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Biomedical subjects

G Costa

Publications and source records attributed to G Costa.

At least 271 records · Page 15Linked to original sources
PubMed1983

Evidence for dopaminergic control of aldosterone in man.

The effect of L-dopa (0.50 g, orally) on serum aldosterone, cortisol and potassium levels, plasma renin activity, and on urinary aldosterone excretion has been studied in normotensive subjects, before and after dexamethasone-induced ACTH suppression. L-dopa caused a further reduction in the levels of aldosterone but not cortisol, in the dexamethasone treated subjects. It is therefore suggested that the inhibitory action of L-dopa on aldosterone secretion is mediated by the dopaminergic system.

Adult↗
PubMed1983

Effects of dopaminergic drugs on cerebellar prostaglandin concentrations.

Previous data indicate that the injection of dopaminergic drugs induces changes in cerebellar 3',5'-guanosine monophosphate (cGMP) content. Accordingly, we have investigated the effects of haloperidol, sulpiride, or apomorphine on cerebellar prostaglandin (PG) concentration, a parameter related to cGMP content. Results obtained show that dopamine receptor blocking agents, such as haloperidol and sulpiride, significantly decrease cerebellar PGE2 and PGF2 alpha concentrations, while opposite changes are induced by apomorphine, a dopamine receptor agonist.

Animals↗
PubMed1983

Treatment of chronic constipation by a bulk-forming laxative (Fibrolax).

Seventy-five patients affected by chronic constipation were treated for 4 weeks with an Ispaghula Husk preparation (Fibrolax), a bulk-forming laxative. Frequency, stool consistency, abdominal pain and signs of venous stasis improved after treatment. No important side-effect was recorded. Cholesterol, HDL-cholesterol and triglycerides did not show significant changes.

Adult↗
PubMed1983

Effect of nimodipine, a new calcium antagonist, on ACTH and corticosterone release "in vivo" and "in vitro".

Intravenous injection of nimodipine (1, 10 and 100 micrograms/Kg) determined a sharp and short-lasting increase in plasma ACTH levels. No change was observed in corticosterone plasma concentration. Intracerebroventricular injection of nimodipine (up to 50 micrograms/rat) did not alter hormone plasma levels. In in vitro experiments, nimodipine (10(-8), 10(-7) and 10(-6) M) did not modify basal and hypothalamic extract-stimulated ACTH release from pituitary tissue, as well as basal release of corticosterone from isolated adrenal glands. However, when adrenal tissue production of corticosterone was stimulated with ACTH, nimodipine (10(-8), 10(-7) and 10(-6) M) showed a powerful and long-lasting inhibitory effect. Data indicate that nimodipine could influence pituitary-adrenal axis by primarily reducing the responsiveness of adrenal glands to ACTH, and exclude a direct effect on hypophysis. It is suggested that the nimodipine-induced reduction of adrenal tissue responsiveness could trigger in vivo a reflex increase in ACTH release, which, in turn, might avoid a decrease in plasma corticosterone levels.

Adrenal Glands↗
PubMed1983

[The lipocorticotropic system and prolactin secretion].

Administration of ACTH beta 1-24 (0.25 mg, i.m.) in six healthy subjects reduces blood prolactin response to sulpiride (100 mg, i.m.). Dexamethasone (2 mg, orally, given at 11.00 p.m. of preceding day) blocks blood prolactin response to insulin-induced hypoglycemia (0.20 U. kg of "Actrapid" Novo, i.v.) in six voluntary healthy subjects. Intravenous naloxone (0.4 mg/Kg of body weight) blocks in man blood prolactin response to insulin-induced hypoglycemia. On the basis of the above data we can hypothesize that ACTH and dexamethasone have influenced by a feed-back mechanism the lypocorticotropic system. Such system by beta-endorphin release can modulate the secretion of prolactin. Thus inhibition of the lipocorticotropic system may be responsible for the reduced response of the prolactin system to stimulation by sulpiride or hypoglycemic stress.

Adolescent↗
PubMed1982

Alpha-naphthyl acetate esterase activity in mouse thymus and other lymphoid organs.

Alpha-naphthyl acetate esterase (ANAE) reaction of mouse and rat thymus cells was studied. The majority of cells demonstrated ANAE in the form of multiple scattered granules. A reaction of this type appeared particularly labile, was found only when smears were fixed in formalin vapours and was inhibited by NaF. ANAE staining of thymus cells from mice of different ages was studied: the percentage of cells with single-spotted ANAE reaction was found to increase with age, while cells with granular scattered activity showed a progressive slight decrease. The percentage of ANAE positive cells in spleen appeared to be lower than in thymus, and showed only minor variations in different ages. In mouse and rat thymus and bowel lamina propria clusters of lymphocytes were found showing a sickle-shaped ANAE reaction, surrounding diffusely stained large cells which, on the basis of cytochemistry and phagocytosis ability, could be identified as macrophages. Analogous cell clusters were found in human tonsils and adenoids. These cell clusters were found to be similar to those formed by Ia-positive interdigitating cells which have been previously observed in human thymus, tonsils and bowel. The role of these clusters in the education process of lymphocytes is discussed.

Aging↗
PubMed1981

Investigations on behavioral effects of an extract of Cannabis sativa L. in the rat.

The behavioral responses of the rat to an extract of Cannabis sativa were examined after IP injection of 5, 15 and 30 mg/kg (expressed as delta 9 tetrahydrocannabinol). The lowest dose of the extract induced stereotyped behavior (rhythmic head movements, intermittent gnawing and sniffing) together with hypersensitivity to stimuli and hyperthermia. The administration of higher doses of the extract resulted, initially, in similar behavioral effects but of greater intensity, followed by a cataleptic state alternating with atonic muscular prostration; rectal temperature was decreased. Pre-treatment with 6-hydoxydopamine (6-OHDA, which produces degeneration of catecholamine-containing nerve terminals)or pimozide (blocker of dopamine receptors) significantly reduced both stereotype and hyperreactivity. Thermic effects were also antagonized by 6-OHDA pre-treatment. Cannabis-induced catalepsy was enhanced by pimozide but reduced by atropine (3 mg/kg SC). These results support the hypothesis that catecholamines play an important role in the complex behavioral effects of cannabis.

Animals↗
PubMed1981

Evidence of a multiplicative effect between cigarette smoking and occupational exposures in the aetiology of bladder cancer.

A case-control study on urinary tract cancer in men is ongoing in the Province of Torino. The analysis of tobacco smoke and occupational histories of the first 225 case-control pairs is described. The overall relative risks (RR) for tobacco smoke and for occupations known to entail a risk for bladder cancer were respectively 4.8 (95% confidence limits (C.L.) 2.4--9.3) and 1.7 (1.0--2.7). There was a clearcut dose-response relationship between different categories of cigarette consumption and risk for urinary tract cancer. For each level of cigarette consumption, relative risks were compared between men reporting and non-reporting occupation at risk. This analysis suggested a multiplicative effect between the 2 factors.

Aged↗
PubMed1981

Clinical parameters related to anorexia.

Caloric intake was studied in 89 cancer patients who recorded diet diaries. Twenty-five percent had caloric intake below their calculated basal energy expenditure (BEE). An additional 45% had caloric intakes between 1.0 and 1.5 x BEE. Patients reported symptoms referable to the oronasal area and the gastrointestinal tract as possible factors in decreased eating. Food intake is controlled by several categories of cues and one or more of these may be altered in cancer patients to decrease caloric intake.

Anorexia↗
PubMed1980

[The dopaminergic system and aldosterone secretion. I. Suppressive effects of L-dopa on secondary hyperaldosteronism].

The authors studied the blood aldosterone, cortisol and kalium levels, the plasma renin activity and the aldosterone urinary excretion following L-DOPA (0.50 g per os) administration in seven patients affected by hypertension and secondary hyperaldosteronism. The results suggest that L-DOPA administration, by stimulating the dopaminergic biosynthesis. Nevertheless such a conclusion needs further investigations.

Adult↗
PubMed1980

[The dopaminergic system and aldosterone secretion. II. Effect of L-dopa and dexamethasone on aldosterone biosynthesis].

The authors studied the blood aldosterone, cortisol, and kalium levels, the plasma renin activity and the aldosterone urinary excretion following L-Dopa (0,50 g per os) administration in five patients affected by hypertension and six healthy control subjects, before and after the CRF-ACTH system suppression. The observed pattern shows that the aldosterone biosynthesis is inhibited also after the CRF-ACTH system has been suppressed. Therefore the authors conclude that the inhibiting action of L-Dopa on the aldosterone biosynthesis is mediated by the dopaminergic system stimulation.

Adult↗
PubMed1980

[Aldosterone production in vitro by angiotensin II: the role of Ca++].

In beef isolated and superfused adrenal glands, the Authors have studied the production of aldosteron and tissue concentration of cAMP during superfusion with angiotensin II alone or preceededby preincubation with indomethacin or verapamil. In such experimental conditions the Authors could evidence that th aldosterone-inductor effect of angiotensin II is not mediated by cAMP but by PGs and Ca++.

Adrenal Glands↗
PubMed1980

[Production of corticosterone in vitro: role of PGE2].

The Authors have studied corticosteron output and tissue levels of cAMP during superfusion with ACTH and/or PGE2 before and after preincubation with indometacin (2 microgram/ml) in beef adrenal glands isolated and superfused with Ringer solution. The Authors on the basis of Mieir studies, conclude that PGE2 can be considered as fixed intermediares of the corticosteroidogenetic action of ACTH.

Adrenal Glands↗
PubMed1980

[Saralasin in subjects with low renin arterial hypertension].

The Authors have studied, in a group of hypertensive subjects with low renin, the behavior of arterial blood pressure, PRA, plasma aldosterone, plasma K and Na, after intravenous load of Saralasin before and after treatment with Furosmide (40 mg orally given for 4 days). In such conditions we evidenced an agonist effect of Saralasin mainly on plasma aldosterone and less on arterial pressure. The Authors conclude that Saralasin, in given conditions (free receptor sites), can exhibit on agonist effect on aldosterone secretion; such agonist effect can be augmented by dopaminergic deficit, that sometimes in present is essential arterial hypertension.

Adult↗