ABSTRACT
The occurrence of a weak auditory warning stimulus increases the speed of the response to a subsequent visual target stimulus that must be identified. This facilitatory effect has been attributed to the temporal expectancy automatically induced by the warning stimulus. It has not been determined whether this results from a modulation of the stimulus identification process, the response selection process or both. The present study examined these possibilities. A group of 12 young adults performed a reaction time location identification task and another group of 12 young adults performed a reaction time shape identification task. A visual target stimulus was presented 1850 to 2350 ms plus a fixed interval (50, 100, 200, 400, 800, or 1600 ms, depending on the block) after the appearance of a fixation point, on its left or right side, above or below a virtual horizontal line passing through it. In half of the trials, a weak auditory warning stimulus (S1) appeared 50, 100, 200, 400, 800, or 1600 ms (according to the block) before the target stimulus (S2). Twelve trials were run for each condition. The S1 produced a facilitatory effect for the 200, 400, 800, and 1600 ms stimulus onset asynchronies (SOA) in the case of the side stimulus-response (S-R) corresponding condition, and for the 100 and 400 ms SOA in the case of the side S-R non-corresponding condition. Since these two conditions differ mainly by their response selection requirements, it is reasonable to conclude that automatic temporal expectancy influences the response selection process.
Subject(s)
Adult , Female , Humans , Male , Young Adult , Attention/physiology , Pattern Recognition, Visual/physiology , Photic Stimulation/methods , Reaction Time/physiology , Acoustic Stimulation/methodsABSTRACT
Óleos essenciais de plantas têm sido formulados de forma caseira ou colocados no mercado de forma artesanal para repelir mosquitos hematófagos. O presente trabalho avaliou o possível efeito repelente de alguns excipientes normalmente usados em formulações comerciais e de óleos essenciais de nove plantas, sobre fêmeas de Aedes albopictus. Os testes foram realizados em caixas contendo mosquitos, oferecendo-se uma área definida de dedos da mão tratados ou não. Exceto pelo creme Lanatte e os géis de carbopol, as substâncias excipientes avaliadas mostraram ação repelente. Apenas os óleos provenientes de citronela (5 e 10 por cento) resultaram em repelência expressiva, com índices médiosde proteção acimade 98 por cento. Os resultados indicam que a metodologia empregada é adequada para a avaliação preliminar de produtos com potencial para a repelência de mosquitos.
Plant essential oils have been domestically formulated or marketed as handcraft products to repel hematophagous mosquitoes. This work evaluated the possible repellent effect of both excipients normally used in commercial formulations and essential oils from nine plants against Aedes albopictus females. The assays were carried out in boxes containing mosquitoes, where a defined area of treated or non-treated fingers was offered. Except for Lanatte cream and carbopol gels, the evaluated excipients had repellent action. Only the oils from citronella (5 and 10 percent) presented expressive repellent action, with mean protection indexes above 98 percent. The results indicate that the used methodology is appropriate for the preliminary evaluation of products with potential to repel mosquitoes.
Subject(s)
Culicidae , Diptera , Plant Extracts/analysis , Insect Repellents , Oils, Volatile/analysis , Biological Assay , Cymbopogon/toxicity , Plant StructuresABSTRACT
Objetivou-se com o presente estudo avaliar a influência da temperatura de armazenamento e do sistema de utilização do tanque de refrigeração sobre a qualidade microbiológica do leite cru. Foram analisadas 1.215 amostras quanto a contagem bacteriana total (CBT), através da metodologia de citometria de fluxo. Nas amostras abaixo de 4,0ºC , entre 4,1 e 7,0ºC e acima de 7,0ºC a CBT média foi 2.733.000 UFC / ml, 3.641.000 UFC / ml e 5.687.000 UFC / ml, respectivamente. A CBT média das amostras provenientes de tanques coletivos foi 5.536.000 UFC / ml e das colhidas em tanques individuais foi 2.604.000 UFC / ml, sendo significativamente diferente (p<0,05). Observou-se que 70,21 por cento das amostras analisadas apresentaram CBT abaixo de 1.000.000 de UFC / ml. A baixa qualidade microbiológica das amostras sugere predominantemente a ocorrência de falhas na higiene de ordenha.
Subject(s)
Food Preservation , Milk , TemperatureABSTRACT
Organ transplantation can be considered as replacement therapy for patients with end-stage organ failure. The percent of one-year allograft survival has increased due, among other factors, to a better understanding of the rejection process and new immunosuppressive drugs. Immunosuppressive therapy used in transplantation prevents activation and proliferation of alloreactive T lymphocytes, although not fully preventing chronic rejection. Recognition by recipient T cells of alloantigens expressed by donor tissues initiates immune destruction of allogeneic transplants. However, there is controversy concerning the relative contribution of CD4+ and CD8+ T cells to allograft rejection. Some animal models indicate that there is an absolute requirement for CD4+ T cells in allogeneic rejection, whereas in others CD4-depleted mice reject certain types of allografts. Moreover, there is evidence that CD8+ T cells are more resistant to immunotherapy and tolerance induction protocols. An intense focal infiltration of mainly CD8+CTLA4+ T lymphocytes during kidney rejection has been described in patients. This suggests that CD8+ T cells could escape from immunosuppression and participate in the rejection process. Our group is primarily interested in the immune mechanisms involved in allograft rejection. Thus, we believe that a better understanding of the role of CD8+ T cells in allograft rejection could indicate new targets for immunotherapy in transplantation. Therefore, the objective of the present review was to focus on the role of the CD8+ T cell population in the rejection of allogeneic tissue
Subject(s)
Animals , Humans , CD4-Positive T-Lymphocytes , CD8-Positive T-Lymphocytes , Graft Rejection , Graft Survival , Immunosuppressive Agents , CD4-Positive T-Lymphocytes , CD8-Positive T-Lymphocytes , Cell Differentiation , Chemokines , Cytokines , Graft Rejection , Graft Survival , Transplantation, HomologousSubject(s)
Humans , Dogs , Cricetinae , Mice , Rabbits , Rats , In Vitro Techniques , Graft Rejection/immunology , Transplantation Immunology/immunology , Transplantation, Heterologous/immunology , Antibody Formation , Species Specificity , Haplorhini , Immunity, Cellular , Immunosuppression Therapy , Pan troglodytes , Swine , Transplantation, Heterologous/trendsABSTRACT
A farmacocinética da ciclosporina demosntra grande variaçäo inter e intra-individual e profundas mudanças säo, freqüentemente, observadas após o transplante renal. OBJETIVO. analisar seriadamente a farmacocinética da ciclosporina e de seus metabólitos através da determinaçäo de sua concentraçäo sanguínea, em pacientes submetidos a transplante renal. MÉTODOS. Foram realizados 70 estudos em 29 pacientes, sendo 26 antes e 44 após o transplante renal. Em cada estudo a curva de absorçäo foi analisada mediante a determinaçäo da concentraçäo sanguínea da ciclosporina, utilizando radioimunoensaio com anticorpos monoclonais específicos (RIE-MoSP) e inespecíficos (RIE-MoNP), em 17 amostras colhidas após a sua administraçäo oral ou endovenosa (0; 0,5; 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 12; 16; 20; 23; 24h). Resultados. A área sob a curva da concentraçäo sanguínea de ciclosporina em funçäo do tempo (AUC), a biodisponibilidade (F), a concentraçäo máxima (Cmax) e as concentraçöes sanguíneas obtidas 12 e 24 horas após a sua administraçäo (C12 e C24), determinadas com RIE-MoSP, foram inferiores àquelas encontradas com RIE-MoNP, enquanto a depuraçäo (CL) e o volume de distribuiçäo (Vd) foram maiores. A meia-vida de eliminaçäo foi semelhante utilizando os dois métodos (t1/2). A absorçäo seguiu uma cinética de ordem zero, sendo observada uma correlaçäo inversa entre a dose de ciclosporina e a AUC/dose (r = 0,55, RIE-MoSP e r = 0,42, RIE-MoNP). A fraçäo de absorçäo (F) variou entre 18 por cento e 68 por cento (RIE-MoSP), sendo superestimada quando determinada com RIE-MoNP (38 por cento a 100 por cento), conseqüência da extensa metabolizaçäo na primeira passagem pelo intestino e fígado...