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Biomedical subjects

H Hampl

Publications and source records attributed to H Hampl.

84 records · Page 5Linked to original sources
PubMed1979

50-S subunit from Escherichia coli ribosomes. Isolation of active ribosomal proteins and protein complexes.

A method is described for the isolation of highly purified proteins from the 50-S subunit of Escherichia coli ribosomes. All the proteins from the large subunit could be isolated with the exception of L14, L26, L31 and L34. The isolated proteins are functionally active in reconstituted particles. The method consists of successive NH4Cl/EtOH and LiCl washing steps, which split off distinct groups of proteins from the ribosome. The protein groups are further separated by a combination of gel filtration (Sephadex G-100) and ion-exchange chromatography (carboxymethylcellulose) in the presence of 6 M urea, at neutral pH and 4 degrees C. The purity of the proteins was analyzed by two-dimensional gel electrophoresis. In addition, ten protein complexes were isolated and identified.

Chromatography, Gel↗
PubMed1979

Hemodynamics during hemodialysis, sequential ultrafiltration and hemofiltration.

Circulatory parameters were determined by cardiac catheterization in patients on maintenance hemodialysis. They were studied in three groups during conventional hemodialysis, sequential ultrafiltration and hemofiltration. All three groups revealed significant reduction of cardiac output, stroke volume, pulmonary artery pressure and plasma volume. In the hemodialysis group hemodynamic parameters were unstable; specifically, hypotension, increased heart rate, and only minimal increase of peripheral resistance were observed. The other two groups showed only minor changes in circulatory parameters despite high ultrafiltration rates. Blood pressure and heart rate remained stable. On the other hand, peripheral vascular resistance increased remarkably. There is compelling evidence that during hemofiltration and sequential ultrafiltration, the patient's ability for vasoconstrictive counterregulation is better maintained than during conventional hemodialysis.

Blood Pressure↗
PubMed1979

Recirculation dialysis (RD) (20 to 40 liters of dialysate) with venous bicarbonate buffering - an alternative procedure to hemofiltration (HF).

We report about a dialysis procedure, the circulation stability of which is comparable to hemofiltration treatment. Hemodynamic parameters were measured invasively and different procedures were compared for each patient. In RD and HF significant reduction in cardiac output (HF: --20%, RD: --21.5%), stroke volume (HF: --20%, RD: --17%), pulmonary artery pressure (HF: --57%, RD: --45:6%) and plasma volume (HF: --12%, RD: --15%) were found. Blood pressure and heart rate (HF: --1%, RD: --3%) remained stable despite the high utrafiltration rate. Peripheral resistance rose significantly (HF: + 20%, RD: + 25.9%). Compared with HG, the most important advantage during RD is the improved tolerance to treatment without typical hemodialysis-induced symptoms. In comparison to that, we found under conventional dialysis an inadequate increase in peripheral resistance (HD: + 6.1%). A following strong compensatory hyperventilation with drop in PCO2 was paralleled with typical symptoms like nausea and headache. Because of resttriction of this compensatory mechanism, hypotension and arrhythmia will be induced of the following peripheral tissue perfusion and central acidosis.

Bicarbonates↗
PubMed1978

Hemodynamic studies, acid-base status and osmolality in different hemodialysis procedures.

Three patients on maintenance dialysis were each treated with three different procedures: A) twenty-liter recirculation dialysis with bicarbonate buffering, B) recirculation-adsorption dialysis and C) single-pass dialysis. Hemodynamic parameters were measured invasively and procedures A, B and C were compared for each patient. In this intraindividual comparative study, the authors attempted to establish a relationship between the varying hemodynamic parameters and the changes in osmolality and acid-base status. There were indications of some causal relationship to circulatory stability: in A and B, there were peripheral resistance increases of 24.5% and 38.4%, respectively, with stable circulation; in C, there was a 6.1% increase and unstable circulation. Additionally, the influence of acidosis is shown in B, with disproportionately strong reductions of cardiac output (21.9%) and pulmonary artery pressure (44.9%); In spite of a decrease of osmolality (A: 15.6 mOsm/L), stable circulation could be achieved if the peripheral resistance was substantially increased and acid-base status was equalized.

Acid-Base Equilibrium↗
PubMed1976

Disposition of digitoxin in renal failure.

The disposition of digitoxin was studied for a period of 8 days in 6 uremic patients given a single oral dose of 1 mg 3H-digitoxin. In plasma, the time-course of radioactivity indicated a diminished absorption velocity of tritium compared to that of control subjects already reported and, after reaching of a pseudostate-equilibrium at 24 hr, an exponential decline with a mean half-life of 8.0 days. In urine, smaller amounts of tritiated compounds were eliminated in uremic patients (8.7% of the dose) than in controls (22.5%). The average fecal excretion of digitoxin and its metabolites was not significantly increased. Chloroform extraction and thin-layer chromatography in plasma, urine and feces suggested no qualitative alteration in the metabolism of digitoxin. Calculations of the total body tritium content (body stores) after each 24-hr interval and its pharmacokinetic behavior showed that the elimination of digitoxin is determined by the transfer constant from tissue to plasma. The differences in elimination kinetics of digitoxin and its metabolites of uremic patients and healthy subjects were not significant.

Chromatography, Thin Layer↗
PubMedDate not supplied

Long-term results of total parathyroidectomy without autotransplantation in patients with and without renal failure.

The optimal surgical procedure for severe renal secondary hyperparathyroidism (sHPT) is still a point of controversy. Total parathyroidectomy (PTX) without auto-transplantation was abandoned for fear of an adynamic bone condition; however, in the case of autotransplantation recurrent sHPT is frequent and promotes atherosclerosis. We studied 11 hemodialysis patients (age 59+/-12 years) on dialysis for 18 (12-30) years in whom total PTX was performed due to severe sHPT (group I; intact PTH: 1,240+/-230 pg/ml), and 5 patients (age 55+/-10 years) without renal insufficiency who inadvertently received total PTX during thyroid surgery (group II). After total PTX (group I, 26+/-18 [9-59] months; group II, 252+/-188 [22 480] months) both groups showed no measurable intact PTH levels. Calcium homeostasis was maintained by oral substitution with calcium (group I, calcium dialysate of 2.0 mmol/l), vitamin D and calcitriol (serum parameters in groups I and II: calcium 2.4 and 2.2 mmol/l; phosphate 1.8 and 1.1 mmol/l; 25(OH)-vitamin D(3) 21 and 34 ng/ml; 1,25(OH)(2)-vitamin D(3) 32 and 41 pg/ml, respectively). In group I, after total PTX there was a rapid and sustained improvement in bone pain with markedly enhanced physical activity and endurance. High turnover osteopathy markedly improved as indicated by declining levels of native osteocalcin (90+/-17 vs. 26+/-18 ng/ml), bone alkaline phosphatase (74+/-12 vs. 12+/-6 ng/ml), and carboxyterminal cross-linked telopeptide of type-I collagen (65+/-16 vs. 40+/-21 ng/ml) but increasing levels of carboxyterminal propeptide of type-I procollagen (120+/-36 vs. 148+/-41 ng/ml). Recalcification of bone was excellent as demonstrated by X-ray and confirmed by bone histology. Itching extravascular calcific deposits and calcifications of blood vessel and cardiac valves immediately stopped after total PTX. Moreover, 6 sHPT patients suffered from severe atherosclerotic lesions such as thoracic aortic aneurysm (n = 3) or abdominal aortic aneurysm (n = 3) which showed size progression before but not after total PTX when annually controlled by ultrasonography. In group II, even long after total PTX, there was no clinical, radiological, histological or biochemical evidence for low turnover osteopathy. In conclusion, our data indicate that substitution with vitamin D(3) metabolites and calcium can prevent deleterious bone effects of hypoparathyroidism in hemodialysis patients and in patients with normal kidney function and may compensate for the missing PTH action. Over this, a better survival rate is expected as a consequence of the beneficial effect of total PTX on the progression of atherosclerotic lesions. We suggest reconsideration of total PTX without autotransplantation in dialysis patients with severe sHPT who are not eligible for renal transplantation.

Aged↗