4 resultados para Jahnke, Fred

em DigitalCommons@The Texas Medical Center


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Operant conditioning is a ubiquitous but mechanistically poorly understood form of associative learning in which an animal learns the consequences of its behavior. Using a single-cell analog of operant conditioning in neuron B51 of Aplysia, we examined second-messenger pathways engaged by activity and reward and how they may provide a biochemical association underlying operant learning. Conditioning was blocked by Rp-cAMP, a peptide inhibitor of PKA, a PKC inhibitor, and by expressing a dominant-negative isoform of Ca2+-dependent PKC (apl-I). Thus, both PKA and PKC were necessary for operant conditioning. Injection of cAMP into B51 mimicked the effects of operant conditioning. Activation of PKC also mimicked conditioning but was dependent on both cAMP and PKA, suggesting that PKC acted at some point upstream of PKA activation. Our results demonstrate how these molecules can interact to mediate operant conditioning in an individual neuron important for the expression of the conditioned behavior.

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The approach to the diagnosis and treatment of congenital toxoplasmosis has been one of flux and debate, fueled by lack of knowledge, lack of consensus, different methods of screening and different national policies for screening in different parts of the world. Countries with higher prevalence of disease such as in Europe and South America have a heightened awareness of the need to screen and treat for this parasitic infection during pregnancy. In contrast, in the United States, it is a condition scarcely discussed and has been largely ignored except in some large centers and by a few researchers. Policies and research strategies for any condition should start with obtaining good data. The aims of this thesis included a review of prevalence studies conducted in the United States, focused on the past 20 years, combined with a description of original research conducted by the author several years ago. The latter was a cross-sectional study performed in Houston, one of the largest American cities with a great ethnic mix. The study analyzed prevalence rates of Toxoplasma gondii IgG antibody in sera of women of reproductive age. Overall seroprevalence was 12.3%. In keeping with other studies, higher prevalence correlated with lower socioeconomic status, Black and Hispanic and Asian ethnicities, and increasing age. A literature search revealed only three prevalence studies performed in the United States over the past 20 years, with another four studies only referred to as personal communications or within a textbook, without further study detail available. The literature review also revealed a lack of consensus on whether or not to screen for toxoplasmosis in pregnancy, and even whether or not treatment in utero is worthwhile.^ Proponents of screening and treatment in pregnancy site studies both in the United States and France, emphasize that treatment reduces disease manifestations in infants. Opponents cite other studies that show only marginal benefits, together with potential side effects of medication regimens and generation of anxiety in parents. What is agreed on so far is the value of educating pregnant women on how to avoid contracting toxoplasmosis, and educating physicians on making the best use of reference laboratories before major treatment decisions are made. Further research to reevaluate the literature critically, review new treatment regimens and examine costs and benefits of screening and treatment of toxoplasmosis in pregnancy, bringing together European and American researchers, is needed.^

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Developing countries suffer from an array of diseases, of which the developed world is unfamiliar. In order to facilitate the development of community interventions and streamline NGO partnership, needs assessments in targeted areas are conducted. The purpose of this assessment was to attain baseline descriptive data to further understand the needs of the village of Robit, Ethiopia. A trained team collected data from Austin based non-profit Water to Thrive (W2T) on June 1st and 2nd, 2011 through focus groups, key informant interviews, and individual surveys. Qualitative and quantitative data were paired to affirm the results of one another through triangulation. The results identified an apparent need for health intervention and education. Malaria, water-borne disease, respiratory issues (asthma, Upper respiratory tract infections), and maternal and child health were among the evident problems in Robit. There was a clear need for midwife training as well as water sanitation, latrine building, and general illness treatment. Poor road conditions and annual flooding of Robit plays an important role in the poor health and lack of food security of the village. While some evidence of social desirability and recall bias was found in the interview and survey data, the triangulation of findings provided important insights and validity to the needs assessment. ^