Search results for "dimer"

Crystallographic and (spectro)electrochemical characterizations of cobalt(II) 10-phenyl-5,15-di-p-tolylporphyrin

2021

International audience; The synthesis, cyclic and rotating disk electrode voltammograms, UV-visible absorption and Xray diffraction analyses of cobalt(II) 10-phenyl-5,15-dip -tolylporphyrin (1-Co) are described. 1-Co was crystallized by slow diffusion of n-hexane into a concentrated CH2Cl2 solution. X-ray diffraction analyses reveals porphyrin aromatic cycle stacking in the crystal, C-H•••π interactions of the CH2Cl2 solvent with the π-system of one tolyl group and Co(II)•••π (porphyrin ring) interactions. The abstraction of 1.0 F/mol during the electrolysis at the first oxidation potential was followed by spectroelectrochemistry. It leads to the Co(II) → Co(III) transformation rather than …

1993

The influence of lithium tert-butoxide (tBuOLi) and of lithium chloride on the oligomerization of tert-butyl acrylate (tBuA) initiated by tert-butyl α-lithioisobutyrate (tBiB-Li) was investigated. These additives affect both the kinetics and the product distribution. Whereas the addition of LiCl leads to a narrower molecular-weight distribution (MWD) the presence of tBuOLi induces broader MWD's, characterized by a very high fraction of the dimer. Both additives decrease the rates of propagation to different degrees. These effects are discussed on the basis of the formation of aggregates and adducts, the lithiated dimer having a higher tendency to form aggregates than the other oligomers. Th…

Red Cell Membrane Protein Lateral Mobility in Diabetes Mellitus

1992

In a group of 24 diabetics subdivided for type, we evaluated the red cell membrane protein lateral mobility marking intact red cells with pyrene-3-maleimide (3-PM) and calculating the dimer to monomer fluorescence intensity ratio (Iex/Im). The same fluorescent parameter was determined in a group of 13 normal controls. From the obtained data, it is evident that the red cell membrane protein lateral mobility clearly discriminates normals from diabetics of type 1 and 2. In normals and in diabetics of type 1 and 2 no relationship is present between this fluorescent determinant and the glycometabolic parameters (FBGL and HbA1c); considering all the diabetics, a negative relationship is evident b…

Deferral of assessment of pulmonary embolism

2007

We evaluated a simplified algorithm for safely postponing diagnostic imaging for pulmonary embolism (PE). At the index visit, patients were identified as being at high or low risk of PE; the former received full dosage low molecular weight heparin while the latter were left untreated until performance of diagnostic imaging (max 72 hours). During this period, no thromboembolic events occurred in low-risk patients (0/211, 0.% [upper 95% CI 0.9%]); only one event occurred in those at high-risk (1/125, 0.8% [upper 95% CI, 1.2]). Our study demonstrates that diagnostic imaging for PE can be safely deferred for up to 3 days.

Should we look for silent pulmonary embolism in patients with deep venous thrombosis?

2014

Background Asymptomatic or silent pulmonary embolism (S-PE) in patients with deep vein thrombosis has been the focus of numerous publications with the objective of determining the incidence of S-PE and assessing whether its existence has any clinical or therapeutic consequences that outweigh the risks associated with the diagnostic tests performed and the increased healthcare costs. The objectives were to assess the incidence of S-PE using computed tomography angiogram (CTA), to understand the epidemiological factors that might trigger embolism, and to assess whether D-dimer (DD) predicts the existence of S-PE’s. Methods A prospective and consecutive assessment of 103 hospitalized patients …

Deferment of Objective Assessment of Deep Vein Thrombosis and Pulmonary Embolism Without Increased Risk of Thrombosis

2004

Background: Treatment of patients with suspected deep vein thrombosis (DVT) or pulmonary embolism (PE) is problematic if diagnostic imaging is not immediately available. Pretest clinical probability (PCP) and D-dimer assessment can be used to identify patients for whom empirical protective anticoagulation is indicated. To evaluate whether PCP and D-dimer assessment, together with the use of low-molecular-weight heparins (LMWHs), allow objective appraisal of DVT and PE to be deferred for up to 72 hours, patients with suspected DVT and PE were prospectively examined. Methods: Patients identified with a high PCP or a moderate PCP with positive D-dimer test results received a protective full-do…

The diagnostic performance of renal function-adjusted D-dimer testing in individuals suspected of having venous thromboembolism

2019

Renal impairment, a source of chronic hypercoagulability[1][1] and inflammation,[2][2] is known to reduce the specificity of the D-dimer test in the diagnosis of venous thromboembolism (VTE).[3][3] This leads to many false positives in such patients and consequently to additional costs, as well as

Validation of the STA-Liatest DDi assay for exclusion of proximal deep vein thrombosis according to the latest Clinical and Laboratory Standards Inst…

2018

: Recommended strategy for venous thromboembolism (VTE) diagnosis includes the use of sensitive D-dimer (DDi) assays along with pretest probability (PTP) assessment. The Clinical and Laboratory Standards Institute (CLSI) recently issued a guideline (US FDA endorsed) on DDi in VTE exclusion. Such guideline specifies the ideal D-dimer assay characteristics and target population. Demonstrate STA-LiatestD-Di performance combined with a PTP score for proximal deep vein thrombosis (pDVT) exclusion in a CLSI compliant study. International, multicenter, prospective nonrandomized, noninterventional clinical outcome management study conducted in a standard-of-care setting. DDi was measured in DVT-sus…

Sex-related differences in D-dimer levels for venous thromboembolism screening.

2021

Background D-dimer is generally considered positive above 0.5 mg/L irrespective of sex. However, women have been shown to be more likely to have a positive D-dimer after controlling for other factors. Thus, differences may exist between males and females for using D-dimer as a marker of venous thromboembolic (VTE) disease. We hypothesized that the accuracy of D-dimer tests may be enhanced by using appropriate cutoff values that reflect sex-related differences in D-dimer levels. Methods This research is a secondary analysis of a multicenter, international, prospective, observational study of adult (18+ years) patients suspected of VTE, with low-to-intermediate pretest probability based on We…

Postoperative Reduction of Fibrinolysis as a Prognostic Factor of Fatal Outcome

2001

For the resection of an esophagus carcinoma a mortality rate of 2 to 30% was described, It is still unclear whether an abdominothoracic or transhiatal intervention is superior regarding the outcome. To investigate the prognostic value of fibrinolytic markers, plasmin-α2-antiplasmin (PAP) and D-dimer (DD) values were determined daily in the early postoperative period for 11days. In addition, the course of PAP and DD concentrations was compared with the method of esophagectomy. Of the 28 patients enclosed in the study, 5 died between day 10 and day 34 owing to adult respiratory distress syndrome and septicemia. The PAP and DD concentrations increased in survivors after surgery until day 5 an…