Inflammation in the vascular bed: importance of vitamin C.

Despite decreases in atherosclerotic coronary vascular disease over the last several decades, atherosclerosis remains a major cause of mortality in developed nations. One possible contributor to this residual risk is oxidant stress, which is generated by the inflammatory response of atherosclerosis. Although there is a wealth of in vitro, cellular, and animal data supporting a protective role for antioxidant vitamins and nutrients in the atherosclerotic process, the best clinical trials have been negative. This may be due to the fact that antioxidant therapies are applied "too little and too late." This review considers the role of vitamin C, or ascorbic acid in preventing the earliest inflammatory changes in atherosclerosis. It focuses on the three major vascular cell types involved in atherosclerosis: endothelial cells, vascular smooth muscle cells, and macrophages. Ascorbate chemistry, recycling, and function are described for these cell types, with emphasis on whether and how the vitamin might affect the inflammatory process. For endothelial cells, ascorbate helps to prevent endothelial dysfunction, stimulates type IV collagen synthesis, and enhances cell proliferation. For vascular smooth muscle cells, ascorbate inhibits dedifferentiation, recruitment, and proliferation in areas of vascular damage. For macrophages, ascorbate decreases oxidant stress related to their activation, decreases uptake and degradation of oxidized LDL in some studies, and enhances several aspects of their function. Although further studies of ascorbate function in these cell types and in novel animal models are needed, available evidence generally supports a salutary role for this vitamin in ameliorating the earliest stages of atherosclerosis.

Development of a low-color, color stable, dual cure dental resin.

UNLABELLED: Dual-cure (DC) resins are mainly used as cements due to high initial color (generally yellow) and large color shift (ΔE*) after polymerization as compared to light-cured resins. However, even as cements, this color shift is clinically unacceptable, especially when used to cement thin veneers. OBJECTIVE: To develop a novel DC initiator system with both lower initial color (less yellow, i.e., whiter) and smaller ΔE*. METHODS: The effect of using an allyl thiourea (T)/cumene hydroperoxide (CH) self-cure (SC) initiator system in combination with a photo-co-initiator, p-octyloxy-phenyl-phenyl iodonium hexafluoroantimonate (OPPI), in a commercial DC resin cement (PermaFlo DC, Ultradent Products, Inc.) was investigated. Initial color and ΔE* were assessed for 6 weeks in vitro under accelerated aging conditions (75°C water bath). Rockwell15T hardness was used to assess degree of cure (DoC) and the three-point bending test was used to assess mechanical properties. RESULTS: PermaFlo DC (control) was significantly harder than all experimental groups without OPPI but had up to three times higher initial color and four times greater color shift (ΔE*=27 vs. 8). With OPPI, hardness in the experimental groups increased significantly and several were comparable to the controls. Initial color and ΔE* increased slightly (ΔE*=9), but was still 3 times less than that of PermaFlo DC. DC samples containing OPPI had comparable modulus and ultimate transverse strengths to those of the controls. CONCLUSIONS: DC resins that use the T/CH initiator system are weaker but have extremely low color and ΔE*. The addition of OPPI increases DoC and mechanical properties to clinically acceptable levels and maintains extremely low color and ΔE*. SIGNIFICANCE: With this novel initiator system, DC resins potentially can now have comparable color and color stability to light-cure resins and be used in broader esthetic dental applications to improve color stability and reduce shrinkage stress in restorative composites.

Utilidad del ultrasonido en la detección de patología biliar: unidad de imagenología-Hospital de Clínicas, La Paz enero 2004 / Unit of imagenology - Hospital of Clinical La Paz janury 2004

Las nuevas técnicas de diagnóstico como el ultrasonido, que tienen los equipos de tiempo real, permiten obtener una información cómoda, barata y rápida, del estado del sitema biliar, así como el estudio del páncreas, hígado y otras estrcuturas anatómicas vecinas como el riñon derecho. El ultrasonido (US) permite demostrar la vesícula biliar en un 98 por ciento. y la precencia de cálculos en su interior con una fiabilidad diagn´sotica por encima del 99 por ciento. De ésta manera en la actual ha reemplazado a la colecistográfia. En la generalidad de los casos representa la primera exploración en pacientes con patología biliar. El mayor problema que se enfrenta el ecografista es la falta de visualización de la vesícula biliar y que obedecen a varios factores , como la presencia de gases intestinales, falta de un ayuno prolongado, vesícula escleroatrófica, agenesia, etc. En el servicio de Ecografía del Hospital de Clínicas de la ciudad de La Paz se atendieron en el mes de enero de 2004 un total de 331 paaciaentes de ambos sexos con edades comprendidad ente los 10 y 83 años procedentes de diferentes servicios, por diversas patologías; con diagnósticos (32 por ciento) y otros sin un diagnóstico clínico (78 por ciento) procedentes la Unidad de Urgencias. De los331 pacientes fueron :228 mujeres y 103 varones. El 40 por ciento correspondieron a pacientes con patología biliar, diagnosticados por ultrasonidos, con una alta significación estadística, y una sensibilidad y especialidad diagnóstica del 98 por ciento.

Presentación caso clinico radiológico unidad imagenologia, Hospital de clínicas 2003 / Presentation clinico case radiological unit imagenologia, Hospital of clinics 2003

La presentación clínica de un caso de tumor abdominal de una serie de estudios de patologías tumorales de abdomen efectuados en la Unidad de Imagenología del Hospital de Clínicas (La Paz- Bolivia) pretende demostrar una alternativa en cuanto al diagnóstico por imágenes de masas abdominales antes de llegar a una cirugia o tratameinto oncológico.