Preferential location of lidocaine and etidocaine in lecithin bilayers as determined by EPR, fluorescence and H-2 NMR

We have examined the effect of the uncharged species of lidocaine (LDC) and etidocaine (EDC) on the acyl chain moiety of egg phosphatidylcholine liposomes. Changes in membrane organization caused by both anesthetics were detected through the use of EPR spin labels (5, 7 and 12 doxyl stearic acid methyl ester) or fluorescence probes (4, 6, 10, 16 pyrene-fatty acids). The disturbance caused by the LA was greater when the probes were inserted in more external positions of the acyl chain and decreased towards the hydrophobic core of the membrane. The results indicate a preferential insertion of LDC at the polar interface of the bilayer and in the first half of the acyl chain, for EDC. Additionally, 2 H NMR spectra of multilamellar liposomes composed by acyl chain-perdeutero DMPC and EPC (1:4 mol%) allowed the determination of the segmental order (S-mol) and dynamics (T-1) of the acyl chain region. In accordance to the fluorescence and EPR results, changes in molecular orientation and dynamics are more prominent if the LA preferential location is more superficial, as for LDC while EDC seems to organize the acyl chain region between carbons 2-8, which is indicative of its positioning. We propose that the preferential location of LDC and EDC inside the bilayers creates a ""transient site"", which is related to the anesthetic potency since it could modulate the access of these molecules to their binding site(s) in the voltage-gated sodium channel. (C) 2007 Elsevier B.V. All rights reserved.

Sequestration of prenylated benzoic acid and chromenes by Naupactus bipes (Coleoptera: Curculionidae) feeding on Piper gaudichaudianum (Piperaceae)

The curculionid beetle Naupactus bipes (Germar, 1824) (Coleoptera: Curculionidae: Brachycerinae) has shown feeding preference for leaves of Piper gaudichaudianum, demonstrating an unexpected specificity for an insect considered to be a generalist. The leaves of P. gaudichaudianum contain the prenylated chromenes gaudichaudianic acid (4, major compound) and its methyl ester (5) in addition to a chromene (3) lacking one prenyl residue. In addition to 4, roots contain the chromone methyl ester (1) and methyl taboganate (2, major compound). Feeding on roots, larvae of N. bipes sequester exclusively the root-specific compounds 1 and 2. Adult beetles sequester the leaf-specific chromenes 3 and 4, but were found to also contain compounds 1 and 2 that are absent in leaves. Therefore, it is suggested that 1 and 2 are sequestered by larvae and can be found in the body of adult insects after long-term storage. In addition, 3 and 4, the major compounds in leaves were found to be associated with the eggs.

Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS

in this work, a simple method for the simultaneous determination of cocaine (COC) and five COC metabolites (benzoylecgonine, cocaethylene (CET), anhydroecgonine, anhydroecgonine methyl ester and ecgonine methyl ester) in human urine using CE coupled to MS via electrospray ionization (CE-ESI-MS) was developed and validated. Formic acid at 1 mol/L concentration was used as electrolyte whereas formic acid at 0.05 mol/L concentration in 1:1 methanol:water composed the coaxial sheath liquid at the ESI nozzle. The developed method presented good linearity in the dynamic range from 250 ng/mL to 5000 ng/mL (coefficient of determination greater than 0.98 for all compounds). LODs (signal-to-noise ratio of 3) were 100 ng/mL for COC and CET and 250 ng/mL for the other studied metabolites whereas LOQ`s (signal-to-noise ratio of 10) were 250 ng/mL for COC and CET and 500 ng/mL for all other compounds. Intra-day precision and recovery tests estimated at three different concentration levels (500, 1500 and 5000 ng/mL) provided RSD lower than 10% (except anhydroecgonine, 18% RSD) and recoveries from 83-109% for all analytes. The method was successfully applied to real cases. For the positive urine samples, the presence of COC and its` metabolites was further confirmed by MS/MS experiments.

Preferential location of lidocaine and etidocaine in lecithin bilayers as determined by EPR, fluorescence and H-2 NMR

We have examined the effect of the uncharged species of lidocaine (LDC) and etidocaine (EDC) on the acyl chain moiety of egg phosphatidylcholine liposomes. Changes in membrane organization caused by both anesthetics were detected through the use of EPR spin labels (5, 7 and 12 doxyl stearic acid methyl ester) or fluorescence probes (4, 6, 10, 16 pyrene-fatty acids). The disturbance caused by the LA was greater when the probes were inserted in more external positions of the acyl chain and decreased towards the hydrophobic core of the membrane. The results indicate a preferential insertion of LDC at the polar interface of the bilayer and in the first half of the acyl chain, for EDC. Additionally, 2 H NMR spectra of multilamellar liposomes composed by acyl chain-perdeutero DMPC and EPC (1:4 mol%) allowed the determination of the segmental order (S-mol) and dynamics (T-1) of the acyl chain region. In accordance to the fluorescence and EPR results, changes in molecular orientation and dynamics are more prominent if the LA preferential location is more superficial, as for LDC while EDC seems to organize the acyl chain region between carbons 2-8, which is indicative of its positioning. We propose that the preferential location of LDC and EDC inside the bilayers creates a "transient site", which is related to the anesthetic potency since it could modulate the access of these molecules to their binding site(s) in the voltage-gated sodium channel. (C) 2007 Elsevier B.V. All rights reserved.

Hepatoprotective and anti-inflammatory effects of silibinin on experimental preeclampsia induced by 1-NAME in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Orchidectomy enhances the effects of phenylephrine in rat isolated portal vein

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mechanisms of the Gastric Antiulcerogenic Activity of Anacardium humile St. Hil on Ethanol-Induced Acute Gastric Mucosal Injury in Rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and thermal characterization of dioctadecyldimethylammonium bromide dispersions by spin labels

Dioctadecyldimethylammonium bromide (DODAB) dispersions obtained by simply mixing the amphiphile in water, and by bath-sonication, were investigated by electron spin resonance (ESR) of stearic acids and their methyl ester derivatives, labeled at the 5th and 16th carbons of the acyl chain. The ESR spectra indicate that the non-sonicated dispersions are formed mainly by one population of DODAB vesicles, either in the gel (T < T-m) or in the liquid-crystalline (T > T-m) state. Around T-m there is a co-existence of the two phases, with a thermal hysteresis of about 3.2 degreesC. In sonicated DODAB dispersions, spin labels indicate two different environments even for temperatures far below T-m: one similar to that obtained with non-sonicated samples, a gel phase, and another one in the liquid-crystalline state. The fluid phase domain present below T-m could correspond to either the periphery of bilayer fragments, reported to be present in sonicated DODAB dispersions, or to high curvature vesicles. (C) 2001 Elsevier B.V. Ireland Ltd. All rights reserved.

New antifungal terpenoid glycosides from Alibertia edulis (Rubiaceae)

Phytochemical investigation from the stems of Alibertia edulis led to the isolation and identification of a new iridoid 6 beta-hydroxy-7-epigardoside methyl ester (1) and a new saponin 3 beta-O-[alpha-L-rhamnopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl]-28-O-beta-D-glucopyranoside pomolate (2), along with three known compounds, shanzhiside methyl ester (3), ixoside (4), and 3,4,5-trimethoxyphenyl 1-O-beta-D-apiofuranosyl-(1 -> 6)-O-beta-D-glucopyranoside (5). The structures of 1 and 2 were established on the basis of their spectroscopic data. Iridoid 1 and saponin 2 exhibited moderate inhibitory activities against Candida albicans and C krusei in a dilution assay.

The effect of L-arginine on guinea-pig and rabbit airway smooth muscle function in vitro

We have investigated the effects of L-arginine, D-arginine and L-lysine on airway smooth muscle responsiveness to spasmogens in vitro. Both L-arginine and D-arginine (100 mM) significantly reduced the contractile potency and maximal contractile response to histamine but not to methacholine or potassium chloride in guinea-pig epithelium-denuded isolated trachea. Similarly, the contractile response to histamine was significantly reduced by L-arginine (100 mM) in rabbit epithelium-denuded isolated bronchus. The amino acid L-lysine (100 mM) failed to significantly alter the contractile potency of histamine in guinea-pig isolated trachea (P>0.05). In guinea-pig isolated trachea precontracted with histamine, both L-arginine and D-arginine produced a concentration-dependent relaxation which was not significantly altered by epithelium removal or by the presence of the nitric oxide synthase inhibitor, NG-nitro L-arginine methyl ester (L-NAME; 50 µM). Thus, at very high concentrations, arginine exhibit a non-competitive antagonism of histamine-induced contraction of isolated airway preparations that was independent of the generation of nitric oxide and was not dependent on charge. These observations confirm previous studies of cutaneous permeability responses and of contractile responses of guinea-pig isolated ileal smooth muscle. Taken together, the data suggest that high concentrations of arginine can exert an anti-histamine effect.

Semi-selective culture medium for Curtobacterium flaccumfaciens pv. flaccumfaciens isolation from bean seeds

Curtobacterium wilt has become an important disease of beans in several localities in the country. Its causal agent, Curtobacterium flaccumfacciens pv. flaccumfaciens (Cff), survives and is disseminated through seeds. To date, few studies have been conducted with the objective of developing an effective and low-cost culture medium to isolate this bacterium from bean seeds, for health analysis purposes. Usually, the culture media employed for coryneform bacteria isolation contain specific carbon sources and antimicrobial products not available in the Brazilian market. A culture medium known as MSCFF was developed (peptone - 5 g, meat extract - 3 g, sucrose - 5 g, agar 15 g, skim milk powder* - 5 g. Congo red* - 0.05 g-, chlorothalonil* - 0.01 g, thiophanate methyl* - 0.01 g, nalidixic acid* - 0.01 g, nitrofurantoin* - 0.01 g. oxacillin* 0.001 g, sodium azide* - 0.001 g and distilled water q.s. 1L; *added after autoclaving the basal medium), which has the ability to inhibit growth of a large amount of saprophytic bacteria, but with low supressivity to Cff isolates. The MSCFF medium was highly effective for Cff isolation from naturally infected bean seeds and could be used for routine detection of this bacterium in bean seeds.

Vascular effects of long-term propranolol administration after chronic nitric oxide blockade

Long-term propranolol treatment reduces arterial blood pressure in hypertensive individuals mainly by reducing peripheral vascular resistance, but mechanisms underlying their vasodilatory effect remain poorly investigated. This study aimed to investigate whether long-term propranolol administration ameliorates the impairment of relaxing responses of aorta and mesenteric artery from rats made hypertensive by chronic nitric oxide (NO) deficiency, and underlying mechanisms mediating this phenomenon. Male Wistar rats were treated with N-omega-Nitro-L-arginine methyl ester (L-NAME; 20 mg/rat/day) for four weeks. DL-Propranolol (30 mg/rat/day) was given concomitantly to L-NAME in the drinking water. Treatment with L-NAME markedly increased blood pressure, an effect largely attenuated by DL-propranolol. In phenylephrine-precontracted aortic rings, the reduction of relaxing responses for acetylcholine (0.001-10 mu M) in L-NAME group was not modified by DL-propranolol, whereas in mesenteric rings the impairment of acetylcholine-induced relaxation by L-NAME was significantly attenuated by DL-propranolol. In mesenteric rings precontracted with KCl (80 MM), DL-propranolol failed to attenuate the impairment of acetylcholine-induced relaxation by L-NAME. The contractile responses to extracellular CaCl2 (1-10 mM) were increased in L-NAME group, and co-treatment with DL-propranolol reduced this response in both preparations in most Ca2+ concentrations used. The NO2/NO3 plasma levels and superoxide dismutase (SOD) activity were reduced in L-NAME-treated rats, both of which were significantly prevented by DL-propranolol. In conclusion, propranolol-induced amplification of the relaxation to acetylcholine in mesenteric arteries from L-NAME-treated rats is sensitive to depolarization. Additional mechanisms involving blockade of Ca2+ entry in the vascular smooth muscle and increase in NO bioavailability contributes to beneficial effects of long-term propranolol treatment. (C) 2007 Elsevier B.V. All rights reserved.

X-ray powder diffraction analysis of a silver(I)-aspartame complex

Synchrotron X-ray powder diffraction (XRPD) data were collected for the silver(I)-aspartame complex [Ag(C14H17N2O5)]center dot 1/2 H2O. The complex was obtained from a stoichiometric mixture of aspartame (3-amino-N-(alpha-carboxyphenethyl)-succinamic acid N-methyl ester, C14H18N2O5), Na2CO3, and AgNO3. Indexing using Crysfire and Chekcell proposed an orthorhombic unit cell with space group P222(1). The lattice parameters are a = 12.4750(1) angstrom, b = 21.60614(14) angstrom, and c = 4.88888(9) angstrom. (C) 2006 International Centre for Diffraction Data.

Similar anxiolytic-like effects following intra-amygdala infusions of benzodiazepine receptor agonist and antagonist: Evidence for the release of an endogenous benzodiazepine inverse agonist in mice exposed to elevated plus-maze test

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Upregulation of gp91(phox) Subunit of NAD(P)H Oxidase Contributes to Erectile Dysfunction Caused by Long-term Nitric Oxide Inhibition in Rats: Reversion by Regular Physical Training

OBJECTIVES To test the hypothesis that glyco protein 91phox (gp91(phox)) subunit of nicotinamide adenine dinucleotide phosphate [NAD(P) H] oxidase is a fundamental target for physical activity to ameliorate erectile dysfunction (ED). Vascular risk factors are reported to contribute to ED. Regular physical exercise prevents cardiovascular diseases by increasing nitric oxide (NO) production and/or decreasing NO inactivation.METHODS Male Wistar rats received the NO synthesis inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) for 4 weeks, after which animals were submitted to a run training program for another 4 weeks. Erectile functions were evaluated by in vitro cavernosal relaxations and intracavernous pressure measurements. Expressions of gp91(phox) subunit and neuronal nitric oxidase synthase in erectile tissue, as well as superoxide dismutase activity and nitrite/nitrate (NO(x)) levels were determined.RESULTS The in vitro acetylcholine-and electrical field stimulation-induced cavernosal relaxations, as well as the increases in intracavernous pressure were markedly reduced in sedentary rats treated with L-NAME. Run training significantly restored the impaired cavernosal relaxations. No alterations in the neuronal nitric oxidase synthase protein expression (and its variant penile neuronal nitric oxidase synthase) were detected. A reduction of NO(x) levels and superoxide dismutase activity was observed in L-NAME-treated animals, which was significantly reversed by physical training. Gene expression of subunit gp91(phox) was enhanced by approximately 2-fold in erectile tissue of L-NAME-treated rats, and that was restored to basal levels by run training.CONCLUSIONS Our study shows that ED seen after long-term L-NAME treatment is associated with gp91(phox) subunit upregulation and decreased NO bioavailability. Exercise training reverses the increased oxidative stress in NO-deficient rats, ameliorating the ED. UROLOGY 75: 961-967, 2010. (C) 2009 Elsevier B.V.