A New Approach to Estimate Safe Maximum Fortification Levels for Micronutrients.

Objectives: Maximum fortification levels for voluntarily fortified foods are meant to guard against excessive micronutrient intake. Existing methods of estimating safe maximum levels take a conservative approach by considering a single point in the intake distribution of the micronutrient of interest. The free space for fortification has traditionally been estimated as the tolerable upper intake level minus an observed high intake value (e.g., 95th percentile), with or without considering the contribution of supplements. Using a single value from the distribution results in a single estimate of a safe maximum fortification level. This potentially results in unrealistically high estimates. We propose a probabilistic approach for setting safe maximum fortification levels. Methods: We build upon the estimation of i) a measure of the amount of the food supply that is potentially fortifiable with a micronutrient (i.e., the ‘fortifiable pool'), and ii) a ‘free space' available for intake from voluntarily fortified sources. As a proxy for the fortifiable pool, we utilize the fraction of energy provided by potentially fortifiable foods. The energy from the fortifiable pool and nutrient intake from food and supplemental sources are then jointly modeled. Results: Applying this probabilistic approach to the estimation of safe maximum fortification levels provides a distribution of safe maximum fortification levels from which an appropriate level can be chosen. Conclusions: This approach can estimate safe maximum fortification levels that more realistically convey the potential benefits to be achieved by increased micronutrient intake through voluntary fortified foods, as well as the risks associated with excessive intake.

Muerte encefálica: consideraciones clínicas y legales / Brain death: clinical and legal considerations

Temor y ambivalencia son aspectos centrales en la matriz sociocultural relacionada con la muerte encefálica. Para el médico que debe evaluar pacientes y certificar el diagnóstico de muerte encefálica es crucial contar con una sólida comprensión de la fisiopatología, los criterios diagnósticos y de los exámenes complementarios. La existencia de un marco legal coherente y completo para el diagnóstico de muerte encefálica, independiente de la potencial donación de órganos, es ciertamente crucial para el médico. La relevancia que tiene en este sentido el fallo del Tribunal Constitucional de Chile del 13 de agosto de 1995 se analiza en profundidad.

Fear and ambivalence are key aspects of the sociocultural frame related to brain death. For those physicians who have to evaluate patients and certify the diagnosis of brain death a sound comprehension of the physiopathology, the clinical features and the complementary diagnostic test is crucial. The existence of a comprehensive and coherent legal regulation for the diagnosis of brain death, clearly independent of the potential of organ donation is also crucial. The relevance of the judgment given in 1995 by the Chilean Constitutional Court to provide these consistency is pointed out.

surface electrical properties of splenic lymphocytes of bilharazial and non-bilharzial subjects

The membrane surface electrical properties of spleine lymphocytes from an accident victim [control] and from Egyptian bilharzial patients were studied by electro-rotation. Phytohaemagglutenines [PHA-P and PHA-M] or pokeweed [PWM] were the mitogens used for cell stimulation. The unstimulated bilharzial lymphocytes had larger radii than those from the control probably because they were already stimulated by the disease state. After stimulation, all lymphocytes increased steadily in size and consequently in membrane are. The values for membrane capacity [C[M]] were higher for control lymphocytes than for bilharzial cells. All CM values were increased with the duration of stimulation except for the bilharzilal cells incubated with PMW, which peaked on day 1 and deteriorated very rapidly after that. The values calculated for membrane conductivity [G[M]] followed a different pattern. The C[M], levels exhibited peak values after different durations of stimulations depending on the cell type [control or bilharzial] and the mitogen used. The changes in conductivity may reflect alterations in transmembrane transfer activity

In Vitro influence of some local anaesthetics on the surface electrical properties of erythrocytes

Four molecules [Procaine, Tetracaine, Bupivacaine and Lidocaine] of either the ester or amide type of local anesthetics were studied. Erythro-cytes were used to provide the membrane model. The surface electrical properties were determined by the electro-rotation technique. It was found that the surface conductance, Ks was the most sensitive parameter, while the membrane capacity [CM] refractory to treatment with the local anesthetics tested. The values for Ks decreased with the increase in the concentrations of the local anesthetics giving concentration-response relationships. The values of the EC50 were found to be in the following order: Tetracaine [22.63 nM] > Bupivacaine [45.91] > procaine [59.57 nM] = Lidocaine [59.73 nM]. The values were inversely proportional with lipid/water partition coefficients of the respective molecules

Unidades de tratamiento del ataque cerebrovascular (UTAC) en Chile / Stroke units in Chile

Stroke is a major public health problem in Chile, with an incidence similar to that of many industrialized nations, it accounts for 10% of all deaths and ranks 5th in number of healthy years of life lost to a disease. Organized inpatient care for stroke patients has been shown in systematic reviews of randomized clinical trials to be effective in preventing death, disability and institutional care, without increasing length of stay compared to usual care. Organized stroke unit care is provided by multidisciplinary teams that exclusively manage stroke patients in a dedicated ward (stroke ward) of which there are various possible models; acute stroke units which accept patients acutely but discharge early (usually within 7 days). This could include an "intensive" model of care with continuous monitoring and high nurse staffing levels; comprehensive (i.e. combined acute and rehabilitation) stroke units which accept patients acutely but also provide rehabilitation for at least several weeks if necessary. The way in which stroke units affect outcome is through reduction of complications of immobility and probably non specific neuroprotection. Stroke units should deliver high quality evidence based interventions to all eligible patients and should maintain high standards of care through staff training, guidelines and protocols, audit and quality assurance. Given that stroke is one of the fifty six health priorities in the health reform, inpatient stroke care should be delivered through stroke units organized in hospitals throughout Chile.

Predicción clínica de aspiración en pacientes con patología neurológica aguda / Clinical prediction of aspiration in acute neurological patients

Glottic dysfunction is a frequent condition in patients with acute neurological diseases: the incidence in stroke patients is between 45 - 51 percent increasing mortality three times. The principal complication is aspiration, which demands the involvement of pulmonary physicians and neurologists. The purpose of this study is to evaluate wet voice, water swallow test and cervical auscultation as clinical predictors of aspiration using endoscopical observation as a gold standard. During a period of one year we have prospectively evaluated these tests in acute neurological patients hospitalized in an intensive care unit. Wet voice, 3 oz water swallow test and cervical auscultation demonstrated sensibilities of 66.7, 88.9 and 77.8 percent, with a respective specificity of 85.2, 59.3 and 77.8 percent. Positive predictive values were 60, 42.1 and 53.8 percent, with negative predictive values of 88.5, 94.1 and 91.3 percent respectively. These results support the utility of clinical aspiration screening as a simple and valuable technique that can be done at the bedside.

La disfunción glótica es una entidad prevalente en enfermos con patología neurológica aguda: compromete aproximadamente entre el 45 al 51 por ciento de los pacientes que padecen un ataque cerebrovascular, incrementando su mortalidad en una relación de 3/1. Su complicación principal es el síndrome aspirativo, que involucra diversas especialidades, entre ellas enfermedades respiratorias y neurología. El propósito de este estudio ha sido evaluar la fonación húmeda, el test del vaso de agua y la auscultación cervical como indicadores clínicos de aspiración frente a la certificación nasolaringoscópica, considerada patrón estándar de evaluación al lado de la cama del enfermo. Evaluamos prospectivamente durante un año a pacientes neurológicos agudos hospitalizados en una unidad de tratamiento intensivo. La fonación húmeda, el test del vaso de agua y la auscultación cervical demostraron sensibilidades de 66,7, 88,9 y 77,8 por ciento, con una especificidad respectiva de 85,2, 59,3 y 77,8 por ciento. Los valores predictivos positivo fueron de 60, 42,1 y 53,8 por ciento, con valores predictivos negativo de 88,5, 94,1 y 91,3 por ciento respectivamente. Nuestros resultados permiten afirmar que el monitoreo clínico de aspiración es un instrumento sencillo y valioso, que puede ser realizado al lado de la cama del enfermo.

Encefalomiopatía mitocondrial, acidosis láctica y apariencia de accidentes vasculares cerebrales / Mitochondrial, lactic acidosis and features of cerebrovascular disorders

En una paciente de 12 años de edad, aparentemente sana hasta los 9 años, con epilepsia progresiva, deterioro mental, acidosis láctica y déficit neurológicos que simulaban accidentes cerebrovasculares, la biopsia muscular demostró fibras rojas desflecadas y acúmulos de mitocondrias anormales, confirmando el diagnóstico de encefalomiopatía mitocondrial. Conviene pensar en este grupo de enfermedades en pacientes escolares con cefalea periódica, epilepsia mioclónica que responde mal al tratamiento, hipoacusia sensorioneural y deterioro mental. Las manifestaciones musculares pueden ser frecuentemente tardías