Mesenchymal tissue

PDGF Isoforms consist of homo- and heterodimers of A- and B-polypeptide chains and homodimers of C- and D-polypeptide chains PDGFR Consists of PDGFR a and (3 receptors Embryonic development, particularly in the formation of the kidney, blood vessels, and various mesenchymal tissues. Proliferation of connective tissues, glial and smooth muscle cells... 

Mesenchymal tissue is immature, unspecialized tissue, found in the early embryo of animals, whereas epithelial cells are parenchymal cells that line an internal cavity or tube. 

Gunn SA, Gould TC, Anderson WAD Specific response of mesenchymal tissue to cancerogenesis by cadmium. Arch Pathol 83 483-499, 1967... 

Mesenchymal stem cells (MSCs) are multipotent cells that contribute to the regeneration of mesenchymal tissues such as bone, cartilage, muscle, ligament, tendon, adipose and marrow stroma [394517], [656539]. MSCs represent an important cellular component of the BM microenvironment [656703] and can be easily isolated from the adult BM stroma, where they represent a rare population of the cells (estimated at 0.001 to 0.01% of the nucleated cells, 10-fold less abundant than HSCs) [658632], [658640]. MSCs have also been found in umbilical cord blood, but not peripheral blood [658631]. Once isolated, MSCs can be expanded in culture through many generations, producing billions of MSCs for cellular therapy [656543]. 

Isolated animal cells in tissue culture, no matter how highly differentiated, tend to revert quickly to one of three basic types known as epitheliocytes, mechanocytes, and amebocytes. Epitheliocytes are closely adherent cells derived from epithelial tissues and thought to be related in their origins to the two surface layers of the embryonic blastula. Mechanocytes, often called fibroblasts or fibrocytes, are derived from muscle, supporting, or connective tissue. Like the amebocytes, they arise from embryonic mesenchymal tissue cells that have migrated inward from the lower side of the blastula (Chapter 32). Neurons, neuroglia, and lymphocytes are additional distinct cell types. 

Fishman and coworkers,220 reported that, following an oral dose of 5 to 10 g. of D-glucuronolactone, about 16% was excreted in the urine as D-glu-curonic acid by normal, human subjects. An intravenous dose of 2 to 3 g. was followed by the excretion of 46-65%.219 221 The data of Fretwurst and Ahlhelm222 are similar. Quantitative differences in D-glucuronolactone metabolism in arthritic, hepatic, and mesenchymal tissue diseases were claimed to have been found by the above workers, but the differences were generally not remarkable. 

A boy with Menkes disease and low plasma concentrations of copper (3.6 pmol/l) and ceruloplasmin (50 mg/1) received copper histidine and died aged 10. Postmortem examination showed significant pathology of the mesenchymal tissues, including skeletal abnormalities, vascular degeneration, and bladder diverticula. The central nervous system, in contrast, showed minimal pathology of copper metabolism compared with classical Menkes disease. 

The differential sensitivity of central nervous system and mesenchymal tissues to copper histidine may be due to heterogeneity in the responses of different copper-dependent enzymes. 

A malignant neoplasm that contains elements of carcinoma and sarcoma so extensively intermixed as to indicate neoplasia of epithelial and mesenchymal tissue. 

A second member of the parathyroid hormone family, parathyroid hormone-related protein (PTHrP), is quite similar to PTH in amino acid sequence and protein structure. Like PTH, it activates the parathyroid hormone receptor causing increased bone resorption and renal tubular calcium reabsorption. Increased serum concentrations of parathyroid hormone-related protein are the predominant cause of hypercalcemia in cancer patients with solid tumors. This observation led to its discovery and to the elucidation of its many cellular functions in normal tissues. In contrast to PTH, which is expressed only in parathyroid glands, PTHrP is detected in many tissues in fetuses and adults it is found in epithelia, mesenchymal tissues, endocrine glands, and the central nervous system. This protein is also the principal regulator of placental calcium transport to the fetus. 

Vimentin, an intermediate filament, is expressed in mesenchymal tissues, normal proliferative endometrial epithelial cells, and in the majority of endometrial carcinomas.jj g coexpression of vimentin and low molecular weight cytokeratin can aid in the differential diagnosis of an endocervical versus an endometrial adenocarcinoma. 

Vainio, S., Karavanova, I., Jowett, A., Thesleff, I. 1993. Identification of BMP-4 as a signal mediating secondary induction between epithelial and mesenchymal tissues during early tooth development. Cell 75, 45-58. 

Noden, D.M. 1986b. Origins and Patterning of Craniofacial Mesenchymal Tissues, Journal of Craniofacial Genet, and Dev. Biol. Supplement 2, 15-31. 

Perhaps the most characterized stem cell is the one residing in the adult bone marrow - that is, the hematopoietic stem cell which gives rise to aU blood cell types [73]. In addition, mesenchymal stem cells (MSC) are multipotent cells that can be isolated from adult bone marrow and be induced in vitro and in vivo to differentiate into a variety of mesenchymal tissues, including bone, cartilage, tendon, fat, bone marrow stroma, and muscle [74]. 

Michotte has suggested that biolt ical oxidation processes in mesenchymal tissues require a balance of C -hydroxysteroids and adrenergic substances, and this is disturbed in rheumatic diseases owing to the failure of the adrenergic component. It is alleged that pyrocatechoic acid (V) may replace this component, restore the physiological imbalance and, consequently, suppress the inflammatory reaction. Adams and Cobb found that neither pyrocatechoic acid nor its diacetyl derivative administered orally inhibits ultra-violet erythema in the guinea-pig. The former compound, administered subcutaneously, reduces vascular permeability in the mouse peritoneum, but the effect is less than that of salicylic acid . Other dihydroxybenzoic acids tested are not active in this system . 

Peters, K.G., Werner, S., Chen, G. and Williams, L.T. (1992) Two FGF receptor genes are differentially expressed in epithelial and mesenchymal tissues during limb formation and organogenesis in the mouse. Development 114 233-243. 

Collagen fibrils are generally expected in mesodermal or mesenchymal tissues, or in the mesoglea when typical mesoderm is not developed, as in the Coelenterata and Porifera. Table I summarizes the varieties of collagen which have been identified in sources of this kind and by the physical methods described immediately above. 

The special group would scarcely be recognized as collagens except for the diffraction evidence. They arise not from obviously mesenchymal tissue but from epithelial cells or glands, sometimes of non-mesodermal origin. In a sense, therefore, they may not deserve the term collagen, ... 

These cells arise from interstitial mesenchymal tissue between the tubules during the eighth week of human embryonic development. They are located in the connective tissue between the seminiferous tubules, Leydig cells are the endocrine cells in testis that produce testosterone from cholesterol via a serie.s of enzymatic pathways and steroidal intermediates under the control of luctinizing hormone (LH) from pituitary. The effects of testosterone can be grouped into the following categories ... 

Synthesis of specific TGF-/1 superfamily member proteins as markers of bone formation by induction from resident transformed osteoblast-like cells onto the sintered crystalline hydroxyapatite as shown by immunolocalization of OP-1 and BMP-3 within the cellular cytoplasm and at the interface of the hydroxyapatite biomatrix with the invading mesenchymal tissue [23,24, 65]. 

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