Reticuloendothelial System: The Basics

2018 ◽  
pp. 617-625
Author(s):  
Jenny X. Qian ◽  
Bradley B. Pua
Keyword(s):  
Reticuloendothelial System ◽  
Lymphoid Organ ◽  
Primary Site ◽  
Malignant Neoplasms ◽  
White Pulp ◽  
Vital Function ◽  
Abnormal Cells ◽  
Upper Abdomen

The spleen is the largest organ of the reticuloendothelial system and the largest lymphoid organ. Derived from embryologic mesoderm, it is a solid, intraperitoneal organ situated in the left upper abdomen, lateral and slightly posterior to the stomach. Long thought to be a superfluous structure, the spleen is now known to play a major role in immunity, as asplenic patients are predisposed to sepsis from encapsulated organisms. It is also an important reservoir for platelets, monocytes, and erythrocytes, and it performs the vital function of filtering the blood to remove senescent or abnormal cells, as well as circulating debris. Its ability to perform these functions is closely tied to the microarchitecture of both its red- and white-pulp components. In addition, the spleen plays an important role in the development of many diseases, and may be secondarily involved or, more rarely, the primary site of malignant neoplasms such as lymphoma.

scholarly journals Splenic Mechanisms of Thrombocytopenia

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-33-SCI-33
Author(s):  
John W. Semple
Keyword(s):  
Immune Responses ◽  
Reticuloendothelial System ◽  
Lymphoid Organ ◽  
The Body ◽  
White Pulp ◽  
Cellular Mechanisms ◽  
Venous Circulation ◽  
Destructive Processes ◽  
Clinical Conditions ◽  
Red Pulp

The spleen is the largest secondary lymphoid organ in the body and contains up to 25 percent of the body's lymphocyte populations. It is not only responsible for initiating immune responses against a multitude of infectious antigens within its white pulp, it also has the exquisite ability to filter the blood and remove, for example, senescent erythrocytes and platelets. This natural process is carried out within the red pulp of the spleen which is composed monocyte-rich connective tissue cords of Billroth intertwined with sinus cavities lined by parallel-oriented endothelial cells that have interendothelial slits which allow for the mechanical sorting of "old" cells. This occurs because of the inability of the senescent cells to properly migrate through the endothelial fenestrae into the venous circulation allowing them to be identified by cells of the reticuloendothelial system (RES) and quickly destroyed by phagocytosis. This process also allows for the efficient recycling of iron from destroyed erythrocyte hemoglobin molecules. There are a wide variety of clinical conditions that can significantly alter the ability of the RES to destroy blood cells including hereditary blood cell defects, inflammation, cancer and abnormal immune responses. This lecture will focus on the central role that the spleen plays in not only generating immune responses against platelets but also in primarily causing the destruction of both senescent and antibody-opsonized platelets leading to thrombocytopenia. It will discuss the soluble and cellular mechanisms of splenic sequestration, destruction and the ability of the spleen to modulate anti-platelet immunity. Mechanisms involving complement activation, Fc Receptor-mediated phagocytosis, antibody dependent cellular cytotoxicity and platelet self-destruction will be addressed. It will compare the spleen's platelet destructive capabilities with other organs, particularly the liver and will detail how immune responses generated in the white pulp can modulate platelet destructive processes in the red pulp. Disclosures Semple: Amgen: Consultancy, Honoraria, Speakers Bureau; Rigel: Consultancy, Honoraria; UCB: Consultancy, Honoraria.

Splenomegaly and other disorders of the spleen

2018 ◽  
Author(s):  
Chris Bunch
Keyword(s):  
Particulate Matter ◽  
Immune Responses ◽  
Lymphoid Tissue ◽  
Lymphoid Organ ◽  
Dual Role ◽  
White Pulp ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Upper Abdomen ◽  
Red Pulp

The spleen is a predominantly lymphoid organ, normally about the size of a clenched fist located beneath the diaphragm in the left upper abdomen. It has a dual role as a filter for the circulation, and a primary lymphoid organ in its own right. About three-quarters of its volume is a matrix of capillaries and sinuses (the red pulp), through which blood is able to percolate slowly and come into contact with fixed macrophages, which are able to remove senescent or damaged red cells, or other particulate matter such as bacteria. The lymphoid tissue is organized into scattered follicles (the white pulp), which have a particularly important role in initiating primary humoral immune responses and antibody (IgM) synthesis. The spleen commonly enlarges when either its filtration function is increased—as in haemolysis—or it is stimulated by infection or inflammation. It may also be involved in myeloproliferative and lymphoproliferative neoplasias. This chapter covers hypersplenism, splenectomy, hyposplenism, overwhelming post-splenectomy infection (OPSI), and other infections in hyposplenic patients.

Chitosan-Based Hydrogel Nanoparticles for Cancer Therapy

2017 ◽  
Vol 7 (04) ◽  
Author(s):  
Azadi A. ◽  
Khazaei M. ◽  
Ashrafi H.
Keyword(s):  
Drug Delivery ◽  
Cancer Therapy ◽  
Recent Decade ◽  
Reticuloendothelial System ◽  
Malignant Neoplasms ◽  
Mortality And Morbidity ◽  
Hydrogel Nanoparticles ◽  
Tissue Invasion ◽  
Causes Of Mortality ◽  
Nanoparticulate Systems

Cancer, an uncontrollable growth of cells, is among the leading causes of mortality and morbidity throughout the world. Malignant neoplasms are difficult to treat diseases because of their single in kind characteristics such as tissue invasion, metastasis, evading reticuloendothelial system (RES) and so forth. In recent decade polymeric nanoparticulate systems has gained special attention in drug delivery and targeting among all biocompatible nanoforms. Among these systems, chitosan-based hydrogel nanoparticles have been wildly utilized for drug delivery purposes. The usage of chitosan nanogels in cancer therapy significantly improved in recent years. The various cancers were the target of chitosan nanogels. Also, modification of other delivery systems with chitosan were much reported. The aim of this study is the review and update of the recent studies on chitosan nanogels applications in cancer therapy by focus on cancer based classification.

Imaging of a Rare Case of Diaphragmatic Tumor

2017 ◽  
Vol 3 (1) ◽  
pp. 25-27
Author(s):  
Ajit Reddy ◽  
Anil K Shukla ◽  
Sowmya Anand ◽  
Nitish Suresh
Keyword(s):  
Rare Case ◽  
Surgical Excision ◽  
Malignant Neoplasms ◽  
Primary Tumors ◽  
Contrast Enhanced ◽  
History Of ◽  
Upper Abdominal ◽  
Diaphragmatic Tumor ◽  
Enhanced Computed Tomography ◽  
Upper Abdomen

ABSTRACT Primary tumors of the diaphragm are quite rare. About 150 cases have been reported in the literature. Fibrosarcomas are the most common malignant neoplasms of the diaphragm; however, only a few (less than 20) cases have been reported to date. We present a case of an extremely rare tumor of the diaphragm. A 65-year-old woman presented with history of vague upper abdominal pain since 2 months and distension for 2 weeks. Ultrasonography features were in favor of a mass arising from left dome of diaphragm with evidence of vascularity on Doppler; lesion was displacing spleen inferiorly. Contrast-enhanced computed tomography scan of the abdomen revealed a mass located in the region of the left dome of diaphragm and deriving blood supply from the branches of abdominal aorta. Surgical excision was planned, keeping in mind the diagnosis of a left diaphragmatic tumor. Laparotomy revealed a left diaphragmatic tumor growing caudally into the upper abdomen. How to cite this article Anand S, Suresh N, Reddy AK, Shukla AK. Imaging of a Rare Case of Diaphragmatic Tumor. J Med Sci 2017;3(1):25-27.

scholarly journals Cyclical modulation of sphingosine-1-phosphate receptor 1 surface expression during lymphocyte recirculation and relationship to lymphoid organ transit

2005 ◽  
Vol 201 (2) ◽  
pp. 291-301 ◽  
Author(s):  
Charles G. Lo ◽  
Ying Xu ◽  
Richard L. Proia ◽  
Jason G. Cyster
Keyword(s):  
Lymph Nodes ◽  
Surface Expression ◽  
Lymphoid Organ ◽  
Lymphoid Organs ◽  
White Pulp ◽  
Activated T Cells ◽  
Circulating Lymphocytes ◽  
Sphingosine 1 Phosphate ◽  
Splenic White Pulp ◽  
Lymphocyte Egress

Sphingosine-1-phosphate receptor 1 (S1P1) was recently shown to be required for lymphocyte egress from lymphoid organs. Here we have examined the relationship between S1P1 abundance on the cell and egress efficiency. Using an integrin neutralization approach to separate the processes of entry and exit, we show that pertussis toxin treatment reduces lymphocyte egress from lymph nodes. Retrovirally mediated S1P1 overexpression is sufficient to reduce B cell accumulation in the splenic white pulp and to promote egress of activated T cells from lymph nodes, whereas S1P1+/−cells have reduced lymph node exit efficiency. Furthermore, lymphocyte S1P1 is down-regulated in the blood, up-regulated in lymphoid organs, and down-regulated again in the lymph. We propose that cyclical ligand-induced modulation of S1P1 on circulating lymphocytes contributes to establishing their lymphoid organ transit time.

scholarly journals Structure and function of the immune system in the spleen

2019 ◽  
Vol 4 (33) ◽  
pp. eaau6085 ◽  
Author(s):  
Steven M. Lewis ◽  
Adam Williams ◽  
Stephanie C. Eisenbarth
Keyword(s):  
Cell Types ◽  
Structure And Function ◽  
Lymphoid Organ ◽  
The Body ◽  
Human Spleen ◽  
Cell Clearance ◽  
Wide Range ◽  
Abnormal Cells ◽  
Cell Organization ◽  
And Function

The spleen is the largest secondary lymphoid organ in the body and, as such, hosts a wide range of immunologic functions alongside its roles in hematopoiesis and red blood cell clearance. The physical organization of the spleen allows it to filter blood of pathogens and abnormal cells and facilitate low-probability interactions between antigen-presenting cells (APCs) and cognate lymphocytes. APCs specific to the spleen regulate the T and B cell response to these antigenic targets in the blood. This review will focus on cell types, cell organization, and immunologic functions specific to the spleen and how these affect initiation of adaptive immunity to systemic blood-borne antigens. Potential differences in structure and function between mouse and human spleen will also be discussed.

scholarly journals Cooperating Mechanisms of CXCR5 and CCR7 in Development and Organization of Secondary Lymphoid Organs

2003 ◽  
Vol 197 (9) ◽  
pp. 1199-1204 ◽  
Author(s):  
Lars Ohl ◽  
Golo Henning ◽  
Stefan Krautwald ◽  
Martin Lipp ◽  
Svenja Hardtke ◽  
...  
Keyword(s):  
Functional Organization ◽  
Mesenchymal Cells ◽  
Lymphoid Organ ◽  
Lymphoid Organs ◽  
White Pulp ◽  
Organ Development ◽  
Secondary Lymphoid Organ ◽  
Small Clusters ◽  
Secondary Lymphoid Organs ◽  
Deficient Mice

Homeostatic chemokines participate in the development of secondary lymphoid organs and later on in the functional organization of these tissues. The development of lymph nodes (LNs) and Peyer's patches depends on the recruitment of CD3− CD4+ interleukin (IL)-7Rαhi cells to sites of future organ development. CD3− CD4+ IL-7Rαhi cells express the chemokine receptor CXCR5 and might be attracted by its ligand CXCL13, which is secreted by mesenchymal cells. Mesenchymal cells also secrete CCL19, a ligand for CCR7, yet it is not clear whether CCR7 and CCL19 are important for secondary lymphoid organ development. Analyzing CXCR5−/− CCR7−/− double deficient mice we now show that these mice lack all examined peripheral LNs suggesting a profound role for both receptors in secondary lymphoid organ development. We demonstrate that CD3− CD4+ IL-7Rαhi cells express CXCR5 as well as CCR7 indicating that both receptors cooperate during an early step of secondary lymphoid organ development. Furthermore, CXCR5−/− CCR7−/− mice display a severely disturbed architecture of mesenteric LN and spleen. Due to an impaired migration of B cells into the white pulp, CXCR5−/− CCR7−/− mice fail to develop B cell follicles but show small clusters of unorganized lymphocytes in the spleen. These data demonstrate a cooperative function of CXCR5 and CCR7 in lymphoid organ organogenesis and organization.

Neoplasms of Unknown Primary Site: A Clinicopathological Study of Autopsied Patients

1993 ◽  
Vol 79 (5) ◽  
pp. 321-324 ◽  
Author(s):  
José Ignacio Mayordomo ◽  
Juan Manuel Guerra ◽  
Carlos Guijarro ◽  
María Dolores García-Prats ◽  
Antonio Gómez ◽  
...  
Keyword(s):  
Primary Tumor ◽  
Biliary Tree ◽  
Primary Site ◽  
Unknown Primary ◽  
Malignant Neoplasms ◽  
Unknown Primary Site ◽  
Metastatic Pattern ◽  
Presenting Symptoms ◽  
Complete Physical Examination ◽  
Liver Enlargement

Background Malignant neoplasms of an unknown primary site (NUPS) remain a diagnostic and therapeutic challenge in clinical practice. With this in mind, we have reviewed all autopsies performed in patients with NUPS in a single institution. Patients and methods By reviewing 1656 autopsies performed on adults in our Institution (1974-1990), 43 cases of NUPS were found. (NUPS was defined as histologically proven malignant tumor for which a primary site could not be found after anamnesis, complete physical examination, chest X-ray and routine chemistries.) Results There were 24 men (56 %) and 19 women. Mean age was 62 years (76 % of patients were aged 40-75). Clinical presentation included general deterioration (73 %), digestive symptoms (58 %), liver enlargement (58 %) abdominal pain (56 %), respiratory symptoms (45 %), ascites (26 %) and node enlargement (16 %). Abnormalities in analysis and image tests were frequent but nonspecific. Median time from admission to death was 42 days (range, 4-135). Pathologic diagnoses at autopsy were: 23 adenocarcinomas (53 %), arising from pancreas (6), biliary tree (6), lung (3), prostate (2), stomach (1), kidney (1) and unknown (4); 3 squamous carcinomas (5 %) (1 renal pelvis, 1 biliary tree, 1 stomach); 5 undifferentiated carcinomas (1 lung, 4 unknown); and 12 miscellaneous tumors (including 3 lymphomas, 3 neuroendocrine tumors, 3 hepatocarcinomas, 2 mesotheliomas and 1 melanoma). There was a tendency towards a metastatic pattern different from that expected from the primary tumor. Image tests were of little usefulness in the search for the primary tumor. Conclusions 1) Adenocarciomas were the most frequent tumor presenting as NUPS, especially from the pancreas and biliary tree. 2) In this series, at least 11 % of patients were amenable to standard systemic therapies (3 lymphomas and 2 prostatic adenocarcinomas) if a correct pathologic diagnosis could have been established when alive. 3) Presenting symptoms and metastatic pattern differed from those expected for the primary neoplasm eventually found. 4) Image tests were often misleading as regards the primary site, although they were useful to quantify the dissemination of the tumor.

scholarly journals Fatal Plasmodium falciparum Malaria Causes Specific Patterns of Splenic Architectural Disorganization

2005 ◽  
Vol 73 (4) ◽  
pp. 1986-1994 ◽  
Author(s):  
Britta C. Urban ◽  
Tran T. Hien ◽  
Nicholas P. Day ◽  
Nguyen H. Phu ◽  
Rachel Roberts ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Malaria ◽  
Severe Disease ◽  
Plasmodium Falciparum Malaria ◽  
Lymphoid Organ ◽  
White Pulp ◽  
Human Malaria ◽  
Hla Dr ◽  
Repeated Infections ◽  
Marginal Zones

ABSTRACT The spleen is critical for host defense against pathogens, including Plasmodium falciparum. It has a dual role, not only removing aged or antigenically altered erythrocytes from the blood but also as the major lymphoid organ for blood-borne or systemic infections. The human malaria parasite P. falciparum replicates within erythrocytes during asexual blood stages and causes repeated infections that can be associated with severe disease. In spite of the crucial role of the spleen in the innate and acquired immune response to malaria, there is little information on the pathology of the spleen in human malaria. We performed a histological and quantitative immunohistochemical study of spleen sections from Vietnamese adults dying from severe falciparum malaria and compared the findings with the findings for spleen sections from control patients and patients dying from systemic bacterial sepsis. Here we report that the white pulp in the spleens of patients dying from malaria showed a marked architectural disorganization. We observed a marked dissolution of the marginal zones with relative loss of B cells. Furthermore, we found strong HLA-DR expression on sinusoidal lining cells but downregulation on cordal macrophages. P. falciparum infection results in alterations in splenic leukocytes, many of which are not seen in sepsis.

scholarly journals To Study the causes of Industrial Sickness in Nanded District (Maharashtra)

2017 ◽  
Vol 4 (37) ◽  
Author(s):  
Balaji S. Mudholkar
Keyword(s):  
Drug Delivery ◽  
Cancer Therapy ◽  
Recent Decade ◽  
Reticuloendothelial System ◽  
Malignant Neoplasms ◽  
Mortality And Morbidity ◽  
Tissue Invasion ◽  
The World ◽  
Causes Of Mortality ◽  
Nanoparticulate Systems

Cancer, an uncontrollable growth of cells, is among the leading causes of mortality and morbidity throughout the world. Malignant neoplasms are difficult to treat diseases because of their single in kind characteristics such as tissue invasion, metastasis, evading reticuloendothelial system (RES) and so forth. In recent decade polymeric nanoparticulate systems has gained special attention in drug delivery and targeting among all biocompatible nanoforms. Among these systems, chitosan-based hydrogel nanoparticles have been wildly utilized for drug delivery purposes. The usage of chitosan nanogels in cancer therapy significantly improved in recent years. The various cancers were the target of chitosan nanogels. Also, modification of other delivery systems with chitosan were much reported. The aim of this study is the review and update of the recent studies on chitosan nanogels applications in cancer therapy by focus on cancer based classification.

Sign in / Sign up

Export Citation Format

Share Document