Epithelial cell

In some cells of the body, such as muscle cells, the chloride concentration may be as low as 10 milliequivalents per liter, while In other cells, such as the epithelial cells lining the stomach and intestines, the chloride concentration Is approximately the same as in the extracellular fluid. In those cells where the chloride concentration Is low, the aquation reaction will occur to some degree. This Is the only step necessary to activate the drug. The equated species are now able to react with various intracellular molecules, and In particular, the nucleic acids. Evidence from both In vitro and In vivo 

It is quite clear by now that drug action of the dichloro-dlammlneplatlnum (II) is stereoselective. For anticancer activity to occur the drug must be in the cis configuration. The trans Isomer Is Inactive. This is true for all the other analogs 

Of this sub-class of reactions, one is most Interesting. This is the formation of a closed ring chelate of clsplatln with the N-7 and 0-6 nucleophilic sites of guanine. It had been shown previously that the clsplatln reacted primarily with the GC rich regions of DNA. It has also been suggested that the tertiary structure of DNA is probably too plastic to exhibit the necessary stereoselectivity. It is also known that the clsplatln does not 

ACS Symposium Series American Chemical Society Washington, DC, 1980. 

This then leads on further replication to the replacement of the original GC pair by an AT palr-a base substitution mutation. Whether such mutations need to occur in particular regions of the DNA is not yet clear. 

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In adults, a few areas may require further study. For example, there is a report of soya consumption causing an increased incidence of hyperplastic epithelial cells in the nipple aspirate fluid of pre- and postmenopausal women.This could constitute a risk factor for breast cancer. Also, the use in herbal medicine of particular plants emphasises that these species have the potential to cause physiological changes. Consequently, the increasing public interest in the use of herbal medicines could lead to unintended (adverse) effects, particularly as most... 

Artifacts introduced through sample preparation are common materials these may be bits of facial tissue, wax, epithelial cells, hair, or dried stain, all inadvertently introduced by the microscopist. Detergent residues on so-called precleaned microscope slides and broken glass are common artifacts, as are knife marks and chatter marks from sectioning with a faulty blade, or scratch marks from grinding and polishing. 

Airway cross-sections have the nominal anatomy shown in Fig. 5.16. Airway surface liquid (AST), primarily composed of mucus gel and water, surrounds the airway lumen with a thickness thought to vary from 5 to 10 mm. AST lies on the apical surface of airway epithelial cells (mostly columnar ciliated epithelium). This layer of cells, roughly two to three cells thick in proximal airways and eventually thinning to a single cell thickness in distal airways, rests along a basement membrane on its basal surface. Connective tissue (collagen fibers, basement membranes, elastin, and water) lies between the basement membrane and airway smooth muscle. Edema occurs when the volume of water within the connective tissue increases considerably. Interspersed within the smooth muscle are respiratory supply vessels (capillaries, arteriovenous anastomoses), nerves, and lymphatic vessels. 

Cilia are thin cylindrical hair-like structures with a cross-sectional radius of 0.1 gm projecting from the apical epithelial surface of ciliated columnar cells. Ciliary length is thought to correspond to periciliary fluid depth and range from approximately 7 gm in proximal airways to roughly 5 gm in more distal airways.- Each ciliated epithelial cell supports approximately 200 cilia at a density of eight cilia/gm. Short microvilli, possibly associated with secretory functions, are interspersed among the cilia. 

Nonciliated cells separate fields of ciliated epithelial cells from each other. Synchronized ciliary movement, with a beat frequency in human proximal airways under normal conditions of 8-15 EIz, propels mucus along the mucociliary escalator at a rate of up to 25 mm/min. Beat frequencies appear to slow to roughly 7 Hz in more distal airways. Cilia move in the same direction and in phase within each field but cilia in adjacent fields move in slightly different directions and are phase shifted. These beat patterns result in metachronal waves that steadily move mucus at higher velocities ( -12-18 mm/min) than would be achievable by summing the motion of individual cilia. 

Squamous epithelium Flattened, interlocking, toughened epithelial cells. 

Transepithelial Passing across a layer of epithelial cells. 

Marsh, J. P., and Mossman, B. L (1991) Role of asbestos and active oxygen species in. ictiva-rion. and expression of ornirhinc decarboxylase in hamster tracheal epithelial cells. Cancer Ra. 51(1), 167-173. 

FIGURE 24.4 In the small intestine, fatty acids combine with bile salts in mixed micelles, which deliver fatty acids to epithelial cells that cover the intestinal villi. Triacylglycerols are formed within the epithelial cells. 

Epithel, n. epithelium, -zelle, /. epithelial cell. Epizuckersaure, /. episaccharic acid. 

Cue D, Southern S, Southern P et al (2000) A non-peptide integrin antagonist can inhibit epithelial cell ingestion of streptococcus pyogenes by blocking a5 31 -fibronectin-Ml protein complexes. Proc Nat Acad Sci 97(6) 2858-2863... 

Refers to the aspect of epithelial cells facing the mucosal (as opposed to serosal) side of the cells. 

Cadherins are a superfamily of Ca2+-sensitive cell-cell adhesion molecules, which cause homophilic cell interactions. Cadherins can be divided into different subfamilies, namely, classical cadherins, desmosomal cadherins, protocadherins, and nonconventional cadherins (7TM cadherins, T-cadherin, FAT). Classical cadherins are often denoted by a prefix reflecting their principal expression domains e.g., E is epithelial, N is neuronal, and P is placental. However, this classification is not stringent, as for instance E-cadherin can also be found in certain neuronal tissues, and N-cadherin is also found in epithelial cells. Among the desmosomal cadherins, two subfamilies can be distinguished the desmocollins 1-3 and the desmogleins 1-4. 

Classical and desmosomal cadherins are constituents of different types of intercellular junctions. E-cadherin, the classical cadherin of epithelial cells, is part of the adherens junction (zonula adherens), which is attached to a belt of actin via the catenins. As the name says, desmosomal cadherins are part of the desmosomes, which are rivet-like structures that make focal connections between cells. Desmosomes are characterized by a... 

Basic (pH) proteins directed against pathogens. Examples are the major basic protein from mast cells, the eosinophilic cationic proteins from eosinophils, and defensins from epithelial cells and neutrophilic granulocytes. 

Endothelial cells are the major source of ET-1-synthesis. ET-1 is also produced by astrocytes, neurons, hepatocytes, bronchial epithelial cells, renal epithelial and mesangial cells. Physiological stimuli of ET-1-synthesis in endothelial cells are angiotensin II, catecholamines, thrombin, growth factors, insulin, hypoxia and shear stress. Inhibitors of ET-1 synthesis are atrial natriuretic peptide, prostaglandin E2 and prostacyclin. ET-2 is mainly synthesized in kidney, intestine, myocardium and placenta and ET-3 is predominantely produced by neurons, astrocytes and renal epithelial cells. 

Sites of endothelin-receptor expression. ETA receptors are expressed in the smooth muscle cells of the vascular medial layer and the airways, in cardiac myocytes, lung parenchyma, bronchiolar epithelial cells and prostate epithelial cells. ETB receptors are expressed in endothelial cells, in bronchiolar smooth muscle cells, vascular smooth muscle cells of certain vessels (e.g. saphenous vein, internal mammary artety), in the renal proximal and distal tubule, the renal collecting duct and in the cells of the atrioventricular conducting system. 

In malignant prostate epithelial cells, auto- and paracrine release of ET-1 is a critical factor in ETA receptor-mediated proliferation [5]. In addition, the ET-1/ETa receptor axis has emerged as a potential target in prostate cancer bone metastasis... 

Epithelial calcium channel 1 (ECaCl), synonym TRJPV5, is a member ofthe TRP family of ion channels, implicated in vitamin D-dependent transcellular Ca2+ transport in epithelial cells ofthe kidney, placenta and the intestine. 

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