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Epidemiological studies have shown a significant correlation between increased levels of lipoprotein (a) and coronary and cerebral vascular diseases. Lipoprotein (a) presents a striking homology with plasminogen and may therefore complete with binding of plasminogen at fibrin and at the endothelial cell surface, leading to fibrinolytic system dysfunction. The aim of this work is to study the relationship between increased levels of Lp(a) and retinal vein occlusion.132 consecutive patients with retinal vein occlusion were screened for lipoprotein (a) level. They also underwent initial and final visual acuity measurement, fluorescein angiography and blood tests including glucose, cholesterol and triglyceride levels, apolipoprotein A1 and B, protein electrophoresis, coagulation tests. Lipoprotein (a) results were compared with those of 52 age, sex and cardiovascular risk factors-matched controls.Lipoprotein (a) values were significantly higher in the retinal vein occlusion group than in the control group (p = 0.05). Elevated lipoprotein (a) (0.1 g/l) levels were observed more often in retinal vein occlusion patients (61%) than in the controls (42%; p0.02). No correlation was found in retinal vein occlusion patients between high levels of lipoprotein (a) and a severe form of retinal vein occlusion. Lipoprotein (a) levels were similar in central vein and branch vein occlusion patients.Lipoprotein (a) has been shown to be correlated with cardiovascular disorders and may also be involved in retinal vein occlusion, probably by dysfunction of the fibrinolytic system. However, it does not seem to be a prognostic factor of retinal vein occlusion and its role has to be elucidated in further studies.

International audience; Side scan sonar is an effective tool for the localization of benthic structures over large areas. For example, it is possible to systematically cover Loch Creran (subtidal area of 9.2 km²) in 2 days, identifying details with a 10 cm resolution. Loch Creran is one of the few world sites where the tubeworm Serpula vermicularis L. constructs extensive aggregations of calcareous tubes, attaining 3 m in width. Such biogenic reefs are a high aesthetic appeal and provide an important habitat for a diverse fauna. This study explored the utility of side scan sonar in mapping reef distribution, which is necessary in view of the threat from aquaculture, bottom fishing and mooring. Using the softwares Isis Sonar® and DelphMap®, a mosaic was constructed from all sonar tracks. Moore et al. (1998) provided the bathymetric range of 1-13 m for Loch Creran reefs, which allowed us to select the potential region of presence. To perform a supervised classification using the maximum likelihood criterion, training areas were defined around known areas of reefs. Spatial analyst and Grid extensions of the ArcGIS® software were used to map serpulid reef areas. A photo-interpretation was required to generalize the interesting areas. Regions of the loch occupied by non-aggregated serpulid worm tubes, small aggregations and sparse reefs cannot be identified due to the resolution limits of the sonar equipment. However, localized modification of reef cover, caused for instance by anthropogenic damage, can be easily delimited by side scan sonar. The method facilitates the broadscale mapping of the major reef areas within the loch. It provides a faster approach to monitoring reef distribution than observational techniques such as drop-down video and diving, although such techniques are required for groundtruthing the sonar mapping. Sonar also aids in the identification of areas where quantitative monitoring of reefs is appropriate for conservation monitoring purposes.

Erythrocyte aggregation is one of the principal determinants of blood viscosity at low shear rates (low flow). Anatomical and hemodynamical characteristics make retinal venous circulation particularly dependent on hemorheological factors. Erythrocyte aggregation and other laboratory parameters (haematocrit, fibrinogen, plasma proteins, clotting) were measured in 85 patients presenting with retinal vein occlusion and 64 controls matched for age, sex and vascular risk factors (hypertension, diabetes, smoking). Statistical analysis of the results demonstrated a significant difference between the retinal vein occlusion group an the control group for erythrocyte aggregation (p less than 0.001 for the aggregation index at 10 sec and for the threshold of dissociation). The fibrinogen level, haematocrit and plasma proteins (albumin, IgA, IgG, IgM, total proteins, 2-macroglobulin) were similar in the two groups. No statistically significant difference for erythrocyte aggregation was observed between occlusions of the venous branch and occlusions of the central retinal vein or between ischaemic and non-ischaemic forms. These results suggest that raised erythrocyte aggregation mainly explains the increase in blood viscosity previously demonstrated, and could play a role in the constitution of retinal vein occlusion.