Bleomycin induced sensitivity to TRAIL/Apo-2L-mediated apoptosis in human seminomatous testicular cancer cells is correlated with upregulation of death receptors.

The most common solid tumor is testicular cancer among young men. Bleomycin is an antitumor antibiotic used for the therapy of testicular cancer. TRAIL is a proapoptotic cytokine that qualified as an apoptosis inducer in cancer cells. Killing cancer cells selectively via apoptosis induction is an encouraging therapeutic strategy in clinical settings. Combination of TRAIL with chemotherapeutics has been reported to enhance TRAIL-mediated apoptosis of different kinds of cancer cell lines. The molecular ground for sensitization of tumour cells to TRAIL by chemotherapeutics might involve upregulation of TRAIL-R1 (TR/1, DR4) and/or TRAIL-R2 (TR/2, DR5) receptors or activation of proapoptotic proteins including caspases. The curative potential of TRAIL to eradicate cancer cells selectively in testicular cancer has not been studied before. In this study, we investigated apoptotic effects of bleomycin, TRAIL, and their combined application in NTera-2 and NCCIT testicular cancer cell lines. We measured caspase 3 levels as an apoptosis indicator, and TRAIL receptor expressions using flow cytometry. Both NTera-2 and NCCIT cells were fairly resistant to TRAIL's apoptotic effect. Incubation of bleomycin alone caused a significant increase in caspase 3 activity in NCCIT. Combined incubation with bleomycin and TRAIL lead to elevated caspase 3 activity in Ntera-2. Exposure to 72 h of bleomycin increased TR/1, TR/2, and TR/3 cell-surface expressions in NTera-2. Elevation in TR/1 cell-surface expression was evident only at 24 h of bleomycin application in NCCIT. It can be concluded that TRAIL death receptor expressions in particular are increased in testicular cancer cells via bleomycin treatment, and TRAIL-induced apoptosis is initiated.

Use of a Y-tube conduit after facial nerve injury reduces collateral axonal branching at the lesion site but neither reduces polyinnervation of motor endplates nor improves functional recovery.

BACKGROUND: Despite increased understanding of peripheral nerve regeneration, functional recovery after surgical repair remains disappointing. A major contributing factor is the extensive collateral branching at the lesion site, which leads to inaccurate axonal navigation and aberrant reinnervation of targets. OBJECTIVE: To determine whether the Y tube reconstruction improved axonal regrowth and whether this was associated with improved function. METHODS: We used a Y-tube conduit with the aim of improving navigation of regenerating axons after facial nerve transection in rats. RESULTS: Retrograde labeling from the zygomatic and buccal branches showed a halving in the number of double-labeled facial motor neurons (15% vs 8%; P < .05) after Y tube reconstruction compared with facial-facial anastomosis coaptation. However, in both surgical groups, the proportion of polyinnervated motor endplates was similar (≈ 30%; P > .05), and video-based motion analysis of whisking revealed similarly poor function. CONCLUSION: Although Y-tube reconstruction decreases axonal branching at the lesion site and improves axonal navigation compared with facial-facial anastomosis coaptation, it fails to promote monoinnervation of motor endplates and confers no functional benefit.

Application of a new chemiluminescence method for the determination of glucose-6-phosphate dehydrogenase activity in healthy and enzyme-deficient individuals.

INTRODUCTION: A chemiluminescence (CL) technique, which determines the glucose-6-phosphate dehydrogenase (G-6-PD) activities in healthy, heterozygous, and completely enzyme-deficient individuals was applied. METHODS: CL intensities were detected for 4 h at 15-min intervals in each sample with or without addition of G-6-PD substrates into the reaction mixture. RESULTS: The results revealed an inverse correlation to the reference UV method (Zinkham method; r=-0.80). Furthermore, the CL assay was able to detect G-6-PD activities as low as 0.2 IU/gHb, which was not possible by the UV method. DISCUSSION: In conclusion, we believe that this method offers a new diagnostic tool for the detection of G-6-PD activities in enzyme-deficient individuals and, because of its increased sensitivity, makes it amenable for determining the effects of different pharmaceutical agents on G-6-PD activity in tissue or cell cultures.

Antioxidant effect of EGb 761 on hydrogen peroxide-induced lipoperoxidation of G-6-PD deficient erythrocytes.

In order to reduce the haemolytic susceptibility of glucose-6-phosphate dehydrogenase (G-6-PD) deficient erythrocytes, Ginkgo biloba extract (EGb 761) and vitamin E (vit E) were used as antioxidant agents and their effects compared. The erythrocyte suspensions from control and G-6-PD deficient patients were subjected to hydrogen peroxide (H2O2) incubation for 1 h. The produced thiobarbituric acid reactive substance (TBARS) levels measured as nmol/g Hb were compared with those of the erythrocytes administered 250 microg/mL EGb 761 or vit E previously or concomitantly with H2O2. Preincubation with EGb 761 reduced the TBARS levels from 317.14 +/- 25.27 to 160.09 +/- 21.97 nmol/g Hb in controls and from 348.24 +/- 7.79 to 205.60 +/- 14.22 nmol/g Hb in deficient erythrocytes. Concomitant application of EGb 761 with H2O2 resulted in similar but less reduction. The antioxidative effects of vitamin E were comparable to those of EGb 761. Contrary to the results obtained from oxidant conditions, the antioxidant characteristics of EGb 761 and vitamin E were not observed when they were applied directly to the erythrocytes without oxidative stress. The findings demonstrate that irrespective of administration time, EGb 761 significantly reduced TBARS levels in the erythrocytes of control and G-6-PD deficient patients subjected to oxidative stress.

Plasma and erythrocyte magnesium, manganese, zinc, and plasma calcium levels in G-6-PD-deficient and normal male children.

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is the most common human enzymopathy in the world. Trace elements are important for normal hematopoiesis and can play a role in acute hemolytic anemia induced by G-6-PD deficiency. For this purpose, we studied two groups consisting of 10 male children who are G-6-PD-deficient and 12 age-matched normal male children to compare plasma and erythrocyte magnesium, manganese, zinc, and plasma calcium levels between G-6-PD-deficient and normal children. All assays were performed under normal conditions free of any oxidative attack that may result in hemolytic crisis in G-6-PD-deficient subjects. All parameters in each group did not differ significantly except for erythrocyte G-6-PD activities. These data show that plasma and erythrocyte trace element contents of G-6-PD-deficient subjects do not differ in normal conditions.

Influences of different stress models on the antioxidant status and lipid peroxidation in rat erythrocytes.

The aim of this study was to investigate the influences of different stress models on the antioxidant status and lipid peroxidation (LPO) in erythrocytes of rats. Swiss-Albino female rats (3 months old) were used in this study. Rats were randomly divided into the following four groups; control group (C), cold stress group (CS), immobilization stress group (IS) and cold + immobilization stress group (CS + IS). Control group was kept in an animal laboratory (22 +/- 2 degrees C). Rats in CS group were placed in cold room (5 degrees C) for 15min/day for 15 days. Rats in IS group were immobilized for 180 min/day for 15 days. Rats in CS + IS group were exposed to both cold and immobilization stresses for 15 days. At the end of experimental periods, the activities of glucose-6-phosphate dehydrogenase (G-6-PD), Cu,Zn-superoxide dismutase (Cu,Zn-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), and concentration of reduced glutathione (GSH) were measured. LPO was determined by measuring the contents of thiobarbituric acid-reactive substances (TBARS). Cu,Zn-SOD activity and TBARS concentration were increased after cold and immobilization stresses, but CAT and GSH-Px activities and GSH levels were decreased. Immobilization stress decreased the activity of G-6-PD. The activities of G-6-PD, CAT and GSH-Px, and the level of GSH were lower in CS + IS group than in the control group. Cu,Zn-SOD activity and TBARS levels were increased in CS + IS group when compared with the control group. From these findings, three stress models are thought to cause oxidative stress.