oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 556 )

2018 ( 874 )

2017 ( 805 )

2016 ( 1168 )

Custom range...

Search Results: 1 - 10 of 503070 matches for " Carlos A. Ca as "
All listed articles are free for downloading (OA Articles)
Page 1 /503070
Display every page Item
The Biological Significance of Evolution in Autoimmune Phenomena
Carlos A. Ca?as,Felipe Ca?as
Autoimmune Diseases , 2012, DOI: 10.1155/2012/784315
Abstract: It is an inherent part of living to be in constant modification, which are due to answers resulting from environmental changes. The different systems make adaptations based on natural selection. With respect to the immune system of mammals, these changes have a lot to do with the interactions that occur continuously with other living species, especially microorganisms. The immune system is primarily designed to defend from germs and this response triggers inflammatory reactions which must be regulated in order not to generate damage to healthy tissue. The regulatory processes were added over time to prevent such damage. Through evolution the species have stored “an immunological experience,” which provides information that is important for developing effective responses in the future. The human species, which is at a high level of evolutionary immunological accumulation, have multiple immune defense strategies which, in turn, are highly regulated. Imbalances in these can result in autoimmunity. “There is nothing permanent except change.” (Heraclitus) 1. Introduction Life began on earth more than 3.5 billion years ago and evolution has allowed the development of myriads of species from very simple to highly complex ones. Initially, unicellular microorganisms without a nucleus (prokaryotes) similar to modern bacteria appeared and after that others with a nucleus similar to amoebas. These ancestral amoebas developed in groups and have been called “social amoebas.” These feed on bacteria in the soil and they aggregate when there is a serious lack of food to form a migrating group. A type of amoeba in these groups differentiated and facilitated the process of detoxification through immunological mechanisms and became what is called a sentinel (S-cell) [1]. The S-cell engulfs bacteria and sequesters toxins. This may be the origin of the immune system. Subsequently, these unicellular eukaryotes differentiated into diverse functions and developed forms of signaling and adhesion molecules which allowed them to aggregate. This could have been the beginning of evolution of multicellular organisms (metazoans) which later migrated from the sea [2]. Around 600 million years ago, terrestrial metazoans began to develop in conjunction with an important increase in the oxygen concentration in the atmosphere. The vertebrate animals with their remarkable diversification appeared 500 million years ago in a relatively short time period termed the “evolutionary big bang.” Since the beginning of life, the most important element of evolution has been the increasing ability of
Local Cartilage Trauma as a Pathogenic Factor in Autoimmunity (One Hypothesis Based on Patients with Relapsing Polychondritis Triggered by Cartilage Trauma)
Carlos A. Ca?as,Fabio Bonilla Abadía
Autoimmune Diseases , 2012, DOI: 10.1155/2012/453698
Abstract: In the recent years, it has been of great interest to study the binding mechanism between the innate and adaptive immune responses as interrelated processes for the development of multiple autoimmune diseases. Infection has been a well-known trigger of autoimmunity and trauma has been related as well too. Cryptogenic antigens release, recognition of pathogenic structure, and metabolic changes generated by both stimuli begin an inflammatory process which in turn activates the immune system amplifying T and B cell responses. The development of relapsing polychondritis after trauma may have a direct association with these events and in turn probably trigger autoimmune phenomena. 1. Introduction Proteins that are hidden in the tissues and by different events such as trauma begin to be recognized and attacked by immune system are called cryptogenic antigens, so it starts a process initially with innate and later with acquired immunity mechanisms. An example of this condition is the sympathetic ophthalmia (SO) where breaching of systemic ocular barriers compromises the relative immune privilege of the eye and causes sensitization to previously sequestered uveoretinal antigens [1]. A similar mechanism is observed in relapsing polychondritis (RP) started by local cartilage trauma triggering an immune response against cartilage in distant sites of the body and even in noncartilaginous tissues [2]. 2. Lessons Learned of SO This disease is precipitated by ocular trauma to one eye, followed by destructive inflammation in the nontraumatized or “sympathizing” eye [3]. It is thought that antigens released from the traumatized eye find their way into the draining lymph node and generate systemic immune response [4]. An accompanying infection may provide an adjuvant effect, although severe endophthalmitis, which quickly destroys the injured eye and eliminates the source of antigen, may actually lessen chances of developing the disease [5]. In uveitic disease, it is believed that T cells are capable of recognizing retinal antigens by microbial stimuli that may be immunologically similar in structure to their cognate retinal antigen (antigenic mimicry). Microbial components also interact with innate pattern recognitionreceptors (PRRs) on antigen-presenting cells, generating “danger” signals that are necessary to elicit inflammatory reactions. Following exposure to an uveitogenic stimulus, circulating retinal antigen-specific cells become activated and acquire effectors function [5]. In the above examples, it is postulated that the retinal antigen recognition distance may
Veredas: revista del pensamiento sociológico " Trabajo colectivo e identidad académica "
José Antonio Rosique Ca?as,Carlos García Villanueva
Reencuentro , 2005,
Abstract: Primero se presenta una visión general de los orígenes del pensamiento sociológico en Europa, su llegada a México, la recepción por parte de los círculos intelectuales y gubernamentales: rechazos, aceptaciones y adaptaciones, y su institucionalización como ciencia y como carrera en términos de investigación, publicaciones y escuelas. Después, se describe la fundación de Veredas como revista del pensamiento sociológico, su política editorial ligada a su comunidad educativa y de investigación, sus procedimientos de selección de colaboraciones, dictaminación y preparación de los trabajos, así como los vínculos entre su Departamento y la División de Ciencias Sociales y Humanidades para la producción editorial, difusión y posterior distribución y venta a través de la Biblioteca y Librería de la UAM-Xochimilco y el resto del entorno interinstitucional.
B Lymphocytes: Development, Tolerance, and Their Role in Autoimmunity—Focus on Systemic Lupus Erythematosus
Gabriel J. Tobón,Jorge H. Izquierdo,Carlos A. Ca?as
Autoimmune Diseases , 2013, DOI: 10.1155/2013/827254
Abstract: B lymphocytes are the effectors of humoral immunity, providing defense against pathogens through different functions including antibody production. B cells constitute approximately 15% of peripheral blood leukocytes and arise from hemopoietic stem cells in the bone marrow. It is here that their antigen receptors (surface immunoglobulin) are assembled. In the context of autoimmune diseases defined by B and/or T cell autoreactive that upon activation lead to chronic tissue inflammation and often irreversible structural and functional damage, B lymphocytes play an essential role by not only producing autoantibodies but also functioning as antigen-presenting cells (APC) and as a source of cytokines. In this paper, we describe B lymphocyte functions in autoimmunity and autoimmune diseases with a special focus on their abnormalities in systemic lupus erythematosus. 1. Introduction Systemic lupus erythematosus (SLE) is the prototype of the systemic autoimmune diseases characterized by multiorgan involvement. This systemic compromise is mediated by a global loss of self-tolerance. The loss of tolerance is a consequence of genetic factors, in the context of specific environmental triggers, with the subsequent development of an altered immune response. Both innate and acquired immune mechanisms are implicated in the disease pathogenesis. Recently, special attention has been focused on the B cell abnormalities. In this paper, we will describe the B cell development, tolerance mechanism, and their implications in autoimmune diseases, with emphasis on SLE. 2. B Cell Development and the B Cell Receptor Formation Different populations of B cells result in preimmune pools where each cell in these quiescent populations expresses a B cell antigen receptor (BCR) with a unique specificity. When the BCRs come in contact with their specific antigen, several intracellular signals are generated leading to activation, differentiation, and formation of plasma cells and memory B cells. This last subset of B cells maintains protective antibody levels and mediates the response to subsequent antigen challenges. As the mechanisms leading to maturing and antibody production are complex, the alterations of some of these populations or critical steps have been associated with immunodeficiency and autoimmune diseases. Table 1 summarizes the most important features of each of the subpopulations (lineages) of B lymphocytes [1]. Table 1: Characteristics of primary B cell subsets and their progenitors. 2.1. B Cell Development This process begins from stem cells present in the bone marrow
Efficacy and Safety of Rituximab in the Treatment of Vasculitic Leg Ulcers Associated with Hepatitis C Virus Infection
Fabio Bonilla-Abadía,Andrés F. Echeverri,Jorge H. Izquierdo,Felipe Ca?as,Carlos A. Ca?as
Case Reports in Rheumatology , 2012, DOI: 10.1155/2012/923897
Abstract: Vasculitic leg ulcers are a cutaneous manifestation of hepatitis C virus (HCV) infection often associated with cryoglobulinemia. Their treatment is difficult and is based on steroids and immunosuppressive drugs with an erratic response and a high probability of adverse reaction. We report three patients with vasculitic leg ulcers associated with hepatitis C virus infection who were treated successfully with rituximab. The pain control and healing were achieved quickly. No adverse effects with rituximab in these patients were presented. 1. Introduction Infection with hepatitis C virus (HCV) causes chronic liver disease in approximately 80% of cases, resulting in chronic inflammation and cirrhosis [1]. It is frequently associated with autoimmune extrahepatic complications including systemic vasculitis [2]. Its degree of compromise is variable, ranging from mild to fulminant often affecting nerves and kidney. Immune complex mediated is the most common form of vasculitis in HCV infection, which involves the small vessels (venules, capillaries, and arterioles) and is associated or not to cryoglobulinemia [3]. Skin is one of the most frequently affected organs [4]. Clinical characteristics comprise palpable purpura and very painful leg ulcers. These ulcers tend to be chronic and difficult to treat with a significant impact on psychosocial aspects as well as on physical well-being [5]. Bearing in mind recent reports of the effectiveness and safety of rituximab in cases of cryoglobulinemic vasculitis associated with HCV infection [6], we decided to treat three patients with vasculitis leg ulcers associated to chronic HCV infection refractory to steroids and with contraindications to receive cytotoxic treatment. The patients achieved a rapid control of pain and scarring. 2. Methods Between August 2001 and September 2010, we treated 16 patients with autoimmune phenomena triggered by HCV infection in a tertiary health care center in Cali, Colombia. Three patients with steroids refractory vasculitic leg ulcers were treated with rituximab. 2.1. Case 1 A 73-year-old woman was admitted because painless ulcers on the lower limbs which appeared six months earlier. Her past medical history was remarkable for a long-lasting progressive demyelinating disease of spinal cord. On examination, extensive palpable purpura and ulcers on the lower limbs were observed. Her cardiopulmonary examination was normal. Alteration of proprioception and ataxia were evidenced. Laboratory exams showed elevated sedimentation rate 58?mm/h, C3 54.7?mg/dL (90–180), C4 11.8?mg/dL (10–40), and a
Possible Influence of Resistance to Malaria in Clinical Presentation of Rheumatoid Arthritis: Biological Significance of Natural Selection
Fabio Bonilla-Abadía,Gabriel J. Tobón,Carlos A. Ca as
Arthritis , 2012, DOI: 10.1155/2012/670579
Abstract: Rheumatoid arthritis (RA) is a common autoimmune disease that affects all ethnic groups. Genetic factors, mainly HLA alleles, are highly associated with increased risk to develop RA. However, there are few available data about the role of these genetic polymorphisms in the prevalence or severity of RA in the Afrodescendant population, who have evolutionarily and by natural selection developed mutations that allowed them to acquire resistance to infectious diseases like malaria. Some of the mechanisms, by which this resistance was developed as a product of natural selection, are involved in different forms of immunological response, many of them of a well-known importance in the pathophysiology of RA. This paper focuses on presenting the known mechanisms of resistance to malaria and their possible contribution to the pathophysiology of RA, including “loss-of-function” mutations, lack of expression of chemokine receptors, decrease of immune complexes clearance by asplenia, or increase of immune reactivity mediated by B cells, among other mechanisms in this special group of patients.
Successful Treatment of Hemifacial Myokymia and Dystonia Associated to Linear Scleroderma “En Coup de Sabre” with Repeated Botox Injections
Carlos A. Ca as,Jorge L. Orozco,Andrea Caicedo Paredes,Fabio Bonilla-Abadía
Case Reports in Medicine , 2012, DOI: 10.1155/2012/691314
Abstract: Linear scleroderma “en coup de sabre” (LSCS) is a form of localized scleroderma presents as band-like sclerotic lesions of the frontoparietal area. It has been reported in association with diverse neurological manifestations like seizures, migraine, neuromyotonia, dystonia and abnormalities in MRI and CT studies as cerebral atrophy, white matter lesions, intraparenchymal calcification, meningeocortical alterations, and skull atrophy. We describe a patient with LSCS associated with two abnormal movements: permanent myokimia of right masseter muscle and recurrent spasmodic retraction of right cigomatic and depressor labii inferioris muscles. He was initially treated with methotrexate and steroids without response, so later on he underwent repeated Botox injections with remarkable improvement.
Paracoccidioidomicosis diseminada asociada a hipercalcemia y síndrome hemofagocítico
Navarro,Ana María; Pérez,Paola; Arrunategui,Ana María; Ca?as,Carlos Alberto;
Acta Medica Colombiana , 2008,
Abstract: this case report describes a 12 year old male patient with disseminated paracoccidioides brasiliens disease. the patient presented with a febrile syndrome of long duration, weight loss, hepato-splenomegaly, cervical adenomegalies, and bone involvement. additional components attesting to the severity of the disease process were macrophage activation, hypercalcemia and hemophagocytosis.
Evaluación de Esteroides Aromáticos como Indicadores de Madurez Térmica en Extractos de Roca
Ca?ipa,Nora K; Aldana,Claudia R; Zú?iga,Claudia A; Galán,Carlos A;
Información tecnológica , 2009, DOI: 10.4067/S0718-07642009000200009
Abstract: in this work the application of monoaromatic (ma) and triaromatic (ta) steroids analyzed by gas chromatography/mass spectrometry as thermal maturity indicators in rock extracts is evaluated. a set of 26 rock extracts that varies from immature to highly mature was used. the evaluated parameter ta/(ma+ta) can be use to characterize the migration pathway of highly thermal maturity samples while most of the conventional geochemical parameters have limitations in their applications. this because they reach a constant value at high maturity levels and they do not contribute any additional information to define the migration pathways.
Paracoccidioidomicosis diseminada asociada a hipercalcemia y síndrome hemofagocítico Disseminated paracoccidioidomycosis associated with hypercalcemia and hemophagocytic syndrome
Ana María Navarro,Paola Pérez,Ana María Arrunategui,Carlos Alberto Ca?as
Acta Medica Colombiana , 2008,
Abstract: Se informa el caso de un paciente de sexo masculino y de 12 a os de edad con infección diseminada por Paracoccidioides brasiliens. El paciente se presenta con un síndrome febril prolongado, pérdida de peso, hepatoesplenomegalia, adenomegalias cervicales y compromiso en los huesos y articulaciones de la cintura escapular. Como componentes de la severidad del cuadro clínico y la activación de macrófagos, se encontró hipercalcemia y fenómeno hemofagocítico. This case report describes a 12 year old male patient with disseminated Paracoccidioides brasiliens disease. The patient presented with a febrile syndrome of long duration, weight loss, hepato-splenomegaly, cervical adenomegalies, and bone involvement. Additional components attesting to the severity of the disease process were macrophage activation, hypercalcemia and hemophagocytosis.
Page 1 /503070
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.