Bacterial colonization of human urethral mucosa. I. Scanning electron microscopy.

A scanning electron microscopic investigation of the urethral mucosa of altogether ten men and women subjected to cystourethrectomy because of urothelial cancer of the urinary bladder was performed. The mucosal cells were found to be polygonal and characterized by the presence of microvilli and microridges. No sex difference could be demonstrated. Although a higher number of cells carrying microridges was found in the proximal part of the urethra, no statistical difference in the number of cells with various surface topography was found in different parts of the urethra. The micrographs revealed that the number of urethral cells to which bacteria were attached, was low, also in patients with proven preoperative infection. The bacteria, mainly cocci, seemed to exhibit a preferential adherence to a subpopulation of urethral cover cells, as indicated by the observation that the organisms were not attached randomly. The possibility that different cell surface properties may explain this distribution is considered.

Catecholaminergic innervation of muscles in the hindgut of crustaceans. An ultrastructural study.

The crustacean species Pacifastacus leniusculus and Gammarus pulex were investigated by electron microscopy in a search for possible neuromuscular junctions in the hindgut, which has a rich supply of catecholaminergic fibres. True neuromuscular synapses were found in both species between nerve terminals containing dense-core vesicles (80-110 nm in diam.) and muscle fibres. We suggest that the dense-core vesicle terminals contain a catecholamine, and this is supported by ultrahistochemical tests for monoamines. Two types of junctions are found: one in which the nerve terminal is embedded in the muscle cell (both species) and one in which protrusions from the muscle cell meet nerve terminals (Pacifastacus). Gammarus pulex, which has only circular muscles in the hindgut, has only catecholaminergic innervation, whereas Pacifastacus leniusculus has circular and longitudinal muscles both with at least two types of innervation.

Evidence for new catecholamines or related amino acids in some invertebrate sensory neurons.

In certain sensory neurons of many different invertebrate species, including the sea anemones. Metridium senile and Tealia felina and the crustacean Artemia salina, fluorophores are formed during the course of the fluorescent histochemical technique of Falck-Hillarp. The presumed catecholamine nature of the neuronal fluorogenic compound was investigated by microspectrofluorometry, and the spectral characteristics of the fluorescence in the taxonomically different species was found to be very similar (excitation maximum at 375 nm with a smaller peak or shoulder at 330 nm and sometimes a shoulder in the spectrum at 410 nm; emission maximum at 475 nm). The emission maximum coincides with that of the catecholamines and DOPA (475 nm). The excitation maximum (375 nm) directly after formaldehyde treatment, however- differs from that of the catecholamines and DOPA (410 nm), but is similar to the excitation maximum displayed by these catechol derivatives at acid pH. The spectral characteristics of the fluorophore in the sensory cells might therefore theoretically be explained by an acid pH in the cells. This means improbable, however, and it is suggested that the phenomenon is due to the presence of unknown catechol derivatives. Analyses of the pH-dependent spectral changes indicate that the presumed catechol derivative in Tealia felina is beta-hydroxylated, whereas that in Artemia salina is not.

A catecholaminergic neuron connecting the first two optic neuropiles (lamina ganglionaris and medulla externa) of the crayfish pacifastacus leniusculus.

The crustacean optic neuropiles, the lamina ganglionaris and especially the medulla externa, show a specific pattern of green fluorescence with the fluorescence histochemical method of Falck-Hillarp. Normally, only the terminals and the cell bodies fluoresce, but in reserpine-treated animals exogenous catecholamines are taken up by the whole adrenergic neuron and are thus visualized as a whole. Incubating crayfish optic neuropiles in dopamine or alpha-methylnoradrenaline after reserpine treatment demonstrated a tangential neuron connecting the lamina and the medulla externa. The morphology of this tangential neuron differs from the two types of tangential neurons, Tan1 and Tan2, previously characterized with Golgi techniques. The catecholaminergic neuron thus constitutes, a third tangential neuron type.

Histochemical and ultrastructural study of prostatic tissue from baboons treated with antiprostatic drugs.

Histochemical and ultrastructural investigation of the prostate in baboons treated parenterally with saline revealed that the epithelial cells in the caudal prostatic lobe possess very high acid phosphatase activity, moderate nonspecific esterase activity and alkaline phosphatase activity, and little or no amino-peptidase or beta-glucuronidase activity. Only a few lipofuscin granules were found. Ultrastructurally, the epithelial cells had a characteristic polar appearance with a supranuclear zone dominated by large secretory vacuoles. Secretory granules were abundant in the apical zone. No clear difference was found between the cranial and the caudal prostate except that the acid phosphatase activity of the epithelial cells was much lower in the former. In baboons treated with estraumustine phosphate, diethylstilbestrol diphosphate, or with flutamide, i.e., drugs used in the treatment of advanced prostatic carcinoma, the epithelial cells in the caudal prostatic lobe showed a varying degree of atrophy, which was least in the flutamide-treated animals. The histologic changes were accompanied by only minor changes in the enzyme activities, but the number of histochemically demonstrable lipofuscin granules were substantially increased, a finding confirmed by electron microscopy. The drugs did not notably affect the cranial prostate. The findings showed that the caudal, but not the cranial, lobe of the prostate of the baboon resembles the human prostate and can be affected by drugs known to have a desirable effect on the carcinomatous human prostate.

Effect of cortisol on human fetal lung in organ culture: a biochemical, electron-microscopic and autoradiographic study.

Human fetal lung tissue obtained during the second trimester was cultured as organ culture with or without cortisol. The effect of cortisol on the phospholipid metabolism, as related to the appearance of osmiophilic lamellar bodies and the localisation of newly incorporated choline, was studied. In cortisol-treated explants, the concentration of saturated lecithins and the incorporation of (Me-3H)-choline into saturated lecithins increases significantly concomitantly with an increased number of osmiophilic lamellar bodies. The labelled choline is predominantly associated with these bodies. The obtained results indicate that cortisol accelerates the synthesis of pulmonary surfactant in the human fetal lung as early as in the second trimester.