[Ultrastructural study of the basal cells of the prostatic gland]

The ultrastructure of basal cell in canine and bovine prostate is studied. In the canine prostate only one type of basal cell could be specified, however in the bovine prostate type I and type II basal cells could be described. Canine basal cell and bovine type I have similar characteristic and never reach the alveolar lumen whereas bovine type II basal cell is columnar in shape, has numberous mitochondria in the apical pole and ocassionally reaches the alveolar lumen. Type II is a clearly defined intermediate cell between type I and secretory elements. All types of basal cells in both species have ultrastructural features which correspond to those of undifferentiated stem cells.

Melanotic spinothoracic schwannoma

A dumb-bell mediastinal melanotic schwannoma is described, and the rarity of this type of tumour emphasised. The tumour was resected by simultaneous laminectomy and posterior thoracotomy. The patient is well four years after operation. The pathology of the tumour is described and the origin of melanotic cells is discussed.

Subcellular distribution of rat brain cortex high-affinity, sodium-dependent, glycine transport sites

The subcellular distribution of the membrane components, present in rat brain cortex homogenates, that interact with glycine in the presence of sodium ions was studied. The distribution in the primary fractions, as per cent of total binding in the homogenate, was: P1 ('nuclear'), 58%; P2 (large granule), 39%; P3 (microsomal), 2%9 Of the subfractions obtained by centrifuging P1 in a linear 0.32--1.5 M sucrose gradient, only the lighter fraction (P1-III) formed by large myelin fragments was enriched in specific binding activity with respect to P1. The pellet formed by purified nuclei had negligible binding, and fractions of intermediate density had a lower activity than P1. Transient exposure of P1-III to 1.5 M sucrose did not diminish its binding ability. Similarly, in the subfractions obtained by centrifuging P1 in a discontinuous sucrose gradient, only the least dense one, P1-A, that is formed exclusively by large myelin fragments, was enriched with respect to P1. The electron microscopy of these fractions is presented. The P2 subfractions, obtained in a linear 2--18% Ficoll gradient, had the following sodium-dependent activity (counts/min/mg protein, fractions being in the order of decreasing density): pellet, 0; P2-I, O; P2-II, 450; P2-III, 1770; P2-IV, 4130; unfractionated P2, 880; P2-IV, the least dense fraction being composed mainly of myelin. With P2 subfractions obtained in a discontinuous sucrose gradient (0.32, 0.8 and 1.2 M sucrose layers), it was also found that sodium-dependent glycine binding was only enriched, with respect to P2, in the myelin fraction P2-A. Glycine binding to purified brain cortex myelin was also found to be very high, while binding to non-myelin membranes, obtained during the purification procedure, was only 0--7% of that seen with myelin. These results suggest that high-affinity glycine binding is located in myelin proper, and possibly also in some other glial plasma membranes, but not in nuclei, mitochondria, endoplasmic reticulum or synaptosomes. The relevance of these findings for interpreting previous reports on high-affinity glycine transport in the central nervous system is analyzed.

Quantitative electroencephalographic studies of the effects of ethanol in rabbits= I. Interaction between ethanol and reserpine

At a dose of 1 g/kg i.v. ethanol induced in the cortical EEG of rabbits a synchronization which lasted 2-3 hours. Thereafter a pronounced hyper-stimulation occurred which persisted up to 4 hours. Pre-treatment of the animals with reserpine reduced markedly the initial synchronization and abolished the delayed stimulant effect. These findings are discussed in terms of possible interaction between acetaldehyde and biogenic amines.