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Biomedical subjects

P Deschaux

Publications and source records attributed to P Deschaux.

18 recordsLinked to original sources
PubMed1992

In vitro effects of substance P and somatostatin on lymphoproliferation in rainbow trout (Salmo gairdneri).

Lymphocytes from peripheral blood of rainbow trout are put in the presence of increasing concentrations of substance P (SP) and somatostatin (SOM). We have shown that SP stimulates and SOM inhibits lymphoproliferation and that the effects are dose dependent. These results suggest that SP and SOM receptors may exist on fish peripheral blood lymphocytes. When cells are stimulated by PHA or LPS, the presence of SP enhances the response to PHA whereas it only modifies the response to LPS to a slight extent. The presence of SOM inhibits PHA- or LPS-induced stimulation. The inhibition of the proliferation is higher in the case of LPS-stimulated cells. These results suggest that there is an unequal distribution of neuropeptide receptors among the various lymphocyte subpopulations.

Animals↗
PubMed1991

Antibody responses of mice exposed to low-power microwaves under combined, pulse-and-amplitude modulation.

Irradiation by pulsed microwaves (9.4 GHz, 1 microsecond pulses at 1,000/s), both with and without concurrent amplitude modulation (AM) by a sinusoid at discrete frequencies between 14 and 41 MHz, was assessed for effects on the immune system of Balb/C mice. The mice were immunized either by sheep red blood cells (SRBC) or by glutaric-anhydride conjugated bovine serum albumin (GA-BSA), then exposed to the microwaves at a low rms power density (30 microW/cm2; whole-body-averaged SAR approximately 0.015 W/kg). Sham exposure or microwave irradiation took place during each of five contiguous days, 10 h/day. The antibody response was evaluated by the plaque-forming cell assay (SRBC experiment) or by the titration of IgM and IgG antibodies (GA-BSA experiment). In the absence of AM, the pulsed field did not greatly alter immune responsiveness. In contrast, exposure to the field under the combined-modulation condition resulted in significant, AM-frequency-dependent augmentation or weakening of immune responses.

Animals↗
PubMed1979

Effects of low level microwave radiation on the digestive transit of the rat.

The effects of low level microwave radiation (3-4 mW/cm2--2450 MHz) during 4 and 8 h on the WISTAR Rat digestive transit has been studied. The results showed no effect after 4 h radiation and an acceleration of the digestive transit after 8 h of radiation (p less than .001). The acceleration of the digestive transit was still observed after 24 h (p less than .001). 60-90 s after radiation time the rectal temperature of radiated animals did not differ from the controls.

Animals↗
PubMed1979

Endocrine interaction of the thymus with the hypohysis, adrenals and testes: effects of two thymic extracts.

The concentration of ACTH, corticosterone, LH and testosterone in the plasma of rats have been measured in normal, thymectomized and sham-operated rats. A group of rats, thymectomized at birth, received two i.p. injections weekly of two thymic extracts, each prepared in a separate way. Neonatal thymectomy was followed by the appearance of a transitory wasting disease during which a hormonal unbalance was manifest. Plasma corticosterone and ACTH levels increased at first at 30 days after thymectomy and then decreased at 60 days. The levels of the different hormones returned to normal by 90 days. The injections of thymic extracts rectified all these perturbations. The plasma levels of testosterone and corticosterone of hypophysectomized rats were compared to those of hypophysectomized and thymectomized animals. Results suggested that the thymus has a direct action of the adrenal cortex and in indirect action on the testes. The indirect effect is probably mediated through the hypophysis.

Adrenal Glands↗
PubMed1978

[Endocrine interrelationships of the thymus (author's transl)].

We have studied the interrelation between the thymus and the hypophyso-adrenal and hypophyso-testicular axes in male rats. In the first part of our work, we have essayed the plasma levels of testosterone, LH, corticosterone and ACTH in neonatally thymectomized or thymectomized and hypophysectomized animals. The results obtained allow us to conclude that there is an indirect action (via hypophysis) of the thymus on the testes and a direct action on the adrenals by the intermediary of one active extract. In the second part of our study we measured hormonal activity of the thymus in hypophysectomized or adrenalectomized or orchidectomized rats. The results obtained show that there is no effect of the testes on the thymus secretion; on the other hand the thymus is under the control of hypophysis and adrenals.

Adrenal Cortex↗
PubMed1976

[Karyometry of thymic reticular cells in the rat. Effect of hydrocortisone and adrenalectomy].

A new process in taxinomic analysis clearly confirmed the presence of three different types of cells (epithelial, hypertrophic and mesenchymal) in the reticular zone of the thymus. The injection of hydrocortisol as well as adrenalectomy induced specific changes in nuclear surfaces of three cell types, while hydrocortisol tented to increase the surface of epithelial and mesenchymal cells, adrenalectomy reduced it, while a modification was seen in the percentages relative of the cell types. In adrenalectomized animals, the effect result was counteracted by injections of hydrocortisol.

Adrenalectomy↗
PubMed1975

[Hypothalamo-hypophysial-thymic axis in the rat].

Thymic extracts, with proved immunologic properties, decrease, in vitro, RNA and DNA synthesis of hypothalamic fragments of adult rat and have no effect on hypophysis culture; we found a similar action in vivo. Growth hormone inhibits the nucleic acids synthesis of thymic fragments; no action is found with hypothalamic extracts. Hypothesis, that thymic activity is dependent on hypophysis with retroaction on hypothalamus, is discussed.

Animals↗
PubMed1975

[Effect of neonatal thymectomy on the content of magnesium in the plasma and in various tissues of the rat].

White rats were thymectomized neonatally. After 60 days, no alteration was noted in the plasma or testis magnesium level. On the other hand, a marked decrease was observed in the magnesium content of muscle (-23%) and of bone (-19%). The injection of thymosin reversed these changes. These findings suggest that a correlation between the thymus and the muscle is exerted by a protein factor (thymosin), and that the thymus may act on sex glands through an indirect pathway.

Animals↗