(n.) The chemical basis of ordinary connective tissue, as of tendons or sinews and of bone. On being boiled in water it becomes gelatin or glue.
Example Sentences:
(1) Collagen production of rapidly thawed ligaments was studied by proline incubation at 1 day, 9 days, or 6 weeks after freezing and was compared with that of contralateral fresh controls.
(2) The rate of accumulation of degraded LDL products was lower in collagen gel cultures, but the final levels achieved were the same in the two substrata.
(3) In the present study, the expression of type IV collagen associated with the basal membrane (BM) was studied histochemically (indirect immunoperoxidase-antiperoxidase) in cervical human papillomavirus (HPV) lesions (diagnosed using in situ DNA hybridization) of different grades.
(4) Both Types I and II collagen are important constituents of the affected tissues, and thus defective collagens are reasonable candidates for the primary abnormality in adolescent idiopathic scoliosis (AIS).
(5) Furthermore, overlap syndromes between the different autoimmune liver diseases as well as with other disorders including collagen disorders can be observed.
(6) When cultures were pulse labeled for 15 min and then incubated under chase conditions for 105 min, the amount of degraded collagen attained a value equal to approximately 20% of the amount synthesized during the labeling period; the data were fit with a simple exponential function that had a 40-min rise time and a 12-min lag time.
(7) At concentrations several hundredfold higher than the equivalents present in the minimum concentration of rat skin soluble collagen required for platelet aggregation, neither Hyl-Gal (at 29 muM) nor Hyl-Gal-Glc (at 18 muM) caused platelet aggregation or inhibited platelet aggregation by native collagen.
(8) However, cimetidine did not show any effect on the proliferation of collagenous fibers in the interstitial space of the mucosa.
(9) Electron microscopic observations of the masseter nerve in the aged cats revealed a disruption of the myelin sheaths and a pronounced increase in collagen fibers in the endoneurium and perineurium.
(10) The kinetic parameters for the hydrolysis of type I, II and III collagens have been measured and are similar in magnitude to those for the tissue collagenases.
(11) Increased amounts of laminin in the basal epithelium of the cornea and of collagen type III in the stroma and subepithelial components of the stroma were observed.
(12) The formation of auto-antibodies directed against laminin and type IV collagen is probably caused by restricted polyclonal B cell stimulation, a well known feature of trypanosomiasis.
(13) We found that when neutrophils were allowed to settle into protein-coated surfaces the amount of O2- they generated varied with the nature of the protein: IgG greater than bovine serum albumin greater than plastic greater than gelatin greater than serum greater than collagen.
(14) Pathologic examination demonstrates calcifications in the dead collagen that makes up catgut suture.
(15) Human Caco-2 enterocytes were cultured on matrix proteins (collagen I, laminin, fibronectin) with growth factors (epidermal growth factor [EGF] and transforming growth factor-beta 1 [TGF-beta 1]) and the tyrosine kinase and prostaglandin inhibitors genistein and indomethacin.
(16) In other experiments, the cells incorporated [3H]lysine into hydroxylysine residues of cell-associated collagen and then 32P into phosphohydroxylysine residues.
(17) On the other hand, ultraviolet (320-nm) light, absorbed by 3-hydroxy-pyridinium cross-links which were rapidly photolyzed, partially dissociated polymeric collagen aggregates from bovine Achilles tendon after subsequent heating.
(18) The drug was found to exhibit an ulcerostatic effect, to change the levels of collagen, noncollagen proteins, glycosaminoglycan fractions, DNA and RNA.
(19) Both enzymes are capable of catalyzing the refolding of thermally denatured type III collagen.
(20) Dissociated cerebral hemisphere cells from 4- to 7-day-old chick embryos were cultured either on a collagen or a polylysine substrate in a serum-containing medium.
Keratin
Definition:
(n.) A nitrogenous substance, or mixture of substances, containing sulphur in a loose state of combination, and forming the chemical basis of epidermal tissues, such as horn, hair, feathers, and the like. It is an insoluble substance, and, unlike elastin, is not dissolved even by gastric or pancreatic juice. By decomposition with sulphuric acid it yields leucin and tyrosin, as does albumin. Called also epidermose.
Example Sentences:
(1) The observed staining indicated that the epithelium of the external auditory meatus has a pattern of keratin expression typical of epidermis in general and the epithelium of the middle ear resembles simple columnar epithelia.
(2) A new method of staining the keratin filament matrix allowing a visualization of the filaments in cross section of hair fibres has been developed.
(3) The positive reaction for keratin and vimentin confirmed the presence of ectodermal and mesodermal elements respectively in the tumor.
(4) The mean gain in width of keratinized gingiva averaged 3.15 mm.
(5) The histological changes by light and electron microscopy in these patients demonstrates the metaplastic changes of the basal cell of the mucosa differentiating into mucous and keratin cells.
(6) These particular keratins that were found among others in basal cells could also be detected to a variable extent in metaplastic and dysplastic cervical lesions.
(7) Chemically isolated separate preparations of the non-aggregating protein-chondroitin-keratin sulphate (PCKS) fraction from the hyaline cartilage and hyaluronic acid (HUA) of the vitreous body and of the umbilicus were investigated by electron microscopy.
(8) In benign lesions both keratins were present, while in malignant ones only keratin No.
(9) The diagnosis was defined by immunohistochemical methods, which showed a positivity for keratin in the cells lining spaces with a vascular appearance.
(10) All of the cell lines expressed keratin intermediate filaments and two showed weak co-expression of vimentin.
(11) The expression of keratin and differentiation markers was identical to that of normal keratinocytes, suggesting that psoriatic epidermal differentiation is not truncated in vitro as has been postulated to be the case in vivo.
(12) In seven out of eight patients, the urothelium adjacent to the squamous cell metaplasia was also positive for keratin, indicating a direct transformation of the urothelium to squamous cell epithelium.
(13) Carcinomas fail to express suprabasal cell keratins and this is regulated at the transcriptional level.
(14) Lactobacillus strains of numerous species isolated from several animal sources exhibited cellular hydrophobicities that differed from those expected on the basis of their abilities to colonize the keratinizing stratified squamous epithelium in the mouse stomach.
(15) Furthermore the presence of keratin 17 in a CIN I, II, or III lesion may indicate progressive potential while its absence could be indicative of a regressive behavior.
(16) We did not observe two distinct types of cells with different morphology or components which could be held responsible for the production of two different types of keratin as have been described in other animals, but rather a uniformity of cell structures in each layer and only the so-called "smooth" type of keratin.
(17) The present study compares different post-embedding staining methods, including conventional and low-temperature embedding techniques, for demonstration of the keratin and vimentin cytoskeleton of epidermal cells, applying commercially available polyclonal and monoclonal antibodies.
(18) All cases so examined had positive results for vimentin and negative results for keratin.
(19) We have examined the keratin proteins in normal human oral mucosa from 6 different regions including hard palate, buccal mucosa, tongue, gingiva and floor of the mouth.
(20) Expression of keratins of high molecular weight was reduced to small foci of keratinization and scattered dyskeratotic cells.