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Biomedical subjects

E E Evans

Publications and source records attributed to E E Evans.

At least 19 recordsLinked to original sources
PubMed1991

The effects of betamethasone on maternal cellular resistance to infection.

Antenatal administration of glucocorticoids is often used to facilitate fetal lung maturation in cases of prematurity; however, the effects of betamethasone on maternal immune function have not been established. Therefore maternal immune function was assessed with the use of in vitro techniques. Transient and incomplete suppression of the proliferative response to the T-cell mitogen phytohemagglutinin was demonstrated as early as 24 hours after administration of betamethasone. The magnitude and duration of suppression showed a corresponding increase with advancing gestational age, but these effects were not cumulative and were always short-lived (less than 72 hours). No such suppression of the B-cell mitogen lipopolysaccharide was detected. The nonspecific cellular resistance to infection of maternal monocytes was determined through coincubation with the facultative intracellular pathogen Listeria monocytogenes. Increased phagocytic activity with a normal bactericidal effect was measured in the cell preparations obtained from recipients versus nonrecipients of betamethasone. Taken together, these findings clearly show that both specific and nonspecific immune function are intact in the preterm gravid woman after administration of betamethasone and should allay concerns over its use for reasons of infection control alone.

Betamethasone↗
PubMed1988

Hereditary pituitary prolactinomas: a new rat model.

Pituitary adenomas are known to occur spontaneously in several rat strains, especially during aging. Here we report the occurrence of adenomas (prolactinomas) in a new rat model at an early age. The adenomas were characterized by light and electron microscopy and histochemically by immunoperoxidase methods using specific antisera. Of the 53 pituitaries examined, one was normal, two were hyperplastic and the remainder were adenomas. Among the latter, there were 37 prolactinomas (70%), 3 GH-producing tumours and 2 ACTH-containing neoplasms. One microadenoma produced both PRL and GH. The remaining 8 adenomas were histochemically negative for all pituitary hormones. Serum PRL levels were elevated in both sexes while serum testosterone was high in females and low in the males. The serum estrogen levels were elevated in the males with prolactinomas. The prolactinomas appear to be transmitted as an autosomal dominant characteristic with incomplete penetrance and a greater incidence in the male.

Animals↗
PubMed1973

Comparative immunology: sipunculid bactericidal responses.

This report continues comparative studies of inducible bactericidins of invertebrates. The bactericidin of the sipunculid worm Dendrostomum zostericolum Chamberlain was induced by intracoelomic injections of killed bacteria. With the assay system used, optimal results were obtained with 90 min of incubation at 20 to 35 C. Bactericidal titers in coelomic fluids from noninjected worms were either low or nonexistent. After injections of gram-negative bacteria, bactericidal titers of up to 1:1280 were reached within 7 days. Considerable individual variations were noted. Optimal stimulation was achieved with 4 x 10(8) bacteria per injection. The response was relatively nonspecific as measured by cross-immunization and absorption experiments. Injections of sterile sea water produced no response. Coelomic fluids could be inactivated by heating at 50 or 56 C for 20 min. Activity was not restored by a pool of unheated coelomic fluid from nonimmunized worms. The significance of these observations was discussed with reference to immunity of sipunculids and to comparative immunology.

Bacteria↗
PubMed1971

Bactericidal antibody response in the Pacific hagfish, Eptatretus stoutii.

The hagfish, Eptatretus stoutii, has been shown to synthesize bactericidal antibodies after injections of gram-negative organisms. These bactericidins could be detected as early as 2 days after the primary injection. Secondary responses were accelerated, although titers were not significantly higher than those reached in the primary response. The bactericidins of hagfish were found to react with other gramnegative enteric bacteria, but not with gram-positive strains. The bactericidins show a lesser degree of specificity and a shorter induction period than other hagfish antibodies or most antibodies induced in higher vertebrates. The bactericidal activity was temperature dependent and could be irreversibly destroyed by heating at 50 C for 20 min. Immune sera were subjected to gel filtration on Sephadex G-200, and bactericidal activity was found to be associated with the excluded peak indicating a high-molecular-weight component. Evidence indicates that inducible immune responses of this bactericidal type represent a primitive capacity which arose before the emergence of vertebrate species.

Animals↗