997 resultados para Isolated papillary muscles
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The in vitro activity of the crude hydroalcoholic extract of the aerial parts of Miconia langsdorffii Cogn. was evaluated against the promastigote forms of L. amazonensis, the causative agent of cutaneous leishmaniasis in humans. The bioassay-guided fractionation of this extract led to identification of the triterpenes ursolic acid and oleanolic acid as the major compounds in the fraction that displayed the highest activity. Several ursolic acid semi-synthetic derivatives were prepared, to find out whether more active compounds could be obtained. Among these ursolic acid-derived substances, the C-28 methyl ester derivative exhibited the best antileishmanial activity.
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We analyze the scanning tunneling microscopy (STM) signatures for the O/Cu(3)Au(100) surface from the low-coverage (isolated impurity) to high-coverage (oxide) regimes. First-principles calculations show that oxygen signatures switch from dark to bright spots as the oxygen coverage increases. This behavior is nicely traced back to a change in the oxygen orbital character of the Fermi-level electronic states. Our results allow for the chemical identification by STM of oxygen and copper atoms in the fully ordered O/Cu(3)Au(100)-c(2x2) surface.
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Background: The vascular endothelial growth factor (VEGF) is a major promoter of endothelial growth and migration. Some studies have shown a correlation between expression of this growth factor and prognosis in several cancers, including well-differentiated thyroid cancer. Aim: We studied VEGF expression, local invasiveness, and other prognostic factors in papillary thyroid carcinoma (PTC) to test the hypothesis that the expression of VEGF is correlated with the degree of invasion of PTC. Patients and Methods: Clinical and pathological data of 76 patients with PTC were retrospectively reviewed. Group 1 consisted of patients with gross locally invasive tumors, group 2 consisted of patients with only invasion of the thyroid capsule, and group 3 consisted of patients with noninvasive PTC. Results: VEGF expression was noted within the tumor in all groups of PTC patients but was absent in the surrounding normal tissue. Older patients had higher expression of VEGF than younger patients. The age of patients with strong reaction to VEGF was 46 +/- 14 (mean +/- standard deviation), and that in patients with a weaker reaction was 39 +/- 16 (p<0.05). Only 20% of patients with a follicular variant of PTC had a strong reaction to VEGF compared with 68% of patients with classical PTC (p<0.01). Conclusions: VEGF expression appears to be an early event in the development of PTC. Whether VEGF expression promotes the progression of PTC is not known, but the answer to this question may be important in view of its greater expression in older patients, a group whose prognosis in PTC is worse.
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Introduction: The purpose of this study was to compare the electromyography index of muscle coactivation of the following muscle pairs: posterior deltoid and pectoralis major (PD/PM); triceps brachii and biceps brachii (TB/BB); and serratus anterior and upper trapezius (SA/UT) during three different closed kinetic chain exercises (wall-press, bench-press and push-up) on an unstable surface at the maximal load. Methods: A total of 20 healthy sedentary men participated in the study. Integral linear values were obtained from three sustained contractions of six seconds each for the three proposed exercises. Mean coactivation index values were compared using the mixed-effects linear model, with a five percent significance level. Results: Electromyography indexes of muscle coactivation showed significant differences for the PD/PM and TB/BB muscle pairs. No differences were found between exercises for the SA/UT muscle pair. Conclusion: Our results seem to differ from those of previous studies, which reported that the similarity in exercises performed is responsible for the comparable muscle activation levels.
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We analyzed lesser diameter and distribution of fiber types in different skeletal muscles from female Wistar rats using a histoenzymology Myofibrillar Adenosine Tri-phosphatase (mATPase) method. Fragments from muscles were frozen and processed by mATPase in different pH. Adult and weanling rat soleus muscles presented a predominance of type I fibers and larger fiber diameters. In the plantar muscle in adult rats, the type IIB fibers demonstrated greater lesser diameter while in the weanling animals, types I and IIB fibers were larger. The plantar muscle of animals of both ages was composed predominantly of the type IID fibers. The type IID fibers were observed in similar amounts in the lateral gastrocnemius and the medial gastrocnemius muscles. Type IIB fibers showed predominance and presented higher size in comparison with other types in the EDL muscle. The present study shows that data on fiber type distribution and fiber lesser diameter obtained in adult animals cannot always be applied to weanling animals of the same species. Using the mATPase, despite the difficult handling, is an important tool to determine the different characteristics of the specific fibers in the skeletal muscle tissue.
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The complete genome sequences of two Brazilian wild-type rabies viruses (RABV), a BR-DR1 isolate from a haematophagous bat (Desmodus rotundus) and a BR-AL1 isolate from a frugivorous bat (Artibeus lituratus), were determined. The genomes of the BR-DR1 and RR-AL1 had 11,923 and 11,922 nt, respectively, and both encoded the five standard genes of rhabdoviruses. The complete nucleotide sequence identity between the BR-DR1 and BR-AL1 isolates was 97%. The BR-DR1 and BR-AL1 isolates had some conserved functional sites revealed by the fixed isolates, whereas both isolates had unique amino acid substitutions in the antigenic region IV of the nucleocapsid gene. Therefore, it is speculated that both isolates were nearly identical in virologic character. According to our phylogenetic analysis based on the complete genomes, both isolates belonged to genotype 1, and to the previously defined ""vampire bat-related RABV lineage"" which consisted of mainly D. rotundus- and A. lituratus- isolates; however, a branch pattern with high bootstrap values suggested that BR-DR1 was more closely related to the 9001FRA isolate, which was collected from a dog bitten by a bat in French Guiana, than to BR-AL1. This result suggests that the vampire bat-related RABV lineage includes Brazilian vampire bat and Brazilian frugivorous bat RABV and is further divided into Brazilian vampire bat and Brazilian frugivorous bat RABV sub-lineages. The phylogenetic analysis based on the complete genomes was valuable in discriminating among very closely related isolates.
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The relatively large number of nearby radio-quiet and thermally emitting isolated neutron stars (INSs) discovered in the ROSAT All-Sky Survey, dubbed the ""Magnificent Seven"", suggests that they belong to a formerly neglected major component of the overall INS population. So far, attempts to discover similar INSs beyond the solar vicinity failed to confirm any reliable candidate. The good positional accuracy and soft X-ray sensitivity of the EPIC cameras onboard the XMM-Newton satellite allow us to efficiently search for new thermally emitting INSs. We used the 2XMMp catalogue to select sources with no catalogued candidate counterparts and with X-ray spectra similar to those of the Magnificent Seven, but seen at greater distances and thus undergoing higher interstellar absorptions. Identifications in more than 170 astronomical catalogues and visual screening allowed us to select fewer than 30 good INS candidates. In order to rule out alternative identifications, we obtained deep ESO-VLT and SOAR optical imaging for the X-ray brightest candidates. We report here on the optical follow-up results of our search and discuss the possible nature of 8 of our candidates. A high X-ray-to-optical flux ratio together with a stable flux and soft X-ray spectrum make the brightest source of our sample, 2XMM J104608.7-594306, a newly discovered thermally emitting INS. The X-ray source 2XMM J010642.3+005032 has no evident optical counterpart and should be further investigated. The remaining X-ray sources are most probably identified with cataclysmic variables and active galactic nuclei, as inferred from the colours and flux ratios of their likely optical counterparts. Beyond the finding of new thermally emitting INSs, our study aims at constraining the space density of this Galactic population at great distances and at determining whether their apparently high density is a local anomaly or not.
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Over the last decade, X-ray observations have revealed the existence of several classes of isolated neutron stars (INSs) which are radio-quiet or exhibit radio emission with properties much at variance with those of ordinary radio pulsars. The identification of new sources is crucial in order to understand the relations among the different classes and to compare observational constraints with theoretical expectations. A recent analysis of the 2XMMp catalogue provided fewer than 30 new thermally emitting INS candidates. Among these, the source 2XMM J104608.7-594306 appears particularly interesting because of the softness of its X-ray spectrum, kT = 117 +/- 14 eV and N(H) = (3.5 +/- 1.1) x 10(21) cm(-2) (3 sigma), and of the present upper limits in the optical, m(B) greater than or similar to 26, m(V) greater than or similar to 25.5 and m(R) greater than or similar to 25 (98.76% confidence level), which imply a logarithmic X-ray-to-optical flux ratio log(F(X)/F(V)) greater than or similar to 3.1, corrected for absorption. We present the X-ray and optical properties of 2XMM J104608.7-594306 and discuss its nature in the light of two possible scenarios invoked to explain the X-ray thermal emission from INSs: the release of residual heat in a cooling neutron star, as in the seven radio-quiet ROSAT-discovered INSs, and accretion from the interstellar medium. We find that the present observational picture of 2XMM J104608.7-594306 is consistent with a distant cooling INS with properties in agreement with the most up-to-date expectations of population synthesis models: it is fainter, hotter and more absorbed than the seven ROSAT sources and possibly located in the Carina Nebula, a region likely to harbour unidentified cooling neutron stars. The accretion scenario, although not entirely ruled out by observations, would require a very slow (similar to 10 km s(-1)) INS accreting at the Bondi-Hoyle rate.
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The remarkable astrometric capabilities of the Chandra Observatory offer the possibility to measure proper motions of X-ray sources with an unprecedented accuracy in this wavelength range. We recently completed a proper motion survey of three of the seven thermally emitting radio-quiet isolated neutron stars (INSs) discovered in the ROSAT all-sky survey. These INSs (RXJ0420.0-5022, RXJ0806.4-4123 and RXJ1308.6+2127) either lack an optical counterpart or have one so faint that ground based or space born optical observations push the current possibilities of the instrumentation to the limit. Pairs of ACIS observations were acquired 3 to 5 years apart to measure the displacement of the sources on the X-ray sky using as a reference the background of extragalactic or remote Galactic X-ray sources. We derive 2 sigma upper limits of 123 mas yr(-1) and 86 mas yr(-1) on the proper motion of RXJ0420.0-5022 and RXJ0806.4-4123, respectively. RXJ1308.6+2127 exhibits a very significant displacement (similar to 9 sigma) yielding mu = 220 +/- 25 mas yr(-1), the second fastest measured among all ROSAT-discovered INSs. The source is probably moving away rapidly from the Galactic plane at a speed which precludes any significant accretion of matter from the interstellar medium. Its transverse velocity of similar to 740 (d/700 pc) km s(-1) might be the largest of all ROSAT INSs and its corresponding spatial velocity lies among the fastest recorded for neutron stars. RXJ1308.6+2127 is thus a middle-aged (age similar to 1 My) high velocity cooling neutron star. We investigate its possible origin in nearby OB associations or from a field OB star. In most cases, the flight time from birth place appears significantly shorter than the characteristic age derived from spin down rate. Overall, the distribution in transverse velocity of the ROSAT INSs is not statistically different from that of normal radio pulsars.
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Correlations of charged hadrons of 1< p(T) < 10 Gev/c with high pT direct photons and pi(0) mesons in the range 5< p(T) < 15 Gev/c are used to study jet fragmentation in the gamma + jet and dijet channels, respectively. The magnitude of the partonic transverse momentum, k(T), is obtained by comparing to a model incorporating a Gaussian kT smearing. The sensitivity of the associated charged hadron spectra to the underlying fragmentation function is tested and the data are compared to calculations using recent global fit results. The shape of the direct photon-associated hadron spectrum as well as its charge asymmetry are found to be consistent with a sample dominated by quark-gluon Compton scattering. No significant evidence of fragmentation photon correlated production is observed within experimental uncertainties.
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While evaluating several laboratory-cultured cyanobacteria strains for the presence of paralytic shellfish poison neurotoxins, the hydrophilic extract of Microcystis aeruginosa strain SPC777-isolated from Billings`s reservoir, So Paulo, Brazil-was found to exhibit lethal neurotoxic effect in mouse bioassay. The in vivo test showed symptoms that unambiguously were those produced by PSP. In order to identify the presence of neurotoxins, cells were lyophilized, and the extracts were analyzed by HPLC-FLD and HPLC-MS. HPLC-FLD analysis revealed four main Gonyautoxins: GTX4(47.6%), GTX2(29.5%), GTX1(21.9%), and GTX3(1.0%). HPLC-MS analysis, on other hand, confirmed both epimers, with positive Zwitterions M(+) 395.9 m/z for GTX3/GTX2 and M(+) 411 m/z for GTX4/GTX1 epimers. The hepatotoxins (Microcystins) were also evaluated by ELISA and HPLC-MS analyses. Positive immunoreaction was observed by ELISA assay. Alongside, the HPLC-MS analyses revealed the presence of [l-ser(7)] MCYST-RR. The N-methyltransferase (NMT) domain of the microcystin synthetase gene mcyA was chosen as the target sequence to detect the presence of the mcy gene cluster. PCR amplification of the NMT domain, using the genomic DNA of the SPC777 strain and the MSF/MSR primer set, resulted in the expected 1,369 bp product. The phylogenetic analyses grouped the NMT sequence with the NMT sequences of other known Microcystis with high bootstrap support. The taxonomical position of M. aeruginosa SPC777 was confirmed by a detailed morphological description and a phylogenetic analysis of 16S rRNA gene sequence. Therefore, co-production of PSP neurotoxins and microcystins by an isolated M. aeruginosa strain is hereby reported for the first time.
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The ability of a recently isolated Scheffersomyces stipitis strain (UFMG-IMH 43.2) to produce ethanol from xylose was evaluated. For the assays, a hemicellulosic hydrolysate produced by dilute acid hydrolysis of sugarcane bagasse was used as the fermentation medium. Initially, the necessity of adding nutrients (MgSO(4).7H(2)O, yeast extract and/or urea) to this medium was verified, and the yeast extract supplementation favoured ethanol production by the yeast. Then, in a second stage, assays under different initial xylose and cell concentrations, supplemented or not with yeast extract, were performed. All these three variables showed significant (p < 0.05) influence on ethanol production. The best results (ethanol yield and productivity of 0.19 g/g and 0.13 g/l/h, respectively) were obtained using the hydrolysate containing an initial xylose concentration of 30 g/l, supplemented with 5.0 g/l yeast extract and inoculated with an initial cell concentration of 2.0 g/l. S. stipitis UFMG-IMH 43.2 was demonstrated to be a yeast strain with potential for use in xylose conversion to ethanol. The establishment of the best fermentation conditions was also proved to be of great importance to increasing the product formation by this yeast strain. These findings open up new perspectives for the establishment of a feasible technology for ethanol production from hemicellulosic hydrolysates. Copyright (C) 2011 John Wiley & Sons, Ltd.
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Amylases and lipases are highly demanded industrial enzymes in various sectors such as food, pharmaceuticals, textiles, and detergents. Amylases are of ubiquitous occurrence and hold the maximum market share of enzyme sales. Lipases are the most versatile biocatalyst and bring about a range of bioconversion reactions such as hydrolysis, inter-esterification, esterification, alcoholysis, acidolysis, and aminolysis. The objective of this work was to study the feasibility for amylolitic and lipolytic production using a bacterium strain isolated from petroleum contaminated soil in the same submerged fermentation. This was a sequential process based on starch and vegetable oils feedstocks. Run were performed in batchwise using 2% starch supplemented with suitable nutrients and different vegetable oils as a lipase inducers. Fermentation conditions were pH 5.0; 30 degrees C, and stirred speed (200 rpm). Maxima activities for amyloglucosidase and lipase were, respectively, 0.18 and 1,150 U/ml. These results showed a promising methodology to obtain both enzymes using industrial waste resources containing vegetable oils.
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Study design: Controlled clinical test. Objectives: The purpose of this study was to assess the effects of quadriceps and anterior tibial muscles electrical stimulation on the feet and ankles of patients with spinal cord injuries and to compare them with able-bodied individuals and a group of patients who did not undergo neuromuscular electrical stimulation (NMES). Setting: This study was conducted at the Hospital das Clinicas of Unicamp, Campinas, Sao Paulo, Brazil. Methods: Between January and April 2008, 30 patients at the spinal cord injury ambulatory clinic who underwent NMES (group A) were submitted to a clinical and radiographic assessment of their feet and ankles and compared with a spinal cord injury group (group B) who did not undergo NMES and a group of able-bodied individuals (group C). The Kruskal-Wallis test was used to compare all the three groups, and between-group differences (P < 0.05) were investigated with the Mann-Whitney test. Results: The mean mobility of the midfoot and ankle subtalar joint was significantly higher in group C than in groups A and B. Differences in the mean measurements of the profiles of the talocalcaneal and the talus-first metatarsal angles were statistically significant for group A vs the other groups (P = 0.0020, 0.0024, respectively). Foot deformities were found in groups including claw toes and flat feet (group A) and grade I ulcers on the lateral malleolus and calcaneus (group B). Conclusion: Partial-load NMES maintains the feet and ankles in a planted and adequate walking position in patients with spinal cord injuries, a favorable result of new technologies that allows these patients to reacquire independent walking capacity. Spinal Cord (2010) 48, 881-885; doi:10.1038/sc.2010.50; published online 18 May 2010
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Objectives: To study the effect of additional strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise rehabilitation programme for patients with the patellofemoral pain syndrome. Design: Randomized controlled pilot trial. Setting: Clinical setting with home programme. Participants: Fourteen patients with patellofemoral pain syndrome. Intervention: The subjects were randomly assigned to the intervention group (strengthening of quadriceps plus strengthening of hip abductor and lateral rotator muscles) or to the control group (strengthening of quadriceps). Both groups participated in a six-week home exercise protocol. Main outcome measures: The perceived pain symptoms, isokinetic eccentric knee extensor, hip abductor and lateral rotator torques and the gluteus medius electromyographic activity were assessed before and after treatment. Parametric and non-parametric tests were used to compare the groups before and after treatment with alpha = 0.05. Results: Only the intervention group improved perceived pain symptoms during functional activities (P=0.02-0.04) and also increased their gluteus medius electromyographic activity during isometric voluntary contraction (P=0.03), Eccentric knee extensors torque increased in both groups (P=0.04 and P=0.02). There was no statistically significant difference in the hip muscles torque in either group. Conclusion: Supplementation of strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise programme provided additional benefits with respect to the perceived pain symptoms during functional activities in patients with patellofemoral pain syndrome after six weeks of treatment.