953 resultados para Nucleophilic attack


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Neuromyelitis optica has not been thoroughly studied in Brazilian patients following the discovery of NMO-IgG and its specific antigen aquaporin-4. In this study we aimed to describe the clinical NMO-IgG immunological status and neuroimaging characteristics of recurrent neuromyelitis optica in a series Brazilian patients. We undertook a retrospective study of 28 patients with recurrent neuromyelitis optica, according to 1999 Wingerchuk`s diagnostic criteria. Data on NMO-IgG status, clinical features, and MRI findings were analyzed. Three men and 25 women were evaluated. Median age at onset of disease was 26 years (range 7-55); median time of follow-up was 7 years (range 2-14). The mean time elapsed between the first and the second attack was 17 months (median 8.5; range 2-88). NMO-IgG was detected in 18 patients (64.3%). Four patients died due to respiratory failure. Most patients presented with cervical (36%) and cervical-thoracic myelitis (46.4%). Holocord lesion was the most common pattern of involvement (50%) on the axial plane. We did not find a statistical association between myelitis extension and NMO-IgG result. Our series of Brazilian patients showed a younger age of onset than previously reported. In our series, in contrast to previous reports, there was no correlation between the extension of myelitis and NMO-IgG positivity.

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Experiments were performed to investigate senses that are essential for mediating fright reaction and food behavior in Pseudoplatystoma corruscans, pintado. The dilemma ""to feed or to flee"" was also analyzed in fishes with intact and sectioned olfactory tracts, stimulated by alarm substance extracts and food. Fishes were arranged into five groups: fish with intact lateral olfactory tracts (LOT), fish with intact medial olfactory tract (MOT), fish with tracts totally sectioned (TOTAL, both LOT and MOT), sham operated, and nonoperated fish. The five groups were submitted to either alarm substance extract and food stimulus or to distilled water (control) and food stimulus. Fish reacted to food independently of which tract (LOT, MOT or TOTAL) was sectioned; vision seems necessary and elemental to detect and deflagrate food response. Latency of the responses to each reaction was different between groups. None of the fish with sectioned tracts reacted to alarm substance extract, while sham- and nonoperated fish showed the typical alarm behavior response, leading to the conclusion that olfaction is essential for mediating alarm response. These results indicate that others sense systems (e.g., vision) are sufficient to trigger and elicit feeding behavior and that olfaction is not necessary to fully maintain food detection to qualitative and quantitative extent. However, olfactory tract integrity seems to be required for mediation of alarm reaction in P. corruscans.

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Background: Prevalence and clinical correlates of depersonalization symptoms have been associated with panic disorder. Personality traits might increase the likelihood of experiencing depersonalization symptoms or depersonalization disorder in panic patients. Aims: The objectives of this study are to establish the prevalence of depersonalization symptoms during the panic attack and in depersonalization disorder and to examine the personality factors associated with the presence of depersonalization in patients with panic disorder. Methods: The sample comprised 104 consecutive adult outpatients with panic disorder, diagnosed according to the Semistructured Clinical Interview for DSM-IV (Axis I/II disorders). Participants were assessed with the Cambridge Depersonalization Scales, the Temperament and Character Inventory, and the Panic and Agoraphobia Scale. Results: Forty-eight percent of the sample had depersonalization symptoms during the panic attack, whereas 20% of patients had a depersonalization disorder. Women presented more depersonalization disorders than did men (P = .036). Patients with panic disorder with depersonalization disorder had a more severe panic disorder (P = .002). Logistic regression analysis showed that self-transcendence trait (odds ratio, 1.089; 95% confidence interval, 1.021-1.162; P = .010) and severity of panic (odds ratio, 1.056; 95% confidence interval, 1.005-1.110; P = .032) were independently associated with depersonalization disorder. Conclusions: A high prevalence of depersonalization symptoms and depersonalization disorder was confirmed in patients with panic disorder, supporting a dosage effect model for understanding depersonalization pathology. Self-transcendence trait and severity of panic disorder were reported as risk factors for depersonalization disorder. (C) 2011 Elsevier Inc. All rights reserved.

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Evidence from animal models of anxiety has led to the hypothesis that serotonin enhances inhibitory avoidance (related to anxiety) in the forebrain, but inhibits one-way escape (panic) in the midbrain periaqueductal gray (PAG). Stressing the difference between these emotions, neuroendocrinological results indicate that the hypothalamic-pituitary-adrenal axis is activated by anticipatory anxiety, but not by panic attack nor by electrical stimulation of the rat PAG. Functional neuroimaging has shown activation of the insula and upper brain stem (including PAG), as well as deactivation of the anterior cingulated cortex (ACC) during experimental panic attacks. Voxel-based morphometric analysis of brain magnetic resonance images has shown a grey matter volume increase in the insula and upper brain stem, and a decrease in the ACC of panic patients at rest, as compared to healthy controls. The insula and the ACC detect interoceptive stimuli, which are overestimated by panic patients. It is suggested that these brain areas and the PAG are involved in the pathophysiology of panic disorder. (C) 2008 Elsevier Ltd. All rights reserved.

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Leather industries which promote hide stabilization by the conventional chrome-tanning process are a major source of pollution because of the resultant chromium-rich wastes. In this work, an extensive characterization of such a chromium-rich waste sludge is presented, regarding its chemical composition (XRF), crystalline phase contents (XRD), organic carbon content (TOC), thermal behavior by thermogravimetry (TG) and differential scanning calorimetry (DSC), as well as its stability under chemical attack (the concentration of important ions in the leachates being determined by capillary electrophoresis) and when submitted to temperatures as high as 1100 degrees C, in air. The material showed the tendency to produce some undesirable, and previously non-detected hexavalent chromium when exposed to high temperatures, but after washing off the soluble salts and the elimination of the organic matter by firing, the resultant material was succesfully tested as a ceramic pigment in a conventional glaze composition usually employed in the ceramic the industry. (C) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

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Leptospirosis is a widespread re-emerging zoonosis of human and veterinary concern. It has been shown that virulent leptospires protect themselves against the host`s innate immune system, a strategy that allows the bacteria to reach immunologically safe environments. Although extensive studies on host pathogen interactions have been performed, little is known on how leptospires deal with host immune attack. In a previous work, we demonstrated the ability of leptospires to bind human plasminogen (PLC), that after treatment with activators, conferred plasmin (PLA) activity on the bacteria surface. In this study, we show that the PLA activity associated to the outer surface of Leptospira could interfere with the host immune attack by conferring some evasion advantage during infection. We demonstrate that PLA-coated leptospires interfere with complement Ob and IgG depositions on the bacterial surface, probably through the degradation of these components, thus diminishing opsonization process. Similar decrease on the deposition was observed when normal and immune sera from patients diagnosed with leptospirosis were employed as a source of IgG. We believe that decreasing opsonization by PLA generation might be an important aspect of the leptospiral immune escape strategy and survival. To our knowledge, this is the first proteolytic activity of plasmin associated-Leptospira related to anti-opsonic properties reported to date. (C) 2011 Elsevier Ltd. All rights reserved.

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Individuals with cariogenic diet can also consume erosive beverages. Thus, it seems necessary to investigate a possible caries/erosion interaction. To test in situ/ex vivo a combination of these challenges, 11 subjects wore intraoral appliances containing four enamel blocks randomly assigned. In the first 2-week phase, the appliances were immersed in a cola drink 3 times/day. Two blocks were free of plaque (erosion only: EO) and two blocks were covered with plaque (erosion + plaque: EP). In the second 2-week phase, four new blocks were all covered with plaque and subjected to a sucrose solution 8 times/day. Among the four new blocks, two were also subjected to the cola drink 3 times/day (erosion + caries: EC) while the other two were not (caries only: CO). Thus, in EO, the specimens were fixed at the intraoral appliance level. In EP, EC and CO they were fixed 1.0 mm under the appliance level and covered with plastic meshes for dental plaque accumulation. Changes in wear and hardness were measured. Data were tested using ANOVA and Tukey`s test (p < 0.05). Mean values of wear (mu m) and change in hardness (kp/mm(2)) were: EO 4.82/310; EP 0.14/48; EC 0.34/245; CO 0.42/309. With respect to surface softening, EP and EC differed significantly from each other and from EO and CO, which did not differ significantly. EO presented significantly higher wear than the other groups. The data suggest that the presence of dental plaque can decrease the acid attack of an erosive drink and the association of erosive and cariogenic challenges showed less enamel alterations when compared to erosive or cariogenic challenges only. Copyright (C) 2008 S. Karger AG, Basel

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Background: We compared the circulating levels of matrix metalloproteinase (MMP)-2. MMP-9, tissue inhibitors of metal loproteinase (TIMP)-1, TIMP-2, and MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios in migraine patients without aura (MWA) and in migraine patients with aura (MA) with those found in healthy subjects (controls). Methods: We studied 80 migraine (40 MWA and 40 MA) women and 40 controls. Pro-MMP-2 levels were determined by zymography and MMP-9, TIMP-1, and TIMP-2 levels were determined by ELISA. Results: While we found similar TIMP-2 levels, higher plasma pro-MMP-2 and pro-MMP-2/TIMP-2 ratios were found in MWA and MA patients compared with controls (P<0.05). Higher TIMP-1 levels and lower MMP-9/TIMP-1 ratio were found in MA, but not in MWA, patients compared with controls (P<0.05). We found no significant differences when patients without headache attack were compared with patients having a headache attack (all P<0.05). Conclusions: We showed an increased net MMP-2 activity in MWA and MA. The increased MMP-9/TIMP-1 ratios in MWA patients contrast with the lower MMP-9/TIMP-1 ratios in MA patients and may reflect pathophysiological differences between these conditions. (C) 2009 Elsevier B.V. All rights reserved.

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Glutamate is the major excitatory neurotransmitter in the retina and is removed from the extracellular space by an energy-dependent process involving neuronal and glial cell transporters. The radial glial Muller cells express the glutamate transporter, GLAST, and preferentially accumulate glutamate. However, during an ischaemic episode, extracellular glutamate concentrations may rise to excitotoxic levels. Is this catastrophic rise in extracellular glutamate due to a failure of GLAST? Using immunocytochemistry, we monitored the transport of the glutamate transporter substrate, D-aspartate, in the retina under normal and ischaemic conditions. Two models of compromised retinal perfusion were compared: (1) Anaesthetised rats had their carotid arteries occluded for 7 days to produce a chronic reduction in retinal blood flow. Retinal function was assessed by electroretinography. D-aspartate was injected into the eye for 45 min, Following euthanasia, the retina was processed for D-aspartate. GLAST and glutamate immunocytochemistry. Although reduced retinal perfusion suppresses the electroretinogram b-wave, neither retinal histology, GLAST expression, nor the ability of Muller cells to uptake D-aspartate is affected. As this insult does not appear to cause excitotoxic neuronal damage, these data suggest that GLAST function and glutamate clearance are maintained during periods of reduced retinal perfusion. (2) Occlusion of the central retinal artery for 60 min abolishes retinal perfusion, inducing histological damage and electroretinogram suppression. Although GLAST expression appears to be normal. its ability to transport D-aspartate into Muller cells is greatly reduced. Interestingly, D-aspartate is transported into neuronal cells, i.e. photoreceptors, bipolar and ganglion cells. This suggests that while GLAST is vitally important for the clearance of excess extracellular glutamate, its capability to sustain inward transport is particularly susceptible to an acute ischaemic attack. Manipulation of GLAST function could alleviate the degeneration and blindness that result from ischaemic retinal disease. (C) 2001 Elsevier Science Ltd, All rights reserved.

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In its first term, the Howard government hired Australasian Research Strategies (ARS), headed by pollster Mark Textor, to conduct market research for several Commonwealth departments and agencies. This was, the Labor Opposition claimed, a case of the Liberals handing jobs to their 'mates'. Textor played a key role in the Liberals' 1996 and 1998 federal election campaigns. However, Labor's attack rings hollow since in the 1980s the Hawke government similarly contracted Rod Cameron's ANOP to conduct opinion research for Commonwealth departments and agencies. At the time Cameron was Labor's strategic pollster and centrally involved in planning Labor election campaigns. On both sides of Australian politics, governments have begun to channel patronage towards their party's pollsters. In this research note, we suggest that this development cannot be explained as 'jobs for the boys'. Instead, this new form of patronage has its roots in the vital role that pollsters now play in guiding election campaigns, and in the commercial reality that Australian politics provides too little work to sustain specialist political pollsters. Parties in government now appear to utilise incumbency to sustain an ongoing relationship with the commercial polling organisations like ANOP and ARS to whom they will entrust much of the planning of their campaign for re-election.

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Background: Tobacco cessation after acute myocardial infarction (AMI) substantially improves outcome but how effective individual programmes are needs to be established. To date, few studies have examined this factor. Aims: To assess the outcome of two smoking cessation programmes after AMI. Methods: One hundred and ninety-eight current smokers admitted to coronary care with an AMI participated in a randomized controlled study comparing two outpatient tobacco interventions, the Stanford Heart Attack Staying Free (SF) programme and a Usual Care (UC) programme. Results: Log-rank analyses revealed that patients in the SF programme were retained longer (P < 0.001) and had higher cotinine validated abstinence rates (P < 0.001) compared with patients in the UC programme. Twelve months after intervention, 39% of the SF programme compared with 2% of the UC programme demonstrated cotinine validated tobacco cessation, representing a significant reduced relapse rate in the SF programme (chi (2), P < 0.001). Conclusions: The SF smoking cessation programme initiated in hospital can significantly reduce smoking rates at 12 months after myocardial infarction. Although superior to the UC quit programme, Australian outcomes were lower than the American programme originators' published outcomes.

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Silica xerogels were prepared by a sol-gel process catalyzed by acid with tetraethylorthosilicate, and using an organic covalent ligand template (methyltriethoxysilane) or a noncovalent template C6 surfactant (triethylhexylammonium bromide). The influence of hydrotreatment on the structure of templated xerogels is examined in terms of surface area, micropore volume, average pore size, and pore size distribution, and compared against a blank xerogel (nontemplated). The role of surface functional groups was evaluated using Si-29 nuclear magnetic resonance. The structural integrity of the xerogel was maintained to a large extent in samples that had a high contribution of Q(4) species (siloxane groups). Xerogel matrix densification occurred when there was a large concentration of Q(3) and Q(2) species (silanol groups), which also were responsible for increased hydrophilicity. The templated xerogels resulted in up to a 25% concentration of methyl functional groups (T-3 and T-2 species), leading to hydrophobic xerogels. The best results in terms of structural integrity and hydrophobicity were obtained with templated xerogels prepared with the C6 surfactant. The results in this study suggest that surfactant-enhanced condensation reactions lead to structures with a high contribution of Q(4) groups, which are not susceptible to water attack, but are strong enough to oppose matrix densification during rehydration.

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The synthesis, spectroscopic properties, and chemical reactions of the stable (neopentylimino)-, (mesitylimino)-, and (o-tert-butylphenylimino)propadienones (6) are reported. Nucleophilic addition of amines affords the malonic amidoamidines 7 and 8. 3,5-Dimethylpyrazole reacts analogously to form 9b. Addition of 1,2-dimethylhydrazine produces pyrazolinones 10-12. Addition of N,Y'-dimethyldiaminoethane, -propane, and -butane gives diazepine, diazocine, and diazonine derivatives 13-15, respectively (X-ray structures of 13c, 14a, and 15a are available). The mesoionic pyridopyrimidinium olates IS are obtained by addition of 2-(methylamino)pyridine (X-ray structure of 18b available). Primary 2-aminopyridines afford the pyridopyrimidininones 20-29 and 31 (X-ray structure of 21a available), and 2-aminopyrimidines and 2-aminopyrazine afford pyrimidopyrimidinones and pyrazinopyrimidinones 33-35. Pyrimidoisoquinolinone 36 results from 1-aminoisoquinoline and pyridoquinolinone 40 from 8-aminoquinoline. 2-Aminothiazoline and 2-aminothiazole afford thiazolopyrimidinone derivatives 41-43 (X-ray structure of 43a available).

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We tested the hypothesis that early-planted seedbeds of rioe are mere heavily infested with brown planthopper (BPH) than later seedbeds, and that transplanted plants with lBPH are a source of subsequent population increase and possible outbreaks. The experiments were conducted at CARDI and Takeo province in wet season 2000 and early wet 2 season 200 I. BPH at O. 25. 50, 100, 200 1m were infested onto plants with low and high fertilizer treatments. Rice seeds of varieties moderately and highly susceptible to BPH were sown 3 weeks early, 2 weeks early, at the normal time, and later than normal (5 weeks) and treated with low and high fertilizer rates. At Takeo, the 3< weeks early seedbeds were infested by BPH migration, and both varieties with high fertilizer caught more immigrant insects and subsequently had damaging outbreaks of BPH in the third generation. At CARDl, no seedbeds were infested with immigrant BPH. Seedbeds in areas with continuous cropping of rice have a high risk of BPH attack, Seedlings infested with 200, 100, and 50 BPI[/m2 resulted in death of the plant. Plants with 100 and 200 BPH/m'! were kj[Jed sooner. With 25 BPIVm2 plants were not kllled, but subsequent population increase caused yi eld reduction. Yield loss was high ill higlh fertilizer treated plants. Key words , ,

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Shoaling with familiar individuals may have many benefits including enhanced escape responses or increased foraging efficiency. This study describes the results of two complimentary experiments. The first utilised a simple binary choice experiment to determine if rainbowfish (Melanotaenia spp.) preferred to shoal with familiar individuals or with strangers. The second experiment used a free range situation where familiar and unfamiliar individuals were free to intermingle and were then exposed to a predator threat. Like many other small species of fish, rainbowfish were capable of identifying and distinguishing between individuals and choose to preferentially associate with familiar individuals as opposed to strangers. Contrary to expectations. however. rainbowrish did not significantly increase their preference for familiar individuals in the presence of a stationary predator model. Griffiths [J Fish Biol (1997) 51:489-4951 conducted similar studies under semi-natural conditions examining, the shoaling preferences of European minnows and showed similar results. Both the current study and that of Griffiths were conducted using predator wary populations of fish. It is suggested that, in predator sympatric populations, the benefits of shoaling with familiar individuals are such that it always pays to stay close to familiar individuals even when the probability If predator attack is remote.