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We describe the design and operation of a machine that freezes biological tissues by contact with a cold metal block, which incorporates a timing circuit that stimulates frog neuromuscular junctions in the last few milliseconds before thay are frozen. We show freeze-fracture replicas of nerve terminals frozen during transmitter discharge, which display(More)
The development of new treatments for older patients with acute myeloid leukemia is an active area, but has met with limited success. Vosaroxin, a quinolone-derived intercalating agent has several properties that could prove beneficial. Initial clinical studies showed it to be well-tolerated in older patients with relapsed/refractory disease. In vitro data(More)
1. A study was made of the onset of transmission and the characteristics of transmitter release from regenerating nerve terminals in frog muscle fibres.2. Soon after transmission had been restored, some junctions were found which responded to nerve stimulation with only subthreshold end-plate potentials.3. The evoked transmitter release had a non-linear(More)
1. The extrasynaptic acetylcholine sensitivity of frog cardiac ganglion cells was measured both after denervation and during the early stages of reinnervation by preganglionic axons. Sensitivity was measured by ionophoretic application of acetylcholine (ACh) to randomly chosen sites on ganglion cell bodies. 2. Extrasynaptic sensitivity rose gradually(More)
The histological lesions were studied in seven rhesus and three cynomolgus monkeys infected with simian immunodeficiency virus for periods ranging from nine weeks to 18 months. Lymphoreticular changes included hyperplasia, follicular involution and depletion, and one animal had amyloidosis of the spleen. Hyperplastic changes also took place in(More)
1. Electrophysiological studies were made on regenerating motor end-plates in frog cutaneous pectoris muscle after crushing the motor nerve.2. The pattern of degenerative and regenerative changes is similar to that already described for the frog sartorius, although it occurs more quickly in the cutaneous pectoris. Resumption of synaptic transmission first(More)