Biomedical subjects

R L Baker

Publications and source records attributed to R L Baker.

At least 73 records · Page 4Linked to original sources

PubMed1976

Antithymocyte antiserum therapy in myasthenia gravis.

The therapeutic effect of goat anti-human thymocyte antiserum globulin (ATG) was assessed in 10 patients with myasthenia gravis. Prolonged, low dose therapy was used with 1-0--1-6 grams protein administered intramuscularly over a 28-73 day period. Varying degrees of therapeutic response were noted in 8 patients. Fllow-up examinations for over 5 years have been maintained and relapse rates determined. The clinical criteria for aptients selection and characteristics of therapeutic response are presented.

Adolescent↗

PubMed1975

Direct response to selection for postweaning gain in the rat.

The effectiveness of selection for 3-9 week gain was examined in a population of rats with a history of past selection for high 3-9 week gain. Lines were selected for high (U line) and low (D line) 3-9 week gain with two replicates of each line. Two randomly selected lines were also kept, one originating from the same base population as the two selected lines (R line) and the other originating from a population that had been randomly mated for the previous 27 generations (C line). Two replicates of each of these lines were kept. After seven generations of selection, a randomly selected line (relaxed line) was formed from each of the two upward- and each of the two downward- selected lines. Results have been presented for 13 generations of selection. The environmental trend for 3-9-week gain, as indicated by the randomly selected R and C lines, was consistently negative in all four lines. Realized heritabilities calculated by deviating the response to selection from the trend in the R or C lines resulted in non-significantly higher values in the D lines than the U lines. Six generations of relaxation of selection indicated no effect of natural selection in the U lines or the D lines. The relative magnitude of the drift, error and common environmental variances were estimated by the methods given by HILL (1971). The estimates of these parameters then led to calculation of the degree of bias in the sampling variances of the realized heritability estimates. As was predicted by HILL (1971), estimates of the variance of realized heritabilities obtained by using standard regression techniques were less than those obtained using HILL'S formulae. The results are discussed in relation to other similar studies with rats and mice.

Analysis of Variance↗

PubMed1975

Correlated responses to selection for postweaning gain in the rat.

Evidence for correlated responses to selection was investigated in lines of rats selected for 13 generations for high (U line) and low (D line) 3-9-week gain in comparison with random-bred control lines (R and C lines). The increase in 3-9-week gain in the U lines was shown to be due largely to an increase in 9-week weight, although 3-week weight also increased in these lines. In the D lines, where a marked decrease in 3-9-week gain was observed, this was found to be due to a large decrease in 9-week weight and no detectable change in 3-week weight. The average 2-week litter weight, a measure of the lactational performance of the dam, was significanly greater in the U lines than in the D lines. Selection for 3-9-week gain in these lines of rats led to changes of litter size at birth in the same direction as that of selection. This resulted in a significantly higher litter size in the U lines than in the D lines. The number of rats alive 2 and 9 weeks of age and the percentage of mated females pupping were similar in the U and D lines but lower in these lines than the random bred C lines, providing evidence for a reduction of "fitness" in the selected lines. Carcass composition was studied for all lines at the 11th generation of selection. Carcass composition, in terms of water, fat, ash and protein, was similar in the R and C lines. The U lines had more water and lesss fat than the R or C line. The D lines had similar carcass composition to the R and C lines. It is suggested that these selected and random-bred lines of rats are potentially useful animals to investigate further the developmental and physiological mechanisms which control growth.

Adipose Tissue↗

PubMed1974