Regional net uptake of 14C-glucose by rat brain under the influence of corticosterone

Fifteen seconds after intracarotid injection of either 14C-glucose or tritiated water in adrenalectomized rats, the net uptake of the respective tracer by 18 brain regions and by the anterior pituitary was measured. Corticosterone added to the injection solution (1 or 100 micrograms ml-1; 0.2 ml per animal) caused a dose-dependent decrease of net uptake of 14C-glucose in twelve regions. Compared to the net uptake of tritiated water which was used as a measure of relative blood flow, it suggests that this effect, at least partially, is due to a decreased blood-brain barrier permeability to 14C-glucose. Furthermore, the regional net uptake of 14C-glucose was estimated in rats with different endogenous corticosterone levels but injected with an identical solution in each case. Statistically significant differences could be observed between adrenalectomized and restrained animals in three brain regions.

[High altitude retinal hemorrhages in mountain climbers (author's transl)]

A report is given on three patients who noticed an acute deterioration of visual acuity after a sojourn at 5000 altitude caused by retinal hemorrhages. We documented both the ophthalmological examinations such as visual acuity, fundus, perimetry and fluorescence-angiography and the systemic results. During the period of about half a year after the incidence of deterioration of visual acuity we followed the course of illness. The pathophysiological mechanism, and therapeutical and prophylactical possibilities are discussed in consideration of the results of other authors.

Influence of changes in composition of the cerebrospinal fluid on the secretory activity of the subcommissural organ in Rana esculenta. A quantitative histochemical and autoradiographic study by means of scanning cytophotometry

The effects of injection into the brain ventricle of noradrenaline dissolved in amphibian Ringer's solution, and of amphibian Ringer's solution alone on the secretory activity of the subcommissural organ (SCO) of Rana esculenta were studied. The parameters used were: the amount and mean concentration of secretory material within the SCO stained by aldehyde fuchsin (AF), the amount and mean concentration of radioactive material within the SCO labelled by 35S-cysteine, and the growth rate of the Reissner's or liquor fibre (LF). A significant influence on the amount of secretory material in the SCO was found to be exerted by the injection of amphibian Ringer's solution alone. This influence can be explained as an inhibition of the release of secretory material by the SCO. Injection of noradrenaline dissolved in amphibian Ringer's solution appeared to have a smaller inhibitory effect. Noradrenaline may be presumed to have only slightly stimulated the secretory activity of the SCO.

[Effect of oxytocin on regional 3H-orotic acid uptake in rat brain]

The uptake of the RNA precursor [3H] orotic acid by 18 brain regions of male rats was measured after intracarotid injection and a survival time of 15 s. Ocytocin added to the injected solutions (final concentrations: 1 to 1000 mU/ml) caused a dose-dependent enhancement of tracer uptake by 11 areas. Some of these regions (e.g. hippocampus) are thought to be involved in the behavioral effects of vasopressin and other peptide hormones (Van Wimersma Greidanus et al., 1975 a). Results of experiments in which the net uptake of tritiated water was used as a measure of relative blood flow led us to the conclusion that the blood-brain barrier permeability to [3H] orotic acid rather than the cerebral blood flow is changed by ocytocin. The present results support the assumption that the enhanced precursor supply caused by ocytocin might contribute to the influence of this peptide hormone on memory consolidation.

[The salivary fluoride level after administration of fluorides and fluoride complex salts]

Compounds of fluorine and Si or Fe are found in nature and are sometimes formed from F ions in the stomach. The chemistry of the release of resorbable F ions from such compounds in the intestinal tract is described. To demonstrate fluorine availability at the enamel surface daily profiles of fluorine concentration in the saliva of seven subjects after a single administration of a NaF and Na3FeF6 tablet are presented and their effect on the remineralization of the dental enamel described.

[Hydroxy-ethyl-starch as plasma substitute in transurethral prostatectomy with the "cold-punch" method (author's transl)]

Each of 24 patients undergoing transurethral prostatectomy under spinal anaesthesia received 1000 ml HES and, depending from the clinical situation, some patients received blood-transfusion. Afterwards two groups were formed: group A (11 patients), who received HES only, and group B (13 Patients) with additional blood-transfusions. The following parameters were monitored simultaneously: blood pressure, heart rate, stroke index, cardiac output, active blood volume, hemoglobin and hematocrit in whole blood as well as in the irrigatin fluid of the bladder. They showed HES to be a useful plasma substitute for older patients. It is well tolerated and has a slow stabilising effect on circulation, which was effective for several hours. Furthermore, HES-infusion reduced the average need of bloodtransfusion by 500 ml.

Longitudinal investigation of changes in interviewing performance of medical students

The purposes were to determine the direction and extent of change in a medical student's ability to relate to patients between the sophomore and senior years, to assess the degree of predicted senior year performance from the sophomore year, and to determine the reliability of two major methods: interaction analysis (IA) and global faculty ratings. Twenty-two students were video-taped conducting two 10-minute interviews with a programmed patient: one as a sophomore, the other as a senior. The results for the interaction analysis method showed that the students were more directive, used more exploratory behaviors, were less supportive and more highly rated by the patients (actors) in the senior year. The physician-evaluators' global ratings indicated the students were more supportive, empathetic and open-ended, had fewer uncommon words, but conducted better overall interviews as seniors. The IA method was more reliable than global faculty ratings.

[Dental plaque pH in patients with hereditary fructose intolerance]

There is little doubt that the initial cariogenic attack upon dental enamel is caused by acids stemming from metabolic activity of dental plaque microorganisms fermenting carbohydrates. However, a direct correlation between caries activity and pH changes of plaque has not yet been established. In-vio and in-vitro plaque pH was recorded in 4 caries-free HFI children by the method of Graf, R., and Graf, H. Application of 10% glucose were followed regularly by pH drops from the fasting range pH 6.2-7.2) reaching values of 4.7 to 6.5 after 20 minutes. These were comparable to values found in normal subjects. 10% sucrose treatment resulted in a slower and less pronounced pH lowering, reaching a pH between 4.8 and 6.5 compared to normal control subjects, which showed the classical drop down to pH 4.0 to 4.3 The results indicate that human dental plaque grown under sucrose- free conditions cannot metabolize sucrose (or its initial breakdown produce fructose) to produce an in-vivo pH drop below the critical range of enamel demineralization. The zero caries activity of the children may be explained by the lack of a demonstrable classical pH drop or acid attack.

Review of current methods for the detection of Trichomonas in clinical material

Methods of ;wet preparation', stained films, and culture were used to detect trichomonads in vaginal exudate and the results of these methods are compared. A method using a wet preparation and Oxoid no. 2 Trichomonas medium is reliable for routine use.

Observing behavior in the squirrel monkey in a situation analogous to human monitoring

Observing and detection behavior were examined in four squirrel monkeys under schedule conditions similar to those employed in human monitoring experiments. Observing responses produced either a visual signal ( Sd) indicating availability of food reinforcement for an instrumental (detection) response or an SΔ indicating non-availability of reinforcement. Signals were terminated by a detection response and followed by reinforcement. SΔ exposures in the absence of signals were 0.5 sec. in duration. Detection responses in SΔ had no consequence. Signal availabilities were programmed according to random interval schedules. Mean intersignal availability times of 1, 2, 4, and 8 min. corresponding to average signal rates of 60, 30, 15, and 7.5 per hour were examined in that order. All schedules used generated a constant high rate of observing responses with short detection latencies in the presence of signals and very few detection responses in the absence of signals. No decrease in observing rate or increase in detection time was obtained within 2-hr. sessions. Neither observing rate nor detection latency varied systematically as a function of signal frequency. Distributions of observing inter-response times in the absence of stimuli were random except in one animal. Results are discussed in relation to data from other experiments on operant behavior.