Potencia sedante de diferentes midazolam endovenosos, determinada a través de índice biespectral / Sedative potency of different intravenous midazolam, determined through bispectral index

Desde hace un tiempo se han escuchado comentarios en el ambiente Anestesiológico y de Medicina Intensiva, respecto a diferencia en la potencia sedante entre las diferentes alternativas de Midazolam ev disponibles en el mercado nacional. Se mide y compara la potencia sedante de 4 distintos Midazolam disponibles en el mercado nacional, con un monitor de Indice Biespectral (BIS), que determina la profundidad de la hipnosis a través de la medición de la actividad eléctrica neuronal cortical del cerebro, predominantemente frontal. Los niveles de sedación habituales para BIS son de alrededor de 80 para sedación superficial y del orden de 70 para sedación profunda. Método: Población de 80 pacientes adultos, de ambos géneros, ASA I, programados para Anestesia General(AG) o Anestesia Regional (AR) en cirugías electivas y de urgencia, que son sedados ya sea antes de AG o después de AR. A cada paciente se le explica de la manera más clara posible el procedimiento y se le pide su consentimiento para incluirlo en el estudio. Del universo de 80 pacientes, resultan cuatro grupos de 20, a quienes luego de una selección randomizada y aleatoria de una de las 4 alternativas de Midazolam, se les administra 0,02 mg/kg ev. Se determina aleatoriamente por un colaborador, cuál de las cuatro alternativas del fármaco se utiliza, misma que en ningún momento es de conocimiento del médico anestesiólogo a cargo de la medición. Se determina el nivel de BIS basal luego de la instalación de la monitorización y antes de realizar la administración de Midazolam. Se les mide el BIS transcurrido un (1) min, a los 3 min, a los 5 min, y finalmente a los 10 min de administrado el fármaco. Resultados: Muestran con claridad que la disminución de los valores de BIS, luego de administrado el fármaco es categóricamente mayor para Midazolam original. Se muestra también que el comportamiento del valor del BIS en las otras tres alternativas de Midazolam es similar. El análisis estadístico de los resultados fue encargado al Sr. Luis A. Villarroel Del Pino, Estadístico de la Facultad de Medicina de la PUC. Conclusión: La conclusión más relevante es que Midazolam original tiene mayor potencia sedante que las otras alternativas del fármaco estudiadas. Esto es con respecto al efecto medido en el monitor de BIS, sin considerar ningún parámetro clínico de sedación y con la dosis elegida para el presente estudio.

[Axenic and polyxenic antigens of Entamoeba histolytica in the diagnosis of human amebiasis]. / Antígenos axénico y polixénico de Entamoeba histolytica en el diagnóstico de la amibiasis humana.

A comparison of the antigenic activity of soluble extracts of Entamoeba histolytica kept in axenic and polyxenic cultures is undertaken. Special care was kept so as to keep the protein native structure unharmed. Chromatographic separation at G-200 was performed, and three fractions were obtained and submitted to reactions with the sera of 10 patients with a proven diagnosis of amebic hepatic abscess, 5 patients with amebic dysentery from whom the protozoon was isolated and cultured from feces, and finally from 10 control subjects. The ELISA technique was employed to detect the levels of antibodies, using the raw, soluble, antigens and the chromatographic ones which were obtained. The specificity of the antibodies was analyzed with I.E.E., and a spectrophotometric reading of the raw, soluble, antigens adsorbed was performed by chromatographic affinity, with sepharose columns joined with purified immunoglobulins extracted from the seric combinations of each one of the studied individuals. Our results prove that the values of D.O. of the ELISA, when a soluble SAX I fraction is used, are statistically significant when compared with the raw, soluble, antigen, and this fraction allows discrimination between patients with intestinal and extraintestinal amebiasis. Specific reactivity was demonstrated by antigenic, proteic, bands opposed to the sera from patients with hepatic abscesses, with the use of axenic, soluble antigen, as well as at least one proteic band which reacts with the sera of patients with amebic dysentery. Proteic bands that react indistinctly with immunoglobulins from the three studied groups were demonstrated. The polyxenic, soluble extract demonstrated a proteic band recognized by the sera from patients with amebic dysentery.

Release of PAF by human polymorphonuclear leucocytes stimulated by immune complexes bound to Sepharose particles and human erythrocytes.

Human polymorphonuclear leucocytes (PMN) incubated with surface-bound immune complexes (IC) release a substance that induces platelet aggregation and serotonin-release. This substance was identified as platelet-activating factor (PAF) on the basis of its sensitivity to phospholipase A2 and of its purification by thin-layer chromatography in identical conditions to those used to purify zymosan-induced PAF. We used two types of substrates to absorb our IC:Sepharose particles to which we coupled human serum albumin, and which were later incubated with specific rabbit antiserum to form surface-bound immune complexes, and human erythrocytes, to which soluble IC can be passively adsorbed. Both types of surface-bound IC were found to stimulate the release of PAF by human PMN in the absence of complement. These results suggest that PMN may play a central role in the early stages of IC-induced inflammation: they recognize IC adsorbed to red cells or to any other cell able to adsorb IC, and they induce the activation of platelets and release of vasoactive amines, which leads to the increase of vascular permeability believed to be essential for extravascular IC deposition.