Experimental studies of apocrine secretion in the dorsal prostate epithelium of the rat

Rat dorsal prostate epithelium was studied in intact adult animals, in animals castrated for three days and in rats after inhibition of prolactin secretion. Thin sections, electron-microscopic autoradiographs and freeze-fracture replicas were used to analyze the process of apocrine secretion in this gland. The rough endoplasmic reticulum and the Golgi apparatus of the secretory cells are well developed, but secretory granules are absent. The only sign indicating release of secretory material is the appearance of blebs originating from the apical plasma membrane. Freeze-fracture replicas of the apical plasma membrane reveal that the blebs develop randomly from the bases of microvilli-like protrusions. In vitro pulse labeling of the proteins using 3H-leucine resulted in a labeling of the apical blebs. A post-castration period of three days was sufficient to reduce drastically the number and size of the apical blebs conhree weeks by application of lisuride, a synthetic ergot alkaloid, also induced regressive changes in the secretory cells. The apical blebs were still present, but they were shrunken and their content appeared condensed. These experimental conditions proved that the apical blebs are closely related to the functional activity of the cells and are interpreted as true apocrine secretion in the rat dorsal epithelium.

Inhibition and facilitation of lacrimal flow by beta-adrenergic drugs

The effects of adrenergic beta-stimulating and beta-blocking compounds on tear flow were studied in conscious rabbits with a modified Schirmer technique. The tear flow was significantly increased by the unselective beta-adrenergic agonist isoprenaline and by the selective beta1-agonist H 80/62 (racemic Prenalterol, Hässle, Sweden). The effects of the agonists were blocked by the unselective beta-adrenergic antagonist propranolol (Inderal) and by the selective beta1-antagonist metoprolol (Seloken, Lopressor). The experimental data favoured the hypothesis that the beta-receptors involved in the regulation of the tear flow were of the beta1-type. The anatomical location of these beta-receptors is at present unclear but in vitro experiments performed on the rabbit lacrimal glands indicated that the receptors were probably not located on cholinergic nerve-endings as the release of acetylcholine was not influenced by isoprenaline.

The psychotherapy of schizophrenia: Semrad's contributions to current psychoanalytic concepts

Elvin Semrad's contributions to the understanding and psychotherapy of schizophrenia are described. The author defines the principles that guided Semrad in his theoretical understanding of schizophrenic patients, and elaborates the practical application of these principles. Semrad's contributions are related to recent work by Winnicott and Kohut on the holding environment and on the self-object and narcissistic transferences. The author's formulations about the relationship of schizophrenic regressions to borderline and narcissistic personalities, and the relevance of Semrad's work to these concepts, are reviewed.

Amino acid transport in the rat exocrine pancreas. III. Effect of maximal and supramaximal hormonal stimulation in vivo

Amino acid transport and incorporation have been studied in vitro in rat pancreatic lobules after maximal and supramaximal hormonal stimulation with caerulein. Incorporation into proteins was increased already after 30 and 120 min of maximal stimulation, but was decreased after the infusion of a supramaximal dose. Uptake of neutral amino acids was monitored using labeled leucine and alpha-aminoisobutyric acid (AIB). In the case of leucine the free pool was consistently reduced after maximal stimulation, while supramaximal doses led to an increase which could be potentiated by the addition of 2mM tetracaine. Using AIB, a significant increase in the intracellular pool was observed after maximal stimulation, conversely a decrease after supramaximal stimulation. Release of labeled leucine and AIB from preloaded lobules during incubation in the cold was significantly reduced after maximal secretory stimulation, but was found enhanced by 200 to 300 percent after supramaximal stimulation. No fine structural alterations at junctional complexes or at both the lateral and luminal plasma membranes were observed after maximal stimulation except an increased number of exocytotic figures at the luminal face. However, supramaximal stimulation led to progressive rarefaction of the tight junctional network and disintegration of the gap junctions. Concomitantly, an equal distribution of membrane particles on both faces of the plasma membrane together with a random occurrence of exocytotic figures were observed.

Studies on secretory glycoproteins in the rat exocrine pancreas. III. Intracellular transport of fucose-labeled proteins as studied by cell fractionation

The transcellular movement of fucosylated glycoproteins has been studied in vitro using rat pancreatic lobules and cell fractionation procedures, and has been compared with the well established pathway of secretory proteins. Using tritiated leucine as pulse label for the latter, their translocation from the rough endoplasmatic reticulum into the Golgi complex and finally into zymogen granules could be followed. In the case of glycoproteins, 14C-fucose was incorporated mainly into the smooth microsomal fraction (representative of the Golgi complex) and only one third of this specific activity was transported into the zymogen granule fraction. A detailed analysis of this fraction after separation of the content of zymogen granules from their membranes revealed a predominant labeling of membrane glycoproteins by 14C-fucose. In comparison, leucine-labeled bulk proteins were found almost exclusively in the zymogen granule content fraction, with little radioactivity in the membrane fraction. The data indicate a concomitant synthesis of fucosylated glycoproteins destined in part for the zymogen granule membrane and to a greater amount associated with the smooth microsomal fraction. The results are discussed in the light of recent findings indicating that about 40% of the proteins in the zymogen granule membrane are made up of one major glycoprotein which could be involved in the mechanism of exocytosis.

Effect of glucagon on the secretory process in the rat exocrine pancreas

Glucagon was infused into conscious rats in doses of 10 to 80 microgram/h for periods up to 24 h. The effect on the secretory process of the exocrine pancreas was studied in vitro using isolated pancreatic lobules. A pronounced inhibition of the rate of protein synthesis and discharge of stored and newly synthesized proteins combined with increased enzyme content in the pancreas were observed after 30 min infusion. This effect was absent after longer infusion periods of up to six hours. After 12 to 24 h infusions a marked degranulation and decrease in enzyme content was observed. While the rate of protein synthesis was not significantly enhanced, both the basal and stimulated discharge of enzymes from the pancreas were increased. The results suggest a biphasic response of the pancreas to prolonged glucagon infusion.

Learning child psychiatry skills on the adult inpatient service

Integration of child psychiatry training into general psychiatric residency programs is often unsuccessful. The authors describe an innovative model of training in child psychiatry that involves the children of adult inpatients. This model offers several advantages: splitting of child-adult psychiatric training is avoided, child diagnostic and evaluative skills tend to be learned rapidly, preventive orientations develop, and family process is both learned and used. Preliminary experience with this model on two inpatient services suggests that it is both didactically effective and economical in child psychiatry staff hours.

Regulation of exocrine pancreatic secretory process by insulin in vivo

The three major phases in the secretory process in the exocrine pancreas (synthesis, intracellular transport, zymogen discharge) have been tested in vitro after changing circulating insulin levels in rats in vivo. One group of rats received a continuous infusion of glucose for periods up to 72 hours, which keeps blood glucose levels above 200 mg/100 ml and immunoreactive insulin (IRI) raised to 130 muU/ml. As a result of this treatment, amylase content in the pancreas increases by 25% while chymotrypsinogen and lipase show a comparable decrease. The rate of total protein synthesis increased by 40% after 48 hours of infusion. The basal and carbamylcholine stimulated discharge of newly synthesized proteins are not altered. The baseline discharge of amylase is increased significantly, while the discharge of lipase and chymotrypsinogen decreased below control levels. Similar results are obtained, if circulating insulin levels are raised by the application of glibenblamide (HB419) for a period of 24 hours. Protein synthesis increases by 26.5% and baseline discharge of amylase by 50%. In chronic alloxan diabetic animals the alteration of the exocrine pancreatic function depends on the severity of the diabetes and relates to circulating insulin levels. Animals with highest blood glucose levels and low or undetectable insulin concentrations show a disappearance of amylase from the exocrine pancreas and a depression of the rate of protein synthesis by 30%. The results suggest a direct effect of insulin on protein biosynthesis and zymogen discharge, most pronounced for amylase.

The effect of age on -adrenoceptor activity in tracheal smooth muscle

There was an age-related reduction of the sensitivity of rat and guinea-pig isolated tracheal smooth muscles to stimulation of beta-adrenoceptors, but the ability of tracheal smooth muscle to relax to isoprenaline was not completely lost.

Early clinical responsibility for medical students

Trends in medical education point to accelerated training in medical schools and postgraduate medical education. In a shortened curriculum, opportunities for major clinical responsibility may decrease, though it is generally acknowledged that medical students learn most effectively when given such responsibility. This paper presents the results of a questionnaire evaluating the experience of third- and fourth-year medical students who assumed major clinical responsibility on a short-term psychiatric inpatient service in a general hospital. An open-ended questionnaire was sent to the twenty-seven medical students who were on the service during the 1968–69 academic year. All but one student in each year described a positive experience in assuming major clinical responsibility. An important finding was that much anxiety and depression were present in both years, particularly in the third year. One of the implications of this study is the possibility that major patient responsibility for medical students can be successful even earlier than the third year in psychiatry and other clinical areas provided that the staff can anticipate and supportively help the students with their probably even greater anxiety and depression.