309 research outputs found
Imaging findings at the quadrangular joint in carpal boss
A carpal boss was initially described as a bony, sometimes painful mass at the quadrangular joint. Clinical examination and plain radiography will usually reveal the diagnosis. US and CT may add information. MRI may illustrate a variable bony morphology and additional bony and soft tissue pathologies. Bone marrow edema shows a significant correlation with a painful carpal boss. Hence, MRI may be of additional diagnostic value in patients with persistent pain and preoperatively. This paper presents a review of the anatomy and pathology in carpal boss. The merit of each imaging modality – in particular MRI – is mentioned
The search for the ideal thrombolytic agent
Since streptokinase and urokinase became available for clinical use, numerous attempts have been made to improve these useful thrombolytic agents. To decrease its antigenicity, streptokinase has been fragmented or coupled to human plasminogen or polethylene glycols. With a plasmin B chain-streptokinase complex a more potent agent was obtained. To prolong their half-life, streptokinase and urokinase were immobilized with water-soluble carriers. Coupling urokinase with fibrin-specific antibodies increases its thrombolytic efficacy, at least in vitro. The only thrombolytic agents with a relative fibrin specificity available for clinical purposes are tissue-type plasminogen activator and single chain urokinase-type plasminogen activator. Mutants and hybrids of these molecules are being constructed and may further improve their fibrin specificity and therapeutic potential
Density functional perturbation theory within non-collinear magnetism
We extend the density functional perturbation theory formalism to the case of
non-collinear magnetism. The main problem comes with the exchange-correlation
(XC) potential derivatives, which are the only ones that are affected by the
non-collinearity of the system. Most of the present XC functionals are
constructed at the collinear level, such that the off-diagonal (containing
magnetization densities along and directions) derivatives cannot be
calculated simply in the non-collinear framework. To solve this problem, we
consider here possibilities to transform the non-collinear XC derivatives to a
local collinear basis, where the axis is aligned with the local
magnetization at each point. The two methods we explore are i) expanding the
spin rotation matrix as a Taylor series, ii) evaluating explicitly the XC for
the local density approximation through an analytical expression of the
expansion terms. We compare the two methods and describe their practical
implementation. We show their application for atomic displacement and electric
field perturbations at the second order, within the norm-conserving
pseudopotential methods
Variations du niveau de la mer, de la température de surface et des hauteurs dynamiques le long de la côte nord du golfe de Guinée
Incidental radiological finding of a renal tumour leading to the diagnosis of Birt-Hogg-Dubé syndrome
Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal dominant condition characterised by benign tumours of the hair follicle, renal cancer, pulmonary cysts and spontaneous pneumothorax. We report the diagnosis of a BHD syndrome achieved after incidental radiological finding of a renal tumour in a 24-year old man. The patient also displayed recurrent pneumothoraces and showed to have cysts in the basis of both lungs. The association of recurrent pneumothoraces and renal neoplastic disease should alert for the possible presence of this syndrome
Role of platelet activation and fibrin formation in thrombogenesis
Further progress in the search for more effective but safe antithrombotic agents is coupled to an improved understanding of the factors involved in arterial and venous thrombogenesis. Although arterial thrombosis is initiated by formation of a layer of platelets on modified endothelium or subendothelial constituents and subsequent recruitment of passing-by platelets, this phenomenon is not sufficient to lead to a full thrombus. Further growth of such a platelet mass depends, to a large extent, on the presence of free thrombin. Thrombin is mainly generated by activation of factor XI on the platelet contact with collagen. In addition, thrombin leads to formation of fibrin, which maintains the stability of the arterial platelet thrombus and is the main component of the venous thrombus. The search for agents that inhibit platelet activation and thrombin formation is, therefore, a logical endeavor
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