Critical analysis of the use of skeletal surveys in patients with chronic renal failure

Skeletal radiology and bone histopathology were compared in 82 patients with renal failure. The performance of radiology in detecting lesions was assessed using interobserver studies which showed disappointing levels of agreement probably reflecting the subjective nature of the radiological signs. Radiology was very insensitive in detecting and grading hyperparathyroidism even when histology and serum biochemistry were floridly abnormal. The most useful radiographs for monitoring subperiosteal erosions and vascular and soft tissue calcification are identified.

Renal replacement therapy in patients aged over 60 years

The availability of dialysis for patients with end-stage renal failure in the United Kingdom has lagged behind that in most of the rest of Europe and USA, although there has been considerable improvement over recent years. Concern about prognosis and quality of life on renal replacement therapy, together with shortage of facilities has meant that some elderly people have been denied treatment. A retrospective study of all patients commencing renal replacement therapy in Newcastle between 1974 and 1985 was performed. The five year survival of patients aged more than 60 years at the start of treatment (n = 122) was 53%, compared with 68% for a cohort of individuals aged less than 60 years (n = 632). A questionnaire sent to the 62 elderly patients surviving at the end of the follow-up period revealed that most were married, independent, active and lived in their own home. They were not lonely, generally enjoyed life and were happy with their mode of renal replacement therapy. These results show that elderly patients make good dialysis candidates and they should not be denied treatment on the basis of age alone. Greater funding of renal services is necessary to accommodate these patients.

Whole body leucine turnover and nutritional status in continuous ambulatory peritoneal dialysis

1. Nutritional status and leucine turnover has been measured in ten patients with chronic renal failure before the onset of continuous ambulatory peritoneal dialysis (CAPD) and after 3 months treatment, and in five normal subjects. 2. Somatic muscle protein reserves, as judged by anthropometry and measurement of total body potassium, showed no significant changes after 3 months treatment and were not significantly different from normal. 3. Visceral protein reserves, as judged by serum albumin and plasma amino acids, showed a significant fall after 3 months CAPD and were also lower than in normal subjects. 4. Protein turnover was lower in uraemic than in normal subjects, but the balance between synthesis and breakdown was significantly higher and was maintained after 3 months on CAPD.

Short-term studies on the use of amino acids as an osmotic agent in continuous ambulatory peritoneal dialysis

1. A 1% amino acid dialysis solution with a high concentration of the branched-chain amino acids has been compared with 1.36% glucose in short-term studies. 2. The 1% amino acid solution was as effective an agent as 1.36% glucose with respect to ultrafiltration and clearance of creatinine, urea and potassium. 3. Levels of branched-chain amino acids rose to the upper end of the normal range within 1 h and remained at this level over the entire period of the study. Total and non-essential amino acids had returned to baseline by the end of the cycle. 4. Blood glucose rose to significantly greater levels during the 1.36% glucose exchange than during the 1% amino acid exchange. There was an increase in serum insulin levels during both cycles; this was significantly greater with the 1% amino acid solution than the 1.36% glucose. 5. There was no evidence of short-term metabolic complications with the 1% amino acid solution.

Hypothalamic-pituitary-adrenocortical suppression and recovery in renal transplant patients returning to maintenance dialysis

Sixty-six per cent of a group of 21 renal transplant recipients with chronic renal failure were shown to have adrenal suppression due to glucocorticoid treatment. Gradual withdrawal of steroids in these patients returning to maintenance dialysis therapy was achieved with few symptoms of hypoadrenalism. Adrenal recovery occurred in 52 per cent of patients after three months and 71 per cent after six months. However, the plasma cortisol response to insulin-induced hypoglycaemia, studied in patients in whom adrenal recovery had been demonstrated, was impaired in 46 per cent of cases. These results indicate that corticosteroids in renal transplant recipients induce profound hypothalamic-pituitary-adrenal suppression which is slow to recover. Such patients returning to maintenance dialysis are at risk of acute adrenocortical insufficiency for several months. Although withdrawal of steroids can be achieved safely, cover during periods of stress should be given until the hypothalamic-pituitary-adrenal axis has been shown to respond normally.

Continuous ambulatory peritoneal dialysis after the honeymoon: review of experience in Newcastle 1979-84

Two hundred and twenty nine consecutive patients (129 men, mean age 45) were reviewed 12 to 65 months after starting treatment with continuous ambulatory peritoneal dialysis (CAPD) from January 1979 to December 1983. They received CAPD for a mean of 19.8 (range 0.5-62) months. Actuarial patient survival was 79% at 24 months and 72% at 36 months. Half of the 46 deaths were related to cardiovascular disease, while eight patients died of abdominal complications, including three patients with peritonitis. Peritonitis occurred at a rate of one episode per 35 patient weeks, and 88% of episodes were cleared by one or more courses of antibiotics. This still left peritonitis as the commonest cause of failure of CAPD, leading to a permanent change of treatment in 44 patients and temporary interruption in a further 25. CAPD remains a reasonable medium term treatment in chronic renal failure. Despite the persisting problem of peritonitis the results are comparable with those achieved by haemodialysis, and CAPD has become the treatment of first choice for end stage renal failure in Newcastle. In younger patients judged unsuitable for transplantation and facing long term dialysis, however, haemodialysis is preferred.

Serum calcium status in health and disease: a comparison of measured and derived parameters

The relationship of serum ionised calcium to total calcium was investigated in three series of experiments, each using different ion-selective electrodes. In the first, total and ionised calcium were measured in healthy and patient groups to compare the predictive value of each estimation. In the second and third studies, measured ionised calcium was compared with ionised calcium calculated using 5 different formulae, and with total calcium, both uncorrected, and adjusted for varying protein content using eight formulae. In 144 of 149 healthy subjects, serum ionised calcium and total calcium were normal. There were discrepancies between serum ionised calcium and total calcium in 135 of 572 patients with conditions associated with abnormal calcium metabolism. Correction of total calcium, or calculation of ionised calcium did not significantly improve this figure. Thus, corrected or derived calcium values will not substitute for ionised calcium determination in patients with abnormal calcium metabolism.

Affinity of the aluminium binding protein

The affinity for aluminium of the binding protein (transferrin) in serum was studied by in vitro ultrafiltration and equilibrium dialysis. It was found that the binding of aluminium to transferrin is very tight and cannot be dissociated by prolonged dialysis or desferrioxamine (DFO). The tight binding of aluminium to transferrin may play a role in the development of microcytic hypochromic anaemia in aluminium intoxicated patients despite the presence of adequate iron.

Complement activation in haemodialysis: a comparison of new and re-used dialysers

The magnitude of leucopenia and complement activation when reusing cellulose based (Cuprophan) and synthetic (polyacrylonitrile AN-69S) haemodialysis membranes as well as their modifications by the priming of the dialysers with fresh frozen plasma and by the introduction of a period of stagnation during haemodialysis were studied using radioimmunoassay (C3a), centrifugal analysis (C3d), immunochemical (C3, Factor B) and functional (CH50 and alternate pathway) assays. Our findings demonstrate that complement activation and leucopenia induced by Cuprophan are linked and are modified when the membrane is reused, or primed with plasma protein. However, chemical exposure during reuse to sodium hypochlorite modifies these observations. Reuse of the AN-69S membrane resulted in no modification of either leucopenia or complement activity, but this membrane consistently demonstrated lower levels of C3a than observed with either first use or reused Cuprophan membranes.

Anterior pituitary dysfunction in patients with chronic renal failure treated by hemodialysis or continuous ambulatory peritoneal dialysis

Cortisol, prolactin, and growth hormone responses to insulin-induced hypoglycemia were measured in 20 patients undergoing continuous ambulatory peritoneal dialysis or intermittent hemodialysis. The plasma cortisol responses were normal; however, the increments in serum prolactin and growth hormone concentrations were impaired in most patients. The growth hormone responses were lower (p less than 0.05) in those patients treated by continuous ambulatory peritoneal dialysis, but there were no other significant differences between the two patient groups. These results show that anterior pituitary dysfunction persists in some patients with chronic renal failure despite maintenance dialysis therapy.

Evaluation of glycerol as an osmotic agent for continuous ambulatory peritoneal dialysis in end-stage renal failure

Six patients established on continuous ambulatory peritoneal dialysis entered a trial of treatment with dialysis fluid containing glycerol instead of glucose as the osmotic agent in an attempt to decrease the energy load. They were observed for a further 6 months after reconversion to glucose-based dialysis. During the 6 month control period fluid balance was achieved mainly with a solution containing 76 mmol of glucose/1. Fluid balance was maintained during the 6 month period of treatment with glycerol only by the increased use of solutions containing a high concentration of glycerol (152 mmol/l and 272 mmol/l). Thus the energy value of the absorbed osmotic agent did not differ at a mean of 1607 kJ (384 kcal)/day using glycerol and 1669 kJ (399 kcal)/day using glucose as the osmotic agent. In five subjects, fasting and peak blood glycerol levels did not change over the 6 months, but one subject, who accumulated glycerol, developed symptoms of hyperosmolality after 2 months and glycerol therapy was discontinued. In a further subject glycerol-based dialysis was terminated at 3 months when increasing angina was reported. Mean fasting plasma triglyceride concentrations were 50% higher during the 6 months on glycerol (3.12 +/- 1.12 mmol/l) than on glucose (2.19 +/- 0.97 mmol/l) (P less than 0.05). There was a small rise in very low density lipoprotein-cholesterol concentrations with glycerol dialysis but total cholesterol levels were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemodialysis-induced activation of complement. Effects of different membranes

The ability of cellulose-based (Cuprophan, saponified cellulose ester) and synthetic (polyacrylonitrile, polycarbonate, polymethylmethacrylate) haemodialysis membranes to activate complement during treatment was compared, using functional, immunochemical, radioimmunoassays, and fast centrifugal analysis assay techniques. Cellulosic and synthetic membranes show a striking similarity in their complement activation when measured by immunochemical assays. Functional haemolytic assays for alternate pathway and CH50 demonstrate no significant differences from predialysis values. C3d levels were also unable to demonstrate differences between the membranes. C3a levels, on the other hand, demonstrated significant differences between cuprophan, polyacrylonitrile, and polymethylmethacrylate but not between Cuprophan and polycarbonate membranes. Since comparable alternate-pathway activity of both cellulosic and synthetic membranes was demonstrated, but their C3a release differed, it is possible that certain surfaces that activate complement also possess the ability to absorb components of the alternate pathway.

Loss of pulsatile luteinising hormone secretion in men with chronic renal failure

In an attempt to determine the nature of hypothalamic and pituitary dysfunction in renal failure the secretory patterns of luteinising hormone were measured in men with end stage renal disease and compared with those in healthy controls and renal transplant recipients of similar age distribution. Mean luteinising hormone and oestradiol concentrations were significantly higher and the number of luteinising hormone secretory pulses was significantly lower in uraemic men compared with controls. Plasma testosterone and oestradiol concentrations were significantly lower in renal transplant recipients than normal men, but there were no significant differences in mean gonadotropin concentrations or the number of pulses of luteinising hormone between the two groups. As pulses of luteinising hormone are thought to reflect episodic gonadotropin releasing hormone from the hypothalamus these data suggest that uraemia interferes with central mechanisms controlling synchronised release of gonadotropin releasing hormone. This defect appears to be reversible after successful transplantation.

Methods for studying the binding of aluminum by serum protein

We describe methods for studying the binding of Al by protein in serum: ultrafiltration, gel filtration, and immuno-affinity chromatography. For ultrafiltration we used an Amicon YM10 cellophane membrane with a nominal cutoff of 10 000 Da to separate ultrafiltrable and non-ultrafiltrable Al. For gel filtration we used Sephacryl S-300, and for immuno-affinity chromatography we used anti-transferrin coupled to CNBr-activated Sepharose to identify the Al-binding protein. For 30 normal subjects 54% of the total Al in serum was non-ultrafiltrable; for 30 patients with chronic renal failure being treated by hemodialysis 67% was non-ultrafiltrable. In both groups transferrin was identified as the major Al-binding protein in the serum. Results of gel-filtration studies should be interpreted with caution: some gel media adsorb "free" Al, which can be subsequently taken up by transferrin or desferrioxamine passing through the column. We find affinity chromatography to be a specific and reliable method, suitable for use in quantitative studies.

Methods for studying the binding of aluminum by serum protein

We describe methods for studying the binding of Al by protein in serum: ultrafiltration, gel filtration, and immuno-affinity chromatography. For ultrafiltration we used an Amicon YM10 cellophane membrane with a nominal cutoff of 10 000 Da to separate ultrafiltrable and non-ultrafiltrable Al. For gel filtration we used Sephacryl S-300, and for immuno-affinity chromatography we used anti-transferrin coupled to CNBr-activated Sepharose to identify the Al-binding protein. For 30 normal subjects 54% of the total Al in serum was non-ultrafiltrable; for 30 patients with chronic renal failure being treated by hemodialysis 67% was non-ultrafiltrable. In both groups transferrin was identified as the major Al-binding protein in the serum. Results of gel-filtration studies should be interpreted with caution: some gel media adsorb "free" Al, which can be subsequently taken up by transferrin or desferrioxamine passing through the column. We find affinity chromatography to be a specific and reliable method, suitable for use in quantitative studies.

Continuous ambulatory peritoneal dialysis and renal transplantation: a five year experience

Continuous ambulatory peritoneal dialysis is a new and increasingly popular method of routine dialysis, but its effect on renal transplantation is uncertain. A non-randomised comparison was made of the outcome of grafting in patients who had been treated before transplantation with continuous ambulatory peritoneal dialysis with that in patients treated with haemodialysis. During the five years, 1979-84, after continuous ambulatory peritoneal dialysis was introduced to Newcastle upon Tyne 220 patients have received transplants after either continuous ambulatory peritoneal dialysis (61 patients) or haemodialysis (159 patients). During follow up no significant differences occurred in survival of patients or grafts between the two treatment groups. One year after transplantation the percentages of survivors who had received continuous ambulatory peritoneal dialysis and haemodialysis were 88% and 91% respectively, and overall graft survival was 66% and 72%, respectively. A multiple regression model was used to allow for differences among patients--for example, duration of dialysis and number of preoperative transfusions--on the survival of grafts. When only first cadaver grafts were considered (in 152 patients) graft survival (non-immunological failures excluded) was not significantly different between the patients treated with continuous ambulatory peritoneal dialysis and haemodialysis. Continuous ambulatory peritoneal dialysis is not a risk factor in renal transplantation, and its continued use in treatment of potential renal graft recipients is recommended.

Twenty-four hour hormonal and metabolic profiles in uraemic patients before and during treatment with continuous ambulatory peritoneal dialysis

Circulating intermediary metabolite and hormone concentrations were measured at intervals over 24 h in five uraemic patients before starting dialysis and after 3 months' treatment with continuous ambulatory peritoneal dialysis (CAPD) and in 13 non-uraemic normal controls. Fasting and postprandial glucose concentrations were significantly raised in uraemic patients undialysed and on CAPD but 24 h mean (+/- SEM) levels fell from 6.63 +/- 0.40 to 6.00 +/- 0.26 mmol/l (P less than 0.02) after 3 months' dialysis despite peritoneal glucose absorption. Insulin levels were raised in uraemic patients but were unchanged by CAPD. Uraemia was associated with raised levels of the gluconeogenic precursors lactate and alanine and a further rise in fasting and 24 h mean alanine concentrations occurred with CAPD. Fasting total ketone body concentrations were raised in undialysed uraemic patients but concentrations were suppressed throughout the 24 h in CAPD subjects. Fasting triglyceride concentrations were increased in uraemic subjects and mean 24 h levels rose by 30% from 1.55 +/- 0.42 mmol/l before dialysis to 2.02 +/- 0.59 mmol/l during CAPD. Non-esterified fatty acid concentrations were low in uraemic patients and remained low during CAPD. Undialysed and dialysed uraemic patients displayed raised plasma glucagon concentrations throughout the 24 h, suppression of the normal nocturnal secretion of growth hormone and raised mean cortisol levels, which were 23% (CAPD) to 57% (undialysed) higher than in normal controls. The endocrine and metabolic abnormalities of uraemia are not fully corrected by CAPD. Many of the additional changes observed during CAPD reflect an adaptation to the constant absorption of peritoneal glucose.

Dual lumen subclavian catheters for haemodialysis

The dual lumen catheter has recently been developed as a subclavian vascular access device for haemodialysis. This paper describes our preliminary experience with two currently available catheters of this design: the Shiley Dual Lumen Catheter, and the Quinton-Mahurkar Dual Lumen Catheter. The performance of both catheters, characterised by high blood flow rate capabilities, low venous resistances and minimal recirculation, is superior to that of other types of subclavian haemodialysis cannula.

Compensatory renal hypertrophy after donor nephrectomy

Renal length was measured radiographically in 65 living kidney donors, aged 27-69 years, who had undergone unilateral nephrectomy during the past 20 years. In 34 of these subjects, pre- and post-operative kidney length, glomerular filtration rate (GFR) and blood pressure were available for analysis. Male donors developed greater compensatory hypertrophy than female donors. The extent of renal enlargement correlated negatively with the age of the subject at the time of nephrectomy and with the current mean arterial blood pressure. However, no correlation was found between the percentage change in renal length and either GFR or time since nephrectomy.

A clinical appraisal and comparison of double pump single needle dialysis systems

Six recently developed double pump tidal flow single needle systems have been assessed clinically and the magnitude of recirculation, efficiency of dialysis determined and compared with the classical system (Bellco BL 760). Results indicate that the problems of designing twin pump systems with instantaneous response, occlusive rollers capable of generating clinically acceptable blood flow rates has been largely overcome and such systems offer a high degree of patient acceptance, flexibility, safety and an efficiency of dialysis comparable with that obtained using two needle access.

Factors influencing normal reference intervals for creatinine, urea, and electrolytes in plasma, as measured with a Beckman Astra 8 Analyzer

In a study of 514 healthy adults, we used a Beckman Astra 8 Analyzer to establish normal reference intervals for plasma creatinine, urea, and electrolytes. For potassium and chloride these were considerably lower and higher, respectively, than previously reported ranges. All of these analytes showed significant sex-related differences; all except chloride showed age-related changes. The relationship of these biochemical indices to fasting, cigarette smoking, alcohol intake, regular exercise, and the contraceptive pill--independent of these age- and sex-related differences--was assessed by multiple linear regression. The effect was significant in each case. Our results underline the importance of regular review of reference values.

Effect of storage on measurement of ionized calcium in serum of uremic patients

We studied, in 70 acidotic and non-acidotic uremic patients, the analytical variance in serum ionized calcium as related to duration and temperature of storage. Storage of serum or whole blood at 4 degrees C for as long as 6 h did not significantly alter the measured concentration of ionized calcium in the serum. Storage at room temperature for 6 h, or longer at 4 degrees C or -20 degrees C, resulted in inaccuracies in 39 to 79% of the samples of serum and in 38 to 92% of the samples of whole blood. These errors were not negated by correcting the values for ionized calcium to a pH of 7.40. Indeed, corrected values for calcium were even more unreliable in acidotic patients. We conclude that samples from uremic patients should be analyzed for ionized calcium within 2 h, or within 6 h if stored at 4 degrees C.

Effect of storage on measurement of ionized calcium in serum of uremic patients

We studied, in 70 acidotic and non-acidotic uremic patients, the analytical variance in serum ionized calcium as related to duration and temperature of storage. Storage of serum or whole blood at 4 degrees C for as long as 6 h did not significantly alter the measured concentration of ionized calcium in the serum. Storage at room temperature for 6 h, or longer at 4 degrees C or -20 degrees C, resulted in inaccuracies in 39 to 79% of the samples of serum and in 38 to 92% of the samples of whole blood. These errors were not negated by correcting the values for ionized calcium to a pH of 7.40. Indeed, corrected values for calcium were even more unreliable in acidotic patients. We conclude that samples from uremic patients should be analyzed for ionized calcium within 2 h, or within 6 h if stored at 4 degrees C.

Factors influencing normal reference intervals for creatinine, urea, and electrolytes in plasma, as measured with a Beckman Astra 8 Analyzer

In a study of 514 healthy adults, we used a Beckman Astra 8 Analyzer to establish normal reference intervals for plasma creatinine, urea, and electrolytes. For potassium and chloride these were considerably lower and higher, respectively, than previously reported ranges. All of these analytes showed significant sex-related differences; all except chloride showed age-related changes. The relationship of these biochemical indices to fasting, cigarette smoking, alcohol intake, regular exercise, and the contraceptive pill--independent of these age- and sex-related differences--was assessed by multiple linear regression. The effect was significant in each case. Our results underline the importance of regular review of reference values.

Renal osteodystrophy and metastatic calcification in long-term continuous ambulatory peritoneal dialysis

The biochemical data and drug histories related to bone disease were extracted from the case records of 47 patients who had been treated by continuous ambulatory peritoneal dialysis (CAPD) for more than two years. These data were reviewed in conjunction with the skeletal surveys done over the same period in all patients, with particular reference to secondary hyperparathyroidism, osteomalacia and non-visceral metastatic calcification. Paired bone biopsies were available in 20 of these patients and the histology was quantitated. In the majority of our patients secondary hyperparathyroidism was controlled or improved on CAPD. Osteomalacia also improved in two of the three patients in whom it was initially present and did not develop in any patient whilst on CAPD. We did, however, note a high incidence of non-visceral metastatic calcification. Small vessel calcification developed in 19.6 per cent of patients, large vessel calcification developed in 23.9 per cent and soft tissue calcification developed in 21.7 per cent of patients. We conclude that CAPD, as a form of treatment for end-stage renal disease, satisfactorily controls the osteodystrophy associated with renal failure in the majority of patients. The significance of the high incidence of non-visceral metastatic calcification remains to be established.

Urographic findings in adults with chronic pyelonephritis

The radiological findings in a cohort of 138 adults with chronic pyelonephritis are presented and the following conclusions made. Scarring is commoner in the right kidney than the left and is found in the upper, middle and lower poles with decreasing frequency from above down. Agreement between observers in the grading of scarring in urograms taken without standardisation or routine tomography, is sufficiently high to justify the continued use of the intravenous urogram as a screening test but is not high enough to detect any progression of scars in the group over a 6.5-year period. Repetition of urograms seldom reveals the development of calculi or other new abnormalities and is not justified as a clinical routine. The combination of extensive bilateral renal scarring and proteinuria is associated with the worst renal function.

Hyperchloraemia: a non-specific finding in chronic renal failure

To determine the prevalence of hyperchloraemia (plasma chloride concentration of 107 mmol/l or above) in chronic renal failure (CRF), we retrospectively analysed the acid-base and electrolyte status of 102 Italian and 53 English patients with impaired renal function. Hyperchloraemia was a frequent finding at all stages of CRF with a prevalence ranging from 30 to 50%. It was common both in tubulointerstitial nephropathies (45%) and chronic glomerulonephritis (39%). Hyperchloraemic patients were more acidotic than the normochloraemic.

Cardiac abnormalities and exercise tolerance in patients receiving renal replacement therapy

The exercise tolerance of the survivors of a consecutive group of 100 patients in a renal dialysis and transplant programme was compared with the prevalence of cardiac abnormalities detected by exercise testing, echocardiography, and radionuclide angiography. Fifty four patients attended for investigation 27 (SD 7) months after starting renal replacement therapy. Forty three of them (80%) were receiving antihypertensive treatment. Their performance on a bicycle ergometer exercise test was compared with that of 62 normal subjects and the patients divided into five groups of decreasing ability. The exercise tolerance of the patients was very poor, only 17 performing within the normal range. Impairment in exercise capacity was not explained by the type or quality of renal replacement therapy. Fourteen patients developed ischaemic electrocardiographic changes on exercise. Left ventricular ejection fraction was assessed by gated blood pool scanning in 37 patients; all nine of the patients with an abnormally low radionuclide ejection fraction also had abnormal exercise tolerance. Satisfactory M mode echocardiograms were obtained from 45 of the patients, and only two were normal. Left ventricular hypertrophy was detected in 25 (56%) of the echocardiograms, and abnormalities indicating impaired left ventricular function were common and widespread. Grouping all the abnormal cardiac features together for the patients in each exercise group showed a striking linear trend of increasing proportion of cardiac abnormalities with worsening exercise tolerance among the five exercise groups (p less than 0.001). The proportion of patients becoming unemployed within one year of starting renal replacement therapy similarly increased, from nil to 60% from the best exercise group to the most incapacitated. Twenty nine of the original cohort of 100 patients subsequently died, cardiovascular disease accounting for 12 (41%) of these deaths. Diminished exercise tolerance in patients receiving renal replacement therapy is strongly associated with cardiac abnormalities and reduced employment prospects.

Factors affecting development of peritonitis in continuous ambulatory peritoneal dialysis

A questionnaire based survey in patients receiving continuous ambulatory peritoneal dialysis showed that there was an increased incidence of upper respiratory tract symptoms (suggestive of viral illness) in the 14 days before the development of peritonitis. No other factors were identified that might distinguish patients who develop peritonitis. The possibility that viral infections predispose to peritonitis by altering host defence mechanisms in patients receiving this form of renal replacement therapy warrants further study.

Short-term studies on the use of glycerol as an osmotic agent in continuous ambulatory peritoneal dialysis (CAPD)

The use of glycerol as an osmotic agent in two different concentrations (92 mmol/l and 272 mmol/l) in peritoneal dialysis fluid was investigated over 3 days in six patients on continuous ambulatory peritoneal dialysis and compared with two concentrations of glucose (76 mmol/l and 215 mmol/l) in the same patients. The calorific value of the absorbed osmotic agent was lower, by 19% with isotonic and 22% with hypertonic solutions, when glycerol was used in place of glucose. However, glycerol provided significantly lower total ultrafiltration than glucose at each concentration, despite a higher initial osmotic pressure of the glycerol-based solutions. Thus, the higher concentration of glycerol required to provide equal ultrafiltration may offset any calorific advantage. Equilibration of creatinine and urea was slower and creatinine clearance lower with glycerol. Solutions containing glycerol were initially less acid (pH 6.5) than those containing glucose (pH 5.1). Blood glycerol levels, which were in the physiological range with glucose as the osmotic agent, reached a peak 80-fold greater at 4.3 +/- 0.8 mmol/l during dialysis with fluid containing glycerol at 272 mmol/l and eightfold higher at 0.42 +/- 0.09 mmol/l with glycerol at 92 mmol/l. There was no evidence of haemolysis or other toxic effect despite these levels. The rise in blood glucose and insulin noted during the use of glucose-based solutions was not found with glycerol. Circulating levels of lactate, pyruvate, alanine, non-esterified fatty acids and the ketone bodies were similar with the two agents. Although these short-term studies have shown no conclusive advantage of glycerol over glucose, long-term effects of glycerol, particularly on circulating lipid levels, will determine its future role as an osmotic agent in continuous ambulatory peritoneal dialysis.

Surgical aspects of continuous ambulatory peritoneal dialysis--3 years experience

Since January 1979, 122 patients (mean age 38.5 years, range 5-72 years) with chronic renal failure have been treated with continuous ambulatory peritoneal dialysis (CAPD). Peritoneal access was achieved by inserting silicone rubber Tenckhoff peritoneal dialysis catheters (Quinton, Seattle, Washington) by an open (76 per cent) or closed technique. Actuarial analysis showed a patient survival of 98 and 94 per cent and a success rate of 88 and 64 per cent at 1 and 2 years, respectively. Currently, 74 patients are using CAPD and 8 have been treated for 30-36 months. Thirty-five patients (29 per cent) required two or more peritoneal catheters and 69 per cent of these patients are still on CAPD. Catheter-related peritonitis was the most frequent complication (233 separate episodes in 94 patients) and necessitated catheter removal in 16 per cent of episodes, although 37 per cent of patients from whom catheters were removed because of peritonitis later resumed CAPD. Extravasation of dialysate from the peritoneal cavity (31 episodes) and catheter obstruction (31 episodes) required surgical replacement of catheters in 8 and 23 cases, respectively. Twenty patients (16 per cent) developed 24 abdominal hernias, only one of which caused failure of CAPD. Infective and mechanical complications of CAPD frequently require surgical intervention but only occasionally result in failure of the technique, and even multiple catheter replacements are compatible with successful long term CAPD.

Bone disease in long-term hemodialysis patients with low dialysate aluminium

The dialysis unit in Sunderland uses softener water treatment with low Al concentration (dialysate mean Al 22 micrograms/L) but employs continuous oral Al (OH)3 to control serum phosphate. Thirty-one patients, 22 males and 9 females, with a mean age of 45 years, maintained on hemodialysis for a mean of 48 months were studied. Patients had higher Al concentrations than normal controls (p less than 0.001) and the postdialysis serum Al levels were also significantly higher than the predialysis levels. Twenty-four of 31 patients had evidence of hyperparathyroidism on radiology but only 4 of 31 had fractures. From a histopathological point of view, the patients were found to have no lesions (4 patients), osteitis fibrosa alone (17 patients), and osteitis fibrosa combined with osteomalacia (5 patients). The effect of 1-alpha(OH)D3 treatment was checked by repeated bone biopsies. One case of the last group showed no improvement of osteitis fibrosa, while osteomalacia progressed to severe. We conclude that both antacids and dialysate contribute to the serum and tissue Al accumulation in Sunderland Renal Unit, where over a period of ten years only one patient developed Al-related osteomalacia.

Prevalence and pathogenesis of impotence in one hundred uremic men

In a study of dialysis patients 79% of men complained of sexual dysfunction and 61% erectile impotence following uremia and the onset of regular dialysis therapy. Plasma testosterone levels were significantly higher in patients treated by continuous ambulatory peritoneal dialysis (p = 0.001) but the incidence of sexual dysfunction was not different from patients treated by hemodialysis. Although follicle-stimulating hormone levels were higher (p = 0.001) and penile blood pressure index levels lower (p less than 0.05) in patients with impotence, sexual function was not improved by exogenous testosterone, and vasculogenic impotence was identified in only 6% of patients. These findings suggest that a major component of uremic impotence is unrelated to primary testicular failure or penile vascular insufficiency.

Carbohydrate and lipid metabolism during continuous ambulatory peritoneal dialysis (CAPD): the effect of a single dialysis cycle

The effect on hormonal status and intermediary metabolism of a single 6 h dialysis cycle at two different concentrations of dialysate glucose was investigated in six patients on continuous ambulatory peritoneal dialysis. The basal blood glucose level was elevated by 0.5 mmol/l, associated with a threefold increase in basal serum insulin compared with seven normal controls. Blood glucose and serum insulin rose further during dialysis, particularly with hypertonic (215 mmol of glucose/l) dialysis fluid and levels remained high for 6 h after the onset. Plasma glucagon concentrations were 2.7-fold increased and did not decrease to normal during dialysis. Concentrations of the gluconeogenic precursors lactate and alanine were consistently raised, and levels of circulating non-esterified fatty acids and ketone bodies were lowered, particularly with hypertonic dialysis fluid. The long-term effects of sustained hyperinsulinaemia, including suppression of lipolysis and ketogenesis, require further investigation.

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.

The associations of HLA and other genetic markers with glomerulonephritis

One hundred and seventy-nine patients with various forms of glomerulonephritis confirmed histologically were tested for HLA A and B antigens: Thirty-four with membranous glomerulonephritis were also typed for DR antigens. One hundred and forty-one of these patients were further tested for blood group, red cell enzyme, and plasma protein systems. The minimal-change and the mesangio-capillary glomerulonephritis showed a significant association with B8 and Bw44 antigens respectively, whereas the membranous nephritis in addition to B8 was also found to be associated with DR3 antigen. Previously described associations with Henoch-Schönlein and Berger's nephritis were not proved. A large group with nonspecific proliferative glomerulonephritis did not show any association with HLA. Among the other single-gene characters studied, a significant association was found with Bf (Factor B or C3 proactivator) and adenosine deaminase, both markers thought to be involved in the immune response. The close association of the markers located on chromosome 6 and glomerulonephritis indicates that there may be an immunological component in the aetiology of the disease. The significance of the various associations found is discussed.

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.

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.

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.

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.

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.

Fatal pulmonary fibrosis occurring during treatment with cyclophosphamide

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