Stable isotope dilution analysis of orotic acid and uracil in amniotic fluid

Rapid, sensitive and accurate stable isotope dilution assays were developed for the measurement of orotic acid and uracil in amniotic fluid. The method utilizes [15N2]orotic acid and [15N2]uracil as internal standards, isolation by liquid partition chromatography and quantitation by chemical ionization selected ion monitoring gas chromatography-mass spectrometry. Orotic acid at a concentration of 0.26 ± 0.05 μmol/1 and uracil at a concentration of 0.55 ± 0.13 μmol/l were detectable in normal amniotic fluid. As affected fetuses with argininosuccinate synthetase or ornithine carbamoyl transferase deficiency showed no significant elevation of orotic acid and/or uracil in their surrounding amniotic fluids, this method unfortunately seemed not to be useful for prenatal diagnosis of these inherited disorders. Nevertheless, it provides significant advantage over available methods for the quantitation of orotic acid and uracil in which the analysis of these compounds must be very accurate, highly specific and sensitive (e.g. detection of heterozygosity for omithine carbamoyl transferase deficiency)

4-aminobutyrate aminotransferase (GABA-transaminase) deficiency

A entrevista de testemunhas é um procedimento fundamental no decurso das investigações policiais e avaliações forenses. No entanto, o conhecimento, formação e treino destes profissionais para entrevistar testemunhas é frequentemente insuficiente, levando ao uso de técnicas de entrevista inadequadas e à obtenção de informação limitada e pouco fidedigna. Neste artigo abordamos a Entrevista Cognitiva Melhorada, atualmente aceite como um dos métodos mais eficazes para obter bons testemunhos. Descrevemos pormenorizadamente esta entrevista, quais os pressupostos teóricos que justificam a sua utilização, incidindo ainda sobre a investigação relevante. Por fim, elaboramos um guia de utilização para esta entrevista baseado nos resultados da investigação e no modelo utilizado pelas forças policiais de Inglaterra e Gales (i.e. “PEACE”). Não existindo nenhum outro protocolo publicado em língua portuguesa para a aplicação da Entrevista Cognitiva Melhorada, consideramos a leitura deste artigo um primeiro passo para todos os profissionais que pretendam utilizar este modelo de entrevista

Delineation of the motor disorder of Lesch-Nyhan disease.

Contains fulltext : 51161.pdf (publisher's version ) (Open Access)Lesch-Nyhan disease (LND) is caused by deficiency of the purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). Affected individuals exhibit over-production of uric acid, along with a characteristic neurobehavioural syndrome that includes mental retardation, recurrent self-injurious behaviour and motor disability. Prior studies involving relatively small numbers of patients have provided different conclusions on the nature of the motor disorder. The current study includes the results of a multi-centre international prospective study of the motor disorder in the largest cohort of patients studied to date. A total of 44 patients ranging from 2 to 38 years presented a characteristic motor syndrome that involved severe action dystonia superimposed on baseline hypotonia. Although some patients also displayed other extrapyramidal or pyramidal signs, these were always less prominent than dystonia. These results are compared with a comprehensive review of 122 prior reports that included a total of 254 patients. Explanations for the differing observations available in the literature are provided, along with a summary of how the motor disorder of LND relates to current understanding of its pathophysiology involving the basal ganglia

Equilibrium and Adverse Selection

The nature of equilibrium in markets with adverse selection evoked considerable interest following George Akerlof's famous paper on the market for lemons. Whereas Akerlof argued that markets with adverse selection may yield no equilibrium, Charles Wilson has argued that multiple equilibria may result. In this paper, it is shown that if the distribution of quality follows some standard distribution, then a unique equilibrium will result. In the (less plausible) context of multiple-equilibria, conditions are derived under which both buyers and sellers will prefer higher price-equilibria