972 resultados para Continuous phase modulation


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Background: The purpose of this study was to evaluate the effect of long-term use of oral contraceptives (DC) containing 0.20 mg of ethinylestradiol (EE) combined with 0.15 mg of gestodene (GEST) on the peak aerobic capacity and at the anaerobic threshold (AT) level in active and sedentary young women. Study Design: Eighty-eight women (23 +/- 2.1 years old) were divided into four groups active-OC (G1), active-NOC (G2), sedentary-OC (G3) and sedentary-NOC (G4) and were submitted to a continuous ergospirometric incremental test on a cycloergometer with 20 to 25 W min(-1) increments. Data were analyzed by two-way ANOVA with Tukey post hoc test. Level of significance was set at 5%. Results: The OC use effect for the variables relative and absolute oxygen uptake VO(2) mL kg(-1) min(-1); VO(2), L min(-1), respectively), carbon dioxide output (VCO(2), L min(-1)), ventilation (VE, L min(-1)), heart rate (HR, bpm), respiratory exchange ratio (RER) and power output (W) data, as well as the interaction between OC use and exercise effect on the peak of test and at the AT level did not differ significantly between the active groups (G1 and G2) and the sedentary groups (G3 and G4). As to the exercise effect, for all variables studied, it was noted that the active groups presented higher values for the variables VO(2), VCO(2), VE and power output (p<.05) than the sedentary groups. The RER and HR were similar (p>.05) at the peak and at the AT level between G1 vs. G3 and G2 vs. G4. Conclusions: Long-term use of OC containing EE 0.20 mg plus GEST 0.15 mg does not affect aerobic capacity at the peak and at the AT level of exercise tests. (C) 2010 Elsevier Inc. All rights reserved.

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Cannabis sativa, the most widely used illicit drug, has profound effects on levels of anxiety in animals and humans. Although recent studies have helped provide a better understanding of the neurofunctional correlates of these effects, indicating the involvement of the amygdala and cingulate cortex, their reciprocal influence is still mostly unknown. In this study dynamic causal modelling (DCM) and Bayesian model selection (BMS) were used to explore the effects of pure compounds of C. sativa [600 mg of cannabidiol (CBD) and 10 mg Delta(9)-tetrahydrocannabinol (Delta(9)-THC)] on prefrontal-subcortical effective connectivity in 15 healthy subjects who underwent a double-blind randomized, placebo-controlled fMRI paradigm while viewing faces which elicited different levels of anxiety. In the placebo condition, BMS identified a model with driving inputs entering via the anterior cingulate and forward intrinsic connectivity between the amygdala and the anterior cingulate as the best fit. CBD but not Delta(9)-THC disrupted forward connectivity between these regions during the neural response to fearful faces. This is the first study to show that the disruption of prefrontal-subocrtical connectivity by CBD may represent neurophysiological correlates of its anxiolytic properties.

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Several neuropsychiatry disorders have shown a sexual dimorphism in their incidence, symptom profile and therapeutic response. A better understanding of the impact of sex hormones in emotional processing sexual dimorphism could bring tight to this important clinical finding. Some studies have provided evidence of sex differences in the identification of emotional faces, however, results are inconsistent and such inconsistency could be related to the lack of experimental control of the sex hormone status of participants. More recently, a few studies evaluated the modulation of facial emotion recognition by the phase of the menstrual cycle and sex hormones, however, none of them directly compared these results with a group of men. We evaluated the accuracy of facial emotion recognition in 40 healthy volunteers. Eleven women were assigned to early follicular group, nine women to the ovulatory group and 10 women to luteal group, depending on the phase of menstrual cycle, and a group of 10 men were also evaluated. Estrogen, progesterone and testosterone levels were assessed. The performance of the groups in the identification of emotional faces varied depending on the emotion. Early follicular group were more accurate to perceive angry faces than all other groups. Sadness was more accurately recognized by early follicular group than by luteal group and regarding the recognition of fearful faces a trend to a better performance and a significantly higher accuracy was observed, respectively, in the early follicular group and in the ovulatory group, in comparison to men. In women, estrogen negatively correlated to the accuracy in perception of angry mate faces. Our results indicate sex hormones to be implicated in a sexual dimorphism in facial emotion recognition, and highlight the importance of estrogen specifically in the recognition of negative emotions such as sadness, anger and fear. (C) 2009 Elsevier Ltd. All rights reserved.

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Context: Cannabis sativa use can impair verbal learning, provoke acute psychosis, and increase the risk of schizophrenia. It is unclear where C sativa acts in the human brain to modulate verbal learning and to induce psychotic symptoms. Objectives: To investigate the effects of 2 main psychoactive constituents of C sativa, Delta 9-tetrahydrocannabinol (Delta 9-THC) and cannabidiol, on regional brain function during verbal paired associate learning. Design: Subjects were studied on 3 separate occasions using a block design functional magnetic resonance imaging paradigm while performing a verbal paired associate learning task. Each imaging session was preceded by the ingestion of Delta 9-THC (10 mg), cannabidiol (600 mg), or placebo in a double-blind, randomized, placebo-controlled, repeated-measures, within-subject design. Setting: University research center. Participants: Fifteen healthy, native English-speaking, right-handed men of white race/ethnicity who had used C sativa 15 times or less and had minimal exposure to other illicit drugs in their lifetime. Main Outcome Measures: Regional brain activation ( blood oxygen level-dependent response), performance in a verbal learning task, and objective and subjective ratings of psychotic symptoms, anxiety, intoxication, and sedation. Results: Delta 9-Tetrahydrocannabinol increased psychotic symptoms and levels of anxiety, intoxication, and sedation, whereas no significant effect was noted on these parameters following administration of cannabidiol. Performance in the verbal learning task was not significantly modulated by either drug. Administration of Delta 9-THC augmented activation in the parahippocampal gyrus during blocks 2 and 3 such that the normal linear decrement in activation across repeated encoding blocks was no longer evident. Delta 9-Tetrahydrocannabinol also attenuated the normal time-dependent change in ventrostriatal activation during retrieval of word pairs, which was directly correlated with concurrently induced psychotic symptoms. In contrast, administration of cannabidiol had no such effect. Conclusion: The modulation of mediotemporal and ventrostriatal function by Delta 9-THC may underlie the effects of C sativa on verbal learning and psychotic symptoms, respectively.

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Although the effects of cannabis on perception are well documented, little is known about their neural basis or how these may contribute to the formation of psychotic symptoms. We used functional magnetic resonance imaging (fMRI) to assess the effects of Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) during visual and auditory processing in healthy volunteers. In total, 14 healthy volunteers were scanned on three occasions. Identical 10mg THC, 600mg CBD, and placebo capsules were allocated in a balanced double-blinded pseudo-randomized crossover design. Plasma levels of each substance, physiological parameters, and measures of psychopathology were taken at baseline and at regular intervals following ingestion of substances. Volunteers listened passively to words read and viewed a radial visual checkerboard in alternating blocks during fMRI scanning. Administration of THC was associated with increases in anxiety, intoxication, and positive psychotic symptoms, whereas CBD had no significant symptomatic effects. THC decreased activation relative to placebo in bilateral temporal cortices during auditory processing, and increased and decreased activation in different visual areas during visual processing. CBD was associated with activation in right temporal cortex during auditory processing, and when contrasted, THC and CBD had opposite effects in the right posterior superior temporal gyrus, the right-sided homolog to Wernicke`s area. Moreover, the attenuation of activation in this area (maximum 61, -15, -2) by THC during auditory processing was correlated with its acute effect on psychotic symptoms. Single doses of THC and CBD differently modulate brain function in areas that process auditory and visual stimuli and relate to induced psychotic symptoms. Neuropsychopharmacology (2011) 36, 1340-1348; doi:10.1038/npp.2011.17; published online 16 March 2011

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Rhinosinusal polyps physiopathology is not fully understand, despite numerous hypotheses regarding its inflammatory process. Aims: a prospective study regarding the gene expression of proteins: anexin-1 and galectin-1, which has an anti-inflammatory action and is modulated by steroids. Materials and Methods: eleven patients with rhinosinusal polyps suffered a biopsy of their polyps at two moments: in the absence of systemic steroids and during its use. In the two samples we assessed the expression of these genes and compared it to the normal nasal mucosa in the middle meatus. Results: We noticed that the mean expression of the genes which code anexin-1 and galectin-1 was predominantly increased, regardless of the use of steroids in relation to the control nasal mucosa. Notwithstanding, in polyps without the use of steroids, the mean gene expression of anexin-1 was significantly higher than in the polyps which were under the use of steroids. Regarding galectin-1, there was no significant difference between the expression mean values before and after the use of systemic steroids. Conclusion: The genes present an expression increase in the polyp mucosa, regardless of the use of steroids; nonetheless, the relationship of these two genes of anti-inflammatory proteins with steroids did not happen the same way.

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Background: Cigarette smoke exposure is considered an important negative prognostic factor for chronic rhinosinusitis (CRS) patients. However, there is no clear mechanistic evidence implicating cigarette smoke exposure in the poor clinical evolution of the disease or in the maintenance of the inflammatory state characterizing CRS. This study aimed to evaluate the effects of cigarette smoke exposure on respiratory cilia differentiation. Methods: Monse nasal septal epithelium cultures grown at an air-liquid interface were used as a model of respiratory epithelium. After 5 days of cell growth, cultures were exposed to air on the apical surface. Additionally, cigarette smoke condensate (CSC; the particulate phase of tobacco smoke) or cigarette smoke extract (CSE; the volatile phase) Were diluted in the basolateral compartment in different concentrations. After 15 days of continuous exposure, scanning electron microscopy and immunofluorescence for type IV tubulin were used to determine presence and maturation of cilia. Transepithelial resistance was also recorded to evaluate confluence and physiological barrier integrity. Results: CSC and CSE impair ciliogenesis in a dose-dependent manner with notable effects in concentrations higher than 30 mu g/mL, yielding >70% nonciliation and shorter cilia compared With control. No statistical difference on transepithelial resistance was evident. Conclusion: CSC and CSE exposure negatively impacts ciliogenesis of respiratory cells at concentrations not effecting transepithelial resistance. The impairment on ciliogenesis reduce the mucociliary clearance apparatuts after injury and/or infection and may explain the poor response to therapy for CRS patients exposed to tobacco smoke.

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Purpose: To evaluate the short-term (10 months) safety of a single intravitreal injection of autologous bone marrow-derived mononuclear cells in patients with retinitis pigmentosa or cone-rod dystrophy. Methods: A prospective, Phase I, nonrandomized, open-label study including 3 patients with retinitis pigmentosa and 2 patients with cone-rod dystrophy and an Early Treatment Diabetic Retinopathy Study best-corrected visual acuity of 20/200 or worse. Evaluations including best-corrected visual acuity, full-field electroretinography, kinetic visual field (Goldman), fluorescein and indocyanine green angiography, and optical coherence tomography were performed at baseline and 1, 7, 13, 18, 22, and 40 weeks after intravitreal injection of 10 X 10(6) autologous bone marrow-derived mononuclear cells (0.1 mL) into 1 study eye of each patient. Results: No adverse event associated with the injection was observed. A 1-line improvement in best-corrected visual acuity was measured in 4 patients 1 week after injection and was maintained throughout follow-up. Three patients showed undetectable electroretinography responses at all study visits, while 1 patient demonstrated residual responses for dark-adapted standard flash stimulus (a wave amplitude approximately 35 mu V), which remained recordable throughout follow-up, and 1 patient showed a small response (a wave amplitude approximately 20 mu V) recordable only at Weeks 7, 13, 22, and 40. Visual fields showed no reduction (with a Goldman Standard V5e stimulus) for any patient at any visit. No other changes were observed on optical coherence tomography or fluorescein and indocyanine green angiograms. Conclusion: Intravitreal injection of autologous bone marrow-derived mononuclear cells in eyes with advanced retinitis pigmentosa or cone-rod dystrophy was associated with no detectable structural or functional toxicity over a period of 10 months. Further studies are required to investigate the role, if any, of autologous bone marrow-derived mononuclear cell therapy in the management of retinal dystrophies. RETINA 31: 1207-1214, 2011

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Previously, it was demonstrated that the heme/heme oxygenase (HO)/carbon monoxide (CO) pathway inhibits neutrophil recruitment during the inflammatory response. Herein, we addressed whether the inhibitory effect of the HO pathway on neutrophil adhesion and migration involves the reduction of intracellular adhesion molecule type (ICAM)-1 and beta(2)-integrin expression. Mice pretreated with a specific inhibitor of inducible HO (HO-1), zinc protoporphyrin (ZnPP) IX, exhibit enhanced neutrophil adhesion and migration induced by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS). These findings are associated with an increase in ICAM-1 expression on mesentery venular endothelium. In accordance, HO-1 inhibition did not enhance LPS-induced neutrophil migration and adhesion in ICAM-1-deficient mice. Furthermore, the treatment with a CO donor (dimanganese decacarbonyl, DMDC) that inhibits adhesion and migration of the neutrophils, reduced LPS-induced ICAM-1 expression. Moreover, neither DMDC nor ZnPP IX treatments changed LPS-induced beta(2)-integrin expression on neutrophils. The effect of CO on ICAM-1 expression seems to be dependent on soluble guanylate cyclase (sGC) activation, since 1H-(1,2,4)oxadiazolo (4,3-a)quinoxalin-1-one (sGC inhibitor) prevented the observed CO effects. Finally, it was observed that the nitric oxide (NO) anti-inflammatory effects on ICAM-1 expression appear to be indirectly mediated by HO-1 activation, since the inhibition of HO-1 prevented the inhibitory effect of the NO donor (S-nitroso-N-acetylpenicillamine) on LPS-induced ICAM-1 expression. Taken together, these results suggest that CO inhibits ICAM-1 expression on endothelium by a mechanism dependent on sGC activation. Thus, our findings identify the HO-1/CO/guanosine 3`5`-cyclic monophosphate pathway as a potential target for the development of novel pharmacotherapy to control neutrophil migration in inflammatory diseases.

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The identification of early markers that predict the response to anti-tuberculosis treatment would facilitate evaluation of new drugs and improve patient management. This study aimed to determine whether selected acute phase proteins and micronutrients measured at the time of diagnosis and during the first weeks of treatment could predict treatment responses during the 2-month standard intensive phase of therapy. For this purpose, alpha 1-antitrypsin, alpha 1-acid gtycoprotein, alpha 2-macroglobutin, C-reactive protein, C3, C4, zinc, copper and selenium concentrations were measured in Brazilian patients with smear-positive tuberculosis at the time of diagnosis and 1, 3, 5 and 8 weeks after initiation of therapy. Patients were classified into fast (n = 29), intermediate (n = 18) and slow responders (n = 10) if they were smear-negative at 3, 5 or 8 weeks of treatment. alpha 1-acid gtycoprotein on enrolment and 1 week of treatment, alpha 1-antitrypsin at week 1 and C-reactive protein and C3 after 3 weeks of therapy were higher in slow responders than in fast responders. alpha 1-antitrypsin and alpha 1-acid glycoprotein may be helpful in predicting treatment response at the time of initiation of therapy, and could be used as early markers to identify patients with an increased likelihood of treatment failure. (C) 2008 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

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When infected with Trypanosoma cruzi, Beagle dogs develop symptoms similar to those of Chagas disease in human beings, and could be an important experimental model for a better understanding of the immunopathogenic mechanisms involved in chronic chagasic infection. This study evaluates IL-10, IFN-gamma and TNF-alpha production in the sera, culture supernatant, heart and cervical lymph nodes and their correlation with cardiomegaly, cardiac inflammation and fibrosis in Beagle dogs infected with T. cruzi. Pathological analysis showed severe splenomegaly, lymphadenopathy and myocarditis in all infected dogs during the acute phase of the disease, with cardiomegaly, inflammation and fibrosis observed in 83% of the animals infected by T. cruzi during the chronic phase. The data indicate that infected animals producing IL-10 in the heart during the chronic phase and showing high IL-10 production in the culture supernatant and serum during the acute phase had lower cardiac alterations (myocarditis, fibrosis and cardiomegaly) than those with high IFN-gamma and TNF-alpha levels. These animals produced low IL-10 levels in the culture supernatant and serum during the acute phase and did not produce IL-10 in the heart during the chronic phase of the disease. Our findings showed that Beagle dogs are a good model for studying the immunopathogenic mechanism of Chagas disease, since they reproduce the clinical and immunological findings described in chagasic patients. The data suggest that the development of the chronic cardiac form of the disease is related to a strong Th1 response during the acute phase of the disease, while the development of the indeterminate form results from a blend of Th1 and Th2 responses soon after infection, suggesting that the acute phase immune response is important for the genesis of chronic cardiac lesions. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

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Context In 2007, the effects of the autologous nonmyeloablative hematopoietic stem cell transplantation (HSCT) in 15 patients with type 1 diabetes mellitus (DM) were reported. Most patients became insulin free with normal levels of glycated hemoglobin A(1c) (HbA(1c)) during a mean 18.8-month follow-up. To investigate if this effect was due to preservation of beta-cell mass, continued monitoring was performed of C-peptide levels after stem cell transplantation in the 15 original and 8 additional patients. Objective To determine C-peptide levels after autologous nonmyeloablative HSCT in patients with newly diagnosed type 1 DM during a longer follow-up. Design, Setting, and Participants A prospective phase 1/2 study of 23 patients with type 1 DM(aged 13-31 years) diagnosed in the previous 6 weeks by clinical findings with hyperglycemia and confirmed by measurement of serum levels of anti glutamic acid decarboxylase antibodies. Enrollment was November 2003-April 2008, with follow-up until December 2008 at the Bone Marrow Transplantation Unit of the School of Medicine of Ribeirao Preto, Ribeirao Preto, Brazil. Hematopoietic stem cells were mobilized via the 2007 protocol. Main Outcome Measures C-peptide levels measured during the mixed-meal tolerance test, before, and at different times following HSCT. Secondary end points included morbidity and mortality from transplantation, temporal changes in exogenous insulin requirements, and serum levels of HbA1c. Results During a 7- to 58-month follow-up (mean, 29.8 months; median, 30 months), 20 patients without previous ketoacidosis and not receiving corticosteroids during the preparative regimen became insulin free. Twelve patients maintained this status for a mean 31 months (range, 14-52 months) and 8 patients relapsed and resumed insulin use at low dose (0.1-0.3 IU/kg). In the continuous insulin-independent group, HbA(1c) levels were less than 7.0% and mean (SE) area under the curve (AUC) of C-peptide levels increased significantly from 225.0 (75.2) ng/mL per 2 hours pretransplantation to 785.4 (90.3) ng/mL per 2 hours at 24 months posttransplantation (P<.001) and to 728.1 (144.4) ng/mL per 2 hours at 36 months (P=.001). In the transient insulin-independent group, mean (SE) AUC of C-peptide levels also increased from 148.9 (75.2) ng/mL per 2 hours pretransplantation to 546.8 (96.9) ng/mL per 2 hours at 36 months (P=.001), which was sustained at 48 months. In this group, 2 patients regained insulin independence after treatment with sitagliptin, which was associated with increase in C-peptide levels. Two patients developed bilateral nosocomial pneumonia, 3 patients developed late endocrine dysfunction, and 9 patients developed oligospermia. There was no mortality. Conclusion After a mean follow-up of 29.8 months following autologous nonmyeloablative HSCT in patients with newly diagnosed type 1 DM, C-peptide levels increased significantly and the majority of patients achieved insulin independence with good glycemic control. Trial Registration clinicaltrials.gov Identifier: NCT00315133

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The infection with Trypanosoma cruzi leads to a vigorous and apparently uncontrolled inflammatory response in the heart. Although the parasites trigger specific immune response, the infection is not completely cleared out, a phenomenon that in other parasitic infections has been attributed to CD4(+)CD25(+) T cells (Tregs). Then, we examined the role of natural Tregs and its signaling through CD25 and GITR in the resistance against infection with T. cruzi. Mice were treated with mAb against CD25 and GITR and the parasitemia, mortality and heart pathology analyzed. First, we demonstrated that CD4(+)CD25(+)GITR(+)Foxp3(+) T cells migrate to the heart of infected mice. The treatment with anti-CD25 or anti-GITR resulted in increased mortality of these infected animals. Moreover, the treatment with anti-GITR enhanced the myocarditis, with increased migration of CD4(+), CD8(+), and CCR5(+) leukocytes, TNF-alpha production, and tissue parasitism, although it did not change the systemic nitric oxide synthesis. These data showed a limited role for CD25 signaling in controlling the inflammatory response during this protozoan infection. Also, the data suggested that signaling through GITR is determinant to control of the heart inflammation, parasite replication, and host resistance against the infection. (C) 2008 Elsevier Masson SAS. All rights reserved.