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Biomedical subjects

A del Rey

Publications and source records attributed to A del Rey.

49 records · Page 3Linked to original sources
PubMed1986

Immunoregulatory feedback between interleukin-1 and glucocorticoid hormones.

The production and action of immunoregulatory cytokines, including interleukin-1 (IL-1), are inhibited by glucocorticoid hormones in vivo and in vitro. Conversely, glucocorticoid blood levels were increased by factors released by human leukocytes exposed to Newcastle disease virus preparations. This activity was neutralized by an antibody to IL-1. Therefore the capacity of IL-1 to stimulate the pituitary-adrenal axis was tested. Administration of subpyrogenic doses of homogeneous human monocyte-derived IL-1 or the pI 7 form of human recombinant IL-1 to mice and rats increased blood levels of adrenocorticotropic hormone (ACTH) and glucocorticoids. Another monokine, tumor necrosis factor, and the lymphokines IL-2 and gamma-interferon had no such effects when administered in doses equivalent to or higher than those of IL-1. The stimulatory effect of IL-1 on the pituitary-adrenal axis seemed not to be mediated by the secondary release of products from mature T lymphocytes since IL-1 was endocrinologically active when injected into athymic nude mice. These results strongly support the existence of an immunoregulatory feedback circuit in which IL-1 acts as an afferent and glucocorticoid as an efferent hormonal signal.

Adrenocorticotropic Hormone↗
PubMed1985

Changes in plasma hormone profiles after tumor transplantation into syngeneic and allogeneic rats.

Transplantation of 2 chemically (DMBA, MCA)-induced tumors into syngeneic female or male DA strain rats elicited hormonal changes during tumor growth. Plasma levels of 7 different hormones were studied. Tumor cells in syngeneic recipients produced a biphasic decrease in insulin, an early increase in prolactin, and a late-phase decrease in thyroxine. Corticosterone decreased in female tumor bearers but increased in males. This difference may reflect differences in the tumors transplanted. Male rats had a decrease in testosterone during the late phase of tumor growth, while females had a biphasic decrease in progesterone and a late-phase increase in growth hormone. The tumors used were moderately immunogenic in syngeneic recipients. However, tumor transplantation to allogeneic recipients produced an early decrease in growth hormone and no change in insulin, corticosterone or thyroxine. Further, transplantation of normal liver cells to syngeneic or allogeneic recipients produced no hormonal abnormalities. This study demonstrates that hormonal changes which are not observed with normal cells or allogeneic tumor transplantation can occur within 2 days of syngeneic tumor transplantation. Progressive tumor growth is characterized by a worsening endocrine imbalance which involves multiple hormone systems.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Endogenous blood levels of corticosterone control the immunologic cell mass and B cell activity in mice.

An inverse relation between endogenous levels of glucocorticoids and splenic mass and cellularity was detected. Decreased endogenous corticosterone blood levels result in an increased number of immunoglobulin-secreting cells in the spleen, a fact that cannot be attributed only to the expansion of the lymphoid cell mass. The opposite phenomenon was observed in animals with high corticosterone blood levels, which showed reduced numbers of immunoglobulin-secreting cells. It is concluded that endogenous glucocorticoid levels contribute to the control of B cell activity and possibly to the interaction of these cells with other immunologic cells.

Adrenalectomy↗
PubMed1983

The immune response evokes changes in brain noradrenergic neurons.

A decreased noradrenaline turnover in the hypothalami of rats was observed at the peak of the immune response to sheep red blood cells. The decrease in noradrenergic neuronal activity was mimicked by injection of soluble r mediators released by immunological cells activated in vitro. Noradrenaline also tended to decrease in the brainstem but not in the residual brain. It is suggested that products released from activated immunological cells during the immune response may induce the previously described autonomic and endocrine mechanisms that contribute to immunoregulation.

Animals↗
PubMed1982

Sympathetic immunoregulation: difference between high- and low-responder animals.

A quantitative relationship is reported between the magnitude of the immune response of rats to sheep red blood cells and diminution of splenic norepinephrine (NE). A decrease in concentration and content of NE in the spleen on day 3 after immunization was evident in both high- and low-responder animals, whereas a diminished concentration of NE persisted only in the high responders. This continuing NE diminution in high-responder animals is associated with increase in spleen weight, probably attributable to blood accumulation. These findings are consonant with the concept that the sympathetic nervous system is involved in immunoregulation.

Animals↗
PubMed1979

Role of prethymic cells in acquisition of self-tolerance.

The sequential character of T-lymphocyte development as it pertains to the stage at which self-tolerance is acquired was investigated. Three phases were studied, defined here as prethymic, intrathymic, and postthymic as determined by the timing of thymus implantation. The model utilized was the temporal pattern of skin graft rejection in thymusless BALB/c nude mice implanted with allogeneic, C57BL/6J, or syngeneic thymuses before or after skin grafting; in some instances, F(1) hybrid spleen cells were also given to newborns or young adults. These experiments in nude mice showed that, (a) self-tolerance could be established despite the absence of the host's own haplotype in the implanted thymus; (b) recently emigrated postthymic cells could already discriminate self from non-self; (c) specific neonatal tolerance could be induced in nudes by inoculation of F(1) hybrid cells; (d) nudes showed a higher capacity for induction of neonatal tolerance than did normal littermates. These findings indicate that the process of self-tolerance in the T cell's lineage begins during the prethymic state early in ontogeny.

Animals↗