SummaryHuman umbilical vein endothelial cells (HUVEC) were cultivated on globular microcarriers in order to improve the endothelial cell surface to blood-volume ratio over the conventional flat bed cultures. HUVEC-beads were tested for their modulation of blood coagulation using a combination of two steps: HUVEC-beads were added into the syringe used for the venipuncture, in order to achieve immediate contact between cells and blood, and no anticoagulant was used during the incubation time of HUVEC-beads with whole blood. The coagulation initiation produced by venipuncture was almost completely suppressed as judged by thrombin measurements over a period of 60 min. The activated partial thromboplastin time showed a prolongation by a factor >3. Direct measurements of activated protein C (APC) were negative. Moreover, inhibition of APC-generation with a monoclonal anti-human protein C antibody did not affect the anticoagulant properties of endothelial cells. Therefore the anticoagulant properties exerted by HUVEC-beads are not dependent on APC.
To cite this article: Depasse F., Gerotziafas G. T., Busson J., Van Dreden P., Samama M.M. Assessment of three chromogenic and one clotting assays for the measurement of synthetic pentasaccharide fondaparinux (Arixtra Synthetic pentasaccharide fondaparinux (Arixtra 1) is the ®rst indirect (antithrombin-dependent) synthetic speci®c factor (F)Xa inhibitor approved in several countries for the prevention of deep vein thrombosis (DVT) in major orthopedic surgery. In addition, ongoing clinical trials aim to prove its ef®cacy for the treatment of DVT and in coronary heart disease (for review see [1,2]). Fondaparinux plasma concentrations obtained in patients treated at prophylactic and therapeutic doses range from 0.1 to 0.5 mg mL À1 and from 0.6 to 1.5 mg mL À1, respectively; in healthy volunteers, the subcutaneous injection of the established prophylactic dose (2.5 mg) is associated with plasma levels at 0.34 AE 0.04 mg mL À1 [3±5]. Although no coagulation monitoring is advocated, accurate assays dedicated to anti-Xa activity measurement should be available. This could be useful in practical use at least in some particular groups of patients, e.g. with renal impairment, during pregnancy, body weight < 50 kg as recommended for LMWHs or in the elderly. Nevertheless, no special assay has been developed for this purpose and the commercial available assays are designed for either unfractionated or low molecular weight heparins. The aim of this work was to evaluate the possibility of using commercially available assays. Three different chromogenic and one clotting assays for the measurement of fondaparinux anti-Xa activity in plasma were evaluated.Normal pool plasma (Normapool 1 , Hyphen BioMed, Neuville sur Oise, France) was spiked with increasing amounts of fondaparinux (Sano®, Paris, France) in order to obtain plasma concentrations ranging from 0 to 10 mg mL À1 . The antithrombin activity level was measured in this range of concentrations using the Berichrom 1 Heparin was used with addition of exogenous bovine antithrombin as provided with the assay and without addition of exogenous antithrombin. In addition to the results expressed in LMWH anti-Xa IU mL À1 , results were registered as raw data, i.e. optical density variation per minute (DOD min À1 ) and clotting time for the chromogenic and the clotting assays, respectively. FXa inhibition for the chromogenic assays was calculated by reporting the DDO min À1 of the considered sample to the DDO min À1 of the normal pool plasma free of fondaparinux considered as baseline. A statistical analysis was performed using an analysis of variance (ANOVA, F-test).All the antithrombin activity levels measured remained in the normal range and were not signi®cantly affected by the addition of fondaparinux.Results expressed in LMWH anti-Xa IU/mL differed signi®cantly (P < 0.01) from an assay to another for the same fondaparinux plasma concentration, e.g. (mean AE SD, n 10) 0.93 AE 0.03 IU mL A linear relationship was obtained for fondaparinux plasma concentrations ranging from 0 up ...
Intoxicated patients make up 5-10% of all patients seen at emergency departments. The management of these patients is not always simple. Many of them are seen after ingestions of relatively non-toxic substances that require minimal medical care, intentional poisoning however often requires the highest standards of medical and nursing care and therefore the admission to an emergency department is mandatory. At admission, the involved substances are often not known since some of the patients are comatose. In such cases, the information from relatives and friends can be very crucial but to get hold of these sometimes essential "hints" is not always easy. Knowledge of the specific toxic agent allows the physician to plan a rational approach to the definitive management of the intoxicated patient after the vital functions have been stabilised. In some cases, very rare intoxications but with typical clinical signs do occur (e.g scromboid fish poisoning, coprinus-syndrome), which needs special diagnostic and therapeutic steps and a great deal of clinical experience. In most cases it is preferable to contact the Poison Control Center for additional advice.
Nur wenige klinische wie auch diagnostische Entscheide in der Medizin werden so vielfältig und zum Teil kontrovers diskutiert wie die Abklärungsschritte beim Patienten mit akutem Thoraxschmerz. Besonders schwierig ist der Entscheid, welche Patientinnen und Patienten mit welchem diagnostischen Aufwand sicher aus der Notfallstation oder der Hausarztpraxis entlassen werden können. Es besteht sehr oft die Möglichkeit, dass für den Patienten ernsthafte Diagnosen verpasst werden, welche zu einer substantiellen Morbidität und Mortalität führen können. Der Einsatz des noch so guten Algorithmus für den «unklaren Thoraxschmerz» reicht nicht immer aus, um Fehldiagnosen sicher ausschließen zu können. Hier ist der Arzt mit all seinen klinischen Erfahrungen und seinem «Fingerspitzengefühl» gefragt! Der folgende Artikel befasst sich insbesondere mit diagnostischen Tests wie das EKG, den Biomarkern Troponin und D-Dimer, aber auch mit der Abklärung von Patienten mit Verdacht auf Lungenembolien mittels Spiral-CT. Der Artikel befasst sich aber auch mit der Wertigkeit von repetitiven diagnostischen Tests und der Wichtigkeit der Bestimmung des ungefähren Zeitintervalls zwischen den ersten klinischen Symptomen und der Vorstellung beim Arzt. Dieses Zeitintervall kann für das diagnostische «work-up» des Patienten mit akutem Thoraxschmerz von zentraler Bedeutung sein.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.