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Immune System Imaging
Published in Margarida M. Barroso, Xavier Intes, In Vivo, 2020
Michael J. Hickey, M. Ursula Norman
The spleen is surrounded by a fibrous capsule that extends protrusions (trabeculae) into the splenic tissue to provide support for its vast branching vasculature (Figure 18.4) (Mebius and Kraal, 2005). As a filter of the blood, it has a unique open circulation in that capillaries empty blood out into either the marginal sinus (the inner junction between the white pulp and the MZ), the MZ, or directly into the red pulp (Cesta, 2006). Blood freely moves through the stromal tissue of these areas and is recollected into specialized sinuses in the red pulp for venous drainage. The smallest artery branches (central arterioles) are surrounded by lymphoid tissue (white pulp) that is structurally organized into T cell (periarteriolar lymphoid sheath [PALS]) and B cell zones (B-cell follicles) (Figure 18.5), paralleling the layout found in lymph nodes. The MZ separating the white and red pulp represents an important transit area for the cells leaving the circulation. This zone contains specialized macrophages, DCs, and a resident population of B cells (MZ B cells) that have distinct features relative to B cells in splenic follicles. Access to the white pulp through the marginal zone is restricted to B cells, T cells, and DCs that are attracted to their respective zones by specific chemokines.
Evaluation of cytotoxic potential, oral toxicity, genotoxicity, and mutagenicity of organic extracts of Pityrocarpa moniliformis
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Tamiris Alves Rocha, Danielle Feijó de Moura, Marllyn Marques da Silva, Talita Giselly dos Santos Souza, Maria Aparecida da Conceição de Lira, Dayane de Melo Barros, Alexandre Gomes da Silva, Rafael Matos Ximenes, Emerson Peter da Silva Falcão, Cristiano Aparecido Chagas, Francisco Carlos Amanajás de Aguiar Júnior, Noêmia Pereira da Silva Santos, Marcia Vanusa da Silva, Maria Tereza dos Santos Correia
Decreases in the area of corpuscles and renal glomeruli were observed after treatment with extracts EP1 and EP2 (Figure 6) (Table 5), suggesting a deficiency in filtration rate, as the glomerulus is the initial site of exposure to chemical substances, which may promote modifications in its structure and function. In some situations, these substances may lead to altered permeability and proteins with modification in size and load; and therefore the development of lesions at this site (Klaassen 2007). There was a significant rise in the stroma in the group treated with EP3. Data presented in Table 6 also show that there was a significant decrease in white pulp in the group treated with EP1. It is of interest that white pulp houses T lymphocytes and hence the defenses of an organism reliant on the spleen may be compromised (Aguiar et al. 2008; Christopher 2003; Torres et al. 2000).
Histological analysis of the effects of cadmium, chromium and mercury alone and in combination on the spleen of male Sprague-Dawley rats
Published in Journal of Environmental Science and Health, Part A, 2020
Chantelle Venter, Anel Olivier, Helena Taute, Hester M. Oberholzer
The effects of Cd, Cr and Hg alone and in combination on the spleen tissue were examined by using light microscopy. During the general light microscopy analysis, the red- and white pulp regions of the tissue were chosen, as they are the regions in the spleen that play a major role in the immune function. Lymphocytes are present in the white pulp region and macrophages are present in the red pulp region.[10] Lymphocytes are a type of white blood cell that functions as part of the body’s immune system. There are three main types of lymphocytes: T-cells, B-cells and NK cells.[10] In the current study, no cellular alterations were observed surrounding the central artery (white pulp region) in the control group (Fig. 1B). The Cd (Fig. 1D) and Cr (Fig. 1F) individually exposed groups showed minimal and moderate necrosis of cells in the white pulp region. The Hg exposed group (Fig. 1H) revealed severe necrosis of cells in the white pulp region. In a similar study, Ilbäck in 1991[11] found that after exposure to Hg the NK cell numbers were depleted and thus supports the loss in cells that were found in the white pulp in this current study. All the combination groups revealed severe necrosis in the cells located in the white pulp region. In the Cd and Cr combination group (Fig. 2J) the severity of necrosis may be attributed to the fact that Cd, which causes minimal necrosis alone, and Cr, which causes moderate necrosis by itself, to have an additive effect when administered in combination. To our knowledge, no literature pertaining to the effects of simultaneous exposure to heavy metals on the spleen is available and therefore there were no comparison to previous literature in terms of the metal combination groups.