Tissue substrates

There are different types of cholinesterases in the human body, and they differ in their location in tissues, substrate affinity, and physiological function. The main ones are ACHE, present in nervous tissue and red blood cells (RBC-ACHE), and plasma cholinesterases (PCHE), present in glial cells, plasma, and liver. The physiological functions of RBC-ACHE and PCHE, if any, are unknown. 

Tissue substrate (i.e., lipid-rich plaque) Fibrinogen, impaired fibrinolysis (i.e., PMI-1), activated platelets and clotting (i.e., factor VII, thrombin generation, FI + 2)... 

CYP2A6 is responsible for the majority of coumarin 7-hydroxylase and nicotine C-oxidase activity in hepatic tissue. Substrate selectivity of 2A6 and 2A5 (mouse enzyme) was studied using 23 lactone-containing compounds... 

When healthy volunteers were exposed by inhalation to 100 or 400 ppm tetrahydrofuran in air, the percentage of expired tetrahydrofuran was 25-35%. The elimination half-life of tetrahydrofuran was 30 min in individuals exposed to 200 ppm for 3h. Some tetrahydrofuran is absorbed in the nasal cavity due to its solubility and inspiratory flow rate. Tetrahydrofuran uptake in the nasal tissue is dependent on its reaction with tissue substrates. Some tetrahydrofuran can be metabolized in the nasal cavity. Tetrahydrofuran blood concentrations were higher at 1 h postexposure than immediately after cessation of exposure. In vitro studies indicated that tetrahydrofuran was first hydroxylated by microsomal enzymes. High concentrations (lO molH ) of tetrahydrofuran inhibited the in vitro activity of rat hepatic cytochrome P450 by 80%. Tetrahydrofuran has been noted to enhance the toxic action of a number of compounds and stimulate the rapid absorption of reactive metabolites. Some of the tetrahydrofuran is excreted in the exhaled breath, while the various metabolites of tetrahydrofuran are excreted in the urine. 

Dissolving hard-tissue substrate will modify the composition of experimental solutions, with which it is in contact. This behaviour reflects the in vivo situation, where dissolved mineral from the teeth can reduce undersaturation during an acidic challenge. 

Mellberg JR Hard-tissue substrates for evaluation of cariogenic and anti-cariogenic activity in situ. J Dent Res 1992 71(Sp Iss) 913-919. 

PMN Products - Neutral proteinases of PMN lysosomes degrade a wide variety of collective tissue substrates including elastin, proteoglycan, and collagen. Cathepsin G has been found only in PMN, and elastase from these cells has a substrate gpecificity different from that of pancreatic and macrophage elastase. In addition to their effects on connective tissue components, the neutral proteinases of PMN lysosomes also stimulate the activity of other cells involved in the inflammatory response. Both elastase and cathepsin G from human PMN stimulate the incor- poration of thymidine by human peripheral blood and splenic lymphocytes. The stimulated lymphocytes are of the B lineage, with no effect seen on T lymphocytes. 

Since this enzyme was first isolated and purified from swine lung [106], a number of papers have been published reporting its occurrence in animal tissues, substrate specificity, enzyme inhibitors, reaction mechanism and physiological function. These papers have been anteceded by two comprehensive review articles [107,108]. 

Gene Aliases Tissue Substrate Inhibitor Inducer... 

This indicates an apparent competition between the methoxy and hydroxy nucleophiles for the initiation of the polymerization. Polymers prepared in aqueous solutions of pyridine, cysteine, alanine and glycine, show also a suppression of the OH band, suggesting that nucleophiles other than the OH may preferably be involved in the initiation of the polymerization. This fact has important consequences for in vivo applications of PACA as adhesives, since such initiation of the monomer could lead to primary chemical bonding of the adhesives to the tissue substrate. 

Takamizawa, K., Shoda, K., Matsuda, T. (2002). PuU-out mechanical measurement of tissue-substrate adhesive strength endothelial ceU monolayer sheet formed on a thermorespHjnsive gelatin layer. Journal of Biomaterials Science Polymer Edition, 13, 81-94. 

Plant tissue Substrate VLCFA synthesis (nmol/ng prot/h) Sribcellular Heferenc locatioi ... 

Cell culture substrates Eardrum plugs Synthetic cartilages Hemodialysis membranes Breast or other soft-tissue substrates Particulate carriers of tumor antibodies Vitreous humor replacements ... 

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