Normal development of fetal hepatic haematopoiesis during the second trimester of gestation is upregulated by fibronectin expression in the stromal cells of the portal triads. Tamiolakis, I. Venizelos 1 , S. Nikolaidou and T. Jivanakis 1. Department of Cytology.
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Erythropoiesis and Erythrophagocytosis in Bovine Haemal Nodes. Facultad de Ciencias Veterinarias. Universidad Nacional de Rosario. Facultad de Veterinaria. Universidad de Santiago de Compostela. The structure, fine structure and blood supply of haemal nodes are currently uncontroversial. In particular, current anatomical knowledge provides a basis for distinguishing between haemolymph nodes, which are endowed only with blood vessels however, since this distinction is not made by all the authors cited in this paper, in what follows, we refer to other author's work using the term employed by those authors, and otherwise use the term "haemal" throughout.
Few authors have in fact suggested that erythropoiesis takes place in haemal nodes. Erencin reported that the haemolymph nodes of sheep and goats contain myeloid cells and erythroblast, and suggested that they act in the same way as bone marrow; and Salazar found bovine haemal lymph nodes to contain lymphoblast, myeloblats and erythroblast; but Folse et al.
Kitagawa et al. Lorvik et al. Al-Bagdadi et al. Their irregular perinuclear zones contained granular material of similar density to that of rough endoplasmic reticulum, and some showed morphological evidence of various phases of erythrophagocytosis, which had previously been observed only in pathological specimens.
The phagocyted erythrocytes appeared to be smaller than usual. Most plasmacytes had Russel bodies in the cisternae of their rough endoplasmic reticulum, and some of the Russel bodies showed fuzzy borders and were separated from the endoplasmic reticulum by a halo of uniform width. Finally, Ezeasor et al. Haemal node macrophages were similar to spleen macrophages in form and location, and exhibited similar lysosomal degradation of erythrocytes.
These authors concluded that the architecture and cell composition of haemal nodes are appropriate for remo val of erythrocytes from the circulation. In this situation, we are considered appropriated to make a histological study by using histological techniques applied by other authors, accompanied by more current detection's techniques.
In this manner, we could corroborate the results obtained by others, in relation with the existence of erythropoiesis and erythrophagocytosis in bovine haemal nodes, or not.
We are not considered necessary to achieve this objective to make any quantitative evaluation of the results. It may be a new aim's design and to lead to a new investigation work. Seventy five haemal nodes were obtained from fifteen healthy Canadian Friesian cattle, including calves, yearlings and adults, following slaughter at the Osear Mayer abattoir in Albacete, Spain.
From each animal, five haemal nodes were removed from the mesenteric and perirectal regions using a scalpel and tweezers. The proportions of material from the three age classes were maintained throughout subsequent processing.
Light microscopy. Haemal nodes were fixed by immersion for 24 h in 2. The occurrence of erythrophagocytosis in bovine haemal nodes was confirmed by the presence, in Prusian-blue-stained sections, of abundant haemosiderin in the haemal node sinuses and in the cytoplasm of some macrophages Fig. TEM showed macrophages and polymorphonuclear cells performing erythrophagocytosis in the sinuses, and others with erythrocyte debris in their cytoplasm Fig. In the collagenous capsule, Giemsa-stained sections showed elongated nuclei belonging to smooth muscle cells.
The sinuses also contained both neutrophilic and eosinophilic granulocytes. The lumina of the sinuses also contained cells in the process of enucleation identified as orthochromatophilic erythroblast metarubricytes. Cells positive for the erythroid-specific transmembrane protein glycophorin A were found in the haemal nodes examined by inrmunofluorescence microscopy and streptavidin-biotn-labelled anti-GYPA Fig. These cells were found in the subcapsular sinus, the perinodular region and the trabeculae of the sinuses Fig.
In short, these observations confirm the presence, in bovine haemal nodes, of cells in various stages of erythropoiesis. It is performed primarily by macrophages, mainly in the spleen but also in liver, lung, bone marrow and, in certain species, in haemal or haemolymph nodes Ezeasor; Lorvik et al. Although Folse et al , failed to detect erythrophagocytosis in bovine haemal nodes, they did observe variation in the arrangement and colour of erythrocytes located in the sinuses, which indicates age differences among these cells.
We observed large quantities of haemosiderin, the pigment produced by degradation of haemoglobin, in both the sinuses and the cytoplasm of some macrophages; and TEM images showed numerous macrophages and polymorphonuclear cells with erythrocyte debris in their cytoplasm or actually in the act of erythrophagocytosis.
In haemal nodes of goats, Ezeasor et al , reported observing erythrophagocytosis by endothelial cells, reticular cells, lymphocytes and eosinophils as well as by macrophages. Neither Ezeasor et al. The observation of erythroblast in haemolymph nodes was reported by Erencin and Salazar. In this study of bovine haemal nodes we observed red cells in several stages of erythropoiesis proerythroblats and basophilic, polychromatophilic and ortochromatophilic erythroblast , and also megakaryocytes.
That bovine haemal nodes perform erythropoiesis was denied by Folse et al , and Lorvik et al , who failed to observe erythrocyte precursors, although Folse et al , did observe megakaryocytes; while Kitagawa et al , observed erythropoiesis in only 1 of 86 haemolymph nodes taken from goats in which erythropoiesis had been activated experimentally, and concluded that reticulocytes observed in these nodes had infiltrated from the circulation. The difference between Kitagawa et al.
Al-Bagdadi, K. R; Seger, C. Anal Histol. Embryol , 15 4 , Embryol , , Hemolymph Nodes in Small Ruminants. Erythrophagocytosis in the Caprine Hemal Nodes. Acta Anat. Basel , 4 , C; Sarlesw, H. Characterization of the Bovine Hemal Node. Reticuloendothel Soc , , Sel , , I Nodi Ematici del Bovino. Archivo veterinario italiano , Cytobiologie , 2 3 , The use of lead citrate at high pH as an electron opaque stain in electron microscopy.
Cell Biol , , Medicina Veterinaria , 1 10 , Anal , 1 , Correspondence to:. Servicios Personalizados Revista. Casilla D Temuco - Chile Tel.
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Fetal Erythropoiesis in Stress Hematopoiesis
Erythropoiesis and Erythrophagocytosis in Bovine Haemal Nodes. Facultad de Ciencias Veterinarias. Universidad Nacional de Rosario. Facultad de Veterinaria.
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Erythropoiesis
Fetal erythropoiesis occurs during chronic bone marrow failure, or during recovery from marrow suppression. Many of these fetal characteristics are present in the red cells of patients with temporary or chronic hematopoietic stress. In those in whom normal hematopoiesis ensues, the fetal erythrocytes disappear. The fetal phase of recovery may be with homologous stem cells after bone marrow engraftment, or with autologous cells.
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Hidrops fetal no inmune por anemia diseritropoyética congénita
Erythropoiesis from Greek 'erythro' meaning "red" and 'poiesis' meaning "to make" is the process which produces red blood cells erythrocytes , which is the development from erythropoietic stem cell to mature red blood cell. It is stimulated by decreased O 2 in circulation, which is detected by the kidneys , which then secrete the hormone erythropoietin. By the third or fourth month, erythropoiesis moves to the liver. Increased level of physical activity can cause an increase in erythropoiesis. This is termed extramedullary erythropoiesis.
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