Biomedical subjects

G Richards

Publications and source records attributed to G Richards.

At least 145 records · Page 8Linked to original sources

PubMed1982

Randomized trial of aminoglutethimide versus tamoxifen in metastatic breast cancer.

We compared antiestrogen therapy (tamoxifen) with an estrogen suppression regimen (aminoglutethimide-hydrocortisone) in postmenopausal women with metastatic breast carcinoma. Fifteen of 39 patients (38%) who received tamoxifen experienced an objective tumor regression (3 complete, 12 partial remissions), whereas 13 of 36 women (36%) receiving aminoglutethimide responded (one complete remission, 12 partial remissions). The median duration of response was similar. The site of tumor involvement appears to be important in choosing between these hormonal treatments. Aminoglutethimide appears to offer a greater chance of response in patients with bone involvement.

Aminoglutethimide↗

PubMed1982

Bioactive antibiotic levels in the human aorta.

A new bioassay was used to determine the level of active antibiotic within the aortic wall in 24 patients undergoing elective aortic surgery involving prosthetic grafts. The patients were divided into three groups and received either cefazolin, clindamycin, or cefoxitin intravenously at the induction of general anesthesia. Cefazolin and cefoxitin attained satisfactory tissue levels. Clindamycin did not reach therapeutic levels in the aortic wall. Blood levels did not correlate well with tissue levels.

Adipose Tissue↗

PubMed1981

Cytogenetic analysis of the 2B3-4-2B11 region of the X chromosome of Drosophila melanogaster. II. Changes in 20-OH ecdysone puffing caused by genetic defects of puff 2B5.

Larvae homozygous or hemizygous for the l(1)t435 mutation located within the early ecdysteroid puff 2B5, or carrying a deletion of the 2B5 band, die at the end of the third larval instar. In the salivary gland chromosomes of these larvae only intermoult puffs are detected. If these salivary glands are incubated in vitro with 20-OH ecdysone for 6 h the intermoult puff 68 C remains large, some early puffs (74EF and 75B) are induced to 30-40% of their normal size, other early (63F) and all late puffs (62E, 78D, 82F and 63E) are not induced at all. Puff 2B5 reaches its normal size but does not regress after 6 h incubation with 20-OH ecdysone, as it does in normal stocks. The data obtained in this study show the existence of a locus (or loci) in the band (puff) 2B5 which is necessary for the normal response of the salivary gland chromosomes to the hormone 20-OH ecdysone.

Animals↗

PubMed1981

The radioimmune assay of ecdysteroid titres in Drosophila melanogaster.

The use of radioimmune assays to determine ecdysteroid titres during insect development has become widespread in recent years. In this review I consider the application of these assays to studies on the development of Drosophila melanogaster. In all, 8 studies have been undertaken with somewhat conflicting results. I discuss the underlying problems in these studies and relate them to studies in Calliphora and Manduca. I also consider evidence from in vitro studies of Drosophila tissues regarding the levels of circulating, biologically active, ecdysteroids and argue that the fluctuations so far described are not sufficient to explain the control functions ascribed to ecdysteroids in many developmental processes.

Animals↗

PubMed1981