4-Aminopyridine derivatives with antiamnesic activity

Acetylcholine (Ach) enhancement, useful in the treatment of Alzheimer's disease (AD), may be obtained by means of ion channel modulators such as 4-aminopyridine (4-AP). 4-AP is also the central ring of tacrine, the first drug approved for the treatment of AD. The synthesis and pharmacological activity of three 4-AP derivatives, prepared with the aim of improving their antiamnesic activity, is here described. In two of these compounds 4-AP is connected to 4-aminobutyric acid (GABA), whereas in the third it is connected to 2-indolinone, i.e., the skeleton of linopirdine, another Ach enhancing agent. The new compounds showed potent antiamnesic activity in comparison with piracetam.     

Antimicrobial Activity and Phytochemical Constituents of Leaf Extracts of Cassia auriculata

Plants produce a wide variety of phytochemical constituents, which are secondary metabolites and are used either directly or indirectly in the pharmaceutical industry. ‘For centuries, man has effectively used various components of plants or their extracts for the treatment of many diseases, including bacterial infections. In the present study methanol, chloroform and aqueous extracts of Cassia auriculata leaf were subjected for antimicrobial activity by well-diffusion method against six bacterial strains namely Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus mirabilis. The results revealed that the methanol and chloroform extracts exhibited strong inhibitory activity against all the tested organisms (zone of inhibition of 12-20 mm), except Pseudomonas aeruginosa (zone of inhibition 10 mm or nil). The aqueous extracts showed moderate activity by ‘Zone of inhibition ≤12 or nil). The extracts were screened for their phytochemical constituents by standard protocols’ and were shown to contain carbohydrates, proteins, alkaloids, flavonoids, steroids, saponins and tannins. The antibacterial activity of these extracts is possibly linked to the presence of flavonoids, steroid, saponins and/or tannins. Further studies are needed to determine the precise active principles from Cassia auriculata.     

Enhanced histamine-mediated contraction of rabbit penile dorsal artery in diet-induced hypercholesterolemia

The present study was designed to establish whether penile dorsal arteries isolated from rabbits fed a high cholesterol diet show an enhanced contractile and/or impaired vasodilator response to histamine, and to characterize the histamine receptor subtype involved through in vitro isometric techniques. New Zealand White rabbits were fed a normal diet or a 1% cholesterol diet for 16 weeks. Arteries from cholesterol-fed rabbits retained the ability to relax in response to acetylcholine, whereas histamine and noradrenaline induced a greater contraction response compared to that observed in controls. In both groups, histamine-induced contraction was unaffected by the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), its precursor L-arginine or the cyclooxygenase inhibitor indomethacin. Treatment of arterial rings in the control and hypercholesterolemia groups with the H1 receptor antagonist, mepyramine, unmasked a vasodilation response to histamine. This was followed by contraction at higher concentrations showing a leftward displacement of the histamine curve compared to controls. The histamine receptor that induced contraction in preparations from the hypercholesterolemic animals was of the H1 subtype, whereas the receptor involved in histamine-induced relaxation was H2. The affinity of histamine receptor agonists was comparable to their effects in control animals, and receptor antagonists showed the same potency in both groups. Our findings indicate a preserved endothelial function and enhanced contraction in response to histamine in penile dorsal arteries, probably due to a change in the sensitivity of the contractile machinery of smooth muscle but not a mechanism mediated by a receptor.     

Low birth weight, life style of mothers during pregnancy and chlorinated drinking water

Numerous environmental factors such as smoking habits, alcohol intake, economic and social status, and by-product chlorination present in drinking water can determine adverse pregnancy outcomes like a low weight birth, small for gestational age or preterm delivery. In 1998 the Italian Ministry of University and Scientific Technological Research (MURST) has financed a multicentric study in order to evaluate the association between exposure to by-products chlorination in drinking water during pregnancy and adverse pregnancy outcomes at birth such as preterm delivery and low birth weight. We describe the socio demographics characteristics, personal habits and the health status during pregnancy and exposure to the VOX of 171 women recruited from the Research Unit of Rome and L'Aquila. A case control study with incident cases was performed. Exposure to Chlorination By Products (CBP) and confounding factors for studied outcomes, were assessed by a validated questionnaire. At the same time, collection and analysis of 124 tap water samples were carried out directly at women's home. No association was found between CBPs level and low birth weight or preterm delivery. We found an excess risk statistically significantly between preterm delivery and hypertension (OR = 5.06; IC 95% = 1.70-15.44) an excess risk statistically significantly between low birth weight and smokers (OR = 3.43, IC 95% = 1.15-10.26). The CBPs levels were rather low (range cases = 0.09-6.28 microg/L; range controls = 0.01-6.44 microg/L). The results confirm the literature data and the validity of the epidemiological method adopted. The low CBPs levels, under the Law level, are probably imputable to the good quality of sorgive waters. Considering the CBPs level temporal variability in chlorinated waters, is to be hoped a careful and continues surveillance of the CBPs spike levels for better exposure assessment.     

Ca2+-activated K+ (KCa) channels are involved in the relaxations elicited by sildenafil in penile resistance arteries

The aim of the present study was to evaluate the role of K+ channels in the vasorelaxant effect of the phosphodiesterase 5 inhibitor, sildenafil, in isolated horse penile resistance arteries mounted in microvascular myographs. In phenylephrine-precontracted arteries, sildenafil elicited potent relaxations which were markedly reduced by raising extracellular K+, by the non-selective blocker of Ca2+-activated K+ channels (KCa), tetraethylammonium and by the blocker of large- and intermediate-conductance KCa channels, charybdotoxin. Sildenafil relaxant responses were also reduced by the selective inhibitor of large conductance KCa (BK(Ca)) channels iberiotoxin, but not by the blocker of small conductance KCa channels apamin. The inhibitor of the cGMP-dependent protein kinase (PKG), Rp-8-Br-PET-cGMPS, reduced the relaxations elicited by sildenafil but combined treatment with iberiotoxin and Rp-8-Br-PET-cGMPS did not further inhibit these relaxations, compared to the effect of either blocker alone. Iberiotoxin also shifted to the right the relaxations elicited by both the NO donor, S-nitrosoacetyl-D,L-penicillamine (SNAP) and the adenylate cyclase activator forskolin; treatment with both iberiotoxin and Rp-8-Br-PET-cGMPS did cause an additional inhibition. The present results demonstrate that the relaxant effect of sildenafil and NO in penile resistance arteries is due in part to activation of BK(Ca) channels through a PKG-dependent mechanism.     

Oocyte cryopreservation: oocyte assessment and strategies for improving survival

Despite significant progress in cryopreservation of mammalian oocytes and embryos, many ofthe molecular and biochemical events that underlie this technology are poorly understood. In recent years, researchers have focused on obtaining viable oocytes that are developmentally competent. Even under the most favourable conditions, experimental approaches have achieved only limited success compared with fresh oocytes used in routine in vitro embryo production. Chilling injuries and toxic effects of the cryoprotectants are the major adverse consequences following cryoprocedures. To overcome these problems, different strategies have been developed for improving cryopreservation results. These strategies include reducing container volumes, increasing the thermal gradient, changing the cell surface/volume ratio, enhancing cryotolerance by supplementation with various additives or modifying the lipid composition of the oocyte membrane. In order to develop new strategies for reducing the various forms of stress associated with oocyte cryopreservation, it is fundamental to gain a better understanding of the major changes responsible for poor post-thaw survival. With this knowledge, we hope that oocyte cryostorage will become a fully reliable reproductive technique in the near future.     

Prophylaxis with GM-CSF mouthwashes does not reduce frequency and duration of severe oral mucositis in patients with solid tumors undergoing high-dose chemotherapy with autologous peripheral blood stem cell transplantation rescue: a double blind, randomized, placebo-controlled study.

BACKGROUND: The aim of this study was to evaluate the effectiveness of granulocyte-macrophage colony-stimulating factor (GM-CSF) mouthwashes in the prevention of severe mucositis induced by high doses of chemotherapy. PATIENTS AND METHODS: Ninety consecutive patients affected by solid tumors and undergoing high-dose chemotherapy with autologous peripheral blood stem cell transplantation rescue were randomized to receive placebo versus GM-CSF mouthwash 150 micro g/day. Patients were stratified on the basis of the conditioning treatment and the consequent different risk of severe oral mucositis. Treatment was administered from the day after the end of chemotherapy until the resolution of stomatitis and/or neutrophil recovery. RESULTS: The statistical analyses were intention-to-treat and involved all patients who entered the study. The severity of stomatitis was evaluated daily by the physicians according to National Cancer Institute Common Toxicity Criteria. Both study and control groups were compared with respect to the frequency [30% versus 36%, chi(2) exact test, not significant (NS)] and mean duration (4.8 +/- 4.7 versus 4.4 +/- 2.7 days, t-test, NS) of severe stomatitis (grade > or =3). Oral pain was evaluated daily by patients themselves by means of a 10 cm analog visual scale: the mean (+/- standard error of the mean) maximum mucositis scores were 4.8 +/- 3.5 versus 4.2 +/- 3.5 cm (t-test, NS). Furthermore, 15/46 patients in the study group (33%) and 19/44 patients in the control group experienced pain requiring opioids (chi(2) exact test, NS). CONCLUSION: We did not find any evidence to indicate that prophylaxis with GM-CSF mouthwash can help to reduce the severity of mucositis in the setting of the patients we studied.     

Evaluation of resection margins after breast conservative surgery with monoclonal antibodies

An immunocytochemical method for the detection of cancer cells, in the cell suspension obtained by scraping the surface of the surgical resection margins is described and its sensitivity compared to the conventional histology performed on random biopsies from the same margins. The reactivity of the cells with a pool of monoclonal antibodies (Mab) directed against epithelial markers indicated that in 80% of the 42 cases tested, the scraping method was adequate for the gathering of cells from the margins. The analysis of the samples using B72.3 Mab specific for tumor cells revealed that, among B72.3-positive tumor cases, 31% of breast margins contained tumor cells, whereas only 12% were histologically positive. Our results indicate that the immunocytological methodology is therefore more sensitive and should be used alongside histological examination to detect the tumor contamination in the surgical resection margins.