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Biomedical subjects

J R Curtis

Publications and source records attributed to J R Curtis.

At least 127 records · Page 7Linked to original sources

Assessment of renal concentrating ability.

Maximum urine osmolality was measured during a 24-hour control period in normal ambulant and working subjects and hospital inpatients and compared with that achieved after intramuscular injection of 4 microgram desamino-cys-1-8-D-arginine vasopressin (DDAVP). Most of the normal subjects passed maximally concentrated urine at some time during the control period. The results suggest that in less active subjects or hospital inpatients the DDAVP test is a suitable method of assessing renal concentrating ability.

Adult↗

Drug-induced renal disease.

The clinical manifestations of drug-induced renal disease may include all the manifestations attributed to natural or spontaneous renal diseases such as acute renal failure, chronic renal failure, acute nephritic syndrome, renal colic, haematuria, selective tubular defects, obstructive nephropathy, etc. It is therefore vital in any patient with renal disease whatever the clinical manifestations might be, to obtain a meticulous drug and toxin inventory. Withdrawal of the offending drug may result in amelioration or cure of the renal disorder although in the case of severe renal failure it may be necessary to utilise haemodialysis or peritoneal dialysis to tide the patient over the period of acute renal failure. Analgesic nephropathy is an important cause of terminal chronic renal failure and it is therefore vital to make the diagnosis as early as possible. The pathogenesis of some drug-induced renal disorders appears to be immunologically mediated. There are many other pathogenetic mechanisms involved in drug-induced renal disorders and some drugs may under appropriate circumstances be responsible for a variety of different nephrotoxic effects. For example, the sulphonamides have been incriminated in examples of crystalluria, acute interstitial nephritis, acute tubular necrosis, generalised hypersensitivity reactions, polyarteritis nodosa and drug-induced lupus erythematosus.

Acute Disease↗

Serum and plasma concentrations of clindamycin following a single intramuscular injection of clindamycin phosphate in maintenance haemodialysis patients and normal subjects.

Serum levels of clindamycin bioactivity and total clindamycin were studied after single intramuscular injections of 300 mg of clindamycin phosphate in a group of 6 normal subjects and a group of 6 maintenance haemodialysis patients. The patients were studied during a non-dialysis period and then again during haemodialysis. Peak levels tended to be higher and elimination half-lives shorter in the patients than in the normal subjects. Possible reasons for these differences are discussed. There was no evidence that haemodialysis per se influenced the pharmacokinetics of clindamycin phosphate. The proportion of unhydrolysed clindamycin phosphate tended to be higher in the renal failure patients and the reason for this is not apparent. Little, if any, dosage modification is necessary in severe renal fialure although there is probably little point in exceeding a dose of 300 mg intramuscularly every 5 h even in severe infections in patients with severe renal failure. The higher peak levels in patients with advanced renal failure indicate the need for further studies with repeated doses.

Adult↗

Survival in 200 patients treated by haemodialysis and renal transplantation.

The survival rates in 200 patients with terminal renal failure treated by maintenance haemodialysis and renal transplantation were analysed. The overall survival rate (+/- SE) was 81-4 +/- 3% at two years, 68-4 +/- 4% at five years, and 60-8 +/- 4-8% at eight years. Survival was inversely related to age: in those aged 15-34 years overall survival was 89-7 +/- 3-7% at two years, 87-8 +/- 4-1% at five years, and 83-9 +/- 5-5% at eight years. Eighty per cent of the surviving patients were able to work full time. The survival rate in patients returned to dialysis after graft rejection was 87-5% +/- 8-3 at three years.

Adolescent↗

The serum half-life and urine concentrations of cephazolin sodium in patients with terminal renal failure: effect of haemodialysis.

The serum and plasma half-life of cephazolin has been determined in 5 maintenance haemodialysis patients during a non-dialysis period and then again in the same patients during haemodialysis with a Meltec Maxi-Multipont dialyser using cuprophance membranes. The mean half-life during the non-dialysis period was 28.3 hours and fell to a mean of 4.97 hours during haemodialysis. Percentage recovery of cephazolin in the urine was markedly reduced in 4 maintenance dialysis patients although adequate urine concentrations of cephazolin were achieved for many sensitive organisms. A dosage schedule for patients with creatinine clearances of less than 5 ml. per minute and for maintenance haemodialysis patients is suggested.

Adult↗

Possible cobalt toxicity in maintenance hemodialysis patients after treatment with cobaltous chloride: a study of blood and tissue cobalt concentrations in normal subjects and patients with terminal and renal failure.

The myocardial cobalt concentration in a patient who died 3 months after treatment with cobalt was 25-80 times greater than the concentration in control samples. Blood cobalt concentrations in maintenance hemodialysis patients who had been treated 13-20 months previously with cobaltous chloride were significantly higher than those in maintenance hemodialysis patients who had not received cobalt. Prospective studies of blood cobalt concentrations in maintenance hemodialysis patients and normal subjects after the administration of cobaltous chloride were carried out. It was found that prolonged elevation of blood cobalt concentrations occurred in both normals and maintenance hemodialysis patients, but that the blood cobalt concentrations were much higher in the dialysis patients. The urinary excretion of cobalt following the administration of a single dose of cobaltous chloride was studied in two normal subjects. Cobalt metabolism and toxicity are discussed. In view of the limited therapeutic gains to be expected and because of the lack of information regarding the long term significance of elevated blood cobalt concentrations, it is concluded that cobalt should not be used in the treatment of the anemia of patients with sever renal failure.

Aged↗

Use of prazosin in management of hypertension in patients with chronic renal failure and in renal transplant recipients.

Prazosin was used in combination with other antihypertensive drugs in the successful management of hypertension in seven patients with chronic renal failure and six renal transplant recipients, also with chronic renal failure. The addition of small doses of prazosin (mean 3 mg/day) to the antihypertensive regimen produced significant falls in systolic and diastolic blood pressures in both the lying and standing positions. The standing blood pressures were significantly lower than the lying blood pressures during prazosin treatment. Neither the mean blood urea concentrations nor the mean plasma creatinine concentrations changed significantly during prazosin administration. Chromium-51 edetic acid clearances did not change significantly during prazosin treatment in the seven patients in whom it was measured. Severe symptomatic postural hypotension occurred in one patient a week after starting prazosin 3 mg/day. This hypotensive episode was associated with a transient and reversible deterioration in renal function. Another patient developed a rash while on prazosin but it was probably related to propranolol rather than prazosin. Prazosin is thus an effective antihypertensive drug in patients with chronic renal failure, and it may be used with a variety of other drugs. It should be used cautiously, however, since patients with chronic renal failure may respond to small doses, and significant postural falls in blood pressure may result. There was no evidence that the use of prazosin resulted in progressive deterioration in the residual renal function of the patients with chronic renal failure.

Adult↗

Isolated glomerulonephritis with mesangial IgA deposits.

Mesangial deposits of IgA, occurring in the absence of systemic disease known to be associated with nephritis, were detected by immunofluorescence microscopy in renal biopsy specimens from 25 patients (4% of 630 specimens studied). Associated deposits of C3 were always present, usually with IgG, but IgM deposits were less common and C1q was never seen. On light microscopy most of the biopsy specimens showed mesangial of focal nuclear proliferation though some were normal. Fifteen of the 25 patients presented with macroscopic haematuria, which was usually recurrent and preceded by a sore throat, whereas the remaining, and usually older, patients presented with persistent proteinuria and were more likely to have impaired renal function. This incidence of "mesangial IgA disease" is less than that reported by French workers. There was a significantly high incidence of familial renal disease among these patients. No abnormalities of serum complement or IgA concentration were found.

Adolescent↗

The effect of maintenance haemodialysis and renal transplantation on the plasma testosterone levels of male patients in chronic renal failure.

Plasma testosterone levels were measured at the beginning of a 14 h period of haemodialysis, one hour later, midway through the period and at the end, in 18 male patients in chronic renal failure. The level fell from 8.70 +/- 2.63 nmol/l at the start to 8.08 +/- 3.33 nmol/l at the midpoint, and rose again to 10.12 +/- 3.9 nmol/l at the end of a dialysis. All seven of the patients tested on a non-dialysis day showed similar levels at the same time. At the beginning of a 10 h dialysis period 19 other male patients showed a plasma testosterone level of 10.12 +/- 3.99 nmol/l and, at the end, of 8.98 +/- 4.54 nmol/l. Over the same period the plasma corticosteroids rose from 301 +/- 101 nmol/l to 483 +/- 199 nmol/l. Eight male patients who had had successful renal transplantation had plasma testosterone levels of 15.08 +/- 7.49 nmol/l. It is concluded that the plasma testosterone is low in chronic renal failure, but the circadian rhythm is preserved. Treatment with maintenance haemodialysis does not itself affect the plasma testosterone level, or alter the circadian rhythm despite the procedure's being a stress. Successful renal transplantation restores the plasma testosterone to normal in most cases.

Cadaver↗

Tetracycline poisoning in renal failure.

Seven cases are reported in which drugs of the tetracycline group produced a fall in the glomerular filtration rate. In six patients there was a primary underlying renal disease and renal impairment. All seven patients were made seriously ill by the antibiotic. Two patients required immediate haemodialysis; one died and the other continued on dialysis until transplanted. Another patient initially responded to intravenous fluids and protein restriction but his renal function deteriorated and four months later he began maintenance haemodialysis. Three patients required peritoneal dialysis. The seventh patient responded satisfactorily to conservative management. The medical and medicolegal complications arising from the use of tetracycline in patients with renal disease are discussed. Yet another plea is made that drugs of the tetracycline group other than doxycycline should not be given to patients with chronic renal failure.

Adult↗

Pharmacodynamics of practolol in chronic renal failure.

Plasma levels of practolol were measured in advanced chronic renal failure. The plasma half life was found to be markedly prolonged. During haemodialysis considerable shortening of the half life occurred. Therapeutic blood levels of practolol can be achieved in maintenance haemodialysis patients by the administration of 200 mg of the drug by mouth at the beginning and end of each dialysis.

Adult↗