Human gastrointestinal tract, characteristics

The human histamine Hi-receptor is a 487 amino acid protein that is widely distributed within the body. Histamine potently stimulates smooth muscle contraction via Hi-receptors in blood vessels, airways and in the gastrointestinal tract. In vascular endothelial cells, Hi-receptor activation increases vascular permeability and the synthesis and release of prostacyclin, plateletactivating factor, Von Willebrand factor and nitric oxide thus causing inflammation and the characteristic wheal response observed in the skin. Circulating histamine in the bloodstream (from, e.g. exposure to antigens or allergens) can, via the Hi-receptor, release sufficient nitric oxide from endothelial cells to cause a profound vasodilatation and drop in blood pressure (septic and anaphylactic shock). Activation of... 

The toxicokinetics of disulfoton in humans and animals depends on its physicochemical characteristics and its metabolism. The lipophilicity of disulfoton indicates that the insecticide should be easily absorbed by oral, inhalation, and dermal routes. No bioavailability data were located for inhalation and dermal exposure. However, disulfoton is almost completely absorbed from the gastrointestinal tract within 2 days after oral exposure. Animal studies suggest that disulfoton is widely distributed primarily to the liver and in smaller quantities to the kidney, fat, skin, muscle, brain, and other organs. Disulfoton and/or its metabolites are excreted mainly in the urine of humans and animals, with minor amounts excreted in the feces and expired air. 

The particular complexities of antibody pharmacokinetics and their relationship to pharmacodynamics have been thoroughly reviewed by Lobo and coworkers [16]. Many of the characteristics discussed above for macromolecules in general also apply in the case of antibodies. Thus, absorption following subcutaneous or intramuscular administration may be slow, with involvement of lymphatic transport, and attainment of peak blood concentrations may take days. Although absorption of antibodies from the gastrointestinal tract following oral administration to adult humans is very limited, absorption of IgG from the gastrointestinal tract of neonates of several species has been demonstrated [34]. This absorption occurs via interaction with the neonatal receptor for... 

Theory and Equipment. Many diseases of the human body can be identified by visual appearance. Tumors in the upper gastrointestinal (GI) tract, for example, possess a characteristic salmon pink color (3). The presence of such a color can be an indication of disease. Endoscopy is the medical imaging tool used to detect such colors in the inside of hoUow internal organs such as the rectum, urethra, urinary bladder, stomach, colon, etc. An endoscope is the instmment used to perform endoscopy. Endoscopic imaging involves the production of a tme color picture of the inside of the human body using lenses and either hoUow pipes, a fiber optic bundle, or a smaU CCD camera. AU three use a large field-of-view, sometimes referred to as a fish eye, lens to aUow a 180° field of view. 

Infections with helminths, or parasitic worms, affect more than two bilhon people worldwide. Pathogenic worms are classified into roundworms (nematodes) and two types of flatworms, flukes (trematodes) and tapeworms (cestodes). Immature forms invade humans via the skin or gastrointestinal (GI) tract and mature into adult worms with characteristic tissue distributions. With few exceptions, such as Strongyloides and Echinococcus, they cannot complete their life cycle and replicate themselves within the human host. 

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