Alessandra Zicari

Synthesis, selective anti-Helicobacter pylori activity, and cytotoxicity of novel N-substituted-2-oxo-2H-1-benzopyran-3-carboxamides

N-substituted-3-carboxamido-coumarin derivatives were prepared and evaluated for selective antibacterial activity against 20 isolates of Helicobacter pylori clinical strains, including five metronidazole resistant ones. Some of them possessed the best activity against H. pylori metronidazole resistant strains with MIC values lower than the drug reference (metronidazole). Furthermore, anti-inflammatory activity through the inhibition of the IL-8 production was investigated.

Oxidative stress in diabetes-induced endothelial dysfunction involvement of nitric oxide and protein kinase C.

Reactive oxygen species (ROS) formation plays a major role in diabetes-induced endothelial dysfunction, though the molecular mechanism(s) involved and the contribution of nitric oxide (NO) are still unclear. This study using bovine retinal endothelial cells was aimed at assessing (i) the role of oxygen-dependent vs. NO-dependent oxidative stress in the endothelial cell permeability alterations induced by the diabetic milieu and (ii) whether protein kinase C (PKC) activation ultimately mediates these changes. Superoxide, lipid peroxide, and PKC activity were higher under high glucose (HG) vs. normal glucose throughout the 30 d period. Nitrite/nitrate and endothelial NO synthase levels increased at 1 d and decreased thereafter. Changes in monolayer permeability to 125I-BSA induced by 1 or 30 d incubation in HG or exposure to advanced glycosylation endproduct were reduced by treatment with antioxidants or PKC inhibitors, whereas NO blockade prevented only the effect of 1 d HG. HG-induced changes were mimicked by a PKC activator, a superoxide generating system, an NO and superoxide donor, or peroxynitrite (attenuated by PKC inhibition), but not a NO donor. The short-term effect of HG depends on a combined oxidative and nitrosative stress with peroxynitrite formation, whereas the long-term effect is related to ROS generation; in both cases, PKC ultimately mediates permeability changes.

Macrophage Migration Inhibitory Factor in Human Pregnancy and Labor

PROBLEM: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in reproduction. Presently there is no information on the possible involvement of MIF in the onset of labor.

Linked Activation of Nitric Oxide Synthase and Cyclooxygenase in Peripheral Monocytes of Asymptomatic Migraine Without Aura Patients

Many reports indicate that nitric oxide (NO) could be involved in migraine without aura (MWA), an extremely diffuse clinical event. Since monocyte may be a relevant source of NO, we analysed monocyte activation in MWA patients, in a period in which they were free of symptoms. NO basal production by MWA peripheral monocytes was significantly higher than in healthy subjects (91.25 ± 8.6 μm/106 cells vs. 22.6 ± 3.2 μm/106 cells). Interestingly, even the release of prostaglandin E2 (PGE2), was higher in MWA patients than in healthy subjects (3137 ± 320 pg/106 cells vs. 1531 ± 220 pg/106 cells). The incubation of monocytes from healthy subjects and MWA patients with N-nitro-l-arginine methyl ester caused a marked decrease of both NO and PGE2 release. We hypothesise that NOS and cyclooxygenase pathways in monocytes are linked and are, in MWA patients, up-regulated, even in a symptoms-free period. NO and PGE2 hyperproduction could therefore be involved in the neurovascular modifications leading to migraine attacks.

Synthesis, anti-Candida activity, and cytotoxicity of new (4-(4-iodophenyl)thiazol-2-yl)hydrazine derivatives.

Novel (4-(4-iodophenyl)-thiazol-2-yl)hydrazine derivatives were assayed for their in vitro anti-Candida activity, compared to topical and systemic antifungal drugs, against twenty-seven clinical isolates. The presence of aliphatic chains or specific heteroaromatic rings on hydrazone moiety at position C2 and a 4-iodophenyl at C4 of the thiazole ring gave a promising inhibitory activity especially against Candida albicans and Candida krusei. The most active compounds have been also evaluated for their cytotoxicity and in association with clotrimazole for anti-Candida activity.

Synthesis and cytotoxicity of novel (thiazol-2-yl)hydrazine derivatives as promising anti-Candida agents.

Thirty-eight new (4-(4-substituted-phenyl/2,4-disubstituted-phenyl)-thiazol-2-yl)hydrazine derivatives were synthesized in good yield and assayed for their in vitro anti-Candida activity, compared to topical and systemic antifungal drugs, against twenty-two clinical isolates of Candida spp. The concurrent presence of aliphatic chains or cycloaliphatic rings at N1-hydrazine and a 4-methyl/4-methoxyphenyl at C4 position of the thiazole nucleus exhibited an interesting anti-Candida inhibitory activity. Moreover, some of the most active compounds showed synergistic antifungal effects and lower cell toxicity when combined with clotrimazole.

Hormonal regulation of cytokine release by human fetal membranes at term gestation: effects of oxytocin, hydrocortisone and progesterone on tumour necrosis factor-α and transforming growth factor-β 1 output

Inflammatory cytokines can play an important role in the biomolecular processes leading to labour by regulating prostaglandin production in intrauterine tissues. In the setting of intrauterine infection, an increased production of these cytokines by placenta, decidua and fetal membranes occurs and is responsible for the onset and maintenance of preterm labour. However, the factors involved in the control of cytokine release by these tissues in normal pregnancy at term are still largely unknown. We investigated the possibility that the synthesis and release of tumour necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) by human fetal membranes at term gestation is regulated by several hormones potentially involved either in the maintenance of pregnancy or in the parturitional process. In the present study, the effects of hydrocortisone, progesterone and oxytocin on TNF-alpha and TGF-beta1 release by explants of fetal membranes at term gestation were evaluated. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to assess the effect of the above hormones on mRNA expression; TNF-alpha and TGF-beta1 release in culture medium was quantitifed by ELISA assays. Results show that both tissue mRNA expression for TNF-alpha and TNF-alpha release in culture medium were significantly increased by oxytocin, but not by hydrocortisone and progesterone. On the contrary, all the hormones tested increased both tissue TGF-beta1 mRNA expression and release in culture medium. These findings suggest that TNF-alpha and TGF-beta1 production by human fetal membranes in uncomplicated pregnancy at term is selectively modulated by oxytocin, hydrocortisone and progesterone.

Increased levels of prostaglandins and nitric oxide in esophageal mucosa of children with reflux esophagitis

BACKGROUND Prostaglandin E2 (PGE2) is said to be both protective and detrimental for esophageal mucosal integrity. Nitric oxide (NO) controls several esophageal neuromuscular functions, including relaxation of the lower esophageal sphincter. The purpose of this study was to verify PGE2 and NO levels in esophageal mucosa of children with reflux esophagitis. METHODS The patients were 10 children, age range 7 to 12 years, affected by reflux esophagitis. The control subjects were 10 children, age range 6 to 11 years, with recurrent abdominal pain. Tissue fragments obtained by esophageal biopsies were placed in a culture medium and processed to obtain a cell suspension. Cells were incubated for 24 hours at 37 degrees C. Thereafter, supernatants were collected and divided into aliquots to determine the amounts of PGE2 and NO metabolites. RESULTS Esophageal cells obtained from reflux esophagitis patients synthesize and release a significantly higher (p < 0.01) amount of PGE2 and NO (PGE2 1.9 +/- 0.56 ng/10(6) cells per 24 hours; NO 124.94 +/- 18.36 microM/10(6) cells per 24 hours) than did the control group (PGE2 0.66 +/- 0.14 ng/10(6) cells per 24 hours; NO 68.03 +/- 12.3 microM/10(6) cells per 24 hours). CONCLUSIONS These results suggest that in esophageal mucosa, PGE2 and NO, in low concentrations, are protective, whereas, at high doses, they can be harmful. Higher amounts of PGE2 and NO in the esophageal mucosa of reflux esophagitis patients suggest that similar noxious stimuli trigger the inducible forms of the respective enzyme.

Anti-Candida activity and cytotoxicity of a large library of new N-substituted-1,3-thiazolidin-4-one derivatives.

On the basis of the recent findings about the biological properties of thiazolidinones and taking into account the encouraging results about the antifungal activity of some (thiazol-2-yl)hydrazines, new N-substituted heterocyclic derivatives were designed combining the thiazolidinone nucleus with the hydrazonic portion. In details, 1,3-thiazolidin-4-ones bearing (cyclo)aliphatic or (hetero)aromatic moieties linked to the N1-hydrazine at C2 were synthesized and classified into three series according to the aromatic or bicyclic rings connected to the lactam nitrogen of the thiazolidinone. These molecules were assayed for their anti-Candida effects in reference to the biological activity of the conventional topic (clotrimazole, miconazole, tioconazole) and systemic drugs (fluconazole, ketoconazole, amphotericin B). Finally, we investigated the selectivity against fungal cells by testing the compounds endowed with the best MICs on Hep2 cells in order to assess their cell toxicity (CC50) and we noticed that two derivatives were less cytotoxic than the reference drug clotrimazole. Moreover, a preliminary molecular modelling approach has been performed against lanosterol 14-α demethylase (CYP51A1) to rationalize the activity of the tested compounds and to specify the target protein or enzyme.

Regulation of phosphodiesterase 5 expression and activity in human pregnant and non-pregnant myometrial cells by human chorionic gonadotropin

Objectives: This study has a twofold aim: 1) to investigate whether protein expression and enzyme activity of phosphodiesterase 4 (PDE5) can be detected in human myometrium and undergo changes in relation to the presence of pregnancy and/or labor; 2) to evaluate whether PDE 5 expression and activity in myometrial cells can be influenced by human chorionic gonadotropin (HCG). Methods: Primary cultures of myometrial cells, obtained from non-pregnant women and from pregnant women at tem, either before or during labor, were carried out in the presence of HCG or dibutyryl-cyclic AMP (ad-cAMP), the non-hydrolizable analogue of cAMP. PDE5 expression in cultures of myometrial cells was detected by immunocytochemistry and western blot. PDE5 activity was detected in cell extracts by enzyme assay. Results: PDE5 is expressed and is functionally active in smooth myscle cells. Treatment of cell cultures with HCG and db-cAMP results in a reduction of PDE5 expression and activity. The effects of HCG and db-cAMP are exerted irrespective of the functional status of the myometrium (n0n-pregnant, pregnant not in labor, pregnant in labor). Conclusions: PDE5 protein is expressed in human non-pregnant and pregnant myometrium. HCG reduces PDE5 expression and enzyme activity in smooth muscle cells, possibly through a pathway involving cAMP