Cyclic AMP levels in cultured myocardial cells under the influence of chronotropic and inotropic agents.

In an attempt to determine whether cAMP is involved in the chronotropic and inotropic response produced by glucagon, catecholamines and prostaglandins, the intracellular cAMP levels of beating myocardial cells were determined after pretreatment with the above agents. It was found that the catecholamines and glucagon did increase cAMP levels, the order of the effect being epinephrine> norepinephrine>glucagon. The catecholamine response could be blocked by practolol, a potent β-adrenergic blocking agent. Prostaglandins E₁ and F_1α also increased cAMP levels to a similar degree to that observed with glucagon, whereas PGE₂ and PGF_2α produced no detectable effects.     

Histochemically distinct compartments in the striatum of human, monkeys, and cat demonstrated by acetylthiocholinesterase staining.

We here report observations on the distribution of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) in the striatum of the adult human, the rhesus monkey, and the cat. By the histochemical staining methods of Geneser-Jensen and Blackstad and of Karnovsky and Roots, compartments of low cholinesterase activity were identified in parts of the striatum in all three species. In frontal sections, these enzyme-poor zones appeared as a variable number of weakly stained approximately 0.5-mm-wide zones embedded in a darkly stained background. The zones varied in cross-sectional shape from round to elongated and were sometimes branched. They were most prominent in the head of the caudate nucleus. Three-dimensional reconstructions of serial sections through the caudate nucleus in the human and cat suggest that over distances of at least several millimeters, the zones of low enzyme activity form nearly continuous labyrinths.     

Esophageal strictures in children: treatment by serial balloon catheter dilatation

Grüntzig balloon catheters were used to dilate ten esophageal strictures in eight infants and children. Five infants who had anastomotic strictures following esophageal atresia repair gained complete resolution of their strictures, usually after one or two dilatations. Three older children who had strictures following esophageal re-operation or reconstruction required longer courses of dilatations to achieve consistent esophageal patency. The technique failed in two chronic strictures of two and one-half and nine years' duration. Balloon catheter dilatation, begun in the early postoperative period, is a safe, effective method for dilating esophageal strictures.