Improvement in duration of erection following phosphodiesterase type 5 inhibitor therapy with vardenafil in men with erectile dysfunction: the ENDURANCE study.

OBJECTIVE: The ENDURANCE study evaluated the efficacy of vardenafil, a phosphodiesterase type 5 (PDE5) inhibitor, in men with erectile dysfunction (ED), by measuring the duration of erection leading to successful intercourse using a stopwatch as the assessment instrument. METHODS: This was a randomised, multicentre, double-blind, placebo-controlled, crossover study consisting of a 4-week treatment-free run-in phase after which patients were randomised to either fixed-dose vardenafil 10 mg or placebo (to be administered 60 min prior to intercourse) and entered the first of the two 4-week double-blind treatment periods, separated by a 1-week washout. The primary efficacy end-point was the stopwatch-assessed duration of erection, which was defined as the time from erection perceived hard enough for penetration until withdrawal from the partner's vagina leading to successful intercourse as measured by Sexual Encounter Profile Question 3 (SEP-3). Secondary efficacy end-points included SEP-2 and SEP-3 success rates, the erectile function domain of the International Index of Erectile Function, global assessment questionnaire, change from baseline in duration of erection and duration of erection not leading to successful intercourse. Safety was assessed by adverse events (AEs), laboratory samples, vital signs and ECGs. RESULTS: Of the 191 men included in the safety population, 40% had moderate ED and 33% had severe ED at baseline. The duration of erection (least squares mean +/- SE) leading to successful intercourse was longer with vardenafil than with placebo (12.81 +/- 1.00 min vs. 5.45 +/- 1.00 min; p < 0.001). The differences recorded for all secondary end-points were statistically significant in favour of vardenafil compared with placebo (p < 0.001), with the exception of duration of erection not leading to successful intercourse. Vardenafil was well tolerated in this study; the majority of AEs being mild-to-moderate in intensity. CONCLUSION: Vardenafil 10-mg therapy provided a statistically superior duration of erection leading to successful intercourse in men with ED compared with placebo.

Randomized comparison of the efficacy and safety of cerivastatin and pravastatin in 1,030 hypercholesterolemic patients. The Cerivastatin Study Group.

OBJECTIVE: To determine the relative efficacy and safety of cerivastatin and pravastatin in patients with type II hypercholesterolemia. PATIENTS AND METHODS: In this prospective, double-blind, parallel-group study, hypercholesterolemic patients were randomized to treatment with cerivastatin, 0.3 mg (n=250) or 0.4 mg (n=258), or pravastatin, 20 mg (n=266) or 40 mg (n=256), for 8 weeks. RESULTS: Cerivastatin, 0.3 mg, was significantly more effective than pravastatin, 20 mg, in reducing low-density lipoprotein (LDL) cholesterol from baseline (-29.6% vs -26.8%; P=.008). Cerivastatin, 0.4 mg, was significantly more effective than pravastatin, 40 mg, in reducing LDL cholesterol (-34.2% vs -30.3%; P<.001). A larger proportion of cerivastatin-treated patients had greater than 40% reductions in LDL cholesterol than those receiving pravastatin (11.1% vs 6.0%). The percentage of patients who achieved the National Cholesterol Education Program (NCEP) target was 71.3% with cerivastatin, 0.3 mg, compared with 67.5% with pravastatin, 20 mg, and 74.0% with cerivastatin, 0.4 mg, compared with 71.1% with pravastatin, 40 mg (no significant difference). Cerivastatin, 0.3 mg, reduced total cholesterol to a greater extent than did pravastatin, 20 mg (P<.03). Both agents reduced triglycerides and increased high-density lipoprotein cholesterol to a similar degree (no significant differences). Cerivastatin and pravastatin were well tolerated. CONCLUSIONS: Cerivastatin, 0.3 mg and 0.4 mg, showed greater efficacy than pravastatin, 20 mg and 40 mg, respectively, in lowering LDL cholesterol. Cerivastatin is safe and effective for patients with hypercholesterolemia who require aggressive LDL cholesterol lowering to achieve NCEP-recommended targets.

Stretch-activated ion channels contribute to membrane depolarization after eccentric contractions.

We tested the hypothesis that eccentric contractions activate mechanosensitive or stretch-activated ion channels (SAC) in skeletal muscles, producing increased cation conductance. Resting membrane potentials and contractile function were measured in rat tibialis anterior muscles after single or multiple exposures to a series of eccentric contractions. Each exposure produced a significant and prolonged (>24 h) membrane depolarization in exercised muscle fibers. The magnitude and duration of the depolarization were related to the number of contractions. Membrane depolarization was due primarily to an increase in Na(+) influx, because the estimated Na(+)-to-K(+) permeability ratio was increased in exercised muscles and resting membrane potentials could be partially repolarized by substituting an impermeant cation for extracellular Na(+) concentration. Neither the Na(+)/H(+) antiport inhibitor amiloride nor the fast Na(+) channel blocker TTX had a significant effect on the depolarization. In contrast, addition of either of two nonselective SAC inhibitors, streptomycin or Gd(3+), produced significant membrane repolarization. The results suggest that muscle fibers experience prolonged depolarization after eccentric contractions due, principally, to the activation of Na(+)-selective SAC.

Prolonged recovery and reduced adaptation in aged rat muscle following eccentric exercise.

We tested the hypothesis that exposure to eccentric (lengthening) contractions results in greater damage and more prolonged recovery in aged rat muscle (32 months) than in adult muscle (6 months), and that the adaptation usually associated with a single exposure to eccentric exercise is reduced in the aged muscle. Experiments were performed using a new rat model for aging studies. Fisher 344/Brown Norway F1 Hybrid. An ankle flexor, the tibialis anterior (TA), was subjected to a series of 24 eccentric contractions in situ and contractile function was assessed 1, 2, 5 and 14 days following. Eccentric exercise produced a similar reduction in maximum specific twitch and tetanic tension in the aged and adult muscles at 1 and 2 days postexercise. Adult muscles recovered by 5 days, while aged TA remained significantly impaired. Aged TA was fully restored by 14 days. Exercise adaptation was tested by subjecting the TA to a second exercise 14 days following the first. Contractile function was determined 2 days following the second exercise. Adult TA maintained its pre-exercise specific force following the second exercise, while aged TA again showed a significant reduction. Thus, a single exposure to eccentric exercise produced complete adaptation in the adult TA, but not in the aged muscles.