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Find video protocols related to scientific articles indexed in Pubmed.
National Trends in Burn and Inhalation Injury in Burn Patients: Results of Analysis of the Nationwide Inpatient Sample Database.
J Burn Care Res
PUBLISHED: 06-12-2014
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To describe national trends in prevalence, demographics, hospital length of stay (LOS), hospital charges, and mortality for burn patients with and without inhalational injury and to compare to the National Burn Repository. Burns and inhalation injury cause considerable mortality and morbidity in the United States. There remains insufficient reporting of the demographics and outcomes surrounding such injuries. The National Inpatient Sample database, the nation's largest all-payer inpatient care data repository, was utilized to select 506,628 admissions for burns from 1988 to 2008 based on ICD-9-CM recording. The data were stratified based on the extent of injury (%TBSA) and presence or absence of inhalational injury. Inhalation injury was observed in only 2.2% of burns with <20% TBSA but 14% of burns with 80 to 99% TBSA. Burn patients with inhalation injury were more likely to expire in-hospital compared to those without (odds ratio, 3.6; 95% confidence interval, 2.7-5.0; P < .001). Other factors associated with higher mortality were African-American race, female sex, and urban practice setting. Patients treated at rural facilities and patients with hyperglycemia had lower mortality rates. Each increase in percent of TBSA of burns increased LOS by 2.5%. Patients with burns covering 50 to 59% of TBSA had the longest hospital stay at a median of 24 days (range, 17-55). The median in-hospital charge for a burn patient with inhalation injury was US$32,070, compared to US$17,600 for those without. Overall, patients who expired from burn injury accrued higher in-hospital charges (median, US$50,690 vs US$17,510). Geographically, California and New Jersey were the states with the highest charges whereas Vermont and Maryland were states with the lowest charges. The study analysis provides a broad sampling of nationwide demographics, LOS, and in-hospital charges for patients with burns and inhalation injury.
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Fertility and uterine hemodynamic in cows after artificial insemination with semen assessed by fluorescent probes.
Theriogenology
PUBLISHED: 06-09-2014
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Fluorescent probes (propidium iodide, Hoechst 33342, fluorescein isothiocyanate-conjugated Pisum sativum agglutinin, and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide) were used to simultaneously evaluate the integrity of plasma and acrosomal membranes as well as mitochondrial membrane function in cryopreserved bovine semen and to verify its influence on fertility and postinsemination uterine vascularization. One hundred eighty-two Nellore cows were distributed for artificial insemination (AI) using semen batches separated according to the cell percentage presenting intact plasma membrane, intact acrosome, and high mitochondrial function (IPIAH): group G (44.5% IPIAH, n = 68), group M (23.0% IPIAH, n = 56), and group R (8.5% IPIAH, n = 58). The uterine hemodynamic was evaluated by Doppler sonogram in three periods: 30 hours before AI, 4 and 24 hours after AI were considered the resistance index and the uterine vascularization score. The pregnancy rate of group G (64.7%) was greater (P > 0.05) compared with group R (36.2%), but both did not differ from group M (50.0%). There was no effect (P > 0.05) of semen quality on uterine vascularization. Greater vascularization was noticed 4 hours after AI than 30 hours before and 24 hours after AI. Semen evaluation using fluorescent probes contributes to predicting fertilizing potential of semen. The use of semen with less percentage of IPIAH sperm does not alter uterine hemodynamic in cows.
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In vitro and in vivo analysis of the antithrombotic and toxicological profile of new antiplatelets N-acylhydrazone derivatives and development of nanosystems: determination of novel NAH derivatives antiplatelet and nanotechnological approach.
Thromb. Res.
PUBLISHED: 04-04-2014
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Cardiovascular diseases are the most frequent cause of morbidity and mortality worldwide. Among the most important cardiovascular diseases are atherothrombosis and venous thromboembolism that present platelet aggregation as a key event. Currently, the commercial antiplatelet agents display several undesirable effects, which prompt the search for new compounds with better therapeutic index, more efficient body distribution and mechanism.
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A meta-analysis of the effects of fragmentation on herbivorous insects.
Environ. Entomol.
PUBLISHED: 03-31-2014
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We reviewed the evidence for the effects of fragmentation on insects and plants by conducting a meta-analysis for the effects of artificial forest edge formation on insect herbivore abundance, herbivore richness, and plant herbivory, with data pooled from 31 studies and 159 independent comparisons. Hedge's d was used as the metric to combine all studies. Edge formation exhibited strong effects on plant herbivory rates, as edge plants exhibited 70% more damage than interior plants. Edges also increased herbivore abundance by 14% and herbivore richness by almost 65%, and effects of edge formation were stronger for Lepidoptera (mainly caterpillars) and Orthoptera. Edge effects were also stronger for forested ecosystems compared with open habitats and for temperate regions. Because the studies here evaluated did not simultaneously evaluate bottom-up and top-down factors, the mechanisms responsible for the patterns found cannot be properly addressed, although variation in host plant chemistry, relaxation of pressure exerted by natural enemies, or both, can be suggested as potential factors explaining variation in herbivory between edge and interior habitats. Higher herbivory rates on edge habitats, as shown by our meta-analytical review, have the potential to alter community composition and should be studied in detail to unravel their effects on ecosystem functioning.
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Fatty acids as a tool to understand microbial diversity and their role in food webs of Mediterranean temporary ponds.
Molecules
PUBLISHED: 02-06-2014
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Temporary Mediterranean ponds are complex ecosystems which support a high diversity of organisms that include heterotrophic microorganisms, algae, crustaceans, amphibians and higher plants, and have the potential to supply food and a resting place to migratory birds. The role of heterotrophs at the base of the food web in providing energy to the higher trophic levels was studied in temporary ponds in Central and Southern Portugal. The relative quantification of the hetero and autotrophic biomass at the base of the food web in each pond was derived from the polar fatty acid (PLFA) composition of seston through the application of the matrix factorization program CHEMTAX that used specific PLFA and their relative proportion as markers for e.g., classes of bacteria, algae and fungi. The species composition of the culturable microbial communities was identified through their fatty acid profiles. The biomass in the lower trophic level of some ponds presented an even proportion of auto to heterotrophic organisms whilst either bacteria or algae dominated in others. In a selected subset of ponds, the incorporation of bacterial fatty acids was observed to occur in potentially herbivorous zooplankton crustacean. Zooplankton consumed and incorporated bacterial fatty acids into their body tissues, including into their phospholipids, which indicates that energy of heterotrophic origin contributes to the aquatic food webs of temporary ponds.
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Effect of dexamethasone on development of in vitro-produced bovine embryos.
Theriogenology
PUBLISHED: 02-05-2014
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Studies in somatic cells have shown that glucocorticoids such as dexamethasone (DEX) may trigger or prevent apoptosis depending on the cell type in culture. Because the dysregulation of apoptosis may lower in vitro embryo production efficiency, we sought to investigate the effects of supplementing IVC medium with DEX (0.1 ?g/mL) on embryo morphology, development kinetics, and apoptosis rates of in vitro-produced bovine preimplantation embryos. Embryo morphology was graded on Day 7, and development rates were assessed on Days 4 and 7 of IVC. Apoptosis was evaluated via annexin/propidium iodide staining under fluorescence microscopy where a cell labeled with annexin, propidium iodide, or both would be considered apoptotic. An embryo was counted in the apoptosis rates, if it displayed at least one such labeled cell. Although DEX supplementation did not reduce apoptosis rates, it had a positive impact on developmental kinetics and cell number both on Days 4 and 7 of embryo culture. Presumably, such effect resulted from increased cell proliferation rather than a direct inhibition of apoptosis. Further studies may evaluate the mechanisms by which glucocorticoids may affect embryo development, as DEX supplementation could become a tool to improve in vitro embryo yield in mammalian species.
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[Axillary lymph node aspiration guided by ultrasound is effective as a method of predicting lymph node involvement in patients with breast cancer?].
Rev Bras Ginecol Obstet
PUBLISHED: 01-27-2014
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To assess the feasibility and diagnostic accuracy of preoperative ultrasound combined with ultrasound-guided fine-needle aspiration (US-FNA) cytology and clinical examination of axillary lymph node in patients with breast cancer.
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Rapid adaptation of Rhodococcus erythropolis cells to salt stress by synthesizing polyunsaturated fatty acids.
Appl. Microbiol. Biotechnol.
PUBLISHED: 01-13-2014
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Bacterial cells are known to adapt to challenging environmental conditions such as osmotic stress. However, most of the work done in this field describes the adaptation of growing populations where the new generations acquire traits that improve their ability to survive. In the present study, the responses of Rhodococcus erythropolis cells within the first 30 min after exposure to osmotic stress caused by sodium chloride were studied. The cells changed the total lipid fatty acid composition and also the net surface charge in the 30 min following exposure. Surprisingly, the cells produced a high percentage of polyunsaturated fatty acids. In the presence of 7.5 % NaCl, these polyunsaturated fatty acids, mainly eicosapentaenoic acid (C20:5?3), arachidonic acid (C20:4?6) and docosapentaenoic acid (C22:5?3), comprise more than 36 % of the total fatty acids. The possible function of these very uncommon fatty acids in bacteria could be the decrease in the number of negatively charged groups in ion channels resulting in a repellence of the NaCl.
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Population dynamics of a Salmonella lytic phage and its host: implications of the host bacterial growth rate in modelling.
PLoS ONE
PUBLISHED: 01-01-2014
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The prevalence and impact of bacteriophages in the ecology of bacterial communities coupled with their ability to control pathogens turn essential to understand and predict the dynamics between phage and bacteria populations. To achieve this knowledge it is essential to develop mathematical models able to explain and simulate the population dynamics of phage and bacteria. We have developed an unstructured mathematical model using delay-differential equations to predict the interactions between a broad-host-range Salmonella phage and its pathogenic host. The model takes into consideration the main biological parameters that rule phage-bacteria interactions likewise the adsorption rate, latent period, burst size, bacterial growth rate, and substrate uptake rate, among others. The experimental validation of the model was performed with data from phage-interaction studies in a 5 L bioreactor. The key and innovative aspect of the model was the introduction of variations in the latent period and adsorption rate values that are considered as constants in previous developed models. By modelling the latent period as a normal distribution of values and the adsorption rate as a function of the bacterial growth rate it was possible to accurately predict the behaviour of the phage-bacteria population. The model was shown to predict simulated data with a good agreement with the experimental observations and explains how a lytic phage and its host bacteria are able to coexist.
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Membrane transport systems and the biodegradation potential and pathogenicity of genus Rhodococcus.
Front Physiol
PUBLISHED: 01-01-2014
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The Rhodococcus genus contains species with remarkable ability to tolerate toxic compounds and to degrade a myriad of substrates. These substrates have to cross a distinctive cell envelope dominated by mycolic acids anchored in a scaffold of arabinogalactan covalently attached to the cell wall peptidoglycan, and a cellular membrane with phospholipids, whose composition in fatty acids can be rapidly altered in response to environmental conditions. The hydrophobic nature of the cell envelope facilitates the entrance of hydrophobic molecules but some substrates require active transport systems. Additionally, toxic compounds may also be extruded by energy spending efflux systems. In this review, physiological evidences of the use of transport systems by Rhodococcus strains and genomic studies that corroborate their existence are presented and discussed. The recently released complete genomes of several Rhodococcus strains will be the basis for an in silico correlation analysis between the efflux pumps present in the genome and their role on active transport of substrates. These transport systems will be placed on an integrative perspective of the impact of this important genus on biotechnology and health, ranging from bioremediation to antibiotic and biocide resistance.
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DHEA supplementation in ovariectomized rats reduces impaired glucose-stimulated insulin secretion induced by a high-fat diet.
FEBS Open Bio
PUBLISHED: 01-01-2014
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Dehydroepiandrosterone (DHEA) and the dehydroepiandrosterone sulfate (DHEA-S) are steroids produced mainly by the adrenal cortex. There is evidence from both human and animal models suggesting beneficial effects of these steroids for obesity, diabetes mellitus, hypertension, and osteoporosis, conditions associated with the post-menopausal period. Accordingly, we hypothesized that DHEA supplementation in ovariectomized (OVX) female rats fed a high-fat diet would maintain glucose-induced insulin secretion (GSIS) and pancreatic islet function. OVX resulted in a 30% enlargement of the pancreatic islets area compared to the control rats, which was accompanied by a 50% reduction in the phosphorylation of AKT protein in the pancreatic islets. However, a short-term high-fat diet induced insulin resistance, accompanied by impaired GSIS in isolated pancreatic islets. These effects were reversed by DHEA treatment, with improved insulin sensitivity to levels similar to the control group, and with increased serine phosphorylation of the AKT protein. These data confirm the protective effect of DHEA on the endocrine pancreas in a situation of diet-induced overweight and low estrogen concentrations, a phenotype similar to that of the post-menopausal period.
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Anatomical relationship of lingual nerve to the region of mandibular third molar.
J Oral Maxillofac Res
PUBLISHED: 01-01-2014
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This study evaluated the relationship of the lingual nerve with the adjacent anatomical structures of the mandibular third molar region, influencing the dentist to be aware of the variability of these relationships.
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Control of Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) with entomopathogenic nematodes (Rhabditida: Heterorhabditidae, Steinernematidae) in peach orchards.
Exp. Parasitol.
PUBLISHED: 08-19-2013
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Oriental fruit moth Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) is considered a major pest in temperate fruit trees, such as peach and apple. Entomopathogenic nematodes (EPNs) are regarded as viable for pest management control due to their efficiency against tortricid in these trees. The objective of this study was to evaluate the effectiveness of native EPNs from Rio Grande do Sul state against pre-pupae of G. molesta under laboratory and field conditions. In the laboratory, pre-pupae of G. molesta were placed in corrugated cardboard sheets inside glass tubes and exposed to 17 different EPNs strains at concentrations of 6, 12, 24, 48 and 60 IJs/cm(2) and maintained at 25 °C, 70 ± 10% RH and photophase of 16 h. Insect mortality was recorded 72 h after inoculation of EPNs. Steinernema rarum RS69 and Heterorhabditis bacteriophora RS33 were the most virulent strains and selected for field application (LC95 of 70.5 and 53.8 IJs/cm(2), respectively). Both strains were highly efficient under field conditions when applied in aqueous suspension directed to larvae on peach tree trunk, causing mortality of 94 and 97.0%, respectively.
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Emotional intelligence and self-efficacy: effects on psychological well-being in college students.
Span J Psychol
PUBLISHED: 07-20-2013
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The present paper examined the role of perceived emotional intelligence-EI- (measured by adaptations of the Trait Meta-Mood Scale - TMMS, Salovey, Mayer, Goldman, Turvey, & Palfai, 1995) as a predictor of life satisfaction and mental health. We explored the unique contribution of EI dimensions (Attention, Clarity and Repair) on individuals psychological well-being, after controlling for the influence of general self-efficacy and socio-demographic variables (age, gender and culture). Data was collected from a sample of 1078 Spanish, Mexican, Portuguese and Brazilian undergraduate students (M age = 22.98; SD = 6.73) and analyzed using hierarchical multiple regressions. Results indicated that overall EI dimensions (especially Clarity and Repair) accounted for unique variance on psychological well-being above and beyond general self-efficacy and socio-demographic characteristics. These findings provide additional support for the validity of perceived EI, and suggests that EI components contribute to important well-being criteria independently from well-known constructs such as self-efficacy.
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Experimental evidence of twin fast metastable H(2(2)S) atoms from dissociation of cold H2 induced by electrons.
Phys. Rev. Lett.
PUBLISHED: 07-05-2013
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We report the direct detection of two metastable H(2^{2}S) atoms coming from the dissociation of a single cold H(2) molecule, in coincidence measurements. The molecular dissociation was induced by electron impact in order to avoid limitations by the selection rules governing radiative transitions. Two detectors, placed close to the collision center, measure the neutral metastable H(2(2)S) through a localized quenching process, which mixes the H(2^{2}S) state with the H(2^{2}P), leading to a Lyman-? detection. Our data show the accomplishment of a coincidence measurement which proves for the first time the existence of the H(2(2)S)-H(2(2)S) dissociation channel.
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meso-Tetraphenylbenzoporphyrin-2(2),2(3)-dicarboxylic anhydride: a platform to benzoporphyrin derivatives.
J. Org. Chem.
PUBLISHED: 06-21-2013
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A method to synthesize meso-tetraphenylbenzoporphyrin-2(2),2(3)-dicarboxylic anhydride is reported. This compound reacts with alkylamines and arylamines to afford the corresponding "phthalimides" in moderate to excellent yields. The reaction of the title compound with benzene-1,4-diamine or with benzene-1,3-diamine yields the corresponding N,N-(phenylene)bisphthalimides, whereas with benzene-1,2-diamine or naphthalene-1,8-diamine it affords heterocyclic-fused porphyrins. Molecular mechanics simulations elucidates the multiplicity of signals observed in the NMR spectra of the N,N-(1,4-phenylene)bisphthalimide 11. This molecule exhibits two preferential conformations corresponding to a coplanar and an almost perpendicular arrangement of the benzoporphyrin units relative to the central benzenic ring.
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Leptin modulates norepinephrine-mediated melatonin synthesis in cultured rat pineal gland.
Biomed Res Int
PUBLISHED: 04-23-2013
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Pineal melatonin synthesis can be modulated by many peptides, including insulin. Because melatonin appears to alter leptin synthesis, in this work we aimed to investigate whether leptin would have a role on norepinephrine- (NE-)mediated melatonin synthesis in cultured rat pineal glands. According to our data, cultured rat pineal glands express leptin receptor isoform b (Ob-Rb). Pineal expression of Ob-Rb mRNA was also observed in vivo. Administration of leptin (1 nM) associated with NE ( 1 µM) reduced melatonin content as well as arylalkylamine-N-acetyl transferase (AANAT) activity and expression in cultured pineal glands. Leptin treatment per se induced the expression of STAT3 in cultured pineal glands, but STAT3 does not participate in the leptin modulation of NE-mediated pineal melatonin synthesis. In addition, the expression of inducible cAMP early repressor (ICER) was further induced by leptin challenge when associated with NE. In conclusion, leptin inhibition of pineal melatonin synthesis appears to be mediated by a reduction in AANAT activity and expression as well as by increased expression of Icer mRNA. Peptidergic signaling within the pineal gland appears to be one of the most important signals which modulates melatonin synthesis; leptin, as a member of this system, is not an exception.
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A suggested classification for two groups of Campylobacter myoviruses.
Arch. Virol.
PUBLISHED: 04-23-2013
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Most Campylobacter bacteriophages isolated to date have long contractile tails and belong to the family Myoviridae. Based on their morphology, genome size and endonuclease restriction profile, Campylobacter phages were originally divided into three groups. The recent genome sequencing of seven virulent campylophages reveal further details of the relationships between these phages at the genome organization level. This article details the morphological and genomic features among the campylophages, investigates their taxonomic position, and proposes the creation of two new genera, the "Cp220likevirus" and "Cp8unalikevirus" within a proposed subfamily, the "Eucampyvirinae"
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Effect of cis-9,trans-11 and trans-10,cis-12 isomers of conjugated linoleic acid on the integrity and functionality of cryopreserved bovine spermatozoa.
Cryobiology
PUBLISHED: 04-03-2013
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Plasma membranes of sperm subjected to low temperatures undergo changes in their structure and permeability. The addition of fatty acids in semen cryopreservation media may influence the sperm motility after thawing, possibly by maintaining the membrane fluidity due to their incorporation in lipid bilayers. In this work, different concentrations of the isomers cis-9,trans-11 and trans-10,cis-12 of conjugated linoleic acid (CLA) were added in the cryopreservation medium of bovine sperm. Four Jersey bulls were used, and the ejaculates were processed as a pool. The Tris-based extender (Dilutris®) was supplemented with 20% egg yolk (MB). The treatments with CLA (Luta-CLA®), which had oily presentation, were prepared from MB with addition of 1% sodium lauryl sulfate, and denominated MBL. The concentrations of CLA tested were 50, 100, and 150 ?M. The motility characteristics of the post-thaw semen were analyzed by computerized analysis system (CASA), and plasma membrane integrity and acrosomal and mitochondrial function assessed by the association of the fluorescent probes propidium iodide, fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (FITC-PSA), JC-1 and Hoechst 33342. No significant differences were observed among treatments, excepting for a decreased mitochondrial potential of cells treated with 150 ?M CLA. The addition of CLA, at the concentrations used, showed no advantages on the integrity and functionality of bovine sperm submitted to cryopreservation.
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Bacterial diversity assessed by cultivation-based techniques shows predominance of Staphylococccus species on coins collected in Lisbon and Casablanca.
FEMS Microbiol. Ecol.
PUBLISHED: 03-19-2013
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Money is usually considered a source of infections, yet survival of bacteria on dry metal surfaces is limited. The aim of this work was to assess the bacterial numbers and diversity on coins collected in Casablanca and Lisbon as these two cities, on different continents and only 585 km apart, have diverse cultural habitats, but have similar climate. A cultivation-based characterisation of the bacterial community showed that a relatively low number of cells per area of coin were found on both Moroccan Dirhams and Euros (0.014 and 0.125 colony-forming units (CFU) mm(-2) , respectively). Most of the bacterial isolates were located near the rim of the coins, and coins collected in Europe contained more CFU/area of coin. Coins collected in Europe and transported in pockets presented a higher number of bacterial isolates (maximum 0.125 CFU mm(-2) ) than coins transported in wallets (maximum 0.042 CFU mm(-2) ), regardless of the gender of the person transporting them, suggesting that temperature and moisture might be key parameters for bacterial survival on metallic coins. Bacterial diversity was higher for coins collected in Casablanca relative to coins collected in Lisbon, and there was no evidence that it was dependent on the gender of the person transporting the coins or the place of transport (pockets or wallets). Curiously, the percentage of Staphylococcus strains was 44% of the total isolates on both currencies.
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Activity of eight strains of entomopathogenic nematodes (Rhabditida: Steinernematidae, Heterorhabditidae) against five stored product pests.
Exp. Parasitol.
PUBLISHED: 03-13-2013
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Stored product pests are responsible for losses that can amount 10% during cereal storage in the world. Aiming to find an alternative method to the chemicals used for the stored-product pests, eight strains of entomopathogenic nematodes (EPNs) were tested against five species of stored product pests. The bioassays were conducted in microtubes containing paper, inoculated with EPNs and insect diet. All the insect species were susceptible to the EPNs strains. Anagasta kuehniella and Tenebrio molitor larvae and Acanthoscelides obtectus adults were highly sensitive to the higher doses with most species and/or strains of EPNs. Adults of Sitophilus oryzae and Sitophilus zeamais were relatively less sensitive to all EPNs. Therefore, EPNs show as potential control agents for stored products pests in prophylactic applications in warehouses.
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Evaluation of efficacy of 18 strains of entomopathogenic nematodes (Rhabditida) against Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) under laboratory conditions.
Exp. Parasitol.
PUBLISHED: 02-05-2013
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Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in grapevine crops in Brazil and other countries. The mealybug grows in roots and leaves of the grapes. Entomopathogenic nematodes (EPNs) are efficient control agents against insects associated to the soil and could be applied with the same equipment used for chemical insecticides. The aim of this study was to select effective EPNs for controlling P. citri females in laboratory conditions (25±1°C, UR 60±10%). We tested 17 native [Steinernema rarum (6 strains), Steinernema glaseri, Steinernema feltiae, Steinernema riobrave, Steinernema sp., Heterorhabditis bacteriophora (7 strains)] and only one exotic strain (Steinernema carpocapsae ALL). The bioassays were done on Petri dishes infested with females of P. citri, which were sprayed with EPNs juveniles. The strain with larger pathogenicity and virulence in laboratory was H. bacteriophora RS33 (from 69.0% to 92.2% of mortality), native of Rio Grande do Sul.
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Melatonin improves insulin sensitivity independently of weight loss in old obese rats.
J. Pineal Res.
PUBLISHED: 02-04-2013
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In aged rats, insulin signaling pathway (ISP) is impaired in tissues that play a pivotal role in glucose homeostasis, such as liver, skeletal muscle, and adipose tissue. Moreover, the aging process is also associated with obesity and reduction in melatonin synthesis from the pineal gland and other organs. The aim of the present work was to evaluate, in male old obese Wistar rats, the effect of melatonin supplementation in the ISP, analyzing the total protein amount and the phosphorylated status (immunoprecipitation and immunoblotting) of the insulin cascade components in the rat hypothalamus, liver, skeletal muscle, and periepididymal adipose tissue. Melatonin was administered in the drinking water for 8- and 12 wk during the night period. Food and water intake and fasting blood glucose remained unchanged. The insulin sensitivity presented a 2.1-fold increase both after 8- and 12 wk of melatonin supplementation. Animals supplemented with melatonin for 12 wk also presented a reduction in body mass. The acute insulin-induced phosphorylation of the analyzed ISP proteins increased 1.3- and 2.3-fold after 8- and 12 wk of melatonin supplementation. The total protein content of the insulin receptor (IR) and the IR substrates (IRS-1, 2) remained unchanged in all investigated tissues, except for the 2-fold increase in the total amount of IRS-1 in the periepididymal adipose tissue. Therefore, the known age-related melatonin synthesis reduction may also be involved in the development of insulin resistance and the adequate supplementation could be an important alternative for the prevention of insulin signaling impairment in aged organisms.
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Cellular mechanism by which estradiol protects female ovariectomized mice from high-fat diet-induced hepatic and muscle insulin resistance.
Endocrinology
PUBLISHED: 01-30-2013
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Estrogen replacement therapy reduces the incidence of type 2 diabetes in postmenopausal women; however, the mechanism is unknown. Therefore, the aim of this study was to evaluate the metabolic effects of estrogen replacement therapy in an experimental model of menopause. At 8 weeks of age, female mice were ovariectomized (OVX) or sham (SHAM) operated, and OVX mice were treated with vehicle (OVX) or estradiol (E2) (OVX+E2). After 4 weeks of high-fat diet feeding, OVX mice had increased body weight and fat mass compared with SHAM and OVX+E2 mice. OVX mice displayed reduced whole-body energy expenditure, as well as impaired glucose tolerance and whole-body insulin resistance. Differences in whole-body insulin sensitivity in OVX compared with SHAM mice were accounted for by impaired muscle insulin sensitivity, whereas both hepatic and muscle insulin sensitivity were impaired in OVX compared with OVX+E2 mice. Muscle diacylglycerol (DAG), content in OVX mice was increased relative to SHAM and OVX+E2 mice. In contrast, E2 treatment prevented the increase in hepatic DAG content observed in both SHAM and OVX mice. Increases in tissue DAG content were associated with increased protein kinase C? activation in liver of SHAM and OVX mice compared with OVX+E2 and protein kinase C? activation in skeletal muscle of OVX mice compared with SHAM and OVX+E2. Taken together, these data demonstrate that E2 plays a pivotal role in the regulation of whole-body energy homeostasis, increasing O(2) consumption and energy expenditure in OVX mice, and in turn preventing diet-induced ectopic lipid (DAG) deposition and hepatic and muscle insulin resistance.
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Tetrabenzoporphyrins: synthetic developments and applications.
Chem Soc Rev
PUBLISHED: 01-30-2013
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Tetrabenzoporphyrins have attracted considerable worldwide attention over the last few decades. Since the discovery of these pigments, chemists, biologists, medical professionals and material scientists have devoted pronounced efforts in order to develop synthetic methods and discover useful applications for these compounds. Nowadays, tetrabenzoporphyrins occupy a prominent position in porphyrin chemistry, and this review is intended to cover the main synthetic methods and applications of these compounds.
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Assessment of in vitro sperm characteristics and their importance in the prediction of conception rate in a bovine timed-AI program.
Anim. Reprod. Sci.
PUBLISHED: 01-28-2013
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The aims of this study were to assess in vivo fertility and in vitro sperm characteristics of different sires and to identify sperm variables important for the prediction of conception rate. Multiparous Nelore cows (n = 191) from a commercial farm underwent the same timed artificial insemination (timed-AI) protocol. Three batches of frozen semen from three Angus bulls were used (n = 9). A routine semen thawing protocol was performed in the laboratory to mimic field conditions. The following in vitro sperm analyses were performed: Computer Assisted Semen Analysis (CASA), Thermal Resistance Test (TRT), Hyposmotic Swelling Test (HOST), assessment of plasma and acrosomal membrane integrity, assessment of sperm plasma membrane stability and of lipid peroxidation by flow cytometry and assessment of sperm morphometry and chromatin structure by Toluidine Blue staining. For statistical analyses, Partial Least Squares (PLS) regression was used to explore the importance of various sperm variables in the prediction of conception rate. The following in vitro sperm variables were determined to be important predictors of conception rate: total motility (TM), progressive motility (PM), TM after 2 h of thermal incubation (TM_2 h), PM after 2 h of thermal incubation (PM_2 h), Beat Cross Frequency after 2 h of thermal incubation (BCF_2 h), percentage of rapidly moving cells after 2 h of thermal incubation (RAP_2 h), intact plasma membrane evaluated by HOST, intact plasma and acrosomal membranes evaluated by flow cytometry, intact plasma membrane suffering lipid peroxidation, major defects, total defects, morphometric width/length ratio, Fourier_0 and Fourier_2 and Chromatin Heterogeneity. We concluded that PLS regression is a suitable statistical method to identify in vitro sperm characteristics that have an important relationship with in vivo bull fertility.
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Antivenom effects of 1,2,3-triazoles against Bothrops jararaca and Lachesis muta snakes.
Biomed Res Int
PUBLISHED: 01-24-2013
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Snake venoms are complex mixtures of proteins of both enzymes and nonenzymes, which are responsible for producing several biological effects. Human envenomation by snake bites particularly those of the viperid family induces a complex pathophysiological picture characterized by spectacular changes in hemostasis and frequently hemorrhage is also seen. The present work reports the ability of six of a series of 1,2,3-triazole derivatives to inhibit some pharmacological effects caused by the venoms of Bothrops jararaca and Lachesis muta. In vitro assays showed that these compounds were impaired in a concentration-dependent manner, the fibrinogen or plasma clotting, hemolysis, and proteolysis produced by both venoms. Moreover, these compounds inhibited biological effects in vivo as well. Mice treated with these compounds were fully protected from hemorrhagic lesions caused by such venoms. But, only the B. jararaca edema-inducing activity was neutralized by the triazoles. So the inhibitory effect of triazoles derivatives against some in vitro and in vivo biological assays of snake venoms points to promising aspects that may indicate them as molecular models to improve the production of effective antivenom or to complement antivenom neutralization, especially the local pathological effects, which are partially neutralized by antivenoms.
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Genomic and proteomic characterization of the broad-host-range Salmonella phage PVP-SE1: creation of a new phage genus.
J. Virol.
PUBLISHED: 08-24-2011
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(Bacterio)phage PVP-SE1, isolated from a German wastewater plant, presents a high potential value as a biocontrol agent and as a diagnostic tool, even compared to the well-studied typing phage Felix 01, due to its broad lytic spectrum against different Salmonella strains. Sequence analysis of its genome (145,964 bp) shows it to be terminally redundant and circularly permuted. Its G+C content, 45.6 mol%, is lower than that of its hosts (50 to 54 mol%). We found a total of 244 open reading frames (ORFs), representing 91.6% of the coding capacity of the genome. Approximately 46% of encoded proteins are unique to this phage, and 22.1% of the proteins could be functionally assigned. This myovirus encodes a large number of tRNAs (n=24), reflecting its lytic capacity and evolution through different hosts. Tandem mass spectrometric analysis using electron spray ionization revealed 25 structural proteins as part of the mature phage particle. The genome sequence was found to share homology with 140 proteins of the Escherichia coli bacteriophage rV5. Both phages are unrelated to any other known virus, which suggests that an "rV5-like virus" genus should be created within the Myoviridae to contain these two phages.
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Adaptation of Rhodococcus erythropolis cells for growth and bioremediation under extreme conditions.
Res. Microbiol.
PUBLISHED: 08-05-2011
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Bioremediation of contaminated sites is rarely performed in nature under ideal growth conditions for bacteria. Extremophiles can grow at extreme values of temperature, pH, ionic strength and metal concentrations, but it may be difficult to find and isolate those possessing the required metabolic activities. In the present work, Rhodococcus erythropolis, a bacterium known to possess a large number of catabolic activities, was adapted to grow at 4-37°C, pH 3-11 and in the presence of up to 7.5% sodium chloride and 1% copper sulfate. The large majority of adapted cells were able to maintain polarization of the membrane under the most difficult conditions tested and to adjust the net surface charge. The cells changed the composition of fatty acids of the cellular membrane according to conditions endured. Changes in the relative proportion of straight, methyl and cyclopropyl saturated, unsaturated and hydroxyl substituted fatty acids were observed, as well as production of polyunsaturated fatty acids unusual in bacteria. The adapted R. erythropolis cells were able to degrade C6-C16 n-alkanes and alcohols under the previously considered extreme conditions for this bacterium.
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Mechanisms of photodynamic inactivation of a gram-negative recombinant bioluminescent bacterium by cationic porphyrins.
Photochem. Photobiol. Sci.
PUBLISHED: 07-29-2011
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Photodynamic therapy is a very promising approach to inactivate pathogenic microorganisms. The photodamage of cells involves reactive oxygen species (ROS) which are generated in situ by two main mechanisms (type I and/or type II). The mechanism responsible for the photoinactivation (PI) of a bioluminescent recombinant Escherichia coli, induced by three different cationic porphyrins, was identified in this work using a rapid method based on the monitoring of the metabolic activity of this bacterium. The inhibitory effect of the photodynamic process in the presence of a singlet oxygen quencher (sodium azide) or free radical scavengers (d-mannitol and l-cysteine) was evaluated by exposing bacterial suspensions with 0.5 ?M Tri-Py(+)-Me-PF, 5.0 ?M Tetra-Py(+)-Me or 5.0 ?M Tri-SPy(+)-Me-PF to white light. Strong bacterial protection was observed with sodium azide (100 mM) for the three cationic porphyrins. However, in the presence of Tri-Py(+)-Me-PF and Tetra-Py(+)-Me and the free radical scavengers (l-cysteine and d-mannitol) the reduction on the bacterial bioluminescence was significantly higher and similar to that obtained in their absence (5.4-6.0 log reduction). In the case of Tri-SPy(+)-Me-PF two distinct behaviours were observed when l-cysteine and d-mannitol were used as free radical scavengers: while the presence of l-cysteine (100 mM) lead to a bacterial protection similar to the one observed with sodium azide, in the presence of d-mannitol only a small protection was detected. The high inhibition of the PS activity by l-cysteine is not due to its radical scavenger ability but due to the singlet oxygen quenching by the sulfanyl group (-SH). In fact, the photodecomposition of 1,3-diphenylisobenzofuran in the presence of Tri-SPy(+)-Me-PF is completely suppressed when l-cysteine is present. The results obtained in this study suggest that singlet oxygen (type II mechanism) plays a very important role over free radicals (type I mechanism) on the PI process of the bioluminescent E. coli by Tri-Py(+)-Me-PF, Tetra-Py(+)-Me and Tri-SPy(+)-Me-PF. Although the use of scavengers is an adequate and simple approach to evaluate the relative importance of the two pathways, it is important to choose scavengers which do not interfere in both PI mechanisms. Sodium azide and d-mannitol seem to be good oxygen and free radical quenchers, respectively, to study the PI mechanisms by porphyrinic photosensitizers.
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Recent achievements on siderophore production and application.
Recent Pat Biotechnol
PUBLISHED: 06-06-2011
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Iron is the most abundant chemical element on Earth but its most common oxidation state is Fe(III) which presents a very low solubility under physiological conditions. During evolution, micro-organisms have developed sound strategies to acquire iron from both the environment and superior organisms, including direct uptake of iron ions from exogenous iron/heme sources and the synthesis of specialized Fe(III) chelators called siderophores. The present review paper aims at presenting and discussing the latest achievements in siderophore isolation and production, as well as novel applications of these molecules in therapies against iron-related diseases and in vaccines, and their application as antimicrobial agents and biosensors.
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Use of inhaler devices and asthma control in severe asthma patients at a referral center in the city of Salvador, Brazil.
J Bras Pneumol
PUBLISHED: 06-06-2011
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To evaluate the use of inhaler devices by patients with severe asthma treated via the Programa para o Controle da Asma e Rinite Alérgica na Bahia(ProAR, Bahia State Asthma and Allergic Rhinitis Control Program), recording the frequency of their errors in performing key steps and the relationship between such errors and the lack of asthma control.
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Effect of eccentric exercise velocity on akt/mtor/p70(s6k) signaling in human skeletal muscle.
Appl Physiol Nutr Metab
PUBLISHED: 05-26-2011
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It has been suggested that muscle tension plays a major role in the activation of intracellular pathways for skeletal muscle hypertrophy via an increase in mechano growth factor (MGF) and other downstream targets. Eccentric exercise (EE) imposes a greater amount of tension on the active muscle. In particular, high-speed EE seems to exert an additional effect on muscle tension and, thus, on muscle hypertrophy. However, little is known about the effect of EE velocity on hypertrophy signaling. This study investigated the effect of acute EE-velocity manipulation on the Akt/mTORCI/p70(S6K) hypertrophy pathway. Twenty subjects were assigned to either a slow (20°·s(-1); ES) or fast EE (210°·s(-1); EF) group. Biopsies were taken from vastus lateralis at baseline (B), immediately after (T1), and 2 h after (T2) the completion of 5 sets of 8 repetitions of eccentric knee extensions. Akt, mTOR, and p70(S6K) total protein were similar between groups, and did not change postintervention. Further, Akt and p70(S6K) protein phosphorylation were higher at T2 than at B for ES and EF. MGF messenger RNA was similar between groups, and only significantly higher at T2 than at B in ES. The acute manipulation of EE velocity does not seem to differently influence intracellular hypertrophy signaling through the Akt/mTORCI/p70S6K pathway.
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Transcutaneous electrical nerve stimulation after coronary artery bypass graft surgery.
Rev Bras Cir Cardiovasc
PUBLISHED: 05-18-2011
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After cardiac surgery, patients have a limitation in respiratory muscle strength, which favors the appearing of pulmonary complications.
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Burkholderia cenocepacia phenotypic clonal variation during a 3.5-year colonization in the lungs of a cystic fibrosis patient.
Infect. Immun.
PUBLISHED: 05-02-2011
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Chronic lung infection is the major cause of morbidity and premature mortality in cystic fibrosis (CF) patients. Bacteria of the Burkholderia cepacia complex are the most threatening pathogens in CF, and a better understanding of how these bacteria adapt to the CF airway environment and resist the host defense mechanisms and therapeutically administered antibiotics is crucial. To provide clues to the adaptive strategies adopted by Burkholderia cenocepacia during long-term colonization, we carried out a phenotypic assessment of 11 clonal variants obtained at the major Portuguese CF Center in Lisbon from sputa of the same CF patient during 3.5 years of colonization of the lungs, until the patients death with cepacia syndrome. Phenotypic characterization included susceptibility assays against different classes of antimicrobials and characterization of cell motility, cell hydrophobicity and zeta potential, colony and cell morphology, fatty acid composition, growth under iron limitation/load conditions, exopolysaccharide production, and size of the biofilms formed. The results suggest the occurrence of clonal expansion during long-term colonization. For a number of the characteristics tested, no isolation time-dependent consistent alteration pattern could be identified. However, the values for antimicrobial susceptibility and swarming motility for the first B. cenocepacia isolate, thought to have initiated the infection, were consistently above those for the clonal variants obtained during the course of infection, and the opposite was found for the zeta potential. The adaptive strategy for long-term colonization, described here for the first time, involved the alteration of membrane fatty acid composition, in particular a reduction of the degree of fatty acid saturation, in the B. cenocepacia variants retrieved, along with the deterioration of pulmonary function and severe oxygen limitation.
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Effects of adrenal hormones on the expression of adiponectin and adiponectin receptors in adipose tissue, muscle and liver.
Steroids
PUBLISHED: 04-20-2011
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Adiponectin, an insulin-sensitive hormone that is primarily synthesized in adipose tissue, exerts its effects by binding to two receptors, adipoR1 and adipoR2. Little is known regarding the effects of glucocorticoids on the expression of adiponectin receptors.
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Dehydroepiandrosterone protects against oxidative stress-induced endothelial dysfunction in ovariectomized rats.
J. Physiol. (Lond.)
PUBLISHED: 03-14-2011
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Cardiovascular disease is less frequent in premenopausal women than in age-matched men or postmenopausal women. Moreover, the marked age-related decline in serum dehydroepiandrosterone (DHEA) level has been associated to cardiovascular disease. The aim of this study was to evaluate the effects of DHEA treatment on vascular function in ovariectomized rats. At 8 weeks of age, female Wistar rats were ovariectomized (OVX) or sham (SHAM) operated and 8 weeks after surgery both groups were treated with vehicle or DHEA (10mg kg?¹ week?¹) for 3 weeks. Aortic rings were used to evaluate the vasoconstrictor response to phenylephrine (PHE) and the relaxation responses to acetylcholine (ACh) and sodium nitroprusside (SNP). Tissue reactive oxygen species (ROS) production and SOD, NADPH oxidase and eNOS protein expression were analysed. PHE-induced contraction was increased in aortic rings from OVX compared to SHAM, associated with a reduction in NO bioavailability. Furthermore, the relaxation induced by ACh was reduced in arteries from OVX, while SNP relaxation did not change. The incubation of aortic rings with SOD or apocynin restored the enhanced PHE-contraction and the impaired ACh-relaxation only in OVX. DHEA treatment corrected the increased PHE contraction and the impaired ACh-induced relaxation observed in OVX by an increment in NO bioavailability and decrease in ROS production. Besides, DHEA treatment restores the reduced Cu/Zn-SOD protein expression and eNOS phosphorylation and the increased NADPH oxidase protein expression in the aorta of OVX rats. The present results suggest an important action of DHEA, improving endothelial function in OVX rats by acting as an antioxidant and enhancing the NO bioavailability.
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Alterations of NADPH oxidase activity in rat pancreatic islets induced by a high-fat diet.
Pancreas
PUBLISHED: 01-06-2011
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The aim of this study was to evaluate the effect of a high-fat diet (HFD) on nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in rat pancreatic islets. We investigated if changes in NADPH oxidase are connected to beta cell dysfunction reported in obese animals.
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1,3-Dioxopyrrolo[3,4-b]porphyrins: synthesis and chemistry.
Org. Lett.
PUBLISHED: 12-03-2010
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A novel 1,3-dioxopyrrolo[3,4-b]porphyrin (2) has been synthesized in 70% yield following a [4 + 2] cycloaddition reaction of pyrrolo[3,4-b]porphyrin 1 with (1)O(2). The new imide was used as a template to other 1,3-dioxopyrrolo[3,4-b]porphyrins and to the corresponding open counterparts. The UV/vis absorption spectra of the new compounds show significant red-shifts when compared with those of the nonsubstituted analogues. The structure of an imide derivative was confirmed by single-crystal X-ray diffraction.
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Functional cationic nanomagnet-porphyrin hybrids for the photoinactivation of microorganisms.
ACS Nano
PUBLISHED: 11-19-2010
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Cationic nanomagnet-porphyrin hybrids were synthesized and their photodynamic therapy capabilities were investigated against the Gram (-) Escherichia coli bacteria, the Gram (+) Enterococcus faecalis bacteria and T4-like phage. The synthesis, structural characterization, photophysical properties, and antimicrobial activity of these new materials are discussed. The results show that these new multicharged nanomagnet-porphyrin hybrids are very stable in water and highly effective in the photoinactivation of bacteria and phages. Their remarkable antimicrobial activity, associated with their easy recovery, just by applying a magnetic field, makes these materials novel photosensitizers for water or wastewater disinfection.
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Oxidative stress and inflammatory mediators contribute to endothelial dysfunction in high-fat diet-induced obesity in mice.
J. Hypertens.
PUBLISHED: 07-10-2010
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We investigated the effects of high-fat diet-induced obesity on vascular proinflammatory factors and oxidative stress on endothelium-dependent relaxation of the aorta.
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Sewage bacteriophage inactivation by cationic porphyrins: influence of light parameters.
Photochem. Photobiol. Sci.
PUBLISHED: 06-21-2010
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Photodynamic therapy has been used to inactivate microorganisms through the use of targeted photosensitizers. Although the photoinactivation of microorganisms has already been studied under different conditions, a systematic evaluation of irradiation characteristics is still limited. The goal of this study was to test how the light dose, fluence rate and irradiation source affect the viral photoinactivation of a T4-like sewage bacteriophage. The experiments were carried out using white PAR light delivered by fluorescent PAR lamps (40 W m(-2)), sun light (600 W m(-2)) and an halogen lamp (40-1690 W m(-2)). Phage suspensions and two cationic photosensitizers (Tetra-Py(+)-Me, Tri-Py(+)-Me-PF) at concentrations of 0.5, 1.0 and 5.0 microM were used. The results showed that the efficacy of the bacteriophage photoinactivation is correlated not only with the sensitizer and its concentration but also with the light source, energy dose and fluence rate applied. Both photosensitizers at 5.0 microM were able to inactivate the T4-like phage to the limit of detection for each light source and fluence rate. However, depending of the light parameters, different irradiation times are required. The efficiency of photoinactivation is dependent on the spectral emission distribution of the light sources used. Considering the same light source and a fixed light dose applied at different fluence rates, phage inactivation was significantly higher when low fluence rates were used. In this way, the light source, fluence rate and total light dose play an important role in the effectiveness of the antimicrobial photodynamic therapy and should always be considered when establishing an optimal antimicrobial protocol.
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Enzymatic and whole cell catalysis: finding new strategies for old processes.
Biotechnol. Adv.
PUBLISHED: 06-14-2010
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The use of enzymes and whole bacterial cells has allowed the production of a plethora of compounds that have been used for centuries in foods and beverages. However, only recently we have been able to master techniques that allow the design and development of new biocatalysts with high stability and productivity. Rational redesign and directed evolution have lead to engineered enzymes with new characteristics whilst the understanding of adaptation mechanisms in bacterial cells has allowed their use under new operational conditions. Bacteria able to thrive under the most extreme conditions have also provided new and extraordinary catalytic processes. In this review, the new tools available for the improvement of biocatalysts are presented and discussed.
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Bioaugmentation and biostimulation strategies to improve the effectiveness of bioremediation processes.
Biodegradation
PUBLISHED: 05-31-2010
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Bioremediation, involving bioaugmentation and/or biostimulation, being an economical and eco-friendly approach, has emerged as the most advantageous soil and water clean-up technique for contaminated sites containing heavy metals and/or organic pollutants. Addition of pre-grown microbial cultures to enhance the degradation of unwanted compounds (bioaugmentation) and/or injection of nutrients and other supplementary components to the native microbial population to induce propagation at a hastened rate (biostimulation), are the most common approaches for in situ bioremediation of accidental spills and chronically contaminated sites worldwide. However, many factors like strain selection, microbial ecology, type of contaminant, environmental constraints, as well as procedures of culture introduction, may lead to their failure. These drawbacks, along with fragmented literature, have opened a gap between laboratory trials and on-field application. The present review discusses the effectiveness as well as the limitations of bioaugmentation and biostimulation processes. A summary of experimental studies both in confined systems under controlled conditions and of real case studies in the field is presented. A comparative account between the two techniques and also the current scenario worldwide for in situ biotreatment using bioaugmentation and biostimulation, are addressed.
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Scaling-up of complex whole-cell bioconversions in conventional and non-conventional media.
Biotechnol. Bioeng.
PUBLISHED: 05-27-2010
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The use of whole cells is becoming a more common approach in pharmaceutical and agrochemical industries in order to obtain pure compounds with fewer production steps, higher yields, and cleaner processes, as compared to those achieved with traditional strategies. Whole cells are often used as enzymes pools, in particular when multi-step reactions and/or co-factor regeneration are envisaged. Nonetheless, published information on the scale-up of such systems both in aqueous and in two-phase aqueous-organic systems is relatively scarce. The present work aims to evaluate suitable scale-up criteria in conventional and non-conventional medium for a whole-cell bioconversion that uses resting cells of Mycobacterium sp. NRRL B-3805 to cleave the side chain of beta-sitosterol, a poorly water-soluble substrate. The experiments were performed in 24-well microtiter plates and in 250 mL shaken flasks as orbital stirred systems, and in 300 mL stirred tanks as mechanically stirred systems. Results show that productivity yields were similar in all scales tested, when maintaining oxygen mass transfer coefficients constant in aqueous systems, or when maintaining constant volumetric power consumption in aqueous-organic two-phase systems.
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Obesity induced by high-fat diet promotes insulin resistance in the ovary.
J. Endocrinol.
PUBLISHED: 05-07-2010
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Besides the effects on peripheral energy homeostasis, insulin also has an important role in ovarian function. Obesity has a negative effect on fertility, and may play a role in the development of the polycystic ovary syndrome in susceptible women. Since insulin resistance in the ovary could contribute to the impairment of reproductive function in obese women, we evaluated insulin signaling in the ovary of high-fat diet-induced obese rats. Female Wistar rats were submitted to a high-fat diet for 120 or 180 days, and the insulin signaling pathway in the ovary was evaluated by immunoprecipitation and immunoblotting. At the end of the diet period, we observed insulin resistance, hyperinsulinemia, an increase in progesterone serum levels, an extended estrus cycle, and altered ovarian morphology in obese female rats. Moreover, in female obese rats treated for 120 days with the high-fat diet, the increase in progesterone levels occurred together with enhancement of LH levels. The ovary from high-fat-fed female rats showed a reduction in the insulin receptor substrate/phosphatidylinositol 3-kinase/AKT intracellular pathway, associated with an increase in FOXO3a, IL1B, and TNFalpha protein expression. These changes in the insulin signaling pathway may have a role in the infertile state associated with obesity.
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Vitamin E ameliorates high dose trans-dehydrocrotonin-associated hepatic damage in mice.
Nat Prod Commun
PUBLISHED: 05-04-2010
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trans-Dehydrocrotonin (t-DCTN), the diterpenoid from Croton cajucara Bentham, exhibits hypoglycemic and hypolipidemic activities, but in high doses is associated with a discrete hepatotoxicity. In the search for measures to mitigate this, pretreatment with the antioxidants N-acetylcysteine and vitamin E has been examined. Mice that received a high dose t-DCTN (100 mg/kg) manifested hepatic damage, as evidenced by significant elevations in serum ALT and AST, and hepatic GSH, and histological alterations, which could be obliterated by pretreatment with vitamin E, but not with N-acetylcysteine, possibly by creating an effective antioxidant balance.
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Insulin temporal sensitivity and its signaling pathway in the rat pineal gland.
Life Sci.
PUBLISHED: 04-23-2010
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In our previous work, we reported that the insulin potentiating effect on melatonin synthesis is regulated by a post-transcriptional mechanism. However, the major proteins of the insulin signaling pathway (ISP) and the possible pathway component recruited on the potentiating effect of insulin had not been characterized. A second question raised was whether windows of sensitivity to insulin exist in the pineal gland due to insulin rhythmic secretion pattern.
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The in vivo efficacy of two administration routes of a phage cocktail to reduce numbers of Campylobacter coli and Campylobacter jejuni in chickens.
BMC Microbiol.
PUBLISHED: 04-16-2010
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Poultry meat is one of the most important sources of human campylobacteriosis, an acute bacterial enteritis which is a major problem worldwide. Campylobacter coli and Campylobacter jejuni are the most common Campylobacter species associated with this disease. These pathogens live in the intestinal tract of most avian species and under commercial conditions they spread rapidly to infect a high proportion of the flock, which makes their treatment and prevention very difficult. Bacteriophages (phages) are naturally occurring predators of bacteria with high specificity and also the capacity to evolve to overcome bacterial resistance. Therefore phage therapy is a promising alternative to antibiotics in animal production. This study tested the efficacy of a phage cocktail composed of three phages for the control of poultry infected with C. coli and C. jejuni. Moreover, it evaluated the effectiveness of two routes of phage administration (by oral gavage and in feed) in order to provide additional information regarding their future use in a poultry unit.
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Chronic low frequency/low volume resistance training reduces pro-inflammatory cytokine protein levels and TLR4 mRNA in rat skeletal muscle.
Eur. J. Appl. Physiol.
PUBLISHED: 03-22-2010
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Skeletal muscle is the source of pro- and anti-inflammatory cytokines, and recently, it has been recognized as an important source of interleukin 6 (IL-6), a cytokine that exerts inhibitory effects on several pro-inflammatory cytokines. Although dynamic chronic resistance training has been shown to produce the known "repeated bout effect", which abolishes the acute muscle damage, performing of high-intensity resistance training has been regarded highly advisable, at least from the hypertrophy perspective. On the other hand, a more therapeutic, "non-damaging" resistance training program, mainly composed of concentric forces, low frequency/low volume of training, and the same exercise, could theoretically benefit the muscle when the main issue is to avoid muscle inflammation (as in the treatment of several "low-grade" inflammatory diseases) because the acute effect of each resistance exercise session could be diminished/avoided, at the same time that the muscle is still being overloaded in a concentric manner. However, the benefits of such "less demanding" resistance training schedule on the muscle inflammatory profile have never been investigated. Therefore, we assessed the protein expression of IL-6, TNF-alpha, IL-10, IL-10/TNF-alpha ratio, and HSP70 levels and mRNA expression of SCF(beta-TrCP), IL-15, and TLR-4 in the skeletal muscle of rats submitted to resistance training. Briefly, animals were randomly assigned to either a control group (S, n = 8) or a resistance-trained group (T, n = 7). Trained rats were exercised over a duration of 12 weeks (two times per day, two times per week). Detection of IL-6, TNF-alpha, IL-10, and HSP70 protein expression was carried out by western blotting and SCF(beta-TrCP) (SKP Cullin F-Box Protein Ligases), a class of enzymes involved in the ubiquitination of protein substrates to proteasomal degradation, IL-15, and TLR-4 by RT-PCR. Our results show a decreased expression of TNF-alpha and TLR4 mRNA (40 and 60%, respectively; p < 0.05) in the plantar muscle from trained, when compared with control rats. In conclusion, exercise training induced decreased TNF-alpha and TLR-4 expressions, resulting in a modified IL-10/TNF-alpha ratio in the skeletal muscle. These data show that, in healthy rats, 12-week resistance training, predominantly composed of concentric stimuli and low frequency/low volume schedule, down regulates skeletal muscle production of cytokines involved in the onset, maintenance, and regulation of inflammation.
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Fructose alters adiponectin, haptoglobin and angiotensinogen gene expression in 3T3-L1 adipocytes.
Nutr Res
PUBLISHED: 02-02-2010
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Fructose- or sucrose-rich diets can cause insulin resistance and increase the risk of cardiovascular disease. Adipokines are correlated with the development of these diseases in obesity. We hypothesize that fructose and sucrose induce insulin resistance via effects on adipokine gene expression in adipocytes. This study analyzed the effect of fructose or glucose on adiponectin, haptoglobin, and angiotensinogen gene expression in 3T3-L1 adipocytes. Ten days after differentiation, the cells were pretreated with serum- and glucose-free medium. Twenty-four hours later, fructose or glucose (0, 5, 10, or 20 mmol) was added into the medium, and the cells were collected after a further 24 hours. Adiponectin, haptoglobin, and angiotensinogen gene expression were determined. Adiponectin gene expression increased when 10 or 20 mmol glucose was added compared with that observed for the non-hexose-treated cells. A similar effect occurred when 5 mmol fructose was added. Glucose (10 mmol) and fructose (20 mmol) stimulated haptoglobin gene expression in 3T3-L1 adipocytes compared with 0 mmol, with glucose producing a more pronounced effect. Although 20 mmol fructose caused an increase in angiotensinogen gene expression, glucose did not. In conclusion, in this study of 2 hexoses revealed an increase in adiponectin gene expression, suggesting that the effect of a glucose-rich diet on the development of insulin resistance is not related to the effect of these hexoses on adipocyte adiponectin gene expression. However, insulin resistance and cardiovascular disease promoted by fructose-rich diets could be partially related to the effect of fructose on adiponectin and angiotensinogen gene expression.
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Production of metabolites as bacterial responses to the marine environment.
Mar Drugs
PUBLISHED: 01-28-2010
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Bacteria in marine environments are often under extreme conditions of e.g., pressure, temperature, salinity, and depletion of micronutrients, with survival and proliferation often depending on the ability to produce biologically active compounds. Some marine bacteria produce biosurfactants, which help to transport hydrophobic low water soluble substrates by increasing their bioavailability. However, other functions related to heavy metal binding, quorum sensing and biofilm formation have been described. In the case of metal ions, bacteria developed a strategy involving the release of binding agents to increase their bioavailability. In the particular case of the Fe(3+) ion, which is almost insoluble in water, bacteria secrete siderophores that form soluble complexes with the ion, allowing the cells to uptake the iron required for cell functioning. Adaptive changes in the lipid composition of marine bacteria have been observed in response to environmental variations in pressure, temperature and salinity. Some fatty acids, including docosahexaenoic and eicosapentaenoic acids, have only been reported in prokaryotes in deep-sea bacteria. Cell membrane permeability can also be adapted to extreme environmental conditions by the production of hopanoids, which are pentacyclic triterpenoids that have a function similar to cholesterol in eukaryotes. Bacteria can also produce molecules that prevent the attachment, growth and/or survival of challenging organisms in competitive environments. The production of these compounds is particularly important in surface attached strains and in those in biofilms. The wide array of compounds produced by marine bacteria as an adaptive response to demanding conditions makes them suitable candidates for screening of compounds with commercially interesting biological functions. Biosurfactants produced by marine bacteria may be helpful to increase mass transfer in different industrial processes and in the bioremediation of hydrocarbon-contaminated sites. Siderophores are necessary e.g., in the treatment of diseases with metal ion imbalance, while antifouling compounds could be used to treat man-made surfaces that are used in marine environments. New classes of antibiotics could efficiently combat bacteria resistant to the existing antibiotics. The present work aims to provide a comprehensive review of the metabolites produced by marine bacteria in order to cope with intrusive environments, and to illustrate how such metabolites can be advantageously used in several relevant areas, from bioremediation to health and pharmaceutical sectors.
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Antimicrobial photodynamic therapy: study of bacterial recovery viability and potential development of resistance after treatment.
Mar Drugs
PUBLISHED: 01-06-2010
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Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py(+)-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py(+)-Me-PF (5.0 microM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m(-2)) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 microM of Tri-Py(+)-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py(+)-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process.
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Antilonomic effects of Brazilian brown seaweed extracts.
Nat Prod Commun
PUBLISHED: 09-23-2009
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The aim of this work was to investigate the hemolysis and blood clotting activity of Lomonia obliqua venom and the ability of some Brazilian marine algal extracts (Canistrocarpus cervicornis, Stypopodium zonale and Dictyota pfaffi) to antagonize such biological activities. L. obliqua caterpillars are dangerous to human beings and envenomation symptoms are characterized by hemorrhagic, hemolytic and blood clotting disorders, and acute renal failure, which sometimes lead to the death of the victims. Through in vitro experiments we have shown that L. obliqua venom is able to clot human plasma and hemolize human erythrocytes and that the coagulation activity of the venom is inhibited by the extracts of C. cervicornis, S. zonale and D. pfaffi. In contrast, C. cervicornis and S. zonale extracts did not inhibit the hemolytic activity of L. oblqua, as did the extract of D. pfaffi. These finding indicate that marine algae may be used as antivenoms or may contribute to the development of compounds with antilonomic effects.
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Fluorometric determination of ethidium bromide efflux kinetics in Escherichia coli.
J Biol Eng
PUBLISHED: 07-29-2009
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Efflux pump activity has been associated with multidrug resistance phenotypes in bacteria, compromising the effectiveness of antimicrobial therapy. The development of methods for the early detection and quantification of drug transport across the bacterial cell wall is a tool essential to understand and overcome this type of drug resistance mechanism. This approach was developed to study the transport of the efflux pump substrate ethidium bromide (EtBr) across the cell envelope of Escherichia coli K-12 and derivatives, differing in the expression of their efflux systems.
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Synthesis, biological, and theoretical evaluations of new 1,2,3-triazoles against the hemolytic profile of the Lachesis muta snake venom.
Bioorg. Med. Chem.
PUBLISHED: 07-13-2009
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The current treatment used against envenomation by Lachesis muta venom still presents several side effects. This paper describes the synthesis, pharmacological and theoretical evaluations of new 1-arylsulfonylamino-5-methyl-1H-[1,2,3]-triazole-4-carboxylic acid ethyl esters (8a-f) tested against the hemolytic profile of the L. muta snake venom. Their structures were elucidated by one- and two-dimensional NMR techniques ((1)H, APT, HETCOR (1)J(CH) and (n)J(CH), n=2, 3) and high-resolution electrospray ionization mass spectrometry. The series of triazole derivatives significantly neutralized the hemolysis induced by L. muta crude venom presenting a dose-dependent inhibitory profile (IC(50)=30-83 microM) with 1-(4-chlorophenylsulfonylamino)-5-methyl-1H-[1,2,3]-triazole-4-carboxylic acid ethyl ester (8e) being the most potent compound. The theoretical evaluation revealed the correlation of the antiophidian profile with the coefficient distribution and density map of the Highest Occupied Molecular Orbitals (HOMO) of these molecules. The elucidation of this new series may help on designing new and more efficient antiophidian molecules.
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Combined role of extracellular matrix and chemokines on peripheral lymphocyte migration in growth hormone transgenic mice.
Brain Behav. Immun.
PUBLISHED: 07-02-2009
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Previous evidence indicated that growth hormone (GH) modulates cell migration in the thymus, and that extracellular matrix and chemokines are involved. Herein, we studied migration of peripheral lymphocytes derived from spleen and lymph nodes of GH-transgenic (GH-Tg) mice. We initially found that the relative cell numbers (normalized per gram of body weight) in lymph nodes and spleens from GH-Tg were higher at all ages tested (2-3, 7 and 12 months), as compared to wild type age-matched controls. Functionally, we found that lymphocyte migration triggered by laminin or fibronectin was enhanced in cells from GH-Tg versus control mice, independent of the organ from which the cells were derived (as ascertained in young adult animals). However, such an enhancement in migration was statistically significant only for CD4+ and CD8+ T cells from mesenteric lymph nodes. Migration of lymphocytes from mesenteric lymph nodes of GH-Tg mice, triggered by the chemokine CXCL12, in conjunction with laminin or fibronectin, was enhanced compared to lymphocytes from control mice. Rather surprisingly, the membrane levels of the corresponding extracellular matrix or chemokine receptors in peripheral lymphoid organs of GH-Tg mice did not necessarily correlate with the changes seen in migratory responses. In conclusion, our data show for the first time that GH alters lymphocyte migration in the periphery of the immune system. Considering that GH is used as an adjuvant therapeutic agent in immunodeficiencies, including AIDS, the concepts defined herein provide relevant background knowledge for future GH-related immune interventions.
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Charge effect on the photoinactivation of Gram-negative and Gram-positive bacteria by cationic meso-substituted porphyrins.
BMC Microbiol.
PUBLISHED: 04-15-2009
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In recent times photodynamic antimicrobial therapy has been used to efficiently destroy Gram (+) and Gram (-) bacteria using cationic porphyrins as photosensitizers. There is an increasing interest in this approach, namely in the search of photosensitizers with adequate structural features for an efficient photoinactivation process. In this study we propose to compare the efficiency of seven cationic porphyrins differing in meso-substituent groups, charge number and charge distribution, on the photodynamic inactivation of a Gram (+) bacterium (Enterococcus faecalis) and of a Gram (-) bacterium (Escherichia coli). The present study complements our previous work on the search for photosensitizers that might be considered good candidates for the photoinactivation of a large spectrum of environmental microorganisms.
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Gastroprotective effect of lupeol on ethanol-induced gastric damage and the underlying mechanism.
Inflammopharmacology
PUBLISHED: 03-23-2009
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The effect of lupeol, a natural pentacyclic triterpene on ethanol-induced gastric damage in mice was evaluated. The gastroprotection was assessed by determination of changes in mean gastric lesion area, quantification of mucosal non-protein sulfhydryls (NP-SH), and characterized using drugs that influence the endogenous prostaglandins, alpha(2)-adrenoceptors, nitric oxide, K(ATP)-channels, and intracellular calcium. Orally administered lupeol (3, 10, and 30 mg/kg) significantly and dose-dependently attenuated the ethanol-induced gastric damage by 39-69%, whereas the positive control N-acetylcysteine (NAC, 300 mg/kg, i.p.) afforded 32% protection. Both lupeol and NAC restored the NP-SH depleted by ethanol but the lupeol effect was only marginal. Lupeol gastroprotection was attenuated by indomethacin and L-NAME, the respective COX and NO-synthase inhibitors and was weakly sensitive to alpha(2)-adrenergic antagonist yohimbine and K(ATP)-channel blocker glibenclamide, but more profoundly to calcium blocker verapamil. These pharmacological effects of lupeol may synergistically contribute to alleviating the ethanol-associated gastric damage, which is multifactorial.
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Palmitate activates insulin signaling pathway in pancreatic rat islets.
Pancreas
PUBLISHED: 03-17-2009
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To investigate the action of palmitate on insulin receptor (IR) signaling pathway in rat pancreatic islets. The following proteins were studied: IR substrate-1 and -2 (IRS1 and IRS2), phosphatidylinositol 3-kinase, extracellular signal-regulated protein kinase-1 and -2 (ERK1/2), and signal transducer and activator of transcription 3 (STAT3).
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Chronic resistance training decreases MuRF-1 and Atrogin-1 gene expression but does not modify Akt, GSK-3beta and p70S6K levels in rats.
Eur. J. Appl. Physiol.
PUBLISHED: 03-05-2009
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Long-term adaptation to resistance training is probably due to the cumulative molecular effects of each exercise session. Therefore, we studied in female Wistar rats the molecular effects of a chronic resistance training regimen (3 months) leading to skeletal muscle hypertrophy in the plantaris muscle. Our results demonstrated that muscle proteolytic genes MuRF-1 and Atrogin-1 were significantly decreased in the exercised group measured 24 h after the last resistance exercise session (41.64 and 61.19%, respectively; P < 0.05). Nonetheless, when measured at the same time point, 4EBP-1, GSK-3beta and eIF2Bepsilon mRNA levels and Akt, GSK-3beta and p70S6K protein levels (regulators of translation initiation) were not modified. Such data suggests that if gene transcription constitutes a control point in the protein synthesis pathway this regulation probably occurs in early adaptation periods or during extreme situations leading to skeletal muscle remodeling. However, proteolytic gene expression is modified even after a prolonged resistance training regimen leading to moderate skeletal muscle hypertrophy.
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Cell wall adaptations of planktonic and biofilm Rhodococcus erythropolis cells to growth on C5 to C16 n-alkane hydrocarbons.
Appl. Microbiol. Biotechnol.
PUBLISHED: 02-24-2009
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Rhodococcus erythropolis was found to utilize C5 to C16 n-alkane hydrocarbons as sole source of carbon and energy when growing as planktonic or biofilm cells attached to polystyrene surfaces. Growth rates on even numbered were two- to threefold increased relatively to odd-numbered n-alkanes and depended on the chain length of the n-alkanes. C10-, C12-, C14-, and C16-n-alkanes gave rise to two- to fourfold increased maximal growth rates relative to C5- to C9-hydrocarbons. In reaction to the extremely poor water solubility of the n-alkanes, both planktonic and biofilm cells exhibited distinct adaptive changes. These included the production of surface active compounds and substrate-specific modifications of the physicochemical cell surface properties as expressed by the microbial adhesion to hydrocarbon- and contact angle-based hydrophobicity, as well as the zeta potential of the cells. By contrast, n-alkane-specific alterations of the cellular membrane composition were less distinct. The specificity of the observed autecological changes suggest that R. erythropolis cells may be used in the development and application of sound biocatalytic processes using n-alkanes as substrates or substrate reservoirs or for target-specific bioremediation of oils and combustibles, respectively.
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Adrenal gland injury secondary to blunt traumatic mechanisms: a marker of overall injury severity.
Endokrynol Pol
PUBLISHED: 02-19-2009
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Adrenal gland injuries (AGI) are seen increasingly frequently owing to advances in modern imaging techniques. This study describes a series of patients with blunt AGI, with the emphasis on AGI as a marker of injury severity, CT-radiographic classification of AGI and associated injury patterns.
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An evolutionarily conserved Myostatin proximal promoter/enhancer confers basal levels of transcription and spatial specificity in vivo.
Dev. Genes Evol.
PUBLISHED: 02-07-2009
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Myostatin (Mstn) is a negative regulator of skeletal muscle mass, and Mstn mutations are responsible for the double muscling phenotype observed in many animal species. Moreover, Mstn is a positive regulator of adult muscle stem cell (satellite cell) quiescence, and hence, Mstn is being targeted in therapeutic approaches to muscle diseases. In order to better understand the mechanisms underlying Mstn regulation, we searched for the genes proximal enhancer and promoter elements, using an evolutionary approach. We identified a 260-bp-long, evolutionary conserved region upstream of tetrapod Mstn and teleost mstn b genes. This region contains binding sites for TATA binding protein, Meis1, NF-Y, and for CREB family members, suggesting the involvement of cAMP in Myostatin regulation. The conserved fragment was able to drive reporter gene expression in C2C12 cells in vitro and in chicken somites in vivo; both normally express Mstn. In contrast, the reporter construct remained silent in the avian neural tube that normally does not express Mstn. This suggests that the identified element serves as a minimal promoter, harboring some spatial specificity. Finally, using bioinformatic approaches, we identified additional genes in the human genome associated with sequences similar to the Mstn proximal promoter/enhancer. Among them are genes important for myogenesis. This suggests that Mstn and these genes may form a synexpression group, regulated by a common signaling pathway.
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The use of antibiotics to improve phage detection and enumeration by the double-layer agar technique.
BMC Microbiol.
PUBLISHED: 01-20-2009
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The Double-Layer Agar (DLA) technique is extensively used in phage research to enumerate and identify phages and to isolate mutants and new phages. Many phages form large and well-defined plaques that are easily observed so that they can be enumerated when plated by the DLA technique. However, some give rise to small and turbid plaques that are very difficult to detect and count. To overcome these problems, some authors have suggested the use of dyes to improve the contrast between the plaques and the turbid host lawns. It has been reported that some antibiotics stimulate bacteria to produce phages, resulting in an increase in final titer. Thus, antibiotics might contribute to increasing plaque size in solid media.
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Evidence of the mechanism of action of Erythrina velutina Willd (Fabaceae) leaves aqueous extract.
J Ethnopharmacol
PUBLISHED: 01-17-2009
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Erythrina velutina is traditionally used for sleepiness, convulsions and nervous system excitation in Brazil. Although central effects have been reported for Erythrina velutina, little is known about its mechanism of action.
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Sitosterol bioconversion with resting cells in liquid polymer based systems.
Bioresour. Technol.
PUBLISHED: 01-05-2009
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The use of a biocompatible water-immiscible organic phase as a substrate and product pool has been acknowledged as an effective tool to overcome the low volumetric productivity of aqueous bioconversion systems involving hydrophobic compounds. The growing environmental and public health awareness is nevertheless leading to restrictions in the use of organic solvents in industrial processes, in order to render these more environmentally friendly. Different approaches are hence being assessed for the design of alternative bioconversion media, involving the use of supercritical fluids, ionic liquids and natural oils and liquid polymers, among others. In this work, the use of liquid polymers as key components in the bioconversion media for a multi-step microbial bioconversion was assessed. The model system used was the selective cleavage of the side-chain of beta-sitosterol by free resting cells of Mycobacterium sp. NRRL B-3805, a well established industrial multi-enzymatic process involving the use of nine catabolic enzymes in a fourteen-step metabolic pathway. High product yields were obtained when silicone B oil was used as substrate carrier/product pool, both in single oil and in oil:buffer two liquid phase system.
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Adaptation of Cupriavidus necator to conditions favoring polyhydroxyalkanoate production.
J. Biotechnol.
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The fatty acid (FA) composition of the bacterial membrane of Cupriavidus necator DSM 545 was assessed during the time course of two-stage fed-batch cultivations for the production of short-chain polyhydroxyalkanoates (PHA). Changes in the relative proportion of straight, methyl and cyclopropyl saturated, unsaturated, hydroxy substituted and polyunsaturated FA were observed, depending on the C sources and cultivation conditions used to favor the synthesis of poly(3-hydroxybutyrate) (P(3HB)), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) or poly(3-hydroxybutyrate-4-hydroxybutyrate-3-hydroxyvalerate) (P(3HB-4HB-3HV)), under N limiting conditions. The relative percentage of each FA class was studied using glucose or waste glycerol (GRP), as main C source for P(3HB) production. The FA profile was also assessed when GRP was used together with i) ?-butyrolactone (GBL) (precursor of 4HB monomers) for P(3HB-4HB) synthesis and ii) GBL and propionic acid (PA) (3HV precursor) to yield P(3HB-4HB-3HV). The effect of GBL and PA utilization as PHA monomer precursors on the FA profile of the cell membrane was studied under two different dissolved oxygen concentrations (DOC).
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Dose and latency effects of leucine supplementation in modulating glucose homeostasis: opposite effects in healthy and glucocorticoid-induced insulin-resistance states.
Nutrients
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Dexamethasone (DEXA) is a potent immunosupressant and anti-inflammatory agent whose main side effects are muscle atrophy and insulin resistance in skeletal muscles. In this context, leucine supplementation may represent a way to limit the DEXA side effects. In this study, we have investigated the effects of a low and a high dose of leucine supplementation (via a bolus) on glucose homeostasis, muscle mass and muscle strength in energy-restricted and DEXA-treated rats. Since the leucine response may also be linked to the administration of this amino acid, we performed a second set of experiments with leucine given in bolus (via gavage) versus leucine given via drinking water. Leucine supplementation was found to produce positive effects (e.g., reduced insulin levels) only when administrated in low dosage, both via the bolus or via drinking water. However, under DEXA treatment, leucine administration was found to significantly influence this response, since leucine supplementation via drinking water clearly induced a diabetic state, whereas the same effect was not observed when supplied via the gavage.
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