Search PubMed⌕ Search

Biomedical subjects

D N Kerr

Publications and source records attributed to D N Kerr.

At least 127 records · Page 7Linked to original sources

Serum ionised calcium concentration: measurement versus calculation.

Four hundred and eighteen measurements of serum ionised calcium, total calcium, and protein concentrations were made from 47 normal volunteers, 104 patients with chronic renal failure (33 being treated conservatively and 71 with regular haemodialysis), and 83 renal transplant recipients. The serum ionised calcium concentration was measured with an Orion SS-20 meter and calculated from the total serum calcium and protein concentrations by using three formulae and a nomogram. In the normal subjects and patients undergoing regular haemodialysis, whose serum calcium concentrations were in or near the normal range, three of the calculations gave results similar to those obtained by direct measurement. In patients with conservatively treated chronic renal failure and those who had received renal transplants, however, there was poor aggrement between the methods. When patients with hypercalcaemia and hypocalcaemia from all the groups were considered separately there was again poor agreement between calculated and measured concentrations of serum ionised calcium. Of the patients whose measured concentrations of serum ionised calcium were high, 69-76% were classified as normal by the four indirect methods. We conclude that calculation of the serum ionised calcium concentrations is not an adequate substitute for direct measurement.

Blood Proteins↗

Osteomalacic dialysis osteodystrophy: Evidence for a water-borne aetiological agent, probably aluminium.

In patients maintained on regular haemodialysis in Newcastle upon Tyne the development of osteomalacia is substantially reduced when water used to prepare dialysate is deionised. After 1--4 years of dialysis, osteomalacia was evident in 15% of patients on deionised water in 70% of patients on softened water from the same source. The close association of dialysis encephalopathy and osteomalacia suggests a common aetiology. Both diseases occur in centres with a high tap-water aluminium content. Serum-aluminium concentrations were raised in patients undergoing regular haemodialysis in the Northern Region of England. Those using softened water had higher concentrations than those using deionised water. Patients on softened water who had encephalopathy or dementia had serum-aluminium concentrations similar to those of patients using the same water-supplies without symptoms of these diseases, but they had been treated for longer. The evidence that aluminium absorption from dialysate causes osteomalacia and encephalopathy is strong enough to justify the expense of treating water by deionisation, reverse osmosis, or both in centres where tap-water aluminium is high.

Adolescent↗

Intellectual impairment in chronic renal failure.

In a dialysis centre with a high tap water aluminium content and a known high incidence of dialysis encephalopathy, 29 patients undertaking regular home dialysis, without clinical evidence of encephalopathy, were studied with a battery of psychological tests that have proved useful in detecting early organic intellectual deterioration in other conditions. Full-scale intelligence quotient, as measured by the Wechsler Adult Intelligence Scale, did not differ significantly from that of the normal population, but the patients showed significant deficiencies in three tests of performance--namely, digit symbol, block design, and picture arrangement. The ability to acquire new information in relation to performance was impaired and the abnormality increased with time on dialysis. Such tests should be useful in early detection of dialysis dementia at a reversible stage.

Adolescent↗

Choosing the programme for an international congress.

The method of selecting abstracts for an international congress at which only 15% of submitted papers could be accepted entailed a panel of 12 assessors using their specialised knowledge, but presentation of the abstract was also important is selection. There was only a limited agreement between assessors in arranging abstracts in order of merit, so that a single assessor would be unacceptable. Use of the full panel to grade all abstracts was very expensive, but it could be replaced, without unacceptable injustice, by dividing the work randomly among groups of three selectors.

Congresses as Topic↗

Osteomalacic dialysis osteodystrophy: a trial of phosphate-enriched dialysis fluid.

To assess whether phosphate depletion is an aetiological factor in osteomalacic dialysis osteodystrophy we undertook a prospective trial of phosphate-enriched dialysis fluid, in association with oral 1alpha-hydroxycholecalciferol, for this condition. Thirty patients started the trial; of the 27 who completed more than 6 months' treatment, 14 had iliac crest bone biopsies at the beginning and end of the treatment period. Side effects included pruritus, stiffness, and increase in corneal and vascular calcification. Only one patient showed histological improvement of osteomalacia, and eight deteriorated; in seven the osteitis fibrosa worsened. Myopathy showed some improvement in four patients, but became worse in four. This treatment does not seem to have a place in the routine management of non-hypophosphataemic patients on dialysis.

Adolescent↗

Determination of serum ionised calcium by ion-exchange electrode in normal subjects.

Serum ionised calcium concentration [Ca2+] was measured with a calcium selective electrode in 65 normal people. A mean value of 1.06 mmol/l (+/- 0.04 S.D.) with an actual range of 0.97 to 1.13 mmol/l was obtained. Serum samples refrigerated at 4 degrees C for 24 h were satisfactory for analysis. Storage of whole blood samples for 6 h at room temperature before separation caused a very small error (+0.04 mmol/l). Mean results and ranges were similar in males and females and there was no significant correlation with age. No significant change in serum [Ca2+] was found following a normal meal. Serum [Ca2+] and total serum calcium showed a very slight correlation (r = 0.35). The method is reproducible and sensitive.

Age Factors↗

Hemodialysis bone disease: correlation between clinical, histologic, and other findings.

This paper explores in patients with dialysis osteodystrophy the relationship between clinical features and histological, radiological, and biochemical findings. Eighty-five patients treated by hemodialysis for more than 6 months were studied. The following conclusions were drawn: 1) Bone pain in patients on regular hemodialysis is usually a symptom of developing osteomalacia but not of hyperparathyroidism or osteoporosis. 2) Many patients with histological osteomalacia and radiological features of osteomalacia, such as fractures or Looser zones, have no symptoms. 3)In dialysis patients, biochemical and radiological abnormalities are not a reliable means of predicting the presence of osteomalacia, but a raised serum alkaline phosphatase is a good indicator of the presence of osteitis fibrosa. For early detection of osteomalacia, bone biopsy in necessary. 4)A number of our dialysis patients develop an unusual form of osteomalacia characterized by absent or minimal histological osteitis fibrosa, a normal serum alkaline phosphatase, and a high incidence of myopathy and fractures.

Adolescent↗

Congenital hepatic fibrosis: the long-term prognosis.

The long-term prognosis in congenital hepatic fibrosis has been assessed in 30 patients, 13 treated at Newcastle and 17 from other British centres. Twenty-four patients had been followed-up for more than five years from diagnosis. Shunt operations, performed in 18 patients, were successful in controlling haemorrhage with a low mortality (1/18), low incidence of recurrent haemorrhage (3/18) and portal-systemic encephalopathy (3/18) but with a higher incidence of postoperative jaundice (7/18). About a third of the survivors had some evidence of hepatic dysfunction but none had chronic portal systemic encephalopathy. Intelligence quotient was close to normal but educational achievement and job status were low. Serum albumin fell after shunt surgery and a few patients developed ascites: anaemia and hypersplenism however, were corrected by surgery. Blood ammonia is raised in survivors with congenital hepatic fibrosis and rises further after a normal meal; further observations are needed on cerebral function after several decades of survival.

Adolescent↗

Effect of 1alpha-hydroxycholecalciferol, 1,25-dihydroxycholecalciferol, 3 deoxy-1alpha-hydroxycholecalciferol, 24R, 25-dihydroxycholecalciferol and successful renal transplantation on calcium absorption in haemodialysis patients.

Using a 2-hour 47Ca absorption test, significant depression of active calcium absorption was demonstrated in 48 vitamin D untreated haemodialysis patients. This malabsorption of calcium could be corrected by the daily oral administration of 1--2 microgram of 1alphaOHD3 and 1--1.5 microgram of 1,25(OH)2D3. 5 microgram daily for 2 weeks of 3-deoxy-1alphaOHD3 AND 16 and 64 microgram daily for 1 week of 24R,25(OH)2D3 proved ineffective. In 32 successfully transplanted patients, restoration of normal or near normal renal function (serum creatinine less than 1.9 mg/100 ml) was not always followed by an immediate improvement in active calcium absorption. Calcium absorption, especially in female patients, was adversely affected by the required immunosuppressive prednisone therapy and improvement was slow.

Absorption↗

Adverse effect of splenectomy in renal transplantation.

Between January 1968 and June 1974 at Newcastle upon Tyne, 63 patients underwent splenectomy in association with transplantation; 45 of these had splenectomy with bilateral nephrectomy before (20) or at the time of (25) transplantation; 18 had post-transplant splenectomy for leucopenia. Mortality was significantly higher in splenectomized patients than in 136 non-splenectomized controls. Of the 63 splenectomized patients, 25 died within 1 year of transplantation, 12 of severe infection associated with leucopenia. Although splenectomy produced a temporary rise in white cell count, leucopenia during the first year of immunosuppressive therapy was not significantly less frequent in splenectomized patients than in controls. There was no significant difference in graft loss between the splenectomy and control groups. It is concluded that splenectomy is contra-indicated in patients who are to undergo renal transplantation and confers no benefit when carried out because of leucopenia developing after renal transplantation.

Azathioprine↗

Serum ferritin concentration: a reliable guide to iron overload in uremic and hemodialyzed patients.

The inter-relationships between serum ferritin, hemoglobin, serum iron and total body iron stores were studied in 20 patients with chronic renal failure treated conservatively and in 20 patients on regular hemodialysis. There was no relationship between serum iron or transferrin and bone marrow iron deposits, but serum ferritin concentration was a good indicator of increased marrow iron stores. All patients with serum ferritin levels above 300 microgram/l had increased iron stores. Serum ferritin assay is a useful non-invasive technique for detecting iron overload in uremic and hemodialyzed patients.

Adolescent↗

Haemodialysis-induced leucopenia and activation of complement: effects of different membranes.

The effects on neutrophil count and complement activity of five different haemodialysis membranes were studied. There was no correlation between the degree of neutropenia and intensity of complement activation. With cuprophan membrane both occurred simultaneously but to unrelated degrees; polyacronitrile induced mild, not significant neutropenia but marked activation of complement; polycarbonate membranes induced severe neutropenia without detectable complement activation. Where complement activation occurred it was via the alternative pathway. Haemodialysis induced neutropenia may have many causes and complement activation is probably not the major responsible factor.

Acrylic Resins↗

Collaborative care of hypertensives, using a shared record.

A shared hospital-GP record for control of hypertension was studied in a sample of 60 patients. Over 80% of patients brought the record to hospital duly completed. Two-thirds of GPs, and the hospital staff, assessed the record as a useful aid in the care of hypertensives. It is still employed enthusiastically, three years after its introduction.

Attitude of Health Personnel↗

Kinetics of hemodialysis: a theoretical study of the removal of solutes in chronic renal failure compared to normal health.

A theoretical comparison of various treatment strategies for the dialysis of patients with chronic renal failure has been made covering a wide mol wt spectrum (60 to 5250 daltons) of metabolites. A two-compartment model has been used with the generation rate in the appropriate pool. The comparison for any given metabolite is made, keeping the same level of predicted intracellular concentration as in traditional Kiil treatments, and it is found that the number of treatment hours per week may be reduced pro rata as the dialyzer clearance is increased. This result is independent of the assumed site of metabolite generation, of the distribution volumes, and of the level of the cell wall permeability. The cyclic fluctuation in intracellular concentration and the mean level of intracellular concentration, in relation to the level in normal health, are both predicted for a given metabolite to be lower if thecell wall permeability is assumed to be on the low side rather than on the high side. The clinical implications of the variations in intracellular and extracellular concentration are discussed, and considerable elevation compared to normal health is predicted for both compartments for large molecules, larger than or equal to 1,000 mol wt, which are generated effectively in the extracellular compartment.

Humans↗

The need and use of a phosphate-enriched dialysate during regular hemodialysis.

A disabling osteomalacic syndrome seen only during regular hemodialysis is described. Its features include skeletal fractures, pain, suppression of pre-existing hyperparathyroidism, and failure to improve with any of the vitamin-D metabolites. Phosphate depletion may be an important etiological factor but this could not explain all cases. A trial with phosphate-enriched dialysate and 1alphaOHD3 resulted in sustained clinical improvement in 54% of the patients and healing of fractures in 33%. Other etiological factors independent of 1,25(OH)2D3 deficiency and phosphate depletion must be considered. Current, indirect evidence suggests that accumulation of water toxins including aluminium may be important.

Adolescent↗