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Biomedical subjects

R G Luke

Publications and source records attributed to R G Luke.

At least 145 records · Page 8Linked to original sources
PubMed1976

Can mannitol reduce amphotericin B nephrotoxicity? Double-blind study and description of a new vascular lesion in kidneys.

Eleven patients with systemic mycotic infections were treated with amphotericin B, 1 mg/kg, on alternate days. Five patients also received mannitol (M), 1 g/kg, in the amphotericin infusion, while six served as controls (C). Renal function studies prior to therapy were repeated at a total cumulative amphotericin B dosage of 25 mg/kg; renal biopsies were obtained from 10 patients. Inulin and creatinine clearances decreased in both the C and M groups, significantly so in the latter. Urinary concentrating ability of five patients (2C, 3M) decreased as did the capacity of three (1C, 2M) to acidify urine after an acid load. Neither the peak and valley levels of amphotericin B in serum nor the urinary excretion thereof differed between the C and M groups. Striking vacuolization of smooth muscle cells, previously unrecognized, was observed in the media of arterioles and arteries in all renal biopsies. Tubular calcification was present in both groups. In summary, M therapy (1 g/kg) did not protect against the nephrotoxicity of amphotericin B. A unique lesion of the renal vasculature secondary to amphotericin B is described.

Adult↗
PubMed1976

Failure of NaHCO3 and KHCO3 to inhibit renin in the rat.

To evaluate the contribution of chloride to NaCl- and KCl-induced renin inhibition, renin responses to NaCl or NaHCO3 and to KCl or KHCO3 loading were compared in NaCl-deprived rats. Sodium balance in animals drinking isotonic NaHCO3 and NaCl for 9 days did not differ (P greater than 0.40); K+ balance was less positive in NaHCO3-drinking animals (P less than 0.005). Plasma renin activity (PRA) in NaCl-loaded (16.5 ng/ml per h +/- 4.4 SE), but not in NaHCO3-loaded rats (57.2 +/- 9.8), was lower (P less than 0.005) than in NaCl-deprived controls (44.8 +/- 4.7). Renal renin content (RRC) of NaCl but not of NaHCO3-drinking animals was also decreased (P less than 0.02). Both PRA and RRC of KCl- but not of KHCO3-loaded rats (5 meq K+/10 g diet) were lower (P less than 0.01) than in NaCl-deprived controls. After acute intravenous expansion with isotonic NaCl or NaHCO3, increases of plasma volume and plasma K+ did not differ (P greater than 0.05). However, PRA of NaCl-expanded rats (11.8 +/- 3.8) was lower (P less than 0.05) than in NaHCO3-expanded animals (29.7 +/- 8.5). The failure of NaHCO3 and KHCO3 to inhibit renin suggests a role for chloride in mediating the renin responses to Na+ and K+.

Acid-Base Equilibrium↗
PubMed1976

Role of heparin therapy in the outcome of adult hemolytic uremic syndrome.

Intravenous heparin therapy was associated with complete recovery of renal function in a young woman who developed adult hemolytic uremic syndrome while taking oral contraceptive agents. No controlled study is yet available but a review of an additional 36 reported patients who fulfill adequate criteria for the diagnosis of adult hemolytic uremic syndrome suggests that consideration should be given to a trial of heparin therapy in patients with this syndrome in whom renal biopsy shows recoverable glomeruli in the presence of persistent severe impairment of renal function.

Adolescent↗
PubMed1976

Prevalence of hypertension in a renal transplant population on alternate-day steroid therapy.

A study of the prevalence of hypertension in a group of renal transplant patients on alternate-day maintenance steroid therapy was conducted. Twenty-four percent of the transplant clinic population was hypertensive. The factors that were associated with a lower prevalence of hypertension were good graft function, bilateral nephrectomy of the patients' own diseased kidneys (although the majority of our patients without bilateral nephrectomy are normotensive), and use of a living related donor. We conclude that the prevalance of hypertension in transplant patients on alternate-day steroid therapy is low. In the presence of all these favorable factors, only 6% of allograft recipients were hypertensive.

Adolescent↗
PubMed1976

Renal transplant arterial stenosis: amelioration of hypertension and improvement of transplant function after revascularization.

Two of 70 patients treated for a minimum of six months after renal transplantation developed main arterial stenosis to the allograft. Both underwent transplant revascularization and had follow-up at least six months to document lasting benefit. Amelioration of hypertension and improvement of transplant function proved statistically significant. Collateral vessels were not identified on pre-revascularization arteriographic studies. It is suggested that loss of the potential to develop protective collateral channels to transplanted kidneys mandates aggressive evaluation when hypertension and deteriorating renal function occur in the late follow-up period after renal transplantation. In such instances, arteriography and renin determinations may identify salvagable renal allografts, obviating necessity of subsequent retransplantation.

Adult↗
PubMed1975

Effect on cytotoxicity antibodies in potential transplant recipients of leucocyte-poor blood-transfusion.

In a controlled clinical trail, 40 uraemic patients received only leucocyte-poor blood (L.P.B.) while 30 uraemic controls received whole blood and ordinary packed red blood-cells (R.B.C.). Alloimmunisation by HL-A antibodies was found in 15% of the study group and 52% of the control group. Thus, L.P.B. was significantly less likely to produce alloimmunisation than ordinary whole blood or R.B.C. transfusion. Frozen R.B.C may produce even less alloimmunisation, but the advantages of L.P.B. include lower cost, prolonged storage, and ready availability in emergencies.

Adult↗
PubMed1975

Normal serum-lipids in renal-transplant patients.

In contrast to previous reports, most patients (78%) with a successful renal transplant being followed up at the University of Kentucky Medical Center had a normal serum-lipid profile. The patients with hyperlipidaema (22%) had normal fasting insulin levels; they received similar immunosuppressive therapy but were significantly older and more obese than those with normal lipids. This lower prevalence of hyperlipidaemia and the absence of fasting hyperinsulinaemia are tentatively attributed to the use of alternate-day corticosteroid therapy in stable renal-transplant patients. If confirmed, the relative infrequency of hyperlipidaemia in patients of alternate-day corticosteroid therapy would be an additional advantage of that therapy over a daily regimen.

Adolescent↗
PubMed1975

Parenteral essential amino acids in acute renal failure.

Parenteral 1.75 per cent L-essential amino acids in 47 per cent dextrose (Group I 11 patients) or 47 per cent dextrose (Group II, 9 patients) were administered to patients with severe acute renal failure in a single blind-controlled study. Survival rates (55 per cent in Group I and 56 per cent in Group II) and duration of renal failure were similar in the two groups. Rate of daily rise in blood urea nitrogen was significantly reduced during intravenous nutrition in Group I but not in Group II. Serious complications of intravenous nutrition did not occur. Since improved nitrogen metabolism is demonstrated, further trials of essential amino acid therapy in acute renal failure are indicated.

Acute Kidney Injury↗
PubMed1975

Effect of intravenous frusemide on plasma renin concentration: suppression of response in hypertension.

1. Intravenous frusemide produced in normal subjects a prompt rise of plasma renin concentration which correlated with urinary sodium. 2. The renin response to frusemide was suppressed in patients with primary hyperaldosteronism. 3. In patients with low-renin hypertension and normal renin essential hypertension, the renin response to frusemide was similarly suppressed. 4. Suppression of the renin response to frusemide is therefore a feature of hypertension not confined to patients with primary hyperaldosteronism and low-renin hypertension. 5. Thus low-renin hypertension does not appear to constitute a distinct diagnostic entity. 6. It is suggested that suppression of the renin response is part of a long-term renal adaptation to high blood pressure.

Adult↗
PubMed1975

Response of plasma aldosterone to fludrocortisone in primary hyperaldosteronism and other forms of hypertension.

The response of plasma aldosterone to fludrocortisone administration (400 mug 12-hourly for 3 days) was studied in twenty-two patients with primary hyperaldosteronism. No difference was observed in the response between those patients with an adrenal adenoma and those with bilateral adrenocortical hyperplasia, there being no significant change in plasma aldosterone levels across the test period. No separation between the groups was seen when basal plasma renin concentration was related to the aldosterone level following fludrocortisone. It is concluded that the test is of little value in the pre-operative differentiation of these conditions. Twenty-three patients with no demonstrable cause for their hypertension and four with elevated levels of plasma deoxycorticosterone were similarly studied for comparison. These groups demonstrated a normal fall in plasma aldosterone levels following fludrocortisone.

Adenocarcinoma↗
PubMed1975

Minimising the risks of treating acute allograft rejection.

The risks of treating allograft rejection are primarily related to high-dose steroid therapy. To determine when the possible benefit of anti-rejection therapy might not justify the risks, we analysed 20 severe rejection (SAR) episodes for indices of reversibility. Prior renal function was similar in all patients. Ccr fell to 10 ml/min or less, but degree of renal dysfunction was not predictive of reversibility, nor were time since transplant, oliguro/anuria, proteinuria, or hypertension. The only consistent finding was that function began to improve in reversible rejection 3.8 +/- 1 days after beginning therapy. Our rejection treatment, based on this finding, is to use gram doses of IV prednisolone, up to three times in five to seven days. Among 41 patients with 45 grafts so treated, there was no fatality or gastrointestinal haemorrhage. Other complications (fistulae and/or infections) were related to total dose and frequency, to intensive therapy during severe renal dysfunction or to urinary leaks. Limitation of the period of high-dose steroid therapy was associated with reduced morbidity and mortality in renal allograft recipients.

Acute Disease↗
PubMed1974

Effect of adrenalectomy on the renal response to chloride depletion in the rat.

These experiments were aimed at investigating renal behavior towards chloride, as distinct from sodium, during dietary deprivation of these ions in adrenalectomized rats. Adrenalectomized and shamoperated control rats were maintained on saline for 3 wk, then chloride conservation during a very low chloride intake was assessed both with an abundant sodium intake (as buffered sodium phosphate in the drinking water) and after subsequent withdrawal of sodium. When sodium intake was high, there was no difference in chloride conservation between adrenalectomized and control animals, and sodium balance and weight were maintained similarly in both groups. At the same time, both experimental and control rats developed significant hypokalemia and elevation of the plasma bicarbonate levels as compared to other control rats ingesting a normal diet. In another group of adrenalectomized rats sodium phosphate was withdrawn, after normal chloride conservation was observed, and the low-salt diet continued. Negative sodium balance developed and was associated with a negative chloride balance, whereas sham-operated rats continued to conserve sodium and chloride. In further studies during polyuria, both adrenalectomized and control rats developed urinary chloride concentrations of less than 1 meq/liter. Thus adrenalectomized rats can maintain chloride balance on a low chloride, high sodium intake, in contrast to their inability to conserve sodium on a low-sodium intake. It is concluded that renal tubular reabsorption of chloride in adrenalectomized rats is adequate to establish and maintain very low urinary chloride concentrations, which may imply active chloride transport in the papillary collecting duct despite the absence of adrenocortical hormone. In addition, the typical renal response to chloride deprivation, enhanced loss of potassium and accelerated reabsorption of bicarbonate, is not dependent on adrenocortical hormones.

Adrenal Glands↗