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Biomedical subjects

N Fabris

Publications and source records attributed to N Fabris.

At least 127 records · Page 7Linked to original sources
PubMed1980

Thymus-endocrine interactions during ageing.

The hypotesis of the thymus acting as biological clock for ageing is revisited. On the basis of data on the endocrine action of the gland, the age-dependent involution of the thymus is postulated to play a fundamental role on the deterioration of the immunological as well as the endocrine functions. Data either on beta-adrenergic responsiveness to Isoproterenol or on hormonal balance, tested on animal model with different degree of thymus efficiency, support this hypothesis.

Aging↗
PubMed1978

Age-dependence of isoproterenol-induced DNA synthesis in submandibular glands of BALB/c mice.

The age-dependency of isoproterenol (IPR) induced DNA synthesis was investigated in different organs of Balb/c mice. Although modifications of the physiological rate of DNA synthesis after IPR injection occurred also in liver and spleen, a quasi-linear decrease of the peak of IPR response with advancing age was observed only in submandibular glands. Such a decrease was observed when animals were injected with 10(-4) g IPR per g body weight, lower doses being unable to discriminate between young and old mice. In spite of some differences between mice and rats, the early appearance and linearity of the age-dependency remain common features of IPR response.

Age Factors↗
PubMed1978

Thymus-dependent reversibility of physiological and isoproterenol evoked age-related parameters in athymic (nude) and old normal mice.

In order to assess the relationship between the thymus and aging processes, a linear age-dependent parameter in mice such as the response of the submandibular gland to an injection with isoproterenol has been evaluated in athymic (nude) and thymectomized Balb/c mice. The IPR-induced DNA synthesis is reduced in both experimental groups when compared to untreated normal littermates and is recovered by grafting a neonatal thymus. Moreover, the impairment of IPR response in old animals is recovered to young levels by grafting one neonatal thymus one month before test. Neonatal thymus grafts in old recipients are also able to correct their abnormal serum levels of triiodothyronine and insulin. The influence of neonatal thymus on such non-immunological and age-related parameters suggests that this gland can control aging processes, probably through its implication with the endocrine system.

Age Factors↗
PubMed1977

Differential effect of pregnancy or gestagens on humoral and cell-mediated immunity.

The reactivity of spleen lymphocytes in a mixed lymphocyte culture and the in vivo PFC response to sheep erythrocytes have been evaluated in pregnant female mice and data compared with those observed in virgin sexually mature female mice daily treated either with progesterone or human chorionic gonadotropin (HCG) or human prolactin. The mixed lymphocyte reactivity is depressed at mid-pregnancy, whereas PFC response is increased. Comparable immunological modifications have been found in mice treated with HCG, but not in animals treated with progesterone or prolactin. The similarity between HCG treatment and pregnancy suggests that the rate of gonadotropin release may be one of the earliest events responsible for the immunological disturbances present during pregnancy, although its action on the lymphoid system seems to require the presence of the ovary. From these data and from the observation that HCG increases the PFC response also in thymusless nude female mice, it can be deduced that it acts on both T and B cells.

Animals↗
PubMed1977

Differential effect of pancreatectomy on humoral and cell-mediated immune responses.

Cell-mediated immune reactions, such as allogenic skin-graft rejection and PHA or MLC responses, and antibody synthesis against different antigens (sheep erythrocytes, Brucella antigen, bovine serum albumin) have been evaluated in rats suffering from experimentally-induced diabetes and in age-matched sham-treated controls. Cell-mediated immune reactions are strongly depressed diabetic rats. The cellularity of the thymus and of thymus-dependent areas and the number of peripheral blood lymphocytes is significantly reduced in pancreatectomized rats. Moreover, the immunological recovery from heavy cortisonization is also greatly impaired. Daily treatment with insulin may prevent these immunological alterations. By contrast, antibody responses in diabetic rats are not quantitatively altered in respect to either the number of antibody producing cells in the spleen or the circulating antibody titres. The discrepancy between the abnormality of cell-mediated immune reactions in diabetic rats and their physiological capacity to synthetize antibodies suggests that the sensitivity to an insulin-deprived environment is present only in a definite, although yet undefined, subpopulation of lymphoid cells rather than in the whole lymphoid system.

Animals↗
PubMed1975

Relation of lymphoid system and hormones to aging.

Congenital deficiencies of developmental hormones, such as growth hormone and thyroxine, are responsible for the thymus-dependent immunodeficiency disease observed in dwarf mice. Such an immunodeficiency state is associated with early aging phenomena. This fact suggests that lymphoid cells and primarily T-derived cells are involved in the control of aging processes.

Adrenal Glands↗