Biomedical subjects

M S Singer

Publications and source records attributed to M S Singer.

57 records · Page 4Linked to original sources

PubMed1981

Specific rosette formation between fibroblasts and erythrocytes.

Fibroblast cells (BHK-21, Swiss 3T3, SV403T3, L929) will form rosettes by binding to erythrocytes of specific types. The specificity of binding varies with the cell line. Monolayer cultures of spread baby hamster kidney (BHK) cells also bind erythrocytes with the same specificity exhibited by suspended cells. Our studies have concentrated on rosette formation between trypsinzed-ox (TOx) erythrocytes and BHK cells. Extensive protease treatment of the BHK cells reduces their ability to bind TOx erythrocytes in a dose- and time-dependent manner, suggesting the involvement of protein in the binding site. Simple saccharides, and glycopeptide isolated from ox erythrocyte ghosts, do not inhibit rosetting. However, neutral glycosphinogolipids from ox erythrocyte ghosts inhibit BHK-TOx rosetting, whereas neutral glycosphingolipids from non-rosetting rabbit erythrocytes have no effect on rosetting. Furthermore, incorporation of ox glycolipids into guinea-pig erythrocytes causes these non-rosetting erythrocytes to adhere to BHK cells. These experiments suggest that specific glycolipids of the ox erythrocyte act as receptors for binding sites on the cell surface of BHK cells. These cell-specific binding sites may play a role in cell-surface events involving carbohydrate recognition.

Animals↗

PubMed1978

Incompetent cervix in a hormone-exposed offspring.

Intensive interest has focused on DES-exposed men and women since the first reports on this in the early 1970s. We are presenting here what we feel is the first case of incompetent cervix in a DES-exposed female. It is hoped that this will stimulate further interest in the functional as well as anatomic problems which these individuals experience.

Adolescent↗

PubMedDate not supplied

Contrasting responses to desiccation and starvation by eggs and neonates of two lepidoptera.

We examined the effects of desiccation on eggs and first-instar larvae of two species of Lepidoptera, Grammia geneura (Arctiidae) and Manduca sexta (Sphingidae). Grammia geneura occurs primarily in grasslands and savannas of the southwestern United States; M. sexta co-occurs with G. geneura but also is cosmopolitan across much of the Western Hemisphere. Eggs of G. geneura exposed to 0% relative humidity (RH) lost water much less rapidly (7.6 microg d(-1); 2.4% d(-1)) than did eggs of M. sexta (79.5 microg d(-1); 5.7% d(-1)). Eggs of both species survived at rates exceeding 75% at both 0% and 85% RH. Neonates of the two species responded differently to desiccation and starvation. In 85% RH, larval G. geneura survived at high rates (>80%) without access to food or water up to day 17, and in 0% RH, they survived at rates exceeding 50% through the first 10 d. Larvae at 0% RH lost mass very slowly (7.2 microg d(-1); 2.9% d(-1)), which was attributable both to low rates of water loss and to an ability to reduce metabolic rate to low levels. Larval M. sexta, in contrast, had rates of mortality that were much higher: after 1 d, fewer than 30% were alive in either group, and by about 1.5 d, all were dead. Neonate M. sexta also lost mass much more rapidly at 0% RH, about 329 microg d(-1). Water from metabolism appeared to contribute significantly to the water budget of G. geneura but not of M. sexta. These data show that G. geneura and M. sexta can inhabit similar macroclimates via remarkably different physiologies.

Animals↗