973 resultados para Prime-boost immunization
Resumo:
Evidence for expectancy-based priming in the pronunciation task was provided in three experiments. In Experiments 1 and 2, a high proportion of associatively related trials produced greater associative priming and superior retrieval of primes in a subsequent test of memory for primes, whereas high- and low-proportion groups showed comparable repetition benefits in perceptual identification of previously presented primes. In Experiment 2, the low-proportion condition had few associatively related pairs hut many identity pairs. In Experiment 3, identity priming was greater in a high- than a low-identity proportion group, with similar repetition benefits and prime retrieval responses for the two groups. These results indicate that when the prime-target relationship is salient, subjects strategically vary their processing of the prime according to the nature of the prime-target relationship.
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Background and Purpose. Activity of the trunk muscles is essential for maintaining stability of the lumbar spine because of the unstable structure of that portion of the spine. A model involving evaluation of the response of the lumbar multifidus and abdominal muscles to leg movement was developed to evaluate this function. Subjects. To examine this function in healthy persons, 9 male and 6 female subjects (mean age = 20.6 years, SD = 2.3) with no history of low back pain were studied. Methods. Fine-wire and surface electromyography electrodes were used to record the activity of selected trunk muscles and the prime movers for hip flexion, abduction, and extension during hip movements in each of these directions. Results. Trunk muscle activity occurring prior to activity of the prime mover of the limb was associated with hip movement in each direction. The transversus abdominis (TrA) muscle was invariably the first muscle that was active. Although reaction time for the TrA and oblique abdominal muscles was consistent across movement directions, reaction time for the rectus abdominis and multifidus muscles varied with the direction of limb movement. Conclusion and Discussion. Results suggest that the central nervous st stem deals with stabilization of the spine by contraction of the abdominal and multifidus muscles in anticipation of reactive forces produced by limb movement. The TrA and oblique abdominal muscles appear to contribute to a function not related to the direction of these forces.
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Purpose: Animal models of diseases are extremely important in the study of the physiopathogenesis of human diseases and for testing novel therapeutic interventions. The present study aimed to develop an animal model that simulates human allergic conjunctivitis and to study how allergic response may be influenced by the allergen dose used for immunization and by genetic factors. Methods: Sixty C57Bl/6 mice and 60 BALB/c mice were immunized with placebo, or 5 mu g or 500 mu g of allergen derived from Dermatophagoides pteronyssinus. After ocular challenge, the mice were examined in order to clinically verify the occurrence or not of conjunctivitis. Material obtained from animals was used for total and specific IgE and IgG1 dosage, for assays of Der p-specific lymphocyte proliferation and supernatant cytokine dosage, and for histopathological evaluation of conjunctiva. Results: We developed a murine model of allergic conjunctivitis induced by D. pteronyssinus. The model is similar to human disease both clinically and according to laboratory findings. In mouse, conjunctivitis was associated with a Th2 cytokine profile. However, IL-10 appeared to be involved with disease blockade. Mice of different strains have distinct immune responses, depending on the sensitization dose. Conclusions: The murine model developed is suitable for the study of immunopathogenesis and as a template for future therapies. Using BALB/c and C57BL/6 mice, we demonstrated that genetic factors play a role in determining susceptibility and resistance, as well as in establishing the allergen concentration needed to induce or to block disease development.
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Sm14 and paramyosin are two major Schistosoma mansoni vaccine candidate antigens. Recently, we have identified Sm14 and paramyosin epitopes that are recognized by T cells of resistant individuals living in endemic areas for schistosomiasis. Herein, mice were immunized with these peptides separately or in association in order to evaluate their vaccine potential. Immunization of mice with Sm14 peptides alone or mixed with paramyosin peptides was able to induce 26%-36.7% or 28%-29.2% of worm burden reduction, 67% or 46% of intestinal eggs reduction and also 54%-61% or 43%-52% of liver pathology reduction, respectively. Protection was associated with a Th1 type of immune response induced by Sm14 peptide immunization. In contrast, paramyosin peptide vaccination did not engender protective immunity or liver pathology reduction and immunization was associated with a Th2 type of immune response. (C) 2008 Elsevier B.V. All rights reserved.
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Because the structure of the spine is inherently unstable, muscle activation is essential for the maintenance of trunk posture and intervertebral control when the limbs are moved. To investigate how the central nervous system deals with this situation the temporal components of the response of the muscles of the trunk were evaluated during rapid limb movement performed in response to a visual stimulus. Fine-wire electromyography (EMG) electrodes were inserted into transversus abdominis (TrA), obliquus internus abdominis (OI) and obliquus externus abdominis (OE) of 15 subjects under the guidance of real-time ultrasound imaging. Surface electrodes were placed over rectus abdominis (RA), lumbar multifidus (MF) and the three parts of deltoid. In a standing position, ten repetitions of shoulder flexion, abduction and extension were performed by the subjects as fast as possible in response to a visual stimulus. The onset of TrA EMG occurred in advance of deltoid irrespective of the movement direction. The time to onset of EMC activity of OI, OE, RA and MF varied with the movement direction, being activated earliest when the prime action of the muscle opposed the reactive forces associated with the specific limb movement. It is postulated that the non-direction-specific contraction of TrA may be related to the control of trunk. stability independent of the requirement for direction-specific control of the centre of gravity in relation to the base of support.
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Purpose: To compare the sparing potential of cerebral hemispheres with intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) for whole-ventricular irradiation (WVI) and conventional whole-brain irradiation (WBI) in the management of localized central nervous system germ cell tumors (CNSGCTs). Methods and Materials: Ten cases of patients with localized CNSGCTs and submitted to WVI by use of IMRT with or without a ""boost"" to the primary lesion were selected. For comparison purposes, similar treatment plans were produced by use of 3D-CRT (WVI with or without boost) and WBI (opposed lateral fields with or without boost), and cerebral hemisphere sparing was evaluated at dose levels ranging from 2 Gy to 40 Gy. Results: The median prescription dose for WVI was 30.6 Gy (range, 25.2-37.5 Gy), and that for the boost was 16.5 Gy (range, 0-23.4 Gy). Mean irradiated cerebral hemisphere volumes were lower for WVI with IMRT than for 3D-CRT and were lower for WVI with 3D-CRT than for WBI. Intensity-modulated radiotherapy was associated with the lowest irradiated volumes, with reductions of 7.5%, 12.2%, and 9.0% at dose levels., compared with 3D-CRT. Intensity-modulated radiotherapy provided of 20, 30, and 40 Gy, respectively statistically significant reductions of median irradiated volumes at all dose levels (p = 0.002 or less). However, estimated radiation doses to peripheral areas of the body were 1.9 times higher with IMRT than with 3D-CRT. Conclusions: Although IMRT is associated with increased radiation doses to peripheral areas of the body, its use can spare a significant amount of normal central nervous system tissue compared with 3D-CRT or WBI in the setting of CNSGCT treatment. (C) 2010 Elsevier Inc.
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Radiotherapy following breast cancer conserving surgery decreases the risks of local recurrence. Because 85% of breast cancers relapse in or around the surgical bed there has been some debate on the need for irradiating the whole breast. Electron intraoperative radiotherapy (ELIOT) has been used as a viable alternative for conventional external radiotherapy (RT). While the former requires a single dose of 21 Gy in the tumoral bed, the latter requires 5-6 weeks of irradiation with a total dose of 50 Gy and a boost of 10 Gy that irradiates the surgical bed. Herein, we investigated whether any significant differences exist between the mammography findings obtained from patients submitted to one of the two techniques. Two groups of 30 patients each were included in this study. All patients had mammographies taken at 12 and 24 months after finishing treatment. The mammography findings evaluated were: cutaneous thickening (>2 mm), architectural distortion secondary to fibrosis, edema, calcifications (both benign and malignant), and fat necrosis. For all variables studied, there was no statistical difference between the two groups. This indicates that the mammography findings obtained in either 12- or 24-month follow-up periods after breast cancer conserving surgery are similar, regardless of which of the two radiotherapy techniques (ELIOT or RT) is employed as a treatment for breast cancer. (C) 2010 Published by Elsevier Ireland Ltd.
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AIM The cognitive deficits present in the Duchenne muscular dystrophy (DMD) are not yet well characterized. Attention, considered to be the brain mechanism responsible for the selection of sensory stimuli, could be disturbed in DMD, contributing, at least partially, to the observed global cognitive deficit. The aim of this study was to investigate attentional function in individuals with DMD. METHOD Twenty-five males (mean age 12y; SD 2y 2mo) with DMD and 25 healthy males (mean age 12y; SD 2y) were tested in a visuospatial task (Posner computerized test). They were instructed to respond as quickly as possible to a lateralized visual target stimulus with the ipsilateral hand. Their attention was automatically orientated by a peripheral prime stimulus or, alternatively, voluntarily orientated by a central spatially informative cue. RESULTS The main result obtained was that the attentional effect (sum of the benefit and the cost of attention) did not differ between the two groups in the case of automatic attention (p=0.846) but was much larger for individuals with DMD than for comparison individuals in the case of voluntary attention (p < 0.001). INTERPRETATION The large voluntary attentional effect exhibited by the participants with DMD seems similar to that of younger children, suggesting that the disease is associated with delayed maturation of voluntary attention mechanisms.
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We previously generated a panel of T helper cell 1 (Th1) clones specific for an encephalitogenic peptide of myelin proteolipid protein (PLP) peptide 139-151 (HSLGKWLGHPDKF) that induces experimental autoimmune encephalomyelitis (EAE) upon adoptive transfer. In spite of the differences in their T cell receptor (TCR) gene usage, all these Th1 clones required W144 as the primary and most critical TCR contact residue for the activation. In this study, we determined the TCR contact residues of a panel of Th2/Th0 clones specific for the PLP peptide 139-151 generated either by immunization with the PLP 139-151 peptide with anti-B7-1 antibody or by immunization with an altered peptide Q144. Using alanine-substituted peptide analogues of the native PLP peptide, we show that the Th2 clones have shifted their primary contact residue to the NH2-terminal end of the peptide. These Th2 cells do not show any dependence on the W144, but show a critical requirement for L141/G142 as their major TCR contact residue. Thus, in contrast with the Th1 clones that did not proliferate to A144-substituted peptide, the Th2 clones tolerated a substitution at position 144 and proliferated to A144 peptide. This alternative A144 reactive repertoire appears to have a critical role in the regulation of autoimmune response to PLP 139-151 because preimmunization with A144 to expand the L141/G142-reactive repertoire protects mice from developing EAE induced with the native PLP 139-151 peptide. These data suggest that a balance between two different T cell repertoires specific for same autoantigenic epitope can determine disease phenotype, i.e., resistance or susceptibility to an autoimmune disease.
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Background: The high prevalence of subjective memory impairment (SMI) in the elderly living in developed countries may be partly dependent on greater demand placed on them by new technologies. As part of a comprehensive study on cognitive impairment in a population living in the Amazon rainforest, we evaluated the prevalence of SMI and investigated the features associated with it. Methods: We evaluated 163 subjects (82 females) with a mean age of 62.3 years (50-94 years), 110 of whom were illiterate, using the answer to a single question ""Do you have memory problems?"" to classify them into groups with or without SMI. The assessment involved application of the Mini-mental State Examination (MMSE), delayed recall from the Brief Cognitive Battery designed for the evaluation of low educated and illiterate individuals, the Patient Questionnaire (PQ) of the Primary Care Evaluation of Mental Disorders (PRIME-MD), and the Happiness Analogical Scale. Results: A very high prevalence of SMI (70%) was observed, exceeding rates reported by similar studies conducted in developed countries. SMI was more frequent in women, whereas age and education did not impact on prevalence. Subjects with SMI had significantly more somatic and psychiatric symptoms on the PQ, as well as lower means on the MMSE, but not on the delayed recall test. Multiple logistic regressions showed that the most important factor associated with the presence of SMI was a high score on the PQ (OR: 3.84, p = 0.011). Conclusion: Psychological and somatic symptoms may be the principal cause of SMI in this population.
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Introduction: Data on epidemiology of HPV infection are needed for the development of human papillomavirus (HPV) vaccine recommendations, especially in countries where HPV vaccination is not yet included in public vaccination programs. The aim of this study was to determine the prevalence of serum antibodies to HPV types 6, 11, 16, and 18 and associated factors among young women after birth of the first child. Methods: This cross-sectional study was carried out in a large public maternity hospital in Sao Paulo, Brazil. Three hundred one women aged 15 to 24 years who gave birth to their first child were recruited between 43 and 60 days after delivery. Seroprevalence was performed using a type-specific enzyme-linked immunosorbent assay based on HPV Late protein 1 viruslike particles. The association of seroreactivity with these 4 HPV types with selected demographic and behavioral factors was assessed by Generalized Linear Model analysis. Results: Fifty-eight (19.3%) women (95% confidence interval, 15.0%-24.2%) had antibodies to any of the 4 viruslike particles tested. The overall seroprevalence rates of the HPV types were: HPV16, 9.0%; HPV18, 7.0%; and HPV 6+11, 7.7%, which are targeted by the HPV prophylactic vaccines. In the multivariate analysis, only age (inversely, P = 0.044 for trend) and previous sexually transmitted disease (P = 0.008) were 2 factors independently associated with HPV seropositivity. Conclusions: These data offer additional information on the epidemiology of HPV in a group of young Brazilian women after first delivery and contribute to establish a baseline of HPV seroprevalence against which post-HPV vaccine era seroprevalence can be compared.
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The Leishmune (R) vaccine has been used in endemic areas to prevent canine visceral leishmaniasis in Brazil, but cytokine production induced by vaccination has rarely been investigated in dogs. This study aimed to evaluate the immune response of dogs vaccinated with Leishmune FML vaccine (Fort Dodge) against total antigen of Leishmania (Leishmania) chagasi (TAg) and FML. Twenty healthy dogs from Aracatuba, Sao Paulo, Brazil, an endemic leishmaniasis area, received three consecutive subcutaneous injection of Leishmune vaccine at 21-day intervals. PBMC were isolated before and 10 days after completing vaccination and lymphoproliferative response and antibody production against FML or total promastigote antigen were tested. Cytokines IFN-gamma, IL-4 and TNF-alpha were measured in culture supernatant and CD4+/CD25+ and CD8+/CD25+ T cell presence was determined. Analysis of the data indicated that the vaccine conferred humoral responses (100%) against both antigens and cellular immunity to FML (85%) and total antigen (80%), the supernatant of cultured cells stimulated with TAg and FML showed an increase in IFN-gamma (P < 0.05), and the vaccine reduced CD4+/CD25+ T cell presence compared to that observed before vaccination. These responses may constitute part of the immune mechanism induced by Leishmune. (C) 2010 Elsevier B.V. All rights reserved.
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Objective. To study the epidemiology of rotavirus and estimate rotavirus- associated morbidity and mortality in children <= 5 years of age in Brazil in 2004 before introducing the rotavirus vaccine in Brazil`s National Immunization Program ( Programa Nacional de Imunizacoes, PNI). Methods. To estimate rotavirus morbidity, published studies ( 1999 - 2006) addressing incidence of acute diarrhea among children <= 5 years of age and frequency of rotavirus infection among children with diarrhea in Brazil were reviewed. Diarrhea episodes were divided into three categories of severity by level of care: mild cases requiring only home- based care; moderate cases requiring a visit to an outpatient healthcare facility; and severe cases requiring hospitalization. To estimate rotavirus mortality, information on the number of registered deaths from diarrhea in children <= 5 years of age was obtained from the Mortality Information System ( Sistema de Informacao, sobre Mortalidade, SIM) of Brazil`s public healthcare system ( Sistema Unico de Sa de, SUS) and the proportion of deaths due to rotavirus was calculated. Results. Rotavirus infections were estimated to cause 3 525 053 episodes of diarrhea, 655 853 visits to outpatient healthcare facilities, 92 453 hospitalizations, and 850 deaths of children <= 5 years of age each year in Brazil. Conclusion. Rotavirus infections are an important cause of child morbidity and mortality in Brazil.
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Background: Worldwide strategies have been conducted in order to guarantee longer periods of exclusive breastfeeding for most children, especially those from developing countries. The evaluation of infant feeding practices and the identification of weaning risk factors are essential for public health policy planning. Methods: This cross-sectional study was carried out in Joinville, the biggest city of Santa Catarina State in the southern Brazilian region. The caregivers of children under 1 year of age were systematically selected for interview in previously drawn immunization units during the 2005 National Vaccination Campaign. A structured questionnaire was applied for collection of infant, maternal, and healthcare variables. A 24-hour food recall survey was included in order to evaluate infant feeding practices. Descriptive statistic analysis on breastfeeding prevalence and Poisson regression analysis of risk factors for discontinuing exclusive breastfeeding for infants up to 6 months of age were performed. Results: Caregivers of 1,470 infants were interviewed. The feeding inquiry showed an overall rate of breastfeeding of 72.5% and a frequency of exclusive breastfeeding of 43.7% and 53.9% among infants younger than 6 and 4 months of age, respectively. The findings associated with the interruption of exclusive breastfeeding for infants up to 6 months were: higher infant age (P < 0.001), pacifier use (P < 0.001), and lower maternal educational level (P = 0.013). Conclusions: In developing countries, specific strategies must be created for the delivery of information about breastfeeding and the effect of pacifier use, especially for less educated women.
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Whether gestational immunization of HIV-infected mothers with the 23-valent pneumococcal polysaccharide vaccine (PPV) confers maternal and infant early life, passive protection is not known. We evaluated safety, immunogenicity and placental transfer of antibodies in 44 HIV-infected women. Pneumococcal IgG antibodies against serotypes 1, 3, 5, 613, 9V, and 14 were measured in mothers (pre-vaccination and at delivery), and infants (at birth, 1, 2, 3, and 6 months). PPV was safe and immunogenic in mothers. Newborns received 46-72% of maternal antibody titers. Overall, infants had antibody levels lower than protective by 2 months of age. Alternative pneumococcal vaccination of HIV-infected pregnant women should be explored with the aim of prolonging passive protection in their infants. (C) 2009 Elsevier Ltd. All rights reserved.