Endourological evaluation and management of leukoplakia of the renal pelvis.

Since August 1989, we have seen 4 patients with leukoplakia of the renal pelvis associated with a longstanding renal stone. In 2 of them, excretory or retrograde pyelography revealed multiple filling defects in the left renal pelvis as well as a renal stone, although urine cytological examination was negative. One of the other 2 patients underwent extracorporeal shock wave lithotripsy (ESWL) for the renal stone, but this was not followed by the passage of stone fragments.

Peripheral factors contributing to the volitional control of firing rates of the human motor units.

Human subjects can volitionally control discharge frequencies of isolated motor units at several frequencies. If the tonic firing rates such as 10 Hz are mainly dependent on the gamma-loop and if Xylocaine blocks gamma-fibers before blocking alpha-fibers, application of Xylocaine would preferentially disturb the tonic rates. After application of Xylocaine to the nerve innervating the motor units the tonic discharges at 10 Hz became irregular, while the phasic discharges at 1 Hz could still be performed volitionally.