Biomedical subjects

A Capasso

Publications and source records attributed to A Capasso.

At least 19 recordsLinked to original sources

PubMed2006

A novel keratinase from Clostridium sporogenes bv. pennavorans bv. nov., a thermotolerant organism isolated from solfataric muds.

A bacterium which can grow on chicken feathers and which exhibits keratinolytic activity was isolated from solfataric muds. It was classified as belonging to the genus Clostridium and closely related to C. sporogenes. Based on its unique capability to degrade chicken feathers, it was designated as Clostridium sporogenes bv. pennavorans bv. nov. The keratinase purified from the culture supernatant is a monomer of 28.7kDa molecular mass. The enzyme is relatively thermostable and is active over a broad range of temperature and pH. Specific enzymatic assays demonstrate that keratinase can act on a large variety of soluble and insoluble protein substrates.

Anaerobiosis↗

PubMed2006

Safety of ethanolic kava extract: Results of a study of chronic toxicity in rats.

BACKGROUND: Recently, potential liver toxicity was discussed with the intake of kava extract preparations (Piper methysticum) as anxiolytic drugs. The aim of this study was to test chronic toxicity in rats by oral application of an ethanolic kava full extract. METHODS: Wistar rats of both sexes were fed 7.3 or 73 mg/kg body weight of ethanolic kava extract for 3 and 6 months. The animals were examined for changes in body weight, hematological and liver parameters, and macroscopical and microscopical histological changes in the major organs. RESULTS: No signs of toxicity could be found. CONCLUSIONS: The results are in accordance with the medical experience regarding the use of kava preparations and the long tradition of kava drinking in the South Pacific island states. Specifically, the results do not back the suspicion of potential liver toxicity.

Animals↗

PubMed2006

The effect of isoquinoline alkaloids on opiate withdrawal.

Our interest has been centered on isoquinoline alkaloids obtained from Argemone mexicana (Papaveraceae), Aristolochia constricta (Aristolochiaceae) and the opium alkaloid, papaverine. In this respect, the effect of these isoquinoline alkaloids was investigated on contractions induced by naloxone of isolated guinea pig ileum acutely exposed to morphine in vitro. The activity of these alkaloids was compared to the control compound, papaverine. Furthermore, the effect of these isoquinoline alkaloids was also determined on naloxone-precipitated withdrawal in isolated guinea pig ileum exposed to DAMGO (highly selective mu opioid receptor agonist) and U50-488H (highly selective kappa opioid receptor agonist) to test whether the possible interaction of isoquinoline alkaloids on opioid withdrawal involves mu- and/or kappa-opioid receptors. Isoquinoline alkaloids from A. mexicana (from 5 x 10(-6) to 1 x 10(-4) M), from A. constricta (1 x 10(-5) x 10(-5)-1 x 10(-4) M) as well as papaverine treatment (1 x 10(-7)-5 x 10(-6)-1 x 10(-6) M) before or after the opioid agonists were able of both preventing and reversing the naloxone-induced contraction after exposure to mu (morphine and DAMGO) or kappa (U50-488H) opiate receptor agonists in a concentration-dependent manner. Both acetylcholine response and electrical stimulation were also reduced by isoquinoline alkaloids and papaverine treatment as well as the final opiate withdrawal was still reduced. The results of the present study indicate that isoquinoline alkaloids as well as papaverine were able to produce significant influence on the opiate withdrawal in vitro and these compounds were able to exert their effects both at mu and kappa opioid agonists.

Alkaloids↗

PubMed2005

Pharmacological studies on the sedative and hypnotic effect of Kava kava and Passiflora extracts combination.

Kava kava extract, Passiflora extract and a combination of both extracts, administered to mice, caused a significant decrease of the amphetamine-induced hypermotility and significant prolongation of sleeping phase induced by subcutaneous injection of barbiturates. Due to a synergism of both extracts, simultaneously administered the pharmacologically registered effect in both in vivo experiments was found to be superior over the sum of the single separately administered extracts.

Amphetamines↗

PubMed2003

A novel extracellular subtilisin-like protease from the hyperthermophile Aeropyrum pernix K1: biochemical properties, cloning, and expression.

A novel extracellular serine protease designated Pernisine was purified to homogeneity and characterized from the archaeon Aeropyrum pernix K1. The molecular mass, estimated by SDS-PAGE analysis and by gel filtration chromatography, was about 34 kDa suggesting that the enzyme is monomeric. Pernisine was active in a broad range of pH (5.0-12.0) and temperature (60-120 degrees C) with maximal activity at 90 degrees C and between pH 8.0 and 9.0. In the presence of 1 mM CaCl(2) the activity, as a function of the temperature, reached a maximum at 90 degrees C but at 120 degrees C the enzyme retained almost 80% of its maximal activity. Activity inhibition studies suggest that the enzyme is a serine metalloprotease and biochemical data indicate that Pernisine is a subtilisin-like enzyme. The protease gene, identified from the sequenced genome of A. pernix, was amplified from total genomic DNA by PCR technique to construct the expression plasmid pGEX-Pernisine. The Pernisine, lacking the leader sequence, was expressed in Escherichia coli BL21 strain as a fusion protein with glutathione- S-transferase. The biochemical properties of the recombinant enzyme were found to be similar to those of the native enzyme.

Aeropyrum↗

PubMed2003

Nitric oxide is involved in the expression of neocortical spike-and-wave spindling episodes in DBA/2J mice.

This study investigated the possible role of nitric oxide (NO) in the development of neocortical spike-and-wave spindling episodes (S&W) of DBA/2J mice. The administration of distilled water did not modify either the number or duration of S&W in DBA/2J mice during the whole recording period (240 min). L-N(G)-nitro arginine methyl ester (L-NAME) (3-300 microg/mouse, i.c.v.) dose-dependently reduced the S&W of DBA/2J mice. This effect appeared 30 min after drug administration and lasted for the duration of the recording period (240 min). In addition, L-NAME treatment did not induce significant alterations of stereotyped behaviour such as licking, sniffing, chewing or tremors of the head and body and behavioural excitability, whereas the electroencephalogram desynchronized pattern was also significantly reduced. By contrast D-N(G)-nitro arginine methyl ester at the same doses did not affect S&W of mice. The inhibitory effect of L-NAME on S&W of mice was dose-dependently reversed by L-arginine (L-ARG, 3-300 microg/mouse, i.c.v.) but not by D-arginine. Finally, glyceryl trinitrate on its own (3-300 microg/mouse, i.c.v.) significantly increased the S&W of mice and it was also able to reverse the inhibition on S&W of mice operated by L-NAME. These results provide evidence that NO may play a significant role in the development of brain excitability.

Animals↗

PubMed2003

A new dehydrogenase specific towards aromatic aldehydes from a halophilic bacterium.

A new enzyme showing a dehydrogenase activity towards aromatic aldehydes was isolated, purified and characterized from a halophilic strain isolated from saline environment. The enzyme is a monomer of 54 kDa; it is rather thermostable (optimal temperature: 50 degrees C) showing a broad spectrum of activity in a large pH range with the maximum at pH 9.5. The substrate specificity and the effect of ions were evaluated and compared with analogous described proteins.

Aldehyde Dehydrogenase↗

PubMed2001

Dexamethasone modulates hypotension induced by opioids in anaesthetised rats.

The effect of dexamethasone on hypotension induced by mu-, kappa- and delta-opioid receptor agonists was investigated in pentobarbital-anaesthetised rats. Morphine (nonselective opioid receptor agonist), DAGO (D-Ala2-N-methyl-[Phe4-Gly5-ol]enkephalin; mu-opioid receptor-selective agonist), U50-488H (trans(+/-)-3,4-dichloro-N-methyl-N-(2[1pyrrolidynyl]cyclohexyl)-benzeneacetamide; kappa-opioid receptor-selective agonist) and deltorphin II (delta-opioid receptor-selective agonist), given intravenously, 5 micromol/kg, induced hypotension in rats. This hypotension was characterised by a fall in mean arterial blood pressure in 1-2 min that recovered in 30 min for morphine and U50-488H and in 5 or 20 min for DAGO and deltorphin II, respectively. Dexamethasone per se at a dose of 7.5 micromol/kg, i.v. did not significantly modify the mean arterial blood pressure of animals. Dexamethasone administration 90 min, but not 30 or 60 min, before the opioid agonists injection, prevented the hypotension induced by morphine or U50-488H, but not that induced by DAGO or deltorphin II. Pretreatment with RU-38486 (mifepristone; 7.5 micromol/kg, i.v.), a glucocorticoid receptor antagonist, 15 min before the steroid, prevented dexamethasone inhibition of hypotension induced by morphine and U50-488H. Furthermore, pretreatment with cycloheximide, a protein synthesis inhibitor (3.5 micromol/kg, i.v.), was also able to abolish the effects of dexamethasone on morphine- and U50-488H-induced hypotension. Results of the present study indicate that dexamethasone inhibited kappa-opioid receptor-mediated hypotension in rats, indicating a further important functional interaction between corticosteroids and the opioid system at kappa receptors. The ability of cycloheximide and RU-38486 to block dexamethasone effects indicates that steroid interference with kappa-opioid receptor-mediated hypotension involves a protein synthesis-dependent mechanism via glucocorticoid receptors.

Animals↗

PubMed2001

Purinoreceptors are involved in the control of acute morphine withdrawal.

The effects exerted by P1 and P2 purinoceptor agonists and antagonists on the acute opiate withdrawal induced by morphine were investigated in vitro. Following a 4 min in vitro exposure to morphine, the guinea-pig isolated ileum exhibited a strong contracture after the addition of naloxone. The P1 purinoceptor agonist, adenosine, was able dose-dependently to reduce morphine withdrawal whereas alpha,beta-methylene ATP (APCPP), a P2 purinoceptor agonist, increased morphine withdrawal. Caffeine, a P1 purinoceptor antagonist, was able significantly and in a concentration dependent manner to increase morphine withdrawal whereas quinidine, a P2 receptor antagonist, reduced it. The results of our experiments indicate that both P1 and P2 purinoceptor agonists and antagonists are able to influence opiate withdrawal in vitro, suggesting an important functional interaction between the purinergic system and opioid withdrawal.

Animals↗

PubMed2001

Saponins from the roots of Zygophyllum gaetulum and their effects on electrically-stimulated guinea-pig ileum.

A new ursanolide, 3beta-O-alpha-L-rhamnopyranosyl-(1->2)-O-alpha-L-arabinopyranosyl-(1->2)-beta-D-glucopyranosyl)oxy]-ursan-20beta,28-olide, zygophyloside N (1), and three known quinovic acid glycosides were isolated from the methanolic extract of the roots of Zygophyllum gaetulum. The crude extract, some fractions and 3-O-beta-D-glucopyranosyl quinovic acid 28-beta-D-glucopyranosyl ester, significantly and dose-dependently, are able to reduce the electrically-induced contractions of isolated guinea-pig ileum. The structure of compound (1) was determined, using 1D and 2D NMR techniques.

Animals↗

PubMed2001

Involvement of nuclear factor-kB in the expression of opiate withdrawal.

1. To investigate the role of NF-kB in the expression of opiate withdrawal, the effects of PDTC, an inhibitor of NF-kB activation, was studied on acute opiate withdrawal induced by morphine in vitro. 2. After a 4 min in vitro exposure to morphine, a strong contracture of guinea pig isolated ileum was observed after the addition of naloxone. 3. PDTC (1x10(-8)-5x10(-8)-1x10(-7) M) was able to reduce the naloxone-induced contracture after exposure to the opioid agonist in a concentration-dependent fashion. 4. The results of the present study indicate that NF-kB is involved in the expression of opiate withdrawal thus extending and explaining previous papers performed with dexamethasone and selective arachidonic acid metabolites inhibitors.

Animals↗

PubMed2001

Clonidine-induced antinociception and locomotor hypoactivity are reduced by dexamethasone in mice.

The effects of dexamethasone pretreatment on clonidine-induced antinociception and locomotor hypoactivity were investigated in mice. In the hot-plate and the tail-flick tests, dexamethasone administered intraperitoneally at a dose of 1 mg kg(-1), 30 or 60 min before clonidine, reduced clonidine antinociception in both tests and reduced clonidine-induced locomotor hypoactivity in the activity cage. When administered 15 min before clonidine, dexamethasone had no effect on clonidine antinociception. A higher dexamethasone dose (10 mg kg(-1)) induced the same effects observed at a dose of 1 mg kg(-1) in the hot-plate and the tail-flick tests, but the former dose had a stronger effect on locomotor hypoactivity. Dexamethasone (10 ng/mouse) administered intracerebroventricularly 30 min before clonidine was also able to reduce both clonidine-induced antinociception and locomotor hypoactivity. The protein synthesis inhibitor, cycloheximide, administered intraperitoneally at the dose of 10 mg kg(-1), 2 h before clonidine, was able to prevent dexamethasone effects on clonidine-induced antinociception. The glucocorticoid receptor antagonist RU-38486, administered intracerebroventricularly at the dose of 1 ng/mouse, was also able to block dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity, whereas both cycloheximide and RU-38486 per se did not influence pain sensitivity or locomotor activity. These results suggest that the dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity depend on the stimulating effects that dexamethasone exert, on the protein synthesis via the glucocorticoid receptor in the brain.

Adrenergic alpha-Agonists↗

PubMed2001

Arachidonic acid and its metabolites are involved in the expression of neocortical spike-and-wave spindling episodes in DBA/2J mice.

This work was undertaken to study the effects of dexamethasone, indometacin and mifepristone plus dexamethasone on the neocortical spike-and-wave spindling episodes (S&W) in the electrocorticogram of DBA/2J mice. Our data indicate that both dexamethasone and indometacin (1, 10, 100 microg kg(-1), i.p.) reduced the S&W of DBA/2J mice. This effect appeared 30 min after drug administration and lasted for the duration of the recording period (240 min). Mifepristone, a glucocorticoid receptor antagonist (1, 10, 100 microg kg(-1), i.p.), injected 2 h before dexamethasone, totally blocked the steroid effect. These results indicate that both dexamethasone and indometacin significantly reduce the S&W of DBA/2J mice, suggesting a possible involvement of arachidonic acid and its metabolites in the development of brain excitability.

Animals↗

PubMed2001

Alternative technique for subclavian vein cannulation.

BACKGROUND: Subclavian vein catheterism, a commonly used methodology in ICU, is not devoid of complications, even some serious ones (Pneumothorax 0.5%). METHODS: The authors propose an alternative technique based on the use of an introducer needle bent on its own axis to form an arch with its concavity turned towards the Quincke point. On searching the blood vessel, once the subclavian plane has been reached, the needle advancement towards the jugular fosse happens by following the needle curvature. In this way the operator can keep the needle on a plane parallel to the cutaneous one, and all the complications due to involuntary exceeding of the costal plane are avoided. The response of this new technique in 110 patients (study group) is compared through a retrospective study, to 100 patients with whom the standard technique has been used (control group). RESULTS: The study group has presented a significant reduction both of total complications (p<0.05) and of total failures (p< 0.01). CONCLUSIONS: Such results, although pertinent to a still limited study, testify to an improvement in terms of security and efficacy, with the new alternative technique without an increase in costs.

Adult↗

PubMed2001

Effects of cysteamine on nociception in mice.

AIM: The present study was carried to study the effects of cysteamine on nociception in mice. METHODS: The pain assays were the hot plate and the tail flick test. RESULTS: When cysteamine, a drug well known as a somatostatin depletor, was administered 1 and 4 but not 24 h before the tests (hot plate, tail flick), the nociceptive threshold was elevated when the drug was administered at high doses (50 and 100 mg/kg) while at a lower dose (10 mg/kg), it was able to elevate the nociceptive threshold in the hot plate test only. In the hot plate as well the tail flick test cysteamine effects are reversed by naloxone administration and potentiated by morphine administration, whereas neither somatostatin nor cyclo-(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr[Bzl], a reported somatostatin antagonist, changes cysteamine effects. CONCLUSION: These results suggest that cysteamine effects on the nociceptive threshold in the hot plate and tail flick test may be mediated by cysteamine interference with the opioid system.

Analgesics, Non-Narcotic↗

PubMed2000

Zinc transport and metallothionein secretion in the intestinal human cell line Caco-2.

Caco-2, a human cell line, displays several biochemical and morphological characteristics of differentiated enterocytes. Among these is the ability to transport zinc from the apical to the basal compartment. This process was enhanced following exposure by the apical compartment to increasing concentrations of the metal. High pressure liquid chromatography fractionation of the media obtained from cells labeled with radioactive zinc showed that metallothioneins (MTs), small metal-binding, cysteine-rich proteins), were present in the apical and basal media of controls as well as in cells grown in the presence of high concentrations of zinc. Following exposure to the metal, the levels of Zn-MTs in the apical medium increased, while in the basal compartment the greatest part of zinc appeared in a free form with minor changes in the levels of basal MTs. Metabolic labeling experiments with radioactive cysteine confirmed the apical secretion of MTs. A stable transfectant clone of Caco-2 cells (CL11) was selected for its ability to express constitutively high levels of the mouse metallothionein I protein. This cell line showed an enhanced transport of the metal following exposure to high concentrations of zinc and a constitutive secretion of the mouse metallothionein I protein in the apical compartment. Together, these findings strongly support the hypothesis of a functional role between the biosynthesis and secretion of MTs and the transport of zinc in intestinal cells.

Animals↗

PubMed2000

Constituents of Croton menthodorus and their effects on electrically induced contractions of the guinea-pig isolated ileum.

The present study examines the effects of the extracts [petroleum ether, CHCl(3), CHCl(3)MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Croton menthodorus on the electrically induced contractions of the isolated guinea-pig ileum (ECI). The results of the experiments indicate that CHCl(3)/MeOH (9:1) and MeOH extracts, tested at concentrations of 100, 50 and 25 microg/mL, dose-dependently reduced the guinea-pig ileum contractions, whereas petroleum ether and CHCl(3) extracts did not affect it. Furthermore, the partially purified fractions III-VI from the CHCl(3)/MeOH extract, each tested at concentrations of 100, 50 and 25 microg/mL also inhibited ECI. Finally, pure compound 1 (6 x 10(-6), 3 x 10(-6), 1 x 10(-6) M) isolated and purified from the most active fraction III significantly reduced, in a dose-dependent manner, the electrical contractions of the ileum. Compound 1 was identified by NMR and EI-MS data as the morphinandien-7-one, O-methylflavinantine.

Animals↗

PubMed2000

Flavonol glycosides from Aristeguietia discolor reduce morphine withdrawal in vitro.

The effects of extracts, partially purified fractions and four flavonol glycosides 1-4 from Aristeguietia discolor were investigated on the naloxone-precipitated withdrawal contraction of the acute morphine dependent guinea-pig ileum in vitro. After a 4 min in vitro exposure to morphine a strong contraction of guinea-pig isolated ileum was observed after the addition of naloxone. Both MeOH extract (50, 100 and 200 mg/mL), the partially purified fractions I, L, M and N (50, 100 and 200 mg/mL) and flavonol glycosides 1-4 (1 x 10(-4) 5 x 10(-5) 1 x 10(-5) M), injected 10 min before morphine, were capable of blocking the naloxone-induced contraction after exposure to morphine in a concentration-dependent fashion. The results of the present paper suggest that flavonol glycosides from Aristeguietia discolor may play an important role in the control of morphine withdrawal.

Animals↗