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Biomedical subjects

A Richardson

Publications and source records attributed to A Richardson.

At least 343 records · Page 19Linked to original sources
PubMed1979

A comparison of protein synthesis by liver parenchymal cells isolated from Fischer F344 rats of various ages.

Rates of protein synthesis by intact liver parenchymal cells isolated from male Fischer F344 rats ranging in age from 2.5 to 30 months were determined by measuring the incorporation of [3H] valine into acid-insoluble material and the specific activity of the extracellular valine. The rate of protein synthesis decreased 44% from 2.5 to 18 months and then increased slightly (18%) from 18 to 30 months. There was no dramatic change in the types of proteins synthesized by isolated liver parenchymal cells isolated from 2- or 18-month-old rats as determined by SDS-polyacrylamide gel electrophoresis. The ribosomal-transit time by liver parenchymal cells isolated from 18-month-old rats was 60% higher than the ribosomal-transit time of liver parenchymal cells isolated from 4-month-old rats. The fidelity of protein synthesis by parenchymal cells isolated from 4- and 18-month old rats was compared by measuring the incorporation of p-fluorophenyl alanine (an analogue of phenylalanine) into acid-insoluble material. Although protein synthesis decreased significantly from 4 to 18 months, the fidelity of protein synthesis remained constant.

Aging↗
PubMed1979

Organization and interaction in psychiatric day centres.

One of the major problems in the care of chronic patients is the design of suitable long-term environments. Following from the work of Tizard and his colleagues, a study is described which investigated the aspects of the organization, management practices and social interactions in 4 local authority day centres for the care of chronic patients in the community. It was found that these centres differed markedly in terms of their organization and management practices and that these differences were correlated with the nature and quality of staff-client (although not staff-staff) interactions. Client-oriented management attitudes were correlated with a more personal approach to clients' problems and a warmer quality of interaction. These differences did not seem attributable to different kinds of clients being involved in each centre. The results are discussed in terms of the possible causal mechanisms involved and their implications for designing systems of long-term care.

Adult↗
PubMed1979

Evaluation of glenoid labrum by double-contrast shoulder arthrography.

Double-contrast shoulder arthrography was used to define the normal and abnormal arthrographic anatomy of the glenoid labrum. A retrospective study of 12 patients suspected of having labral abnormalities or who had unexplained shoulder disability consistent with capsular laxity was undertaken. In four of the nine patients with abnormal arthrograms, the study revealed critical anatomic alterations not detectable on physical examination or pain radiographs.

Adult↗
PubMed1978

Rates of protein synthesis by hepatocytes isolated from rats of various ages.

The rate of total protein synthesis in isolated hepatocytes was determined. The incorporation of L-[3H]valine into protein is linear for at least two hours of incubation and is affected by the concentration of amino acids in the medium. Uptake of valine by hepatocytes from 1.5- and 18-month-old rats was identical and appears to occur by simple passive diffusion. Within five minutes, the specific activities of the intracellular and extracellular valine pools are equivalent. The specific activities of these pools are saturated by 1.6mM valine and remain constant for 60 minutes of incubation. The rates of protein synthesis by hepatocytes from 1- to 2-month-old rats is 96.8 pmoles of valine per minute per milligram protein. This is comparable to rates of protein synthesis reported for perfused liver and liver in vivo and is approximately 64% higher than the rate of protein synthesis by hepatocytes from 18-month-old rats.

Aging↗
PubMed1978

Comparison of cell-free protein synthesis by different regions of chicken brain.

The cell-free protein synthesis by the postmitochondrial supernatant from chicken cerebrum was twofold greater than protein synthesis by the cerebellum or optic lobes. Ribosomal aggregation of mRNA and ribonuclease activity of the postmitochondrial supernatant from the three brain regions was not statistically different. The higher protein synthetic activity of the cerebral postmitochondrial supernatant was associated with both the postribosomal supernatant (cell sap) and microsomal fractions. Cerebral monomeric ribosomes were more active in polyuridylic acid directed polyphenylalanine synthesis than monomeric ribosomes from either the cerebellum or optic lobes. The ability of cerebral cell sap to support polyuridylic acid directed polyphenylalanine synthesis was 1.6 to 2 times greater than cell sap from the other two regions. Cell sap factors other than tRNAphe or phenylalanyl-tRNA synthetases appear to be responsible for the higher protein synthetic activity of the cbr cell sap.

Amino Acyl-tRNA Synthetases↗
PubMed1978

Comparison of RNA synthesis by liver nuclei from rats of various ages.

RNA synthesis was studied in nuclei isolated from male Fischer F344 rats of various ages. Both the initial rate and the extent of RNA synthesis were determined in two distinct media that result in the preferential synthesis of either mRNA or rRNA by hepatocytes. Synthesis of mRNA and rRNA, as determined by [3H]-UMP incorporation into acid-insoluble material, was shown to increase 1.6- to 3-fold from 3- to 6-months. The increase in RNA synthesis during maturation was followed by a 1.6 to 2.7-fold decrease from 6- to 31-months of age depending upon the assay medium and time of incubation. The age-related changes in RNA synthesis by rat liver nuclei were shown not to be due to changes in RNase activity, UTP uptake, or UTP degradation. RNA synthesized by liver nuclei from rats of various ages was characterized by SDS--polyacrylamide gel electrophoresis. Slight age-related differences in the size distribution of RNA isolated from liver nuclei were observed when nuclei from rats of various ages were incubated with [3H]-UTP in either assay medium.

Aging↗
PubMed1978

Inhibition of cell-free protein synthesis by analogues of aurintricarboxylic acid.

Aurintricarboxylic acid is a potent inhibitor of cell-free protein synthesis by the post-mitochondrial supernatant of chick brain and the translation of mRNA by wheat germ lysate. Comparison of commercially available and chemically synthesized analogues of aurintricarboxylic acid indicates that the unique aurin triphenyl methane ring system and the carboxylic acid groups are both necessary for inhibition of cell-free protein synthesis in both systems.

Animals↗