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Biomedical subjects

L J Ross

Publications and source records attributed to L J Ross.

At least 55 records · Page 3Linked to original sources
PubMed1976

2-Deoxy-D-glucose uptake by chick embryo cells: a biochemical indicator of genetic susceptibility to RNA tumour viruses.

The enhanced glucose uptake by chick embryo cells as early as 72 h after infection with Rous sarcoma virus (RSV) was confirmed in this study to be an early indicator of cellular transformation. The glucose uptake of C/E BrL cells infected by various doses of BS-RSV of subgroup A showed that the relationship between the log-dose of virus and log-uptake was linear (slope, b1 = 1.30 +/- 0.14) when the ratio of the number of infectious virus particles to the number of cells in the culture was above 1:200. But infection of cultures with a relatively high dose of virus, for instance 10(3.5) focus forming units (f.f.u.) was ineffective for the measurement of cellular transformation using the criterion of glucose uptake, whereas a much lower dose such as 10(1.7) f.f.u. was sufficient to induce foci of transformed cells. We concluded therefore that the statistic of glucose uptake assay (GUA) measured at 72 p.i. is less sensitive than that of the focus count assay (FCA) measured after 10 days as a measure of assessing cellular transformation by RSV. Nevertheless, when the cultures were infected with a higher dose of virus (10(4.3) f.f.u. or more), the GUA could discriminate between the transformed (T) and non-transformed (NT) cultures. This was demonstrated in the two genetic crosses, line 7-2 X WC(F1) and line 7-2 C line. Embryo cultures of these two test-crosses were infected with viruses of subgroups A, B, C and D, and the T and NT phenotypes were ascertained. Also, on the basis of focus counts in the cultures the genetically resistant (R) and susceptible (S) phenotypes in response to various infections were determined. The T and NT phenotypes based on the GUA were compared with the S and R phenotypes, respectively, based on the FCA. It was found that in 47 of the 51 cultures, the phenotypic agreement was perfect, suggesting that glucose uptake by cells of embryo cultures exposed to RSV is a biochemical indicator of genetic susceptibility. The discordant results in 4 cultures are discussed in the light of present knowledge of cellular transformation by RSV.

Animals↗
PubMed1975

Immunization against Marek's disease using Marek's disease virus-specific antigens free from infectious virus.

Immunity against Marek's disease was conferred by the use of non-infectious materials extracted with non-ionic detergents from cells infected with the attenuated strain of Marek's disease virus (MDV). Antibody-free Rhode Island Red chicks were inoculated at 1 week of age with cell extracts emulsified in Freund's complete adjuvant and were given a second inoculation 1 week later without adjuvant. Protection against natural infection was obtained in groups inoculated with both soluble (not sedimented at 100,000 times g/2h) and insoluble antigens present in Nonidet P40 (NP40) extract, but only with the insoluble fraction of deoxycholate extract. The results suggest that the immunizing antigens can be partially solubilized with 0.5% NP40 and that the growth and spread of MDV are reduced in immunized chickens.

Animals↗
PubMed1975

Serological relationship between a pathogenic strain of Marek's disease virus, its attenuated derivative and herpes virus of turkeys.

Precipitating antigens present in extracts of chick embryo cells infected with the HPRS-16 attenuated strain of Marek's disease virus (att-MDV) were separated by gel filtration on Sephadex G200 and some of their properties determined. The two main antigens detected with convalescent MD serum, referred to as 'B' and 'C' antigens, had mobilities of 0-55 and 0-25 respectively relative to phenol red on electrophoresis in 7-5% acrylamide gel. The B antigen was relatively stable and of low mol. wt. in comparison with the C antigen. B and C antigens were in some instances also detected in culture medium of infected cells, but were distinguishable from the A antigen, a major glycoprotein antigen released into the culture medium of cells infected with HPRS-16. The results of immunodiffusion studies suggest that B antigen is common to MDV and strains of herpes virus of turkeys(HVT) and that at least 2 antigens (including C) are MDV specific. The A antigen was also common to MDV and HVT strains. It was noted however that the capacity of HPRS-16/att to synthesize A antigen was considerably reduced in comparison with HPRS-16 and HVT strains, and in some preparations the A antigen could not be detected. Evidence was also obtained for the presence of HVT-specific antigens associated mainly with the cell fraction.

Animals↗
PubMedDate not supplied

Developmental disabilities: genetic implications.

Knowledge and new techniques in genetics can aid in a better understanding of developmental disabilities. Through new treatments and better assessment skills, individuals with disorders such as phenylketonuria (PKU), Down syndrome, and fragile X syndrome are having diagnoses sooner and are living into adulthood. With the passage of public law 99.457, early intervention services are mandated for those who are 3 years old or younger and are developmentally delayed or at risk for delay. Organizations for paraprofessionals and professionals in the arena of developmental disabilities and genetics exist to create a forum for future action, awareness, and direction.

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