The Magnetic Resonance Imaging (MRI) is a non-invasive technique which uses the physical phenomenon of nuclear magnetic resonance to obtain structural and compositional information about human body regions. In this imaging study we use the radio-frequency and a powerful static magnetic field, which aligns the magnetization of hydrogen nuclei. Nowadays there are many types of clinical equipment that conduct MRI studies, which have intensities of magnetic fields from 0.2T to 7.0T. Moreover, liquid helium is required for the superconducting coil. This paper presents an analysis of the magnetic resonance phenomenon; by doing a review of the quantum-mechanical aspects as the spin and Zeeman effect.

Aims: To describe postoperative morbidity and mortality rates in multivisceral resections for T4b colon cancer. Material and methods: Case series of patients diagnosed of T4b colonic adenocarcinoma who underwent multivisceral resection between 2005 and 2014. There were excluded those patients who had metastases, R2 resection and incomplete clinical data. Result variables were morbidity and mortality at 30 days. It was performed descriptive statistic using percentage estimation for categories, average and median for continuous variables and standard deviation or rank as measures of statistical dispersion. It was used Kaplan-Meier method for survival and chi-square and log-Rank for subgroups analysis. Results: From a universe of 483 patients who underwent surgery for colonic adenocarcinoma, whom 71 were staged as T4b, after exclusion criteria were applied it resulted a sample of 46 patients. The small bowel, omentum, abdominal wall and other colonic segment were the more often compromised organs. Postoperative morbidity and mortality were 21.7 and 6.5% respectively. The age, history of adjuvant chemotherapy, presence of microsatellite instability and tumor differentiation had a significant impact in survival. Conclusions: Multivisceral affection in colonic cancer is not uncommon, 9.5% in our series. R0 resection is the treatment of choice. Patient outcome depends on his age, histologic and biologic characteristics of the tumor and adjuvant treatment.

Objetivos: Describir las tasas de morbilidad y mortalidad postoperatorias de las resecciones ampliadas de colon en pacientes con tumor en estadio T4b. Material y métodos: Serie de casos, que incluye pacientes con adenocarcinoma colónico clínicamente con compromiso de estructuras adyacentes (T4b), intervenidos de resección multivisceral entre los años 2005 y 2014. Fueron excluidos pacientes con metástasis, con bordes macroscópicamente comprometidos y con datos clínicos incompletos. Las variables resultado fueron la morbilidad y mortalidad postoperatorias a los 30 días. Se aplicó estadística descriptiva. Para las variables categóricas se utilizaron porcentajes, y para las variables continuas se utilizaron la media y mediana como medidas de tendencia central y la desviación estándar o rango como medidas de dispersión. Se aplicó el método de Kaplan-Meier para la sobrevida, y pruebas de Chi cuadrado y log-Rank para el análisis de sobrevida por subgrupos. Resultados: De un universo de 483 pacientes intervenidos por adenocarcinoma colónico, 71 fueron T4b. Se aplicaron criterios de exclusión, resultando una muestra de 46 pacientes. Los órganos más frecuentemente comprometidos fueron: intestino delgado, epiplón, pared abdominal y otro segmento colónico. La morbilidad y mortalidad postoperatorias, de un 21,7 y un 6,5%, respectivamente. Influyeron significativamente en la sobrevida la edad, el antecedente de quimioterapia adyuvante, la presencia de inestabilidad microsatelital y la diferenciación del tumor. Conclusiones: El compromiso multivisceral de los tumores colónicos no es infrecuente, con un 9,5% para nuestra serie. La resección R0 es el tratamiento de elección. Influyen en el pronóstico el tipo histológico y el comportamiento biológico del tumor, así como la quimioterapia adyuvante y la edad del paciente.

Angiotensin-(1-7) (Ang-(1-7)) increased osmotic water permeability in the isolated toad skin, a tissue with functional properties similar to those of the distal mammalian nephron. Concentrations of 0.1 to 10 µM were effective, with a peak at 20 min. This effect was similar in magnitude to that of frog skin angiotensin II (Ang II) and oxytocin but lower than that of human Ang II and arginine-vasotocin. The AT2 angiotensin receptor antagonist PD 123319 (1.0 µM) fully inhibited the response to 0.1 µM Ang-(1-7) but had no effect on the response to Ang II at the same concentration. The specific receptor antagonist of Ang-(1-7), A-779, was ineffective in blocking the response to Ang-(1-7) and to frog skin Ang II. The AT1 receptor subtype antagonist losartan, which blocked the response to frog skin Ang II, was ineffective in blocking the response to Ang-(1-7). The present results support the view of an antidiuretic action of Ang-(1-7) in the mammalian nephron.