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Biomedical subjects

E Quellhorst

Publications and source records attributed to E Quellhorst.

At least 73 records · Page 4Linked to original sources

Treatment of severe hypertension in chronic renal failure by haemofiltration.

Thirteen patients with chronic renal insufficiency who had been transferred from haemodialysis to haemofiltration treatment because of dialysis and drug resistant hypertension (10 with high plasma renin activity) showed normalisation of blood pressure during a treatment period of 8 months, after which only one patient required antihypertensive drug therapy. During the first period blood pressure drop paralleled body weight loss and after 3--4 weeks blood pressure remained normal in spite of an increase in body weight. In the course of the second phase the effect of fluid withdrawal on blood pressure was directly proportional to the blood pressure at the beginning of the procedure. Adaptation of baroreceptor function must be assumed. In contrast to haemodialysis, haemofiltration did not influence the inulin space. Because of the reduced removal of small molecular substances compared with haemodialysis, extracellular osmolarity was kept stable during haemofiltration. Withdrawal of even large amounts of fluid was sustained without collapse reactions or signs of orthostatic dysregulation.

Blood Pressure↗

[Oral contraceptives, hypertension and nephrosclerosis (author's transl)].

Five personal cases and many reports in the literature demonstrate the not rare development of hypertension after oral contraceptives or an increase of an existing hypertension. In addition, the drug may also cause vascular changes in the kidneys with development of benign or malignant nephrosclerosis, similar to the increased risk of thrombo-embolic complications of the venous-arterial system. It is, therefore, necessary to check the blood pressure of women on oral contraceptive and, if hypertension exists or develops, discontinue these drugs.

Adult↗

[Correlation between sensory action potentials and vibratory perception in uremic polyneuropathy (author's transl)].

1. The sensory action potentials of the tibial nerve at the medial malleolus were studied by averaging in 51 patients with chronic renal failure treated by hemodialysis. Vibratory sense was also tested quantitatively on the dorsum of the foot with a pallesthesiometer. 2. Good correlation was found between sensory tibial nerve potentials and vibration sense in subclinical as well as in clinical uremic polyneuropathy. A biphasic potential correlated with unaffected vibration sense in 18 out of 23 patients, and impaired vibratory sense with a polyphasic response in 20 of 28 patients. Maximal nerve conduction of sensory fibres was faster (mean 37.4 m/sec) in cases with normal vibratory sense, but slower (mean 31.3 m/sec), when vibratory sense was impaired. Furthermore there was a correlation between the threshold of vibratory perception and sensory nerve conduction. 3. Sensory function, tested with conventional methods, was impaired only 5 times in 28 patients with altered vibratory perception. 4. The earlier impairment, especially of the vibratory sense, may be explained by the following neurophysiological mechanisms: a) Because of the polyphasic prolonged response of the sensory potentials, no rhythmical groups of impulses reach the central nervous system, but only a continual stream of small peaks arrives, so that vibration perception does not develop. b) A multiplication of the frequency of discharges caused by alternating firing of different sensory fibres is impossible due to the reduction of the number of axons. c) The prolongation of the relatively refractory period due to demyelinization of the surviving fibres prevents the transmission of frequent impulses. 5. Alterations of the sensory action potentials of the tibial nerve, as well as of vibratory perception tested quantitatively, are earlier signs of uremic polyneuropathy than the prolonged motor nerve conduction velocity. Since not all patients give accurate information when tests of vibratory sense are performed both methods should be applied. Physiological polyphasia of sensory action potentials and diminishing vibration perception in advanced age must be taken into account.

Action Potentials↗

[Severe side-effects during peritoneal dialysis caused by sorbitol-containing dialysate (author's transl)].

In seven patients with chronic renal failure in an advanced stage 17 episodes of upper abdominal pain, hypertension, vomiting and (in some of them) coma occurred during peritoneal dialysis with sorbitol-containing dialysate. The signs recurred in some of the patients but did not when glucose-containing dialysate of otherwise identical composition was used. Very high levels of sorbitol in CSF and serum were measured in the comatose patients. The precipitating factor is probably a reduced metabolic breakdown of sorbitol in renal failure with preferential intracellular deposition of sorbitol and subsequent cellular oedema. To avoid this dangerous reaction it is necessary to use glucose instead of sorbitol in peritoneal dialysates, despite the technical problems of sterilisation. Where this is not possible, glucose should be added in order to reduce the sorbitol concentration in the dialysate to less than 15g/l.

Adult↗

Dailysate calcium and plasma calcium fractions during and after haemodialysis.

Dialysate calcium and plasma calcium fractions during and after haemodialysis: The effect of differenct dialysate Ca concentrations on the plasma Ca fractions was examined in 28 patients. In 10 patients dialysed with a dialysate Ca concentration of 3.0 mEq/l the Ca fractions were determined at the start and end of dialysis. 8 patients were dialysed with dialysate with dialysate Ca of 3.5 mEq/l. In this group the Ca fractions were also estimated in the dialysis-free interval. The third group was dialysed with a dialysate Ca of 4.5 mEq/l. Total calcium and protein-bound calcium rose significantly in all groups. Ionised calcium in the first group was significantly reduced, in the second group it remained constant and in the third group it was significantly raised. Since parathyroid function depends on the plasma ionised calcium it is concluded that a dialysed concentration of 3.0 mEq/l is partly responsible for the pathogenesis of secondary hyperparathyroidism and of renal osteodystophy. In normocalcaemic patients a dialysate Ca concentration of 3.5 to 4.0 mEq/l is optimal. In patients entering long-term haemodialysis treatment with pronounced calcium deficiency symptoms a dialysate Ca of up to 4.5 mEq/l may be indicated for a short period after having normalized the inorganic phosphate levels in order to prevent extraosseous calcification.

Bicarbonates↗

Experimental model for peritoneal dialysis in small laboratory animals.

A simple method of performing peritoneal dialysis in rats and guinea-pigs for 48 hours is described. The method appears to be suitable for the experimental investigation of clinical problems although the long term problem of protein loss should not be forgotten when assessing the results of these short term experiments.

Animals↗

Ultrafiltration for middle molecules in uraemia.

An ultrafiltration system for the purification of toxic substances is demonstrated. Using this system, it is possible to eliminate substances with a molecular weight up to 5,000 in the same amount as smaller molecules. The clearances for smaller molecules are lower and for larger molecules higher compared to haemodialysis and they depend mainly on the ultrafiltrate flow. Amino acid loss did not exceed the amount which was eliminated by plate haemodialysers. Side effects, such as excessive haemolysis, platelet or fibrinogen depletion, were not to be found.

Amino Acids↗

Use of Tenckhoff catheter for peritoneal dialysis in terminal renal failure.

Over a period of 33 months a total of 2,146 peritoneal dialyses were carried out by means of indwelling Tenckhoff catheters in 65 patients suffering from terminal renal failure. The patients were maintained on peritoneal dialysis for periods varying from two weeks to 13 months. Treatment over long periods was possible in only a few cases. Infection and clotting, which tended to limit the functional life of the catheters, was reduced by rigid asepsis and by adding heparin to the dialysate. The Tenckhoff catheter was found to be valuable for peritoneal dialysis as a short-term measure, especially in patients in whom haemodialysis was not immediately feasible, in borderline cases when kidney function was not too seriously impaired, and as an alternative to haemodialysis when that was interrupted by complications.

Anti-Bacterial Agents↗