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Biomedical subjects

D N Kerr

Publications and source records attributed to D N Kerr.

At least 73 records · Page 4Linked to original sources

Sequential changes in serum lipids and their subfractions in patients receiving continuous ambulatory peritoneal dialysis.

Serum cholesterol, triglycerides and their fractions in high density (HDL), low density (LDL) and very low density (VLDL) lipoproteins were measured sequentially in fasting patients on continuous ambulatory peritoneal dialysis (CAPD) who entered a prospective study. Of the 30 who entered, all have been followed to 3 months, 24 to 6 months and decreasing numbers to 18 months. Serum total cholesterol, VLDL cholesterol, total triglycerides and VLDL triglycerides all rose significantly during the first 6 months and VLDL cholesterol has remained elevated to 18 months. Changes in other fractions have been insignificant or inconsistent. 1 patient has developed angina. No associations were found between use of high dextrose fluid, weight gain and hyperlipidemia, probably because of consistent practice between patients. Our results confirm the adverse effect of CAPD on serum lipids and the need for dietary modification but are broadly similar to the changes that have been observed during regular hemodialysis.

Adolescent↗

Accumulation of silicone elastomer in regular dialysis.

A retrospective autopsy study of 78 patients treated by some form of dialysis for chronic renal failure in Newcastle 1964-1981 showed that: 1) Particles resembling silicone elastomer were present in 48 per cent of 61 patients haemodialysed with the use of silicone rubber pump inserts but in none of the 11 treated by haemodialysis with other pump inserts or of the six treated by peritoneal dialysis alone; 2) The prevalence of these particles and their density increased with time on haemodialysis; 3) There was little evidence of a tissue reaction to the particles and no association between their presence and histological evidence of liver disease; 4) There was a higher incidence of clinical and biochemical evidence of liver disease in patients with silicone deposits than in those without. Although there are other possible explanations for this higher incidence of hepatic dysfunction it would be safer to assume that silicone particle spallation is not innocuous.

Humans↗

Continuous ambulatory peritoneal dialysis: three years' experience.

We review the experience of the Renal Unit at Newcastle upon Tyne over the three years 1979-1981, during which 122 patients with chronic renal failure were treated by continuous ambulatory peritoneal dialysis (CAPD). Advantages of the technique included wide acceptability to a cross-section of patients reaching the renal unit, including the elderly and diabetics. Patients who experienced both techniques preferred CAPD to haemodialysis because of the greater freedom and sense of well-being. Patient survival was 94 per cent at two years and rehabilitation was as good as could be expected for the age and primary medical complications of the patients. Control of plasma potassium and phosphate was easier than with haemodialysis. Renal osteodystrophy responded well to a combination of CAPD and alfacalcidol therapy over the two year period for which we have performed serial bone biopsies. Serum aluminium was slightly raised as a result of consumption of phosphate binders and presumed uptake from dialysis fluid but no aluminium related disease has yet been encountered. Anaemia was partly corrected by CAPD with haemoglobin rising to about 10 g/dl on average. CAPD was less costly than home haemodialysis over the first three years and has been adopted as our standard treatment for patients who can expect an early transplant. Disadvantages were persisting problems with peritonitis which still occurred at an incidence of one attack per 39 patient weeks over the last two years, and an actuarial success rate for the technique of only 63 per cent at two years. Twenty patients developed hernias. Weight gain was common and occasionally gross. There was a significant rise in serum cholesterol. The arrival of CAPD has allowed us to increase the intake to our renal failure programme by 50 per cent. However, continued expansion of the technique demands advances in prevention of peritonitis, adequate facilities for admission and particularly an expanding hospital haemodialysis programme to accept the less successful patients from CAPD.

Adolescent↗

Haemodialyser reuse: impact on function and biocompatibility.

The functional performance (clearance of small molecules, ultrafiltration and blood loss) and biocompatibility (haemodialysis leucopenia) has been studied for disposable flat plate and hollow fibre haemodialysers utilizing Cuprophan membranes on their first use, and compared with that obtained when reusing by a manual and automated technique. The results obtained relating to functional performance remain unchanged with the exception of blood loss which shows an increase compared with first use. Biocompatibility is modified on reuse but only if the membrane has not been exposed to a rinsing process using sodium hypochlorite.

Humans↗

Osteomalacia in patients with chronic renal failure before dialysis or transplantation.

The case records of 327 patients who underwent bone biopsy in late or terminal renal failure, before any form of dialysis or transplantation, were examined for clues to the aetiology of renal osteomalacia and its manifestations. Fifty four per cent of the biopsies showed pure osteitis fibrosa, 34 per cent osteomalacia with osteitis fibrosa and 12 per cent showed neither abnormality. Osteomalacia was strongly associated with chronic pyelonephritis and obstructive uropathy as primary renal disease. In two matched groups of 100 each, and within the major primary diseases, it was associated with acidosis, hypocalcaemia and normophosphataemia (as opposed to hyperphosphataemia). There was no association with known length or uraemia and only a weak and inconsistent relationship with severity of uraemia. In the few patients studied, there was no relationship between osteomalacia and serum 25-hydroxycholecalciferol level. In contrast to the state of patients treated by haemodialysis, osteomalacia in this undialysed group was manifested by a higher level of serum alkaline phosphatase than pure osteitis fibrosa, serum iPTH did not differ between the groups, there was no predominance of symptoms in one group, other than proximal myopathy which had a weak association with osteomalacia, and Looser zones were more common than complete fractures. Our study shows that osteomalacia has different manifestations, and probably different causes, before and after the start of haemodialysis. These two stages of renal failure should be clearly distinguished in reports of renal bone disease.

Acidosis↗

[Blood phosphate and calcium metabolism in bicarbonate dialysis of chronic stable hemodialysis patients].

Leucocyte count, blood pH and gases, plasma concentrations of total and ionised calcium, of phosphate and PTH were studied in 11 stable patients on chronic haemodialysis alternatively, the sequence being randomised, during acetate (AHD) and bicarbonate (BHD). Initial leucopenia and its subsequent correction were comparable with both dialysis types whereas pO2 and pCO2 transitory decreased only in AHD so that the mechanism of hypoxemia with AHD does not seem to be related to the pulmonary leucostatis but rather to the reflex hypoventilation secondary to the decrease of pCO2 into the acetate dialysis. As regards the bone metabolism, no difference was observed between HDA and HDB considering the increase of total and ionised calcium, the decrease of plasma phosphate and the absence of decrease of PTH, the initial levels of which being however only slightly elevated. However blood pH was significantly (but slightly) higher before the subsequent dialysis in the case of BHD. This more sustained correction of acidosis would be the only theoretical advantage of BHD for the prevention of bone demineralisation.

Acetates↗

Shunt nephritis: report of two cases and review of the literature.

We report two cases of glomerulonephritis associated with infection of cerebrospinal fluid shunts inserted for the treatment of hydrocephalus and comment an another 70 cases reported in the world literature. Although infection of CSF shunts is common, the development of glomerulonephritis is rare. Non-pathogenic bacteria are the commonest infecting organisms. Antibiotics are generally ineffective in eradicating the infection and the glomerulonephritis, but removal of the shunt is usually, though not always, associated with complete resolution of the renal disease.

Adult↗

Dialysis leucopenia--no correction after prolonged washing of the membrane.

Re-use of hemodialysers diminishes the extent of leucopenia observed during hemodialysis. A possible cause of this change is the prolonged washing of the membrane by an aqueous solution on both sides and by protein contained solutions on the blood side which removes some substance from the membrane which affects leucocytes directly or by activation of complement. A series of studies to test this hypothesis were performed using two hemodialysis membranes -Cuprophan (Enka AG) and Cellulate (Cordis Dow Corporation) and the results obtained demonstrate no elution of any water soluble substance from the dialyser membrane.

Humans↗

The effect of hematocrit on the clearance of small molecules during hemodialysis.

Data collected during the evaluation of a series of hemodialysers were analysed to see the effect of hematocrit on the clearance of urea and creatinine. All evaluations were performed on patients with a range of hematocrits with a mean close to 20%. The urea clearance of those in the upper half of the distribution curve (mean hematocrit 29.4%) was not significantly different from that of patients in the lower half of the distribution curve (mean hematocrit 16.9%) whether the clearance was studied at high or low blood flow rates and with hollow fibre or flat plate disposable hemodialysers. Likewise, there was no correlation between hematocrit and urea clearance by regression analysis. In contrast, the clearance of creatinine was affected by hematocrit being greater at lower hematocrit values. This difference was independent of blood flow rate and dialyser type and was confirmed by regression analysis.

Creatinine↗

Osteomalacia in chronic renal failure before dialysis.

Bone biopsies taken from 327 patients before the start of dialysis have been correlated with clinical and biochemical findings to test various theories about the aetiology of osteomalacia. Two groups of patients, 100 with osteomalacia and 100 with pure osteitis fibrosa, have been compared in detail. Osteomalacia is associated with chronic pyelonephritis or obstruction as primary renal disease, and with acidosis, hypocalcaemia and normophosphataemia (as opposed to hyperphosphataemia). We have found no association between osteomalacia and known duration or severity of uraemia and in a small series of observations we have not confirmed previous reports of a close association between osteomalacia and depressed plasma 25(OH) cholecalciferol values.

Acidosis↗

Peritonitis in continuous ambulatory peritoneal dialysis. Laboratory and clinical studies.

During a three year period, 1979-81, 82 patients were treated by continuous ambulatory peritoneal dialysis (CAPD). The incidence of peritonitis was reduced significantly during the three years from one episode per 20 patient-weeks to one episode every 37 patient-weeks. 83% of the 136 episodes of peritonitis were treated successfully by antibiotic therapy alone. 62% of the total episodes were managed successfully with intraperitoneal cefuroxime. in 13 (16%) patients, CAPD failed because of peritonitis. Hospital admission for peritonitis has been reduced to a mean of 4.3 days per patient per year of CAPD. Fron January to September, 1982, Clostridium-difficile colitis developed in 13 patients. This complication was associated with considerable mortality and morbidity and has prompted a change in antibiotic policy. Patients with peritonitis are now given intraperitoneal netilmicin and intravenous vancomycin. Peritonitis remains the main complication of CAPD, but can be minimised by development of adequate facilities for performing CAPD.

Adolescent↗

A method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry.

A simple but reliable method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry is described. No preparatory procedures are required for water samples, although serum is mixed with a wetting agent (Triton X-100) to allow complete combustion of the samples and to improve analytical precision. Precautions to prevent contamination during sample handling are discussed and instrumental parameters are defined. The method has a sensitivity of 35.5 pg and detection limits of 2.3 micrograms Al/l for serum and 1.3 micrograms Al/l for water. The method was used to determine the aluminium concentration in serum of 46 normal subjects. The mean aluminium content was 7.3 micrograms/l (range 2--15 micrograms/l.

Adolescent↗

Blood gas analysis: effect of air bubbles in syringe and delay in estimation.

Two common sources of error in blood pH and blood gas analysis were studied. The effect of delay in estimation was studied in 10 volunteers and 40 patients. Syringes were stored at 0 degree C, (crushed ice), 4 degrees C (refrigerator) and 22 degrees C (room temperature). The pressure of oxygen (PO2) fell significantly by 20 minutes at 4 degrees C and 22 degrees C but did not change significantly at 0 degree C for up to 30 minutes. Blood pH, pressure of carbon dioxide (PCO2), and base excess did not change significantly for up to 30 minutes at 4 degrees C and 22 degrees C and up to 60 minutes at 0 degrees C. The effect of air bubbles in the syringe was studied by leaving a single bubble or froth in contact with the blood for one to five minutes in 40 patients. Po2 rose significantly after two minutes' contact with froth and two minutes' contact with the air bubble, and PCO2 fell significantly after three minutes' contact with the air bubble. Size of the bubble had little effect on rates of change. Blood pH, bicarbonate, TCO2, and base excess did not change significantly after up to five minutes' contact. For accurate estimation of PO2 and PCO2 it is necessary to avoid frothing, to expel all air bubbles within two minutes, and to inject the sample into the machine within 10 minutes or store the syringe in crushed ice. The requirements for blood pH and base excess measurement are less exacting.

Air↗

Effect of aluminium hydroxide on serum ionised calcium, immunoreactive parathyroid hormone, and aluminium in chronic renal failure.

According to the Bricker-Slatopolsky theory, secretion of parathyroid hormone (PTH) is switched on in chronic renal failure by hypocalcaemia due to phosphate retention. In an attempt to reverse this process 20 patients in preterminal renal failure (plasma creatinine 569 +/- 195 mumol/l) were given aluminium hydroxide, 3.8 g daily. They were studied for four weeks and all measurements were made at the start and weekly, except measurements of serum aluminium concentration, which were made at the start and at the end of the fourth week. Mean serum phosphate fell from 1.89 to 1.47 mmol/l (5.9 to 4.6 mg/100), mean serum calcium rose from 2.07 to 2.24 mmol/l (8.3 to 9.0 mg/100 ml), and serum ionised calcium rose from 1.07 to 1.20 mmol/l (4.3 to 4.8 mg/100 ml), but serum immunoreactive PTH did not fall. Thirteen patients had initial serum immunoreactive PTH concentrations at or near to normal and 11 were taking beta-blockers but even in those with neither explanation, PTH concentrations did not fall. Serum aluminium concentrations rose from 0.4 to 1.02 mumol/l (10.9 to 27.4 microgram/l). Aluminium hydroxide corrects serum phosphate, total calcium, and ionised calcium at the price of a rise in serum aluminium concentration; in this study it did not affect serum immunoreactive PTH. The Bricker-Slatopolsky theory still needs verification in studies of patients with chronic renal failure.

Aluminum↗

Superiority of B locus matching over other HLA matching in renal graft survival.

Graft survival after 348 consecutive first cadaver-donor renal transplants was significantly improved by HLA matching when recipients who had received pretransplant blood transfusions were matched with their kidney donor for two HLA-B locus antigens. No other type of HLA matching significantly improved graft survival in transfused recipients nor did any type of HLA matching in non-transfused recipients. Matching for one HLA-DR antigen had no benefit in transfused recipients. Only two patients received kidneys matched for both DR antigens and only two of those in whom DR matching had been performed had not been transfused. These results indicate that pretransplant blood transfusion and selection of graft recipients predominantly on the basis of HLA-B matching has significantly reduced the renal graft rejection rate in Newcastle upon Tyne over two years. Thus, HLA-B antigen matching should be adopted as the main criterion for kidney sharing between transplant centres.

Adult↗