No abstract

The use of internal ureteric stenting in dismembered pyeloplasty performed in infants < 12 months old has, in our hands, led to a dramatic reduction in operative morbidity. The routine use of internal ureteric stents at the time of pyeloplasty is justified.

Dimercaptosuccinic acid (DMSA) studies were performed in 113 infants less than 1 year old at risk of renal scarring. Of these patients 86 presented with urinary tract infection and 27 were asymptomatic. A voiding cystourethrogram was performed in all cases and excretory urography (IVP) was done in 99. More abnormalities were detected by DMSA study when compared to scars on IVP. When both studies were abnormal there was an excellent correlation on a site by site basis. Fever or systemic disorder was not a reliable sign to determine whether there was upper tract involvement with infection. The incidence of DMSA abnormalities in infants increased with high grade vesicoureteral reflux and decreased with low grade reflux. There was no significant difference in the incidence of abnormal kidneys between the infected and noninfected groups, suggesting that renal scarring may occur with sterile reflux.

A series of 208 patients was prospectively assessed for reflux nephropathy by intravenous urography (IVU) and 99mTc-dimercaptosuccinate (DMSA) scintigraphy. All patients were studied at least 3 months after their most recent urinary tract infection and micturating cystourethrography (MCU) was performed prior to the scintigraphic studies. DMSA scintigraphy detected significantly more cortical abnormalities than did IVU. There was also a correlation between cortical abnormalities in the DMSA studies and the degree of reflux on MCU. The validity of DMSA as a cortical imaging agent is evaluated and the histological evidence for its efficacy derived from the animal model is reviewed, lending weight to its establishment as the "gold standard" for renal cortical scarring.

generalized approach to the [9] B. J. Min, 'Wumerical methods for absolute stability analysis," Ph.D. dissertation, [SI P. Vidal, Non/iMar Sumpled Duru Sysremr. New York: Gordon and Breach, 1969. [IO] J. A. Cadzow and H. R. Martens Discrere-Time ond Computer Conrrol Sysrem. stability of PWM feedback control systems," 1. FruNwin IRII., Abstract-Postural and gait stability of a planar five-link model of a biped is considered. Equations of motion, in which external torques appear explicitly are derived by d'Alembert's principle. Postural stability is achieved at arbitrary equilibrium points by open and closed loop torques in order to create the equilibrium point and to make the equilibrium point stable. Television recording of angles and angle rates of all five segments of a human in normal walk is taken and used as reference input to the system in order to generate the open and closed loop torques needed for locomotion. It is shown that one equilibrium point and one set of constant feedback gains suffice. It is also demonstrated that this method can be utilized to compute the forces at the joints and the components of the applied torques as functions of the state of the system. Simulations results of the nonlinear system with linear feedback and added disturbances are presented. The two main applications of this work are in the design of powered prostheses for the handicapped and, more importantly, in nondestructive testing to estimate feedback gains utilized by human beings in standing and in walking.