Effect of strontium-substituted biphasic calcium phosphate on inflammatory mediators production by human monocytes.

Calcium phosphate materials are widely used as bone substitutes because of their properties close to those of the mineral phase of bones. Nevertheless, after several months, calcium phosphate-based materials release particles that may be phagocytosed by monocytes, leading to an inflammatory reaction. Strontium is well known to counteract the osteoporosis process, but little is known about its effect on inflammatory processes. The purpose of this work was to study the effect of biphasic calcium phosphate (BCP) particles substituted with strontium on the inflammatory reaction. Human primary monocytes stimulated or not by lipopolysaccharide (LPS) were exposed to BCP particles containing strontium for 6 and 24 h. Inflammatory mediators (cytokines and matrix metalloproteinases (MMPs)) production was then quantified by ELISA and zymography. We observed that the presence of strontium had few effects on unstimulated cells, but it decreased the production of pro-inflammatory cytokines and the chemokine interleukin 8 in LPS-stimulated cell-conditioned medium. This work suggests for the first time that strontium may be involved in the control of inflammatory processes following BCP phagocytosis by human monocytes.

[Echographic study in the exploration of supra-aortic trunks. Comparative study with doppler velocimetry and their respective roles in functional vascular explorations]. / Examen échographique dans l'exploration des troncs supra-aortiques. Etude comparée à l'examen vélocimétrique doppler et leur place respective dans les explorations fonctionnelles vasculaires.

Over the last six months, 1,311 doppler examinations of the supra-aortic trunks have been performed with confrontation doppler, ultrasound, arteriography and intra-operative examination according to the cases. We studied these cases with the following questions in mind: Does real time ultrasound of the supra-aortic trunks give more valuable information than the classical doppler examination? Is the diagnosis simplified? Is the therapeutic management altered? We are able to conclude: 1. In the case of a mildly stenotic plaque (less than 50%), the doppler examination gives an acoustic and graphic representation which is rich and not differentiated for stenoses of between 10% and 50%, which corresponds to an ultrasound plaque of 1 mm to 4-5 mm: the ultrasound supports the diagnosis. 2. However, in stenoses greater than 50%, there is good correlation between the doppler examination, ultrasound and arteriography. Ultrasound enables the exact extent of the plaque to be visualised in sagittal and transverse planes. It can diagnose aneurysmal lesions and suggest ulcerated lesions. 3. Finally, the doppler examination seems to be indispensable in cases of pre-thrombosis or fresh thrombosis of the carotid. Ultrasound can be negative at this early stage.