A cohort study showing correspondence of low wall shear stress and cephalic arch stenosis in brachiocephalic arteriovenous fistula access.

Background: A brachiocephalic fistula is frequently placed for hemodialysis; unfortunately, cephalic arch stenosis commonly develops, leading to failure. We hypothesized that a contribution to brachiocephalic fistula failure is low wall shear stress resulting in neointimal hyperplasia leading to venous stenosis. The objective of this investigation is to determine correspondence of low wall shear stress and the development of cephalic arch stenosis.

Asymmetric dimethylarginine and whole blood viscosity in renal failure.

Background: Renal failure is a disease with accelerated atherosclerosis beginning with endothelial cell dysfunction. Factors affecting endothelial cell dysfunction include whole blood viscosity (WBV) and asymmetric dimethylarginine (ADMA). The relationship in controls and renal failure was determined.

Association of urinary pH with body weight in nephrolithiasis.

Background: The prevalence of kidney stone disease in the United States is progressively increasing, paralleling the growing rate of obesity. Uric acid nephrolithiasis, a condition associated with a low urinary pH, has been linked to obesity and insulin resistance. Based on these observations, we hypothesized that urinary pH may be inversely associated to body weight in nephrolithiasis.

Outcome of metabolic evaluation and medical treatment for calcium nephrolithiasis in a private urological practice.

Purpose: We determine if medications that have been proven effective for kidney stone prevention in prospective controlled trials can reduce kidney stone recurrence in a private practice of urology better than life-style advice, including hydration.

Materials And Methods: Between July 1, 1995 and December 31, 1996, 203 patients with stones received care from 1 private practice. Physicians chose to evaluate these patients metabolically based on clinical judgement.

Thiazide does not affect urine oxalate excretion.

Purpose: We assessed the effects of thiazide treatment on urine oxalate excretion in patients with kidney stones.

Materials And Methods: Of 537 patients (231 women), 209 (81 women) received thiazide for stone prevention. Urine oxalate was measured in 3, 24-hour urines before treatment, and in 1, 24-hour urine after 6 to 12 weeks of treatment.

Gender differences in seasonal variation of urine stone risk factors.

Purpose: We determined whether men and women differ in urine stone risk factors during the 4 seasons of the year.

Materials And Methods: Measurements from 28,498, 24-hour urines from stone forming patients prior to treatment were analyzed to determine whether monthly variation was significant and whether the sexes differed using ANOVA. Locations of supersaturation maxima were determined.

Influence of urine pH and citrate concentration on the upper limit of metastability for calcium phosphate.

Purpose: We determined the effects on the urine upper limit of metastability for calcium phosphate of citrate concentration and pH, and achievement of the upper limit of metastability by adding calcium or phosphate.

Materials And Methods: The citrate concentration in aliquots of 24-hour urine samples from normal males without a history of kidney stones was increased. The upper limit of metastability was determined by the point of visible crystal formation, as confirmed by increased optical density at 620 nm.

Changes in urine volume accomplished by physicians treating nephrolithiasis.

Purpose: We quantified the changes in urine volume and sodium accomplished in various practice settings and the consequent effects on calcium oxalate supersaturation.

Materials And Methods: We determined comprehensive urine stone risk factors in 2,877 patients treated in 14 practices, including a university referral center and private sector practices. Changes in urine volume and stone risk factors were measured.

Metabolic evaluation of children with urolithiasis: are adult references for supersaturation appropriate?

Purpose: We determined the incidence of urinary stone risk factors in pediatric patients with urolithiasis.

Materials And Methods: Between 1998 and 2001, 71 children with urolithiasis at 2 pediatric institutions underwent metabolic evaluation. The 24-hour urine samples were analyzed outside central laboratory using adult and known pediatric references.