Treatment with the chemotherapeutic combination of 160 mg. trimethoprim plus 800 mg. sulfamethoxazole twice daily increased the serum creatinine level by an average of 2 mg. per 1. in 21 patients. The effect was clearly reversible. The chemical analysis of creatinine was not affected by the addition of trimethoprim, sulfamethoxazole or their metabolites. In 2 subjects given the drug combination for 12 days renal excretion and 24-hour clearances of creatinine decreased but iothalamate 131I clearance was unchanged. Consequently, the rise in serum creatinine does not indicate any decrease in the glomerular filtration rate. The serum creatinine started to rise within 4 hours after oral administration of a single dose. The rise in serum creatinine could be produced with trimethoprim alone but not with sulfamethoxazole alone. When the plasma creatinine was raised to 100 mg. per l. in healthy subjects (by giving creatinine orally), trimethoprim increased the creatinine levels 10 times as much as at normal plasma levels. The effect was interpreted as a competitive inhibition of the mechanism for tubular secretion of creatinine through the base-secreting pathway.

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The effects of glucose and phlorizin on the maximal reabsorptive rates of acetoacetate, sulfate and phosphate were studied in the dog. Increased rates of glucose reabsorption depress maximal acetoacetate, sulfate and phosphate transport. Phlorizin not only reverses this depressant effect of glucose on these three ions, but actually raises their maximal reabsorptive rates above those of the control levels. These findings for acetoacetate and sulfate reabsorption are similar to those previously reported for phosphate reabsorption. The three ions, acetoacetate, sulfate and phosphate share a common reaction with glucose during their tubular transport. Glucose is the predominant compound, depressing any of the other three ions after they have reached maximal reabsorptive rates. The possible implications of these phenomena in the general problem of tubular transport are discussed.

Yellow nail syndrome is characterized by nail changes, respiratory disorders, and lymphedema. In a yellow nail patient with a skeletal titanium implant and with gold in her teeth, we found high levels of titanium in nail clippings. This study aims to examine the possible role of titanium in the genesis of the yellow nail syndrome. Nail clippings from patients with one or more features of the yellow nail syndrome were analyzed by energy dispersive X-ray fluorescence. Titanium was regularly found in finger nails in patients but not in control subjects. Visible nail changes were present in only half of the patients. Sinusitis with postnasal drip and cough was the most common complaint. The dominant source of titanium ions was titanium implants in the teeth or elsewhere. The titanium ions were released through the galvanic action of dental gold or amalgam or through the oxidative action of fluorides. In other patients the titanium was derived from titanium dioxide in drugs and confectionary. Stopping galvanic release of titanium ions or canceling exposure to titanium dioxide led to recovery. In one patient with a titanium implant, the symptoms recurred after renewed exposure to titanium. Yellow nail syndrome is caused by titanium