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Biomedical subjects

B L Rayner

Publications and source records attributed to B L Rayner.

At least 19 recordsLinked to original sources
PubMed2006

Association of pre-eclampsia with the R563Q mutation of the beta-subunit of the epithelial sodium channel.

The R563Q mutation of the beta-subunit of the epithelial sodium channel (ENaC) is associated with hypertension in black and mixed ancestry (MA) men and women in South Africa. The frequency of the R563Q mutation in black and MA women with pre-eclampsia (n= 230) and in controls (n= 198) was studied. The R563Q mutation was found in 7.8% of the women with pre-eclampsia and in 2.6% of controls (P= 0.014). This remained significant if the black women were analysed separately (P= 0.031). We have demonstrated that a genetic variant of the ENaC is associated with pre-eclampsia. This has implications for understanding the pathogenesis and treatment of pre-eclampsia.

Adult↗
PubMed2001

Renal function, sodium and water homeostasis in patients with idiopathic extrahepatic portal vein thrombosis compared with normal healthy controls.

OBJECTIVES: To determine whether portal hypertension in the absence of liver disease contributes to changes in renal function and renal sodium and water handling. METHODS: Nine patients with extrahepatic portal vein thrombosis (PVT) with normal liver function and histology were compared with 9 matched healthy control subjects. All underwent standard measurements of glomerular filtration rate and effective renal blood flow using inulin and paraaminohippuric acid (PAH) clearances, respectively. Sodium excretion and renin and aldosterone levels were studied before, during and after an intravenous saline infusion. RESULTS: At baseline there were no differences in inulin clearance, PAH clearance, fractional excretion of sodium and free water excretion. During and after the saline infusion both groups showed a significant increase in sodium excretion with a reduction in water excretion, while the PAH and inulin clearances remained unchanged. Although aldosterone and renin levels both fell after the infusion, aldosterone levels were significantly lower in the PVT group. There were no other significant differences between the PVT and control groups. CONCLUSION: Renal function and sodium and water handling were comparable in healthy controls and patients with PVT. It is unlikely that portal hypertension alone plays a significant role in the impaired ability to excrete sodium and water in patients with liver cirrhosis.

Adult↗
PubMed2001

Screening for primary aldosteronism--normal ranges for aldosterone and renin in three South African population groups.

OBJECTIVE: To establish normal ranges for plasma aldosterone, renin and aldosterone/renin (A/R) ratio in South African normotensives under typical outpatient conditions, and to estimate the prevalence of primary aldosteronism (PA) among hypertensives in primary care settings. DESIGN AND METHODS: One hundred and thirty-six normotensive subjects and 154 sex- and age-matched hypertensives at three primary care clinics had measurements of blood pressure, plasma creatinine, K+, aldosterone, plasma renin activity, and spot urine for urinary Na+/creatinine ratio. Medication was not withdrawn before testing. RESULTS: Mean plasma renin activity in black normotensive subjects (0.95 +/- 1.25 ng/ml/h, mean +/- standard deviation (SD)) was significantly lower than in white (2.09 +/- 1.12 ng/ml/h; P < 0.0001) and coloured (1.81 +/- 1.86 ng/ml/h, P = 0.013) normotensives. Mean plasma aldosterone in black normotensives (306 +/- 147 pmol/l) was also significantly lower than in white (506 +/- 324 pmol/l, P = 0.0002) and coloured (418 +/- 304 pmol/l, P = 0.0148) normotensives. In hypertensives, there were no significant differences in renin or aldosterone levels between the three population groups. Urinary Na+/creatinine ratios, an index of Na+ intake, were not significantly different in the three population groups. None of the normotensives had an A/R ratio > or = 1,000 plus aldosterone > or = 750, while 7.1% of hypertensives exceeded these levels, suggesting that they are appropriate criteria for screening for PA. CONCLUSIONS: A large fraction of black normotensive subjects had low renin and aldosterone levels compared with whites, suggesting a salt-retaining tendency in black subjects. These results have important implications for the interpretation of plasma renin and aldosterone levels in hypertensive patients. In primary care settings, 7.1% of hypertensives had biochemical results indicating the need for investigation of PA.

Aldosterone↗
PubMed2000

The aldosterone/renin ratio as a screening test for primary aldosteronism.

OBJECTIVE: To investigate the utility of random outpatient plasma aldosterone and renin measurements in screening for primary aldosteronism (PA) in hypertensive patients. DESIGN: Clinical records of hypertensive patients who had aldosterone and renin determinations over a 3-year period were analysed retrospectively. The patients were arbitrarily classified into five groups defined according to the aldosterone level and the aldosterone/renin (A/R) ratio: PA (plasma aldosterone > 500, A/R ratio > or = 1,000; essential hypertension (EHT) (aldosterone < 1,000, A/R < 1000); secondary hyperaldosteronism (SHA) (aldosterone > or = 1,000, A/R < 400); low-renin hypertension (LRHT) (aldosterone < 500, A/R > or = 1,000); miscellaneous hyperaldosteronism (MHA) (aldosterone > or = 1,000, A/R 400-1000). SETTING: A hypertension clinic in a large teaching hospital. PATIENTS AND RESULTS: The sample of 216 hypertensives were classified as follows: EHT 51%, LRHT 8%, PA 32%, SHA 7%, and MHA 3%. Mean plasma potassium values were significantly lower (P < 0.0001) in the PA group compared with essential hypertensives, but plasma K+ was of little utility in identifying individual patients with PA, as 71% were normokalaemic. Adrenal computed tomography scans were performed on 38 of 69 patients with PA, and revealed definite unilateral or bilateral adrenal masses in 7 and probable unilateral masses in a further 4. Five patients underwent unilateral adrenalectomy, confirming adrenal adenomas in 4 and nodular hyperplasia in 1. The minimum prevalence of PA due to adrenal adenoma or hyperplasia was 3.3% of all hypertensives and 10.1% of patients with biochemical PA defined by A/R ratio. Patients with biochemical PA had more target organ damage, and in general responded more favourably to regimens with spironolactone than to conventional therapy. CONCLUSIONS: A random outpatient aldosterone and renin measurement identifies a group of hypertensives with biochemical PA in which there is a significant prevalence of adrenal adenomas, increased prevalence of target organ damage and a good response to spironolactone. These results have major implications for the investigation and management of patients with severe or resistant hypertension.

Adult↗
PubMed1998

Community-acquired Staphylococcus aureus bacteraemia in patients who do not abuse intravenous drugs.

Despite advances in antimicrobial therapy and intensive care support, Staphylococcus aureus continues to cause significant morbidity and mortality. We studied community-acquired S. aureus bacteraemia in a population where intravenous drug abuse is extremely uncommon, prospectively reviewing all such patients (n = 113) admitted to Groote Schuur Hospital from February 1986 to January 1991. Overall mortality was 35%. Factors associated with poor outcome were: confusion on presentation, failure to mount a febrile response, acute renal failure, adult respiratory distress syndrome, shock, endocarditis, disseminated intravascular coagulation and platelet count of < 100 x 10(9)/l. Only confusion, acute renal failure and shock were independently associated with death by stepwise regression analysis. Skin infections were the most commonly identified source of bacteraemia (22%), but in 58% of patients the source was not determined. Twenty-six percent of patients were diabetic. Almost all patients (90%) developed one or more complications. In those who survived, therapy was generally prolonged, with a median of 70 days and range of 7-393 days, depending on the associated complications. Community-acquired S. aureus bacteraemia is a serious condition associated with a high complication rate and mortality.

Acute Kidney Injury↗
PubMed1996

A prospective clinical trial comparing the treatment of idiopathic membranous nephropathy and nephrotic syndrome with simvastatin and diet, versus diet alone.

Of 17 patients with idiopathic membranous nephropathy (IMN) and nephrotic syndrome, 9 were allocated to treatment with simvastatin (an HMG CoA-reductase inhibitor) and low cholesterol diet, and 8 to diet alone. At entry, the treatment and control groups did not differ in mean serum creatinines, chromium-labelled EDTA clearances, urinary protein/creatinine ratios, serum albumins, and lipid profiles. The mean follow up period (+/- SEM) in the treated group was 19.3 (+/- 4.4) months compared with 16.6 (+/- 5.9) months in the control group. At the end of the trial the fall in chromium-labelled EDTA clearances was similar (-1.27 versus -1.28 mls/min/months/1.73 m2) in the treatment and control groups respectively. The mean (+/- SEM) total and LDL-cholesterol had gone from 10.5 (+/- 0.94) and 8.02 (+/- 1) mmol/l to 5.2 (+/- 0.49) and 3.47 (+/- 0.44) respectively in the treated patients. Additionally the mean (+/- SEM) albumin and urinary protein/creatinine ratio went from 25.6 (+/- 2.4) gm/l and 0.52 (+/- 0.09) gm/mmol to 45.5 (+/- 2.8) and 0.13 (+/- 0.04) respectively. There was little change in total and LDL-cholesterol; albumin and urinary protein/creatinine ratio in the control group. This study supports the observation that lowering serum cholesterol in the nephrotic syndrome reduces proteinuria and increases serum albumin levels. No difference in the rate of decline in renal function could be demonstrated.

Adult↗
PubMed1994

Continuous ambulatory peritoneal dialysis: an option in the developing world?

OBJECTIVE: To evaluate specified biomedical, socio-economic, and psychosocial criteria as predictors of therapeutic success to optimize patient selection for continuous ambulatory peritoneal dialysis (CAPD) in a developing country. DESIGN: A retrospective cohort study investigating the relationship between episodes of peritonitis and exitsite infection, and predetermined biomedical, socioeconomic, and psychosocial data. SETTING: A CAPD unit in a large tertiary care teaching hospital. PATIENTS: All 132 patients entering the CAPD program between 1987 and 1991. RESULTS: Overall mean survival time on CAPD was 17.3 months. Peritonitis rates were high, especially among blacks. Multivariate analysis demonstrated that increased peritonitis rates were associated with age, black race, diabetes, and strongly so with several psychosocial factors. Because being black was strongly linked to poor socioeconomic conditions, repeat analysis excluding blacks showed the same associations with the above variables, but, additionally, several socioeconomic factors were associated with high peritonitis rates. No significant explanatory variables were shown for exit-site infections. CONCLUSIONS: The association of biomedical, socioeconomic, and psychosocial variables with high peritonitis rates has important implications for the selection of patients for CAPD in this setting.

Adult↗
PubMed1993

Inoculation of peritoneal dialysate fluid into blood culture bottles improves culture rates.

The aim of the study was to determine if direct inoculation of peritoneal fluid into Bactec blood culture bottles would improve the positive bacteriological yield compared with conventional techniques in continuous ambulatory peritoneal dialysis (CAPD) patients with peritonitis. All patients presenting with suspected peritonitis had peritoneal fluid injected directly into aerobic and anaerobic Bactec blood culture bottles as well as into sterile culture tubes. Thirty-seven paired samples were analysed. Twenty conventional cultures (54%) were positive compared with 33 (89%) done according to the Bactec system (P < 0.002). In only 1 case did the former technique prove superior. Direct inoculation of peritoneal fluid into Bactec blood culture bottles is therefore superior to conventional methods and has obvious therapeutic implications.

Ascitic Fluid↗
PubMed1992

Community-acquired bacteremia in the elderly: a prospective study of 121 cases.

OBJECTIVE: To describe community-acquired bacteremia in the elderly and correlate clinical and laboratory findings with outcome. DESIGN: Prospective study of consecutive cases. SETTING: Large community-based teaching hospital. PATIENTS: One hundred and twenty-one elderly patients aged 65 to 89 years, seen between February 1, 1986 and January 31, 1988. MAIN OUTCOME MEASURES: Bacteriological cultures, symptoms and signs, laboratory findings, and mortality. RESULTS: Gram-negative organisms accounted for 65 (54%) cases and Gram-positive organisms for 47 (39%) cases, while nine (7%) cases were polymicrobial. E. coli (39%), Klebsiella sp. (8%), S. pneumoniae (14%), and S. aureus (12%) were the most commonly isolated organisms. The overall mortality was 38%. A poor prognosis was associated with confusion as a presenting symptom (P < 0.0003), hypotension (P < 0.0003), and inappropriate or delayed treatment (P < 0.02). A good prognosis was associated with E. coli as the pathogen (P < 0.0003) and prompt, appropriate antibiotic therapy. CONCLUSION: Community-acquired bacteremia in the elderly has a high mortality rate. Early recognition and prompt, appropriate treatment are critical in reducing the mortality.

Aged↗
PubMed1992

Pentoxifylline does not prevent haemodialysis induced neutropaenia or hypoxaemia.

The aim of the study was to determine if oral pentoxifylline prevented dialysis induced hypoxaemia and neutropaenia. Fifteen stable chronic haemodialysis patients were routinely dialysed using either a cuprophane or cellulose acetate membrane. Bloods for white blood count (WCC) and pO2 were taken at time 0, 20, 80, 140 and 200 min. The procedure was repeated in the same patients 2 h after the ingestion of 400 mg of pentoxifylline. There was a highly significant drop in WCC at time 20 min and pO2 over the dialysis period, which was not prevented by pentoxifylline. Pentoxifylline levels taken at time 0 in 11 patients were in the therapeutic range and it is concluded that pentoxifylline does not prevent dialysis induced neutropaenia or hypoxaemia.

Humans↗
PubMed1992

Hearing thresholds in CAPD patients.

Ultra high frequency (UHF, 10-20 kHz) and conventional audiometric thresholds (0,25-8 kHz) were obtained from 42 stable CAPD patients. Twenty-one (50%) and 11 (25%) of the patients had UHF and conventional hearing loss respectively, when compared to age related control data. This was unrelated to length of chronic renal failure and number of treatments with ototoxic drugs. Sixteen of these patients were monitored audiometrically using UHF during a course of vancomycin therapy for peritonitis. There was no significant change in hearing thresholds. In conclusion there is high incidence of hearing loss in CAPD patients which is unrelated to ototoxic drugs.

Adult↗
PubMed1990

Acute renal failure in community-acquired bacteraemia.

Over a 1-year period, 239 patients with community-acquired bacteraemia in positive blood culture were prospectively evaluated to establish the prevalence and outcome of acute renal failure (ARF). Fifty-eight patients (24%) were identified as having ARF defined by a doubling or more in serum creatinine. The overall mortality in this group was 53% compared with 22% for patients with bacteraemia but without ARF (p less than 0.001). Within the ARF group there were two identifiable subgroups. Thirty patients had resolution of renal failure with treatment of the bacteraemia, and only 6 (20%) of these died. Of the remaining 28 where ARF persisted, 25 (89%) died (p less than 0.000001). Nine patients were dialysed, and only 2 survived. The majority of the remaining 24 patients died of overwhelming bacteraemia before dialysis was indicated. ARF is a common finding in community-acquired bacteraemia, and this has a poor prognosis particularly in those without early resolution of renal failure.

Acute Kidney Injury↗
PubMed1990

Is preliminary binephrectomy necessary in patients with autosomal dominant polycystic kidney disease undergoing renal transplantation?

Patients with end-stage chronic renal failure due to autosomal dominant polycystic kidney disease who underwent renal transplantation with or without preliminary binephrectomy were retrospectively studied to determine the effect of binephrectomy on outcome. Nineteen patients were identified. Thirteen patients had no surgery prior to transplantation and six underwent preliminary binephrectomy. One patient died as a result of the nephrectomy. Twenty-one renal allografts were performed on 18 patients of whom seven have died of sepsis; 10 have functioning grafts and one has returned to dialysis. Patients not undergoing preliminary binephrectomy had a statistically significant (p less than 0.05) increase in mortality and morbidity due to septic complications related to polycystic kidney disease. Indications for bilateral nephrectomy should be reconsidered.

Actuarial Analysis↗
PubMed1988

Community-acquired bacteraemia; a prospective survey of 239 cases.

Over a one-year period 239 patients with community-acquired bacteraemia were studied prospectively to evaluate their clinical profile, course and outcome. Gram-negative organisms accounted for 108 (45 per cent) episodes of bacteraemia, Gram-positive 121 (51 per cent) and polymicrobial 10 (4 per cent). The organisms isolated most commonly were E. coli (28.9 per cent), Klebsiella spp. (7.5 per cent), S. pneumoniae (21.3 per cent), S. aureus (12.1 per cent) and haemolytic streptococci (4.6 per cent). The overall mortality was 29.2 per cent and most deaths were caused by bacteraemia or related complications. This condition therefore still has a high mortality despite modern antimicrobial drugs and intensive care. The most important factor in reducing mortality is early recognition and administration of appropriate antimicrobial drugs.

Adolescent↗