Biomedical subjects

S Manzini

Publications and source records attributed to S Manzini.

At least 19 recordsLinked to original sources

PubMed2007

Heterogeneous effect of leucotriene CysLT1 receptor antagonists on antigen-induced motor and inflammatory responses in guinea-pig airways.

1. The effect of montelukast or MEN91507, selective leucotriene CysLT1 receptor antagonists, on antigen-induced airway inflammation and bronchoconstriction were compared in anaesthetized guinea-pigs. 2. In sensitized animals, ovalbumin (0.3 mg kg(-1), i.v.)-induced microvascular leakage in trachea, intrapulmonary airways, total lung (parenchyma and intrapulmonary airways) and urinary bladder was reduced by MEN91507 (0.01-1 micromol kg(-1), i.v.), whereas montelukast (0.01-1 micromol kg(-1), i.v.) antagonized the effect of the antigen only in the lung and urinary bladder. 3. Ovalbumin (1 mg kg(-1), i.v.)-induced bronchoconstriction was dose dependently antagonized by MEN91507 (10-30 micromol kg(-1), i.v.), whereas the effect of montelukast (0.1-30 micromol kg(-1), i.v.) was marginal (15-30% inhibition). Neither MEN91507 nor montelukast (30 micromol kg(-1), i.v.) affected the bronchoconstrictor response induced by acetylcholine (0.3 micromol kg(-1), i.v.) in sensitized animals. 4. It is concluded that montelukast and MEN91507 display a differential activity against the effect of endogenous leucotrienes, despite the fact that both compounds show a similar antagonist profile against exogenous leucotrienes acting through CysLT1 receptors.

Acetates↗

PubMed2001

A comparative study of cellular and molecular pharmacology of doxorubicin and MEN 10755, a disaccharide analogue.

MEN 10755 is a disaccharide anthracycline endowed with a broader spectrum of antitumour activity than doxorubicin (DOX). To investigate the cellular and molecular basis of its action, cytotoxic activity, drug uptake, subcellular localisation, induction of DNA damage, and apoptosis were assessed in the human A2780 ovarian carcinoma cell line. Experiments with radiolabelled anthracyclines indicated that MEN 10755 exhibited reduced cellular accumulation and a different subcellular distribution (higher cytoplasmic/nuclear ratio) than DOX. In spite of the lower nuclear concentration, MEN 10755 was as potent as DOX in eliciting DNA single- and double-strand breaks, G2/M cell arrest, and apoptosis. Sequencing of drug-induced topoisomerase II cleavage sites showed a common DNA cleavage pattern for MEN 10755 and DOX. Cleavage sites were always characterised by the presence of adenine in -1 position. However, the extent of DNA cleavage stimulation induced by MEN 10755 was greater than that produced by DOX. Reversibility studies showed that MEN 10755-stimulated DNA cleavage sites were more persistent than those induced by DOX, thus suggesting a more stable interaction of the drug in the ternary complex. As a whole, the study indicated that the cellular pharmacokinetics of MEN 10755 substantially differs from that of DOX, showing a lower uptake and a different subcellular disposition. In spite of the apparently unfavourable cellular pharmacokinetics, MEN 10755 was still as potent as DOX in inducing topoisomerase-mediated DNA damage. Although the extent and persistence of protein-associated DNA breaks may contribute to the cytotoxic effects, the drug's efficacy as apoptosis inducer and antitumour agent could not be adequately explained on the basis of DNA damage mediated by the known target (i.e. topoisomerase II), thus supporting additional cellular effects that may be relevant in cellular response.

Antineoplastic Agents↗

PubMed2001

Cardioprotective effects of zofenopril, a new angiotensin-converting enzyme inhibitor, on doxorubicin-induced cardiotoxicity in the rat.

We have studied the effect of zofenopril, a new angiotensin-converting enzyme inhibitor in preventing cardiac injury induced by chronic doxorubicin treatment in rats. Cardiac function was assessed by measuring changes in electrocardiogram (ECG) tracings, haemodynamics and cardiac responses in vivo to isoprenaline, 4 weeks after suspension of doxorubicin treatment, in vehicle-treated rats and in animals receiving zofenopril (15 mg/kg/os/day) alone, doxorubicin (1.5 mg/kg i.v. once a week for 5 weeks) or zofenopril+doxorubicin treatment. Doxorubicin induced a significant lengthening of the QalphaT interval, which was completely prevented by zofenopril treatment. The cardiac positive inotropic effect induced by i.v. isoprenaline was selectively depressed by doxorubicin (no changes in chronotropic responses) and this adverse effect of doxorubicin was also prevented in zofenopril+doxorubicin pretreated rats. Doxorubicin induced a significant increase in relative heart weight, which was likewise prevented in zofenopril+doxorubicin treated rats. In separate experiments, zofenopril did not interfere with the antitumor activity of doxorubicin (inhibition of tumor growth in nude mice xenografted with A2780 human tumor line). In conclusion, the oral administration of zofenopril is able to significantly ameliorate, up to 4 weeks after the end of doxorubicin administration, doxorubicin-induced cardiotoxicity without affecting the antitumor activity of this anthracycline.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Pro- and anti-inflammatory actions of ricinoleic acid: similarities and differences with capsaicin.

We have investigated the pro- and anti-inflammatory effects of ricinoleic acid (RA), the main active principle of castor oil, in an experimental model of blepharitis induced by intradermal injection of carrageenan in the guinea-pig eyelid and its possible capsaicin-like mode of action on acutely dissociated rat dorsal root ganglia (DRG) neurons in vitro. Topical treatment with RA (10-100 mg/guinea-pig) or capsaicin (1-10 mg/guinea-pig) caused eyelid reddening and oedema. At lower doses (0.3-3 mg/guinea-pig and 0.009-0.09 mg/guinea-pig for RA and capsaicin, respectively) both drugs significantly potentiated the eyelid oedema induced by carrageenan. The tachykinin NK1 receptor antagonist FK 888 (0.59 mg/kg s.c.) abolished the potentiation of carrageenan-induced eyelid oedema induced by either RA or capsaicin. The neutral endopeptidase inhibitor, thiorphan (1.3 mg/kg i.v.) significantly enhanced the potentiation of carrageenan-induced eyelid oedema produced by RA. This potentiating effect was abolished by FK 888. Repeated (8 days) topical application of RA (0.9 mg/guinea-pig) or capsaicin (0.09 mg/guinea-pig) inhibited the carrageenan-induced eyelid oedema. This anti-inflammatory effect was accompanied by a reduction (75%-80% of SP and 46%-51% of NKA) in tachykinin content of the eyelids, as determined by radioimmunoassay. In dissociated rat DRG neurons, RA (0.1 mM for 5 min) significantly inhibited the inward currents induced by application of capsaicin (1 microM) and/or low pH (5.8), without inducing any currents by itself or changing voltage-dependent currents. Moreover, after 24-h incubation, RA (0.1 mM) significantly decreased the capsaicin (1 microM)-induced calcitonin gene-related peptide (CGRP) release from rat DRG neurons, whereas acute drug superfusion did not evoke CGRP release by itself. Summarizing, RA possesses capsaicin-like dual pro-inflammatory and anti-inflammatory properties which are observed upon acute and repeated application, respectively. However, unlike capsaicin, RA does not induce inward current in DRG neurons and it is devoid of algesic properties in vivo.

Animals↗

PubMed2001

Tissue distribution, antitumour activity and in vivo apoptosis induction by MEN10755 in nude mice.

MEN10755 is a disaccharide analogue of doxorubicin (DXR) endowed with a broader spectrum of activity compared with DXR in a panel of human tumour xenografts. In an attempt to investigate the pharmacological basis of the improvement of therapeutic efficacy of the analogue, a comparative pharmacokinetic (tissue and tumour distribution) and pharmacodynamic (antitumoral activity and ability to induce apoptosis) study of MEN10755 and DXR was performed in athymic nude mice bearing a human ovarian carcinoma xenograft (A2780). Drug level was quantified by high performance liquid chromatography (HPLC) with fluorimetric detection after a single intravenous (i.v.) injection of 7 mg/kg of MEN10755 or DXR. The results indicated a reduced accumulation of MEN10755 compared with DXR in all tissues investigated (tumour, heart, kidney and liver). The reduction was more marked in normal than tumour tissues. Moreover, in spite of the reduced drug uptake by tumour tissues, the new disaccharide anthracycline given in its optimal regimen showed an enhanced antitumour efficacy, compared with DXR. The drug effects on tumour growth paralleled a marked activation of apoptosis. In conclusion, the pattern of tissue distribution and the pharmacokinetic behaviour were consistent with a better tolerability of the novel analogue which allowed a higher cumulative dose to be delivered. The superior therapeutic efficacy of the analogue over DXR, in spite of a reduced tumour accumulation, supports an increased tumour selectivity.

Animals↗

PubMed2001

Effect of the long-acting tachykinin NK(1) receptor antagonist MEN 11467 on tracheal mucus secretion in allergic ferrets.

1. We investigated the effect of MEN 11467 ((1R,2S)-2-N[1(H)indol-3-yl-carbonyl]-1-N-[N(alpha)(p-tolylacetyl)-N(alpha)(methyl)-D-3-(2-naphthyl)alanyl]diaminocyclohexane) on tachykinin-induced mucus secretion in ferret trachea in vitro and determined its effect on secretion by tracheae from allergic ferrets in response to allergen challenge. 2. Repeated administration of [Sar(9),Met(O(2))(11)]-substance P ([Sar(9)]SP, 1 microM) maintained mucus output above control values for at least 1.75 h. MEN 11467 inhibited secretion in a concentration-dependent manner with maximal inhibition at 10 microM and an approximate IC(50) of 0.3 microM. Inhibition by MEN 11467 (0.1--10 microM) was maintained, to varying degree, for at least 1.75 h after washout in the continued presence of [Sar(9)]SP. 3. In electrically stimulated tracheae, tachykininergic neural secretion was virtually abolished by 1 microM MEN 11467. 4. In tracheae from ovalbumin-sensitised animals, repeated administration of ovalbumin maintained mucus output above controls for 1.5 h. MEN 11467 inhibited ovalbumin-induced secretion in a concentration-dependent manner, with complete inhibition at 1 microM. Inhibition by MEN 11467 (1 and 10 microM) was maintained, to varying degree, after drug washout for the 1.5 h of ovalbumin stimulation. 5. MEN 11467 1 microM did not affect secretion induced by either acetylcholine or histamine, whereas 10 microM MEN 11467 did inhibit agonist-induced secretion. 6. We conclude that, in ferret trachea in vitro, MEN 11467 at concentrations of 0.1--1 microM is a long acting and selective inhibitor of tachykininergic-induced mucus secretion, and may have therapeutic potential for bronchial hypersecretion associated with allergic conditions, for example in asthma.

Acetylcholine↗

PubMed2001

Impairment of myocardial contractility by anticancer anthracyclines: role of secondary alcohol metabolites and evidence of reduced toxicity by a novel disaccharide analogue.

1. The anticancer anthracycline doxorubicin (DOX) causes cardiotoxicity. Enzymatic reduction of a side chain carbonyl group converts DOX to a secondary alcohol metabolite that has been implicated in cardiotoxicity. We therefore monitored negative inotropism, assessed as inhibition of post-rest contractions, in rat right ventricle strips exposed to DOX or to analogues forming fewer amounts of their alcohol metabolites (epirubicin, EPI, and the novel disaccharide anthracycline MEN 10755). 2. Thirty microM EPI exhibited higher uptake than equimolar DOX, but formed comparable amounts of alcohol metabolite due to its resistance to carbonyl reduction. MEN 10755 exhibited also an impaired uptake, and consequently formed the lowest levels of alcohol metabolite. Accordingly, DOX and EPI inhibited post-rest contractions by approximately 40-50%, whereas MEN 10755 inhibited by approximately 6%. 3. One hundred microM EPI exhibited the same uptake as equimolar DOX, but formed approximately 50% less alcohol metabolite. One hundred microM MEN 10755 still exhibited the lowest uptake, forming approximately 60% less alcohol metabolite than EPI. Under these conditions DOX inhibited post-rest contractions by 88%. EPI and MEN 10755 were approximately 18% (P<0.05) or approximately 80% (P<0.001) less inhibitory than DOX, respectively. 4. The negative inotropism of 30-100 microM DOX, EPI, or MEN 10755 correlated with cellular levels of both alcohol metabolites (r=0.88, P<0.0001) and carbonyl anthracyclines (r=0.79, P<0.0001). Nonetheless, multiple comparisons showed that alcohol metabolites were approximately 20-40 times more effective than carbonyl anthracyclines in inhibiting contractility. The negative inotropism of MEN 10755 was therefore increased by chemical procedures, like side chain valeryl esterification, that facilitated its uptake and conversion to alcohol metabolite but not its retention in a carbonyl form. 5. These results demonstrate that secondary alcohol metabolites are important mediators of cardiotoxicity. A combination of reduced uptake and limited conversion to alcohol metabolite formation might therefore render MEN 10755 more cardiac tolerable than DOX and EPI.

Alcohols↗

PubMed2001

Apoptotic events in a human ovarian cancer cell line exposed to anthracyclines.

Cytotoxic drugs commonly used in cancer therapy promote tumor cell death by inducing apoptosis, but the cell death pathway(s) is likely dependent on the mechanism of drug action. In the present study, we investigated the mechanisms of cell death induced by doxorubicin (DXR) and the novel disaccharide anthracycline MEN 10755, in a human ovarian cancer cell line (A2780). Exposure to either anthracycline induced the up-regulation of several genes known to promote cell cycle arrest and DNA repair (WAF1/p21, GADD45) or apoptosis (bax, Fas). Although the expression of Fas was increased, an antagonistic anti-Fas antibody ZB4 did not inhibit anthracycline-induced apoptosis, suggesting that the stimulation of the Fas receptor did not play a critical role in the induction of apoptosis in this cell line. We also observed that neither MEN 10755 nor DXR were able to induce apoptosis in A2780 cells deprived of the nucleus but retaining an intact mitochondrial function (cytoplasts) and that apoptosis induced by either anthracycline was inhibited by cycloheximide, indicating that it is an active process requiring new protein synthesis. Both the caspases inhibitors, ZVAD-fmk and DEVD-cho, inhibited at similar extent apoptosis induced by either DXR or MEN 10755, suggesting an involvement of caspase-3 in this response. We conclude that, in a tumor cell line of epithelial origin, the apoptosis following exposure to anthracyclines is an active process requiring protein synthesis and drug interaction with nuclear structures. The pathway was Fas-independent but likely involved bax and caspase-3 as effectors of the cascade culminating in apoptosis.

Annexins↗

PubMed2000

Antinociceptive activity of ricinoleic acid, a capsaicin-like compound devoid of pungent properties.

The antinociceptive effect of ricinoleic acid ([R-(Z)]-12-hydroxy-9-octadecenoic acid) in comparison with capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) has been investigated in several "in vivo" tests. Acute topical application of capsaicin, but not ricinoleic acid, produced by itself an hyperalgesic effect detected as a decrease in paw withdrawal latency in response to a painful (heat) stimulus in mice. Capsaicin, but not ricinoleic acid at any dose tested, showed an irritant effect in the wiping test in guinea pig conjunctiva after local application and in the paw licking test in mice after intradermal injection. Whereas acute application of ricinoleic acid or capsaicin decreased paw withdrawal latency to heat in the presence of a pre-existing inflammation (injection of carrageenan in the mouse paw), the repeated local treatment for 8 days with either compounds markedly increased paw withdrawal latency. In a chronic model of inflammation (complete Freund's adjuvant arthritis in mice), the repeated topical and intradermal treatments with both ricinoleic acid and capsaicin increased paw withdrawal latency to heat, the antinociceptive effect of ricinoleic acid being more persistent than that of capsaicin. Antinociceptive effect of 8 days of treatment with ricinoleic acid and capsaicin was observed in acetic acid-induced writhing in mice, capsaicin-induced foot licking in mice and capsaicin-induced wiping movements in guinea pig conjunctiva. A decrease of substance P tissue levels in the mouse paw was found after repeated treatment with ricinoleic acid. In conclusion, ricinoleic acid seems to be a new antinociceptive agent lacking the pungent and acute hyperalgesic properties of capsaicin.

Administration, Topical↗

PubMed2000

Induction of anti-DNA antibodies in preautoimmune NZBxNZW F1 mice by immunization with a DNA-DNase I complex.

Recent studies suggest that anti-DNA antibodies may arise from the immune response to a complex of DNA and a DNA-binding protein. One of the protein targets frequently recognized by anti-DNA antibodies is the enzyme DNase I. To investigate the possible role of DNase I in the induction of anti-DNA antibodies, we immunized preautoimmune NZBxNZW F1 mice with a complex of DNA and DNase I emulsified in complete Freund's adjuvant. Control mice received DNA or DNase in adjuvant. IgG anti-dsDNA antibodies were induced in 50% of the mice immunized with DNA-DNase, in 25% of the mice immunized with DNase and in 6% of the mice immunized with DNA. However, immunized mice that produced anti-DNA antibodies did not develop renal disease. These data show that a DNA-binding protein like DNase may act as carrier in the immune response that leads to anti-DNA antibodies production in an autoimmune strain, but the induced anti-dsDNA antibodies have a low pathogenic potential.

Animals↗

PubMed2000

Anthracycline metabolism and toxicity in human myocardium: comparisons between doxorubicin, epirubicin, and a novel disaccharide analogue with a reduced level of formation and [4Fe-4S] reactivity of its secondary alcohol metabolite.

Secondary alcohol metabolites have been proposed to mediate chronic cardiotoxicity induced by doxorubicin (DOX) and other anticancer anthracyclines. In this study, NADPH-supplemented human cardiac cytosol was found to reduce the carbonyl group in the side chain of the tetracyclic ring of DOX, producing the secondary alcohol metabolite doxorubicinol (DOXol). A decrease in the level of alcohol metabolite formation was observed by replacing DOX with epirubicin (EPI), a less cardiotoxic analogue characterized by an axial-to-equatorial epimerization of the hydroxyl group at C-4 in the amino sugar bound to the tetracyclic ring (daunosamine). A similar decrease was observed by replacing DOX with MEN 10755, a novel anthracycline with preclinical evidence of reduced cardiotoxicity. MEN 10755 is characterized by the lack of a methoxy group at C-4 in the tetracyclic ring and by intercalation of 2, 6-dideoxy-L-fucose between daunosamine and the aglycone. Multiple comparisons with methoxy- or 4-demethoxyaglycones, and a number of mono- or disaccharide 4-demethoxyanthracyclines, showed that both the lack of the methoxy group and the presence of a disaccharide moiety limited alcohol metabolite formation by MEN 10755. Studies with enzymatically generated or purified anthracycline secondary alcohols also showed that the presence of a disaccharide moiety, but not the lack of a methoxy group, made the metabolite of MEN 10755 less reactive with the [4Fe-4S] cluster of cytoplasmic aconitase, as evidenced by its limited reoxidation to the parent carbonyl anthracycline and by a reduced level of delocalization of Fe(II) from the cluster. Collectively, these studies (i) characterize the different influence of methoxy and sugar substituents on the formation and [4Fe-4S] reactivity of anthracycline secondary alcohols, (ii) lend support to the role of alcohol metabolites in anthracycline-induced cardiotoxicity, as they demonstrate that the less cardiotoxic EPI and MEN 10755 share a reduction in the level of formation of such metabolites, and (iii) suggest that the cardiotoxicity of MEN 10755 might be further decreased by the reduced [4Fe-4S] reactivity of its alcohol metabolite.

Antibiotics, Antineoplastic↗

PubMed2000

Anti-tumour activity of tachykinin NK1 receptor antagonists on human glioma U373 MG xenograft.

Astrocytes harbour functional receptors to many neurotransmitters, including substance P (SP), an undecapeptide belonging to the tachykinin family of peptide transmitters. SP activates malignant glial cells to induce cytokine release and proliferation, both responses being relevant for tumour progression. In tumours developed in nude mice transplanted subcutaneously (s.c.) to U373 MG human glioma cells, the presence of SP was observed at immunohistochemistry. Although the administration of exogenous SP did not significantly affect the size or development of U373 MG xenograft, a role of SP in supporting glioma progression in vivo was highlighted by the tumour growth inhibition induced by highly specific and selective human tachykinin NK1 receptor antagonists (MEN 11467 and MEN 11149). The anti-tumour activity of MEN 11467 was observed both with s.c. or intravenous treatments and was partially reverted by the concomitant administration of exogenous SP. Doxorubicin did not show any activity in controlling U373 MG growth in this in vivo model. A novel therapeutic approach to treat malignant gliomas with tachykinin NK1 receptor antagonists is suggested by these findings.

Animals↗

PubMed2000

Protective effect of the tachykinin NK2 receptor antagonist nepadutant in acute rectocolitis induced by diluted acetic acid in guinea-pigs.

We have evaluated the potential protective activity of nepadutant, a selective tachykinin NK2 receptor antagonist, in a model of acute rectocolitis induced by an enema with 7.5% acetic acid in guinea-pigs. The injury was quantified visually by using a macroscopic injury score, and histologically by using a necrosis score. In addition, changes in myeloperoxidase activity, a marker for neutrophil infiltration, and plasma protein extravasation were evaluated. The injury caused by 7.5% acetic acid was mild, affecting the superficial layers and producing a strong edema of the submucosa. A single administration of nepadutant (0.3-10 mg/kg s.c., 1 h before acetic acid) markedly reduced the macroscopic damage and necrosis score and the increase in plasma protein extravasation induced by 7.5% acetic acid in the early phase of the injury. Single administration of nepadutant (3 mg/kg s.c.) reduced the macroscopic score and myeloperoxidase activity at the top (24 h) of inflammation. Repeated administration (3 mg/kg s.c. three times during 24 h) or co-administration of the tachykinin NK1 receptor antagonist MEN 11467 (3 mg/kg s.c.) did not enhance the antiulcer effect obtained with the single treatment with nepadutant. These data suggest the involvement of tachykinin NK2 receptors in the first phases of inflammation induced by acetic acid.

Acetic Acid↗

PubMed2000

Effect of ricinoleic acid in acute and subchronic experimental models of inflammation.

Observational studies indicate that topical application of ricinoleic acid (RA), the main component of castor oil, exerts remarkable analgesic and anti-inflammatory effects. Pharmacological characterization has shown similarities between the effects of RA and those of capsaicin, suggesting a potential interaction of this drug on sensory neuropeptide-mediated neurogenic inflammation. The aim of this study was to assess RA anti-inflammatory activities in comparison with capsaicin in several models of acute and subchronic inflammation. The acute inflammation was induced by intradermal injection of carrageenan in the mouse or by histamine in the guinea-pig eyelid. In either experiment, the extent of the oedema thickness was measured. Subchronic oedema was induced by complete Freund's adjuvant injection in the ventral right paw of mice. Tissue substance P (SP) was measured in the carrageenan experiments by radioimmunoassay (RIA). It was found that the acute topical application of RA (0.9 mg/mouse) or capsaicin (0.09 mg/mouse) significantly increased the mouse paw oedema induced by carrageenan, while an 8-day repeated topical treatment with the same doses of both compounds resulted in a marked inhibition of carrageenan-induced paw oedema matched by a reduction in SP tissue levels. Similar effects were found against histamine-induced eyelid oedema in guinea-pigs after acute or repeated application of RA or capsaicin. RA and capsaicin given for 1-3 weeks reduced the established oedema induced by Freund's adjuvant, a subchronic model of inflammation, particularly if given by the intradermal route. Either in mouse paw or in guinea-pig eyelid, capsaicin but not RA by itself produced a slight hyperemia and activation of a behavioural response (e.g. scratching of the eyelids). On the basis of the present results, RA may be seen as a new capsaicin-like, non-pungent anti-inflammatory agent suitable for peripheral application.

Acute Disease↗

PubMed2000

Comparison of doxorubicin- and MEN 10755-induced long-term progressive cardiotoxicity in the rat.

The delayed functional cardiotoxic effects of repeated treatment with the new disaccharide anthracycline MEN 10755 and doxorubicin (1.5 mg/kg, i.v., once a week for 5 consecutive weeks) were investigated in the rat. Changes were assessed (2 days and 4 and 13 weeks after the last treatment) in ECG morphology, hemodynamics, in vivo left ventricular contractile responses to beta-adrenergic stimulation, and histopathology of both atria and ventricles. Doxorubicin induced significant and progressive prolongation of the QalphaT interval starting 2 days after suspension of treatment. At 4 and 13 weeks after the last treatment, the ECG showed a further progressive and significant impairment. MEN 10755 induced alterations similar in nature but of lesser severity compared with doxorubicin. In addition, MEN 10755-induced prolongation of the QalphaT interval was not progressive, being similar at 4 and 13 weeks after the last treatment. Although the hemodynamics were only slightly affected by both anthracyclines, a nearly complete ablation of isoprenaline-induced enhancement of ventricular function was observed 4 and 13 weeks after the last treatment with doxorubicin, whereas only mild, if any, reduction was detected in rats receiving MEN 10755. Histopathologic investigations indicated that both anthracyclines produced qualitatively similar alterations in ventricular myocytes. However, only with doxorubicin did these changes show a progression with a further significant worsening at 13 weeks as compared with 4 weeks after the last treatment. In addition, atrial lesions were evident in doxorubicin-treated rats, but not in rats receiving MEN 10755. In conclusion, an equimyelotoxic regimen of MEN 10755 produced, as compared with doxorubicin, lesser ECG alterations, smaller impairment of the ventricular response to adrenergic stimulation, and less severe myocyte lesions. Unlike doxorubicin, the histologic and functional cardiotoxic effects induced by MEN 10755 were not progressive. Further investigations are warranted to define the pharmacodynamic and/or pharmacokinetic mechanism(s) underlying the different cardiotoxic profile exhibited by the two anthracyclines.

Animals↗

PubMed2000

Synthesis and biological activity of the penem antibiotic MEN 10700 and its orally absorbed ester MEN 11505.

The synthesis and biological properties of the new penem antibiotic MEN 10700 (6) and of its selected oral prodrug MEN 11505 (8f) are described. MEN 10700 showed a broad spectrum of activity, with high potency both on Gram-positive and Gram-negative strains. It also exhibited good antibacterial activity toward anaerobes and on strains selected for their resistance to other antibacterial agents (cefotaxime- or ceftazidime-resistant Gram-negative strains, ciprofloxacin-resistant E. coli, extended spectrum beta-lactamase producing and cephalosporinase inducible enterobacteria). MEN 10700 showed a very high stability to enzymatic degradation by renal dehydropeptidase DHP-I. After oral administration in rats of the pivaloyloxymethyl ester prodrug MEN 11505, the relative bioavailability of MEN 10700 was calculated as F=43%.

Administration, Oral↗

PubMed1999

Correlation between binding characteristics and functional antagonism in human glioma cells by tachykinin NK1 receptor antagonists.

Binding characteristics and functional antagonism exerted by two structurally related tachykinin NK1 receptor antagonists, MEN 11467 ((1R,2S)-2N[1(H)indol-3-yl-carbonyl]-1-N-{Nalpha(p-tolylacetyl+ ++)-Nalpha(methyl)-D-3-(2-naphthyl)alanyl}diaminocyclohexane) and FK888 (N2-[(4R)-4-hydroxy-1-(1-methyl-1H-indol-3-yl)carbonyl-L-prolyl]-N-methy l-N-phenylmethyl-L-3-(2-naphthyl)alaninamide), were investigated in the human astrocytoma cell line U373 MG. In radioligand binding studies, conducted with [3H]substance P and intact cells at 37 degrees C, MEN 11467 bound to tachykinin NK1 receptors in an irreversible manner with a Ki value of 1.2+/-0.5 nM while FK888 bound in competitive manner with a Ki value of 4.6+/-2.2 nM. Receptor blockade by both antagonists resulted in a powerful and complete inhibition of functional responses induced by substance P, such as accumulation of the second messenger inositol monophosphate or interleukin-6 release. However, MEN 11467 showed a greater potency for blocking functional responses than FK888 despite their similar affinity for human tachykinin NK1 receptors. Moreover, MEN 11467 was more potent in inhibiting late rather than early phases of substance P-induced inositol monophosphate accumulation and its antagonism was enhanced by drug preincubation and barely affected by removal of unbound drug from the external medium, suggesting that MEN 11467 bound in a tight manner to the receptor. Such behaviour was not observed with the competitive and rapidly reversible antagonist FK888. These data indicate that the small differences in the chemical structure of MEN 11467 and FK888 determine the different binding characteristics at the tachykinin NK1 receptor and which are responsible for the greater potency of MEN 11467 for blocking functional responses. The Ki value obtained in binding studies may be inadequate to reveal the real potency of tachykinin NK1 receptor antagonists.

Binding, Competitive↗

PubMed1999

Effect of MEN 11467, a new tachykinin NK1 receptor antagonist, in acute rectocolitis induced by acetic acid in guinea-pigs.

The aim of this study was to evaluate the effect of MEN 11467 (1R,2S)-2-N[1(H)indol-3-yl-carbonyl]-1-N{N-(p-tolylacetyl)-N-(meth yl)-D-3(2-Naphthyl)alanyl}diaminocyclohexane), a new potent tachykinin NK1 receptor antagonist, in an experimental model of acute rectocolitis induced by an enema with 7.5% acetic acid in guinea-pigs. This effect was compared to that of mesalazine (5-amino-2-hydroxybenzoic acid). The injury was quantified visually by using a macroscopic injury score and histologically by using a necrosis score. In addition, changes in myeloperoxidase activity, a marker for neutrophil infiltration, and plasma protein extravasation were evaluated. The injury caused by 7.5% acetic acid was mild, affecting the superficial layers and producing a strong edema of the submucosa. A single administration of MEN 11467 (0.3-10 mg/kg s.c., I h before acetic acid) reduced the macroscopic damage and necrosis score and the increase in plasma protein extravasation induced by 7.5% acetic acid in the early acute phase of the injury (death at 2.5 h). Mesalazine (100 mg/kg p.o., 1 h before) reduced the macroscopic score but not the plasma protein extravasation. Repeated administration of MEN 11467 (1-3 mg/kg s.c., -1, +6 and +23 h after 7.5% acetic acid) reduced the macroscopic score and myeloperoxidase activity but not the plasma protein extravasation induced in the late phase of acute injury (death at 24 h). At this time mesalazine markedly reduced the macroscopic score, myeloperoxidase activity and plasma protein extravasation induced by 7.5% acetic acid. These results suggest a greater involvement of tachykinin NK1 receptors in the early phase than in the late phase of colonic inflammation in response to chemical injury.

Acetic Acid↗