Visible spectro-photometric determination of cerberin in rat plasma.

The present paper aims to develop a simple direct colorimetric method for the determination of cerberin in rat plasma without any previous chemical separation of the cerberin from Cerbera odollam. The method is based on reaction of the cardenolide group of cerberin with 3,5-dinitro salicylic acid [DNS] in alkaline medium which yields a bright orange-yellow complex that exhibits absorption maxima at 370nm.Beer’s law obeyed in the concentration range of 50-250μg/mL. The result of the method was validated statistically and by recovery studies.

Dissolved ozone in biological fluid monitored by optical device operating in the red-infrared region

INTRODUCTION: When a gas is used for therapy, often the kinetic behavior and their distribution in biological systems is not known, leading to unsatisfactory results for clinical application. The use of ozone in living organisms has been scientifically released worldwide under the name of ozone therapy. The efficacy of this technique is determined primarily by the diffusion of gas within the tissues or fluids and which determines their action in the entire target region. We propose the development of technique to monitoring the O3 dissolved in the biological fluid using an optical device operating in the red-infrared region. METHODS: The recombination of O3 in O2 enables the monitoring of the latter by the measurement of SpO2, and, based on this phenomenon, we propose to use an optical device operating in the red-infrared region to monitoring indirectly the diffusion of O3 in fluids. The system was based on optomechanical arrangement using a capsule containing fluid that was ozonated or oxygenated during the process. A pulse oximeter is a noninvasive device used for continuously measure of SpO2 resulting from the recombination of ozone. RESULTS: The measurements of SpO2 when subjected to ozone and oxygen, showed an increased rate of SpO2 function of time for both cases reaching its peak in 80s and 160s, respectively. The experimental data concerning the SpO2 saturation as a function of time can be fitted by the theoretical model, showing a good correlation between them. CONCLUSION: A technique was developed using an optical device operating in the red-infrared region to monitoring ozone dissolved in biological fluid, showing a simple and effective way to indirectly monitoring the presence of ozone in fluids.

Determinación de la bioactividad de capas de alginato de sodio en discos de hidroxiapatita / Determination of bioactivity in sodium alginate layers of hydroxyapatite disks

OBJETIVO: el propósito central de este trabajo es evaluar la bioactividad in vitro de capas de alginato de sodio en discos de hidroxiapatita. MÉTODOS: los discos de hidroxiapatita fueron elaborados mediante procesos sucesivos de prensado y de sinterizado en un horno eléctrico. Las capas de alginato de sodio se obtuvieron empleando el método de sobrepresión y una disolución acuosa de alginato de sodio al 5 %. En el ensayo de bioactividad las muestras a estudiar fueron sumergidas en fluido biológico simulado. La caracterización de las muestras se realizó empleando microscopia electrónica de barrido y energía dispersiva de rayos X. RESULTADOS: en las muestras de hidroxiapatita sometidas al ensayo de bioactividad, con y sin capas de alginato de sodio, se observó la formación de precipitados ricos en calcio y fósforo. Además, se determinó que con el aumento del tiempo de inmersión en el fluido biológico simulado se incrementan las dimensiones de los aglomerados formados por partículas apatíticas. CONCLUSIONES: los resultados experimentales corroboran que la hidroxiapatita es bioactiva y demuestran que las capas estudiadas de alginato de sodio en discos de hidroxiapatita poseen un comportamiento bioactivo.

OBJECTIVE: the main purpose of the study is to evaluate in vitro bioactivity in sodium alginate layers of hydroxyapatite disks. METHODS: the hydroxyapatite disks were manufactured by successive pressing and sintering in an electric furnace. The sodium alginate layers were obtained by overpressure and a 5% sodium alginate aqueous solution. For the bioactivity assay, the study samples were soaked in simulated biological fluid. Characterization of the samples was conducted by scanning electron microscopy and energy dispersive X rays. RESULTS: the bioactivity assay of hydroxyapatite samples with and without sodium alginate layers revealed the formation of precipitates rich in calcium and phosphorus. It was also found that an increase in the time of immersion in the simulated biological fluid brought about an increase in the size of agglomerates of apatite particles. CONCLUSIONS: experimental results show that hydroxyapatite is indeed bioactive, and that the sodium alginate layers of hydroxyapatite disks which were studied behave bioactively.

Application of LC-MS/MS for quantitative analysis of glucocorticoids and stimulants in biological fluids / 药物分析学报

Liquid chromatography tandem mass chromatography (LC-MS/MS) is an important hyphenated technique for quantitative analysis of drugs in biological fluids. Because of high sensitivity and selectivity, LC-MS/MS has been used for pharmacokinetic studies, metabolites identification in the plasma and urine. This manuscript gives comprehensive analytical review, focusing on chromatographic separation approaches (column packing materials, column length and mobile phase) as well as different acquisition modes (SIM, MRM) for quantitative analysis of glucocorticoids and stimulants. This review is not meant to be exhaustive but rather to provide a general overview for detection and confirmation of target drugs using LC-MS/MS and thus useful in the doping analysis, toxicological studies as well as in pharmaceutical analysis.

Bomba de perfusión programable para uso biomédico

Este trabajo presenta el funcionamiento de un instrumento biomédico, diseñado y construido para cubrir los requerimientos de un grupo de investigadores en el área de bioquímica. El instrumento desarrollado tiene como propósito inyectar un fluido biológico a un sistema específico en una secuencia definida y programable, cuyo compuesto químico lo define el investigador. Dicha secuencia permite establecer diferentes velocidades de inyección del fluido en función del tiempo; todo ello, en un mismo ciclo de trabajo. Para cumplir con las características de funcionamiento se diseñó un sistema electrónico con microcontroladores y un sistema mecánico de precisión, que puede manejar una o dos inyectadoras de 3 centímetros cúbicos (cc) de uso comercial. La acción del sistema mecánico sobre las inyectadoras se encarga de inyectar el líquido en el medio o cuerpo de experimentación. El prototipo de este instrumento se está utilizando en el estudio del metabolismo de los atletas durante el ejercicio, en el laboratorio de investigación del Departamento de Bioquímica de la Facultad de Medicina de la Universidad de Los Andes.

This work presents the operation of a biomedical instrument, designed and built to cover the requirements of investigators group at the biochemistry area. The developed instrument has as purpose to inject a biological fluid, to a specific system in a defined and programmable sequence whose chemical compound the investigator defines. This sequence allows to establish different speeds of injection of the fluid in function of the time; everything it, in oneself work cycle. To fulfill the operation characteristics an electronic system it was designed with microcontrolers and a mechanical system of precision that it can manage an or two syringes of 3 cubic centimeters (cc) of commercial use. The action of the mechanical system on the syringes takes charge of inject the liquid in the means or experimentation body. The prototype of this instrument is used in the study of the metabolism of the athletes during the exercise, at the laboratory of investigation of the department of Biochemistry of the Ability of Medicine at the University of The Andes.