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Biomedical subjects

G Soldani

Publications and source records attributed to G Soldani.

At least 91 records · Page 5Linked to original sources

Mast cell histamine release induced by doxorubicin and the inhibitory effect of fructose 1,6-diphosphate.

Doxorubicin (DXR) (10(-4) mol/l) causes histamine release from isolated rat mast cells. At lower doses (range 10(-8) mol/l-10(-5) mol/l) the drug failed to evoke secretion. In the 10(-5) mol/l-10(-4) mol/l range there is a significant decrease of the ATP intracellular levels. Fructose 1,6-diphosphate (FDP) produced a sharp increase of the ATP content of the DXR treated cells. In particular, FDP pretreatment inhibited the DXR stimulated histamine release.

Adenosine Triphosphate↗

The pharmacokinetics of clofoctol in healthy neonates and adults studied by an original HPLC technique.

The pharmacokinetics of clofoctol [(tetramethyl-1,1,3,3,butyl)-4-(dichloro-2,4-benzyl)-2-hydroxy-1-benzene ] was investigated in six healthy newborns and compared with the kinetic parameters of the drug in six healthy adults. The concentration of the drug in plasma was measured by means of an original sensitive HPLC technique. In both neonates and adults treated rectally with clofoctol, the plasmatic peak occurred at the 30th min, although the maximal peak of adults was significantly lower. Kel and T1/2 exhibited a similar pattern, whereas the AUC was about 5 times higher in newborns. The present findings suggest that clofoctol is well absorbed rectally. The higher plasmatic levels of clofoctol in neonates may result from their lower degree of hepatic metabolic activity.

Adult↗

Pharmacological studies on the mechanisms underlying the inhibitory and excitatory effects of clonidine on gastric acid secretion.

The effects of clonidine on gastric acid secretion were investigated using various pharmacological preparations both in vivo and in vitro. In conscious pylorus-ligated rats clonidine produced a marked reduction of gastric secretion which was prevented by yohimbine, while in anesthetized pylorus-ligated rats the drug failed to affect gastric secretion. In stomach lumen-perfused rats, insulin-stimulated secretion was inhibited by clonidine; in contrast, the drug markedly potentiated bethanechol-evoked gastric secretion; this increase was fully prevented by cimetidine. In isolated preparations of guinea-pig gastric fundus, both spontaneous and bethanechol-induced hypersecretion were significantly enhanced by clonidine; this enhancement was also inhibited by cimetidine. The release of acetylcholine, measured at rest and during vagus nerve stimulation of both guinea-pig and rat isolated stomachs, was significantly inhibited by clonidine: this effect was prevented by yohimbine. Overall results indicate that clonidine possesses both inhibitory and excitatory effects on gastric acid secretion. The inhibitory effect appears to be mediated through the activation of presynaptic alpha 2-receptors which modulate acetylcholine release from the vagus nerve, while the excitatory action seems to depend on histamine-like properties of the drug.

Acetylcholine↗

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↗

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↗

The pharmacokinetics of two erythromycin esters in plasma and in saliva following oral administration in humans.

An improved highly sensitive fluorimetric methods has been employed to measure plasma and saliva levels of erythromycin propionate and stearate in eight healthy volunteers following a single oral dose of 7.5 mg/kg. The plasma curves exhibited a mean half-life of 5.22 +/- s. e. m., 0.86 h-1 for the propionate and 2.97 +/- 0.22 h-1 for the stearate. Peak levels were reached at the 2nd h (4.07 +/- 0.29 microgram/ml for the propionate; 2.15 +/- 0.14 microgram/ml for the stearate). The area under the total plasma concentration curve was about 3-fold higher in the case of propionate. The concentration in saliva was about 20% of the corresponding concentration in plasma for the propionate and about 25% for the stearate. A significant positive correlation was observed between plasma and saliva levels for both macrolides.

Administration, Oral↗

[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↗

Polymyxin B-induced oedema in hind paw of the rat as an assay for antiinflammatory drugs.

A method is presented for measuring the volume of the oedema induced by intraplantar infection of polymyxin B, a polyenic antibiotic, in the hind paw of the rat. Peak values of the oedema reached the maximum within 30 min to 1 h after injecting the drug and decreased with time until the 24th h, when it had almost disappeared. The phlogogenic effect of polymyxin B seems to be related to that induced by serotonin and histamine, rather than to the reaction provoked by carrageenin or prostaglandins. The oedema was inhibited by pretreating the animals p.o. with both steroidal and non-steroidal antiinflammatory agents. The inhibitory effect of antiinflammatory drugs was found to be dose-dependent.

Animals↗

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↗

[Anesthesiological problems in renal transplantation].

The physiopathological changes observed in uraemia are briefly described and an account is given pharmacological considerations relevant to the induction and maintenance of anaesthesia and muscle relaxation, The anaesthesiological management of 20 kidneys transplants (17 from living donors and 3 from cadavers) is explained. Steps taken for intra-operative care and protection of the transplanted organ to aid its function recovery are explained.

Acidosis↗

Effects of gonadotropin-releasing hormone (GnRH) on gastric secretion and gastrin release in the dog.

The effects of GnRH on gastric secretion and gastrin release from dogs provided with gastric fistulae and Heidenhain pouches have been investigated. A transient yet significant inhibition of pentagastrin-stimulated secretion from gastric fistulae was observed, while secretion from Heidenhain pouches was unchanged. The maximal inhibitory effect of GnRH on both acid and pepsin secretion stimulated by 2-deoxy-D-glucose was obtained from gastric fistulae. On the contrary, GnRH failed to affect either acid secretion stimulated by bethanechol or acid secretion and gastrin release induced by bombesin. The present results indicate that GnRH possesses an inhibitory action on gastric secretion from the vagally innervated stomach of the dog. The most likely inhibitory mechanism seems to be represented by a decrease of the vagal activity.

Animals↗

Effects of galanin on smooth muscle and mucosa of porcine jejunum.

The enteric neuropeptide galanin (GAL) increased the amplitude of spontaneous contractions in longitudinally oriented muscle strips and inhibited short-circuit current (Isc) elevations induced by transmural electrical stimulation (ES) of mucosal sheets from porcine jejunum in vitro. GAL-induced contractions (GAL EC50 = 9 nmol/l) were maximally 25% of those elicited by 10 mumol/l carbamylcholine and remained unaffected by atropine, tetrodotoxin, or tachyphylaxis to substance P. The presynaptic Ca2+ channel blocker, omega-conotoxin (0.1 mumol/l), inhibited GAL-induced contractions by 66%. GAL attenuated mucosal Isc elevations induced by ES with an IC50 = 13 nmol/l and at 0.1 mumol/l produced rapid decreases in basal Isc averaging 8 +/- 2 microA cm-1 in 77% of tissues examined. The alpha-adrenoceptor blocker phentolamine or the opiate antagonist naloxone did not alter tissue Isc responses to GAL. These results suggest that GAL modulates neuronal activity linked to secretomotor function in the porcine small intestine.

Animals↗