PubMed Health⌕ Search

Biomedical subjects

G Ronsisvalle

Publications and source records attributed to G Ronsisvalle.

At least 19 recordsLinked to original sources
PubMed2005

The in vitro effect of a lyophilized extract of wine obtained from Jacquez grapes on human chondrocytes.

The present work was aimed at evaluating the in vitro effects of a lyophilized extract of wine (JW-E) obtained from Jacquez grapes (Vitis aestivalis-cinereaxVitis vinifera grapes) on the production of key molecules released in inflammatory disease utilising interleukin-1beta (IL-1beta) activated chondrocytes. The extract contains large amounts of phenolic components, in particular some flavonoids (flavan-3-ols, also known as catechins) and proanthocyanidins, as hydroxycinnamic acids and anthocyanins, that possess several biological features such as antiinflammatory and antioxidant effects and a "radical scavenger" activity too. In this study, we assayed the effect of JW-E on the production of key molecules released during chronic inflammatory events as nitric oxide (NO), prostaglandins E(2) (PGE(2)) and reactive oxygen species (ROS) in human chondrocytes culture, stimulated with proinflammatory cytokine interleukin-1beta. The JW-E proved to possess good ability against the harmfull effects of IL-1beta. Our data showed the protective effects of JW-E in cartilage alteration, that appears greater than that elicited by indomethacin, a not steroidal antiinflammatory drug (NSAID), commonly employed in joint diseases.

Cartilage, Articular↗
PubMed2005

Protective effect of Capparis spinosa on chondrocytes.

The aim of the present study was to evaluate the in vitro chondroprotective effects of the lyophilised methanolic extract from flowering buds of Capparis Spinosa L (LECS). This plant, common to the Mediterranean basin, has been used by the traditional medicine for its diuretic and antihypertensive effects and also in certain pathological conditions related to uncontrolled lipid peroxidation. The extract contains many constituents, in particular some flavonoids (kaempferol and quercetin derivatives) and hydrocinammic acids with several known biological effects such as the anti-inflammatory and the antioxidant ones. In this study, we assayed the effect of LECS on human chondrocytes cultures stimulated by proinflammatory cytokine interleukin-1beta (IL-1beta) and we determined the production of key molecules released during chronic inflammatory events (nitric oxide, glycosaminoglycans, prostaglandins and reactive oxygen species). We observed that LECS was able to counteract the harmful effects induced by IL-1beta. This protection appeared to be greater than that elicited by indomethacin, which is usually employed in joint diseases. Since LECS possess a chondroprotective effect, it might be used in the management of cartilage damage during the inflammatory processes.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

Protective effects of benzisothiazolylamidines on IL-1 beta induced alterations in human articular chondrocyte metabolism.

The in vitro effects on human articular chondrocytes were evaluated for a series of N-benzo[d]isothiazol-3-yl-amidines, bearing as pharmacophoric moiety the nonacidic isosteric nitrogen analogue of the carboxylic group. The aim was to verify their effectiveness in articular diseases, such as arthritis. Human chondrocytes were treated with IL-1beta in the presence of a series of N-benzo[d]isothiazol-3-yl-amidines at a concentration of 100 microg/mL. After 120 h, the amount of glycosaminoglycans (GAGs), the production of nitric oxide (NO) and the inhibition of metalloproteinases (MMP-3) and prostaglandin (PGE2) were measured. Nitrite production induced by inflammatory IL-1beta on cultured chondrocytes was inhibited by the N-benzo[d]isothiazol-3-yl-amidines tested, in particular by N-benzo[d]isothiazol-3-yl-benzamidine, which was the most active. Concerning the effects on GAGs, all the tested benzisothiazolylamidines, and in particular N-benzo[d]isothiazol-3-yl-acetamidine, prevented the depletion of proteoglycan induced by IL-1beta. Inhibitory effects of the tested compounds on MMP-3 activity and on PGE2 production were also observed.

Amidines↗
PubMed2003

Synthesis and anti-measles virus activity of new isoquinolin-4-one derivatives.

Despite intense efforts to increase vaccine coverage, measles virus (MV) still causes significant morbidity and mortality in the world sometimes as a results of severe, chronic and lethal diseases. In an effort to develop therapies to supplement immunization strategies a number of 1-oxo-2-[[(1E)-phenylmethylene]amino]-1,2-dihydroisoquinoline-4-carboxylic acid derivatives were synthesized and evaluated for anti-measles activity. The substituents on the aromatic ring were chosen in order to evaluate the influence of electron-withdrawing or electron-donating effects on the electronic density of the aromatic moiety. We also evaluated the introduction of a vinyl chain between the exocyclic nitrogen and phenyl moiety. The biological results allow to outline some preliminary considerations on structure-activity relationship.

Antiviral Agents↗
PubMed2003

Different in vitro activity of flurbiprofen and its enantiomers on human articular cartilage.

The 2-arylpropionic acid derivatives or 'profens' are an important group of non-steroidal anti-inflammatory drugs that have been used for the symptomatic treatment of various forms of arthritis. These compounds are chiral and the majority of them are still marketed as racemate although it is known that the (S)- form is the principal effective in the cyclooxygenase inhibition. However, recent findings suggest that certain pharmacological effect of 2-arylpropionic acids cannot be attributed exclusively to the (S)-(+) enantiomer. To obtain further insights into the pharmacological effect of profens, the present study investigated the influence of racemic and pure enantiomers of flurbiprofen on the production of nitric oxide and glycosaminoglycans, key molecules involved in cartilage destruction. The culture of human articular cartilage stimulated by interleukin-1beta (IL-1beta), which plays an important role in the degradation of cartilage, has been established, as a profit experimental model, for reproducing the mechanisms involved in the pathophysiology of arthritic diseases. Our results show that mainly (S)-(+)-flurbiprofen decreases, at therapeutically concentrations, the IL-1beta induced cartilage destruction.

Cartilage, Articular↗
PubMed2002

Determination of undecylenic and sorbic acids in cosmetic preparations by high performance liquid chromatography with electrochemical detection.

A highly sensitive and selective method for the determination of sorbic (SA) and undecylenic acid (UA) in cosmetic formulations by a high performance liquid chromatography method with electrochemical detection (ECD) is described. The pre-column derivatizations of SA and UA and the internal standard (cyclohexanoic acid (cHA)) were carried out using 1-(2,5-dihydroxyphenyl)-2-bromoethanone (2,5-DBE) as an electroactive labeling reagent previously synthesized in our lab. The resulting electroactive esters were separated by isocratic elution of a 5 micrometer Hypersil CN column with acetonitrile-acetate buffer eluent. The compounds were detected by a porous graphite electrode set at an oxidation potential of +0.45 V. The analytical method developed in this study is suitable for quality control assays of complex cosmetic formulations containing sorbic and/or UA.

Chromatography, High Pressure Liquid↗
PubMed2002

Analysis of aliphatic amines in air samples by HPLC with electrochemical detection.

A method was developed for the analysis of primary aliphatic amines by high performance liquid chromatography coupled with electrochemical detector. The electrochemical oxidation of aliphatic amines derivatized with 2,5-dihydroxybenzaldehyde was investigated at porous graphite electrodes. The derivatization reactions were performed off-line, before the chromatographic separation. The compounds were separated on a reversed phase column with a methanol-acetonitrile-phosphate buffer and detected setting at an oxidation potential of +0.5 V. The influence of the mobile phase buffer concentration and pH on the detector response was also studied. The derivatization was shown to be quantitative and the response linear between 50 and 200 ng/ml. The method is sensitive, selective and could be applicable for the assay of volatile amines in the field of environmental toxicology and also for biological monitoring after occupational exposure.

Air↗
PubMed2002

In vitro evaluation of thiazolyl and benzothiazolyl Schiff bases on pig cartilage.

A series of anti-inflammatory agents known as Schiff bases, combining thiazolyl and benzothiazolyl ring and vanillin moieties in the same molecule, was synthesized and evaluated for screening anti-degenerative activity on nasal pig cartilage cultures treated with interleukin 1beta, (IL-1beta). The amount of glycosaminoglycans (GAGs), the production of nitric oxide (NO) and prostaglandin E2 (PGE2), released into the culture medium, were detected. The tested Schiff bases decreased, dose-dependently, the NO and PGE2 production and the GAGs release with respect to samples treated with IL-1beta alone, showing a different behavior correlated to their structure. These results suggest that thiazolyl and benzothiazolyl Schiff bases in general, and particularly the Schiff base with bromine and methoxyl group in position three would protect cartilage matrix from degenerative factors induced by IL-1beta.

Animals↗
PubMed2001

Synthesis and pharmacological evaluation of potent and enantioselective sigma 1, and sigma 2 ligands.

In a previous study we found that substitutions of the (+)-cis-N-normetazocine nucleus of (+)-MPCB with 1-adamantanamine provide the compound (+/-)-10 with high affinity and selectivity for sigma receptors. Starting with this result we have synthesized a new series of eight 1-phenyl-2-cyclopropylmethylamines structurally related to (+/-)-10, and binding affinities, with respect to sigma 1, sigma 2, opioid and dopaminergic D2 receptors, have been reported. All compounds showed a negligible opioid and dopaminergic affinity and high selectivity for sigma receptors. Modifications on the amino moiety and methylcarboxyester group of 10 provide compounds with different sigma 1 and sigma 2 binding affinity and selectivity. Moreover, we have also synthesized the respective enantiomers of componds (+/-)-10 and (+/-)-18 in order to evaluate the enantioselectivity for sigma 1 and sigma 2 receptors. The binding data showed that carboxymethylester on the cyclopropane ring was more critical for enantioselectivity than the hydroxymethylenic group. In fact, the (-)-10 enantiomer showed a preference for sigma 1 whereas (+)-10 showed a preference for sigma 2.

Amino Acid Sequence↗
PubMed2001

Synthesis and binding affinity of cis-(-)- and cis-(+)-N-ethyleneamino-N-nordeoxymetazocine and cis-(-)-N-normetazocine analogues at sigma1, sigma2 and kappa opioid receptors.

The synthesis of cis-(+)- and cis-(-)-N-ethyleneamino-N-nordeoxymetazocine and cis-(-)-N-normetazocine analogues is described and their affinities to sigma1, sigma2 and kappa opioid receptors are evaluated. The cis-(+)-deoxy compounds displayed high sigma/kappa selectivity with nanomolar K(i) values for sigma1 receptors, whereas in the cis-(-)-N-normetazocine series the compound (-)-7b was found to bind with nanomolar affinity to the kappa opioid receptor (K(i)=21.5 nM). Compound (-)-7b showed good selectivity for the kappa opioid receptor in comparison to the sigma1 and sigma2 sites and to the mu and delta opioid receptors. A correlation of the binding affinities between cis-(-)- and cis-(+)-N-deoxynormetazocine derivatives show that both isomers of the deoxy analogs have similar sigma1 and sigma2 binding profiles as the cis-(+)-N-normetazocine derivatives.

Animals↗
PubMed2000

Nonpeptide analogues of dynorphin A(1-8): design, synthesis, and pharmacological evaluation of kappa-selective agonists.

Two novel series of kappa opioid receptor agonist analogues of MPCB-GRRI and MPCB-RRI, hybrid ligands of MPCB ((-)-cis-N-(2-phenyl-2-carbomethoxy)cyclopropylmethyl-N-normetazocine ) and of the C-terminal fragments of dynorphin A(1-8), have been synthesized. The critical functional groups of the peptide fragments of hybrid compounds were maintained, and the binding affinities and selectivities for compounds 1-40 to mu, delta, and kappa opioid receptors were analyzed. Compounds 15 and 16, MPCB-Gly-Leu-NH-(CH(2))(n)()-NH-C(=NH)-C(4)H(9) (n = 5, 6), displayed high affinity and selectivity for kappa opioid receptors (K(i)(kappa) = 6.7 and 5.3 nM, K(i)(mu)/K(i)(kappa) = 375 and 408, and K(i)(delta)/K(i)(kappa) = 408 and 424, respectively). Since kappa agonists may also cause psychotomimetic effects by interaction with sigma sites, binding assays to sigma(1) sites were performed where compounds 15 and 16 showed negligible affinity (K(i) > 10 000). Compounds 15 and 16 were further characterized in vivo and showed potent antinociceptive activity in mouse abdominal constriction tests (ED(50) = 0.88 and 1.1 mg/kg, respectively), fully prevented by nor-BNI. Thus, these novel analogues open an exciting avenue for the design of peptidomimetics of dynorphin A(1-8).

Analgesics, Opioid↗
PubMed2000

Modeling of kappa-opioid receptor/agonists interactions using pharmacophore-based and docking simulations.

The interaction of the kappa-opioid receptor with arylacetamide and benzomorphan derivatives acting as agonists was modeled through pharmacophore-based and docking calculations. Potentially bioactive conformations of representative ligands (U-50,488 and its benzo-fused analogues 4 and 6 for arylacetamides and MPCB for benzomorphans) were identified by systematic conformational analysis and docked into a 3D model of the kappa-receptor. The obtained complexes, refined by energy-minimization and molecular dynamics, were evaluated for their consistency with structure-activity relationships and site-directed mutagenesis data. The following interactions are hypothesized to govern the ligand-receptor recognition process: (i) a salt bridge between the Asp138 carboxylate and the protonated nitrogen of the bound agonist; (ii) a hydrogen bond donated by the Tyr312 hydroxyl to the carbonyl oxygen of arylacetamides and MPCB; (iii) hydrophobic interactions established by the dichlorophenyl moiety of arylacetamides and the pendant phenyl ring of MPCB with the surrounding side chains of Tyr312, Leu224, Leu295, and Ala298; (iv) a pi-stacking contact between the Tyr312 side chain and the phenyl ring of arylacetamides; (v) a hydrogen bond linking the His291 imidazole ring to the phenolic hydroxy group featured by typical benzomorphans and the arylacetamides 4 and 6.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed2000

Substituted 1-phenyl-2-cyclopropylmethylamines with high affinity and selectivity for sigma sites.

A series of 1-phenyl-2-cyclopropylmethylamines structurally related to (+)- and (-)-MPCB were synthesized and their binding affinities for sigma1, sigma2, opioid and dopamine (D2) receptors were evaluated. Substitution of the cis-N-normetazocine with different aminic moieties provided compounds with high affinity and selectivity for sigma binding sites with respect to opioid and dopamine (D2) receptors. The observed increase in sigma2 affinity as compared to the parent (+)-MPCB, supports the idea that the particular stereochemistry of (+)-cis-N-normetazocine affects sigma1 selectivity but does not affect sigma1 affinity. The (+/-)-cis isomers of methyl 2-[(1-adamantylamino)methyl]-1-phenylcyclopropane-1-carboxyl ate (18) displayed a higher affinity and selectivity for the sigma1 and sigma2 receptor subtypes compared to the (+/-)-trans 19. Interestingly, the enantiomer (-)-cis 18 displayed a preference for sigma1 receptor subtype whereas the (+)-cis 18 did for sigma2. These results prompt us to synthesize compounds with modification of nitrogen and carboxyl groups. The compounds obtained showed high affinities and selectivity for sigma sites. Moreover, modifications of carboxyl groups provided compounds with the highest affinities in the series. In particular, compound 25 with reverse-type ester showed a Ki of 0.6 and 4.05 nM for sigma1 and sigma2 binding sites, respectively.

Animals↗
PubMed1998

(+)-cis-N-ethyleneamino-N-normetazocine derivatives. Novel and selective sigma ligands with antagonist properties.

A series of (+)-cis-N-normetazocine derivatives has been described, and their affinities for sigma1, sigma2, and phencyclidine (PCP) sites and opioid, muscarinic (M2), dopamine (D2), and serotonin (5-HT2) receptors were evaluated. The effect of the N-substitution with a substituted ethylamino spacer was investigated. Compounds 8c-11c displayed high affinities for sigma1 sites and for opioid receptors. Substitution of the second basic nitrogen either with alkyl or cycloalkyl substituents give compounds (1a-6a) with high affinity and selectivity for sigma1 binding sites. Compounds 1a-5a were further characterized in vivo, and their agonist/antagonist activity was evaluated. In mouse, compound 1a and 2a as well as haloperidol suppressed in a dose-related manner the stereotyped behavior induced by (+)-SKF 10,047. Compounds 3a-5a and (+)-pentazocine do not affect the stereotyped behavior induced by ip injection of (+)-SKF 10,047. Therefore, from this series of compounds we identified potent and selective sigma1 ligands which might prove useful to unveil the functional role of sigma1 sites.

Animals↗
PubMed1995

CCB, a novel specific kappa opioid agonist, which discriminates between opioid and sigma 1 recognition sites.

CCB, 6,11-Dimethyl-1,2,3,4,5,6-hexahydro-3-([2'-methoxycarbonyl-2'-(4- chlorophenyl)cyclopropyl]methyl)-2,6-methano-3-benzazocin-8-ol, displays specificity and very high affinity for kappa opioid receptor types (Ki = 0.41 +/- 0.19 nM). In contrast to other kappa opioid agonists, CCB is also selective with respect to sigma 1 sites (Ki = 1,050 +/- 55 nM). CCB displays antinociceptive and sedative effects in the mouse comparable to those of U50,488H and morphine. Naltrexone fully antagonizes these effects. The sedative effects of CCB are blocked in mice pretreated with naltrexone or nor-BNI. CCB and U50,488H produce a superimposable diuresis in rats. Naltrexone and nor-BNI, both are effective in antagonizing the effect. CCB does not produce any stereotyped behavior or ataxia in the behavioral assay in doses up to 40 mg/kg s.c. These findings suggest that CCB might be a useful tool to investigate the physiological role of kappa opioid receptors.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1995

Synthesis and antimicrobial evaluation of 4-phenyl-3-isoquinolinoyl-hydrazones.

2-Methyl-1-oxo-1,2-dihydro-3-carbazoyl-4-phenylisoquinoline 2, 1-methoxy-7 and 1-chloro-3-carbazoyl-4-phenylisoquinoline 12 as well as a series of their 2-hydrazono-derivatives 3 a-i, 8 a-i and 14 a-i were synthesized and evaluated for their antibacterial and antifungal activities, in vitro. Compound 3 h was fairly active against Staphylococcus aureus, Staphylococcus epidermidis and streptococci group B.

Anti-Bacterial Agents↗
PubMed1994

Synthesis and pharmacological evaluation of 3H-pyridazino[4,5-b][1,4]benzothiazin-4(10H)-one derivatives.

The dialkylamino-alkylation of 3H-pyridazino[4,5-b][1,4]benzothiazin-4(10H)-one-5,5-dioxide 5 produced the 3-dialkylaminoalkyl-derivatives 6. To the same compounds we arrived by selective reduction of the corresponding N-oxides 4, derived from the oxidation of the 3-dialkylaminoalkyl-3H-pyridazino[4,5-b][1,4]benzothiazin-4( 10H)-ones 3. Similarly, the oxidation of the 10-dialkylaminoalkyl analogues 8 afforded the corresponding derivatives 9. The synthesized compounds were tested, as hydrochlorides, for their analgesic and anti-inflammatory activities. The results showed that many of these compounds possess a very good analgesic activity, superior to that of phenylbutazone, apparently not related to the position and the peculiarities of the aminoalkylic side-chain. The anti-inflammatory activity was moderate, comparable only for 4 c to that of phenylbutazone. In the most active compounds a very low ulcerogenic potential and a high LD50 have been observed.

Animals↗