[Endothelial dysfunction in thrombotic thrombocytopenic purpura: therapeutic perspectives]. / Dysfonction endothéliale au cours du Purpura Thrombotique Thrombocytopénique : un nouvel axe de prise en charge ?

Immune Thrombotic Thrombocytopenic Purpura (iTTP) is a rare but severe disease with a mortality rate of almost 100 % in the absence of adequate treatment. iTTP is caused by a severe deficiency in ADAMTS13 activity due to the production of inhibitory antibodies. Age has been shown to be a major prognostic factor. iTTP patients in the elderly (60yo and over) have more frequent organ involvement, especially heart and kidney failures compared with younger patients. They also have non-specific neurologic symptoms leading to a delayed diagnosis. Factors influencing this impaired survival among older patients remain unknown so far. Alteration of the functional capacity of involved organs could be part of the explanation as could be the consequences of vascular aging. In fact, severe ADAMTS13 deficiency is necessary but likely not sufficient for iTTP physiopathology. A second hit leading to endothelial activation is thought to play a central role in iTTP. Interestingly, the mechanisms involved in endothelial activation may share common features with those involved in vascular aging, potentially leading to endothelial dysfunction. It could thus be interesting to better investigate the causes of mid- and long-term mortality among older iTTP patients to confirm whether inflammation and endothelial activation really impact vascular aging and long-term mortality in those patients, in addition to their presumed role at iTTP acute phase. If so, further insights into the mechanisms involved could lead to new therapeutic targets.

Premature birth is associated with not fully differentiated contractile smooth muscle cells in human umbilical artery.

Smooth muscle cells (SMCs) participate to the regulation of peripheral arterial resistance and blood pressure. To assume their function, SMCs differentiate throughout the normal vascular development from a synthetic phenotype towards a fully differentiated contractile phenotype by acquiring a repertoire of proteins involved in contraction. In human fetal muscular arteries and umbilical arteries (UAs), no data are available regarding the differentiation of SMCs during the last trimester of gestation. The objective of this study was to characterize the phenotype of SMCs during this gestation period in human UAs. We investigated the phenotype of SMCs in human UAs from very preterm (28-31 weeks of gestation), late preterm (32-35 weeks) and term (37-41 weeks) newborns using biochemical and immunohistochemical detection of α-actin, smooth muscle myosin heavy chain, smoothelin, and non-muscle myosin heavy chain. We found that the number of SMCs positive for smoothelin in UAs increased with gestational age. Western blot analysis revealed a higher content of smoothelin in term compared to very preterm UAs. These results show that SMCs in human UAs gradually acquire a fully differentiated contractile phenotype during the last trimester of gestation and thus that premature birth is associated with not fully differentiated contractile SMCs in human UAs.

Haemodialysis and H.I.V. infection--therapeutic management.

The prevalence of human immunodeficiency virus among haemodialysis patients is of interest and this article discusses the management of 25 patients between 1985 and 1998 in Paris.

[Reiter syndrome: apropos of a case]. / Le syndrome de Reiter: à propos d'un cas.

We report the case of a 25 year-old man presenting Reiter's syndrome (urethritis, conjunctivitis and oligoarthritis). This clinical triad is a particular expression of reactive arthritis. A genital or enteric infection can be responsible for the onset. Presence of HLA B27 histocompatibility antigen is a genetic factor favoring the development of Reiter's syndrome. Many organs or systems can be affected. In addition to eradication of the initiating infection, treatment is mainly symptomatic and management is multidisciplinary.

[Ossification of the posterior longitudinal ligament]. / L'ossification du ligament longitudinal postérieur.

The authors report 4 cases of ossification of the posterior vertebral ligament. In 3 cases, the cervical spine was involved (mainly C4-C6), two included thoracic lesions. Three cases showed signs of spinal cord compression. Only one case was operated on. The authors review the literature. The authors discuss the classification, and the etiology, together with the possible relationship between the disease and ankylosing hyperostosis. Finally the pathogenesis is studied: the authors believe that spinal ischemia plays a very important role.