26 resultados para Molecular and Cellular Neuroscience

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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Background: The neural mobilization technique is a noninvasive method that has proved clinically effective in reducing pain sensitivity and consequently in improving quality of life after neuropathic pain. The present study examined the effects of neural mobilization (NM) on pain sensitivity induced by chronic constriction injury (CCI) in rats. The CCI was performed on adult male rats, submitted thereafter to 10 sessions of NM, each other day, starting 14 days after the CCI injury. Over the treatment period, animals were evaluated for nociception using behavioral tests, such as tests for allodynia and thermal and mechanical hyperalgesia. At the end of the sessions, the dorsal root ganglion (DRG) and spinal cord were analyzed using immunohistochemistry and Western blot assays for neural growth factor (NGF) and glial fibrillary acidic protein (GFAP). Results: The NM treatment induced an early reduction (from the second session) of the hyperalgesia and allodynia in CCI-injured rats, which persisted until the end of the treatment. On the other hand, only after the 4th session we observed a blockade of thermal sensitivity. Regarding cellular changes, we observed a decrease of GFAP and NGF expression after NM in the ipsilateral DRG (68% and 111%, respectively) and the decrease of only GFAP expression after NM in the lumbar spinal cord (L3-L6) (108%). Conclusions: These data provide evidence that NM treatment reverses pain symptoms in CCI-injured rats and suggest the involvement of glial cells and NGF in such an effect.

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The respiration of metal oxides by the bacterium Geobacter sulfurreducens requires the assembly of a small peptide (the GS pilin) into conductive filaments termed pili. We gained insights into the contribution of the GS pilin to the pilus conductivity by developing a homology model and performing molecular dynamics simulations of the pilin peptide in vacuo and in solution. The results were consistent with a predominantly helical peptide containing the conserved a-helix region required for pilin assembly but carrying a short carboxy-terminal random-coiled segment rather than the large globular head of other bacterial pilins. The electronic structure of the pain was also explored from first principles and revealed a biphasic charge distribution along the pilin and a low electronic HOMO-LUMO gap, even in a wet environment. The low electronic band gap was the result of strong electrostatic fields generated by the alignment of the peptide bond dipoles in the pilin's alpha-helix and by charges from ions in solution and amino acids in the protein. The electronic structure also revealed some level of orbital delocalization in regions of the pilin containing aromatic amino acids and in spatial regions of high resonance where the HOMO and LUMO states are, which could provide an optimal environment for the hopping of electrons under thermal fluctuations. Hence, the structural and electronic features of the pilin revealed in these studies support the notion of a pilin peptide environment optimized for electron conduction.

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Historical climatic refugia predict genetic diversity in lowland endemics of the Brazilian Atlantic rainforest. Yet, available data reveal distinct biological responses to the Last Glacial Maximum (LGM) conditions across species of different altitudinal ranges. We show that species occupying Brazil's montane forests were significantly less affected by LGM conditions relative to lowland specialists, but that pre-Pleistocene tectonics greatly influenced their geographic variation. Our conclusions are based on palaeoclimatic distribution models, molecular sequences of the cytochrome b, 16S, and RAG-1 genes, and karyotype data for the endemic frog Proceratophrys boiei. DNA and chromosomal data identify in P. boiei at least two broadly divergent phylogroups, which have not been distinguished morphologically. Cytogenetic results also indicate an area of hybridization in southern Sao Paulo. The location of the phylogeographic break broadly matches the location of a NW-SE fault, which underwent reactivation in the Neogene and led to remarkable landscape changes in southeastern Brazil. Our results point to different mechanisms underpinning diversity patterns in lowland versus montane tropical taxa, and help us to understand the processes responsible for the large number of narrow endemics currently observed in montane areas of the southern Atlantic forest hotspot. (C) 2011 Elsevier Inc. All rights reserved.

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The heart responds to sustained overload by hypertrophic growth in which the myocytes distinctly thicken or elongate on increases in systolic or diastolic stress. Though potentially adaptive, hypertrophy itself may predispose to cardiac dysfunction in pathological settings. The mechanisms underlying the diverse morphology and outcomes of hypertrophy are uncertain. Here we used a focal adhesion kinase (FAK) cardiac-specific transgenic mice model (FAK-Tg) to explore the function of this non-receptor tyrosine kinase on the regulation of myocyte growth. FAK-Tg mice displayed a phenocopy of concentric cardiac hypertrophy, reflecting the relative thickening of the individual myocytes. Moreover, FAK-Tg mice showed structural, functional and molecular features of a compensated hypertrophic growth, and preserved responses to chronic pressure overload. Mechanistically, FAK overexpression resulted in enhanced myocardial FAK activity, which was proven by treatment with a selective FAK inhibitor to be required for the cardiac hypertrophy in this model. Our results indicate that upregulation of FAK does not affect the activity of Src/ERK1/2 pathway, but stimulated signaling by a cascade that encompasses PI3K, AKT, mTOR, S6K and rpS6. Moreover, inhibition of the mTOR complex by rapamycin extinguished the cardiac hypertrophy of the transgenic FAK mice. These findings uncover a unique role for FAK in regulating the signaling mechanisms that governs the selective myocyte growth in width, likely controlling the activity of PI3K/AKT/mTOR pathway, and suggest that FAK activation could be important for the adaptive response to increases in cardiac afterload. This article is part of a Special Issue entitled "Local Signaling in Myocytes". (C) 2011 Elsevier Ltd. All rights reserved.

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Dactylotrochus cervicornis (= Tridacophyllia cervicornis Moseley, 1881), which occurs in Indo-Pacific waters between 73 and 852 m, was originally described as an astraeid but was later transferred to the Caryophylliidae. Assumed to be solitary, this species has no stolons and only one elongated fossa, and is unique among azooxanthellate scleractinians in often displaying extremely long thecal extensions that are septate and digitiform. Based on both molecular phylogenetic analyses (partial mitochondrial CO1 and 16S rDNA, and partial nuclear 28S rDNA) and morphological characteristics, we propose the transfer of D. cervicornis from the Caryophylliidae to the Agariciidae, making it the first extant representative of the latter family that is solitary and from deep water (azooxanthellate). The basal position of D. cervicornis within the agariciids implied by our analyses strengthens the case for inclusion of fossil species that were solitary, such as Trochoseris, in this family and suggests that the ancestor of this scleractinian family, extant members of which are predominantly colonial and zooxanthellate, may have been solitary and azooxanthellate.

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The expression of Langerhans cell (LC) and dermal dendritic cell (dDC) as well as T CD4+ and CD8+ immune responses was evaluated in the skin of BALB/c mice experimentally infected by L. (L.) amazonensis (La) and L. (V.) braziliensis (Lb). At 4th and 8th weeks post infection (PI), skin biopsies were collected to determine the parasite load and CD207+, CD11c+, CD4+, CD8+, iNOS+ cellular densities. Cytokine (IFN-?, IL-4 and IL-10) profiles were also analysed in draining lymph node. At 4th week, the densities of CD207+ and CD11c+ were higher in the La infection, while in the Lb infection, these markers revealed a significant increase at 8th week. At 4th week, CD4+ and CD8+ were higher in the La infection, but at 8th week, there was a substantial increase in both markers in the Lb infection. iNOS+ was higher in the Lb infection at 4th and 8th weeks. In contrast, the parasite load was higher in the La infection at 4th and 8th weeks. The concentration of IFN-? was higher in the Lb infection, but IL-4 and IL-10 were higher in the La infection at 4th and 8th weeks. These results confirm the role of the Leishmania species in the BALB/c mice disease characterized by differences in the expression of dendritic cells and cellular immune response.

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Bovine coronavirus has been associated with diarrhoea in newborn calves, winter dysentery in adult cattle and respiratory tract infections in calves and feedlot cattle. In Cuba, the presence of BCoV was first reported in 2006. Since then, sporadic outbreaks have continued to occur. This study was aimed at deepening the knowledge of the evolution, molecular markers of virulence and epidemiology of BCoV in Cuba. A total of 30 samples collected between 2009 and 2011 were used for PCR amplification and direct sequencing of partial or full S gene. Sequence comparison and phylogenetic studies were conducted using partial or complete S gene sequences as phylogenetic markers. All Cuban bovine coronavirus sequences were located in a single cluster supported by 100% bootstrap and 1.00 posterior probability values. The Cuban bovine coronavirus sequences were also clustered with the USA BCoV strains corresponding to the GenBank accession numbers EF424621 and EF424623, suggesting a common origin for these viruses. This phylogenetic cluster was also the only group of sequences in which no recombination events were detected. Of the 45 amino acid changes found in the Cuban strains, four were unique. (C) 2012 Elsevier B.V. All rights reserved.

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The diagnosis of T-cell large granular lymphocytic leukemia in association with other B-cell disorders is uncommon but not unknown. However, the concomitant presence of three hematological diseases is extraordinarily rare. We report an 88-year-old male patient with three simultaneous clonal disorders, that is, CD4+/CD8(weak) T-cell large granular lymphocytic leukemia, monoclonal gammopathy of unknown significance and monoclonal B-cell lymphocytosis. The patient has only minimal complaints and has no anemia, neutropenia or thrombocytopenia. Lymphadenopathy and hepatosplenomegaly were not present. The three disorders were characterized by flow cytometry analysis, and the clonality of the T-cell large granular lymphocytic leukemia was confirmed by polymerase chain reaction. Interestingly, the patient has different B-cell clones, given that plasma cells of monoclonal gammopathy of unknown significance exhibited a kappa light-chain restriction population and, on the other hand, B-lymphocytes of monoclonal B-cell lymphocytosis exhibited a lambda light-chain restriction population. This finding does not support the antigen-driven hypothesis for the development of multi-compartment diseases, but suggests that T-cell large granular lymphocytic expansion might represent a direct antitumor immunological response to both B-cell and plasma-cell aberrant populations, as part of the immune surveillance against malignant neoplasms.

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Multidisciplinary benthic studies are still hindered by the lack of a unique fixative that satisfactorily preserves morphology and DNA, and that is simultaneously adequate for ecological surveys. The objective of this study is to test the performance of five fixatives: formalin, ethanol, dimethylsulfoxide with EDTA and NaCl salts (DESS), methanol with acetic acid (METHAC), and ethanol with acetic acid (ETHAC), for the preservation of estuarine and exclusively marine nematode assemblages for morphological, molecular, and ecological studies. The presence of the stain rose bengal in each fixative was also evaluated in the yield of PCR reactions. For molecular analyses, one species of each habitat was considered. Results revealed that fixative performance for morphological studies is habitat-and species-dependent. For studies of estuarine sediment nematodes, we recommend the use of pure ethanol, because it caused little morphological distortion (<10% of the assemblage), preserved all the species for ecological studies, and yielded high quality DNA sequences. For studies of exclusively marine environments, METHAC or DESS are the most adequate. The first performed better for morphological and ecological surveys, whereas the second was more appropriate for molecular research. For ecological studies, DESS should be used in comparison with formalin, in order to cross check the results. Finally, staining of samples with rose bengal is not recommended, because it hindered DNA amplification regardless of the fixative used.

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Susceptibility to acute lymphoblastic leukemia can be highly influenced by genetic polymorphisms in metabolizing enzyme genes of environmental carcinogens. This study aimed to evaluate the impact of the CYP3A5 and NAT2 metabolizing enzyme polymorphisms on the risk of childhood acute lymphoblastic leukemia. The analysis was conducted on 204 ALL patients and in 364 controls from a Brazilian population, using PCR-RFLP. The CYP3A5*3 polymorphic homozygous genotype was more frequent among ALL patients and the *3 allele variant was significantly associated with increased risk of childhood ALL (OR = 0.29; 95% CI, 0.14-0.60). The homozygous polymorphic genotype for the *6 allele variant was extremely rare and found in only two individuals. The heterozygous frequencies were similar for the ALL group and the control group. No significant differences were observed between the groups analyzed regarding NAT2 variant polymorphisms. None of the polymorphisms analyzed was related to treatment outcome. The results suggest that CYP3A5*3 polymorphism may play an important role in the risk of childhood ALL.

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Migraine is a complex neurological disorder with a clear neurogenic inflammatory component apparently including enhanced nitric oxide (NO) formation. Excessive NO amounts possibly contributing to migraine are derived from increased expression and activity of inducible NO synthase (iNOS). We tested the hypothesis that two functional, clinically relevant iNOS genetic polymorphisms (C-1026 A-rs2779249 and G2087A-rs2297518) are associated with migraine with or without aura. We studied 142 healthy women without migraine (control group) and 200 women with migraine divided into two groups: 148 with migraine without aura (MWA) and 52 with aura (MA). Genotypes were determined by real-time polymerase chain reaction using the Taqman (R) allele discrimination assays. The PHASE 2.1 software was used to estimate the haplotypes. The A allele for the G2087A polymorphism was more commonly found in the MA group than in the MWA group (28 vs. 18%; P < 0.05). No other significant differences in the alleles or genotypes distributions were found (P > 0.05). The haplotype combining both A alleles for the two polymorphisms was more commonly found in the MA group than in the control group or in the MWA group (19 vs. 10 or 8%; P = 0.0245 or 0.0027, respectively). Our findings indicate that the G2087A and the C-1026 A polymorphism in the iNOS gene affect the susceptibility to migraine with aura when their effects are combined within haplotypes, whereas the G2087A affects the susceptibility to aura in migraine patients. These finding may have therapeutic implications when examining the effects of selective iNOS inhibitors.

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SET protein (I2PP2A) is an inhibitor of PP2A, which regulates the phosphorylated Akt (protein kinase B) levels. We assessed the effects of SET overexpression in HEK293T cells, both in the presence and the absence of mild oxidative stress induced by 50 mu M tert-butyl hydroperoxide. Immunoblotting assays demonstrated that SET accumulated in HEK293T cells and increased the levels of phosphorylated Akt and PTEN; in addition, SET decreased glutathione antioxidant defense of cell and increased expression of genes encoding antioxidant defense proteins. Immunofluorescence analysis demonstrated that accumulated SET was equally distributed in cytoplasm and nucleus; however, in cells that had been exposed to oxidative stress, SET was found in large aggregates in the cytoplasm. SET accumulation in HEK293T cells correlated with inhibition of basal apoptosis as evidenced by a decrease in annexin V staining and activity of caspases; under mild oxidative stress, SET accumulation correlated with caspase-independent cell death, as evidenced by increased PI and annexin V/PI double staining. The results suggest that accumulated SET could act via Akt/PTEN either as cell survival signal or as oxidative stress sensor for cell death.

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Deficient formation of endogenous nitric oxide (NO) contributes to cardiovascular diseases, and this may be associated with increased circulating levels of matrix metalloproteinase-9 (MMP-9), as previously shown in white subjects. Because interethnic differences exist with respect to risk factors, prevalence, and severity of cardiovascular diseases, we designed this study to examine whether the circulating levels of nitrites (a marker of endogenous NO formation) are associated with the plasma levels of MMP-9 and MMP-2 in healthy black subjects. We studied 198 healthy subjects self-reported as blacks not taking any medications. Venous blood samples were collected and plasma and whole blood nitrite levels were measured using an ozone-based chemiluminescence assay. Plasma MMP-2 and MMP-9 levels were determined by gelatin zymography. We found a positive correlation between plasma MMP-9 and MMP-2 levels (P < 0.0001, rs = 0.556). Interestingly, we found a negative relationship between the plasma MMP-9 levels and the plasma or whole blood nitrites levels (P = 0.04, rs = -0.149; and P < 0.0001, rs = -0.349, respectively). In parallel, we found similar negative relationships between plasma MMP-2 levels and plasma or whole blood nitrites levels (P = 0.02, rs = -0.172; and P < 0.0001, rs = -0.454, respectively). This is the first study to show that endogenous nitric oxide formation correlates negatively with the circulating levels of both MMP-2 and MMP-9 in black subjects. Our findings suggest a mechanistic link between deficient NO formation and increased MMPs levels, which may promote cardiovascular diseases.

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Iodine is a critical element involved in thyroid hormone synthesis. Its efflux into the follicular lumen is thought to occur, in part, through pendrin at the apical membrane of thyrocytes. This study attempted to investigate whether iodide administration affects SLC26A4 mRNA expression in rat thyroid and in PCCl3 cells. Rats and cells were treated or not with Nal from 30 min up to 48 h. One group was concomitantly treated with sodium perchlorate. SLC26A4 mRNA expression was also investigated in PCCl3 cells treated with actinomycin D prior to Nal treatment. Iodide administration significantly increased SLC26A4 mRNA content in both models. The simultaneous administration of Nal and perchlorate, as well as the treatment of PCCl3 cells with actinomycin D prevented this effect, indicating that intracellular iodide is essential for this event, which appears to be triggered by transcriptional mechanisms. These data show that intracellular iodide rapidly upregulates SLC26A4 mRNA expression. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

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Surveys were conducted in Brazil, Benin and Tanzania to collect predatory mites as candidates for control of the coconut mite Aceria guerreronis Keifer, a serious pest of coconut fruits. At all locations surveyed, one of the most dominant predators on infested coconut fruits was identified as Neoseiulus baraki Athias-Henriot, based on morphological similarity with regard to taxonomically relevant characters. However, scrutiny of our own and published descriptions suggests that consistent morphological differences may exist between the Benin population and those from the other geographic origins. In this study, we combined three methods to assess whether these populations belong to one species or a few distinct, yet closely related species. First, multivariate analysis of 32 morphological characters showed that the Benin population differed from the other three populations. Second, DNA sequence analysis based on the mitochondrial cytochrome oxidase subunit I (COI) showed the same difference between these populations. Third, cross-breeding between populations was unsuccessful in all combinations. These data provide evidence for the existence of cryptic species. Subsequent morphological research showed that the Benin population can be distinguished from the others by a new character (not included in the multivariate analysis), viz. the number of teeth on the fixed digit of the female chelicera.