Biomedical subjects
Publications and source records attributed to G V Raman.
A highly sensitive biological assay for tissue kallikrein is described, using human kininogen as substrate; and quantitation, by radioimmunoassay, of generated kinins. Using purified human urinary kallikrein as a reference standard we have correlated the kininogenase activity of kallikrein with amidase activity as measured by cleavage of the synthetic substrate S2266.
We report a case of meningococcal septicaemia complicated by myocarditis, cardiogenic shock and acute renal failure. Following protracted haemodynamic support and haemodialysis, there was complete recovery of cardiac and renal function.
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A 48-year-old woman presented with a three-week history of recurrent, generalised rash, flitting joint pains, frontal headache and shivering attacks. On admission she was pyrexial and exhibited a symmetrical generalised maculopapular rash with a few target lesions. The rash faded within the first 24 hours, but over the following week it recurred at intervals of 48 hours and was accompanied by fever and headache. She was started on a short course of steroids, which did not alter her symptoms or signs. Eight days after admission, the patient underwent a lumbar puncture, despite the absence of definite signs of meningeal irritation. The cerebrospinal fluid (CSF) was turbid and diagnostic of bacterial meningitis. Cultures of blood and CSF taken on the day of admission both grew Neisseria meningitidis. The patient was successfully treated; symptoms were completely resolved.
We report on a patient with ureterosigmoid anastomosis, who presented with recurrent episodes of confusion, agitation and aggressive behaviour, culminating in coma. Investigations revealed profound hyperammonaemia, which responded to treatment with sodium benzoate and sodium phenylacetate. No definite cause was found for the abnormality, apart from possible urinary tract infection. The patient remains well on a protein restricted diet with mildly elevated levels of plasma ammonia.
We have investigated the pharmacokinetics of the immunosuppressive drug cyclosporin in 11 patients receiving regular dialysis therapy. After a single oral dose of cyclosporin, whole blood concentrations were measured at regular intervals for 24 h. Body fat content was estimated in each subject from the measurement of skin-fold thickness and mid-arm circumference. In ten of the 11 patients there was a relatively uniform response in the increase of cyclosporin blood concentration to a peak within the first 6 h. Calculated area under the blood concentration curve did not correlate with total bodyweight, but correlated strongly with body fat content as well as fat-free mass. This study suggests that more predictable blood concentrations of cyclosporin might be achieved if the initial dose were calculated on the basis of fat-free mass rather than total bodyweight.
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We report a case of rabies acquired in Zambia by a 45-year-old woman who presented with a history of an influenza-like illness, abnormal behaviour and signs of myocarditis. A provisional diagnosis of systemic viral infection was made. Within 12 h of admission the patient developed features of rabies that included hydrophobia. She was artificially paralysed and ventilated electively. Empirical antibiotic therapy was given also. Signs of myocarditis and fever disappeared within 48 h. Her clinical condition remained stable but she required heavy sedation. On the ninth day after admission the patient developed features of inappropriate secretion of antidiuretic hormone and gradually became water-logged. Intake of fluid was therefore restricted. Her level of consciousness deteriorated progressively to the point where sedation was no longer required. Brain death was diagnosed 14 days after admission.
We have developed a simple method of sample collection which allows the measurement of cyclosporin (CsA) to be made from blood obtained from a finger stab and collected onto filter paper. CsA concentrations estimated from blood spots and venous samples obtained at the same time showed good correlation. This method has various practical applications: peak and trough blood CsA concentrations (as well as profiles) may be routinely measured from samples collected by patients at home; it may be of particular value in children and other patients with poor venous access.
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A study to determine the incidence of late-onset lactose intolerance was undertaken in 68 normal Chinese children in Singapore using measurements of breath hydrogen concentrations, following a lactose or milk challenge, as indicator of lactose malabsorption. Evidence of lactose malabsorption was detected in 26% of children given a lactose challenge, and in 21% of those given a milk challenge. It is concluded that late-onset lactase insufficiency is common in Chinese children in Singapore.
A patient with a 12 hour history of headache, breathlessness and hypotension developed acute renal failure necessitating haemodialysis for 12 days. During recovery she developed hypertension, tachycardia and facial flushing. Investigations revealed a right adrenal phaeochromocytoma. Whilst postural hypotension is common in phaeochromocytoma, profound shock with acute renal failure is rare. This may have been precipitated by concomitant drug therapy, myocardial necrosis or by necrosis within the tumour.
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A double-blind study of the effect of three beta-adrenoceptor blocking drugs (beta-blockers) on exercise muscle blood flow (MBF) in 14 normotensive volunteers was carried out. MBF was measured by the xenon-133 clearance technique. MBF was not altered by placebo, sotalol or labetalol. Atenolol significantly reduced MBF compared with placebo, sotalol and labetalol. We conclude that sotalol and labetalol may be more useful than conventional beta-blockers for treatment of hypertension or angina in association with peripheral vascular disease.
This pilot study was undertaken to examine the safety and efficacy of enalapril in the treatment of hypertension associated with impaired renal function. Forty-one patients with glomerular filtration rate (GFR) < or = 50 ml/min received enalapril for up 12 weeks. Blood pressure, renal function, biochemistry and haematology were monitored weekly for 4 weeks and then monthly. Blood pressure was effectively reduced within 4 weeks; this reduction was maintained for at least 12 weeks. Renal function remained stable and there was no significant sustained alteration in any biochemical or haematological parameter. Requirement for additional antihypertensive drugs was reduced during enalapril therapy. These data suggest that enalapril may have a useful role in the management of hypertension associated with renal impairment.
The efficacy of oral treatment with cephradine in peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD) was compared with that of intraperitoneal cefuroxime over one year. There were 29 episodes of peritonitis in each group and a primary cure was achieved in 66% of the patients treated with cephradine compared with 55% of the patients treated with cefuroxime, suggesting that oral cephradine is as effective as a treatment with intraperitoneal cefuroxime. Nineteen of the 29 episodes in each treatment group were considered suitable for out-patient management and there was no difference in the success rate of either antibiotic regimen. The results suggest that out-patient treatment with oral cephradine is an efficient way of treating CAPD peritonitis.