Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isolated adrenal cells from Vitamin E-deficient and control rats were prepared by a trypsin digestion method. Cyclic adenosine 3',5'-monophosphate (cyclic AMP) formation was studied in response to adrenocorticotropin (ACTH) in the presence and absence of ascorbate by measuring the conversion of prelabeled adenosine 5'-triphosphate [14C]ATP to cyclic [14C]AMP. Ascorbate (0.5 mM) inhibited ACTH-induced cyclic [14C]AMP formation in adrenal cells isolated from Vitamin E-deficient rats but had no effect in the control cells. The inhibitory effect of ascorbate on ACTH-induced cyclic AMP formation in Vitamin E-deficient rats decreased as the concentration of ACTH increased. In Vitamin E-deficient rats ascorbate inhibited ACTH-induced cyclic [14C]AMP formation after 30 min of incubation. There was no further significant accumulation of cyclic [14C]AMP at 60 min or 120 min although in the absence of ascorbate cyclic [14C]AMP continued to be formed. The in vitro addition of alpha-tocopherol reduced the inhibition of ACTH-induced cyclic [14C]AMP formation by ascorbate in Vitamin E-deficient rats. These studies suggest that alpha-tocopherol and ascorbate may affect ACTH-induced cyclic AMP formation through interaction with the membrane-bound enzyme adenylate cyclase.
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PMID:Effect of ascorbic acid on ACTH-induced cyclic AMP formation and steroidogenesis in isolated adrenal cells of vitamin E-deficient rats. 16 1

The comet assay is a widely used biomonitoring tool for DNA damage. The most commonly used cells in human studies are lymphocytes. There is an urgent need to find an alternative target human cell that can be collected from normal subjects with minimal invasion. There are some reports of buccal cells, collected easily from the inside of the mouth, being used in studies of DNA damage and repair, and these were of interest. However, our preliminary studies following the published protocol showed that buccal cells sustained massive damage and disintegrated at the high pH [O. Ostling, K.J. Johanson. Microelectrophoretic study of radiation-induced DNA damages in individual mammalian cells. Biochem. Biophys. Res. Commun. 123 (1984) 291-298] used, but that at lower pH were extremely resistant to lysis, an essential step in the comet assay. Therefore, the aims of this study were to develop a protocol than enabled buccal cell lysis and DNA damage testing in the comet assay, and to use the model to evaluate the potential use of the buccal cell model in human biomonitoring and nutritional study. Specifically, we aimed to investigate intra- and inter-individual differences in buccal cell DNA damage (as strand breaks), the effect of in vitro exposure to both a standard oxidant challenge and antioxidant treatment, as well as in situ exposure to an antioxidant-rich beverage and supplementation-related effects using a carotenoid-rich food. Successful lysis was achieved using 0.25% trypsin for 30 min followed by proteinase K (1mg/ml) treatment for 60 min. When this procedure was performed on cells pre-embedded in agarose on a microscope slide, followed by electrophoresis (in 0.01 M NaOH, 1mM EDTA, pH 9.1, 18 min at 12 V), a satisfactory comet image was obtained, though inter-individual variation was quite wide. Pre-lysis exposure of cells to a standard oxidant challenge (induced by H2O2) increased DNA strand breaks in a dose related manner, and incubation of cells in Trolox (a water soluble Vitamin E analogue) conferred significant protection (P<0.05) against subsequent oxidant challenge. Exposure of buccal cell in situ (i.e. in the mouth) to antioxidant-rich green tea led to an acute decrease in basal DNA strand breaks. In a controlled human intervention trial, buccal cells from 14 subjects after 28 days' supplementation with a carotenoid-rich berry (Fructus barbarum L.) showed a small but statistically significant (P<0.05) decrease in DNA strand breaks. These data indicate that this buccal cell comet assay is a feasible and potentially useful alternative tool to the usual lymphocyte model in human biomonitoring and nutritional work.
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PMID:A buccal cell model comet assay: development and evaluation for human biomonitoring and nutritional studies. 1608 24

Present study was conducted to evaluate the role of a protein fraction (PI, protein isolate) of the herb, Phyllanthus niruri (P. niruri) against nimesulide-induced oxidative stress in vivo using a murine model. Mice were intraperitoneally treated with that at a dose of 5mg/kg body weight for 7 days before and separately 1-5 days after nimesulide (at a dose of 10mg/kg body weight for 7 days) administration to evaluate its preventive and curative role. Levels of reduced glutathione (GSH), antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), as well as thiobarbituric acid reactive substances (TBARS) were measured in the liver homogenates of all study groups. Pretreatment with isolated P. niruri protein fraction significantly enhanced nimesulide-induced reduced levels of antioxidant enzymes and GSH as well as reduced the enhanced level of lipid peroxidation. Post-treatment studies showed that the recovery after nimesulide induced oxidative stress was more rapid if PI was administered compared to the spontaneous recovery of liver. Histological studies also suggest that this protein fraction could prevent as well as cure liver from nimesulide induced oxidative stress. DPPH radical scavenging assay showed that it could scavenge free radicals. Its antioxidant property was compared with that of a known potent antioxidant, Vitamin E. Besides, the effect of a non-relevant protein, BSA, was also included in the study. Heat treatment and trypsin digestion destroyed the biological activity of this protein fraction. In conclusion, data obtained suggest that the P. niruri protein fraction may protect liver from nimesulide-induced oxidative stress probably via promotion of antioxidant defense.
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PMID:Herbal (Phyllanthus niruri) protein isolate protects liver from nimesulide induced oxidative stress. 1654 28