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Theodoros Vassilakopoulos

Publications and source records attributed to Theodoros Vassilakopoulos.

6 recordsLinked to original sources
PubMed2002

Antioxidants attenuate the plasma cytokine response to exercise in humans.

Exercise increases plasma TNF-alpha, IL-1beta, and IL-6, yet the stimuli and sources of TNF-alpha and IL-1beta remain largely unknown. We tested the role of oxidative stress and the potential contribution of monocytes in this cytokine (especially IL-1beta) response in previously untrained individuals. Six healthy nonathletes performed two 45-min bicycle exercise sessions at 70% of Vo(2 max) before and after a combination of antioxidants (vitamins E, A, and C for 60 days; allopurinol for 15 days; and N-acetylcysteine for 3 days). Blood was drawn at baseline, end-exercise, and 30 and 120 min postexercise. Plasma cytokines were determined by ELISA and monocyte intracellular cytokine level by flow cytometry. Before antioxidants, TNF-alpha increased by 60%, IL-1beta by threefold, and IL-6 by sixfold secondary to exercise (P < 0.05). After antioxidants, plasma IL-1beta became undetectable, the TNF-alpha response to exercise was abolished, and the IL-6 response was significantly blunted (P < 0.05). Exercise did not increase the percentage of monocytes producing the cytokines or their mean fluorescence intensity. We conclude that in untrained humans oxidative stress is a major stimulus for exercise-induced cytokine production and that monocytes play no role in this process.

Acetylcysteine↗
PubMed2002

Strenuous resistive breathing induces plasma cytokines: role of antioxidants and monocytes.

Inspiratory resistive breathing increases plasma cytokines, yet the stimulus (or stimuli) and source(s) remain unknown. We tested the role of reactive oxygen species as stimuli and of monocytes as sources of resistive breathing-induced cytokines. Six healthy subjects performed two resistive breathing sessions at 75% of maximum inspiratory pressure before and after a combination of antioxidants (vitamin E 200 mg, vitamin A 50,000 IU, and vitamin C 1,000 mg per day for 60 days, allopurinol 600 mg/day for 15 days, and N-acetylcysteine 2 g/day for 3 days before the second session). Blood was drawn before, at the end, and at 30 and 120 minutes after resistive breathing. Before antioxidants, plasma cytokine levels (determined by enzyme-linked immunosorbent assay) increased secondary to resistive breathing (tumor necrosis factor-alpha and interleukin [IL]-6 by twofold and IL-1beta by threefold). After antioxidants, plasma IL-1beta became undetectable. The tumor necrosis factor-alpha response to resistive breathing was abolished, and the IL-6 response was significantly blunted. Intracellular cytokine detection (by flow cytometry) showed no change in either the percentage of monocytes producing the cytokines or their mean fluorescence intensity both before and after antioxidants. We conclude that oxidative stress is a major stimulus for the resistive breathing-induced cytokine production and that monocytes play no role in this process.

Adult↗
PubMed2002

Production of interleukin-6 by skeletal myotubes: role of reactive oxygen species.

In the present study we have tested the ability of reactive oxygen species (ROS) to stimulate the production of interleukin (IL)- 6 from skeletal myocytes. Differentiated C2C12 murine skeletal muscle cells (myotubes) exposed to pyrogallol (PYR), xanthine/ xanthine-oxidase (X/XO), or H(2)O(2) for 24 h exhibited a concentration-dependent increase in IL-6 production. Unlike myotubes, incubation of myoblasts and endothelial cells with X/XO or PYR did not result in increased IL-6 release. In myotubes, superoxide dismutase and catalase blocked the ROS-induced IL-6 release. Exposure of myotubes to H(2)O(2) increased steady-state IL-6 mRNA levels, and pretreatment of myotubes with actinomycin D or cycloheximide abolished the ROS-induced IL-6 production. In addition, pretreatment of cells with N-acetyl-cysteine blocked tumor necrosis factor (TNF)-alpha-induced IL-6 release, suggesting that endogenously produced ROS participate in IL-6 production. Myotubes stimulated with H(2)O(2) exhibited increased I kappa B-alpha phosphorylation and degradation, and treatment of C2C12 with ROS-generating agents increased activator protein (AP)-1 and nuclear factor (NF)-kappa B-dependent promoter activity. Finally, preincubation of myotubes with the pharmacologic inhibitor of NF-kappa B, diethyldithiocarbamate, or transient transfection with an I kappa B-alpha mutant, inhibited the ROS-stimulated IL-6 release. In conclusion, ROS stimulate IL-6 production from skeletal myotubes in a manner that involves transcriptional activation of the IL-6 gene through an NF-kappa B-dependent pathway.

Animals↗
PubMedDate not supplied

Pegylated liposomal doxorubicin in the CHOP regimen for older patients with aggressive (stages III/IV) non-Hodgkin's lymphoma.

Pegylated liposomal doxorubicin is associated with a lower risk of cardiotoxocity than conventional formulations of doxorubicin, allowing the use of higher cumulative doses. In this Phase II study, 25 patients aged over 70 years (median 79, range 75-82 years) with aggressive non-Hodgkin's lymphoma (NHL) (International Prognostic Index (IPI) -2, 12 (48%); IPI-3, 10 (40%); IPI-4, 3 (12%)) received CHOP with pegylated liposomal doxorubicin. All completed 6 treatment cycles and were evaluable for efficacy and safety. A complete response was achieved in 13 (52%) patients and a partial response in 12 (48%) patients, which was maintained for at least 12 months. The median time to progression was 26 months (range 14->42) and median overall survival was 32 months (range 26-48). No Grades III/IV toxicity occurred; adverse events included neutropenia, anaemia, nausea and vomiting, diarrhoea and constipation in 16-29% of the cycles. Pegylated liposomal doxorubicin is an effective and well-tolerated component that may be substituted for doxorubicin in the CHOPC (cyclophosphanide, doxorubicin, vincristine, prednizolone) regimen for the treatment of aggressive NHL in elderly people.

Aged↗