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Biomedical subjects

H Weber

Publications and source records attributed to H Weber.

At least 577 records · Page 32Linked to original sources

[Working time analysis in conservative dentistry (dental filling therapy)].

The purpose of the present paper was to determine the time required for filling therapy. The authors deal briefly with the subdivision of time adopted for the present study. Conclusions as to planning in dental practice may be drawn from the results obtained only if values determined by different dentists are available for comparison.

Dental Restoration, Permanent↗

[Alpha 1 fetoprotein in pre-eclamptic toxemia (author's transl)].

From 1973 to 1975, 287 serum levels of alpha 1 fetoprotein in women with pre-eclamptic toxemia were determined. Pre-eclamptic toxemia was classified according to modified scheme of Goecke and Rippmann. 161 patients had mild pre-eclamptic toxemia (index 1-3), 72 patients had moderate pre-eclamptic toxemia (index 4-6), 54 patients had severe pre-eclamptic toxemia (index 7). In all types of severity of pre-eclamptic toxemia more levels of alpha fetoprotein were lower or higher than the normal levels including the standard deviations. The number of abnormal values rose with an increasing toxemia index. There was no statistically significant difference between too high values and too low values. Significantly more values were above and also below the normal values. Our investigations appear to indicate that the determination of the alpha fetoprotein is not only valuable as screening method for neural tube defects but also of value in the diagnosis and management of pre-eclamptic toxemia. Too high and too low values should not be differentiated but values both above and below the normal levels should be considered.

Adolescent↗

Relationship between L-alanine and sodium ion transport in isolated renal tubules.

1. Rat renal tubules were isolated by incubation with collagenase. The Na+ concentration in the tubules at 37 degrees C was increased by additions of g-strophantin and L-alanine. The increase of Na+ in the presence of both g-strophantin and L-alanine was stronger than with either alone. 2. Radioactive sodium (22-Na), which was taken up by the tubules at 0 degrees C in K+-free medium, was more slowly washed out in the buffer with added g-strophantin than in the control buffer, but L-alanine had no effect. 3. At 0 degrees C incubation without K+, g-strophantin did not affect the 22-Na transport of the tubules. But under the same conditions, L-alanine increased Na+ uptake significantly, and in conjunction with it, L-alanine uptake was also increased. 4. The relationship between L-alanine uptake and intra- extracellular Na+ concentration gradients was linear. The ration of L-alanine to Na+ uptake at 0 degrees C was about 1:2. 5. In the incubation without K+ at 0 degrees C, L-alanine could be accumulated in tubules against the chemical concentration gradient (about 1.5-fold). 6. In the incubation without K+ at 37 degrees C, the L-alanine concentration in tubules after 5 min was already steady (Ci/Ce = 2.2), but with K+ it was not stabilized after 10 min. The ration Ci/Ce with K+ WAS HIGHER THAN WITHOUT K+. 7. G-Strophantin, p-hydroxymercuribenzoate, amiloride, and 2,4-dinitrophenol inhibited L-alanine uptake in the tubules and at the same time increased Na+ concentration. The relationship between the L-alanine uptakes inhibited by g-strophantin, amiloride and dinitrophenol, and the respective intra- extracellular Na+ concentration gradients was strikingly linear. But in the case of p-hydroxymercuribenzoate there was no correlation. 8. The results indicate that L-alanine transport into the renal tubules might be regulated mainly by the intra- extracellular Na+ concentration gradient and that inhibitors such as g-strophantin, amiloride, and dinitrophenol could have a secondary effect on the L-alanine transport which follows the change of Na+ concentration in cells. p-Hydroxymercuribenzoate might have an inhibiting effect on the binding of carrier with Na+ and/or L-alanine.

Alanine↗

[Virus-like particles in yeast protoplasts. I. Electron microscopic demonstration].

In ultrathin sections and negatively stained isolates from protoplasts of a strain of Saccharomyces cerevisiae showing abnormal morphology and degeneration phenomena the presence of virus-like particles within the cells could be demonstrated. The isometric particles have diameters of about 50 nm, the electron dense centre is surrounded by distinct envelope. Protoplastic containing up to 30,000 particles could be found. It could be demonstrated that there exists a correlation between the amount of particles and the degree of degeneration of the cellular substructure. Protoplasts with high titres of virus-like particles obviously undergo lysis. Plaque formation on agar plates could not be seen. It is concluded that the phenomena observed can be compared with cytopathological effects caused by viruses in other cell systems.

Cytopathogenic Effect, Viral↗

Effect of sodium intake on single nephron glomerular filtration rate and sodium reabsorption in experimental uremia.

Sodium balance, clearance and micropuncture studies were performed on three groups of uremic rats in which renal mass was reduced experimentally by approximately 85%. All animals received a sodium-free synthetic diet to which a measured amount of NaCl was added. Sodium intake was 3 mEq/day in one group, 1 mEq/day in a second group and 0.13 mEq/day in the third. In the latter, the Na intake was reduced (from an initial level of 1 mEq/day) as renal mass was reduced in proportion to the estimated reduction in renal mass in an effort to obviate the requirement for an increased natriuresis/nephron. Clearance and micropuncture studies also were performed in a group of normal rats maintained on 1 mEq/day of Na. All three groups of uremic rats on the standard diet maintained external Na balance. Single nephron glomerular filtration rate (SNGFR) in superficial nephrons was increased in all three groups of uremic rats and seemed to be independent of the Na intake; fractional fluid reabsorption was decreased in the proximal tubules in all three groups of uremic rats. Furthermore, absolute proximal Na reabsorption was markedly increased; and calculated values for distal reabsorption were markedly increased in all groups of uremic rats. The data suggest that the increase in SNGFR and the decrease in tubular fluid to plasma (TF/P) inulin ratios in superficial proximal tubules correlate poorly with the dictates for an increase in sodium excretion rate per residual nephron. These data also have implications regarding the operation of the control system in the regulation of external Na balance in uremia.

Animals↗

Effect of diazoxide on renal handling of sodium in the rat.

1. To assess whether diazoxide-induced sodium retention is due to a direct renal action of the durg, independent of its systemic haemodynamic effects, diazoxide was infused directly into one renal artery of hydropenic rats. During the infusion period there was a small fall in mean systemic arterial blood pressure. There were no significant changes in the clearances of inulin or p-aminohippurate by either kidney. 2. Absolute and fractional excretion of sodium were unchanged on the non-infused side. On the side of infusion, there was a significant increase in absolute and in fractional sodium excretion. 3. Thus natriuresis rather than sodium retention seems to be the direct renal effect of diazoxide and may be related to its vasodilator properties.

Aminohippuric Acids↗

The effect of delayed disc surgery on muscular paresis.

A prospective study was carried out in 280 patients suffering from sciatica caused by myelographically verified disc prolapse. The patients were divided into three groups according to the following criteria: 1. The doubtful group, selected at random. Patients with doubtful indications for surgery. Treated operatively or not--by drawing lots. 2. Non-operated group. Patients with moderate symptoms and/or continued improvement. 3. Operated group. Patients with imperative indications for surgery. The muscle strength of the lower limbs was measured during maximal isometric voluntary contractions in all the patients 2 weeks after admission. Approximately 50 per cent had paresis. Control examinations of these patients 1 year later showed that operative treatment gave no better prognosis than conservative treatment with regard to the motor function, neither in the group chosen at random nor in the selected groups. The causative factors are discussed.

Exercise Therapy↗