1,721,541 research outputs found
Laboratory Testing for Lupus Anticoagulants: a Review of Issues Affecting Results
No full textBackground: Lupus anticoagulants (LA) are a heterogeneous class of immunoglobulins. Persistent LA positivity is a risk factor for the occurrence and recurrence of venous/arterial thromboembolism and/or pregnancy morbidity and qualifies the patient for anticoagulation therapy. The laboratory diagnosis for LA that is used for crucial decision-making about the optimal duration of the therapy rests entirely on diagnostic criteria. These criteria are based on the prolongation of phospholipid-dependent tests not corrected upon mixing patient and normal plasmas, with confirmation provided by the evidence that the anticoagulant is directed against proteins bound to negatively charged phospholipids. Aims: This article reviews issues related to the diagnosis of LA, including the effect of preanalytical variables, choice of tests, results interpretation of screening, mixing and confirmation procedures, patients to be investigated, and transmission of results. Unresolved issues and future direction for research on laboratory diagnosis are also discussed. Methods: Search of PubMed with the key term "lupus anticoagulant" plus articles and unpublished data known to the author. Results and Conclusions: The preanalytical variables (i.e., plasma preparation and storage before analysis) as well as the diagnostic steps to detect LA present potential problems that undermine the process of making a correct diagnosis. A truly specific test for LA detection is badly needed, but its development may require understanding of the mechanisms associated with the occurrence of clinical events. Until then, clinical laboratories should rely on the existing procedures, which must be applied with caution and awareness of the many issues that may affect their results
Hemostasis in acute and chronic liver disease
Full text linkAcute and chronic liver diseases have long been considered prototypes of acquired hemorrhagic diseases. Over the last decade, evidence stemming from the laboratory bench and clinical practice has indicated that hemostasis abnormalities, until recently considered as the cause of bleeding in these conditions, are rebalanced to normal despite the abnormal results of the hemostasis tests such as prothrombin time and platelet counts. Consequently, the commonly used therapeutic approach the infusion of plasma, platelets, or other prohemostatic agents are not biologically plausible and should be reconsidered. In this article, the author reviews the evidence supporting the changing paradigm
Hydrogen Production by Steam Reforming of Bioethanol: Catalytic Tests and Process Design
No full textAbstract
2nd generation bioethanol was considered as raw material for the sustainable hydrogen production by catalytic steam reforming. An experimental kinetic investigation has been carried out selecting different catalysts synthesized by Flame Spray Pyrolysis, a one step high temperature synthesis able to impart strong metal-support interaction, besides high thermal resistance [1]. Ethanol conversion, selectivity to the main possible byproducts and the CO/CO2 ratio, as a measure of the contribution of the water gas shift reaction, were correlated to the temperature, water/ethanol ratio and space velocity in a central composite experimental design [2]. Two different bioethanol samples, 50 and 90 vol%, produced and supplied by a company (Mossi&Ghisolfi), have been used for at each temperature. Attention was paid to the catalyst resistance towards deactivation by coking.
The kinetic expression was implemented in a software simulation (Aspen Plus), designing a high pressure reactor. A successive process design was investigated considering the hydrogen purification section as well and evaluating the economic feasibility of different plant configurations and operative conditions. Net plant efficiencies and total capital investment will be estimated as well as internal rate of return and payback period.
[1] M. Compagnoni, J. Lasso, A. Di Michele, I Rossetti*, Cat. Sci. & Tech, 6 (2016) 6247
[1] M. Compagnoni, A. Tripodi, I. Rossetti*, App. Cat. B:Environ., 203 (2017) 899–90
Laboratory testing for lupus anticoagulants : diagnostic criteria and use of screening, mixing, and confirmatory studies
No full textThe presence of lupus anticoagulants (LA) in plasma is a strong risk factor for thromboembolism and fetal loss. Because of this, demand for testing for LA is increasing, but the performance of clinical laboratories in terms of its detection is still a matter of concern. This is due in part to the lack of specific tests but also to the lack of standardization and application of the diagnostic criteria. The aim of this article is to review the diagnostic criteria and the many issues that may affect test results. Copyrigh
Control of oral anticoagulant therapy with whole blood prothrombin time devices : the future has begun
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Laboratory tests and the new oral anticoagulants
No full textNew oral anticoagulants are ready to enter the scene on a massive basis for the treatment/prophylaxis of many cardiovascular diseases. Although they can be prescribed without dose-adjustment based on laboratory testing, the laboratory is still an essential partner that may assist clinicians for the management of anticoagulated patients. In principle, there are many tests that can be used to evaluate the anticoagulant effect of the new drugs, but the choice should be made among those that are more readily available in emergency and that are easy to run. Linearity of dose-response and responsiveness to increasing dose in addition to standardization are other important issues to consider. This article is aimed at reviewing the current tests, their characteristics and the most appropriate choice
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