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Biomedical subjects

R B Naik

Publications and source records attributed to R B Naik.

At least 19 recordsLinked to original sources

Bicarbonate and bicarbonate/lactate peritoneal dialysis solutions for the treatment of infusion pain.

A randomized, double-blind, cross-over study was undertaken to determine the effects of novel bicarbonate (38 mM) and bicarbonate (25 mM)/lactate (15 mM) containing peritoneal dialysis (PD) solutions on infusion pain in patients who experienced inflow pain with conventional lactate (40 mM) solution. Pain was assessed using a verbal rating scale and the validated McGill Pain Questionnaire (MPQ). Eighteen patients were recruited to the study. Both novel solutions resulted in highly statistically significant reductions in inflow pain compared to the control lactate solution, as assessed with both the verbal rating scale and the MPQ. For all pain variables assessed, the bicarbonate/lactate solution was more effective than the bicarbonate solution in alleviating pain. In conclusion, both solutions reduced the infusion pain experienced with control solution, but the bicarbonate/lactate solution appears to be the most effective. In contrast to the most widespread current treatment, which is the manual injection of sodium bicarbonate, the bicarbonate/lactate solution does not have the associated increased risk of peritonitis.

Bicarbonates↗

Effect of haemodialysis on the control of the circulation in patients with chronic renal failure.

The mechanisms of hypotension during haemodialysis were investigated by studying cardiovascular reflexes, body fluid volumes, and osmolality in 11 patients with renal failure before and after haemodialysis and in 17 normal subjects before and after furosemide diuresis. Blood pressure and heart rate responses to tests of autonomic nervous function were unaffected in either group except that in the patients, head-up tilt after haemodialysis caused a fall in blood pressure. This was associated with a greater fall in cardiac output than before haemodialysis but with a similar rise in peripheral vascular resistance. Resting plasma noradrenaline levels were higher than normal, and the rise in plasma noradrenaline levels in response to tilt was unaffected by haemodialysis. Plasma renin activity rose in response to head-up tilt in normal subjects, but not in patients either before or after haemodialysis. Our studies indicate that changes in plasma potassium and osmolality or the possible peripheral circulatory effects of acetate do not impair the regulation of the circulation in response to haemodialysis. Haemodialysis does not reduce plasma noradrenaline levels. Impaired myocardial function in response to fluid depletion or unresponsiveness of the renin-angiotensin system may contribute to haemodialysis hypotension.

Adult↗

Autonomic neuropathy.

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Autonomic Nervous System Diseases↗

Cardiovascular and autonomic reflexes in haemodialysis patients.

1. Blood pressure and heart rate responses to head-up tilt, standing, the Valsalva manoeuvre, sustained handgrip and cutaneous cold were measured in 27 haemodialysis patients (10 of whom had episodes of haemodialysis-induced hypotension) and 15 control subjects to assess autonomic nervous function. Plasma noradrenaline levels were measured at rest and during head-up tilt. 2. Mean resting supine blood pressure, heart rate and plasma noradrenaline levels were higher in haemodialysis patients than in the control subjects. There was no fall in blood pressure during head-up tilt or standing. The ratio of the R--R intervals of the thirtieth and the fifteenth heart beat after standing (30:15) was lower in the patients; this may be related to their higher resting heart rate. Head-up tilt raised plasma noradrenaline levels in both groups. Heart rate responses to the Valsalva manoeuvre were similar in the patients and control subjects. 3. Systolic blood pressure and heart rate responses to sustained handgrip were similar in both groups. Diastolic and mean blood pressure changes, however, were lower in the patients. The blood pressure and heart rate responses to cutaneous cold were similar in the patients and control subjects. 4. We conclude that generalized autonomic nervous dysfunction does not appear to cause haemodialysis-induced hypotension in patients with chronic renal failure on maintenance haemodialysis.

Adult↗

Renal transplant in a patient with major donor-recipient blood group incompatibility: reversal of acute rejection by the use of modified plasmapheresis.

A 47-year-old patient with blood group O inadvertently received a mismatched kidney from a donor of blood group A. Two days after transplantation, the clinical, biochemical manifestation of an intrarenal, intravascular coagulation was seen. This was treated by plasma exchange with the rapid reversal of all parameters, and reduction of both the IgG and IgM component of the circulating anti-A antibody. The patient, 20 months after transplantation, has normal renal function. Subsequent repeated biopsies have shown no recurrence or manifestation of the effects of the intravascular coagulopathy. This case report documents, for the first time, the reversal of the known deleterious effects of major blood group incompatibility on renal transplantation by the use of a new technique, modified plasmapheresis. Furthermore, it implies that the limitation of transplantation of kidneys on the basis of major ABO blood groups may not be justifiable in all instances.

ABO Blood-Group System↗

Familial gout and renal failure.

Clinical gout and renal failure was seen in a 9-year-old girl. The family tree showed that 9 out of 11 young females in three generations suffered from hyperuricaemia and normal (n = 1), or impaired (n = 8), renal function. One set of twins occurred in each generation and there is only one living male subject. In members with renal failure there was no improvement in renal function after treatment of hyperuricaemia, and in 2 sisters oral contraceptives appeared to precipitate hypertension. This clinical picture may be more common than is generally realised because of failure to compare blood uric acid values with suitable age- and sex-matched controls. The evidence from this family suggests that hyperuricaemia preceded the development of renal failure.

Adult↗

Inappropriate renin secretion and abnormal cardiovascular reflexes in coarctation of the aorta.

The response of the renin-angiotensin system to high and low sodium diets, to standing, and to saralasin infusion was assessed before and after surgical correction of aortic coarctation in a 27-year-old man. The cardiovascular responses to tests of autonomic function were measured. The heart rate responses to the Valsalva manoeuvre and standing were abnormal before operation, and plasma renin levels were high and renin secretion responded poorly to changes in dietary sodium, to standing, and to saralasin. Renin responsiveness and cardiovascular reflexes returned to normal after operation. The results are consistent with the hypothesis that there is a high level of sympathetic efferent activity in coarctation of the aorta and that factors other than increased activity of the renin-angiotensin system may cause high blood pressure.

Adult↗

Effects of vitamin D metabolites and analogues on renal function.

The long-term effects of vitamin D analogues and metabolites on renal function were assessed in 24 patients with and without chronic renal failure. Treatment for periods of 5-45 months did not adversely affect renal function in 10 of 11 patients with stable renal function, although transient hypercalcaemia did cause transient rises in plasma creatinine. Of 13 patients with progressive renal failure before treatment, vitamin D-like compounds or the vehicle used for their administration may have accelerated renal failure in 3 patients independently of changes in plasma calcium or phosphate. Particular difficulties in assessing the effects of vitamin D-like compounds in progressive renal disease are discussed.

Adolescent↗

Serious renal transplant rejection and adrenal hypofunction after gradual withdrawal of prednisolone two years after transplantation.

Ten patients with stable renal function two years after transplantation had their sole immunosuppressive treatment (oral prednisolone 10 mg daily) withdrawn by reducing the daily dose by 1 mg at monthly intervals. Plasma prednisolone concentration, cortisol concentration, creatinine clearance, and serum creatinine concentration were measured in all patients, and the adrenal response to corticotrophin was determined in five by measuring plasma cortisol concentrations before and after tetracosactrin injection. No episodes of rejection occurred in patients taking over 7 mg prednisolone daily. Although three patients apparently required only minimal immunosuppressive treatment (less than 5 mg daily) the remainder suffered episodes of rejection at daily doses below 7 mg. There was a tenuous association between rejection and low plasma cortisol concentration, but neither the pattern of plasma prednisolone concentrations nor the response to tetracosactrin were related to episodes of rejection. Reducing the daily dose of oral prednisolone to under 7 mg should not be attempted in patients with renal transplants unless there are extenuating circumstances.

Adrenal Insufficiency↗

Hypokalaemic hyperchloraemic metabolic acidosis and vesical stone complicating appendicovesical fistulae.

Two patients with appendicovesical fistulae are described. Both presented with gastrointestinal and urinary symptoms. Biochemical examination showed hypokalaemic hyperchloraemic metabolic acidosis; radiographic investigations showed a vesical stone and a communication between the bladder and the bowel. The findings at operation suggested that the fistulae may have arisen as complications of previous appendicitis. The diagnosis of appendicovesical fistulae may be difficult but should be considered in the presence of hypokalaemic hyperchloraemic metabolic acidosis and vesical stones.

Acidosis↗

Ingestion of formic acid-containing agents--report of three fatal cases.

Three patients were treated after they had deliberately ingested domestic agents containing formic acid. The major complications included the local effects on the oropharynx, oesophagus and stomach, metabolic acidosis, derangement of clotting mechanisms with haemorrhage and shock, widespread intravascular haemolysis, disseminated intravascular coagulation and the acute onset of respiratory and renal failure. All 3 patients died between 2 and 14 days after admission. It is the authors' belief that intensive therapy from the outset to include exchange transfusion, infusion of clotting factors, high dose steroids, ventilatory support and peritoneal or haemodialysis with parenteral nutrition may perhaps offer a better chance for survival.

Adult↗