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Biomedical subjects

E Sorensen

Publications and source records attributed to E Sorensen.

7 recordsLinked to original sources

Minor influence of parathyroid hormone on fractional tubular reabsorption of phosphate in chronic renal failure.

In untreated patients with chronic renal failure and glomerular filtration rates (GFR) between 10 and 25 ml/min the decrease in fractional tubular reabsorption of phosphate was correlated to the degree of secondary hyperparathyroidism. This correlation was not found in patients with GFR below 10 ml/min. During treatment with 1alpha-hydroxycholecalciferol for 11 weeks: a) serum parathyroid hormone concentration decreased in all patients on average 60%, and was normal in 5 patients after treatment b) fractional tubular reabsorption of phosphate decreased significantly (on average 0.21) c) glomerular filtration rate decreased significantly (on average 27.5%). Since the reduction (or normalization) of serum parathyroid hormone concentration did not increase the fractional tubular reabsorption of phosphate, other (GFR-related) factors than parathyroid hormone play the major role for renal handling of phosphate in chronic renal failure when GFR is below 25 ml/min.

Biological Transport

Bone composition and parathyroid function in chronic renal failure.

The development of bone abnormalities has been studied in 24 patients with severe chronic renal failure. The glomerular filtration rate (GFR) was between 5 and 25 ml/min. The mean values of plasma calcium, degree of bone mineralization (P/Hypro) and bone mineral content (BMC) were subnormal, whereas the mean values of plasma phosphorus and serum parathyroid hormone (PTH) were elevated. Analysis of the data revealed that the various parameters became increasingly pathological with decreasing renal function. Serum PTH correlated inversely with both GFR and plasma calcium. The decrease in bone P/Hypro with decreasing renal function could be explained by an inverse correlation to serum PTH. Plasma alkaline phosphatase correlated inversely to both bone P/Hypro and BMC. The present study on individual patients with varying degrees of renal insufficiency shows that the development of secondary hyperparathyroidism correlates with a reduction in the degree of bone P/Hypro and suggests that significant bone changes appear when the GFR falls below 15 ml/min.

Adult

Controlled trial of 1apha-hydroxycholecalciferol in chronic renal failure.

24 patients with chronic renal failure (glomerular filtration-rate (G.F.R.) 5-25 ml/min) participated in a double-blind placebo-controlled trial of the effects of 1 alpha-hydroxycholecalciferol (1alpha-H.C.C.) 1 mug daily for eleven weeks. This treatment induced significant increases in the intestinal absorption of calcium and in plasma-calcium which reached normal levels within two weeks. It also induced a significant reduction of the raised serum levels of parathyroid hormone. No significant changes were induced in plasma-phosphorus, plasma-alkaline-phosphatase, or in the degree of bone mineralisation as measured by the phosphorus/hydroxyproline ratio in bone. The bone mineral content in the forearm measured by photon absorptiometry decreased to the same extent in the 1alpha-H.C.C. groups and in the placebo group. The fall in G.F.R. over eleven weeks was 2-5 times greater in the 1alpha-H.C.C. group than in the placebo group, but this difference was not significant. It is concluded that 1alpha-H.C.C. treatment in chronic renal failure does not affect the progressive loss of calcium from bone despite normalisation of plasma-calcium.

Adult

Toxicological problems with the REDY system.

Dialysate from the REDY dialysis system was examined for toxic elements, special attention being paid to the content of zirconium and aluminium. Also investigated was the concentration of formaldehyde in the rinsing fluid of three consecutive washings. The amount of zirconium and aluminium found in the dialysate was negligible. The concentration of formaldehyde was alarmingly high after two consecutive washings, a considerable amount (less than 50 mg) still remaining after three washings. It is recommended that at least three consecutive washings be performed, and that, if possible, formaldehyde be substituted by another antiseptic. Of special interest was the finding of a very high concentration of boron in the dialysate. It is suggested that this metal, which is a potentially toxic substance, may emanate from the patient. It is concluded that use of the REDY system carries no obvious toxicological risk.

Aluminum

Granule containing cells and fibres in the sinus venosus of elasmobranchs.

The concentrations of catecholamines in the heart chambers of elasmobranchs were measured by the fluorimetric method of Bertler et al. (1958). Noradrenaline (NA) can be detected in all the chambers, but the sinus venosus is by far the richest in NA. This can either be due to the presence of storage sites for this amine in the sinus wall, or to a transport of amine to the sinus venosus from the anterior chromaffin bodies. The sinus wall contains large numbers of "granule containing cells" and axon-like processes, both with numerous dense-core vesicles of about 1800 A diameter. The dense-core vesicles contain a uranophilic matrix indicating the presence of protein, phospholipids and/or nucleic acid. The reactions failed to demonstrate amine, which may be due to a loss of amine by diffusion, to a relatively low intravesicular amine concentration, or, to the absence of amines in these granule-containing cells and processes. Heavy accumulations of granule-containing processes occur in the subendothelial area. The endothelium contains fenestrae and pores through which granule-containing fibres protrude into the venous cavity. Granule-containing cells are innervated by presumed cholinergic nerve endings. It is suggested that the granule-containing cells and fibres belong to the neurosecretory system with a cholinergic input, releasing the contents of the dense-core vesicles into the blood stream at the level of the venous cavity.

Acetylcholinesterase

Adult hypophosphatasia.

A case of adult hypophosphatasia under treatment with a high orthophosphate (P1) intake is described. The patient is a 53-year-old woman. Her symptoms have progressed for seven years, and it has been necessary to perform osteosynthesis of both crura. The diagnosis rests upon a characteristic clinical picture, low serum alkaline phosphatase activity, high urinary excretion of phosphoethanolamine, and an invariably elevated concentration of inorganic pyrophosphate (PP1) in plasma accompanied by a very high excretion of this compound in the urine. An improved technique allowed specific determinations of microquantities of PP1 in biologic materials. The concentrations of PP1 in the plasma and urine remained unchanged when the patient's intake of phosphorus was increased to 1.98 g/day. The PP1/P1 ratio in the urine was 10-20 before treatment. During treatment P1 excretion increased. PP1 excretion did not change, and the ratio decreased to around 7. The renal tubular transport of PP1 probably was saturated, and therefore PP1, which was circulating in abnormally high concentrations in the patient's fluids, could not be removed by loading with P1. Four months of treatment did not benefit the patient.

Diphosphates