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Biomedical subjects

C Fuchs

Publications and source records attributed to C Fuchs.

At least 91 records · Page 5Linked to original sources
PubMed1977

[Surgical aspects of secondary hyperparathyroidism (author's transl)].

During long-term dialysis of patients in chronic renal failure disorders of mineral metabolism in the sense of renal osteodystrophy occur increasingly with time. Quite separate from these patients with renal osteopathy (osteomalacia and osteopenia) as a result of dialysis there is a group of patients in whom, despite appropriate dialysate composition, a full-blown picture of renal osteodystrophy due to secondary hyperparathyroidism develops. Subtotal parathyroidectomy will significantly improve them. Experience in 12 patients has demonstrated that, in addition to the clinical signs, biochemical findings and radiological changes, the quantitative evaluation of iliac crest biopsy and determination of parathormone and ionised serum-calcium fraction are decisive as indications for surgery. In these patients subtotal parathyroidectomy gave satisfactory results, but the treatment of renal osteopathy in the sense of osteopenia is often unsatisfactory and the full clinical picture can often be improved only by early renal transplantation.

Adult↗
PubMed1977

Effect of dialysate calcium concentration on plasma parathyroid hormone during hemodialysis.

The effect of changes in the dialysate calcium concentration on calcium fractions and parathyroid hormone species in plasma during hemodialysis has been examined. C-terminal immunoreactive parathyroid hormone was suppressed when plasma calcium increased by greater than 25% whereas N-terminal fragments demonstrated an increase. The significance of this is discussed in light of present knowledge of parathyroid hormone metabolism.

Adult↗
PubMed1977

Parathyroid hormone, calcium and phosphate balance in hemofiltration.

The acute changes in calcium, phosphate and parathyroid hormone have been examined in chronic renal failure patients under-going hemofiltration therapy and the results compared to a similar group treated by hemodialysis. In both groups there was a significant increase in Catot (0.32 mEq/1 for hemodialysis; 0.56 m Eq/1 for hemofiltration) with Ca++ remaining constant. Plasma phosphate and parathyroid hormone decreased during hemofiltration. Calcium balances were slightly positive and phosphate balances distinctly negative in all cases. To date there is no indication of induced osteodystrophy during hemofiltration therapy, although long-term studies are needed. However, the present results indicate, that hemofiltration more closely approaches the physiological situation than conventional hemodialysis.

Calcium↗
PubMed1976

Comparative calcium ion determinations in plasma and whole blood with a new calcium ion analyzer.

A new Ca2+ analyzer has been used for the determination of Ca2+ in plasma and whole blood from normal subjects and patients with disorders of calcium metabolism. The results were nearly identical: the equation of the regression line was y=1.02x-0.037 and the coefficient of correlation r=0.998. The possibility of using whole blood for measurement with concomitant simplification of the anaerobic sample preparation is an obvious advantage.

Calcium↗
PubMed1975

Fluoride determination in plasma by ion selective electrodes: a simplified method for the clinical laboratory.

A potentiometric method for the determination of fluoride (F-) in serum and plasma is proposed; it is based on a combination of the single-known-addition method and the electrode slope-by-dilution method. This procedure provides reliable results in extremely low measuring ranges down to 2.5 mug/l, where the electrode slope deviates markedly from Nernstian behaviour. In this method no electrode calibration is required and only one standard is necessary. 1 ml of plasma is sufficient for one analysis. Apart from a 5% enrichment of all samples with a concentrated total ionic strength adjustment buffer, no further preparation of the sample is required. The simplicity of the various pipetting and analytical steps, and also of the evaluation of the readings, may render this method highly suitable for the clinical laboratory. Investigations into the accuracy and precision of the method produced satisfactory results. The recovery in plasma amounted to 99.7%, even in the low measuring ranges. The discrimination capacity of the method amounts to 0.1 mug/l. With the apparatus and experimental procedures described, 18 plasma analyses per day can be performed even at low F- concentrations with which longer electrode stabilization periods are required. Storage of the plasma samples frozen at --20 degrees C for up to 8 weeks exerts no effect on the F- concentration. Problems of sample contamination and other disturbances are discussed. Determinations of normal values in 20 test subjects resulted in a mean value of 10.4 plus or minus 4.01 mug/l (Mean plus or minus S.D.). The modal value amounted to 9.5 mug/l, and the range was between 5.9 and 18.8 mug/l. The F- content of the drinking water supplied to this group of persons amounted to 180 mug/l. The importance of the method has been illustrated using a clinico-nephrological study as an example.

Adult↗
PubMed1975

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↗
PubMed1975

Pulse-radiolytic investigations of catechols and catecholamines. I. Adrenaline and adrenochrome.

Adrenaline (epinephrine), adrenochrome and C4-substituted catechol model compounds were pulse-irradiated in aqueous neutral and alkaline solutions. Transient spectra are reported after oxidizing adrenaline and reducing adrenochrome. All species appearing during 20 msec interval after the pulse have been identified: the OH adduct with an absorption maximum at 300-310 nm, the semiquinone (at 245 nm), and adrenaline quinone (at 340 nm). The reaction of superoxide anions (O2-) with adrenaline was less efficient, compared with OH radicals. A novel oxidation product, derived from the semiquinone and O2-, has been identified as the 4-hydroxy-3,6-dioxo derivate. The pulse-radiolytic reduction of adrenochrome by hydrated electrons (eaq-) yielded the semiquinone of adrenochrome (absorbing at 470 nm), which subsequently decays by a second-order process. The dismutation products leuco-adrenochrome (absorbing at 300 nm, pH 9-8) and the adrenochrome tautomer (absorbing at 375 nm) are unstable, forming 5,6-dihydro-N-methyl indole and regenerating adrenochrome.

Adrenochrome↗