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Biomedical subjects

F D McDonald

Publications and source records attributed to F D McDonald.

At least 55 records · Page 3Linked to original sources
PubMed1981

Ethylene glycol poisoning: diagnosis based on high osmolal and anion gaps and crystalluria.

We report a case of ethylene glycol poisoning in a 54-year-old man found comatose on the street. No history was available. The diagnosis was based on the findings of a high anion gap metabolic acidosis, a high osmolal gap, and the presence of oxalate and hippurate crystals in the urine. The diagnosis was confirmed later by an ethylene glycol level of 775 mg/dl. This case illustrates how these parameters can be used in the emergency department for rapid diagnosis and management.

Acidosis, Renal Tubular↗
PubMed1981

Renal handling of zinc: effect of cysteine infusion.

Zinc clearance studies in anesthetized dogs were performed during hydropenia, mannitol infusion, and infusion of mannitol plus ZnSO4, ZnCL2, or cysteine. Mannitol expansion caused no significant change in Zn clearance. ZnSO4 infusion increased filtered Zn 13-fold without changing clearance. Zn excretion increased only sixfold, indicating increased net Zn reabsorption. Cysteine infusion increased urinary Zn excretion 86-fold, indicating net tubular Zn secretion, some of which derived from nonplasma sources. Stop-flow studies localized Zn reabsorption to the distal nephron during infusion of mannitol and mannitol plus ZnSO4 or ZnCl2. Net Zn secretion was shown to occur in the proximal tubule during cysteine infusion with reversal of the distal reabsorption pattern seen during ZnSO4 and ZnCl2 infusion. Despite increased urinary Zn excretion during ZnSO4 infusion, calcium excretion was unaltered. During cysteine infusion dissociation of tubular handling of CA2+ and Zn occurred in both the proximal and distal tubule. These experiments demonstrate that the nephron under these experimental conditions is capable of both proximal secretion and distal reabsorption of Zn.

Animals↗
PubMed1980

Improvement of uremic hypogeusia by zinc: a double-blind study.

Diminished taste acuity may account for the persistence of protein and caloric malnutrition observed in a majority of hemodialysis patients inspite of liberalization of the prescribed amount of dietary protein. Twenty-two patients undergoing thrice weekly hemodialysis for more than 6 months were tested for taste acuity and plasma zinc concentration, after which a double-blind study was instituted using a zinc supplement (50 mg of elemental zinc as zinc acetate per day) or a placebo. The threshold of taste detection and recognition for salt (NaCl), sweet (sucrose), and bitter (urea) but not for sour (HCl) improved significantly in all patients on zinc supplementation. None of these parameters improved in those taking placebo. During the study period, the mean plasma zinc level increased from 75 +/- 8 to 97 +/- 10 microgram/dl (P less than 0.001) in patients receiving zinc acetate. There was not significant change in plasma zinc level in the placebo group (75 +/- 15 to 80 +/- 15). The results of this study show that uremic hypogeusia improved in association with zinc supplementation and elevation of plasma zinc concentration.

Clinical Trials as Topic↗
PubMed1980

Glycerol-induced myohemoglobinuric acute renal failure in the pregnant rat.

These studies examined the effects of the volume expansion and the enhanced activity of the renin-angiotensin system during pregnancy on the severity of glycerol-induced myoglobinuric acute renal failure (ARF) in the rat. Renal cortical renin content (RCRC) and plasma renin concentration (PRC) were measured during the first, second, and third weeks of pregnancy. There were no significant changes in RCRC during pregnancy, but PRC was significantly elevated by the third week (22 +/- 2 vs. 12 +/- 2 ng angiotensin I/ml/k, p less than 0.001), despite plasma volume expansion as assessed by changes in the hemotocrit (37.7 +/- 0.5 vs. 46.4 +/- 0.6%, p less than 0.001). Despite the elevated PRC, a significant reduction in the severity of ARF was seen during the third week of pregnancy, as assessed by both blood urea nitrogen and inulin clearance measurements. When a sustained natriuresis was superimposed earlier in pregnancy by saline drinking, significantly more protection against ARF was seen, but with less plasma volume expansion. These results suggest that the mechanism by which saline drinking confers protection may be independent of the degree of volume expansion but may be dependent upon the associated sustained natriuresis.

Acute Kidney Injury↗
PubMed1980

Influenza vaccination in kidney transplant recipients: cellular and humoral immune responses.

Influenza infection in renal transplant recipients may cause either morbidity and mortality or acute allograft rejection; thus, routine annual influenza vaccination should be considered. We have studied the humoral and cellular immune responses to influenza virus antigens before and after trivalent vaccine administration in 13 patients and 16 control subjects. The patients, nine of whom were either on alternate-day or low-dose daily steroid therapy, showed highly significant serum hemagglutination-inhibition antibody responses to each influenza virus strain, There was no significant change in mean lymphocyte stimulation index to any influenza virus strain after vaccination in either group. There was no correlation in the patient group between hemagglutination-inhibition antibody titer or response, or lymphocyte stimulation index or response, and the degree of allograft function or dose or duration of immunosuppressive therapy. The vigorous antibody response and the evidence of cellular immunity support the efficacy of influenza vaccination in these patients.

Adult↗
PubMed1980

Phenytoin, renal function and renin release.

Phenytoin (DPH), a widely used anticonvulsant, has been shown to effect membrane transport in a wide variety of tissues. After injection, DPH is known to accumulate in high concentration in the kidney, however the renal effects of this drug have not been investigated. Therefore, these studies were designed to elucidate the effect of DPH on renal function and renin release. Dogs were anesthetized and had renal venous, aortic, brachial and ureteral catheters placed. During each of three successive experimental clearance periods, either saline, propylene glycol vehicle (V) or V + DPH (0.18 mg/kg/min) was infused via a 23-gauge needle in the left renal artery. In five dogs (Group I), the sequences of infusion was saline, (V) and (V). Five animals (Group II) differed only in that V was infused during all three periods. Seven animals (Group III) underwent sequential infusions of V, V + DPH, and V. Infusion of V alone resulted in a significant increase in systemic blood pressure from 120 to 135 mm Hg (P < .05). Significant increases after V infusion were found in urine volume (0.45 to 0.87 ml/min) (P < .05) and osmolar clearance (1.23 to 1.83 ml/min). Infusion of DPH produced a 22% increase in renal blood flow from 238 to 291 ml/min (P < .05) and a fall in renal vascular resistance from 0.51 to 0.41 mm Hg/ml/min (P < .05). Significant increases were also seen in urine volume from 0.87 to 1.58 ml/min (P < .05), urine sodium excretion (157 to 269 microEq/min) (P < .05) and osmolar clearance (1.54 to 2.62 ml/min) (P < .05). Renal renin secretion rate was unchanged in Group I and II animals but DPH infusion resulted in a 7-fold increase in renin secretion from 21 to 151 ng A-I/hr x min (P < .05). We conclude that intrarenal arterial infusion of DPH results in renal vasodilation, diuresis and natriuresis. Furthermore, this agent also stimulates renin release which may be the result of its effect on membrane transport.

Animals↗
PubMed1979

Renal function in Lophius americanus: effects of angiotensin II.

Arterial blood pressure, urine flow rate, and plasma and urine electrolytes were measured in the aglomerular goosefish (L. americanus) before, during, and after the intravenous infusion of angiotensin II (from 5 to 280 ng/min.kg body wt). Increases in arterial blood pressure were directly related to the logarithm of the angiotensin infusion rate (r = 0.62, P less than 0.005). Angiotensin also increased urine flow from 0.676 +/- 0.065 to 0.755 +/- 0.068 ml/h.kg body wt (P less than 0.005) and Na excretion from 41.0 +/- 5.5 to 54.4 +/- 7.0 mumol/h.kg body wt (P less than 0.001). In 17 of the 19 fish infused with angiotensin the diuretic and natriuretic effects were directly related to the logarithm of the infusion rate (r = 0.44, P less than 0.04 and r = 0.51, P less than 0.02, respectively). There was no relationship between the pressor and the diuretic or natriuretic effects of angiotensin II. These results are consistent with inhibitory effects of angiotensin on solute transport by aglomerular tubules.

Angiotensin II↗
PubMed1979

Zinc metabolism in uremia.

Subnormal plasma zinc levels have been reported in uremic patients. However, detailed studies regarding zinc status in uremia are not available. Twenty-five patients with chronic renal failure (10 undergoing maintenance hemodialysis, five receiving chronic peritoneal dialysis, and 10 nondialyzed azotemic patients) had lower concentration of zinc in plasma, leukocytes, and hair as well as increased plasma ammonia and ribonuclease activity compared to age- and sex-matched controls (p less than 0.001). Similar biochemical changes have been reported in experimentally induced zinc deficiency in both animals and man, except that erythrocyte zinc concentration was elevated in these patients. High erythrocyte zinc concentration may be related to ineffective erythropoiesis in uremia. The results of this study suggest that abnormality in zinc metabolism occurs commonly in patients with chronic renal failure and that it develops prior to initiation of dialysis treatment.

Adult↗
PubMed1979

Phenytoin stimulates renin secretion from rat kidney slices.

Phenytoin stimulated renin secretion from rat renal cortical slices. A sigmoid relationship was found between stimulatory effect and log concentration, from 1 to 8 mg/100 ml. The ED5C was 2.8 mg/100 ml. Basal secretion and the stimulation of secretion elicited by phenytoin were blocked by incubating slices in a K-free medium and by adding 1 mM ouabain to the medium (both of which inhibit Na,K-adenosine triphosphatase activity and increase intracellular Na concentration), and by reductions in the Na concentration of the incubation medium. NaCl in the incubation medium was replaced by choline chloride so that osmolality and Cl concentration were held constant. It is suggested that renin secretion rate is directly related to the transmembrane Na gradient, that phenytoin stimulates secretion by increasing the gradient, and that ouabain, K-free medium and reductions in Na concentration of the medium inhibit secretion by reducing the gradient.

Animals↗