Epithelial tissues placenta

Cadherins are transmembrane glycoproteins that are prime mediators of cell-cell adhesion via calcium-dependent interactions. Different members of the family are found in different locations (e.g., E-cadherin is found in epithelial tissue, N-cadherin is found in muscle and adult neural tissues, P-cadherin is found in the placenta). 

Vitamin A (retinol) (Fig. 7.12) and its metabolic oxidation products assume a critical physiological role in growth, development and differentiation of epithelial tissue, the maintenance of vision, and as well in spermatogenesis and the normal development of the placenta and the foetus. (allE)-Retinoic acid and (13Z)-retinoic acid are important medicaments for the treatment of acne and psoriasis the former has also demonstrated complete remission in most cases of acute promyelocytic leukemia (APL). 

In contrast to P-gp and the MRP proteins, the breast cancer resistance protein (BCRP) contains six transmembrane domains and only one ATP-binding domain. It was first cloned from the breast cancer cell line MCF-7 selected in doxombicin, in the presence of the P-gp inhibitor verapamil. It is found in many human tissues, such as the placenta, small intestine, colon, and liver [133], It is localized to the apical membrane of epithelial cells of the small intestine and colon and to the bile canalicular membrane in the liver and is involved in reducing intestinal uptake, increasing hepatobiliary excretion, etc., leading to diminished oral bioavailability. cDNA sequences identical to BCRP and named MXR and ABCP, respectively, were independently isolated from human colon carcinoma cells and human placenta [134], BCRP requires... 

Used for ocular bums as soon as 1947 by Sorsby [30], the amniotic membrane is a tissue located at the interface of the placenta and the amniotic fluid. It is constituted of an unstratifled epithelium, a basement lamina, and an avascular mesenchyma. The amniotic membrane facilitates the reepithelialization by reducing the inflammatory and cicatricial reaction [31]. It helps the migration of the epithelial cells and the adhesion of the basement cells [32]. It behaves as an actual replacing basement membrane and facilitates the phenotypic... 

BCRP is classified in ABCG subfamily other members of this subfamily are involved in sterol transport (269). Unlike P-gp and MRPs, BCRP consists of a single ABC cassette in the amino terminal followed by six putative transmembrane domains however, it forms a homodimer linked by a disulfide bond in the plasma membrane (270,271). Initially, ABCG2 was identified as an mRNA expressed in placenta (272) and as a non-MDRl- and non-MRP-type resistance factor from cell lines selected in the presence of anthracy-clines and mitoxantrone (273). BCRP is expressed widely in the normal tissues (274) and localized on the canalicular membrane of the hepatocytes and apical membranes of epithelial cells (274,275) and brain capillary endothelial cells (276,277). 

Acetylcholine is the neurotransmitter at all these sites, acting on a postsynaptic receptor, except on most blood vessels in which the action of cholinergic drugs is unrelated to cholinergic vasodilator nerves. It is also produced in tissues unrelated to nerve endings, e.g. placenta and ciliated epithelial cells, where it acts as a local hormone (autacoid) on local receptors. 

IL-15 is produced by multiple cellular and tissue sources (blood mononuclear cells, placenta, skeletal muscle, kidney, lung, liver, heart, bone marrow stromal cells, keratinocytes, Langerhans" cells, and other tissue-specific dendritic cells) and particularly by epithelial cells and monocytes (Figure 22-23)."" " " ... 

BCRP (also known as ABCG2) is a half ABC transporter. It is sometimes known as mitoxantrone resistance protein (MXR) because of its elevated expression in many cancer cell lines selected with mitoxantrone [54]. BCRP was first identified in breast cancer, but it is also found in several normal tissues, including placenta, liver canaliculi, small intestine, colon, the bronchial epithelial layer in the lung, and endothelial cells [55]. Its level is also elevated in other cancer types. For instance, an analysis of 150 untreated tumors with immuno-histochemical technique demonstrated a high incidence of BCRP overexpression particularly in tumors of gastrointestinal origin [56]. Elevated BCRP level is consistently associated with the phenotype that includes strong resistance to mitoxantrone, moderate resistance to anthracyclines, and sensitivity to... 

Efflux pumps are transmembrane located transporter proteins which are expressed in various tissues including liver, placenta, the proximal tubule in the kidney, capillary endothelial cells of brain and testis, and epithelial cells of the intestine [1,2]. In addition, they are over-expressed in cancer cells and are involved in the multi drug resistance (MDR) mechanisms of tumors. Besides other mechanisms such as CYP3A, efflux pumps constitute an integral part of the body s natural detoxification system. Due to their loealisation in various tissue they affect absorption, distribution, metabolism and elimination [3]. They are... 

General metabolic significance. (1) Somatic functions growth, development, and differentiation of epithelial and bone tissue (retinol, retinal, retinoic acid). (2) Reproduction spermatogenesis, development of the placenta, embryonic growth (retinol, retinal). (3) Visual process 11-cis-retinaldehyde is a prosthetic group of the visual pigments. 

---