Direct relationship between urinary prostaglandin E and sodium excretion in essential hypertensive patients

Summary Urinary prostaglandins (PGEs and PGFs), sodium and potassium were measured in 17 essentially hypertensive patients. Significant positive correlations were found between a) PGEs secreted in 24 h and sodium excreted in 24 h, b) the ratio PGEs/U_NaV before and PGEs/U_NaV after volume expansion and c) the ratio Na/K and urinary PGEs. It was suggested that renal PGEs, potent natriuretic and diuretic substances, play an important homeostatic role in the extracellular fluid regulation, and consequently in long-term control of the arterial blood pressure.     

Effects of some components ofCannabis sativa on the regenerating planarian wormDugesia tigrina

Résumé Une méthode simple d'analyse biologique des effects toxiques des substances de la série des cannainoïdes est présentée. Avec cette méthode, il est montré que les tetrahydrocannabinols 1 et 6 ainsi que le cannabidiol agissent sur le métabolisme de la sérotonine.     

Preparation of large volumes of linear gradient solutions for zonal ultracentrifugation

Résumé On décrit la construction d'un appareil à chambre close pour la préparation de gros volumes de solutions à gradients de densité linéaire. Ces solutions de sucre ou d'autres substances sont généralement utilisées pour l'ultracentrifugation zonale en gradient de densité.     

Following the signal sequence from ribosomal tunnel exit to signal recognition particle

Membrane and secretory proteins can be co-translationally inserted into or translocated across the membrane. This process is dependent on signal sequence recognition on the ribosome by the signal recognition particle (SRP), which results in targeting of the ribosome-nascent-chain complex to the protein-conducting channel at the membrane. Here we present an ensemble of structures at subnanometre resolution, revealing the signal sequence both at the ribosomal tunnel exit and in the bacterial and eukaryotic ribosome-SRP complexes. Molecular details of signal sequence interaction in both prokaryotic and eukaryotic complexes were obtained by fitting high-resolution molecular models. The signal sequence is presented at the ribosomal tunnel exit in an exposed position ready for accommodation in the hydrophobic groove of the rearranged SRP54 M domain. Upon ribosome binding, the SRP54 NG domain also undergoes a conformational rearrangement, priming it for the subsequent docking reaction with the NG domain of the SRP receptor. These findings provide the structural basis for improving our understanding of the early steps of co-translational protein sorting.