Ussing's model for sodium transport across epithelia assumes the existence of two barriers in series; the outer barrier behaves as a sodium electrode and the inner barrier as a potassium electrode (Koefoed-Johnsen and Ussing, 1958); furthermore, these membranes are supposed to be independent of one another. Although experimental determinations of the changes in transepithelial potential across ...

background: acute normovolemic hemodilution is an available technique to decrease the side effects of allogenic blood transfusion. the aim of this study was to compare acute normovolemic hemodilution with allogenic blood transfusion in adult patients who were scheduled for femoral fracture surgery. methods: in this randomized controlled trial, 50 patients were randomly allocated into two equal ...

The aim of this paper is twofold. First, to describe a method for the measurement of the unidirectional flux of Na from the outer bathing solution into epithelium (J(OT)), and second, to describe the use of this method under a variety of experimental conditions in order to obtain some insight into the nature of this flux. The method developed is based on the exposure of a frog skin to a Ringer ...

UNLABELLED Inward-rectifier K channel: using macroscopic voltage clamp and single-channel patch clamp techniques we have identified the K+ channel responsible for potassium recycling across basolateral membranes (BLM) of principal cells in intact epithelia isolated from frog skin. The spontaneously active K+ channel is an inward rectifier (Kir) and is the major component of macroscopic conducta...

The interaction between caffeine and calcium on the rate of desensitization of muscle postjunctional membrane (PJM) receptors during the sustained application of 0.27 mM carbamylcholine (CARB) has been studied in vitro on the sartorius muscle of the frog. The rate of PJM repolarization with CARB added to the solution bathing the muscle or the recovery of the effective transmembrane resistance (...

Maintenance of corneal hydration is dependent on the active transport properties of the corneal endothelium. We tested the hypothesis that lactic acid efflux, facilitated by buffering, is a component of the endothelial fluid pump. Rabbit corneas were perfused with bicarbonate-rich (BR) or bicarbonate-free (BF) Ringer of varying buffering power, while corneal thickness was measured. Perfusate wa...

Local heating of the skin is commonly used to assess cutaneous microvasculature function. Controversy exists as to whether there are limb or sex differences in the nitric oxide (NO)-dependent contribution to this vasodilation, as well as the NO synthase (NOS) isoform mediating the responses. We tested the hypotheses that 1) NO-dependent vasodilation would be greater in the calf compared with th...

The output of a neuronal network depends on the organization and functional properties of its component cells and synapses. While the characterization of synaptic properties has lagged cellular analyses, a potentially important aspect in rhythmically active networks is how network synapses affect, and are in turn affected by, network activity. This could lead to a potential circular interaction...