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Biomedical subjects

E R Yendt

Publications and source records attributed to E R Yendt.

33 records · Page 2Linked to original sources
PubMed1976

The management of the patient with calcium stones.

Results of investigation of 800 patients with renal calculi are presented. The high incidence of medullary sponge kidneys (tubular ectasia) in patients of either sex is stressed as is the low incidence of idiopathic hypercalciuria in the female. Hydrochlorothiazide has been found to be highly effective in preventing recurrence of calcium stones in our personal experience with over 300 patients who have been treated for as long as 14 years with this agent. The efficacy and mode of action of other measures advocated for stone prevention is reviewed.

Calcium↗
PubMed1975

The effects of thiazides on serum and urinary zinc in patients with renal calculi.

Urine zinc (Zn) excretion was significantly higher in 338 male patients with renal calculi than in 21 normal male subjects, but there was no significant difference between 102 female patients with renal calculi and 15 normal female subjects. In 33 patients with renal calculi urinary Zn was less than 50% of the mean normal value; in these patients there is a possibility that lower urine Zn excretion contributes to the formation of renal calculi. Hydrochlorothiazide produced a striking and sustained increase in urinary Zn excretion, which might contribute to the efficacy of this drug in the prevention of calcific renal stones. Serum Zn levels remained normal in the majority of subjects on long term thiazide therapy, but the occasional finding of subnormal levels suggests that long term thiazide therapy carries with it the hazard of Zn deficiency.

Female↗
PubMed1970

The effects of probenecid and thiazides and their combination on the urinary excretion of electrolytes and on acid-base equilibrium.

The effects of commonly used therapeutic doses of hydrochlorothiazide and probenecid, given singly and in combination, on the urinary excretion of monovalent and divalent ions and on acid-base equilibrium were studied in four patients with idiopathic hypercalciuria.Probenecid had no effect on the urinary excretion of monovalent ions but resulted in a sustained increase in the urinary excretion of calcium, magnesium and citrate and a temporary increase in the urinary excretion of ammonium, in addition to its well-known effects on uric acid metabolism. A temporary fall in serum phosphorus levels was also observed.Probenecid also modified the response to hydrochlorothiazide in that the urinary excretion of calcium, magnesium and citrate was greater during combined therapy than when hydrochlorothiazide was administered alone. Probenecid prevented or abolished the increase in serum uric acid levels associated with the use of thiazide but did not modify the effects of hydrochlorothiazide on the urinary excretion of sodium, chloride, potassiu, phosphorus, ammonium, titratable acid and bicarbonate.

Acid-Base Equilibrium↗
PubMed1970

The use of thiazides in the prevention of renal calculi.

The efficacy of hydrochlorothiazide, in a usual dosage of 50 mg. twice daily, in preventing further stone formation was evaluated in 67 patients with recurrent calcium stones. Fifty-three of these patients had idiopathic hypercalciuria (11 with associated urinary infection), one had medullary sponge kidneys and urinary infection, and two had urinary infection only; no cause for stone formation was detected in 11 patients. Urinary infection was also treated when present. Thirty-three patients (Group 1) were stone-free and 34 patients (Group 2) had stones in the urinary tract when treatment was started. In Group 1 during a total of 343 patient years (py) between the onset of stone symptoms and the institution of thiazide therapy there were 194 episodes (.57 per py) including 83 stones passed spontaneously and 30 major operations, but during 72 py on treatment there were only two episodes (.03 per py), both of which resulted in spontaneous passage of stones. The 34 patients in Group 2 had 365 episodes (1.1 per py) during the 343 py before thiazide therapy but only 34 episodes (.53 per py) during the 64 py on treatment. Many episodes in the Group 2 patients were related to previous stones, and in only four of these patients was there clear-cut evidence of new stone formation. Side effects, usually mild, were experienced by 25 patients; in three patients treatment was discontinued because of side effects.

Adult↗
PubMed1970

Renal calculi.

The pathogenesis of renal calculi is reviewed in general terms followed by the results of investigation of 439 patients with renal calculi studied by the author at Toronto General Hospital over a 13-year period. Abnormalities of probable pathogenetic significance were encountered in 76% of patients. Idiopathic hypercalciuria was encountered in 42% of patients, primary hyperparathyroidism in 11%, urinary infection in 8% and miscellaneous disorders in 8%. The incidence of uric acid stones and cystinuria was 5% and 2% respectively. In the remaining 24% of patients in whom no definite abnormalities were encountered the mean urinary magnesium excretion was less than normal. Of 180 patients with idiopathic hypercalciuria, only 24 were females. In the diagnosis of hyperparathyroidism, the importance of detecting minimal degrees of hypercalcemia is stressed; attention is also drawn to the new observation that the upper limit of normal for serum calcium is slightly lower in females than in males. The efficacy of various measures advocated for the prevention of renal calculi is also reviewed. In the author's experience the administration of thiazides has been particularly effective in the prevention of calcium stones. Thiazides cause a sustained reduction in urinary calcium excretion and increase in urinary magnesium excretion. These agents also appear to affect the skeleton by diminishing bone resorption and slowing down bone turnover.

Diet Therapy↗
PubMed1966

Osteomalacia associated with renal bicarbonate loss.

Severe osteomalacia of uncertain etiology was observed in a 44-year-old woman. There was no evidence of chronic renal insufficiency, malabsorption, or of the renal tubular defects classically associated with osteomalacia. However, the dietary history suggested vitamin D deficiency and most of the biochemical findings were compatible with this condition. The unusual feature of the case was a decrease in plasma bicarbonate levels which appeared to be due to a lowered renal tubular threshold for bicarbonate reabsorption. There was no renal tubular defect with respect to hydrogen ion excretion.Rapid symptomatic and radiologic improvement occurred when the dietary intake of vitamin D was increased to approximately 200 I.U. per day and the acidosis was simultaneously corrected with sodium bicarbonate. Although no firm conclusions could be drawn about the relative importance of vitamin D deficiency or chronic acidosis in the production of the osteomalacia, the possibility that the chronic acidosis may have been a major contributing factor is discussed.

Acidosis↗