd bands. It is argued that the instability of sex isochromosomes is due to this functional dicentricity in some cells. These cases are compared with 42 other Y isochromosomes with various short- and long-arm breakpoints of formation. It is suggested that some of the nonheterochromatic, nonfluorescent Y chromosomes previously reported may be explained as dicentric i(Y) with proximal long-arm breakpoints of formation and one suppressed centromere.

Adolescent↗

PubMed1975

Unusual chromosomal changes in polycythaemia vera.

Of 13 cases of polycythaemia vera in which direct bone marrow culture was carried out for chromosome analysis, a consistent count of 48 chromosomes was found in two on admission to the hospital. Neither patient showed evidence of blastic transformation.

Aged↗

PubMedDate not supplied

Diagnosis of trisomy 21 in preimplantation embryos by single-cell DNA fingerprinting.

Many couples presenting for preimplantation genetic diagnosis (PGD) for a single gene disorder are of advanced reproductive age (>35 years) and have a greater chance of producing embryos with chromosomal aneuploidies. The most common chromosomal aneuploidy observed in newborns is trisomy 21, or Down's syndrome. Consequently, the availability of a highly reliable system that simultaneously detects the heritable gene disorder and trisomy 21 would be beneficial to couples at specific risk. A pentaplex chromosome 21 (Ch 21) single-cell DNA fingerprinting system was developed in a multiplex fluorescence polymerase chain reaction (FL-PCR) on single cells. High reliability and accuracy rates were observed, together with low allele dropout (ADO) and preferential amplification rates on diploid buccal cells, trisomy 21 buccal cells and blastomeres derived from Ch 21 aneuploid embryos. A combined multiplex FL-PCR format was optimized with the common cystic fibrosis delta F508 mutation and validated on single buccal cells from a carrier of the cystic fibrosis delta F508 mutation. This new test is a very powerful technique, which also allows confirmation of the embryo parentage and the identification of extraneous DNA contamination that could cause a misdiagnosis in PGD cases.

Blastocyst↗