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Biomedical subjects

J Besson

Publications and source records attributed to J Besson.

At least 55 records · Page 3Linked to original sources
PubMed1980

Effect of steroids on vasoactive intestinal peptide in discrete brain regions and peripheral tissues.

The effect of castration and adrenalectomy was studied on vasoactive intestinal peptide (VIP) concentrations in various brain and peripheral structures of male rats. Castration has no effect on any of the structures studied, whereas 4 weeks adrenalectomy (ADX) decreases VIP concentrations in the hippocampus and increases them in the adenohypophysis, two structures known to contain large amounts of glucocorticoid receptors. Corticosterone administration restores VIP levels to control values only in the dorsal hippocampus. In contrast, dexamethasone counteracts both the decrease and the increase of VIP concentrations obtained after ADX in the hippocampus and in the adenohypophysis respectively. The present results suggest that corticosteroids can be involved in the regulation of VIP actions both in the brain and in the adenohypophysis.

Adrenalectomy↗
PubMed1979

Vasoactive intestinal peptide inhibits release of somatostatin from hypothalamus in vitro.

The effect of vasoactive intestinal peptide (VIP) was studied on the release of somatostatin (SRIF) from slices of several regions of the rat brain in vitro. VIP induced a dose-dependent inhibition of SRIF release from mediobasal hypothalamic slices but did not interfere with SRIF release from preoptic area, amygdala or cortex. VIP inhibition had an apparent affinity: Kd = 6.8 +/- 3.9 x 10(-11) M. Secretin had a similar effect but at 600-fold higher concentrations (Kd secretin = 4.2 +/- 0.6 x 10(-8) M). Gucagon was ineffective in concentrations ranging from 10(-10) M to 10(-7) M. The data are consistent with a role of VIP in the hypothalamic control of growth hormone secretion.

Animals↗
PubMed1979

[Vasoactive intestinal peptide (VIP): specific receptors and adenylate cyclase activation in a human prolactin-secreting pituitary tumor].

Receptors for the Vasoactive Intestinal Peptide (VIP) were characterized in particles enriched in plasma membranes obtained from a human prolactin-secreting pituiatry tumor. Native VIP inhibited competitively the binding of 125I-VIP to the particles and stimulated cyclic AMP production; both these effects were observed at concentrations of VIP as low as 10(-11)-10(-10) M, which are compatible with VIP concentrations in the hypothalamopituitary portal blood.

Adenylyl Cyclases↗
PubMed1979

Study of urinary excretion of butobarbitone in man in relation to the percentage of ideal body weight.

1 Thirty-three patients with no evidence of endocrine disease, hepatic or renal insufficiency or sleep disorders, were classified in groups 1 to 4 in order of increasing of percentage of ideal body weight (IBW) respectively: less than 90% of IBW, 90--120%, 120--180%, and greater than 180% of IBW. After oral administration of 200 mg butobarbitone, concentration of the intact drug was measured by gas liquid chromatographic assay in urine samples collected during 72 h and at three times in blood. 2 A highly significant negative relationship was found between the cumulative excretion of butobarbitone with urine and the logarithm of the percentage of IBW. In contrast for a given weight, excretion of the drug with urine was found to be weakly correlated with the diuresis. 3 The cumulative urinary elimination of butobarbitone was significantly different between the groups studied, except of the difference between the group 2 and 3 of the patients. No significant difference was found between the renal clearances of butobarbitone in the four groups of subjects. 4 We conclude that redistribution of butobarbitone into adipose tissues can explain the obtained results and that obesity modifies the pharmacokinetics of the drug.

Adult↗
PubMed1977

[Intestinal vasoactive peptide receptors in enterocytes : specific binding and stimulation of cyclic AMP].

Receptors for the vasoactive intestinal peptide (VIP) were characterized on enterocytes isolated from Rat small intestine. Native VIP inhibited competitively the binding of 125I-VIP to enterocytes and strongly stimulated cyclic AMP production; both these effects were observed for concentrations of VIP as low as 0.5-1.0 ng/ml (0.15-0.30 nM) which are compatible with the VIP concentration in the gut.

Animals↗
PubMed1977

[The topology of circular DNA].

A non-orientable structure, said Möbius stripe, is proposed for certain types of circular DNA. This structure could account for particular forms, such as dimers, double length molecules, or catenans which are molecules topologically interwomen. On the other hand, it is suggested that a second structure derived from the same principal of non-orientability could have gendered the dynamics of DNA replication at the origin of life: this is hypothesis of archetype Möbius strip.

Biological Evolution↗
PubMed1975

[Acute non-tuberculous military lung].

The authors report the case of a young woman with acute miliary appearance of the lung with asphyxia, from which she rapidly recovered. No cause was demonstrated; this illustrates the difficulty in diagnosis of this disease. Contact with a bird, led the authors to consider exogenous, allergic granulomatosis, but immunological examinations did not confirm this. Apart from tuberculosis, almost 50 different pathogenic organisms may cause acute respiratory failure associated with a miliary or reticulo-nodular appearance of the lung. The main methods of diagnosis are discussed in relation to the most commonly observed causes in France.

Acute Disease↗