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The pumping action of the heart varies considerably on a beat-to-beat basis and is ultimately determined by the extent of ventricular myocyte shortening during systole. The use of isolated myocardial preparations has provided new insights about the subcellular factors that modulate power output of the ventricles.

Opioid peptides long have been hypothesized to play a role in ethanol reinforcement. Neuropharmacological studies have shown that opioid receptor antagonists decrease ethanol self-administration in rodents and prevent relapse in humans. However, the exact mechanism for such powerful effects has remained elusive. The availability of mu-opioid receptor knockout mice has made possible the direct examination of the role of the mu-opioid receptor in mediating ethanol self-administration. In the present experiments, both nosepoke and lever operant ethanol self-administration and several tests of two bottle-choice ethanol drinking were studied in these genetically engineered mice. In no case did knockout mice show evidence of ethanol self-administration, and, in fact, these mice showed evidence of an aversion to ethanol under several experimental conditions. These data provide new evidence for a critical role for mu-opioid receptors in ethanol self-administration assessed with a variety of behavioral paradigms and new insights into the neuropharmacological basis for ethanol reinforcement.

End-to-end neurorrhaphy remains the gold standard for transected nerve repair. However, the current dogma is that to be successful, nerve repairs must be tension free. Therefore, nerve gaps are most commonly repaired with grafts. While there is evidence that nerves can regenerate successfully after initial approximation under a tensile force, the amount of tension that deters regeneration of human nerves remains unclear. The present paper describes a case in which a favourable functional outcome was obtained following repair of a median nerve gap that was reduced by a dynamic tension device. The case provides some evidence that modest separations between stumps can be overcome by dynamic tension, enabling primary end-to-end repair of nerve gaps.