ABSTRACT
BACKGROUND: The thrombin generation (TG) assay can assess individual clotting potential. The thrombin generation potential is correlated with the patient's bleeding phenotype and varies from one patient to the other for the same degree of factor VIII or IX deficiency. OBJECTIVE: To define in vitro for individual haemophilic patients the target factor VIII or IX level required to normalize their TG. PATIENTS/METHODS: Plasmas from 20 haemophilic patients were spiked with increasing levels of the deficient coagulation factor and TG parameters were measured. The relationships between factor levels and TG parameters were determined by linear regression. The normal range of thrombin generation was defined in 39 healthy male volunteers. RESULTS: Despite inter-individual heterogeneity in basal TG and responses to spiking, a linear relationship was found between factor VIII or IX levels and TG parameters for individual patients. Based on the individual responses of patient plasmas to spiking, it is possible to define in vitro the target factor VIII or IX levels needed to normalize the TG parameters. For both haemophilic A and haemophilic B patients, significant correlations were found between basal peak values and their correction slopes. The correction slope was steeper in haemophilic B patients, so the factor IX level needed to normalize the TG parameters was lower than for haemophilic A patients. CONCLUSIONS: The TG assay could be used to determine in vitro the patient-specific factor VIII or IX level to be reached to effectively normalize their TG. These in vitro results should be confirmed by ex-vivo studies.
Subject(s)
Factor IX/metabolism , Factor VIII/metabolism , Hemophilia A/metabolism , Thrombin/biosynthesis , Female , Hemophilia A/blood , Humans , MaleABSTRACT
This paper deals with the application of two in situ particle sizing methods to the study of aggregation of titanium dioxide in turbulent aqueous solutions. Turbidity measurements are used to characterize aggregation of diluted suspensions (solid volume fraction less than 10(-4)). Analysis of backscattered light can be applied to highly concentrated suspensions. Because in situ measurements are possible, the aggregation process can be followed from its beginning to the final steady state which is always observed. The influences of stirring rate and solid volume fraction on the aggregation dynamics are presented. They are interpreted in the framework of a model of aggregation which takes into account the morphology and the related optical properties of the aggregates and the physical and hydrodynamic interactions between aggregates. The complex relationship between aggregate restructuring and aggregation on one hand, and fragmentation on the other hand, is considered. Copyright 2000 Academic Press.
ABSTRACT
Intraperitoneal chemohyperthermia is more and more considered as an interesting therapeutic option in cases of some abdominal cancers, particularly of digestive origin. However, many technical aspects of this treatment remain far from being mastered, particularly the homogeneous dispatch of temperatures within the abdomen cavity. This work consists, first of all, in an experimental study, which is being carried out on a physical "prototype" of the abdomen, on which different hot fluid flows and injection conditions (configurations) are investigated. The results of this experimental study are prospected in two ways. First, an a priori thermal model is proposed, based on physical equations (heat transfer, etc.). Then a "black box" model is identified from the measured temperatures evolutions, so as to obtain a model of the "system" behaviour. Finally, the two modelling approaches are being compared, and the results converge to a simple expression of a few parameters, either physical or identified. These modelling results have helped to optimize the injection circuit and its running parameters while applied to the human treatment.
