Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adherent human mesangial cells (HMC) were unable to phagocytose serum-treated zymosan (STZ), nevertheless this stimulus (1 mg/ml) induced a marked immediate increase of H2O2 and O2- release at a rate of 3.15 +/- 0.35 and 3.40 +/- 0.12 nmol/10(6) HMC/hr, respectively. Zymosan alone resulted in no release of either H2O2 or O2-. Phorbol myristate acetate (PMA, 2 X 10(-6) M) had only marginal effects on HMC leading to the generation of 0.273 +/- 0.014 nmol O2-/10(6) HMC/hr. After a lag period, human recombinant tumor necrosis factor-alpha (TNF-alpha) and human recombinant interleukin 1-alpha IL-1 alpha) both induced significant O2- production measured as SOD inhibitable reduction of cytochrome c, 5 X 10(-5) M, by adherent HMC for up to five hours, the maximum rates being 3.04 +/- 0.08 and 3.2 +/- 0.08 nmol/10(6) HMC/hr for IL-1 alpha and TNF-alpha, respectively. Significant O2- release was detectable at 0.625 ng/ml (37 pM) IL-1 alpha or 1 ng/ml (59 pM) TNF-alpha (P less than 0.05). Catalase inhibitable H2O2 production was also induced by IL-1 alpha and TNF-alpha in a dose dependent manner. Using scopoletin (40 nM) and 1 microM peroxidase we fluorimetrically measured 1.73 +/- 0.14 and 1.49 +/- 0.19 nmol H2O2/10(6) HMC/hr induced by IL-1 alpha (25 ng/ml) and TNF-alpha (20 ng/ml). Finally, we ascertained the type of radical species produced by HMC stimulated by cytokines employing ESR-spin-trapping with DMPO.2+ These results demonstrated that O2- was the primary radical species formed.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Interleukin 1-alpha and tumor necrosis factor-alpha induce oxygen radical production in mesangial cells. 240 88

Single-walled carbon nanotubes (SWCNT), nano-cylinders with an extremely small diameter (1-2 nm) and high aspect ratio, have unique physico-chemical, electronic and mechanical properties and may exhibit unusual interactions with cells and tissues, thus necessitating studies of their toxicity and health effects. Manufactured SWCNT usually contain significant amounts of iron that may act as a catalyst of oxidative stress. Because macrophages are the primary responders to different particles that initiate and propagate inflammatory reactions and oxidative stress, we utilized two types of SWCNT: (1) iron-rich (non-purified) SWCNT (26 wt.% of iron) and (2) iron-stripped (purified) SWCNT (0.23 wt.% of iron) to study their interactions with RAW 264.7 macrophages. Ultrasonication resulted in predominantly well-dispersed and separated SWCNT strands as evidenced by scanning electron microscopy. Neither purified nor non-purified SWCNT were able to generate intracellular production of superoxide radicals or nitric oxide in RAW 264.7 macrophages as documented by flow-cytometry and fluorescence microscopy. SWCNT with different iron content displayed different redox activity in a cell-free model system as revealed by EPR-detectable formation of ascorbate radicals resulting from ascorbate oxidation. In the presence of zymosan-stimulated RAW 264.7 macrophages, non-purified iron-rich SWCNT were more effective in generating hydroxyl radicals (documented by EPR spin-trapping with 5,5-dimethyl-1-pyrroline-N-oxide, DMPO) than purified SWCNT. Similarly, EPR spin-trapping experiments in the presence of zymosan-stimulated RAW 264.7 macrophages showed that non-purified SWCNT more effectively converted superoxide radicals generated by xanthine oxidase/xanthine into hydroxyl radicals as compared to purified SWCNT. Iron-rich SWCNT caused significant loss of intracellular low molecular weight thiols (GSH) and accumulation of lipid hydroperoxides in both zymosan-and PMA-stimulated RAW 264.7 macrophages. Catalase was able to partially protect macrophages against SWCNT induced elevation of biomarkers of oxidative stress (enhancement of lipid peroxidation and GSH depletion). Thus, the presence of iron in SWCNT may be important in determining redox-dependent responses of macrophages.
 ...
PMID:Direct and indirect effects of single walled carbon nanotubes on RAW 264.7 macrophages: role of iron. 1652 36