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Biomedical subjects

M Del Tacca

Publications and source records attributed to M Del Tacca.

At least 181 records · Page 10Linked to original sources
PubMed1982

The effect of pirenzepine on gastric acid secretion and gastrin release induced by bombesin and meal in the dog.

Pirenzepine exerted a powerful inhibitory effect on gastric acid secretion from both the gastric fistula and the Heidenhain pouch of the dog, following intravenous infusion of bombesin. Similar results were obtained from the Heidenhain pouch when hypersecretion was stimulated by the meal test. The rise in plasma levels of radioimmunological gastrin, obtained by either bombesin or food administration, was not significantly affected by pirenzepine. The overall results indicate that the inhibitory effect of pirenzepine on gastric acid secretion in the dog was independent from the release of endogenous gastrin.

Animals↗
PubMed1981

The effects of drugs on pacemaker regions of isolated rabbit renal pelvis.

Acetylcholine failed to change the frequency of spontaneous contractions in the proximal region of isolated rabbit renal pelvis, but significantly increased the contractile frequency in the middle and distal regions, which then reached similar levels to those of the proximal region. Pretreatment with reserpine caused a decrease in the frequency of spontaneous contractions in the proximal, but not in the middle or distal regions. Reserpine-pretreated tissues developed hypersensitivity to catecholamines, while acetylcholine produced effects similar to those observed in control preparations. Atropine and N-methyl-scopolamine antagonized the action of acetylcholine in both the middle and the distal regions, suggesting that the action was exerted through muscarinic receptors. Adrenaline and alpha-stimulating drugs, but not isoprenaline, significantly increased the contractile frequency of all three tissues: the increase in the proximal region reached levels in excess of its fundamental maximal frequency. Phentolamine caused a significant decrease in the frequency of the proximal region and fully inhibited the stimulating action of catecholamines, indicating that this stimulation was mediated by alpha-adrenoceptors. The myogenic nature of pacemaking cells was confirmed by the effect of tetrodotoxin, ouabain and verapamil. The decrease in frequency in the pacemaker region of the proximal pelvis whether caused by reserpine or phentolamine indicates a significant role of catecholamines in modulating pacemaker activity.

Acetylcholine↗
PubMed1981

Noradrenaline and alpha blockers in daunomycin cardiotoxicity.

The total tissue noradrenaline content of the heart from daunomycin acutely treated guinea pigs has been found to be significantly increased compared with controls. Under the same treatment, electrocardiograms showed the occurrence of alterations of electrical waves, consisting of a decrease and reversion of T waves, or an increase in their voltage. Pretreatment with alpha blocking drugs nicergoline and yohimbine failed to protect the animals from daunomycin cardiotoxicity.

Adrenergic alpha-Antagonists↗
PubMed1980

Phenobarbital prophylaxis of post traumatic epilepsy.

Phenobarbital (PB) was tested for its efficacy in averting post-traumatic epilepsy (PTE) in patients with non-missile head injuries. The protocol envisaged the administration of PB throughout a period of two years in randomly assigned doses ranging from 0.5 to 1.5 and from 1.6 to 2.5 mg/kg/day. The study included neurologic examination, EEG and plasma PB levels. Ninety patients, 83 of whom with serious head injury followed the prescribed treatment for the entire period. Two adult patients manifested seizures 5 and 10 months after the trauma. They were being treated with doses over 1.5 mg/kg/day. Another patient had a seizure six months after the end of the prophylaxis. Low doses of PB and monitoring permitted a reduction of side effects. The low incidence of PTE indicates that PB has an efficient prophylactic effect. The results also show that a low dosage has a favourable effect.

Adolescent↗
PubMed1980

[Paraquat poisoning; clinical toxicological aspects and a case description].

The clinical course of a young woman following the ingestion of the herbicide Paraquat in a suicide attempts is reported. Clinical signs of intoxication consisted at first in alterations of hepatic and renal functions, and later in progressive pulmonary failure. The patient died in severe respiratory distress on the 8th day due to cardiac arrest, probably anoxic. Treatment was initially on standard lines, with cathartics with the aim to prevent the absorption of Paraquat in the plasma and its accumulation in the lungs. In addition, high doses of steroids, immunosuppressive agents, prophylactic antibiotics and cardiotonics were given. Peritoneal dialysis and haemodialysis were concomitantly assured. The Authors suggest that in Paraquat poisoning an adequate therapeutic treatment could consist in specific sorbents such as Fuller's earth and bentonite, haemoperfusion over a coated charcoal system or cation exchange resins. Administration of drugs such as corticosteroids, immunosuppressants (bleomycine) and the enzyme superoxide dismutase may be also indicated. On the contrary, oxygen therapy should be carefully monitored: in fact hyperoxic atmospheres, by increasing the rate of generation of superoxide radicals, enhance cellular toxicity of Paraquat.

Adolescent↗
PubMed1979

Conformational effects on the activity of drugs. 7. Synthesis and pharmacological properties of 2-(p-nitrophenyl)-substituted morpholines.

A series of 1-(p-nitrophenyl)-2-aminoethanol derivatives and their morpholine analogues have been synthesized and pharmacologically investigated in order to confirm some pharmacological observations made with the N-isopropyl-substituted compounds. In agreement with the previously obtained results, the weak alpha-adrenergic-stimulating activity and the potentiating effect on the responses to norepinephrine found in the open-chain compounds persist in their corresponding semirigid cyclic analogues. The results are discussed in the light of common knowledge of the structure-activity relationships of alpha-adrenergic drugs.

Adrenergic alpha-Antagonists↗
PubMed1978

Acetylcholine content of and release from isolated pelviureteral tract.

Measurements were taken for the acetylcholine content of animal and human pelviureteral muscle and for the release of acetylcholine at rest and during field stimulation of the isolated renal pelvis and ureter. Release was frequency-dependent, with the maximum output obtained at 10 Hz. The release of acetylcholine from reserpine-pretreated and piperoxan-treated tissues remained unchanged, but tetrodotoxin (1.10(-6) g/ml) and noradrenaline (2.10(-6) g/ml) significantly reduced the output.

Acetylcholine↗
PubMed1978

The inhibitory action of ketamine on the rat's gastric secretion.

Ketamine exhibited effects on gastric acid secretion total acidity and acid output. Reduction of secretion by ketamine did not appe,r to be significantly different from values obtained with atropine or hexamethonium. In addition to atropine- and hexamethonium-like effects, ketamine also appeared to decrease gastric secretion through a potentiating activity on the sympathetic nervous system. When sympathetic activity was potentiated by cocaine, the antisecretory effect of ketamine appeared to be significantly reduced, compared with that of atropine. Furthermore, after alpha- or alpha- and beta-blockade, ketamine produced similar decreases in secretion, although maximum inhibitory effect was obtained after beta-blockade. Potentiation of adrenergic activity by ketamine seemed to be mediated through alpha-receptors. Histamine H2 receptors did not appear to be involved in the antisecretory action of ketamine.

Animals↗
PubMed1975

Conformational effects on the activity of drugs. 5. Pharmacological properties of 2-(p-nitrophenyl)-4-isopropylmorpholine, a cyclic analog of INPEA.

2-(p-Nitrophenyl)-4-isopropylmorphine (V), an analog of 1-(p-nitrophenyl)-2-isopropylaminoethanol (INPEA, I) in which the OCHCHN chain of I is locked in a morpholine ring, loses the beta-receptor blocking activity of I on various isolated preparations. The same ineffectiveness is observed in the O-methyl (II), N-methyl (III), and N,O-dimethyl analog (IV) of I. However, some other properties which are present in I, such as inhibitory effect on acetylcholine or on 5-HT, intrinsic alpha-sympathomimetic activity, and potentiation of catecholamines, are maintained; this demonstrates a complete dissociation of these effects from beta-receptor blockade. The interactions with the alpha-adrenoceptors and with the uptake mechanism are discussed on the basis of the structure-activity relationship between I and its analogs II-V.

Animals↗
PubMed1973

Some observations on the intrinsic nervous mechanism in Hirschsprung's disease.

Both at rest and during transmural stimulation acetylcholine output from isolated longitudinal and circular muscle strips is significantly higher in the spastic segment than in the proximal dilated bowel. No difference has been found in the tissue concentration of acetylcholine between ganglionic and aganglionic specimens. The pattern of response to transmural stimulation is also similar in the spastic and dilated bowel. However, after cholinergic and adrenergic blockade transmural stimulation fails to induce relaxation in aganglionic specimens, as it does in normal colon. The hypotheses are advanced that the increase in acetylcholine output may be partly dependent on a failure of the intrinsic modulating mechanisms and that an alteration of the non-adrenergic inhibitory neurons may be involved in the motor disturbances of the aganglionic tract.

Acetylcholine↗