Increased ß2-adrenergic vasorelaxation at the early phase of endotoxemic shock in rats.

BACKGROUND AND PURPOSE: The early management of the cardiovascular dysfunction of septic shock is critical as it is associated with a poor outcome. Although the use of catecholamines is a common therapy in this syndrome, no data are available on the involvement of ß-adrenoceptor (ß-AR) subtypes and only few studies report an alteration of ß-adrenergic-induced vasodilation in septic shock. The purpose of the study was to evaluate vascular ß1, ß2 and ß3-AR expression and function in an endotoxemic rat model. EXPERIMENTAL APPROACH: Endotoxemia was induced in rats by intravenous injection of lipopolysaccharide (LPS). ß1, ß2 and ß3-AR mRNA expression was evaluated by RT-PCR in aorta and vascular ß1, ß2 and ß3-AR responses were determined on conducting (aorta) and/or resistance (mesenteric and renal) arteries by constructing relaxation curves in response to different ß-AR agonists. RESULTS: The maximal effect of isoproterenol decreased by 31 to 61% in the three vascular beds of LPS-treated rats compared to controls. In aortas from LPS-treated rats, ß1 and ß3-AR mRNA expression was decreased and associated to a reduced ß1 and ß3-induced vasodilation. Conversely, albeit ß2-AR mRNA was unchanged, the maximal ß2-AR-induced vasodilation increased by 49% in aortas from LPS-treated rats compared to controls. This increase was not affected by endothelium removal but was abolished in the presence of a ß2-AR antagonist or an adenylate cyclase inhibitor. CONCLUSIONS: In endotoxemia, ß2-AR vasodilation was increased by a potential recruitment of ß2-AR located on smooth muscle cells. This study suggests that vascular ß2-AR should be a putative new therapeutic target in septic shock.

Oriented macroporous polyacrylamide gels.

Macroporous gels with huge cavities and partition walls result from controlled microsyneresis during gelation. In this report we show that the microsyneresis process can be further controlled: it is possible to orient the partition walls of macropores by the use of an electric field throughout polymerization. Our oriented macroporous polyacrylamide gels offer a specific structure: a set of parallel channels of about 2 microm inner diameter, with polyacrylamide walls including acidic groups linked to the aggregated matter.

Computerized analysis of food records: role of coding and food composition database.

Reported dietary intake records of 30 subjects (26 men and 4 women) were analysed by three different centres using their own computerized nutrient database systems. The agreement between systems was evaluated by different statistical criteria (the correlation coefficient, the mean difference and the proportion of individuals placed in the same thirds of distribution). Significant differences between the three systems were found in the calculation of alcohol, polyunsaturated fatty acids, saturated fatty acids, linoleic acid, linolenic acid, cholesterol, magnesium, sodium and water. To ascertain the extent of mean differences that could be attributed to the coding process or to the database used, coding forms of each centre were forwarded to the other two centres. Analysis of variance showed that differences in the data obtained by the three systems were mainly due to the food composition database used.

Chloropicrin formation during oxidative treatments in the preparation of drinking water.

Chlorination of water can lead to the formation of chloropicrin. The numerous potential precursors (of various reactivities) observed during this study, confirm this hypothesis. Combination of ozonation and chlorination can also lead to the formation of this compound, dangerous to health; however, the conditions of the formation and particularly the impact of a nitration reaction in the gas phase are still not clearly defined.