Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the course of healing of experimental ulcer one could observe a distinct difference between a cornea, subjected to the action of glycerol and a control one. The damage to the chemical structure of collagenous fibers was much smaller than in the control. On the basis of the investigations performed one may conclude that glycerol, through dehydration of the corneal tissue and stimulation of mucopolysaccharide synthesis, suppresses the activity of collagenase. In polarized light this process was manifested by the double refraction phenomenon and in clinical observation--by an accelerated healing of ulcer.
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PMID:Effect of dehydration of the cornea with experimentally induced ulcer on collagenase activity. 18 91

The properties of collagen films crosslinked by physical and chemical techniques were compared to the properties of films crosslinked with glutaraldehyde (GTA). Physical techniques studied include exposure to short wave (254 nm) u.v. irradiation and severe dehydration. Chemical techniques studied include immersion of collagen films in aqueous solutions of cyanamide or GTA. Collagen films exposed to combinations of aqueous solutions of cyanamide and severe dehydration had moduli of elasticity, swelling ratios and resistance to bacterial collagenase similar to films crosslinked with GTA. Theoretical calculations based on amino acid composition indicate that approximately seven times as many amino acid residues are capable of forming crosslinks using cyanamide or severe dehydration procedures as compared to GTA crosslinking. In addition, using severe dehydration or cyanamide forms crosslinks involving both amino and carboxyl residues which may allow these procedures to act synergistically. Based on our studies this two-step procedure effectively crosslinks collagen-based biomaterials while the only by-product of this reaction is water-soluble urea. Preliminary biocompatibility studies suggest that this crosslinking procedure may allow for pronounced tissue ingrowth.
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PMID:Evaluation of collagen crosslinking techniques. 609 1

The technique selectively removes the fibrous component of the interdental septum. Mandibles were fixed, demineralized and incubated at 37 degrees C in 0.1 per cent bacterial collagenase. Samples were post-fixed in 2 per cent buffered osmium tetroxide for 24 h prior to dehydration in ascending grades of acetones. While in pure acetone, tissue was ultrasonicated at 80 kHz for 5 min and conventionally processed for scanning electron microscopy. Ultrasonication of tissue without prior collagenase digestion did not expose transalveolar fibres in their entirety. After 6 h exposure to collagenase followed by ultrasonication, bone matrix and osteocytes were removed exposing transalveolar fibres which passed through the interdental septum without interruption, becoming continuous with the periodontium of the adjacent tooth.
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PMID:A new technique for exposure of osteocytes and transalveolar fibres of the interdental septum in the mouse for scanning electron microscopy. 630 19

Cultured mammalian cells appeared to express specific particles on their surface, which could be detected by their ability to nucleate ice crystals (I-centers) in a newly developed, two-dimensional crystallization assay. Their expression required approximately 24 h independent of cell density, and metabolic energy, and the number and distribution of the I-centers were cell-type specific. Their characteristic ability to nucleate ice crystals was highly sensitive to dehydration, to hyaluronidase and phospholipase C, but not to a number of proteases such as trypsin, chymotrypsin, collagenase, and pronase. However, these proteases, especially pronase, were able to detach the I-centers from the cell surface, without destroying their ability to nucleate ice crystals. I-centers were specific products of live cells, located in relatively small numbers at the cell surface organized in a detachable, sheet-like structure. We propose to consider the ice nucleating ability of I-centers as an expression of their ability to influence the water structure in the surface of cells. Even though their biological function is not known at this time, as water-structuring centers they appear remarkable enough to warrant our attention.
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PMID:Water structuring centers of mammalian cell surfaces. 1224 43

This study probed the changes of keratocytes cultured under simulated microgravity. Keratocytes were isolated from rabbit corneas using collagenase digestion method. Cells were seeded in a 55-mL capacity high-aspect-ratio vessel (HARV) of rotary cell culture system (RCCS) at a density of 1 x 10(4) cells/mL. Dehydrated bovine acellular corneal stroma (5 x 5 x 1 mm, n = 30) was used as a carrier for keratocyte culture. Rotational speed was set at 15, 20, and 30 rpm in the first, second, and third week of culture, respectively. Histological evaluation showed that keratocytes in simulated microgravity culture grew into carriers, but those under conventional gravity grew on the surface of carriers. Scanning electron microscopic evaluation showed that after 19 days in culture, keratocytes on the carriers were spherical and spread in the spaces among the collagen fibers. Cells were dendritic or spindle shaped, and they developed many foot processes linked with surrounding cells. The absorbance values of the simulated microgravity group were significantly higher (P < 0.01) than that of the conventional group from 10 to 19 days of culture. The RCCS obviously enhanced the proliferation of rabbit keratocytes and facilitated the cells' growth into or on the dehydrated bovine acellular corneal stroma. Cells showed more natural morphology.
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PMID:Morphological characteristics and proliferation of keratocytes cultured under simulated microgravity. 1772

The state of collagen molecules in the fibres of tail tendon, skin and demineralized bone has been investigated in situ using differential scanning calorimetry (DSC). Hydroxyproline analysis and tissue digestion with bacterial collagenase and trypsin were used to confirm that the common cause of all the DSC endotherms was collagen denaturation. This occurred within a narrow temperature range in tendons, but over a wide temperature range in demineralized bone and old skin and demonstrated that in tendon and demineralized bone at least the same type I collagen molecule exists in different thermal states. Hypothesizing that this might be caused by different degrees of confinement within the fibre lattice, experiments were performed to measure the effect of changing the lattice dimensions by extracting the collagen into dilute solution with pepsin, swelling the lattice in acetic acid, and contracting the lattice by dehydration. A theoretical analysis was undertaken to predict the effect of dehydration. Results were consistent with the hypothesis, demonstrating that collagen molecules within the natural fibres of bone and old skin are located at different intermolecular spacings, revealing differences between molecules in the magnitude of either the attractive or repulsive forces controlling their separation. One potential cause of such variation is known differences in covalent cross-linking.
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PMID:Thermal stabilization of collagen in skin and decalcified bone. 2126 66