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Biomedical subjects

A Castellucci

Publications and source records attributed to A Castellucci.

18 recordsLinked to original sources
PubMed1992

Effect of endothelin (ET)-1, ET-3 and ET-(16-21) on the isolated and perfused rat kidney from normotensive and spontaneously hypertensive rats.

We have investigated the effect of endothelin (ET)-1, ET-3 and ET-(16-21) on isolated and perfused rat kidney (IPK). ET-1 and ET-3 produced a similar dose-dependent increase in perfusion pressure of IPK, while ET-(16-21) was completely inactive. The ET-1 effects were greater in spontaneously hypertensive rats (SHR) as compared to normotensive rats (WKYR), whereas the ET-3 effects were greater in the SHR group only at the lowest doses. The pressure response of IPK induced by ET-1 was partially modified by prior application of the nitric oxide synthetase inhibitor L-nitroarginine in both WKYR and SHR.

Animals↗
PubMed1992

[Carnitine metabolism in chronic kidney failure].

Carnitine plays an important role in regulating the flow of energetic substrates and their balance through cellular membranes. Usually in chronic renal failure, increased plasma levels of carnitine are found. In early hemodialysis a slow decrease of the muscle concentrations of carnitine is found, followed by a decrease of plasma concentrations long after substitutive treatment. Several signs and symptoms are attributable to carnitine deficiency. It is reported that these changes regress with suitable supply of intravenous carnitine after dialysis end for 15-30 days, and subsequently with chronic administration in the dialysis fluid.

Carnitine↗
PubMed1990

[Subjectivity in interpretation of radiographs in endodontics].

This research found a substantial interobserver disagreement existing in endodontic success/failure interpretation from periapical radiographs. The diagnostic variability appears to be independent of the anatomic location of the endodontically treated tooth (even though it seems less for mandibular teeth), as well as it appears to be independent of the time interval between post-operative and recall radiographs. Extremely significant has also been the fact that an important percentage of observers have contradict themselves in the interpretation of the same radiograph.

Adult↗
PubMed1989

Calcitonin gene-related peptide in the rat kidney: occurrence, sensitivity to capsaicin, and stimulation of adenylate cyclase.

The occurrence, effects and sensitivity to capsaicin and stimulation of adenylate cyclase of calcitonin gene-related peptide (CGRP) in the rat kidney have been investigated. CGRP-like immunoreactivity was higher in the medulla than in the papilla and the cortex. Capsaicin pretreatment significantly reduced CGRP-like immunoreactivity in the medulla and papilla while a small reduction was found in the cortex. CGRP-immunoreactive nerve fibres were observed surrounding blood vessels and occasionally in the vicinity of renal tubules and between the collecting ducts in the papilla. Some CGRP-immunoreactive fibres were also seen in kidneys from capsaicin-pretreated rats. Infusion of capsaicin (1 microM) through the renal artery of isolated and perfused rat kidney increased the CGRP-like immunoreactivity outflow from the venous effluent. This effect exhibited desensitization at the second challenge with the drug. Infusion of either capsaicin (1 microM) or CGRP (1 microM) reduced the increase of perfusion pressure induced by norepinephrine in isolated perfused rat kidney. Plasma protein extravasation was studied in the various regions of the rat kidney following infusion of capsaicin. No significant change was observed in the medulla, papilla or cortex after capsaicin administration. Adenylate cyclase activity was studied in membrane preparations from cortex, medulla and papilla of rat kidney. Cortical and medullary adenylate cyclase was stimulated in a concentration-dependent manner by salmon calcitonin, rat calcitonin and rat CGRP. Salmon calcitonin in these two areas showed half-maximal effective concentration approximately 1000 times lower and maximal stimulation only slightly higher than those of rat calcitonin and rat CGRP. However, in the papilla, only rat CGRP was able to induce a 60% increase of enzyme activity (half-maximal effective concentration, 19 +/- 1.6 nM). It is concluded that CGRP contained in capsaicin-sensitive sensory nerve may exert a local function in discrete areas of the rat kidney.

Adenylyl Cyclases↗
PubMed1988

[Schilder technic].

Explore the source record for details and available documents.

Dental Pulp Cavity↗
PubMed1988

Resolution and pharmacological properties of the enantiomers of the potent alpha-adrenoceptor antagonist 1-[2-ethoxy-2-(3'-pyridyl)ethyl]-4-(2'-methoxy-phenyl)piperazine.

Resolution of the optical isomers of the alpha-adrenoceptor antagonist IP-66 (1-[2-ethoxy-2-(3'-pyridyl)ethyl]-4-(2'-methoxy-phenyl)piperazine) and its intermediate IP-30 (1-[2-hydroxy-2-(3'-pyridyl)ethyl]-4- (2'-methoxy-phenyl)piperazine have been carried out. Optical purity was assayed by high-pressure liquid chromatography. The antagonistic potencies of racemic mixtures and stereoisomers toward phenylephrine- and norepinephrine-induced contraction in isolated rat aortic strips have been compared. (+)-IP-66 and (+)-IP-30 were resp. 363 and 170 times more potent than respective (-) isomers in eliciting competitive alpha 1-adrenoceptor blockade. Similarly IP-66 (+) or (+/-) were extremely more effective than the (-) isomer in antagonizing norepinephrine-induced pressor responses in pithed rat.

Adrenergic alpha-Antagonists↗
PubMed1985

Effects of 1-[2-ethoxy-2-(3'-pyridyl)ethyl]-4-(2'-methoxyphenyl)piperazine (IP-66), prazosin, yohimbine and dihydroergotoxine mesylate on the vasoconstriction of rat mesenteric artery induced by electric stimulation and exogenous norepinephrine.

The effect of (1-[2-ethoxy-2-(3'-pyridyl)ethyl]-4-(2'-methoxy-phenyl)piperazine (IP-66) on the contraction of rat mesenteric artery induced by electric stimulation (ESV) or by injection of norepinephrine (NESV) was compared with the effects of prazosin, yohimbine and dihydroergotoxine mesylate (DHEM). Interference of propranolol on the effects of the 4 alpha-blockers was also considered. Prazosin has proved to be the strongest antagonist of alpha 1-receptors towards which, however, it showed a certain bond latency. In particular conditions related to increased perfusion time and concentrations prazosin also seemed to lose selectivity towards alpha 1-receptors. It was observed that yohimbine is a weak postsynaptic antagonist whereas DHEM showed scarce selectivity. IP-66 proved to be a strong postsynaptic antagonist with negligible presynaptic effect. It was not as strong as prazosin but its bond with alpha 1-receptors appeared more rapid and steady. Results obtained with prazosin or DHEM and propranolol seemed to suggest an equilibrium between beta 2- and alpha 1-receptors shifted towards the latter.

Animals↗
PubMed1979

Lack of hypotensive and brain catecholamine depleting effects by erythro- and threo-alpha-methyl DOPS.

An investigation was carried out to ascertain whether erythro- and threo-alpha-methyl-dihydroxy-phenyl-serine were able of depleting cerebral and peripheral norepinephrine (NE) through their metabolization to alpha-mNE. The results show that the alpha-methyl-aminoacids were decarboxylated only at the periphery and that the threo-form caused depletion in cardiac NE. In any case, both isomers were unable to cross the blood-brain barrier leaving the cerebral NE unaffected. Consequently the use of alpha-mDOPS as alternative tool to alpha-mDOPA in the therapy for hypertension seems unlikely to occur. The results also provide evidence for differences in the pharmacokinetics of the two isomers.

Animals↗
PubMed1976

Role of histidine-decarboxylase inhibitors on gastric acid secretion in the rat.

The comparison between DL-alpha-(hydrazino)-beta-4(5)imidazolyl-propionic acid (alpha-HH) and DL-gamma-N(1,2,3,4-tetrahydroisoquinolyl)-alpha-hydrazino-butyric acid (AIS 48), a new inhibitor of histidine-decarboxylase shows that both compounds inhibit enzyme activity in vitro and lower gastric histamine content and acid secretion in vivo. The potency of AIS 48 is of the same order as that of alpha-HH while its toxicity is lower. Although AIS 48 is not a selective histidine-decarboxylase inhibitor, it does not affect tissue cathecholamine levels.

Animals↗
PubMed1976

Metabolic effects of bunaftine, a new antiarrhythmic agent: comparison with quinidine, ajmaline, procainamide, xylocaine and propranolol.

The effects of bunaftine (Meregon), quinidine, ajmaline, procainamide, xylocaine and propranolol have been investigated on glycolysis and oxygen consumption of rabbit heart and on the metabolic rate of trained rats. Quinidine, bunaftine and ajmaline stimulated glycolysis, procainamide was inactive while xylocaine and propranolol inhibited it. Myocardial oxygen consumption was reduced by quinidine and bunaftine only at high concentrations. However quinidine at 1-10(5) g/ml showed stimulating effect. Ajmaline and procainamide were inactive; xylocaine had a weak stimulating effect at 1-10(-6), propranolol had a stimulating effect at 3-10(-5) and 1-10(6) while it had an inhibiting effect at 1-10(-4) and 5-10(-3). With the exception of xylocaine and propranolol, which inhibited metabolic rate of trained animals, all the other drugs were inactive. In view of these findings, the mechanism of action of anti-arrhythmic drugs is discussed and it is suggested that the metabolic changes they induce are to be considered as secondary or toxic effects, the main site of action being the myocardial cell membrane.

Ajmaline↗