Enzymatic inhibitory activity and trypanocidal effects of extracts and compounds from Siphoneugena densiflora O. Berg and Vitex polygama Cham.

Hexanic, methanolic, and hydroalcoholic extracts, and 34 isolated compounds from Vitex polygama Cham. (Lamiaceae, formely Verbenaceae) and Siphoneugena densiflora O. Berg (Myrtaceae) were screened for their trypanocidal effects on bloodstream forms of Trypanosoma cruzi and T brucei, as well as for their enzymatic inhibitory activities on glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) and trypanothione reductase (TR) enzymes from T cruzi and adeninephosphoribosyl transferase (APRT) enzyme from Leishmania tarentolae. In general, polar extracts displayed strong effects and some of the tested compounds have shown good results in comparison to positive controls of the bioassays.

A chemometric study on the analgesic activity of cannabinoid compounds using SDA, KNN and SIMCA methods

The supervised pattern recognition methods K-Nearest Neighbors (KNN), stepwise discriminant analysis (SDA), and soft independent modelling of class analogy (SIMCA) were employed in this work with the aim to investigate the relationship between the molecular structure of 27 cannabinoid compounds and their analgesic activity. Previous analyses using two unsupervised pattern recognition methods (PCA-principal component analysis and HCA-hierarchical cluster analysis) were performed and five descriptors were selected as the most relevants for the analgesic activity of the compounds studied: R (3) (charge density on substituent at position C(3)), Q (1) (charge on atom C(1)), A (surface area), log P (logarithm of the partition coefficient) and MR (molecular refractivity). The supervised pattern recognition methods (SDA, KNN, and SIMCA) were employed in order to construct a reliable model that can be able to predict the analgesic activity of new cannabinoid compounds and to validate our previous study. The results obtained using the SDA, KNN, and SIMCA methods agree perfectly with our previous model. Comparing the SDA, KNN, and SIMCA results with the PCA and HCA ones we could notice that all multivariate statistical methods classified the cannabinoid compounds studied in three groups exactly in the same way: active, moderately active, and inactive.

Signal Transduction, Plasma Membrane Calcium Movements, and Pigment Translocation in Freshwater Shrimp Chromatophores

Crustacean color change results from the differential translocation of chromatophore pigments, regulated by neurosecretory peptides like red pigment concentrating hormone (RPCH) that, in the red ovarian chromatophores of the freshwater shrimp Macrobrachium olfersi, triggers pigment aggregation via increased cytosolic cGMP and Ca(2+) of both smooth endoplasmatic reticulum (SER) and extracellular origin. However, Ca(2+) movements during RPCH signaling and the mechanisms that regulate intracellular [Ca(2+)] are enigmatic. We investigate Ca(2+) transporters in the chromatophore plasma membrane and Ca(2+) movements that occur during RPCH signal transduction. Inhibition of the plasma membrane Ca(2+)-ATPase by La(3+) and indirect inhibition of the Na(+)/Ca(2+) exchanger by ouabain induce pigment aggregation, revealing a role for both in Ca(2+) extrusion. Ca(2+) channel blockade by La(3+) or Cd(2+) strongly inhibits slow-phase RPCH-triggered aggregation during which pigments disperse spontaneously. L-type Ca(2+) channel blockade by gabapentin markedly reduces rapid-phase translocation velocity; N- or P/Q-type blockade by omega-conotoxin MVIIC strongly inhibits RPCH-triggered aggregation and reduces velocity, effects revealing RPCH-signaled influx of extracellular Ca(2+). Plasma membrane depolarization, induced by increasing external K(+) from 5 to 50 mM, produces Ca(2+)-dependent pigment aggregation, whereas removal of K(+) from the perfusate causes pigment hyperdispersion, disclosing a clear correlation between membrane depolarization and pigment aggregation; K(+) channel blockade by Ba(2+) also partially inhibits RPCH action. We suggest that, during RPCH signal transduction, Ca(2+) released from the SER, together with K(+) channel closure, causes chromatophore membrane depolarization, leading to the opening of predominantly N- and/or P/Q-type voltage-gated Ca(2+) channels, and a Ca(2+)/cGMP cascade, resulting in pigment aggregation. J. Exp. Zool. 313A:605-617, 2010. (C) 2010 Wiley-Liss, Inc.

Identification of trail pheromone compounds from the labial glands of the stingless bee Geotrigona mombuca

Foragers of several species of stingless bees deposit pheromone spots in the vegetation to guide recruited nestmates to a rich food source. Recent studies have shown that Trigona and Scaptotrigona workers secrete these pheromones from their labial glands. An earlier report stated that species within the genus Geotrigona use citral from their mandibular glands for scent marking. Since convincing experimental proof for this conjecture is lacking, we studied the glandular origin of the trail pheromone of Geotrigona mombuca. In field bioassays, newly recruited bees were diverted by artificial scent trails that branched off from the natural scent trail deposited by their nestmates only when they were baited with extracts from the foragers` labial glands. Compounds extracted from the mandibular glands, however, did not release trail following behavior. This demonstrates that the trail pheromone of G. mombuca is produced in the labial glands, as in Trigona and Scaptotrigona. Furthermore, in chemical analyses citral was identified exclusively in the foragers` mandibular glands, which disproves its supposed role as a trail pheromone. The labial glands contained a series of terpene- and wax type esters, with farnesyl butanoate as major constituent. We, therefore, postulate that the trail pheromone of G. mombuca is composed of a blend of esters.

Calcium Carbonate Particle Growth Depending on Coupling among Adjacent Layers in Hybrid LB/LbL Films

There are practical and academic situations that justify the study of calcium carbonate crystallization and especially of systems that are associated with organic matrices and a confined medium. Despite the fact that many different matrices have been studied, the use of well-behaved, thin organic films may provide new knowledge about this system. In this work, we have studied the growth of calcium carbonate particles on well-defined organic matrices that were formed by layer-by-layer (LbL) polyelectrolyte films deposited on phospholipid Langmuir-Blodgett films (LB). We were able to change the surface electrical charge density of the LB films by changing the proportions of a negatively charged lipid, the sodium salt of dimyristoyl-sn-glycero-phosphatidyl acid (DMPA), and a zwitterionic lipid. dimyristoyl-sn-glycero-phosphatidylethanolamine (DMPE). This affects the subsequent polyelectrolyte LbL film deposition, which also changes the the nature of the bonding (electrostatic interaction or hydrogen bonding). This approach allowed for the formation of calcium carbonate particles of different final shapes, roughnesses, and sizes. The masses of deposited lipids, polyelectrolytes, and calcium cabonate were quantified by the quartz crystal microbalance technique. The structures of obtained particles were analyzed by scanning electron microscopy.

Synthesis and spectral investigation of Al(III) catechin/beta-cyclodextrin and Al(III) quercetin/beta-cyclodextrin inclusion compounds

Al-catechin/beta-cyclodextrin and Al-quercetin/beta-cyclodextrin (beta-CD) inclusion compounds were synthesized and characterized by IR, UV-vis, H-1 and C-13 NMR and TG and DTA analyses. Because quercetin is sparingly soluble in water, the stability constants of the Al-quercetin/beta-CD and Al-catechin/beta-CD compounds were determined by phase solubility studies. The A(L)-type diagrams indicated the formation of 1:1 inclusion compounds and allowed calculation of the stability constants. The thermodynamic parameters were obtained from the dependence of the stability constants on temperature and results indicated that the formation of the inclusion compounds is an enthalpically driven process. The thermal decomposition of the solid Al-quercetin/beta-CD and Al-catcchin/beta-CD inclusion compounds took place at different stages, compared with the respective precursors, proving that an inclusion complexation process really occurred. (C) 2007 Published by Elsevier B.V.

Surface modification of metals by calcium carbonate thin films on a layer-by-layer polyelectrolyte matrix

A multilayer organic film containing poly(acrylic acid) and chitosan was fabricated on a metallic support by means of the layer-by-layer technique. This film was used as a template for calcium carbonate crystallization and presents two possible binding sites where the nucleation may be initiated, either calcium ions acting as counterions of the polyelectrolyte or those trapped in the template gel network formed by the polyelectrolyte chains. Calcium carbonate formation was carried out by carbon dioxide diffusion, where CO, was generated from ammonium carbonate decomposition. The CaCO3 nanocrystals obtained, formed a dense, homogeneous, and continuous film. Vaterite and calcite CaCO3 crystalline forms were detected. (c) 2007 Elsevier B.V All rights reserved.

Modeling volatile organic compounds (voc`s) adsorption onto cup-stacked carbon nanotubes (cscnt) using the linear driving force model

Modeling volatile organic compounds (voc`s) adsorption onto cup-stacked carbon nanotubes (cscnt) using the linear driving force model. Volatile organic compounds (VOC`s) are an important category of air pollutants and adsorption has been employed in the treatment (or simply concentration) of these compounds. The current study used an ordinary analytical methodology to evaluate the properties of a cup-stacked nanotube (CSCNT), a stacking morphology of truncated conical graphene, with large amounts of open edges on the outer surface and empty central channels. This work used a Carbotrap bearing a cup-stacked structure (composite); for comparison, Carbotrap was used as reference (without the nanotube). The retention and saturation capacities of both adsorbents to each concentration used (1, 5, 20 and 35 ppm of toluene and phenol) were evaluated. The composite performance was greater than Carbotrap; the saturation capacities for the composite was 67% higher than Carbotrap (average values). The Langmuir isotherm model was used to fit equilibrium data for both adsorbents, and a linear driving force model (LDF) was used to quantify intraparticle adsorption kinetics. LDF was suitable to describe the curves.

Shared structural determinants for the calcium-independent liposome membrane permeabilization and sarcolemma depolarization in Bothropstoxin-I, a LYS49-PLA(2) from the venom of Bothrops jararacussu

The structural determinants of myotoxicity of bothropstoxin-I (BthTX-I), a Lys49 phospholipase A(2) from Bothrops jararacussu venom, were studied by measuring the resting membrane potential in the mouse phrenic nerve-diaphragm preparation. This method proved to be around 100-fold more sensitive than the creatine kinase release assay, and was used to evaluate a total of 31 site-directed BthTX-I alanine scanning mutants. Mutants that reduced the resting membrane potential were located in a surface patch defined by residues in the C-terminal loop (residues 115-129), positions 37-39 in the membrane interfacial recognition surface (Y46 and K54), and residue K93. These results expand the known structural determinants of the biological activity as evaluated by previous creatine kinase release experiments. Furthermore, a strong correlation is observed between the structural determinants of sarcolemma depolarization and calcium-independent disruption of liposome membranes, suggesting that a common mechanism of action underlies the permeabilization of the biological and model membranes. (C) 2009 Elsevier Ltd. All rights reserved.

Detrusor overactivity is associated with downregulation of large-conductance calcium- and voltage-activated potassium channel protein

Chang S, Gomes CM, Hypolite JA, Marx J, Alanzi J, Zderic SA, Malkowicz B, Wein AJ, Chacko S. Detrusor overactivity is associated with downregulation of large-conductance calcium-and voltage-activated potassium channel protein. Am J Physiol Renal Physiol 298: F1416-F1423, 2010. First published April 14, 2010; doi: 10.1152/ajprenal.00595.2009.-Large-conductance voltage-and calcium-activated potassium (BK) channels have been shown to play a role in detrusor overactivity (DO). The goal of this study was to determine whether bladder outlet obstructioninduced DO is associated with downregulation of BK channels and whether BK channels affect myosin light chain 20 (MLC(20)) phosphorylation in detrusor smooth muscle (DSM). Partial bladder outlet obstruction (PBOO) was surgically induced in male New Zealand White rabbits. The rabbit PBOO model shows decreased voided volumes and increased voiding frequency. DSM from PBOO rabbits also show enhanced spontaneous contractions compared with control. Both BK channel alpha- and beta-subunits were significantly decreased in DSM from PBOO rabbits. Immunostaining shows BK beta mainly expressed in DSM, and its expression is much less in PBOO DSM compared with control DSM. Furthermore, a translational study was performed to see whether the finding discovered in the animal model can be translated to human patients. The urodynamic study demonstrates several overactive DSM contractions during the urine-filling stage in benign prostatic hyperplasia (BPH) patients with DO, while DSM is very quiet in BPH patients without DO. DSM biopsies revealed significantly less BK channel expression at both mRNA and protein levels. The degree of downregulation of the BK beta-subunit was greater than that of the BK alpha-subunit, and the downregulation of BK was only associated with DO, not BPH. Finally, the small interference (si) RNA-mediated downregulation of the BK beta-subunit was employed to study the effect of BK depletion on MLC(20) phosphorylation. siRNA-mediated BK channel reduction was associated with an increased MLC(20) phosphorylation level in cultured DSM cells. In summary, PBOO-induced DO is associated with downregulation of BK channel expression in the rabbit model, and this finding can be translated to human BPH patients with DO. Furthermore, downregulation of the BK channel may contribute to DO by increasing the basal level of MLC(20) phosphorylation.

Fibroblast Growth Factor 23 in Hemodialysis Patients: Effects of Phosphate Binder, Calcitriol and Calcium Concentration in the Dialysate

Background: Fibroblast growth factor 23 (FGF23) concentrations increase early in chronic kidney disease (CKD), and the influence of current CKD-mineral and bone disorder (MBD) therapies on serum FGF23 levels is still under investigation. Methods: In this post-hoc analysis of a randomized clinical trial, phosphate binders and calcitriol were washed out of 72 hemodialysis patients who were then submitted to bone biopsy, coronary tomography and biochemical measures, including FGF23. They were randomized to receive sevelamer or calcium acetate for 1 year and the prescription of calcitriol and the calcium concentration in the dialysate were adjusted according to serum calcium, phosphate and PTH and bone biopsy diagnosis. Results: At baseline, bone biopsy showed that 58.3% had low-turnover bone disease, whereas 38.9% had high-turnover bone disease, with no significant differences between them with regard to FGF23. Median baseline FGF23 serum levels were elevated and correlated positively with serum phosphate. After 1 year, serum FGF23 decreased significantly. Repeated measures ANOVA analysis showed that the use of a 3.5-mEq/l calcium concentration in the dialysate, as well as the administration of calcitriol and a calcium-based phosphate binder were associated with higher final serum FGF23 levels. Conclusions: Taken together, our results confirm that the current CKD-MBD therapies have an effect on serum levels of FGF23. Since FGF23 is emerging as a potential treatment target, our findings should be taken into account in the decision on how to manage CKD-MBD therapy. Copyright (C) 2010 S. Karger AG, Basel

Relation of Aortic Valve Calcium Detected by Cardiac Computed Tomography to All-Cause Mortality

Aortic valve calcium (AVC) can be quantified on the same computed tomographic scan as coronary artery calcium (CAC). Although CAC is an established predictor of cardiovascular events, limited evidence is available for an independent predictive value for AVC. We studied a cohort of 8,401 asymptomatic subjects (mean age 53 10 years, 69% men), who were free of known coronary heart disease and were undergoing electron beam computed tomography for assessment of subclinical atherosclerosis. The patients were followed for a median of 5 years (range 1 to 7) for the occurrence of mortality from any cause. Multivariate Cox regression models were developed to predict all-cause mortality according to the presence of AVC. A total of 517 patients (6%) had AVC on electron beam computed tomography. During follow-up, 124 patients died (1.5%), for an overall survival rate of 96.1% and 98.7% for those with and without AVC, respectively (hazard ratio 3.39, 95% confidence interval 2.09 to 5.49). After adjustment for age, gender, hypertension, dyslipidemia, diabetes mellitus, smoking, and a family history of premature coronary heart disease, AVC remained a significant predictor of mortality (hazard ratio 1.82, 95% confidence interval 1.11 to 2.98). Likelihood ratio chi-square statistics demonstrated that the addition of AVC contributed significantly to the prediction of mortality in a model adjusted for traditional risk factors (chi-square = 5.03, p = 0.03) as well as traditional risk factors plus the presence of CAC (chi-square = 3.58, p = 0.05). In conclusion, AVC was associated with increased all-cause mortality, independent of the traditional risk factors and the presence of CAC. (C) 2010 Published by Elsevier Inc. (Am J Cardiol 2010;106:1787-1791)

Fluid Resuscitation With Isotonic or Hypertonic Saline Solution Avoids Intraneural Calcium Influx After Traumatic Brain Injury Associated With Hemorrhagic Shock

Background: Calcium is one of the triggers involved in ischemic neuronal death. Because hypotension is a strong predictor of outcome in traumatic brain injury (TBI), we tested the hypothesis that early fluid resuscitation blunts calcium influx in hemorrhagic shock associated to TBI. Methods: Fifteen ketamine-halothane anesthetized mongrel dogs (18.7 kg +/- 1.4 kg) underwent unilateral cryogenic brain injury. Blood was shed in 5 minutes to a target mean arterial pressure of 40 mm Hg to 45 mm Hg and maintained at these levels for 20 minutes (shed blood volume = 26 mL/kg +/- 7 mL/kg). Animals were then randomized into three groups: CT (controls, no fluid resuscitation), HS (7.5% NaCl, 4 mL/kg, in 5 minutes), and LR (lactate Ringer`s, 33 mL/kg, in 15 minutes). Twenty minutes later, a craniotomy was performed and cerebral biopsies were obtained next to the lesion (""clinical penumbra"") and from the corresponding contralateral side (""lesion`s mirror"") to determine intracellular calcium by fluorescence signals of Fura-2-loaded cells. Results: Controls remained hypotensive and in a low-flow state, whereas fluid resuscitation improved hemodynamic profile. There was a significant increase in intracellular calcium in the injured hemisphere in CT (1035 nM +/- 782 nM), compared with both HS (457 nM +/- 149 nM, p = 0.028) and LR (392 nM +/- 178 nM, p = 0.017), with no differences between HS and LR (p = 0.38). Intracellular calcium at the contralateral, uninjured hemisphere was 438 nM +/- 192 nM in CT, 510 nM +/- 196 nM in HS, and 311 nM +/- 51 nM in LR, with no significant differences between them. Conclusion: Both small volume hypertonic saline and large volume lactated Ringer`s blunts calcium influx in early stages of TBI associated to hemorrhagic shock. No fluid resuscitation strategy promotes calcium influx and further neural damage.

Calcium intake and metabolic bone disease after eight years of Roux-en-Y gastric bypass

Background Roux-en-Y gastric bypass (RYGBP) has been found to be the most efficient way to lose weight and maintain the weight loss in morbid obesity. However, with the formation of a new stomach and the modification of intestinal anatomy, there are significant changes on physiological properties of these organs that lead to nutrient deficiency, including calcium. The objectives of this study were to evaluate calcium intake, bone metabolism, and prevalence of metabolic bone disease in women subjected to RYGBP after 8 years. Methods Food frequency questionnaire and 3-day dietary recall, laboratory tests of bone metabolism and bone mineral density were accessed. Results Calcium intake was below the recommendation in all women. Serum PTH and alkaline phosphatase were elevated, whereas vitamin D and urinary calcium were significantly lower. Also, a higher prevalence of metabolic bone disease than the one expected for the normal population at the same age was noted. Conclusion These data suggest that metabolic bone disease could be a complication of this type of surgery.

Anti-leishmanial effects of purified compounds from aerial parts of Baccharis uncinella C. DC. (Asteraceae)

Species of Baccharis exhibit antibiotic, antiseptic, wound-healing, and anti-protozoal properties, and have been used in the traditional medicine of South America for the treatment of several diseases. In the present work, the fractionation of EtOH extract from aerial parts of Baccharis uncinella indicated that the isolated compounds caffeic acid and pectolinaringenin showed inhibitory activity against Leishmania (L.) amazonensis and Leishmania (V.) braziliensis promastigotes, respectively. Moreover, amastigote forms of both species were highly sensible to the fraction composed by oleanolic + ursolic acids and pectolinaringenin. Caffeic acid also inhibited amastigote forms of L. (L.) amazonensis, but this effect was weak in L. (V.) braziliensis amastigotes. The treatment of infected macrophages with these compounds did not alter the levels of nitrates, indicating a direct effect of the compounds on amastigote stages. The results presented herein suggest that the active components from B. uncinella can be important to the design of new drugs against American tegumentar leishmaniases.