Is angiotensin-(3–4) (Val-Tyr), the shortest angiotensin II-derived peptide, opening new vistas on the renin–angiotensin system?

Angiotensin-(3−4) (Ang-(3−4) or Val-Tyr) is the shorter angiotensin (Ang) II-derived peptide, formed through successive hydrolysis that culminates with the release of Val-Tyr as a dipeptide. It is formed both in plasma and in kidney from Ang II and Ang III, and can be considered a component of the systemic and organ-based renin–angiotensin system. It is potently antihypertensive in humans and rats, and its concerted actions on proximal tubule cells culminate in the inhibition of fluid reabsorption, hyperosmotic urinary excretion of Na+. At the renal cell signaling level, Ang-(3−4) counteracts Ang II-type 1 receptor-mediated responses by acting as an allosteric enhancer in Ang II-type 2 receptor populations that target adenosine triphosphate-dependent Ca2+ and Na+ transporters through a cyclic adenosine monophosphate-activated protein kinase pathway

Rat vas deferens SERCA2 is modulated by Ca2+/calmodulin protein kinase II-mediated phosphorylation

Ca2+ pumps are important players in smooth muscle contraction. Nevertheless, little information is available about these pumps in the vas deferens. We have determined which subtype of sarco(endo)plasmic reticulum Ca2+-ATPase isoform (SERCA) is expressed in rat vas deferens (RVD) and its modulation by calmodulin (CaM)-dependent mechanisms. The thapsigargin-sensitive Ca2+-ATPase from a membrane fraction containing the highest SERCA levels in the RVD homogenate has the same molecular mass (∼115 kDa) as that of SERCA2 from the rat cerebellum. It has a very high affinity for Ca2+ (Ca0.5 = 780 nM) and a low sensitivity to vanadate (IC50 = 41 µM). These facts indicate that SERCA2 is present in the RVD. Immunoblotting for CaM and Ca2+/calmodulin-dependent protein kinase II (CaMKII) showed the expression of these two regulatory proteins. Ca2+ and CaM increased serine-phosphorylated residues of the 115-kDa protein, indicating the involvement of CaMKII in the regulatory phosphorylation of SERCA2. Phosphorylation is accompanied by an 8-fold increase of thapsigargin-sensitive Ca2+ accumulation in the lumen of vesicles derived from these membranes. These data establish that SERCA2 in the RVD is modulated by Ca2+ and CaM, possibly via CaMKII, in a process that results in stimulation of Ca2+ pumping activity

O sentido da vacina ou quando o prever é um dever The meaning of vaccine or when predicting is a duty

Partindo da historiografia, analisamos a construção do monumento da medicina científica: a vacina antivariólica. Ao criar e difundir a vacina, a medicina demonstra como a técnica controla a vicia em escala planetária. A grande vitória da medicina científica se funda no seguinte resultado: hoje, a existência do vírus cia varíola depende da vida em laboratório. O movimento antivacinista surge na década de 1870, na Inglaterra, e questiona a adoção universal e obrigatória da vacina antivariólica. Estudamos algumas metáforas e analogias empregadas por médicos e historiadores. Elas nos revelam o processo de construção do fato vacina.<br>From the perspective of historiography, the article analyzes the construction of scientific medicine's major landmark: the small-pox vaccine. When this vaccine was created and widely distributed, the medical field demonstrated how technology controls life on a planetary scale. The great victory of scientific medicine rests on the fact that today the life of the small-pox virus depends upon laboratory conditions. Born in England during the 1870's, the anti-vaccine movement questioned universal, mandatory small-pox vaccination. The article examines some metaphors and analogies used by physicians and historians, revealing the process by which the vaccine, as a phenomenon, was constructed