Franklin D. McDonald

Effect of Oral Zinc Therapy on Gonadal Function in Hemodialysis Patients: A Double-Blind Study

Zinc deficiency may account for the persistence of gonadal dysfunction in a majority of uremic men despite adequate dialysis. Twenty stable patients having hemodialysis three times a week completed a double-blind trial using either 50 mg of elemental zinc as zinc acetate (10 patients) or placebo (10 patients), orally. At the end of the 6-month study period, a significant increase in the mean (+/- SE) plasma zinc (75 +/- 2 micrograms/dL to 100 +/- 2 micrograms/dL, p less than 0.001), serum testosterone (2.8 +/- 0.3 ng/dL to 5.2 +/- 0.5 ng/mL, p less than 0.001), and sperm count (30 +/- 3 million/mL to 63 +/- 5 million/mL, p less than 0.001) occurred in the zinc-treated group, but not in those receiving the placebo. The zinc-treated group also had a significant fall in serum luteinizing hormone (92 +2- 10 mIU/mL to 49 +/- 26 mIU/mL, p less than 0.005) and follicle stimulating hormone (45 +/- 9 mIU/mL to 25 +/- 7 mIU/mL, p less than 0.05), not seen in the placebo group. Patients receiving zinc had an improvement in potency, libido, and frequency of intercourse not found in the placebo group. These results suggest that zinc deficiency is a reversible cause of gonadal dysfunction in patients having regular hemodialysis.

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.

Renal parenchymal malakoplakia an unusual cause of renal failure.

MALAKOPLAKIA, described in 1902,1 is an unusual chronic inflammatory disease generally confined to the collecting system of the urinary tract. Renal parenchymal involvement is rare and was bilatera...

Acute drug-associated rhabdomyolysis: an examination of its diverse renal manifestations and complications

Thirty patients with drug associated acute nontraumatic rhabdomyolysis were evaluated. Acute renal failure, oliguric (ORF) in ten and nonoliguric (NORF) in another ten patients, was observed. The remaining ten patients did not develop renal failure (NRF). To identify factors that may have contributed to this clinical diversity, these three groups were compared. Data from 51 patients reported in the literature were also included in the analysis. The patients with ORF were slightly younger than patients with NORF, They had higher incidence of muscle swelling and higher serum potassium. ORF was more severe, lasted longer, and required more dialysis than NORF. The group of patients with renal failure had higher incidence of coma and more patients with very hight muscle enzyme elevation than NRF patients. Hypercalcemia, a unique complication of rhabdomyolysis, was reported in 22 patients. It was not seen in patients without renal failure. There were no differences in age, incidence of coma, muscle swelling, and muscle enzyme between those who did and those who did not develop hypercalcemia. Sixteen patients with nerve entrapment had higher incidence of coma and muscle swelling than the rest of the patients.

Effect of diltiazem, a calcium antagonist, on renin secretion from rat kidney slices

Abstract The purpose of these experiments was to characterize the effects of diltiazem on renin secretion from rat renal cortical slices. Incubation of slices in 60 versus 4 mM K medium almost completely abolished renin secretion. Diltiazem antagonized the inhibitory effect in a concentration-dependent manner but had no effect on secretion of slices incubated in 4 mM K medium. Lowering extracellular Ca enhanced the efficacy of diltiazem. These observations demonstrate that Ca influx through voltage-sensitive Ca channels mediates the inhibitory effect of depolarization and further demonstrate that such channels are not open in the basal state of this preparation. In the presence of a concentration of diltiazem which blocked the inhibitory effects of depolarization, both angiotensin II and antidiuretic hormone (ADH) still inhibited secretion. Therefore, both these peptides inhibit secretion by mechanisms which are independent of the voltage-sensitive Ca channels. These observations confirm and extend previous observations suggesting that Ca plays an inhibitory coupling role in the control of renin secretion.

Zinc Tolerance Test in Uremia: Effect of Ferrous Sulfate and Aluminum Hydroxide

The effects of ferrous sulfate and aluminum hydroxide on the oral zinc tolerance test after administration of 25 mg of elemental zinc as sulfate were studied in six hemodialysis patients and six normal controls. Fasting plasma zinc levels, the 2-hour plasma zinc peak, and the area under the plasma zinc curve were significantly lower in patients compared with values in controls (plasma zinc, 92 +/- 4 compared with 108 +/- 3 micrograms/dL, p less than 0.025; 2-hour plasma zinc peak, 159 +/- 8 compared with 228 +/- 17 micrograms/dL, p less than 0.025; and area under the curve, 193 +/- 41 compared with 316 +/- 39 micrograms h/dL, p less than 0.025). Ferrous sulfate (300 mg orally), when administered along with zinc sulfate, decreased the area under the curve significantly (in patients by 28%, in controls by 40%) in comparison with the results obtained when zinc sulfate was given alone. When 30 mL of aluminum hydroxide was administered orally with zinc sulfate, the area under the curve decreased by 60% in controls and 75% in patients (p less than 0.005). These results confirm the presence of diminished zinc absorption in patients with renal failure and show that ferrous sulfate and aluminum hydroxide, which worsen this defect, also impair zinc absorption in normal subjects.

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.

Hypoxemia during Hemodialysis Using Acetate versus Bicarbonate Dialysate

To evaluate the extent and cause(s) of dialysis-related hypoxemia, we studied 10 patients, 7 days apart using acetate (AC) and bicarbonate dialysate (HCO3). We measured arterial blood gases, WBC, minute ventilation (VE) and inspired and expired gas concentrations and calculated the respiratory quotient (R) and the alveolar-arterial oxygen difference (A-a)DO2 before and during hemodialysis. 8 patients developed hypoxemia. Arterial PO2 (PaO2) dropped similarly at 30 min from 93 +/- 5 to 78 +/- 6 (p less than 0.05) and 89 +/- 4 to 79 +/- 5 mm Hg (p less than 0.05) with AC and HCO3, respectively. R and VE decreased during AC (p less than 0.05). (A-a)DO2 increased at 30 min and correlated with the drop in PaO2 during both AC (r = 0.68, p less than 0.025) and HCO3 (r = 0.76, p less than 0.025). The fall in PaO2 also correlated with the fall in WBC count for both AC and HCO3 (r = 0.63, p less than 0.005). The increase in arterial pH during HCO3 (up to 7.45 +/- 0.01) was significantly greater than that during AC (up to 7.42 +/- 0.01) (p less than 0.025), and coincided with a relative decrease in VE. We conclude that (1) HCO3 does not prevent hypoxemia, and (2) hypoventilation V/Q abnormalities and increase in arterial pH, contribute variably to dialysis related hypoxemia depending on the type of dialysate and the time during dialysis.

Effect of renal transplantation on zinc metabolism and taste acuity in uremia. A prospective study

The effect of successful renal transplantation on zinc metabolism and taste acuity was determined prospectively in 15 adult uremic patients. Before transplantation all patients had subnormal concentrations of zinc in plasma and hair, as well as abnormal taste detection and recognition thresholds for sodium (salty), sucrose (sweet), hydrochloric acid (sour), and urea (bitter). Following renal transplantation, abnormalities of taste acuity and zinc metabolism persisted and were accompanied by increased urinary zinc excretion in all patients. Normalization of zinc concentration in plasma and hair as well as taste acuity did not occur until one year after transplantation and was associated with a concomitant decrease in urinary zinc excretion. The plasma zinc levels and daily urinary zinc excretion were inversely related (r=0.62, P<.001) in all patients with normal allograft function. None of the zinc parameters was significantly related to azathioprine or corticosteroid dosage. The results of this study suggest that zinc deficiency and taste abnormalities of uremia persist up to one year posttransplant and may be related to increased urinary zinc losses. The mechanisms underlying post-transplant hyperzincuria as well as clinical significance of zinc deficiency following transplantation remain to be determined.

Effect of ouabain on renin secretion in anaesthetized dogs.

1. Pentobarbitone anaesthetized dogs were used to study the effects on renin secretion of ureteral occlusion and partial aortic clamping before and after intrarenal arterial administration of ouabain.