A comparison of hepatitis A and hepatitis B measures among vaccinated and susceptible online men who have sex with men.

Hepatitis A virus (HAV) and hepatitis B virus (HBV) continue to be major health concerns among men who have sex with men (MSM). The Internet both facilitates high-risk sexual encounters and provides opportunities for promoting healthy behaviours. This study compared self-reported HAV and HBV vaccination levels, based on demographics, health characteristics, hepatitis knowledge, attitudes and risk behaviours among MSM using an online survey posted from February through June 2005. Each participant (n = 968) reported whether they were vaccinated, infected or susceptible for hepatitis A and/or for hepatitis B. Men whose health-care provider recommended vaccination were 12.91 (95% confidence interval [CI] 8.11, 20.55) times more likely to be vaccinated against HAV and 17.93 (95% CI 10.82, 29.70) times more likely to be vaccinated against HBV than those at risk of infection, respectively. These data provide essential information for public health professionals to successfully promote vaccination among members of this population.

Composition and dynamics of plasma in Saturn's magnetosphere.

During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.

Reconstitution of an endosome-lysosome interaction in a cell-free system.

A cell-free model for the transfer of endocytosed material to lysosomes is described. Rat liver late endosomes, loaded in vivo with radiolabeled ligand by intravenous injection shortly before killing the animal, showed a specific interaction with lysosomes when incubated at 37 degrees C in the presence of cytosol and an ATP regenerating system. The location of the ligand, generally asialofetuin, was analyzed by isopycnic centrifugation on Nycodenz gradients. Appearance of radiolabel in the lysosomal position on such gradients was maximal after approximately 30 min at 37 degrees C and required the provision of undamaged cytosol, lysosomes, and an ATP regenerating system. It could not be accounted for by nonspecific bulk aggregation of membranes. Transfer occurred only from late endosomes; radiolabel in early endosomes was unaffected. Digestion of the asialofetuin, as shown by the appearance of TCA-soluble radioactivity, occurred on incubation at 37 degrees C and was increased by the provision of an ATP regenerating system.

Effect of beta adrenergic blockade on renin response to renal nerve stimulation.

The ability of d,l-propranolol to block renin secretion in response to various extrarenal stimuli, such as hemorrhage and hypoglycemia, has been interpreted to indicate the presence of an intrarenal beta receptor regulating renin release. However, two problems complicate this interpretation: (a) the stimuli have effects outside the kidney, and (b) d,l-propranolol has a local anesthetic, as well as a beta adrenergic blocking, action. In the present study, the effects of a purely intrarenal stimulus, in the form of renal nerve stimulation (RNS), on renin secretion was examined. The effects of d,l-propranolol (anesthetic and beta-blocking activity), l-propranolol (beta-blocking activity only), and d-propranolol (local anesthetic activity only) on the renin response to RNS were examined. In a control group of animals, two sequential RNS increased mean renin secretion from 401 to 1,255 U/min (P less than 0.25) and from 220 to 2,179 U/min (P less than 0.01). In a second group the first RNS increased renin secretion from 201 to 1,181 U/min (P less than 0.01), but after d,l-propranolol was given RNS did not significantly alter renin secretion (33 to 55 U/min). In a third group the initial RNS increased renin secretion from 378 to 1,802 U/min (P less than 0.025), but after l-propranolol was given RNS had no significant effect on renin secretion (84 to 51 U/min). A fourth group of dogs showed a rise in renin secretion from 205 to 880 U/min (P less than 0.001) in response to the first RNS, while the second RNS, given after an infusion of d-propranolol, caused a rise in renin secretion from 80 to 482 (P less than 0.005). The nature of the electrical stimulus was consistent in all groups and caused no detectable changes in renal or systemic hemodynamics or in urinary electrolyte excretion. The results, therefore, indicate that renin secretion can be stimulated through intrarenal beta receptors independent of changes in systemic or renal hemodynamics or in tubular sodium reabsorption. Hence the effect of beta stimulation on renin secretion would appear to result from a direct action on the renin-secreting cells of the juxtaglomerular apparatus.