Biomedical subjects

P Perles

Publications and source records attributed to P Perles.

5 recordsLinked to original sources

PubMed1999

Clopidogrel bioavailability: absence of influence of food or antacids.

Two open, randomized, crossover bioavailability studies were carried out to assess the influence of concurrent antacid medication and food on the bioavailability of clopidogrel. A fed/fasting study was conducted in 12 elderly male subjects. Each subject took a single 75 mg dose of clopidogrel on two occasions-in the morning after an overnight fast, either during a standardized breakfast, or with breakfast delayed by 4 hours after dosing. A washout period of 7 days was observed between the two dosings. Twelve healthy male subjects participated in the antacid study. They fasted overnight and for 4 hours after dosing and took a single 75 mg dose of clopidogrel at 8:00 a.m. on two occasions separated by a washout period of 14 days. For one dose, Maalox 2 x 400 mg tablets were taken 1 hour before the clopidogrel dose. Pharmacokinetic parameters of SR26334, the main circulating metabolite of clopidogrel, were derived from plasma concentrations of the latter compound determined before and at regular intervals over 36 hours after dosing. For the fed/fasting study, mean Cmax values (+/-SD) were 2.7+/-0.62 mg/L and 2.1+/-0.96 mg/L for the fasting state and the fed state, respectively and the 90% CI of Cmax ratio was [0.57 - 0.97]. Mean AUC(0-obs) values (AUC to the last observed value) were 7.1+/-1.6 mg.h/L and 7.4+/-1.64 mg.h/L, respectively, and the 90% Cl of AUC ratios were [0.90 - 1.02] and [0.89 - 0.97], respectively. For the antacid study, mean Cmax values were 2.6+/-0.84 mg/L and 2.5+/-0.87 mg/L for the no-antacid regimen and the antacid regimen, respectively, and the 90% CI of Cmax ratio was [0.74 - 1.16]. Mean AUC(0-obs) values were 6.3+/-1.34 mg.h/L and 5.8+/-1.33 mg.h/L, respectively, and the 90% CI of AUC ratios was [0.89+/-0.97]. Thus, exposure to SR26334, and therefore net absorption of clopidogrel, was not significantly modified by food or by prior antacid ingestion.

Adolescent↗

PubMed1994

Comparison of finasteride (Proscar) and Serenoa repens (Permixon) in the inhibition of 5-alpha reductase in healthy male volunteers.

A total of 32 healthy male volunteers (age range 20-30 years) were enrolled in a 1-week open, randomized, placebo-controlled study comparing finasteride (Proscar), a 5 alpha-reductase inhibitor, with Permixon, the plant extract of Serenoa repens. The objective of the study was to evaluate the effect of single and multiple doses of the drugs on the inhibition of 5 alpha-reductase as assessed by serum dihydrotestosterone level determination. Following baseline measurements on day 1, the subjects were randomized to finasteride 5 mg once a day (n = 10), Permixon 80 mg x 2 twice a day (n = 11), or to placebo once a day (n = 11) for 7 days. Serum testosterone and dihydrotestosterone levels, were determined on day 1 (baseline and 12 h) and on days 2 (24 h), 3 (48 h), 4 (72 h), 6 (120 h), and 8 (168 h). After 12 h, a single dose of finasteride 5 mg reduced the serum dihydrotestosterone level by 65% (p < or = 0.01). The decreases ranged from -52 to -60% with multiple doses of finasteride 5 mg once a day (p < or = 0.01). As in the placebo group, there was no effect of Permixon on the serum dihydrotestosterone level. No significant difference was detected between finasteride and Permixon or between finasteride and placebo with respect to serum testosterone, except on days 3 and 6, respectively (p < or = 0.05). However, the corresponding serum testosterone levels remained within the normal ranges. These data confirm the efficacy of finasteride as inhibitor of 5 alpha-reductase.(ABSTRACT TRUNCATED AT 250 WORDS)

5-alpha Reductase Inhibitors↗

PubMed1994

Administration of RU 486 for 8 days in normal volunteers: antiglucocorticoid effect with no evidence of peripheral cortisol deprivation.

New therapeutic indications based on the antiprogesterone action of RU 486 (Mifepristone) are emerging which require long term administration and raise the question of its safety because of the antiglucocorticoid action of the drug. A trial was designed to assess the antiglucocorticoid effect of RU 486, possible manifestations of peripheral cortisol deprivation, and the adrenocortical and corticotroph reserves. Ten normal male volunteers (aged 21-29 yr) were given RU 486 (200 mg/day) or placebo between 0800-0900 h for 8 consecutive days in a randomized, double blind, cross-over design, with a 1-month interval between the two periods. RU 486 induced overactivation of the pituitary-adrenal axis; baseline values (mean +/- SEM) before and at end of treatment were, respectively: 0800 h plasma cortisol, 147.3 +/- 15.5 and 257.6 +/- 8.8 ng/mL; 0800 h salivary cortisol, 5.8 +/- 1.2 and 15.2 +/- 0.8 ng/mL; nocturnal (2200-0800 h) urinary cortisol, 8.4 +/- 1.5 and 33.7 +/- 11.1 micrograms; and 0800 h plasma ACTH, 29.2 +/- 3.7 and 60.2 +/- 8.4 pg/mL. All of these variations were significantly different from those during placebo treatment (0.0001 < P < 0.03) and disappeared within 4 days after the end of treatment. A daily record of subjective clinical symptoms, body weight and temperature, blood pressure, and heart rate showed neither side-effects nor any significant variation during treatment. Blood electrolyte and eosinophil counts were unchanged; fasting blood glucose was slightly higher at the end of treatment (5.0 +/- 0.2 vs. 4.7 +/- 0.1 mmol/L; P = 0.04). The adrenocortical response to Cortrosyn (0.25 mg, im) was exaggerated during RU 486 treatment (P < 0.006): peak values before and at the end of treatment were, respectively: plasma cortisol, 272.5 +/- 15.2 and 347.1 +/- 20.6 ng/mL; and salivary cortisol, 17.0 +/- 2.2 and 31.1 +/- 3.1 ng/mL. Direct pituitary stimulation (100 micrograms ovine CRH, followed by 1 IU lysine vasopressin over 15 min) also induced exaggerated corticotroph and adrenocortical responses (P < 0.005); peak values before and at the end of treatment were, respectively: plasma ACTH, 147.7 +/- 24.6 and 254.0 +/- 41.3 pg/mL; and plasma cortisol, 231.6 +/- 7.3 and 319.2 +/- 12.3 ng/mL. These data show that 8-day treatment with 200 mg RU 486 daily induces a hormonally detectable antiglucocorticoid effect without clinical symptoms. This state results from reversible cortisol overproduction with preservation of adrenocortical and pituitary reserves.

Adrenocorticotropic Hormone↗

PubMed1994

[Ovulation inhibition with medrogestone administered on the 4th through the 24th day of the cycle].

Medrogestone (M) is a derivative of 17 methylprogesterone (P) used for P insufficiency at oral doses of 5 to 15 mg/day (D). We studied the ability of M to inhibit cyclic pituitary-ovarian activity when given at a dose of 10 mg/d from D4 to D24. Ten healthy Caucasian females, aged from 21 to 33, volunteered for an open 2 consecutive cycle study (cycle 1 = control, cycle 2 = M). At inclusion mean (+/- SD) cycle length was 28.6 +/- 1.9 D. Plasma LH, FSH, E2, P, were measured daily from D10 to D20 and at D22, 24, 26. During cycle 1, every subject showed an ovulatory pattern with mid cycle E2 peak (151-400 pg/ml), LH peak (12-59 mUI/ml) and luteal P rise (9.4-22.8 ng/ml). Under M ovulatory surges were suppressed in each of the 10 subjects and P remained below 0.8 ng/ml. These data show that in addition to its known progestomimetic effect, M is a potent ovulation inhibitor when given from D4 to D24 of the cycle.

Adult↗

PubMed1977

Readability - where has it gone?

For the sake of innovation, new typographic devices and styles were introduced in recent years to printed materials that go contrary to the fundamentals of eye physiology and do violence to well-tested and established reading habits. If this trend continues, the saying "Johnny can't read" may have to be modified to "John, at age 50, does not want to read, he rather listens to a tape."

Printing↗