ABSTRACT
Las mielopatías agudas representan un grupo heterogéneo de enfermedades, de distintas etiologías, hallazgos clínicos y radiológicos diferentes, y particular pronóstico. La Mielitis transversa (MT), es el prototipo del grupo, en el cual, un proceso inmunitario causa el daño neural en la médula espinal, resultando en varios grados de paresia, alteraciones sensitivas, y disfunción autonómica. La MT puede existir como parte de una enfermedad del Sistema nervioso Central multifocal (Esclerosis múltiple) enfermedad multisistémica (Lupus Eritematoso Sistémico), o aislada, como una entidad idiopática. En este artículo, presentamos un caso clínico, y revisamos recientes esquemas diagnósticos, que permiten sistematizar el diagnóstico y tratamiento de los pacientes con mielopatía aguda. Adicionalmente, resumimos el estado actual del conocimiento acerca de la epidemiología, historia natural de la enfermedad, inmunopatogénesis, y estrategias terapéuticas para pacientes con Mielitis transversa. El conocimiento actual sobre la clasificación, diagnóstico, patogénesis y tratamiento de la Mielitis Transversa, ha sufrido recientemente cambios y nuevos aportes, especialmente con el desarrollo de la neuroinmunopatología. Actualmente podemos iniciar tratamientos oportunos para muchos de éstos pacientes, y mejorar el pronóstico a largo plazo de ésta rara, pero discapacitante noxa.
Subject(s)
Humans , Female , Adult , Lupus Erythematosus, Systemic , Lupus Erythematosus, Systemic/complications , Myelitis, Transverse/complications , Myelitis, Transverse/etiologyABSTRACT
The spike glycoprotein of infectious bronchitis virus (IBV), a coronavirus, is translated as a precursor protein (So), then cleaved into two subunits (S1 and S2) by host cell serine proteases. In this study, we compared the cleavage recognition site of 55 IBV isolates to determine if the cleavage recognition site sequence, which consists of five basic amino acid residues, correlates with host cell range, serotype, geographic origin, and pathogenicity as it does in orthomyxoviruses and paramyxoviruses. The most common cleavage recognition site observed (33 of 55 viruses) was Arg-Arg-Ser-Arg-Arg, representing at least 11 different serotypes. Thus, cleavage recognition site does not appear to correlate with serotype. We also determined that cleavage recognition site sequence does not correlate with pathogenicity because attenuated and pathogenic isolates (different passages of the same virus) contain identical cleavage recognition site sequences. In addition, nephropathogenic strains had the same cleavage recognition site sequence as many nonnephropathogenic isolates. Cleavage recognition site sequence does correlate with viruses in different geographic regions, which may be an important characteristic to examine in epidemiologic studies. An IBV monoclonal antibody neutralization-resistant mutant (NR 18) had an unusual substitution of Ile for Arg at the fourth position, giving the sequence Arg-Arg-Ser-Ile-Arg, which likely prevents cleavage and, thus, destroys the conformationally dependent monoclonal antibody binding epitope. Six residues on the amino-terminal side of the cleavage recognition site are conserved in 31% of the isolates and consist of only one or two basic amino acids. Thus, the number of basic residues around the cleavage recognition site does not appear to correlate with increased cleavability, host cell range, and increased virulence as it does with envelope glycoproteins in orthomyxoviruses and paramyxoviruses.
Subject(s)
Infectious bronchitis virus/genetics , Membrane Glycoproteins/genetics , Viral Envelope Proteins/genetics , Amino Acid Sequence , Animals , Antibodies, Monoclonal/immunology , Base Sequence , Infectious bronchitis virus/classification , Infectious bronchitis virus/immunology , Membrane Glycoproteins/chemistry , Membrane Glycoproteins/metabolism , Molecular Sequence Data , Phylogeny , Reverse Transcriptase Polymerase Chain Reaction/veterinary , Sequence Analysis/veterinary , Serine Endopeptidases/metabolism , Serotyping/veterinary , Spike Glycoprotein, Coronavirus , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/metabolismABSTRACT
We have isolated outer and inner membranes of Serpulina hyodysenteriae by using discontinuous sucrose density gradients. The outer and inner membrane fractions contained less than 1 and 2%, respectively, of the total NADH oxidase activity (soluble marker) in the cell lysate. Various membrane markers including lipooligosaccharide (LOS), the 16-kDa outer membrane lipoprotein (SmpA), and the C subunit of the F1F0 ATPase indicated that the lowest-density membrane fraction contained outer membranes while the high-density membrane fraction contained inner membranes and that both are essentially free of contamination by the periplasmic flagella, a major contaminant of membranes isolated by other techniques. The outer membrane fractions (rho = 1.10 g/cm3) contained 0.25 mg of protein/mg (dry weight), while the inner membrane samples (rho = 1.16 g/cm3) contained significantly more protein (0.55 mg of protein/mg [dry weight]). Lipid analysis revealed that the purified outer membranes contained cholesterol as a major component of the membrane lipids. Treatment of intact S. hyodysenteriae with different concentrations of digitonin, a steroid glycoside that interacts with cholesterol, indicated that the outer membrane could be selectively removed at concentrations as low as 0.125%.
Subject(s)
Brachyspira hyodysenteriae/chemistry , Cell Membrane/chemistry , Cholesterol/analysis , Lipoproteins , Bacterial Outer Membrane Proteins/analysis , Bacterial Proteins/analysis , Digitonin/pharmacology , Flagellin/analysis , Indicators and Reagents/pharmacology , Lipopolysaccharides/analysis , Membrane Lipids/analysis , Proton-Translocating ATPases/analysisABSTRACT
El autor hace una reseña bibliográfica en el contexto histórico de Claudio Galeno (131-201 D.C), resaltando su aporte a la otorrinolaringología y su proyección futura en la medician, perdurando sus enseñanzas y escritos por más de 1300 años, es decir, hasta el renacimiento.
