Anatomía Comparada del Bazo de la Rata Blanca (Rattus norvegicus albinus), Una Revisión de la Literatura / Comparative Anatomy of the Spleen of the White Rat, (Rattus norvegicus albinus) a Literature Review

El bazo es el órgano linfático intraperitoneal más grande del organismo, presentando dos funciones principales: defensiva, mediante respuesta inmunitaria y filtración sanguínea. El objetivo de la presente revisión, fue obtener información actualizada sobre la anatomía del bazo de la rata albina (Rattus norvegicus albinus) y comparativa con la anatomía del bazo humano, perro, gato y cerdo, al representar las principales especies de importancia en la medicina, medicina veterinaria y en las ciencias biomédicas. Se realizó una búsqueda de material bibliográfico actualizado en diferentes sitios web científicos. Es así como, se revisaron 71 fuentes bibliográficas, en su gran mayoría artículos científicos (31), libros de anatomía humana y veterinaria (17), artículos especializados (17) y tesis (6). En general existe consenso, sobre la descripción anatómica del bazo, el cual se sitúa en la región hipocondriaca izquierda del abdomen, entre el fondo del estómago y el diafragma, irrigado por la arteria y vena esplénica. Se evidenció que existen similitudes en aspectos macroscópicos, al comparar el bazo de la rata blanca, con el bazo de otras especies (funcionalidad, peso relativo, ubicación topográfica). En aspectos microscópicos, el bazo en humanos y otros mamíferos se compone de estroma, además de parénquima, constituido a su vez por pulpa blanca y roja. En particular, existen diferencias entre el bazo de rata, humano, gato, perro y cerdo, en formas, tamaños y aspectos microscópicos, relacionados con la microcirculación e inmunidad. Mientras que existen semejanzas en procesos patológicos y respuestas a tratamientos farmacológicos y clínicos. Por lo anteriormente expuesto, se concluye que la rata albina constituye un buen modelo biológico, específicamente en aspectos anatómicos microscópicos del bazo de tipo inmunológico. Mientras que el bazo de cerdo es mejor comparativamente, en estudios anatómicos macroscópicos de tipo quirúrgicos, resultando ambos extrapolables, especialmente a la medicina humana.

SUMMARY: The spleen is the largest intraperitoneal lymphatic organ of the body, presenting two main functions: defensive, through immune response and blood filtration. The objective of the present review was to obtain updated information on the anatomy of the spleen of the albino rat (Rattus norvegicus albinus) and to compare it with the anatomy of the human, dog, cat and pig spleen, representing the main species of importance in medicine, veterinary medicine and biomedical sciences. A search for updated bibliographic material was carried out in different scientific websites. Thus, 71 bibliographic sources were reviewed, mostly scientific articles (31), human and veterinary anatomy books (17), specialized articles (17) and theses (6). In general, there is consensus on the anatomical description of the spleen, which is located in the left hypochondriac region of the abdomen between the fundus of the stomach and the diaphragm, irrigated by the splenic artery and vein. It was evidenced that there are similarities in macroscopic aspects when comparing the spleen of the white rat with the spleen of other species (functionality, relative weight, topographic location). In microscopic aspects, the spleen in humans and other mammals is composed of stroma, in addition to parenchyma, constituted in turn by white and red pulp. In particular, there are differences between rat, human, cat, dog and pig spleens in shapes, sizes and microscopic aspects related to microcirculation and immunity. While there are similarities in pathological processes and responses to pharmacological and clinical treatments. For the above mentioned, it is concluded that the albino rat constitutes a good biological model, specifically in microscopic anatomical aspects of the spleen of immunological type. While the pig spleen is comparatively better in macroscopic anatomical studies of surgical type, both are extrapolable especially to human medicine.

The morphological basis of the development of the chick embryo immune system.

The chick immune system is a fundamental model in basic immunology. In birds, the bone marrow derived pluripotent stem cells after entering the circulation, migrate to bursa of Fabricius to benefit from a microenvironment which supports the differentiation and maturation of B lymphocytes by the help of its resident cells and tissues. Delivering sufficient functional B cells is required to maintain their peripheral population and normal peripheral humoral responses. Additionally, bursa acts as an active site for the generation of antibody diversity through gene conversion. Being consisted of 98% B lymphocytes, the organ is occupied by other cell types including T cells, macrophages, eosinophils and mast cells. Thymus, which is an epithelial organ is the main site of T cell development where positive and negative selections contribute to the development of functional and not autoreactive T cell repertoire. Bursectomy and thymectomy are surgical exercises through which the involvement of cells of specific immunity including B cells and T cells can be determined.

The Immune System Computes the State of the Body: Crowd Wisdom, Machine Learning, and Immune Cell Reference Repertoires Help Manage Inflammation.

Here, we outline an overview of the mammalian immune system that updates and extends the classical clonal selection paradigm. Rather than focusing on strict self-not-self discrimination, we propose that the system orchestrates variable inflammatory responses that maintain the body and its symbiosis with the microbiome while eliminating the threat from pathogenic infectious agents and from tumors. The paper makes four points: The immune system classifies healthy and pathologic states of the body-including both self and foreign elements-by deploying individual lymphocytes as cellular computing machines; immune cells transform input signals from the body into an output of specific immune reactions.Rather than independent clonal responses, groups of individually activated immune-system cells co-react in lymphoid organs to make collective decisions through a type of self-organizing swarm intelligence or crowd wisdom.Collective choices by swarms of immune cells, like those of schools of fish, are modified by relatively small numbers of individual regulators responding to shifting conditions-such collective inflammatory responses are dynamically responsive.Self-reactive autoantibody and T-cell receptor (TCR) repertoires shared by healthy individuals function in a biological version of experience-based supervised machine learning. Immune system decisions are primed by formative experience with training sets of self-antigens encountered during lymphocyte development; these initially trained T cell and B cell repertoires form a Wellness Profile that then guides immune responses to test sets of antigens encountered later. This experience-based machine learning strategy is analogous to that deployed by supervised machine-learning algorithms. We propose experiments to test these ideas. This overview of the immune system bears clinical implications for monitoring wellness and for treating autoimmune disease, cancer, and allograft reactions.

Histological and ultrastructural examinations of porcine tonsils.

The histology and ultrastructure of porcine tonsils were studied. The porcine tonsils were lymphoepithelial organs situated at the opening of both the digestive and respiratory tracts. The tonsil of the soft palate in the oropharyngeal tract and the paraepiglottic tonsil in the laryngopharynx were mainly consisted of secondary lymphoid follicles encapsulated by connective tissue. The stratified squamous epithelia covering the tonsils and their crypts were frequently heavily infiltrated by lymphoid cells. The pharyngeal and tubal tonsils (TT) were situated in the nasopharyngeal tract. The cells of the pseudostratified columnar epithelia of the pharyngeal and TT were loosely connected, with large intercellular space. They consisted of scattered lymphoid follicles, aggregations of lymphoid cells and diffuse lymphoid tissues. Many high endothelial venules, specialized for the diapedesis of lymphoid cells into the tonsillar tissue, were detected in the four porcine tonsils. Therefore, the overall structures of the tonsils (the tonsil of the soft palate, the paraepiglottic tonsil, the pharyngeal and the TT) reflect their immune functionality in the oral and intranasal immunity.

Anatomical particularities of the porcine immune system--a physician's view.

In this article the anatomical structure of the porcine immune organs is described. The focus is on their particularities that are related to the use of pigs as an animal model. Key issues of the intrauterine development of the lymphoid organs are presented, such as the specific epithelio-chorial placenta, the appearance of the thymic tissue and the initial development of B cells. The role of the thymus for the development of alpha/beta and gamma/delta T cells and the location of tonsillar tissue in the naso-pharynx, in the oral cavity and at the basis of the tongue are described. The porcine spleen is of interest for surgical techniques to treat splenic trauma adequately. The observation of the inverted lymph node structure of pigs is puzzling and it remains unclear why only few species have this distinct morphological organisation. Based on the functional differences in lymphocyte recirculation observed in pigs, specific lymph cannulation experiments are possible in the porcine immune system. The porcine intestinal lymphoid tissue and the lymphocytes in the mucosal epithelium and lamina propria are of interest for studying the gut immune responses. For use as a model the fact that the pig is a monogastric omnivorous animal represents an advantage, although the porcine ileal Peyer's patch has no obvious anatomical equivalent in man. Based on the detailed knowledge of porcine immune morphology the pig is suitable as model animal for immunology--in addition to the various experimental approaches in physiology, pharmacology, surgery, etc. that are applicable to human medicine.

Structure of immune organ in edible catfish, Mystus gulio.

The light microscopic study describes the anatomy and histomorphology of head-kidney in bagrid catfish, Mystus gulio. Showing numerous lymphocytes, interrenal cells, reticular cells, postcardinal vein, blood sinuses and melanomacrophage centers.

In vivo mature immunological synapses forming SMACs mediate clearance of virally infected astrocytes from the brain.

The microanatomy of immune clearance of infected brain cells remains poorly understood. Immunological synapses are essential anatomical structures that channel information exchanges between T cell-antigen-presenting cells (APC) during the priming and effector phases of T cells' function, and during natural killer-target cell interactions. The hallmark of immunological synapses established by T cells is the formation of the supramolecular activation clusters (SMACs), in which adhesion molecules such as leukocyte function-associated antigen 1 segregate to the peripheral domain of the immunological synapse (p-SMAC), which surrounds the T cell receptor-rich or central SMAC (c-SMAC). The inability so far to detect SMAC formation in vivo has cast doubts on its functional relevance. Herein, we demonstrate that the in vivo formation of SMAC at immunological synapses between effector CD8+ T cells and target cells precedes and mediates clearance of virally infected brain astrocytes.

Células y órganos del sistema inmune / Cells and organs of the immune system

Las células del sistema inmune que incluyen linfocitos, granulocitos y monocitos-macrófagos, se forman en la médula ósea a partir de células pluripotentes, a través de un proceso finamente regulado y el que participan varias citoquinas. Los granulocitos (neutrófilos, eosinófilos y basófilos) presentan particularidades morfológicas y funcionales. La principal función de los neutrófilos es su capacidad fagocítica. En el capítulo se explican los procesos de activación, quimiotaxis, fagocitosis y bacteriolisis. Las células del sistema fagocítico mononuclear (monocitos y macrófagos) tienen como función fagocitar; actividad más desarrollada en los macrófagos, que son células tisulares derivadas de los monocitos circulantes. Los linfocitos son las células que participan en la inmunidad adquirida o específica. Las células T participan en la inmunidad celular y las células B en la inmunidad humoral. Una tercera subpoblación de linfocitos, las células NK, participan en la inmunidad celular de tipo innata. Los órganos linfoides se pueden clasificar en primarios (timo y médula ósea) y secundarios (bazo, ganglios linfáticos y tejido linfoide asociado a mucosas). En el timo maduran los LT y en la médula ósea los LB. En los órganos linfoides secundarios los linfocitos y otras células del sistema inmune toman contacto con los antígenos y es en ellos donde se genera la respuesta inmune específica. En estos órganos existen zonas ricas en células T, y otras en que, principalmente, existen células B. La capacidad de los linfocitos de recircular entre los órganos linfoides secundarios, vasos linfáticos, conducto torácico y vasos sanguíneos le permiten tomar contacto con antígenos en diferentes lugares del organismo

Relaciones neuroquímicas entre el sistema nervioso y el sistema inmunológico (II) / Relate neurochemicals between the nervous system and the immunologic system (II)

Existen actualmente abundantes datos acerca de las relaciones neuroanatómicas, neuroendocrinas y neuroquímicas con el sistema inmune. No conocemos la naturaleza de todos los canales de comunicación entre el sistema nervioso y el sistema inmunológico o la significación funcional de las conexiones que han sido establecidas. Conocemos sin embargo que el sistema inmunológico es capaz de recibir señales neurales y neuroendocrinas

El sistema inmune / The immune system

Many are these aspects of immunology that can be approached; it is difficult to refer to all of then in particular, considering both the volume of information gathered and the availability of space. This review outstands and updates the basic aspects of normal immunology thath are considered to be important due to their implication in the clinic area and for a better understanding of the immunopathologic phenomenon that physicians should face in their daily practice. There is a description of the different anatomic components of the immunologic suystem-pluripotential cells, primary and secondary lymophoid organs-as well as their physiologic aspects: specific immune answer. Immunologic induction and tolerance phases are given in detail as well as the regulation of the immune answer to antigens