Lymphatics spleen

Lymphoreticular Effects—Represent morphological effects involving lymphatic tissues such as the lymph nodes, spleen, and thymus. 

In comparison to intravenous administration of MLV, which usually results in a rapid and almost quantitative uptake into liver and spleen, the fraction taken up into these organs is lower after intraperitoneal injection of these large liposomes. The reason might be that liposomes are trapped in lymph nodes and degradation of the liposomes in the peritoneal cavity can occur (Ellens et al., 1981 Parker et al., 1982) besides, several types of liposomes are degraded more quickly in lymphatic fluid than in plasma (Parker et al, 1981a,b). 

Lymphatic system The tissues and organs that produce, store, and carry white blood cells that fight infection and disease. This system includes the bone marrow, spleen, thymus, and lymph nodes and a network of thin tubes that carry lymph and white blood cells. 

Irrespective of size, liposomes, when injected in-traperitoneally, partially accumulate in the liver and spleen. It has been suggested that transport of liposomes from the peritoneal cavity to the systemic circulation, and eventually to tissues, occurs by lymphatic pathways. Local injection of larger liposomes leads to quantitative accumulation at the site of injection. The slow disintegration of the carrier than releases the drug, which diffuses into the blood circulation. Smaller liposomes, on the other hand, enter the lymph nodes and blood circulation and eventually accumulate in the liver and spleen. 

This is a diffnse and loosely dehned system which encompasses those cells and tissnes that are phagocytic. These include the endothelia of blood and lymphatic vessels (which are only weakly phagocytic), reticnlar cells of the spleen, endothelial cells, sinnsoids in the liver and lymph nodes, macrophages and drcnlating phagocytes. 

Simon, in 1845, described the thymus as an early critical barometer of nutrition (Sll) and Hammar (HI) was so impressed by the characteristic lesions produced in the thymus by malnutrition (Jl) that he applied the term accidental involution to describe the atrophied changes produced in the thymus by malnutrition. Of all the thymolymphatic organs the thymus first showed the most pronounced involution in the malnourished individuals, followed by the spleen (A8) and then the rest of the lymphatic organs (.15) (Table 4). 

Postmortem examinations of persons who died as a result of exposure to H have shown depletion of lymphoid cells in the spleen, thymus, and other lymphatic organs depletion of hematopoietic cells of the bone marrow necrosis and desquamation of epithelium in the small intestine acute ulceration of the duodenum membranous laryn-gotracheobronchitls and pulmonary edema, congestion, and patchy emphysema that may be complicated by bronchopneumonia or other evidence of pulmonary infection.2>47... 

On the other hand, polycyclic aromatic compounds given orally or subcutaneously are more likely to cause aplastic anemia, leukemia, and lymphatic tumors in Ah-nonresponsive mice. These effects are manifest in tissues distant from the site of drug administration. In the example of oral benzo[a]pyrene, pharmacokinetic studies have shown a 10-and 20-fold higher uptake in the marrow and spleen of Ah-nonresponsive than of Ah-responsive mice this confirms the phenomenon called "first-pass elimination kinetics."... 

Lymph vessels These are part of the lymphatic system, made up of vessels, nodes and organs such as the spleen and tonsils. Important funchons for the body include internal defensive mechanisms. The lymph vessels form a tubular network throughout the body carrying a fluid called lymph. Lymph is made up of a colourless fluid containing white blood cells that is collected from the tissues of the body. The lymph vessels pick up and regulate the tissue fluid formed by the bloodstream, which bathes and nourishes the cells. The lymph is circulated through the lymphatic vessels and is eventually returned to the bloodstream. 

Changes in leukocyte count and differential leukocyte count (Den Tonkelaar et al. 1983) may suggest pathological changes in lymphatic tissue, spleen, and thymus. Based on the limited human and animal data, the potential for DNOC to cause immunological effects in humans cannot be ruled out. 

In oral administration of ricin in mice, the approximate LD50 dose is 20mg/kg with time to death up to 85 h (Fodstad et al, 1979). In a rat study, ricin was absorbed in the lymphatic blood vessels and largely distributed in the spleen and liver within 2 h of ingestion (Ishiguro et al, 1983). The study also demonstrated that up to 72 h after ingestion, approximately 20-45% of ricin is excreted in the feces (Ishiguro et al, 1992). 

SAFETY PROFILE Poison by intraperitoneal route. Moderately toxic by ingestion, subcutaneous, and intravenous routes. Human teratogenic effects by unspecified route developmental abnormalities of the blood and lymphatic systems (including the spleen and bone marrow). Experimental reproductive effects. Questionable carcinogen with experimental carcinogenic data. Mutation data reported. Implicated in aplastic anemia. When heated to decomposition it emits very toxic fumes of NOx and SOx. 

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