ABSTRACT
La proteía C reactiva ha sido ampliamente usada en el diagnóstico y seguimiento de diversas enfermedades; sin embargo, es necesario conocer cómo se produce este reactante de fase aguda, sus características y comportamiento en las distintas condiciones clínicas. La proteína C reactiva tiene importantes ventajas por la rapidez y magnitud de sus cambios; sus limitaciones se relacionan con el hecho de ser parte de la respuesta inflamatoria desencadenada por distintos mecanismos infecciosos y no infecciosos. Por esta razón, debe ser usada racionalmente en el marco de una enfermedad y en asociación con otras pruebas diagnósticas, llegando a ser un aporte valioso en el proceso de diagnóstico y seguimiento de distintas entidades, al igual que en la vigilancia postoperatoria y de transplantes, además permanece inalterada en presencia de desnutrición o inmunodeficiencia.
Subject(s)
Humans , Inflammation , Protein C/isolation & purification , Protein C/ultrastructure , Protein CABSTRACT
We examined the axial repeats in electron micrographs of three types of negatively stained paracrystals (two tactoid- and one sheet-like type) of rabbit light meromyosin (LMM) and its complex with C-protein characterized previously by similar axial period of about 43.0 nm. Assuming for the axial repeat in type II tactoids the value of 42.93 +/- 0.05 nm as it was determined by X-ray diffraction technique (Yagi and Offer 1981), we found average axial repeats in type I tactoid and in sheet-like paracrystal of 42.93 +/- 0.75 nm and 43.50 +/- 0.62 nm respectively. Analyzing the micrographs where the two types paracrystals are located side-by-side we determined rather accurately the average ratio of axial repeat in sheet-like paracrystal to that in type I tactoid (1.013 +/- 0.002). Taking 42.93 nm as the axial repeat in type I tactoid, the axial repeat in sheet-like paracrystal was found to be 43.50 +/- 0.08 nm. C-protein binds to LMM with the period of the underlying LMM paracrystals and independently of the value of their axial repeats. Two different axial repeats (42.9 nm and 43.5 nm) revealed for LMM paracrystals in this study precisely coincide with the average repeat periods of myosin crossbridges along the thick filaments found for different physiological states of skeletal muscles (Lednev and Kornev 1987). Molecular basis for the appearance of two structural states in LMM paracrystals and in the shafts of thick filaments are discussed.
