Potassium release from the rat submaxillary gland in vitro. II. Induction by parasympathomimetic secretagogues.

The kinetics of K+ release from an in vitro system of rat submaxillary gland slices were studied after stimulation with parasympathomimetic secretagogues. The slices were incubated at 37degreesC in an oxygenated, enriched Krebs-Ringer bicarbonate medium in the presence and in the absence of Ca++ and of ouabain and, in some experiments, in the presence of the specific antagonists atropine (5 x 10(-6) and 2 x 10(-5) M), phentolamine (2 x 10(-5) M) or propranolol (2 x 10(-5) M. K+ release was elicited by the addition of acetylcholine (2 x 10(-5) M), pilocarpine (2 x 10(-5) M) and carbamylcholine (10(-9) to 2 x 10(-5) M). The results demonstrate that: 1) The selective stimulation of cholinergic receptors induces a rapid net release of K+ from the slices. After 10 minutes of incubation, the percent K+ released after a 2 x 10(-5) M dose of each of the three secretagogues was, respectively, 20.8%, 15.5%, and 19%. 2) The response to carbamylcholine does not occur when Ca++ is absent from the medium and is blocked by atropine but not by phentolamine or by propranolol. Atropine (5 x 10(-6) M) causes a 17-fold shift to the right on the dose-response curve to carbamylcholine. 3) The magnitude of K+ release is the ratio of two opposing mechanisms, a passive efflux and an active reuptake. The latter depends on the activity of the ouabain-sensitive Na+-K+-adenosine triphosphatase. 4) The sensitivity of the slice system to carbamylcholine seems to be greater than that to norepinephrine in terms of net K+ release after equimolar doses of 2 x 10(-5) M and also in terms of the dose required to induce a half maximal passive K+ efflux. However, the maximal passive K+ efflux is similar after both types of secretagogue and amounts of approximately 45% of the K+ present in the slices.     

Hypertrophic pyloric stenosis in the adult

In view of the low incidence of hypertrophic pyloric stenosis, we present a case of this pathology in a male aged 74. Stenosis was of the diffuse type, associated with gastric ulcer and chronic atrophic gastritis. The patient was admitted to our Service with upper digestive tract hemorrhage after deterioration of the ulcer.     

Preliminary clinical studies of C-reactive protein quantified by enzyme-linked immunoassay

We have used an enzyme-linked immunoassay technique to quantify human C-reactive protein (CRP). In this assay phosphorylethanolamine is covalently linked to polystyrene wells. Serum or plasma specimens are diluted 961-fold and assayed. After Ca2+-dependent binding of CRP to the plates, the complex is reacted with peroxidase-labeled anti-CRP antibody. The response varies linearly with CRP concentrations between 10 and 160 mg/L; the detection limit is 0.34 ng per well. The results correlate well (r greater than or equal to 0.90) with those of rate nephelometry. This new method can be automated, is not subject to interferences or cross reactivity, is highly reproducible, has low background values, and can be carried out at room temperature.