Uric acid reduces exercise-induced oxidative stress in healthy adults.

Uric acid (UA) possesses free-radical-scavenging properties, and systemic administration is known to increase serum antioxidant capacity. However, it is not known whether this protects against oxidative stress. The effects of raising UA concentration were studied during acute aerobic physical exercise in healthy subjects, as a model of oxidative stress characterized by increased circulating 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) concentrations. Twenty healthy subjects were recruited to a randomized double-blind placebo-controlled crossover study, and underwent systemic administration of 0.5 g of UA in 250 ml of 0.1% lithium carbonate/4% dextrose vehicle or vehicle alone as control. Subjects performed high-intensity aerobic exercise for 20 min to induce oxidative stress. Plasma 8-iso-PGF2alpha concentrations were determined at baseline, after exercise and after recovery for 20 min. A single bout of high-intensity exercise caused a significant increase in plasma 8-iso-PGF2alpha concentrations from 35.0 +/- 4.7 pg/ml to 45.6 +/- 6.7 pg/ml (P<0.01). UA administration raised serum urate concentration from 293 +/- 16 to 487 +/- 16 micromol/l (P<0.001), accompanied by increased serum antioxidant capacity from 1786+/-39 to 1899 +/- 45 micromol/l (P<0.01). UA administration abolished the exercise-induced elevation of plasma 8-iso-PGF2alpha concentrations. High UA concentrations are associated with increased serum antioxidant capacity and reduced oxidative stress during acute physical exercise in healthy subjects. These findings indicate that the antioxidant properties of UA are of biological importance in vivo.

Reasons for patient drop-out from an intracavernous auto-injection programme for erectile dysfunction.

OBJECTIVE: To identify factors that contribute to patient drop-out rates from an intracavernous auto-injection programme for erectile dysfunction. PATIENTS AND METHODS: Forty-seven patients who had been successfully treated with intracavernous vasoactive agents but who subsequently failed to attend follow-up appointments were included in the study. Each patient completed a self-administered questionnaire. RESULTS: Thirty (64%) completed questionnaires were returned. The reasons for withdrawal from treatment are outlined. CONCLUSIONS: The majority of patients who discontinued intracavernous therapy did so for reasons unrelated to treatment associated problems.

Prostaglandin E1 in the medical management of erectile dysfunction in a genito-urinary medicine clinic.

Fifty consecutive patients with erectile failure who had previously proved refractory to papaverine and phentolamine intracavernosal therapy or were inappropriate candidates for such treatment were treated with intracavernosal prostaglandin E1. Forty patients (80%) achieved an erection sufficient for sexual intercourse and after a mean follow-up period of 5.9 months, 32 patients were continuing to use treatment successfully. The average dose was 14 micrograms (range 2.5 to 30 micrograms). There were no cases of priapism or cavernosal fibrosis and no systemic side effects. A low incidence (8%) of local discomfort was reported. We conclude that prostaglandin is a safe and effective vasoactive agent for the treatment of erectile failure in a genito-urinary outpatient clinic.

Intracavernosal papaverine and phentolamine for the medical management of erectile dysfunction in a genitourinary clinic.

A total of 160 men with erectile failure received treatment with 13,030 intracavernosal papaverine and phentolamine injections as outpatients. One-hundred-and-fifteen (72%) achieved an erection sufficient for sexual intercourse and after a mean follow-up period of 14.1 months, 55 (48%) are still attending and successfully using intracavernous therapy. Sixteen patients had a total of 22 episodes of priapism and one patient developed corporeal fibrosis. We conclude that intracavernous papaverine and phentolamine is an effective therapy for erectile failure in a genitourinary clinic.