Problemas bioéticos en la investigación de nuevas vacunas: ¿obedecen a razones de salud pública? / Bioethical problems in researching new vaccines: Do they respond to public health reasons?

Los problemas éticos de las investigaciones sobre vacunas han crecido en las últimas décadas en frecuencia y magnitud debido a la posición dominante de la industria farmacéutica en el desarrollo de esos estudios. Las tradicionales cuestiones de seguridad y eficacia se han visto agravadas por el conflicto de intereses introducido por la competencia comercial en un mercado a escala global de miles de millones de dólares. La integridad profesional de los investigadores, la responsabilidad moral de los patrocinadores, y la regulación y control por parte de los Estados nacionales, se muestra cuestionada en varios ejemplos. Los resultados de estos cambios son las amenazas a la protección de los derechos de las personas incluidas en estas investigaciones y el discutible progreso que resulta para la salud pública.

The ethical problems in vaccine research have grown in frequency and magnitude in last decades, due to the dominant place of the pharmaceutical industry in the development of such studies. Traditional issues of security and efficacy have been aggravated by the conflicts of interests introduced by commercial competition in a global market worth billions of dollars. We present here a few examples in which the professional integrity of researchers, the moral responsibility of sponsors, and the public regulation and control by national States are put into question. The consequences of these changes represent serious threats to the rights of people included in these studies as well as disputable progress for public health.

Effect of psychological stress on the L-arginine-nitric oxide pathway and semen quality

It has been reported that mental stress causes abnormality of spermiogram parameters. We investigated the effect of psychological stress on the L-arginine-nitric oxide (NO) pathway. Semen samples were collected from 29 healthy fourth semester medical students just before (stress) and 3 months after (non-stress) the final examinations. Psychological stress was measured by the State Anxiety Inventory questionnaire. After standard semen analysis, arginase activity and NO concentration were measured spectrophotometrically in the seminal plasma. Measurements were made in duplicate. During the stress period, sperm concentration (41.28 ± 3.70 vs 77.62 ± 7.13 x 10(6)/mL), rapid progressive motility of spermatozoa (8.79 ± 1.66 vs 20.86 ± 1.63 percent) and seminal plasma arginase activity (0.12 ± 0.01 vs 0.22 ± 0.01 U/mL) were significantly lower than in the non-stress situation, whereas seminal plasma NO (17.28 ± 0.56 vs 10.02 ± 0.49 æmol/L) was higher compared to the non-stress period (P < 0.001 for all). During stress there was a negative correlation between NO concentration and sperm concentration, the percentage of rapid progressive motility and arginase activity (r = -0.622, P < 0.01; r = -0.425, P < 0.05 and r = -0.445, P < 0.05, respectively). These results indicate that psychological stress causes an increase of NO level and a decrease of arginase activity in the L-arginine-NO pathway. Furthermore, poor sperm quality may be due to excessive production of NO under psychological stress. In the light of these results, we suggest that the arginine-NO pathway, together with arginase and NO synthase, are involved in semen quality under stress conditions.

Association between mental stress & some antioxidant enzymes of seminal plasma.

BACKGROUND & OBJECTIVE: Mental stress, which is responsible for various disorders, is one of the most important medical and social problems. It is reported that mental stress causes abnormality in sperm quality. Most of the previous investigations done to study the association between mental stress and infertility were carried out with infertile men. Infertility itself and/or its therapy may lead to stress. Further, most studies investigating the association between psychological stress and semen quality have lacked information on biochemical parameters. In the present study, we investigated the effect of mental stress due to final exams on two important antioxidant enzymes of the seminal plasma, superoxide dismutase (SOD) and catalase in normal healthy medical students. METHODS: Semen samples were collected from 27 healthy male volunteers, who were third semester students of a medical school, just before (stress period) and 10.19+/-0.83 wk after (non-stress period) the final examinations. Psychological stress of participants was measured by the State Trait Anxiety Inventory. After standard semen analysis, semen samples were centrifuged at 10,000 x g for 15 min. Superoxide dismutase (SOD) and catalase activities were measured in the seminal plasma. RESULTS: During stress period, stress scores and SOD activities increased significantly compared to the non-stress period. Catalase activities showed no change. Spermatozoa concentrations, motility index and percentage of rapid progressive motility decreased under stress. INTERPRETATION & CONCLUSION: Our results indicated that mental stress negatively affected semen quality. Increase in SOD activities led to poor quality of semen parameters.