Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.6 (thromboplastin)
 13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ProC Global is a clotting assay designed to globally evaluate the functionality of the protein C (PC) pathway, which is found defective in up to 30% of the Caucasian patients with thrombophilia. It is based on the ability of endogenous activated protein C (APC), generated by activation of PC by a snake venom extract, to prolong an activated partial thromboplastin time (APTT). This retrospective study was carried out to evaluate the ability of this assay to distinguish patients with or without any PC pathway abnormalities in a cohort of 899 unselected patients with a history of thrombosis. The result of the ProC Global assay, expressed in PC activation time-normalized ratio (PCAT-NR), was significantly lower in patients in whom was previously demonstrated an abnormality of the PC pathway compared to those without. The cut-off level of PCAT-NR=0.75 was found to provide the best sensitivity-specificity ratio, since all the patients with the factor V (FV) Leiden mutation (n=71), APC resistance (n=3), PC deficiency (n=22), or combined defects (n=19) had a PCAT-NR below that value. The sensitivity of the ProC Global assay for a low protein S (PS) level (n=56) was only 66%, and was even weaker in the case of hereditary PS deficiency (46.6%, n=15). The assay did not perform well in samples from patients on oral anticoagulant treatment (OAT, n=64) or with liver failure (n=4), as the PCAT-NR was reduced in most cases, even in the absence of any abnormality. These results suggest that the ProC Global assay could be validly used as a first-step screening test for the FV Leiden-related APC resistance and PC deficiency in patients not on OAT. Given the moderate sensitivity of the assay for PS deficiency, this coagulation inhibitor must be determined in every case. However, the overall benefit of such a screening strategy is limited since more than 38% of the 659 patients without abnormality had a decreased PCAT-NR.
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PMID:Sensitivity of the ProC global assay for protein C pathway abnormalities. clinical experience in 899 unselected patients with venous thromboembolism. 1167 53

To improve the safety of blood collection, plastic tubes have been developed but various interactions with the coagulation system and/or antithrombotic drugs were reported with the first generation of such tubes. The aim of this multicentre study was to compare hemostasis test results measured in evacuated plastic tubes made of polyethylene terephtalate (VenoSafe, Terumo Europe) and in siliconized glass tubes containing the same citrate concentration (0.129 M). In addition, the impact of aging of the plastic tube was investigated by collecting blood samples in tubes at 8 months and at 1 month before expiry. Blood was drawn in 3 centres from untreated patients (n=269), patients on oral anticoagulant treatment (OAT, n=221), and patients treated with either unfractionated heparin (UFH, n=73) or a low molecular weight derivative (LMWH, n=48). Prothrombin time (PT) or INR, activated partial thromboplastin time (APTT) and anti-FXa activity were locally performed, when applicable. In untreated patients and in patients on OAT, PT and APTT values were found statistically shorter (p<0.05) when evaluated in plastic tubes than in glass tubes, except when PT was evaluated using a human thromboplastin. Surprisingly, significantly longer APTT and higher anti-FXa activities were obtained when blood from patients on UFH was drawn in plastic than in glass tubes. However, none of the differences had any clinical relevance (Bland-Altman analysis). In patients on anticoagulant treatment, there was no effect of aging of the plastic tubes. These results suggest that the plastic tube VenoSafe is suitable for coagulation testing both in untreated subjects and more interestingly in patients on traditional anticoagulant therapy during the whole shelf life indicated by the manufacturer.
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PMID:A new plastic collection tube made of polyethylene terephtalate is suitable for monitoring traditional anticoagulant therapy (oral anticoagulant, unfractionated heparin, and low molecular weight heparin). 1641 99

Atrial Fibrillation (AF) is the most frequent cardiac arrhythmia and its incidence increases with age reaching a 10% prevalence in the oldest old. Patients with AF have a five-fold increase in the risk of stroke. Current guidelines on AF management recommend the prescription of oral anticoagulant therapy in patients at medium and high risk of thromboembolic events. Advanced age is a risk factor for stroke in AF, but despite clear evidences a high rate of OAT under prescription is reported and particularly in the oldest old. Among the main causes of this phenomenon an enhanced risk of bleeding is often reported: this due to several factors: risk of falls, the presence of comorbidity and polifarmacy and a reduction in compliance and adherence that are common in the elderly. In recent years the international scenario in the management of OAT has significantly changed since the introduction of the new oral anticoagulants (NOA): Dabigatran, a direct thrombin inhibitor, and two oral factor Xa inhibitors Rivaroxaban and Apixaban, which have all been tested in randomized clinical trial (RELY, ROCKET-AF e ARISTOTLE) which have demonstrated non inferiority compared to warfarin in the prevention of thromboembolic events with an optimal safety profile. NOA could be an important therapeutic opportunity for stroke prevention in elderly patients with AF even if the substantial differences in mean age, anthropometric measures and comorbidity of the patients enrolled in these trials compared with those of the real world setting, oblige some caution and discussion.
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PMID:[Treatment of very old patients with non valvular atrial fibrillation. The valuable opportunity offered by new oral anticoagulants, to be cautiously used]. 2508 91