In vivo Intracellular Recording of Neurons in the Supraoptic Nucleus of the Rat Hypothalamus

Intracellular recordings were made from cells in the hypothalamic supraoptic nucleus in the urethane-anaesthetized male rat using the ventral surgical approach. Impalements lasted from 5 min to 1 h and recorded cells had an input resistance of 55 to 170 megohms. Spikes of over 50 mV were recorded from 14 cells which could be antidromically activated by stimulation of the neural stalk. The spikes showed a hyperpolarizing afterpotential and the broadening characteristic of rapidly firing magnocellular neurons, which recovered rapidly (<200 ms). When depolarized, the cells showed evidence of a transient potassium current. Recurrent synaptic coupling between the recorded cell and adjacent cells would be expected to alter the hyperpolarizing afterpotential of an antidromic spike as compared with a spontaneous spike; no perceptible difference in the waveforms of the different types of spike could be detected in 11 spontaneously active cells. Application of just subthreshold stimuli to the neural stalk did not evoke depolarizing or hyperpolarizing potentials. Suprathreshold shocks to the neural stalk, when the antidromic spike was prevented by collision, also had no discernible effect on membrane potential. Thus intracellular recordings from magnocellular neurons in vivo revealed electrophysiological properties similar to those seen in vitro. No evidence for synaptic interconnection between magnocellular neurons was found in male rats.     

Microbiological aspects of heat sterilization of drugs

International Journal of Clinical Pharmacy - In order to calculate the minimum sterilization process conditions to obtain the generally accepted sterility level (less than 1·10?6...     

Significance of changes in serum superoxide dismutase level in hypertensive syndrome of pregnancy.

The concentration of human serum superoxide dismutase-1 (hSOD-1) containing copper and zinc ions were measured by radioimmunoassay healthy nonpregnant women, 15 normal pregnant women, 15 patients with mild to moderate hypertension (MMHSP) and 15 with severe hypertensive syndrome of pregnancy (SHSP). The mean serum hSOD-1 concentration in nonpregnant women was 148.84 +/- 60.53 (x +/- s) micrograms/L; while in the other 3 groups it was 394.19 +/- 122.21 micrograms/L, 377.12 +/- 173.45 micrograms/L and 581.15 +/- 118.50 micrograms/L. The results suggest that harmful free radicals increase gradually and a strong body defence system against oxidation damage of tissue cells is produced in the course of normal pregnancy and MMHSP. With cardionatrin treatment serum hSOD-1 concentrations of patients ameliorated returned to the level of normal pregnancy. The results indicate that there is a positive correlation between cardionatrin and hSOD-1 levels (r = 0.569, P less than 0.05), and a physiological regulation of the defence system exists, which may be related to the white blood cells. Hence, hSOD-1 probably plays a significant role in defence during normal pregnancy and hypertensive syndrome of pregnancy (HSP).

     

Atrial electrophysiologic properties in paroxysmal atrial fibrillation. Study conducted with the stimulation of 5 atrial sites

Programmed atrial stimulation at five atrial sites was performed to evaluate electrophysiologic atrial properties in 17 control patients (14 M, 3F, mean age 61 +/- 9 years) (Group A) and in 18 patients with paroxysmal atrial fibrillation (13 M, 5 F, mean age 61 +/- 5 years) (Group B) with normal sinus node function. The mean value of the P wave duration was similar in both groups. Programmed atrial stimulation was performed at five atrial sites: high, medium and low lateral wall, and high and low medial wall. We evaluated the following parameters: A) local conduction delay measured at the functional refractory period as the difference between A1-A2 and S1-S2 intervals; B) widening of local electrogram measured at the functional refractory period as the difference between A1-A2 interval measured at the end of each local electrogram and A1-A2 interval measured at the beginning of each local electrogram. We evaluated the mean and the maximum value of the two above-mentioned parameters; C) dispersion of effective refractory period and functional refractory period, determined as the longest minus the shortest refractory period from the range of refractory periods measured in each patient; D) the mean of effective refractory periods and functional refractory periods observed at five atrial sites. Mean and maximum local conduction delay, mean effective and functional refractory periods did not present significant differences in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

On the way to the automated (blood) glucose regulation in diabetes: the dark past,the grey present and the rosy future

The development of the artificial pancreas represents an important step forward in modern diabetology. The practical and theoretical findings obtained by its application to Type 1 (insulin-dependent) diabetic patients has given new insights into modes of insulin secretion, pathophysiology of diabetes mellitus, and new forms of treatment, i.e. the development of portable insulin pumps and intensified conventional insulin therapy. All of these therapies provided better results than conventional insulin administration. However, there is no doubt that the restoration of normoglycaemia in a real sense is obtainable only by an implantable artificial pancreas or pancreas transplantation. The development of the implantable artificial pancreas, on the other hand, is dependent upon the development of a reliably working permanently implantable glucose sensor. The first attempts in that direction have opened new vistas as to the differences between blood and interstitial tissue glucose measurements, displaying different modes of regulation under normal and pathologic conditions. A number of barriers have to be overcome until the final goal has been attained: to obtain, by automated blood glucose control, narrow glycaemic fluctuations of the normal subject, and to prevent, hopefully, relentless diabetic complications.     

Radiological findings in 1135 edentulous patients

A sample consisting of 1135 edentulous patients with clinically healthy denture bearing areas, was examined radiologically. It appears that the diagnostic yield is high whereas the expected radiation induced risk is low. Patients should therefore be examined radiologically prior to full denture construction.     

346. Die bedeutung von stenosen an gefä\verzweigungen. eine experimentelle untersuchung an der femoralisgabel unter besonderer berücksichtigung der indikation zur profundaplastik

Zusammenfassung In einem pulsatil mit Kochsalz durchströmten Modell der Femoralisgabel wurden Flussmessungen und Druckgradienten für Flussmengen von 170 bis 860 ml/min bei peripheren Widerständen von 232 bis 25 792 dyn s cm^–5 über dem Superficialis- und Profundaabgang bei Stenosen von 1 cm Länge und Querschnittsverminderungen von 0% bis 100% gemessen. Bei grossen Flussmengen (800–860 ml/min) und kleinem peripheren Widerstand (<640 dyn s cm^–5) lag die kritische Stenose am Profundaabgang bei 4,1 mm Durchmesser, für hohe periphere Widerstände (> 5 072 dyn s cm^–5) bei 2,6 mm; bei kleinen Flussmengen (<400 ml/min) betrug der kritische Durchmesser 1,8 mm. Der nicht stenosierte Profundaabgang stellte für keine der Versuchsbedingungen ein strömungsdynamisches Hindernis dar.