The achievement of boar sperm in vitro capacitation is related to an increase of disrupted disulphide bonds and intracellular reactive oxygen species levels.

The aim of this work was to determine the relationship of intracellular reactive oxygen species (ROS) and the disulphide bonds established between sperm proteins with the achievement of capacitation in boar spermatozoa. With this purpose, spermatozoa were incubated in a specifically designed in vitro capacitation medium (CM) in the presence or absence of reduced glutathione (GSH). Incubation of boar spermatozoa in CM for 4 h significantly (p < 0.05) increased free cysteine residues, which is a marker of disrupted disulphide bonds, and also intracellular ROS levels. The addition of GSH to the medium prevented most capacitation-like changes in sperm motility, membrane lipid disorder, mitochondrial membrane potential, intracellular calcium levels and localization of tyrosine-phosphorylated proteins (pTyr), but not in tyrosine phosphorylation of P32. These effects were accompanied by the inhibition of the ability of sperm cells to trigger the acrosome exocytosis in response to progesterone. When GSH was added together with progesterone after 4 h of incubation, acrosome exocytosis was not altered, but the subsequent decrease in intracellular calcium observed in controls cells was inhibited. Furthermore, co-incubation of oocytes with spermatozoa previously incubated in CM in the presence of GSH for 4 h significantly (p < 0.05) increased the number of spermatozoa attached to the oocyte surface but decreased normal fertilization rates. Our results suggest that boar sperm capacitation is related to an increase in disrupted disulphide bonds and intracellular ROS levels and that both events are related to the regulation of hyperactivated motility, intracellular calcium dynamics, sperm binding ability to the oocyte and achievement of proper nuclear decondensation upon oocyte penetration.

Seguridad en Anestesia. Un checklist entre los Anestesiólogos en Chile / Safety in Anesthesia. A checklist of Anesthesiologists in Chile

Aim: To describe the knowledge of the country's anesthesiologists about perioperative safety protocols in order to contribute information to the discussion of a general system for the registration and analysis of incidents as part of the implementation of the Helsinki Declaration on Patient Safety in Chile. Materials and Methods: The information was obtained through 100 surveys sent anonymously to members of the Chilean Society of Anesthesiology, which were answered voluntarily. Results: 89 anesthesiologists responded to the survey. 30% are familiar with the Helsinki Declaration. The most established protocols in their clinical centers were infection control (78%), malignant hyperthermia (72%) and drug monitoring (70%). By contrast, the protocols for massive hemorrhage, local anesthetic toxicity and anaphylaxis are observed to a lesser degree. The inclusion of an annual report on mortality and morbidity was recorded in 35% and an annual report on measures taken and outcomes obtained in the improvement of patient safety was only 23%. Conclusions: A low level of knowledge of the Helsinki Declaration is found among the anesthesiologists of the SACH. Not all its protocols are widely implemented, which makes it necessary to develop a policy to assess the development and impact of this Declaration in Chile. It is urgent to strengthen a national registration system to correct behaviors and thus strengthen perioperative safety to the benefit of our patients.

Objetivo: Describir el conocimiento de los anestesiólogos del país acerca de los protocolos de seguridad perioperatorios, para aportar información en la discusión de un sistema general de registro y análisis de incidentes, en el marco de la implementación de la declaración de Helsinki sobre la seguridad del paciente en nuestro país. Material y Método: La información se obtuvo a través de 100 encuestas enviadas de anónimamente a miembros de la sociedad chilena de anestesiología, la que fue respondida de forma voluntaria. Resultados: Contestaron la encuesta 89 anestesiólogos. Un 30% conoce la Declaración de Helsinki. Los protocolos más establecidos en sus centros clínicos fueron el control de infecciones (78%) Hipertermia maligna (72%) y control de fármacos (70%). Al contrario, los protocolos de hemorragia masiva, intoxicación por anestésicos locales y anafilaxia se observan en menor porcentaje. La realización de un informe anual de mortalidad y morbilidad se consignó en un 35% y un reporte anual de medidas tomadas y de resultados obtenidos en la mejora de la seguridad del paciente fue de sólo un 23%. Conclusiones: Se observa un bajo nivel de conocimiento de la declaración de Helsinki entre los anestesiólogos de la SACH. No todos sus protocolos están ampliamente implementados, lo que se hace necesario desarrollar una política de evaluación del desarrollo e impacto de esta declaración en nuestro país. Es imperioso fortalecer un sistema nacional de registro para corregir conductas, y de esta forma fortalecer la seguridad en el perioperatorio en beneficio de nuestros pacientes.

Geometry-dependent DNA-TiO2 immobilization mechanism: A spectroscopic approach.

DNA nucleotides are used as a molecular recognition system on electrodes modified to be applied in the detection of various diseases, but immobilization mechanisms, as well as, charge transfers are not satisfactorily described in the literature. An electrochemical and spectroscopic study was carried out to characterize the molecular groups involved in the direct immobilization of DNA structures on the surface of nanostructured TiO2 with the aim of evaluating the influence of the geometrical aspects. X-ray photoelectron spectroscopy at O1s and P2p core levels indicate that immobilization of DNA samples occurs through covalent (POTi) bonds. X-ray absorption spectra at the Ti2p edge reinforce this conclusion. A new species at 138.5eV was reported from P2p XPS spectra analysis which plays an important role in DNA-TiO2 immobilization. The POTi/OTi ratio showed that quantitatively the DNA immobilization mechanism is dependent on their geometry, becoming more efficient for plasmid ds-DNA structures than for PCR ds-DNA structures. The analysis of photoabsorption spectra at C1s edge revealed that the molecular groups that participate in the C1s→LUMO electronic transitions have different pathways in the charge transfer processes at the DNA-TiO2 interface. Our results may contribute to additional studies of immobilization mechanisms understanding the influence of the geometry of different DNA molecules on nanostructured semiconductor and possible impact to the charge transfer processes with application in biosensors or aptamers.

¿Es útil el ejercicio en la prevención de infecciones respiratorias altas? / Is the exercise effective for the prevention of upper respiratory tract infections?

INTRODUCCIÓN: Las infecciones respiratorias altas son una de las principales causas de consulta médica en el mundo. Dado que no hay tratamiento específico, la prevención es fundamental. Se ha postulado que el ejercicio tendría un rol preventivo, pero su real efectividad sigue siendo motivo de controversia. MÉTODOS: Para responder a esta pregunta, utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos tablas de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos cuatro revisiones sistemáticas, que en conjunto incluyeron 14 estudios primarios, de los cuales seis corresponden a ensayos aleatorizados. Concluimos que aún no está claro si el ejercicio físico de moderada intensidad previene o no las infecciones respiratorias altas, porque la certeza de la evidencia existente es muy baja.

INTRODUCTION: Upper respiratory tract infections are one of the main causes of medical consultation in the world. Considering the lack of specific treatment, prevention becomes essential. It has been postulated that exercise could have a preventive role, but its clinical effectiveness remains a topic of discussion. METHODS: To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified four systematic reviews including fourteen studies overall, of which six were randomized trials. We concluded it is not clear whether exercise of moderate intensity prevents or not upper respiratory infections, because the certainty of the evidence is very low.

¿Es efectivo el tratamiento con células madre en la enfermedad de Parkinson? / Is treatment with stem cells effective in Parkinson's disease?

Resumen INTRODUCCIÓN: Muchos pacientes con enfermedad de Parkinson tienen una respuesta limitada con el tratamiento farmacológico convencional. Se ha postulado el uso de células madre como una alternativa, aunque su efectividad sigue siendo un tema de controversia. MÉTODOS: Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos dos revisiones sistemáticas que en conjunto incluyeron 21 estudios primarios, de los cuales tres corresponden a ensayos aleatorizados. Concluimos que no está claro si las células madre podrían tener algún efecto sobre la sintomatología de la enfermedad de Parkinson porque la certeza de la evidencia disponible es muy baja.

Abstract INTRODUCTION: There are many patients with Parkinson's disease who have a limited response to conventional pharmacological treatment. The use of stem cells has been postulated as an alternative, although its effectiveness remains a matter of controversy. METHODS: To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified two systematic reviews including 21 studies overall, of which three were randomized trials. We concluded it is not clear whether stem cells have any effect on the symptoms of Parkinson's disease because the certainty of the available evidence is very low.

Non-thermal ion desorption from an acetonitrile (CH3CN) astrophysical ice analogue studied by electron stimulated ion desorption.

The incidence of high-energy radiation onto icy surfaces constitutes an important route for leading new neutral or ionized molecular species back to the gas phase in interstellar and circumstellar environments, especially where thermal desorption is negligible. In order to simulate such processes, an acetonitrile ice (CH3CN) frozen at 120 K is bombarded by high energy electrons, and the desorbing positive ions are analyzed by time-of-flight mass spectrometry (TOF-MS). Several fragment and cluster ions were identified, including the Hn=1-3(+), CHn=0-3(+)/NHn=0-1(+); C2Hn=0-3(+)/CHn=0-3N(+), C2Hn=0-6N(+) ion series and the ion clusters (CH3CN)n=1-2(+) and (CH3CN)n=1-2H(+). The energy dependence on the positive ion desorption yield indicates that ion desorption is initiated by Coulomb explosion following Auger electronic decay. The results presented here suggest that non-thermal desorption processes, such as desorption induced by electronic transitions (DIET) may be responsible for delivering neutral and ionic fragments from simple nitrile-bearing ices to the gas-phase, contributing to the production of more complex molecules. The derived desorption yields per electron impact may contribute to chemical evolution models in different cold astrophysical objects, especially where the abundance of CH3CN is expected to be high.

Electronic relaxation effects in condensed polyacenes: A high-resolution photoemission study.

We present a high-resolution photoelectron spectroscopy investigation of condensed films of benzene, naphthalene, anthracene, tetracene, and pentacene. High spectroscopic resolution and a systematic variation of the molecular size allow a detailed analysis of the fine structures. The line shapes of the C 1s main lines are analyzed with respect to the different contributions of inhomogeneous broadening, vibronic coupling, and chemical shifts. The shake-up satellite spectra reveal trends, which give insight into the charge redistribution within the molecule upon photoexcitation. In particular, the shake-up between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) increases in intensity and moves closer toward the C 1s main line if the size of the aromatic system is increased. An explanation is given on the basis of the delocalization of the aromatic system and its capability in screening the photogenerated core hole. A comparison of the HOMO-LUMO shake-up position to the optical band gap gives additional insight into the reorganization of the electronic system upon photoexcitation.

Identificación de los determinantes de la estadía en unidades de cuidados intensivos usando redes neuronales artificiales / Prediction of the length of stay in intensive care units using artificial neural networks

Background: The prediction of the length of stay at the moment of hospital admission is of outmost importance. Many studies have used lineal models to predict this variable, but there are inherent limitations to these models. The use of non lineal models has been scarce. Aim: To develop a non lineal model to predict length of stay in intensive care units. Material and methods: Retrospective analysis of 294 patients admitted to two intensive care units in Santiago, Chile. The severity of the disease motivating the admission was nominally quantified. This and other physiological variables were included in the model. The length of stay was modeled using Artificial Neural Networks. Results: The model yielded an error of 8.7 percent (3.6 ñ 0.4 days, CI 95 percent) and a correlation coefficient of 0.9 (p <0.001) for the prediction of length of stay. Using net sensitivity analysis, the model determined that gastrointestinal diseases, infections and respiratory problems were the main causes of prolongation of intensive care unit stay. Conclusions: Intensive care units should have, in the future, computer systems that gather vital information to predict length of stay

Cáncer de vejiga: tabaco como factor de riesgo / Bladder cancer: tobacco like risk factors

Entre setiembre de 1997 y marzo de 1998 se diagnosticaron y trataron en nuestro servicio 45 pacientes con cáncer de vejiga, de los cuales 41 casos fueron carcinomas superficiales, 3 infiltrantes y el restante carcinoma "in situ". El objetiv o del presente trabajo fue observar cuáles eran los factores de riesgo para el desarrollo de esta neoplasia. Se detectó que en el 85 por ciento de estos pacientes el hábito de fumar se encontraba presente (p<0,01), determinándose además la relación entre la cantidad de cigarrillos consumidos por día y el grado de diferenciación celular. Se registró también que los pacientes que fumaban tabaco negro desarrollaron tumores de mayor estadio de infiltración. En los restantes pacientes los factores de riesgo fueron labvorales (4 por ciento); hereditarios (2 por ciento); o dfesconocidos (9 por ciento)(AU)

Cáncer de vejiga: tabaco como factor de riesgo / Bladder cancer: tobacco like risk factors

Entre setiembre de 1997 y marzo de 1998 se diagnosticaron y trataron en nuestro servicio 45 pacientes con cáncer de vejiga, de los cuales 41 casos fueron carcinomas superficiales, 3 infiltrantes y el restante carcinoma "in situ". El objetiv o del presente trabajo fue observar cuáles eran los factores de riesgo para el desarrollo de esta neoplasia. Se detectó que en el 85 por ciento de estos pacientes el hábito de fumar se encontraba presente (p<0,01), determinándose además la relación entre la cantidad de cigarrillos consumidos por día y el grado de diferenciación celular. Se registró también que los pacientes que fumaban tabaco negro desarrollaron tumores de mayor estadio de infiltración. En los restantes pacientes los factores de riesgo fueron labvorales (4 por ciento); hereditarios (2 por ciento); o dfesconocidos (9 por ciento)

Predicción de días de estada en unidades de cuidados intensivos usando redes neuronales artificiales / Length of stay prediction in intensive care units using artificial neural networks

La determinación de los días de estada, al momento de la admisión, es un factor importante para la toma de decisiones tanto clínicas como administrativas. Actualmente, existen diferentes trabajos que enfrentan el problema de la determinación de estadía, basados en modelos estadísticos lineales, los cuales son limitados en sus capacidades representacionales. Aquí se utilizan datos retrospectivos de 288 pacientes admitidos en la unidad de cuidados intensivos de adultos de tres hospitales chilenos. Se caracteriza la severidad de la enfermedad de los pacientes al momento de la admisión, cuantificando nominalmente los diagnósticos e incluyendo otras variables de severidad. La estadía se modela usando redes neuronales multicapa (Backpropagation). Los resultados del ajuste arrojan errores menores que 3 por ciento para predicción de días de estada y mediante un análisis de sensibilidad de la red, es posible obtener información clínica relevante de los factores que influyen en la estadía

Efecto inhibitorio de ciclosporina y prednisona sobre la fibrosis pulmonar por bleomicina en la rata / Inhibitory effect of cyclosporin-A and prednisone on bleomycin-induced pulmonary fibrosis in the rat

La administración intratraqueal de bleomicina (BLM) induce una fibrosis pulmonar en la rata detectable al cabo de 14 días. Tanto la ciclosporina-A como la Prednisona (administrada contemporáneamente con la bleomicina y luego diariamente hasta 14 ó 30 días después de BLM) disminuyen en cerca del 50 por ciento la fibrosis pulmonar inducida por bleomicina (Puntaje histopatológico). El Própósito de este estudio fue determinar si la ciclosporina y la prednisona administradas una vez que la fibrosís pulmonar estaba ya establecida eran capaces de inhíbirla. 1 U de BLM/100 g de peso corporal fue administrada intratraquealmente y las ratas se sacrificaron 14 y 30 días después. Se inyectó ciclosporina (0,15 mg/lOO g/día, ip) y/o prednisona (0,1 mg/1OO g/día, ip) desde el día 14 al 30 post-BLM. Prednisona o ciclosporina disminuyeron en cerca del 50 por ciento la fíbrosis pulmonar inducida por BLM. Sin embargo, la asociación prednisona + ciclosporina redujo la fíbrosis en sólo 40 por ciento. La disminución de la fibrosis pulmonar estuvo asociada a cambios en el líquido del lavado broncoalveolar: recuento celular, contenido de proteínas y fosfolípídos y actividad gama glutamil transpeptídasa. Se concluye que la prednisona y la ciclosporina son capaces de disminuir una fibrosís pulmonar ya establecida inducida por BLM en la rata

Remodeling of chromatin during male pronucleus formation in the sea urchin Tetrapygus niger.

After fertilization the cone shaped sperm nucleus is transformed into a spheroidal male pronucleus which fuses with the female pronucleus reestablishing the diploid genome. These morphological changes are correlated with biochemical transitions of sperm-specific chromosomal proteins. To obtain information on the rearrangements of chromosomal proteins after fertilization, we have followed sperm-specific nonhistones (Sp NHCP) and the sperm-specific histones (SpH) in zygotes harvested at different times post-insemination (p.i.). The acquisition of proteins synthesized de novo was determined during the time of male pronucleus formation, estimated to occur until 30 min p.i. The results obtained may be summarized as follows: 1. The fate of Sp NHCP, followed by Western blot analysis with polyclonal antibodies obtained in rabbits against the whole complement of Sp NHCP, indicates that the majority of Sp NHCP are lost shortly p.i., except two proteins of 58 Kd and 61 Kd that were not distinguishable from eggs NHCP because a crossreaction was obtained. Acidic proteins synthesized de novo were bound to chromatin between 3 and 30 min p.i., and the majority of these proteins comigrated with egg NHCP in SDS/PAGE. 2. The histones from sperm differ from their counterparts found in unfertilized eggs, both in their amino acid composition and their microheterogeneity in bidimensional gels. Sperm contain the five major SpH whereas eggs have seven major histone variants, distinct from each other, with an electrophoretic behaviour consistent with histones but a different amino acid composition. The total complement of histone variants found in zygotes collected at amphimixis is identical with that found in unfertilized eggs, suggesting that SpH should be lost before that time.(ABSTRACT TRUNCATED AT 250 WORDS)