Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was conducted to examine the effects of mastitis and stage of lactation on plasminogen activator (PA) activity in milk somatic cells. An assay system, which measures the plasmin-mediated hydrolysis of the chromogenic substrate D-valyl-leucyl-lysine p-nitroanilide, was used to assess PA activity present within milk somatic cells. Milk cell associated PA activity was increased (P < 0.05) by 50% in the presence of fibrin fragments. This suggests that milk somatic cells contain tissue PA which, unlike urokinase PA, is preferentially activated in the presence of fibrin fragments. An increase of the milk somatic cell count from < 5 x 10(4) to > 10(6) cells/ml resulted in an 8-fold increase in PA activity per cell. Elevated levels of PA activity were associated with milk somatic cells isolated from mastitic quarters obtained from cows in early (< 4 months in lactation) or late lactation (> 8 months in lactation). We conclude that PA activity is increased during severe mastitic inflammation. Although the physiological function of this enzyme is as yet unclear, we propose that it may be involved in the conversion of plasminogen to plasmin, contributing to the higher levels of plasmin occurring in milk isolated from mastitic quarters.
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PMID:Effect of mastitis on plasminogen activator activity of milk somatic cells. 145 31

The antiproteolytic activity of selected proteinase inhibitors was studied in mastitic bovine milk and urokinase-activated normal milk using a caseolytic agar diffusion assay. The inhibition profiles of mastitic milk and urokinase-activated milk were compared with those of purified proteinases. The proteinase inhibition profile of mastitic milk did not resemble that of any of the pure proteinases, indicating a mixed type of proteinase system in mastitic milk. The trypanocidals diminazene (equivalent to Berenil) and pentamidine (equivalent to Lomidine), together with aprotinin (Trasylol), showed most promise when considering possible applications in mastitis to break up the proteolytic cascade within the inflamed udder.
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PMID:Inhibition of the proteinase activity in mastitic milk. 753 66

Staphylococcus aureus commonly causes bovine mastitis, but bovine strains, unlike human isolates of S. aureus, do not produce the bacterial plasminogen activator, staphylokinase. By use of bovine mammary epithelial and myoepithelial cell lines, it was found that bovine S. aureus M60 and its culture filtrates induce a 3- to 10-fold increase in urokinase-type plasminogen activator activity in mammary cell-conditioned media and cellular lysates. Furthermore, transcytosis of S. aureus M60 across a mammary epithelial cell monolayer was significantly enhanced by the addition of bovine plasminogen and inhibited by aprotinin. These findings provide evidence that S. aureus M60 can trigger superactivation of host plasminogen activator production and may then utilize the plasminogen activator-plasmin(ogen) system to facilitate tissue invasion without producing staphylokinase.
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PMID:Staphylococcus aureus stimulates urokinase-type plasminogen activator expression by bovine mammary cells. 939 82

Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection. The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection. Induction of matrix metalloproteinase-9, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue. These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation.
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PMID:Escherichia coli induces apoptosis and proliferation of mammary cells. 1152 34