Biomedical subjects

M H Russell

Publications and source records attributed to M H Russell.

5 recordsLinked to original sources

PubMed1991

The visual defect in multiple sclerosis and optic neuritis. A combined psychophysical and electrophysiological investigation.

Chromatic and achromatic visual function were investigated using psychophysical and evoked potential techniques in 32 patients with multiple sclerosis (MS) or optic neuritis. There was no evidence for either chromatic or achromatic vision being selectively damaged. There was, however, some evidence that demyelination of the optic nerve causes a visual defect in which the transmission of high temporal frequencies is imparied. In some patients either a red or blue deficit was evident, but overall there was no evidence of a wavelength specific colour vision defect in our patient group. Reduction of chromatic sensitivity as determined psychophysically had a statistically significant correlation with the amplitude and latency of the chromatic visual evoked potential.

Adult↗

PubMed1991

Small bowel function after aortic surgery.

One cause of post-operative morbidity in the elective repair of abdominal aortic aneurysms is the development of a paralytic or 'adynamic' ileus. In a series of 20 consecutive patients undergoing such a procedure, the maintenance of small bowel motility and absorptive capacity in the immediate post-operative period was assessed using barium sulphate and xylose passed down a naso-duodenal tube sited at the time of surgery. This simple study demonstrated that small bowel function was preserved in all cases, and hence that patients could be fed enterally via naso-duodenal tube (in particular using very low residue formulae) rather than using costly parenteral regimens, should an ileus persist.

Aorta, Abdominal↗

PubMed1979

Extent and rate of chromosome segregation in two intraspecific mouse cell hybrids: A9 x diploid foetal erythrocyte and A9 x B82.

Patterns of chromosome segregation were studied in 2 different intraspecific mouse cell hybrids: (1) A9 x B82, formed by fusing 2 cell lines of heteroploid fibroblasts, and (2) UWE, originating from the fusion of A9 cells with euploid foetal erythrocytes. Detailed analyses of Giemsa (G)-banded chromosomes and chromosome arms of both parental and hybrid cells were made for each hybrid type, in order to determine the specificity of the losses and to assess the influence of ploidy and cell differentiation. Unlike the A9 x B82 hybrids, which revealed a significant chromosome loss under selective tissue culture pressures only after 9 months, the UWE hybrids showed a sharp reduction in the total chromosome number during the initial 2 months under similar pressures. However, with no additional cloning, UWE remained karyotypically stable after that time. This rapid chromosomal segregation in UWE hybrids may be caused by properties of the parental foetal erythrocytes. In UWE cells, the majority of the chromosome arms were retained or duplicated. Less than a quarter of the total number of chromosome arms were segregated or lost, and these were all chromosome arms with abnormal mouse G-banding patterns, present only in the heteroploid A9 parental cells. In two of the four A9 x B82 hybrid lines, there was marked segregation of chromosome arms whose banding patterns were identical to those of wild type mouse telocentric chromosomes. For both types of intraspecific cell hybrids, two thirds or more of the chromosome arms had banding patterns which were the same as those of the wild type genome.

Animals↗

PubMed1977

Karyotypic analyses of parental and hybrid intraspecific mouse cells, A9/B82, by giemsa- and centromeric-banding.

Hybrids between A9 (HGPRT-) and B82 (TK-), mouse heteroploid fibroblast lines, were obtained through continuous cultivation and clonal selection; such hybrids showed marked segregation and by conventional stains displayed chromosome numbers and distribution similar to that of either parental type. Detailed analyses by Giemsa (G)- and centromeric-banding of these parental lines, and of 4 of the reduced hybrids, maintained in culture for up to 5 years, revealed the following points: (1) The distribution of the majority of individual chromosomal classes was similar for 3 of the hybrid cell lines. (2) Over two-thirds of the chromosomal arms in both the parental lines and hybrid lines were identical to normal mouse telocentric chromosomes. (3) For 2 of the hybrid lines, segregation was particularly marked with respect to those chromosomal arms whose G-banding patterns were identical to the wild-type genome; this indicated that segregation had occurred at the expense of redundant chromosomal material introduced by cell fusion. These banded studies demonstrated that segregation chiefly accounted for the sharp reduction in chromosome numbers while recombination accounted for the chromosome heterogeneity of the hybrid cells as compared to the parental genomes.

Animals↗

PubMed1976

Transformation of mouse cells by fusion with chronic granulocytic leukemia cells: possible role of human chromosome.

In vitro properties of somatic cell hybrids between non-malignant B82 mouse fibroblasts and human chronic granulocytic leukemia spleen cells include lack of cell density-dependent growth inhibition and growth in soft agar. These phenotypic expressions of cell transformation appear linked to the retention by the cells of chromosome 7 from the human leukemic genome.

Animals↗