Chromosome damage induced by DNA topoisomerase II inhibitors combined with g-radiation in vitro

Combined radiation and antineoplastic drug treatment have important applications in cancer therapy. In the present work, an evaluation was made of two known topoisomerase II inhibitors, doxorubicin (DXR) and mitoxantrone (MXN), with g-radiation. The effects of DXR or MXN on g-radiation-induced chromosome aberrations in Chinese hamster ovary (CHO) cells were analyzed. Two concentrations of each drug, 0.5 and 1.0 µg/ml DXR, and 0.02 and 0.04 µg/ml MXN, were applied in combination with two doses of g-radiation (20 and 40 cGy). A significant potentiating effect on chromosomal aberrations was observed in CHO cells exposed to 1.0 µg/ml DXR plus 40 cGy. In the other tests, the combination of g-radiation with DXR or MXN gave approximately additive effects. Reduced mitotic indices reflected higher toxicity of the drugs when combined with radiation.<br>A associação de radiação ionizante com drogas antineoplásicas tem importante aplicação na terapia do câncer. No presente trabalho, foram avaliados os efeitos de dois inibidores de topoisomerase II, doxorubicina (DXR) e mitoxantrona (MXN), sobre as aberrações cromossômicas induzidas pelas radiações-g em células do ovário de hamster chinês (CHO). Foram usadas as concentrações 0,5 e 1,0 mg/ml de DXR e 0,02 e 0,04 mg/ml de MXN, combinadas com duas doses de radiações gama (20 e 40 cGy). Um significativo efeito potenciador das aberrações cromossômicas foi observado em células CHO tratadas com 1,0 mg/ml de DXR e expostas a 40 cGy de radiação. Nos outros testes, a combinação da radiação-g com a DXR ou MXN apresentou um efeito próximo ao aditivo. A redução dos índices mitóticos refletiu a alta citotoxicidade das drogas quando combinadas às radiações-g

Brown in Black and White—Then and Now

The U.S. Supreme Court\u27s decision in the Brown v. Board of Education case was used as a point of reference to elaborate on the often divergent realities in education and sport for Black and White Americans. The impetus to integrate sport and the movement to integrate educational institutions in America were two separate yet often paralleled phenomena. It is typically argued that efforts to integrate educational institutions were about ensuring equitable access and opportunity. Less so, due to moral principles, integration in sports was more about winning and generating revenue. Still today, race-related divergences are reflected in education and sport. The intent of this article is to reflect on America\u27s education and sport histories (then) and highlight some present-day realities (now) as associated with the social construct of race, particularly for Black male students and athletes. © 2008 Sage Publications