46 resultados para Changing Permafrost in the Arctic and its Global Effects in the 21st Century


Relevância:

100.00% 100.00%

Publicador:

Resumo:

A method for the simultaneous analysis of the enantiomers of mefloquine (MQ) and its main metabolite carboxymefloquine (CMQ) in plasma is described for the first time. The assay involves two-step liquid-phase micro-extraction (LPME) and enantioselective high-performance liquid chromatography. In the first LPME step, the enantiomers of MQ were extracted from an alkalinized sample through a thin layer of di-n-hexyl ether immobilized in the pores of the hollow fiber and into 0.01 M perchloric acid as acceptor solution. In the second LPME step, the same sample was acidified to enable the extraction of CMQ using the same organic solvent and 0.05 M sodium hydroxide as acceptor phase. The analytes were resolved on a Chirobiotic T column in the polar-organic mode of elution and detected at 285 nm. The recovery rates from 1 mL of plasma were in the range 35-38%. The method presented limits of quantification of 50 ng/mL for all analytes and was linear up to 1,500 and 3,000 ng/mL for the enantiomers of MQ and CMQ, respectively. The plasmatic concentrations of (+)-(RS)-MQ were higher than those of (-)-(SR)-MQ after oral administration of the racemic drug to rats.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Proteins incorporated into phospholipid Langmuir-Blodgett (LB) films are a good model system for biomembranes and enzyme immobilization studies. The specific fluidity of biomembranes, an important requisite for enzymatic activity, is naturally controlled by varying phospholipid compositions. In a model system, instead, LB film fluidity may be varied by covering the top layer with different substances able to interact simultaneously with the phospholipid and the protein to be immobilized. In this study, we immobilized a carbohydrate rich Neurospora crassa alkaline phosphatase (NCAP) in monolayers of the sodium salt of dihexadecylphosphoric acid (DHP), a synthetic phospholipid that provides very condensed Langmuir films. The binding of NCAP to DHP Langmuir-Blodgett (LB) films was mediated by the anionic polysaccharide iota-carrageenan (iota-car). Combining results from surface isotherms and the quartz crystal microbalance technique, we concluded that the polysaccharide was essential to promote the interaction between DHP and NCAP and also to increase the fluidity of the film. An estimate of DHP:iota-car ratio within the film also revealed that the polysaccharide binds to DHP LB film in an extended conformation. Furthermore, the investigation of the polysaccharide conformation at molecular level, using sum-frequency vibrational spectroscopy (SFG), indicated a preferential conformation of the carrageenan molecules with the sulfate groups oriented toward the phospholipid monolayer, and both the hydroxyl and ether groups interacting preferentially with the protein. These results demonstrate how interfacial electric fields can reorient and induce conformational changes in macromolecules, which may significantly affect intermolecular interactions at interfaces. This detailed knowledge of the interaction mechanism between the enzyme and the LB film is relevant to design strategies for enzyme immobilization when orientation and fluidity properties of the film provided by the matrix are important to improve enzymatic activity.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The metabolic syndrome (MetS) is associated with increased cardiovascular morbidity and mortality. Intermittent claudication reflects the presence of peripheral arterial disease (PAD). The aim of this study is to determine the prevalence of the MetS in claudicants and its correlation with age, gender, localization of arterial obstruction, and symptomatic coronary disease. Patients (n = 170) with intermittent claudication were studied. The mean age was 65 years (33-89). Metabolic syndrome was diagnosed in 98 patients (57.6%). The mean age of patients with MetS was 63.5 years compared with 67.0 years for patients without MetS (P = .027). Considering patients aged >= 65 years, MetS was present in 46 (48.9%) individuals and in 52 (68.4%) patients younger than 65 years (P = .011). Metabolic syndrome must be actively searched for in claudicant patients.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: Refractory gastroesophageal reflux disease (GERD) can be related to greater sensitization to foods. Objective: To evaluate sensitization to foods in patients with refractory GERD. Methods: Patients with refractory GERD after using at least 40 mg of a proton pump inhibitor were given a restriction diet based on the results of skin prick testing and atopy patch testing with foods. The characteristics of sensitized patients were compared with those of nonsensitized patients in relation to atopy and number of eosinophils in the esophageal mucosa. Results: The prevalence of sensitization to foods was 27.7%. Asthmatic patients showed higher sensitization to foods (P = .008). Eosinophils were determined to be present in the esophageal mucosa in 15.8% of patients, and this correlated with greater sensitization to foods (P = .01). One case of eosinophilic esophagitis was confirmed. A diet excluding identified sensitizing foods led to clinical improvement regarding GERD symptoms (P = .004). Conclusion: The presence of eosinophils in esophageal mucosa associated with greater sensitization to foods and the response to a restriction diet in patients with positive test results suggest that refractory GERD can represent an initial stage of eosinophilic esophagitis. Ann Allergy Asthma Immunol. 2010;105:359-363.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The present study aimed to investigate the presence of corpus callosum (CC) volume deficits in a population-based recent-onset psychosis (ROP) sample, and whether CC volume relates to interhemispheric communication deficits. For this purpose, we used voxel-based morphometry comparisons of magnetic resonance imaging data between ROP (n = 122) and healthy control (n = 94) subjects. Subgroups (38 ROP and 39 controls) were investigated for correlations between CC volumes and performance on the Crossed Finger Localization Test (CFLT). Significant CC volume reductions in ROP subjects versus controls emerged after excluding substance misuse and non-right-handedness. CC reductions retained significance in the schizophrenia subgroup but not in affective psychoses subjects. There were significant positive correlations between CC volumes and CFLT scores in ROP subjects, specifically in subtasks involving interhemispheric communication. From these results, we can conclude that CC volume reductions are present in association with ROP. The relationship between such deficits and CFLT performance suggests that interhemispheric communication impairments are directly linked to CC abnormalities in ROP. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective: To analyze vascular density and immunolocalization of angiogenic vascular endothelial growth factor (VEGF) and its receptor Flk-1 in the proliferative and secretory eutopic human endometrium. and in three different sites of endometriosis: the ovary, bladder, and rectum. Design: Prospective study. Setting: University hospital. Patient(s): Thirty women with endometriosis (10 ovarian, 1.0 bladder, 10 rectal) and 32 control women (10 proliferative endometrium, 10 secretory endometrium, 4 normal ovary, 4 normal bladder, 4 normal rectum). Intervention(s): Normal endometrial samples were obtained from women during laparoscopic ablation of subserous myoma, and biopsy specimens of endometriosis were obtained from patients undergoing surgery for the diagnosis and treatment of endometriosis. Normal tissues of ovary, bladder, and rectum were obtained from these organs beside the lesions of endometriosis. Main Outcome Measure(S): Blood vessels were quantified according to the number of von Willebrand factor-positive endothelial cells. The VEGF and Flk-1 distribution were evaluated semiquantitatively by immunohistochemical staining. Result(s): More blood vessels were found in cases of endometriosis, particularly rectal endometriosis, compared with the respective control samples and with the eutopic endometrium, and they were localized in endometrial stroma around the glands. The VEGF and Flk-1 expression levels were also higher in cases of endometriosis, especially rectal endometriosis. Conclusion(s): Vascularization and VEGF and Flk-1 expression are significantly higher in deeply infiltrating endometriosis affecting the rectum, reinforcing the hypothesis that antiangiogenesis therapy may constitute a new modality of treatment, especially in cases of deep endometriosis involving the rectum.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The objective of the present study was to investigate the correlation between macrophage activity and apoptosis in the polar forms of leprosy because the immunopathological phenomena involved in these forms are still poorly understood For this purpose, 29 skin biopsy samples obtained from patients with the polar forms of leprosy were analyzed. Macrophage activity and apoptosis were evaluated by immunohistochemistry using lysozyme, CD68, iNOS and caspase 3 as markers The nonparametric Mann-Whitney test and Spearman`s linear correlation test were used for statistical analysis The results suggest that the apoptosis rate is under the direct influence of macrophage activity in lesions of patients with the tuberculoid form In contrast, in lepromatous lesions other factors seem to induce programmed cell death, possibly TGF-beta. Further studies are necessary to identify additional factors involved in the immunopathogenesis of leprosy. (C) 2010 Elsevier Ltd. All rights reserved

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This retrospective study analyzed the HLA-B*27 alleles in a group of 20 consecutive patients with the diagnosis of Reiter syndrome (RS) followed in a tertiary referral university hospital in Brazil, during the period 1990-2006, and compared the data with that observed in other patients with spondyloarthropathies followed at the same institution. Eight cases were associated to gastrointestinal infection, eight cases to previous urethritis, and four cases presented no established preceding infection. HLA-B*27 alleles were typed by polymerase chain reaction-amplified DNA hybridized with sequence-specific oligonucleotide probes (HLA-B*2701 to HLA-B*2721). They were compared to a group of 108 patients with ankylosing spondylitis (AS), 40 with undifferentiated spondyloarthropathy (uSpA) and 111 healthy controls. Among the 20 patients, 17 were HLA-B*27 positive (85%). Two HLA-B*27 alleles were observed: HLA-B*2705 (65%) and HLA-B*2702 (35%). In the other spondyloarthropathies, the observed alleles were HLA-B*2705 (90% in AS and 92.5% in uSpA), HLA-B*2702 (8% in AS and 5% in uSpA), HLA-B*2704 (1% in AS and 2.5% in uSpA) and HLA-B*2713 (1% in AS). Among the 111 healthy controls, 80% presented HLA-B*2705, followed by HLA-B*2702 in 10%, HLA-B*2703 in 6%, HLA-B*2707 in 3% and HLA-B*2713 in 1%. Concluding, in the HLA-B*27 positive patients with RS in this study there was predominance of HLA-B*2705 allele, in a lower frequency than that observed in patients with other spondyloarthropathies and healthy controls.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the present study, the participation of the Na(v)1.8 sodium channel was investigated in the development of the peripheral pro-nociceptive state induced by daily intraplantar injections of PGE(2) in rats and its regulation in vivo by protein kinase A (PKA) and protein kinase C epsilon (PKC epsilon) as well. In the prostaglandin E(2) (PGE(2))-induced persistent hypernociception, the Na(v)1.8 mRNA in the dorsal root ganglia (DRG) was up-regulated. The local treatment with dipyrone abolished this persistent hypernociception but did not alter the Na(v)1.8 mRNA level in the DRG. Daily intrathecal administrations of antisense Na(v)1.8 decreased the Na(v)1.8 mRNA in the DRG and reduced ongoing persistent hypernociception. once the persistent hypernociception had been abolished by dipyrone, but not by Na(v)1.8 antisense treatment, a small dose of PGE(2) restored the hypernociceptive plateau. These data show that, after a period of recurring inflammatory stimuli, an intense and prolonged nociceptive response is elicited by a minimum inflammatory stimulus and that this pro-nociceptive state depends on Na(v)1.8 mRNA up-regulation in the DRG. in addition, during the persistent hypernociceptive state, the PKA and PKC epsilon expression and activity in the DRG are up-regulated and the administration of the PKA and PKC epsilon inhibitors reduce the hypernociception as well as the Na(v)1.8 mRNA level. In the present study, we demonstrated that the functional regulation of the Na(v)1.8 mRNA by PKA and PKC epsilon in the primary sensory neuron is important for the development of the peripheral pro-nociceptive state induced by repetitive inflammatory stimuli and for the maintenance of the behavioral persistent hypernociception. (C) 2008 Elsevier Inc. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The aim of this study is to determine the concentrations of lidocaine and its metabolite, monoethylglycine xylidide (MEGX), and of the enantiomers of bupivacaine in maternal and fetal compartments. Ten healthy pregnant women were submitted to epidural anesthesia. Drug concentrations were determined in the maternal vein, fetal umbilical artery and vein, and the placental intervillous space. The highest concentrations of the bupivacaine enantiomers lidocaine and of lidocaine and of its MEGX metabolite were detected in maternal plasma and in the placental intervillous space. The placental transfer was 33% for the (+)-(R)-bupivacaine enantiomer and 31% for the (-)-(S)-bupivacaine enantiomer. For lidocaine and its MEGX metabolite, respective placental transfers were 60% and 43%. Lidocaine concentration in the fetal umbilical vein was 1.46 times higher than in the fetal umbilical artery. The highest concentrations of lidocaine and its metabolite and of the enantiomers of bupivacaine were detected in the placental intervillous space. The higher lidocaine concentrations in the fetal umbilical vein than in the fetal umbilical artery suggest that there was tissue uptake of the drug or drug metabolization by the fetus.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background. The live attenuated yellow fever (YF) vaccines have been available for decades and are considered highly effective and one of the safest vaccines worldwide. Methods. The impact of YF-17DD-antigens recall on cytokine profiles of YF-17DD-vaccinated children were characterized using short-term cultures of whole blood samples and single-cell flow cytometry. This study enrolled seroconverters and nonseroconverters after primovaccination (PV-PRNT(+) and PV-PRNT(-)), seroconverters after revaccination (RV-PRNT(+)), and unvaccinated volunteers (UV-PRNT(-)). Results. The analysis demonstrated in the PV-PRNT(+) group a balanced involvement of pro-inflammatory/regulatory adaptive immunity with a prominent participation of innate immunity pro-inflammatory events (IL-12(+) and TNF-alpha(+) NEU and MON). Using the PV-PRNT(+) cytokine signature as a reference profile, PV-PRNT(+) presented a striking lack of innate immunity proinflammatory response along with an increased adaptive regulatory profile (IL-4(+) CD4(+) T cells and IL-10(+) and IL-5(+) CD8(+) T cells). Conversely, the RV-PRNT(+) shifted the overall cytokine signatures toward an innate immunity pro-inflammatory profile and restored the adaptive regulatory response. Conclusions. The data demonstrated that the overall cytokine signature was associated with the levels of PRNT antibodies with a balanced innate/adaptive immunity with proinflammatory/regulatory profile as the hallmark of PV-PRNT(MEDIUM+), whereas a polarized regulatory response was observed in PV-PRNT(-) and a prominent proinflammatory signature was the characteristic of PV-PRNT(HIGH+).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

There is evidence that several fibroblast growth factors (FGFs) are involved in growth and development of the corpus luteum (CL), but many FGFs have not been investigated in this tissue, including FGF10. The objective of this study was to determine if FGF10 and its receptor (FGFR2B) are expressed in the CL. Bovine CL were collected from an abattoir and classed as corpus hemorrhagica (stage 1), developing (stage 11), developed (stage 111), and regressed (stage IV) CL. Expression of FGF10 and FGFR2B mRNA was measured by reverse transcription-polymerase chain reaction (RT-PCR). Both genes were expressed in bovine CL, and FGF10 expression did not differ between stages of CL development. FGF10 protein was localized to large and small luteal cells by immunohistochemistry. FGFR2B expression was approximately threefold higher in regressed compared to developing and developed CL (P < 0.05). To determine if FGF10 and FGFR2B expression is regulated during functional luteolysis, cattle were injected with PGF2 alpha and CL collected at 0, 0.5, 2, 4, 12, 24, 48, and 64 hr thereafter (n = 5 CL/time point), and mRNA abundance was measured by real-time RT-PCR. FGF10 mRNA expression did not change during functional luteolysis, whereas FGFR2B mRNA abundance decreased significantly at 2, 4, and 12 hr after PGF2a, and returned to pretreatment levels for the period 24-64 hr post-PGF2 alpha. These data suggest a potential role for FGFR2B signaling during structural luteolysis in bovine CL.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Serum samples were collected from 582 horses from 40 stud farms in the State of Sao Paulo and tick (Acari: Ixodidae) infestations were evaluated on them. Serum samples were subjected to the complement fixation test (CFT) and a competitive inhibition ELISA (cELISA) for Babesia caballi and Theileria equi. Logistic regression analyses were performed to construct multivariate models that could explain the dependent variable (horses positive for B. caballi or T equi) as a function of the independent variables (presence or abundance of each one of the rick species found on the farms). A higher overall prevalence of B. caballi (54.1%) than of T equi (21.6%) was found by the two tests. The ticks Dermacentor nitens Neumann, 1897, Amblyomma cajennense (Fabricius, 1787) and Rbipicephalus (Boopbilus) microplus (Canestrini, 1887) were present on horses on 38 (95%), 20 (50%), and 4 (10%) farms, respectively. Infestations by D. nitens were statistically associated with B. caballi-positive horses on the farms by either the CFT or cELISA. Infestations by A. cajennense were statistically associated with T equi-positive horses on the farms by either CFT or cELISA.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The progress of science in search of new techniques of the nerve regeneration and the functional repair in reinnervated muscle has been the target of many researchers around the world. Consequently, nerves and muscles in different body segments asked for more enlightenment of their morphology, their interrelation with other anatomic structures and their peculiarities. One of the most significant areas that need deeper studies is the region of the head and neck, since they are often affected by important pathologies. In order to offer the researcher`s community a morphological myoneural interaction model, this study elected the levator labii superioris muscle and its motor nerve, the buccal branch of the facial nerve (VII pair) not only for its special characteristics, but also its value on the facial expression. The rat was chosen for this investigation for being easy to obtain, to keep, to manipulate and to compare this experiment with many others studies previously published. The techniques used were Mesoscopic (dissection), histoenzymologic and morphometric ones. In the results the muscle proved to have a predominance of fast twich fibers (FG and FOG) and superficial location, with a proximal bone and a distal cutaneous insertion. Its motor nerve, the buccal branch of the facial nerve (VII pair), breaks through the muscle belly into its deep face, and comprised a heterogeneous group of myelinic nerve fibers disposed in a regular form in all fascicle. Near the motor point, the nerve showed to be composed of two fascicles with different sizes. Due to the small nerve dimensions, the nerve fibers have a smaller diameter if compared to the motor nerve of pectineus muscle of the cat. Further studies with neural tracers have already had a start in order to provide more information about the distribution and the architecture of these fibers.