Suicide attempts among children and adolescents: partial or total injury? / Tentativa de suicídio infanto-juvenil: lesão da parte ou do todo?

This study sought to verify the records on file and the number of cases of attempted suicide among children and adolescents who were attended by Emergency Care health professionals in the municipality of Matozinhos, Minas Gerais, Brazil. Documentary and descriptive research was conducted, the data for which was collected by means of an investigation of Outpatient Records from 2008 to 2010. Of the 73,000 files evaluated, those dealing with cases of attempted suicide among children and adolescents between the age of 3 and 18 years were selected. It was revealed that the health professionals, particularly physicians and nurses, fail to register the cases appropriately, invalidating information about the problem and potential prevention measures. The conclusion reached was that underreporting and the discrepancy of the diagnoses which were not duly referred to the competent agencies require rethinking and reviewing medical practices, and taking a systematic and careful look to address the individual as a complex whole.

Neste estudo procurou-se verificar o registro e o número de casos de tentativa de suicídio entre crianças e adolescentes do município de Matozinhos, Minas Gerais, Brasil, que foram atendidos pelos profissionais de saúde do Pronto-Atendimento. Trata-se de uma pesquisa documental e descritiva, cuja coleta dos dados ocorreu por meio de investigação nas Fichas Ambulatoriais, no período de 2008 a 2010. Das 73.000 fichas levantadas, selecionaram-se aquelas que tratavam de casos de tentativa de suicídio entre crianças e adolescentes do município, com idades entre três e 18 anos. Percebeu-se que os profissionais de saúde, mais especificamente os médicos e enfermeiros, não registram os casos de forma adequada, inviabilizando a informação sobre o problema e as medidas de prevenção. Concluiu-se que a subnotificação, a discrepância dos diagnósticos e o não encaminhamento aos órgãos competentes exigem repensar e rever a prática médica e dirigir um olhar sistematizado e cuidadoso para perceber o sujeito como um todo complexo.

Probing the specifics of substrate binding for cytochrome c oxidase: a computer assisted approach / Investigación de las especifidades de la unión de substrato para la citocromo-c-oxidasa: un enfoque asistido por computadora

A deficiency of cytochrome c oxidase (COX) is associated with a number of diseases but details of the enzyme's mechanism of action especially the interaction with its substrate, ferrocytochrome c, remain unclear. It is known that the transfer of electrons from ferrocytochrome c to COX is facilitated by the formation of enzyme-substrate (ES) complexes which are stabilized by intermolecular salt bridges, however the identity of residues participating in the salt bridges remains obscure. Using the published structures of the two proteins, computer simulations were employed to model their interactions and to attempt to identify residues that participate in intermolecular salt bridges. The simulation process was guided in the main by cross-linking studies which proposed that Lys-13 of cytochrome c is paired with Asp-158 of COX. The initial enzyme-substrate complex, created by computer assisted manipulation of the two structures exhibited three salt bridges; following the application of energy minimization procedures, the number of salt bridges increased to seven and there were twenty-four intermolecular hydrogen bonds. The salt bridges emanated from: Glu-119 and Asp-221 of subunit I; Glu-114, Asp-115 and Asp-158 of subunit II and Asp-73 and Glu-78 of subunit VIb. These were paired with Lys-87, 8, 25, 27, 13, 22 and 100 respectively of cytochrome c. These results suggest that subunits I, II and VIb play direct roles in substrate binding. The results also suggest that hydrogen bonds contribute significantly to the stability of the ES-complex.

La deficiencia de la citocromo-c-oxidasa (COX) se halla asociada con un número de enfermedades, pero los detalles del mecanismo de acción - especialmente la interacción con su substrato, el ferrocitocromo c - no está aún claro. Se sabe que la transferencia de electrones del ferrocitocromo c a la COX, es facilitada por la formación de los complejos enzima-substrato (ES), los cuales son estabilizados por puentes intermoleculares de sal. No obstante, la identidad de los residuos que participan en los puentes sigue sin estar clara. Recurriendo a las estructuras publicadas de dos proteínas, se emplearon simulaciones por computadora a fin de obtener un modelo de sus interacciones, en un intento por identificar los residuos que toman parte en los puentes de sal. El proceso de simulación fue guiado principalmente por estudios de reticulación, que proponen que el Lys-13 del citocromo c está pareado con el Asp-18 de la COX. El complejo enzima-sustrato inicial creado mediante la manipulación asistida por computadora de las dos estructuras, exhibía tres puentes de sal. Tras aplicar los procedimientos de minimización de la energía, el número de puentes de sal aumentó a siete y hubo veinticuatro enlaces intermoleculares de hidrógeno. Los puentes de sal emanaron de: Glu-119 y Asp-221 de la subunidad I; Glu-114, Asp-115 y Asp-158 de la subunidad II y Asp-73 y Glu-78 de la subunidad VIb. Estos fueron pareados con Lys-87, 8, 25, 27, 13, 22 y 100 respectivamente del citocromo c. Estos resultados sugieren que las subunidades I, II y VIb juegan un papel directo en la unión del substrato. Los resultados también sugieren que los enlaces de hidrógeno contribuyen significativamente a la estabilidad del complejo-ES.

Polaron hopping in some biomolecular solids and their charge transfer complexes.

The solid state spectroscopy of charge transfer complexes of biomolecules such as fatty acids, tripalmitin, lysozyme. folic acid, beta-carotene, cytochrome c, valinomycin and gramicidin has been carried out. The absorption coefficient is related with electronic conductivity. A half-power beta density is found common among these macromolecular solids, indicating photon-induced polaron hopping or hopping of a charge carrier between two branches of a polariton. Band gap vs full width at half-maximum of the mid-IR peak also reveals a linear relation.

Kinetics and mechanism of reduction of ferricytochrome c by glutathione and L-cysteine: a comparative study.

The kinetics and mechanism of the reduction of ferricytochrome c [Cyt c(III)] by substrates namely glutathione (GSH) and L-cysteine (L-cys) have been investigated spectrophotometrically employing [substrate]T > [Cyt c(III)]T. The reaction exhibits first order dependence in [substrate]T and [Cyt c(III)]T. The pseudo-first order rate constant increases with an increase in pH, indicating that the conjugate base form of the HCyt c(III) is a better oxidant than the parent HCyt c(III). The electron transfer rate constants between the oxidants and GSH for both the k1 and k2 paths are found to be greater than that with L-cysteine. Hence, GSH is a better reductant of Cyt c(III) as compared to L-cysteine. A suitable mechanism has been proposed on the basis of experimental findings. The deprotonation constant for HCyt c(III) and the second order rate constants of k1 and k2 paths for the present reaction at 25 degrees C have been determined.