Diabetes melito, tiazolidinedionas e fraturas: uma história inacabada / Diabetes mellitus, thiazolidinediones and fractures: an unfinished story

A associação entre diabetes melito e risco aumentado de fraturas é bem estabelecida, sendo observada tanto no diabetes tipo 1 quanto tipo 2, com etiologia multifatorial. Evidências de modelos animais têm indicado que tiazolidinedionas (TZD), por meio da ativação do PPAR-gama, levam a aumento do conteúdo adiposo na medula óssea, em detrimento da osteoblastogênese, resultando em perda óssea. Estudos iniciais em humanos vêm evidenciando maior risco de fraturas na população em uso dessas medicações em relação a outros antidiabéticos orais. Sendo TZD drogas amplamente prescritas no tratamento do diabetes tipo 2, é necessário melhor entendimento dos seus mecanismos de ação e do seu impacto sobre a massa óssea e risco de fraturas, com o intuito de direcionar a abordagem desses pacientes quanto à profilaxia e ao tratamento adequados. Este artigo sumariza o conhecimento corrente sobre a relação entre diabetes, TZD e risco de fraturas, bem como, baseado nas evidências atuais, tenta propor formas de conduzir a população em uso dessas medicações.

The association of diabetes mellitus with increased fracture risk is well established, and is observed in both diabetes type 1 and type 2, due to multiple causes. Evidence from rodents suggests that thiazolidinediones (TZD), by activation of PPAR-gamma, cause increased bone marrow adiposity, with decreased osteoblastogenesis resulting in bone loss. Initial studies in humans evidence higher fracture risk in the population using these drugs, in comparison with other oral antidiabetic medications. TZD are largely prescribed for the treatment of type 2 diabetes, therefore, better understanding of their mechanisms of action and impact on bone mass and fracture risk is necessary, in order to guide the management of these patients in regards to prophylaxis and adequate treatment. This article summarizes current knowledge about the relationship between diabetes, TZD and fracture risk as well as, based on current evidence, tries to suggest ways to guide the population using these medications.

Metodología de construcción de muslos 3D para estimar variables eléctricas inducidas por campos magnéticos de baja frecuencia / Methodology for building 3D model of trigh to estimate electric variable induced by low-frequency magnetic fields

La construcción de modelos geométricos de tejidos biológicos es un tema de investigación actual, ya que permiten estimar y evaluar a priori señales de interés para ser posteriormente llevadas a estudios experimentales, ahorrando tiempos de investigación y dinero. En este artículo se presenta una metodología para la construcción de modelos 3D de muslo con fractura de diáfisis femoral estimulados magnéticamente. La metodología utiliza tres herramientas computacionales para crear el modelo del muslo del paciente y la fuente de estimulación. El modelo 3D del muslo considera seis modelos volumétricos personalizados de: piel, músculo, hueso cortical, médula, clavo y la forma de fractura. Las propriedades eléctricas para el muslo son anisotrópicas. La fuente feneradora es una bobina Helmholtz circular cuyo radio varía con el diámetro del muslo del paciente. Las señales de estimulación varían entre 0,5 y 2 mT, y entre 5 y 100 Hz. Las señales evaluadas fueron el campo magnético. Los resultados indicaran que la densidad de corriente inducida aumentó hasta 500 veces mientras el campo eléctrico inducido po presentó cambios quando la frecuencia aumentó de 5 a 100 Hz. Qucando el campo magnético incrimentó de 0,5 mT a 2 mT, la densidad de corriente inducida aumentõ has 15 veces mientras el campo eléctrico inducido aumentó has 22 veces.

A Cohort Study on the Association between Psychotropics and Hip Fracture in Korean Elderly Women

To test the hypothesis that the intake of psychotropics may increase the risk of hip fracture, a cohort study was conducted upon elderly Korean women. The Korean Elderly Pharmacoepidemiology Cohort was constructed from members of the Korea Medical Insurance Corporation over 65 yr of age who were living in Busan Metropolitan City in 1993. Study participants (n=6,043) were female respondents to a self-administered question survey. Information on the intake of psychotropics was obtained from the drug prescription database, which contained all psychotropic prescriptions during any hospital admission over the two-year period between January 1, 1993 and December 31, 1994. The cohort follow-up has been conducted with information on hip fracture being collected from the Korea Medical Insurance Corporation medical treatment claims database over the four year period between January 1, 1993 and December 31, 1996. Three hundred and three subjects had received 745 psychotropics prescriptions and 56 cases of hip fracture were found. After adjusting for age, body mass index, and drinking history, it was found that the intake of psychotropics significantly increased the risk of hip fracture (adjusted odds ratio, 4.24; 95% confidence interval, 1.89-9.52). This study suggests that the intake of psychotropics might be an important risk factor for hip fracture in elderly Korean women.