ABSTRACT
La adenosin deaminasa (ADA), es una enzima del metabolismo de las purinas que ha sido objeto de mucho interés debido a que el defecto congénito de esta enzima causa el síndrome de inmunodeficiencia combinada severa. Una de las tres isoformas de la enzima (ecto-ADA) es capaz de unirse a la glicoproteína CD26 y a los receptores de adenosina A1 y A2B. La interacción ADA-CD26 produce una señal coestimuladora en los eventos de activación de las células T y en la secreción de IFN-g, TNF-a e IL-6. Durante dicha activación la actividad de la enzima está regulada de manera positiva por IL-2 e IL-12 y negativamente por IL-4, basado en un mecanismo de translocación. Diversos estudios señalan que los niveles séricos y plasmáticos de ADA se elevan en algunas enfermedades causadas por microorganismos que infectan principalmente a los macrófagos; así como en trastornos hipertensivos, lo cual podría representar un mecanismo compensatorio como consecuencia de la elevación de los niveles de adenosina y la liberación de mediadores hormonales e inflamatorios estimulados por la hipoxia.
Adenosine deaminase (ADA) is an enzyme of purine metabolism which has been the subject of much interest because the congenital defect of this enzyme causes severe combined immunodeficiency syndrome. One of the three isoforms of the enzyme (ecto-ADA) is capable of binding to the glycoprotein CD26 and adenosine receptors A1 and A2B. ADA-CD26 interaction produces a costimulatory signal in the events of T cell activation and secretion of IFN-g, TNF-a and IL-6. During this activation, the enzyme activity is regulated positively by IL-2 and IL-12 and negatively by IL-4, based on the mechanism of translocation. Diverse studies suggest that seric and plasmatic levels of ADA rise in some diseases caused by microorganisms infecting mainly the macrophages and in hypertensive disorders, which may represent a compensatory mechanism resulting from increased adenosine levels and the release of hormones and inflammatory mediators estimulated by hipoxia.
Subject(s)
Female , Humans , Pregnancy , Adenosine Deaminase/physiology , Immunity, Cellular , Adenosine Deaminase/blood , Adenosine Deaminase/deficiency , Adenosine Deaminase/genetics , Adenosine Deaminase/immunology , Adenosine/physiology , Agammaglobulinemia/genetics , Agammaglobulinemia/immunology , Cell Hypoxia , Communicable Diseases/enzymology , Communicable Diseases/immunology , Dendritic Cells/enzymology , Dendritic Cells/immunology , /physiology , Enzyme Induction , Hepatitis, Viral, Human/enzymology , Hepatitis, Viral, Human/immunology , Hypertension, Pregnancy-Induced/enzymology , Hypertension, Pregnancy-Induced/physiopathology , Immunological Synapses , Inflammation Mediators/metabolism , Interferon-gamma , Interleukins , Isoenzymes/physiology , Lymphocyte Activation , Receptors, Purinergic P1/physiology , Severe Combined Immunodeficiency/genetics , Severe Combined Immunodeficiency/immunology , T-Lymphocytes/immunology , T-Lymphocytes , Tumor Necrosis Factor-alphaABSTRACT
The presence of aminoglycoside modifying enzyme (AMEs) has been investigated by an agar diffusion method, in 344 strains of aminoglycoside-resistant Gram negative bacilli isolated in different Chilean hospitals. Most of the strains exhibited a combination of enzymatic mechanism of resistance, but 2 acetylatting (AAC(3)II and AAC(6')I) and one phosphorylating (APH(3')I) enzymes were mechanism detected in the strains. A significant increase in the frequency of strains producing AAC(6')I), possibly due to wide use of amikacin, has been found when results were compared with those of a report published in 1985