The quantity of bone marrow collected for allogeneic bone marrow transplantation is based on collecting 10 to 15 cc of bone marrow/kg of recipient weight. We hypothesized that the percentage of CD34+ cells collected during a bone marrow harvest decreased at the end of the harvest because of increasing amounts of peripheral blood contamination. We performed a prospective, blinded study in which we measured CD34+ percentages and cell counts at 200-cc intervals during bone marrow harvests from 11 consecutive human leukocyte antigen (HLA)-matched sibling bone marrow donors. We observed that the percentage of CD34+ cells in aspirated bone marrow did not vary significantly from the start to the end of the bone marrow harvest, and the total number of CD34+ cells/kg increased in a linear fashion, thus disproving our original hypothesis. In conclusion, the percentage of CD34+ cells in aspirated bone marrow will remain constant throughout a bone marrow harvest.

ResumenIntroducción y objetivo: en la actualidad, las investigaciones encaminadas a mejorar la salud cardiovascular de las personas son de suma importancia. Este artículo se centra en estudiar los efectos de un programa de actividad física sobre la tensión arterial y frecuencia cardiaca de un grupo de adolescentes. Método: participaron 38 adolescentes (14 hombres y 24 mujeres), entre los 12 y los 15 años de edad (media de edad 13,61 y DE 1,00). Las variables estudiadas fueron: tensión arterial (sistólica y diastólica) y frecuencia cardiaca en reposo. La tensión arterial y la frecuencia cardiaca se midieron con el tensiómetro de brazo Visomat Comfort 20/40. El procedimiento ha sido: pre-test, intervención y pos-test. La intervención ha consistido en tres días a la semana de actividad física de alta intensidad, 15 minutos al día, durante 12 semanas. Resultados: se ha realizado un análisis de datos por medio del SPSS 22 y se han obtenido mejoras significativas en la tensión arterial y la frecuencia cardiaca (Sig. < 0.05). Conclusiones: el programa de actividad física empleado en este estudio se presenta como una herramienta útil para mejorar la tensión arterial y la frecuencia cardiaca de adolescentes.Palabras clave: Escolares, Educación Física, Salud Cardiovascular. AbstractIntroduction and objective: research focused on the improvement of cardiovascular health is very important nowadays. This paper focuses on studying the effects of a physical activity program on the blood pressure and heart rate of a group of adolescents. Method: This investigation involved 38 adolescents (14 males and 24 females), ages between 12 and 15 years old (average age 13.61 and standard deviation 1.00). The variables considered were: blood pressure (systolic and diastolic) and resting heart rate. Blood pressure and heart rate were measured by a Visomat Comfort 20/40 arm sphygmomanometer. The procedure was as follows: pre-test, intervention and pos-test. The intervention consisted of 3 days per week of high-intensity physical activity, 15 minutes per day, during 12 weeks. Results: Data was analyzed through the SPSS 22 and significant improvements were obtained in blood pressure and heart rate (Sig <0.05). Conclusions: The physical activity program implemented in this study is a useful tool to improve blood pressure and heart rate in adolescents.