Among oxysterols oxidized at C7 (7K K-, 7L L-hydroxycholesterol, and 7-ketocholesterol), 7L L-hydroxycholesterol and 7-ketocholesterol involved in the cytotoxicity of oxidized low density lipoproteins (LDL) are potent inducers of apoptosis. Here, we asked whether all oxysterols oxidized at C7 were able to trigger apoptosis, to stimulate interleukin (IL)-1L L and/or tumor necrosis factor (TNF)-K K secretion, and to enhance adhesion molecule expression (intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and Eselectin) on human umbilical venous endothelial cells (HUVECs). Only 7L L-hydroxycholesterol and 7-ketocholesterol were potent inducers of apoptosis and of IL-1L L secretion. TNF-K K secretion was never detected. Depending on the oxysterol considered, various levels of ICAM-1, VCAM-1 and E-selectin expression were observed. So, oxysterols oxidized at C7 differently injure and activate HUVECs, and the K K-or L L-hydroxyl radical position plays a key role in apoptosis and IL-1L L secretion.z 1998 Federation of European Biochemical Societies.

The ristocetin cofactor activity assay (VWF:RCo) is the reference method for assessing von Willebrand factor (VWF) activity but remains difficult to perform, and the coefficient of variation of the method is high (about 20-30%). This study evaluated and compared the performance for measuring the VWF activity of two newly commercialised assays [VWF:Ac Innovance (VWF:Ac) and VWF:RCo Acustar (VWF:RCo Acu)] with the reference VWF:RCo aggregation in 123 pathological plasma samples. The correlation and concordance between both new tests (VWF:RCo-Acu and VWF:Ac) and the reference VWF:RCo were good. The results of the VWF activity to VWF antigen ratio were also comparable whatever the method for the classification of VWF deficiency in all patients. Our results showed that both new tests could replace the "gold standard" VWF:RCo in aggregometry with several benefits: they are fully automated, easier and faster to perform, better adapted to emergency situations if necessary.

Micronucleated cell rates were assessed in cytokinesis-blocked lymphocytes of 198 male and female healthy subjects (HS) not occupationally exposed to genotoxic risks and of 70 male and female cancer patients (CP) prior to any anticancer treatment. In the HS group, spontaneous micronucleated cell rates (MN cell rates) were 9.7 +/- 2.8 per 1000 binucleated lymphocytes and 9.8 +/- 3.1 for males and females respectively. In the CP group, spontaneous MN cell rates were 21.1 +/- 15.3 per 1000 binucleated lymphocytes and 19.1 +/- 11.2 for males and females respectively. Moreover, they were shown to have a large inter-individual variability in the two groups. The study of inter-individual variation factors showed that only tobacco could affect MN cell rate in HS whereas age and sex apparently had no significant effect. In the CP group, only age significantly affected MN cell rate, whereas sex, tobacco, alcohol, imaging techniques and tumour stage had no significant effect. There was no significant difference in the distribution of gender between HS and CP, whereas there was a significant difference in the distribution of age and tobacco between the two groups. The comparison of MN cell rates in 54 HS and 54 CP matched for age and sex showed a statistically significant difference. Spontaneous MN cell rates of these two populations reflect environmental exposure. Moreover, for CP it most probably refers to various cellular lesions and genetic damage.

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