Desmin: molecular interactions and putative functions of the muscle intermediate filament protein

Desmin is the intermediate filament (IF) protein occurring exclusively in muscle and endothelial cells. There are other IF proteins in muscle such as nestin, peripherin, and vimentin, besides the ubiquitous lamins, but they are not unique to muscle. Desmin was purified in 1977, the desmin gene was characterized in 1989, and knock-out animals were generated in 1996. Several isoforms have been described. Desmin IFs are present throughout smooth, cardiac and skeletal muscle cells, but can be more concentrated in some particular structures, such as dense bodies, around the nuclei, around the Z-line or in costameres. Desmin is up-regulated in muscle-derived cellular adaptations, including conductive fibers in the heart, electric organs, some myopathies, and experimental treatments with drugs that induce muscle degeneration, like phorbol esters. Many molecules have been reported to associate with desmin, such as other IF proteins (including members of the membrane dystroglycan complex), nebulin, the actin and tubulin binding protein plectin, the molecular motor dynein, the gene regulatory protein MyoD, DNA, the chaperone alphaB-crystallin, and proteases such as calpain and caspase. Desmin has an important medical role, since it is used as a marker of tumors' origin. More recently, several myopathies have been described, with accumulation of desmin deposits. Yet, after almost 30 years since its identification, the function of desmin is still unclear. Suggested functions include myofibrillogenesis, mechanical support for the muscle, mitochondrial localization, gene expression regulation, and intracellular signaling. This review focuses on the biochemical interactions of desmin, with a discussion of its putative functions.

Indice de función sexual femenina: un test para evaluar la sexualidad de la mujer

Objetivo. Aplicar y validar en una población chilena el "Indice de Función Sexual Femenina" establecido en el International Consensus Development Conference on Female Sexual Dysfunctions. Material y método. 383 mujeres sanas de 20 a 59 a¤os con actividad sexual, beneficiarias del Centro de Salud "Carol Urzúa". Instrumento: cuestionario de 19 preguntas, agrupadas en seis dominios: deseo, excitación, lubricación, orgasmo, satisfacción y dolor. Análisis estadístico: Se utilizó ANOVA, Kruskall-Wallis, Chi cuadrado, regresión logística y alpha de Cronbach. Resultados. Edad media: 35,3ñ10,9 a¤os, casadas (50,4 por ciento) o conviviente (17,0 por ciento), con educación media (48,2 por ciento). La consistencia interna del test fue buena (>0,70). La sexualidad logra su máxima expresión a los 35-40 a¤os (puntaje: 29,1ñ4,9) para caer posteriormente (21,0ñ6,0), especialmente el deseo y excitación. Después de los 44 a¤os se incrementa el riesgo de disfunción sexual (OR:3,6; IC: 2,1-6,3; p< 0,0001). La mayor educación y la estabilidad de pareja disminuyen el riesgo (OR: 0,45; IC:0,28-0,80; p< 0,005 y OR:0,58; IC:0,35-0,98; p< 0,05 respectivamente). Conclusiones. El Indice de Función Sexual Femenino es un instrumento sencillo de aplicar, con propiedades psicométricas adecuadas que permite evaluar la sexualidad en diferentes etapas de la vida. Es adecuado para estudios epidemiológicos y clínicos.

Tumor promoter-like activity of the molluscicidal latex of 'Crown-of-Thorns' (Euphorbia milii var. hislopii) in the V79 metabolic cooperation assay

The latex of 'Crown-of-Thoms'(Euphorbia miliivar. hislopii, syn. E. splendens) has been shown to be a potent plant molluscicide that could be used against the snails which are intermediate hosts of Schistosoma trematodes. However, a comprehensive toxicological evaluation of the latex is necessary before its large-scale use in schistosomiasis control becomes possible. In fact, one cause for concern is the presence of tumor-promoting phorbol esters in several plants of the Euphorbiaceae family. Phorbol esters as well as a number of other known tumor promoters share the common property of inhibiting metabolic cooperation (i.e., exchange of low molecular weight molecules via gap junctions) between Chinese hamster V79 cells in monolayer cultures. The present study was undertaken to determine if latex of E. milii presents tumor promoter-like activity in this shortterm in vitro assay. Samples of lyophilized E. milii latex were tested at a noncytotoxic concentration range (1, 10, 50 and 100 mug/ml) in three independent experiments. 12-0-Tetradecanoylphorbol-13-acetate (10 ng/ml) was used as positive control. In all three assays, E. milii latex consistently inhibited metabolic cooperation between V79 cells at concentrations (10 mug/ml. These results indicate that E. milii latex contains tumor-promoting substances. These findings suggest that the use of crude latex as a molluscicide may pose a carcinogenic hazard to people who are continuously exposed to the product.