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

Acute radiation injury leads to thymic involution, adrenal enlargement, leukopenia, thrombocytopenia, gastrointestinal ulceration, and impaired wound healing. The authors hypothesized that supplemental vitamin A would mitigate these adverse effects in rats exposed to acute whole-body radiation. This hypothesis was based on previous experiments in their laboratory that showed that supplemental vitamin A is thymotropic for normal rodents and lessens the thymic involution, lymphopenia, and adrenal enlargement that follows stress, trauma, and neoplasia, largely obviates the impaired wound healing induced by the radiomimetic drugs streptozotocin and cyclophosphamide, lessens the systemic response (thymic involution, adrenal enlargement, leukopenia, lymphocytopenia) to local radiation, and shifts the median lethal dose (LD50/30) following whole-body radiation to the right. To test their hypothesis, dorsal skin incisions and subcutaneous implantation of polyvinyl alcohol sponges were performed in anesthetized Sprague-Dawley rats at varying times following sham radiation or varying doses of whole-body radiation (175-850 rad). In each experiment, the control diet [which contains about 18,000 IU vit. A/kg chow (3 X the NRC RDA for normal rats)] was supplemented with 150,000 IU vit. A/kg diet beginning at, before, or after sham radiation and wounding or radiation and wounding. The supplemental vitamin A prevented the impaired wound healing and lessened the weight loss, leukopenia, thrombocytopenia, thymic involution, adrenal enlargement, decrease in splenic weight, and gastric ulceration of the radiated (750-850 rad) wounded rats. This was true whether the supplemental vitamin A was begun before (2 or 4 days) or after (1-2 hours to 4 days) radiation and wounding; the supplemental vitamin A was more effective when started before or up to 2 days after radiation and wounding. The authors believe that prevention of the impaired wound healing following radiation by supplemental vitamin A is due to its enhancing the early inflammatory reaction to wounding, including increasing the number of monocytes and macrophages at the wound site; possible effect on modulating collagenase activity; effect on epithelial cell (and possible mesenchymal cell) differentiation; stimulation of immune responsiveness; and lessening of the adverse effects of radiation.
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PMID:Supplemental vitamin A prevents the acute radiation-induced defect in wound healing. 638 75

Leukocytes are recruited from peripheral blood into milk as part of the inflammatory response to mastitis. However, excessive accumulation of inflammatory cells alters the quality of milk and the proteases produced by polymorphonuclear neutrophils (PMNs) and macrophages may lead to mammary tissue damage. To investigate PMN recruitment and the kinetics of their intracytoplasmic enzymes in inflammation, we generated mastitis in six cows by intramammary infusion of lipopolysaccharide (LPS). Clinical signs of acute mastitis were observed in all of the cows, and normal status was resumed by 316 h. Intracytoplasmic elastase, collagenase, and cathepsin activities were measured within live cells by flow cytometry in peripheral blood leukocytes and milk PMNs before and during the inflammatory process (at 10 time points between 4 and 316 h). The proportion of immature PMNs was appreciated by CD33 surface labeling measured in flow cytometry. Leukopenia was observed in the peripheral blood 4 h postinfusion, concomitant to an increase in somatic cell counts in milk. CD33(+) PMNs were preferentially recruited from the peripheral blood to milk. Enzymatic activities were detected in PMNs, lymphocytes, and monocytes at levels depending on the cell type, sample nature, and time of collection. Milk PMNs had lower enzymatic activities than peripheral blood PMNs. This study showed that milk PMNs recruited during LPS-induced experimental mastitis have an immature phenotype and significantly lower enzymatic activities than peripheral blood PMNs. This suggests that CD33, an adhesion molecule, may be involved in the egress from blood to milk and that the enzymatic contents of PMNs are partly used during this process.
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PMID:Enzymatic activities of bovine peripheral blood leukocytes and milk polymorphonuclear neutrophils during intramammary inflammation caused by lipopolysaccharide. 1209 78