Oxidative stress and diabetic retinopathy: development and treatment.

Diabetic retinopathy (DR) is the most common microvascular complication in diabetic patients and one of the main causes of acquired blindness in the world. From the 90s until date, the incidence of this complication has increased. Reactive oxygen species (ROS) is a free radical with impaired electron that usually participates in the redox mechanisms of some body molecules such as enzymes, proteins, and so on. In normal biological conditions, ROS is maintained in equilibrium, however its overproduction can lead to biological process called oxidative stress and this is considered the main pathogenesis of DR. The retina is susceptible to ROS because of high-energy demands and exposure to light. When the balance is broken, ROS produces retinal cell injury by interacting with the cellular components. This article describes the possible role of oxidative stress in the development of DR and proposes some treatment options based on its stages. The review of the topic shows that blindness caused by DR can be avoided by early detection and timely treatment.

Effects of two new steroids and cyproterone on some biomarkers of oxidative stress and serotonergic system on rat prostate and brain.

The purpose of this study was to evaluate the effect of cyproterone acetate (CPA, A) compared with new synthetic steroids 3alpha-acetoxy-5,6-epoxy-16-pregnen-20-one (B) and 17alpha-hydroxy-16beta-methyl-1,4,6-pregnatriene-3,20-dione (C) in rat prostate and brain. Groups of animals were treated either with A, B or C (4 mg kg(-1) day(-1)) by the intraperitoneal route for 5 days. Levels of reduced glutathione (GSH), 5-hydroxy-indole acetic acid (5-HIAA), lipid peroxidation (as thiobarbituric acid reactive substances, TBARS) and the activities of Na(+), K(+)- and total ATPases were assayed in prostate and brain for each group of animals including a control group. No appreciable changes were shown in Na(+), K(+)-ATPase and total ATPases and TBARS on prostate and brain of rats that received A, B and C steroids. However, the levels of GSH and 5-HIAA decreased significantly (P < 0.05) in both tissues for the steroids assayed. It is concluded that CPA and the homologues B and C steroids induce changes in the levels of GSH and serotonin in rat prostate and brain.

Age-density dependent population dispersal in RN.

We discuss an N-dimensional model for diffusion of age dependent populations. Let rho(x, t, a) be the population density at time t, age a and spatial position x, and let u(x, t) = [formula: see text] rho(x, t, a) da be the total population at t and x. The directed dispersal model to be discussed, with diffusion depending on the gradient of the total population, is [formula see text] With some assumptions on the form of the death and birth modulus, this system is reduced to a mixed parabolic-hyperbolic system containing the Porous Medium equation in RN. We discuss the existence, regularity and localization of the solution of this reduced system.

Broncoscopia en el diagnóstico del cáncer broncogénico / Broncoscopy in the diagnosis of bronchogenic carcinoma

Se presentan los resultados obtenidos con el estudio broncoscópico de 637 pacientes con carcinoma broncogénico. Las imagenes broncoscópicas observadas fueron: masa tumoral, estenosis bronquial, hemorragia y mucosa de aspecto normal. El pulmón derecho fue el más afectado con 203 casos, mientras que en el izquierdo se presentaron 11. En la tráquea se encontraron tumoraciones en 31 enfermos. Se señalan los sitios de las vías aéreas donde se localizaron estas alteraciones y su frecuencia. El estudio citológico del lavado y cepillado bronquial mediante broncoscopia evidenció 181 casos con células neoplásicas, cifra que se incrmentó en un 3.4 por ciento en muestras de concentrado de expectoración en líquido de carbowax en los días subsecuentes a la broncoscopia. Se efectuaron 348 biopsias bronquialeas durante el estudio broncoscópico, encontrando que el tipo histológico de cáncer más frecuente correspondió al epidermoide con 165 casos, seguido del adenocarcinoma con 143. Se considera que la fibrobroncoscopia es un método seguro y que debe efectuarse en los pacientes con sospecha clínica de padecer cáncer pulmonar

Dynamics of populations with age-difference and diffusion: localization.

"In this paper we study the behavior of the solutions of the Gurtin-MacCamy model for the dynamics of populations with [spatial] diffusion and age-dependence. We give sufficient conditions on the birth and death modules for the population to remain localized in a fixed interval or to ultimately cover all the domain."