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The effects of the new, orally administered converting-enzyme inhibitor, enalapril (MK-421), were studied in 12 ambulatory patients with severe cardiac failure who were also receiving digoxin and diuretic agents. The study was double-blind, parallel, placebo-controlled and randomized. The clinical characteristics and pretreatment exercise performance were similar in the two groups of patients. All vasodilator drugs had been withdrawn two weeks before the start of the trial. At 12 weeks, the patients receiving enalapril showed a significant improvement in the functional class of the disease, exercise time (P less than 0.01), and maximum workload achieved, and experienced relief of symptoms. Blood pressure fell in patients receiving active treatment suggesting a reduction of afterload. Left ventricular ejection fraction was unchanged in enalapril-treated patients, but fell in patients on placebo (P less than 0.001). Enalapril was well tolerated without apparent adverse effects. It was effective when used with digoxin and diuretic agents in the treatment of severe cardiac failure, and its efficacy was maintained throughout 12 weeks of therapy.

The hundred and fifty-seven ultrasonographic examinations were carried out in 200 patients with testicular tumour. In 16 cases (8.0%) liver metastases were demonstrated. There were three main patterns: well- or ill-defined echopoor lesions, well-defined echogenic lesions, and "target" lesions. Echopoor liver lesions were found in metastatic seminoma, whilst metastatic teratoma may give any of these three patterns. The value of ultrasound for evaluating the therapeutic response of hepatic metastases from testicular tumour is discussed.

In hypoxia, but not normoxia, alpha-tocopherol (vitamin E) acts as an agonist in guinea-pig isolated colon, producing dose-dependent increases in contractile activity. This effect is mimicked by agents, vitamin K1 and phytol, which contain a structural similarity to the phytol side chain of alpha-tocopherol, but is antagonized by vitamin K3 which has a structure similar to the chromane ring of vitamin E. All of the agonist responses were blocked by atropine and potentiated by physostigmine but were unaffected by hexamethonium. However, responses to acetylcholine were not antagonized by vitamin K3 and these data suggest that alpha-tocopherol, phytol, vitamins K1 and K3 may be acting on a 'hypoxia receptor' which mediates release of acetylcholine onto muscarinic receptors.

Extracellular potentials were recorded in the pineal gland of urethane-anesthetized rats. Two distinct populations of excitable pineal "cells" were found, the silent "cells" which were driven by habenula stimulation and the spontaneously active cells. In the former case 17 of the responses (median latency of 1.2 ms) showed a positive-negative potential, and 6 (about 1 ms latency) showed only positive potential of 1-2 ms duration. The remaining cells (114), which could not be driven by habenula stimulation, exhibited spontaneous activity with a firing frequency from less than 1 Hz to greater than 100 Hz with a median firing frequency of 10 Hz. These experiments clearly demonstrate a direct habenulo-pineal fiber pathway and furthermore show that there are neuronal elements in the pineal which are only activated by habenula stimulation.