The ability of phosphodiesterase-5 inhibitors sildenafil and ordonafil to reverse L-NAME induced cardiac hypertrophy in the rabbit: possible role of calcineurin and p38.

Phosphodiesterase 5 inhibitors (PDE-5Is) can suppress and (or) reverse pressure overload induced myocardial hypertrophy. This study investigated the suppressive effect of 2 PDE-5Is (sildenafil and ordonafil) on N-nitro-l-arginine methyl ester (L-NAME)-induced cardiac hypertrophy in rabbit heart, and examined their possible mechanism of action. L-NAME increased left ventricular thickness to 6.1± 0.18 mm from 4.6 ± 0.13 mm (p < 0.05), which regressed after treatment with either sildenafil or ordonafil to 5.1 ± 0.1 mm and 4.8 ± 0.2 mm, respectively (p < 0.05). Phenylephrine increased neonatal rat ventricular myocyte cell surface area to 131% ± 3% of the control value, which was associated with significant increment in ERK1/2 to 143% ± 5% of the control value (p < 0.05). Ordonafil and sildenafil decreased cell surface area to 95% ± 3% and 90% ± 1% of the control value, respectively. Both drugs decreased ERK1/2 to 88% ± 4% of the control value. Calcineurin activity was significantly decreased after 1 h of treatment with 0.1 mg·L(-1) ordonafil (1.15 ± 0.05, p < 0.05). For sildenafil (0.1 mg·L(-1)), calcineurin activity significantly decreased only after 24 h of incubation (22%). Also p38 activation was attenuated by ordonafil and sildenafil (0.1 mg·L(-1)). It is suggested that both drugs have the ability to reverse L-NAME-induced cardiac hypertrophy and suppress phenylphrine-induced myocyte hypertrophy, and that these effects may be mediated through the attenuation of calcineurin and its downstream signaling pathways (p38) in neonatal rat ventricular myocytes.

Prevalence and associated factors of cigarette smoking among medical students at King Fahad Medical City in Riyadh of Saudi Arabia.

OBJECTIVE: To determine the prevalence of smoking among medical students at the medical college at King Fahad Medical City in Riyadh, and assess the association between smoking and socio-demographical factors, smoking contacts, reasons for smoking and attempts to quit. MATERIALS AND METHODS: Cross-sectional survey in which anonymous, self-administered questionnaire was used to survey the cigarette smoking habits of the first- and second-year medical students in the Faculty of Medicine, King Fahad Medical City in June 2009. RESULTS: Overall 39.8 % of the investigated students (153) had smoked before, and 17.6% were current smokers. The mean age of initiating smoking was 15.8 (±3.3). There were significantly more males than females. The most important reasons for smoking were leisure, imitation of other people and a means of relieving psychological pressure. Reasons for not smoking were mostly health and religion-based. Smokers tended to have friends who smoked. CONCLUSION: Cigarettes smoking is highly prevalent among medical students in the Faculty of Medicine, King Fahad Medical City. Contact with smokers particularly friends are the major risk factors for the initiation of the habit. Health and religious considerations are important motives for not smoking, quitting or attempting to quit. These findings can be of help in designing future intervention strategies.

Gender differences in smoking behavior among adolescents in Saudi Arabia.

OBJECTIVE: To describe and assess gender differences in current cigarette smokers' according to certain variables including prevalence, access to tobacco, knowledge and attitude, environmental tobacco smoke, cessation of smoking, tobacco related advertisements, and education on tobacco in school among adolescents in grades 7-12 in Tabuk, Saudi Arabia. METHODS: A random sample of schools in Tabuk city was obtained using a 2-stage cluster, in April 2005. A total of 16 governmental schools were selected. Within the schools, 48 classes were selected, targeting grades was 7 to 12. An anonymous, self-administered questionnaire was used to select 1,505 participants, with 96% response rate. RESULTS: Out of 1,505 students, 22.3% (34% males, 11.1% females) were current cigarette smokers (students who had smoked on one or more days in the 30 days preceding the survey), and 5.8% (11.1% males, 0.7% females) were daily smokers. There were significant gender differences concerning source of cigarettes, usual place of smoke, intensity of smoking, knowledge on addiction of tobacco, exposure to education on tobacco, attitudes, and exposure to tobacco smoke in public places. While no significant gender differences were found with respect to age of initiation, knowledge of health hazards of tobacco, exposure to media, desire to quit, or exposure to tobacco smoke at home. CONCLUSION: For the suppression of the use of tobacco by adolescents in Saudi Arabia differential intervention strategies and policies in males and females are needed, such as reducing youth access to cigarettes-in addition to intensive school and community anti-tobacco programs.