Search results for "Oxidation."
showing 10 items of 1877 documents
Oxidative and Nitrosative Pattern in Circulating Leukocytes of Very Early/Early Hepatocellular Carcinoma Patients
2020
Background/aim In chronic liver disease, various immune cell subsets exert pro or anti-tumour effects by releasing reactive oxygen and nitrogen species (ROS, RNS). Here, we evaluated the oxidative and nitrosative pattern in peripheral blood leukocyte subpopulations of early hepatocellular carcinoma (HCC) patients compared with HCC-free cirrhotic patients. Materials and methods Venous blood samples from 18 HCC-free cirrhotic patients and 17 early stage HCC patients were collected to determine ROS, RNS and reduced glutathione levels in isolated leukocytes analyzed by flow cytometry. Results Intracellular levels of ROS and glutathione were higher in lymphocytes, monocytes, and neutrophils from…
Tumor blood flow: The principal modulator of oxidative and glycolytic metabolism, and of the metabolic micromilieu of human tumor xenograftsin vivo
1989
We have investigated therapeutically relevant pathophysiological parameters of human breast and lung cancer xenografts in nude rats. All lung cancers and one breast cancer exhibited rapid growth and high blood flow values paralleled by high metabolic rates. The tissue of these tumors was well oxygenated up to very advanced growth stages. Xenografts from other breast cancer cell lines grew much more slowly, were poorly perfused, and exhibited low metabolic rates. Here, tumor hypoxia and tissue acidosis were evident. These results indicate that significant differences in the metabolic micromilieu can be detected in human tumors; these are due to varying perfusion rates and may be partly respo…
The levels of quinone reductases, superoxide dismutase and glutathione-related enzymatic activities in diethylstilbestrol-induced carcinogenesis in t…
1990
The level of quinone oxidoreductases (microsomal and cytosolic DT-diaphorase, NADPH-cytochrome P450 reductase and NADH-cytochrome b5 reductase), superoxide dismutase and glutathione-related enzymatic activities in diethylstilbestrol (DES)-induced carcinogenesis in kidney from Syrian golden hamsters are presented. Animals that exhibited two different stages of DES-induced carcinogenesis in kidney--pre- and neoplastic lesions and tumorous lesions (after 6 and 8 months of continuous exposure to DES respectively)--were studied in comparison to kidneys from control animals. A dramatic decrease in microsomal and cytosolic DT-diaphorase activities (13.6 and 37.8% of controls), as well as in glutat…
Gender- and age-related distinctions for the in vivo prooxidant state in Fanconi anaemia patients.
2004
Abstract Some selected oxidative stress parameters were measured in 56 Fanconi anaemia (FA) patients (42 untransplanted and 14 transplanted), 54 FA heterozygotes (parents) and 173 controls. Untransplanted FA patients showed a highly significant increase in leukocyte 8-hydroxy-2’-deoxyguanosine (8-OHdG) (p = 0.00003) and a borderline increase (p = 0.076) in urinary levels of 8-OHdG vs. child controls. These increases were more pronounced in female FA patients (p = 0.00005 for leukocyte 8-OHdG, and p = 0.021 for urinary 8-OHdG). Female FA patients also displayed a highly significant excess of spontaneous chromosomal breaks vs. male patients (p = 0.00026), in the same female:male ratio (≅ 1.4)…
Redox state alteration modulates astrocyte glucuronidation.
2004
We have investigated the effects of mild oxidative conditions on drug-metabolizing enzyme activity in rat cultured astrocytes. These experimental conditions promoting an oxidative environment were obtained by short exposure to a low concentration of menadione (5 microM) for a short duration (15 min). This resulted in the rapid and transient production of reactive oxygen species (+130%), associated with a decrease in GSH cellular content (-24%), and an increase in total protein oxidation (+26%), but promoted neither PGE(2) nor NO production. This treatment induced a rapid and persistent decrease in astrocyte glucuronidation activities, which was totally prevented by N-acetyl-l-cysteine. Thes…
Effect of metal ion catalyzed oxidation of rifamycin SV on cell viability and metabolic performance of isolated rat hepatocytes.
1991
The effect of rifamycin SV on metabolic performance and cell viability was studied using isolated hepatocytes from fed, starved and glutathione (GSH) depleted rats. The relationships between GSH depletion, nutritional status of the cells, glucose metabolism, lactate dehydrogenase (LDH) leakage and malondialdehyde (MDA) production in the presence of rifamycin SV and transition metal ions was investigated. Glucose metabolism was impaired in isolated hepatocytes from both fed and starved animals, the effect is dependent on the rifamycin SV concentration and is enhanced by copper (II). Oxygen consumption by isolated hepatocytes from starved rats was also increased by copper (II) and a partial i…
Nitric oxide is involved in anoxic preconditioning neuroprotection in rat hippocampal slices.
1999
Sublethal anoxia/ischemia protects against subsequent damaging insults in intact brain or hippocampal slices. To help further understand mechanisms underlying anoxic/ischemic preconditioning, we tested three hypotheses which were that: (a) anoxic preconditioning (APC) improves electrical recovery in rat hippocampal slices; (b) anoxic preconditioning requires nitric oxide (NO); and (c) anoxic preconditioning blocks mitochondrial dysfunction that occurs following re-oxygenation after anoxia. Control hippocampal slices underwent a single 'test' anoxic insult. Experimental slices were preconditioned by 3 short anoxic insults prior to the 'test' insult. Evoked potentials (EPs), and NADH redox st…
Mandarin Juice Improves the Antioxidant Status of Hypercholesterolemic Children
2008
Background: Oxidative stress has been linked to such degenerative diseases as atherosclerosis, and it has been suggested that increased dietary intake of antioxidants may reduce its progression. Objective: To determine the effect of mandarin juice consumption on biomarkers related to oxidative stress in hypercholesterolemic children. Materials and Methods: The diet of 48 children with plasma cholesterol >200 mg/dL and low-density lipoprotein cholesterol >130 mg/dL was supplemented for 28 days with 500 mL/day of pure (100%) mandarin juice (Citrus clementina Hort. ex Tan.). The composition of the mandarin juice was analyzed, and its antioxidant antiradical activity was evaluated in vitro. Mal…
Fatty acid oxidation and related gene expression in heart depleted of carnitine by mildronate treatment in the rat.
2004
The metabolic and genic effects induced by a 20-fold lowering of carnitine content in the heart were studied in mildronate-treated rats. In the perfused heart, the proportion of palmitate taken up then oxidized was 5-10% lower, while the triacylglycerol (TAG) formation was 100% greater than in controls. The treatment was shown to increase the maximal capacity of heart homogenates to oxidize palmitate, the mRNA level of carnitine palmitoyltransferase I (CPT-I) isoforms, the specific activity of CPT-I in subsarcolemmal mitochondria and the total carnitine content of isolated mitochondria. Concomitantly, the increased mRNA expression of lipoprotein lipase, fatty acid translocase and enzymes of…
Hypertensive status and lipoprotein oxidation in an elderly population at high cardiovascular risk.
2008
BACKGROUND: In elderly individuals, hypertension is a main risk factor for cardiovascular disease and oxidative damage is increased. Our aim was to assess the relationship between the degree of in vivo low-density lipoprotein (oxLDL) oxidation and the hypertensive status in a elderly population at high cardiovascular risk. METHODS: Cross-sectional study with baseline data from the PREDIMED (PREvención con DIeta MEDiterránea) trial, an intervention study directed at testing the efficacy of the Mediterranean diet on the primary prevention of cardiovascular disease. Participants were 1,130 subjects at high cardiovascular risk aged 55-80. At baseline, in vivo circulating oxLDL was measured, and…