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Biomedical subjects

R M Taylor

Publications and source records attributed to R M Taylor.

At least 181 records · Page 10Linked to original sources

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.

Adolescent↗

Renal transplantation in the United Kingdom and Ireland--the centre effect.

A detailed audit was done of eight of the twenty-nine transplant centres serving the UK and Ireland. These 8 centres account for one-third of the total renal transplant operations in these two countries. Information was obtained from each centre by means of a comprehensive questionnaire, a 1 1/2 day visit by the three authors, and an analysis of 50 consecutive first cadaver transplants. The 8 centres were chosen in the knowledge that 4 had high and 4 had low 3-month graft-survival rates. Our audit confirmed a centre effect, with a range in 1-year patient survival of from 82% to 96% and of first cadaver graft survival of from 54% to 82%. The two main factors affecting success rate were the rate of irreversible acute rejection and death with a functioning kidney. Our investigations suggested that the centre variation in acute rejection was influenced by blood transfusion and the variation in mortality by steroid dose and recipient age. Careful and well-organised clinical management cannot be easily quantified but was thought to have an important influence. Widespread adoption of pre-transplant blood transfusion and increasing use of cyclosporin will probably contribute to the further lessening of the centre effect which has already been observed over the past few years.

Aged↗

The influence of surgical operations on components of the human immune system.

Surgical operations have been shown to cause a variety of immunological disturbances in man both in vivo and in vitro. With few exceptions the overall picture is one of a generalized state of immunodepression in the postoperative period. The implications of these observations are that host defences may be compromised by surgical procedures, thus providing a 'fertile soil' for bacterial invasion and tumour cell metastasis at the very time when risks from invading pathogens and viable tumour cells are maximal. We have studied the effects of surgical operations on the immune system in 35 patients with benign disease. Surgical procedures were classified as either minor (n = 15) or major (n = 20). A panel of monoclonal antibodies was used to identify peripheral blood lymphocyte subpopulations and analysis was performed using flow cytometry. Simultaneous estimations of plasma alpha-1 proteinase inhibitor (alpha-1-PI), alpha-2-macroglobulin (alpha-2-M), alpha-2-pregnancy-associated glycoprotein (alpha-2-PAG) and plasma suppressive activity (PSA) on stimulated allogeneic lymphocytes were performed before operation and on postoperative days 1, 3, 7, 17 and 21. Circulating numbers of all lymphocyte subpopulations fell significantly following surgery, except for B lymphocytes which did not change. The magnitude, and duration of the reduction in cell numbers and the subpopulation affected was significantly related to the degree of surgical trauma, and returned to pre-operative values by postoperative day 7. Changes in alpha-1-PI, alpha-2-M, alpha-2-PAG and PSA were also significantly related to the degree of surgical trauma, and these plasma changes persisted longer than the cellular disturbances. Surgical operations induce a reversible depression of cellular immunity which precedes plasma suppressive activity in its return to pre-operative levels. Immunostimulating agents such as interferon and the interleukins deserve evaluation as prophylactic agents pre-operatively.

Blood Proteins↗

The detection of renal allograft rejection by fine-needle intrarenal manometry.

The causes of early renal allograft malfunction include rejection, acute tubular necrosis, cyclosporin nephrotoxicity and vascular complications. Fine-needle intrarenal manometry is a potential method of distinguishing rejection from the other causes of malfunction and has been used by Salaman and Griffin in patients' treated with cyclosporin. The technique involves inserting a fine-needle, which is connected to a specially designed manometer, into the substance of the transplant kidney. One hundred and six measurements of intrarenal pressure have been made in 28 patients immunosuppressed with either azathioprine and prednisolone or cyclosporin. Thirteen rejection episodes were identified and confirmed by biopsy. These were treated by pulse steroid (methylprednisolone) therapy. Seven episodes of cyclosporin toxicity were identified and there were fifteen episodes of acute tubular necrosis. The mean intrarenal pressure in the rejecting group was 52.8 mmHg compared with 22.3, 24.1 and 24.3 mmHg for the normal function, acute tubular necrosis and cyclosporin nephrotoxicity groups, respectively (P less than 0.01; Wilcoxon unpaired test). There were no differences within these groups related to the type of immunosuppression used. There were no clinical complications associated with the procedure. Thus in newly transplanted patients, fine-needle intrarenal manometry accurately identified rejection and distinguished it from normal function, acute tubular necrosis and cyclosporin nephrotoxicity in all the patients regardless of the immunosuppressants used.

Cyclosporins↗

CAPD and renal transplantation.

Continuous ambulatory peritoneal dialysis (CAPD) is believed to improve the immune competence of end-stage renal failure patients and to increase the risk of graft rejection following subsequent renal transplantation. At this centre, 220 consecutive renal transplants have been studied in patients treated by either CAPD or haemodialysis (HD). Patient and graft survival was not significantly different for the two treatment groups over a five year follow-up. When only first cadaver recipients were considered (152 grafts) one-year graft survival (non-immunological failures excluded) was 77 per cent for CAPD and 79 per cent for HD patients (P greater than 0.05). Time on dialysis and number of pre-operative transfusions were significantly greater for the HD patients (P less than 0.05). A group of HD and CAPD patients were identified as being matched for age, sex, HLA, A, B, DR antigen matches, pre-operative transfusions and time-on dialysis. One-year graft survival of the CAPD patients was 82 per cent and for the HD patients 61 per cent. Studies of patient lymphocyte function and plasma suppressive activity in vitro revealed no differences between CAPD and HD treated patients. CAPD is not an immunological risk factor in renal transplantation and its continued use in the preparation of patients for transplantation is recommended.

Adolescent↗

Double-blind treatment of seborrheic dermatitis with 2% ketoconazole cream.

Thirty-seven patients with seborrheic dermatitis were treated topically with a 2% ketoconazole cream or its vehicle control in a double-blind study. The subjects were studied for numbers of Malassezia ovalis (Pityrosporum ovale) cells in their scalp scale; changes in numbers of yeast cells and morphology of M. ovalis were tabulated along with clinical assessment of improvement. The 2% ketoconazole cream, but not the placebo cream, reduced the numbers of viable yeast cells on the scalp. The clinical effect of 2% ketoconazole cream was good (75%-95% improvement) or better in eighteen of twenty subjects; the placebo cream produced good results in only three of seventeen subjects treated. Results of this study are consistent with the view that M. ovalis plays a central role in the pathogenesis of seborrheic dermatitis.

Administration, Topical↗

Immunosuppressive plasma factors in malignant disease.

Naturally occurring substances in plasma capable of suppressing immune responses have been described in health and in benign and malignant diseases. The present study attempted to identify the factors responsible for the immunosuppressive activity of plasma from healthy subjects (n = 5) and patients with benign (10) and malignant (12) diseases. Plasma samples were fractionated by gel filtration and the distribution of specific protein was determined. The suppressive activity of plasma and plasma fractions against autologous and allogenic lymphocytes was measured using a rapid in vitro electrophoretic test. Plasma suppressive activity (PSA) was low in normal subjects and well nourished patients with benign disease and was associated entirely with alpha-2-macroglobulin (a2M). PSA was significantly increased in patients with malignancy and was associated mainly with a2M although immune complexes, IgG and small molecular weight substances were also immunosuppressive. Plasma a2M concentrations were similar in all groups but the suppressive activity associated with a2M differed dramatically. The study demonstrates that PSA can be measured quantitatively and that a2M is an important immunoregulatory protein in cancer patients. On the basis of the results obtained a new hypothesis of tumour-mediated immune suppression is proposed.

Adult↗

Renovascular hypertension: ten years' experience in a regional centre.

In a unit serving a population of three million, 60 hypertensive patients with renovascular disease were identified over a 10-year period. The presence of renovascular disease was usually suggested by intravenous urography (IVU), although this was falsely negative in 21 per cent of cases; isotope renography (IR) was normal in a similar proportion of patients (25 per cent). Eight patients were treated medically and 52 underwent surgical procedures; nephrectomy in 32, autotransplantation in 10, by pass graft in six and percutaneous transluminal angioplasty in four. Twenty-three per cent of patients were cured, 37 per cent improved and 40 per cent unchanged one year after surgery, but the response could not be accurately predicted. Clinical features were of some value in that those patients most likely to benefit from surgery were younger, had less severe hypertension of shorter duration, smoked less, had less severe retinopathy and less cardiomegaly. There was also a trend for those with better renal function and less electrocardiographic evidence of left ventricular hypertrophy to benefit from surgery. The IVU and IR did not predict response to surgery but arteriographic appearances of fibromuscular dysplasia indicated there should be a favourable response. The renal vein renin ratio, basal or stimulated, was of no prognostic value since approximately two-thirds of patients with ratios above or below the threshold value had some benefit from surgery. We conclude that the surgical treatment of renovascular hypertension is worthwhile but the number of patients suitable for surgery is small. Clinical features and the results of simple investigations provided the best guide to surgical outcome in our patients.

Adult↗

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.

Abdomen↗