RESUMEN
Light transmission aggregometry (LTA) is considered the gold standard method for evaluation of platelet function. However, there are a lot of variation in protocols (pre-analytical procedures and agonist concentrations) and results. The aim of our study was to establish a national LTA protocol, to investigate the effect of standardization and to define national reference values for LTA. The SSC guideline was used as base for a national procedure. Almost all recommendations of the SSC were followed e.g. no adjustment of PRP, citrate concentration of 109 mM, 21 needle gauge, fasting, resting time for whole blood and PRP, centrifugation time, speed and agonists concentrations. LTA of healthy volunteers was measured in a total of 16 hospitals with 5 hospitals before and after standardization. Results of more than 120 healthy volunteers (maximum aggregation %) were collected, with participating laboratories using 4 different analyzers with different reagents. Use of low agonist concentrations showed high variation before and after standardization, with the exception of collagen. For most high agonist concentrations (ADP, collagen, ristocetin, epinephrine and arachidonic acid) variability in healthy subjects decreased after standardization. We can conclude that a standardized Dutch protocol for LTA, based on the SSC guideline, does not result in smaller variability in healthy volunteers for all agonist concentrations.
Asunto(s)
Fototerapia/métodos , Recuento de Plaquetas/métodos , Pruebas de Función Plaquetaria/métodos , Voluntarios Sanos , Humanos , Países BajosRESUMEN
The correlation between age, proliferation rate of tumors, estrogen and progesterone receptors, and in vitro chemosensitivity to Adriamycin was studied on 43 primary mamma tumors. From an univariate statistical analysis of the results, it appeared that sensitive tumors, unlike resistant tumors, have fewer estrogen receptors and show a higher proliferation rate. And in addition, they are blocked to a greater extent by Adriamycin. In both groups age and progesterone receptors were not significantly different. A multivariate statistical analysis showed that in the classification into sensitive and resistant tumors, the percentage remaining incorporation after addition of Adriamycin and the proliferation rate contributed 94 and 5%, respectively. The first variable was the best measure for in vitro chemosensitivity. The classification of the tumors with the aid of a discriminant function proved to be successful in 91% of all the cases. No significant difference was observed between the in vitro sensitivity to Adriamycin when patients were divided into two groups according to age (less than or equal to 50 and greater than 50 years; 64 and 45% sensitive, respectively). This indicates that all patients benefit from the treatment. It also appeared that 85% of the estrogen negative tumors were sensitive to Adriamycin. So a chemotherapeutic instead of a hormonal therapy has to be considered for all ages, particularly in the case of estrogen negative receptors.
Asunto(s)
Biomarcadores de Tumor/análisis , Neoplasias de la Mama/tratamiento farmacológico , Doxorrubicina/farmacología , Receptores de Estrógenos/análisis , Receptores de Progesterona/análisis , Factores de Edad , Análisis de Varianza , Neoplasias de la Mama/patología , Neoplasias de la Mama/cirugía , División Celular/efectos de los fármacos , Doxorrubicina/uso terapéutico , Femenino , Humanos , Menopausia , Persona de Mediana Edad , Pronóstico , Células Tumorales Cultivadas/citología , Células Tumorales Cultivadas/efectos de los fármacosRESUMEN
This study has been initiated by the definite need of a rapid, in vitro and patient-specific test to examine oncolytic drug effects on tumour cells. Therefore, we applied a test in which we monitored the incorporation of labelled nucleosides in isolated tumour cells, as a measure of nucleus activity (i.e. the Volm assay). A novel technique of erythrocytes co-precipitation has been developed and this enabled us to use a small number of tumour cells per test (200,000 cells/tube). During the assay, a strict pH control and a high starting viability have been introduced. A cytotoxic control and a t-test at two levels deal with the technical errors and the imprecision. For the evaluation of a specific drug a number of 1.8 million cells proved to be sufficient. Time-course studies of the incorporation of labelled nucleosides into isolated tumour cells have shown the optimal incubation time to be 2 h. The entire assay is completed within one day. HeLa cell cultures were employed as quality control material and criteria for interpretation have been developed. Preliminary results, based upon the evaluation of 43 human breast tumours with doxorubicin, indicate the correctness of the proposed procedures. In conclusion we can state that this assay not only provides useful information but above all that the results are made available in such a short time that they can be used directly in the medical management of the individual patient.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias de la Mama/patología , Supervivencia Celular/efectos de los fármacos , Medios de Cultivo , Doxorrubicina/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Humanos , Concentración de Iones de Hidrógeno , Control de Calidad , Azul de Tripano , Células Tumorales Cultivadas/efectos de los fármacos , UridinaRESUMEN
comparative studies on bilayer systems of saturated phosphatidylcholines and phosphatidylethanolamines revealed a maximum in ionic permeability in phosphatidylcholine bilayers at the temperature of the gel to liquid-crystalline phase transition but such an increase in permeability was not detectable in bilayers of phosphatidylethanolamine. Furthermore, it was found that at the phase transition temperature the phosphatidylcholine bilayers are subject to rapid hydrolysis by pancreatic phospholipase A2 whereas phosphatidylethanolamine bilayers are not. These differences are discussed in view of detailed information on the molecular organization in the gel and liquid crystalline phases of the two phospholipid classes.