Induction of apoptosis and NF-kappaB by quercetin in growing murine L1210 lymphocytic leukaemic cells potentiated by TNF-alpha.

Polyphenol quercetin induced apoptosis in proliferating murine L1210 lymphocytic cells. DNA damage, as well as apoptosis and withdrawal from the cell cycle were transient. The above mentioned death promoting activity of quercetin was enhanced by physiological concentrations of TNF-alpha.

Excess of glucocorticoids impairs whole-body antioxidant status in young rats. relation to the effect of dexamethasone in soleus muscle and spleen.

The action of glucocorticoids in high doses is catabolic, but not much is known about the accompanying effects on antioxidative capacity of the entire body. Animals were treated (or not) with dexamethasone (Dex) 2 mg/kg b.w.

Lipid peroxidation and antioxidant status in experimental diabetes.

Oxidative stress is currently suggested as a mechanism underlying diabetes. The present study was designed to evaluate the oxidative stress related parameters in streptozotocin-induced diabetes in rats using different complementary approaches: susceptibility to in vitro oxidation (lipid peroxidation induction in liver homogenate, red blood cells hemolysis), blood antioxidant status (total antioxidant capacity by two approaches), and plasma isoprostane measurement, a new marker of lipid peroxidation in vivo. We have shown that induced liver thiobarbituric acid reactive substances increased after 4 weeks of diabetes, in spite of increased liver vitamin E content.

Insulin action on skeletal muscle protein metabolism during catabolic states.

Insulin plays a major role in the regulation of skeletal muscle protein turnover but its mechanism of action is not fully understood, especially in vivo during catabolic states. These aspects are presently reviewed. Insulin inhibits the ATP-ubiquitin proteasome proteolytic pathway which is presumably the predominant pathway involved in the breakdown of muscle protein.

Involvement of the rapamycin-sensitive pathway in the insulin regulation of muscle protein synthesis in streptozotocin-diabetic rats.

Insulin resistance in 3-day streptozotocin (STZ)-treated rats was manifested by the lack of antiproteolytic action of insulin as well as by a reduction of its stimulatory effect on protein synthesis (-60% compared with the control group) in epitrochlearis muscle incubated in vitro. In the present study, we have investigated the diabetes-associated alterations in the insulin signalling cascade, especially the phosphatidylinositol-3 kinase (PI-3 kinase)/p70 S6 kinase (p70(S6K)) pathway, in rat skeletal muscle. LY 294002, a specific inhibitor of PI-3 kinase, markedly decreased the basal rate of protein synthesis and completely prevented insulin-mediated stimulation of this process both in control and diabetic rats.

Expression of bcl-2 and bax in TGF-beta 1-induced apoptosis of L1210 leukemic cells.

TGF-beta1 is a multifunctional regulatory peptide (25 kDa) inducing growth arrest and apoptosis in many normal and neoplastic cells. In the present study, the involvement of proapoptotic (bax) and antiapoptotic (bcl-2) genes in the molecular mechanism of TGF-beta1-induced apoptosis of L1210 leukemic cells was investigated. Bax transcript was measured using the RT-PCR method with GAPDH as a "housekeeping gene" control, whereas Bcl-2 protein was determined using flow cytometry (FITC-conjugated monoclonal anti-Bcl-2 antibody and FITC-conjugated mouse anti-IgG1 antibody as a negative control).

Phorbol ester (12-O-tetradecanoylphorbol 13-acetate) prevents ornithine decarboxylase inhibition and apoptosis and L1210 leukemic cells exposed to TGF-beta 1.

Previous studies have shown that growth suppression and apoptosis of leukemic cells exposed to TGF-beta 1 is associated with the inhibition of ornithine decarboxylase (ODC)--the key enzyme of polyamine pathway. The aim of the present study was to evaluate the influence of 12-O-tetradecanoylphorbol 13-acetate (TPA)--a potent ODC inducer on antiproliferative and apoptotic effects of TGF-beta 1 in L1210 leukemic cells. Cells were incubated in 2% FCS/RPMI-1640 medium, supplemented with TGF-beta 1 (2 ng/ml).

The effect of OA on proliferation and polyamine metabolism of K 562 leukemic cells and their responsiveness to natural killer cell activity.

Orotic acid (OA), a known promoter of carcinogenesis, significantly stimulated proliferation of K 562 leukemic cells even at as high a concentration as 0.1 mM. This effect was accompanied by a significant increase of the activity of two key enzymes of the polyamine pathway, i.

Effect of orotic acid on TGF-beta 1-induced growth inhibition of L1210 leukemic cells.

Unlabelled: Transforming growth factor-beta 1 (TGF-beta 1) exerted growth-inhibitory effect on L1210 leukemic cell line, manifested by the decrease in viable and increase in dead cells. The cell death evoked by TGF-beta 1 was both necrotic and apoptotic, quantified by the trypan blue exclusion method and apoptotic index, respectively. The induction of programmed cell death by TGF-beta 1 was confirmed by gel electrophoresis of DNA, where the characteristic 'DNA ladder' resulting from the internucleosomal DNA cleavage was visualized.

Involvement of polyamines in epidermal growth factor (EGF), transforming growth factor (TGF)-alpha and -beta 1 action on culture of L6 and fetal bovine myoblasts.

1. alpha-Difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase significantly abolished stimulation of protein synthesis evoked by EGF, TGF-alpha or -beta 1 in L6 and fetal bovine myoblasts. 2.

TGF-beta 1 inhibits polyamine biosynthesis in K 562 leukemic cells.

The present study proved that TGF-beta 1 significantly inhibited the growth of K 562 cells. The drop in cell numbers after 24 h incubation with increasing concentrations of TGF-beta 1 (0.01, 0.

Comparison of metabolic effects of EGF, TGF-alpha, and TGF-beta 1 in primary culture of fetal bovine myoblasts and rat L6 myoblasts.

1. Comparative studies of EGF, TGF-alpha, and TGF-beta 1 action on the synthesis of DNA and cellular proteins in rat L6 myogenic cells and fetal bovine myoblasts demonstrated considerable differences between particular growth factors, dependent on dose and target cells. 2.

Metabolic effect of orotic acid in calves.

Eight calves (males, Black and White crossbred with Holstein-Fresian) were fed milk and milk replacer without (control group) or with potassium orotate (3 mmol./l.) supplementation for 6 weeks after birth.

Metabolic effect of orotic acid in rat L6 myoblasts.

Orotic acid (OA) is an intermediate in the pyrimidine pathway. The main source of OA in the human and animal diet is bovine milk and its products. OA significantly inhibited the stimulation of protein synthesis by FCS derived growth factors in L6 myoblasts.

Diurnal changes in cortisol level, neutrophil number and lyzozyme activity in foals during the first 13 weeks of life and in their lactating mothers.

In the blood of 11 foals and their lactating mothers (Standardbred) diurnal changes in the cortisol level, neutrophil number and lysozyme activity were studied during the first 13 weeks of life. The investigations began when a foal reached 7 days of age and were repeated every two weeks till 13 weeks of age. Blood samples were taken from the jugular vein every 4 hours for one day.