Browsing by Author "Kuzu, M"

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    Clinical significance of TT virus infection in children with chronic hepatitis B
    Kasirga, E; Sanlidag, T; Akçali, S; Keskin, S; Aktas, E; Karakoç, Z; Helvaci, M; Sözen, G; Kuzu, M
    Background: The pathogenic role of TT virus (TTV) is not clear in patients with chronic hepatitis B. The aims of the present study were to determine the frequency of TTV positivity in serum and saliva samples and the possible role of TTV in children with chronic hepatitis B. Methods: Sera and saliva from 29 healthy children and 25 children with chronic hepatitis B were tested for TTV-DNA by means of real-time polymerase chain reaction (PCR). Results: Fifty-two percent (13/25) of the serum samples and 32% (8/25) of the saliva samples were positive for TTV-DNA in children with chronic hepatitis B. In healthy non-transfused children, TTV-DNA was detected in 58% (17/29) of the serum samples and 41% (12/29) of the saliva samples. Six (46%) of 13 children with chronic hepatitis and 10 (59%) of 17 healthy children had TTV-DNA positivity both in serum and saliva samples. Two serum samples were negative for TTV-DNA while the saliva samples were positive for TTV-DNA in chronic hepatitis B and control groups. Mean age, sex, serum alanine aminotransferase levels, hepatitis B virus (HBV)-DNA values were similar in TTV-positive and -negative children with chronic hepatitis B. However, total histologic activity index (HAI), periportal necrosis and portal inflammation scores were significantly higher in children with HBV-DNA and TTV-DNA viremia (P = 0.013, P = 0.008, P = 0.015, respectively). Conclusions: Because total HAI, periportal necrosis and portal inflammation scores were higher in children with TTV coinfection, TTV infection may contribute to the progression of liver damage in children with chronic hepatitis B.
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    Efficacy of hepatitis B vaccination and interferon-α-2b combination therapy versus interferon-α-2b monotherapy in children with chronic hepatitis B
    Helvaci, M; Kizilgunesler, A; Kasirga, E; Ozbal, E; Kuzu, M; Sozen, G
    Background: Although interferon (IFN) has been approved in the treatment of chronic hepatitis B in children, it is effective only in 30-40% of patients. In some studies it has been suggested that therapeutic use of anti-hepatitis B virus (HBV) vaccine may be beneficial in patients with chronic hepatitis B. The aim of the present study was to compare the efficacy of hepatitis B vaccination and IFN-alpha-2b in combination and IFN-alpha-2b monotherapy in children with chronic hepatitis B. Methods: Fifty treatment-naive children with chronic hepatitis B infection were randomly assigned to receive either 5 million units/m(2) recombinant IFN-alpha-2b subcutaneously three times per week for 9 months, and pre-S2/S vaccine at the beginning and 4 and 24 weeks after initiation of IFN therapy (n = 25) or recombinant IFN-alpha-2b (5 million units/m(2) subcutaneously thrice weekly) alone for 9 months (n = 25). Children were followed for at least 6 months after the end of therapy. Results: There was no statistically significant difference in the mean alanine aminotransferase levels, histologic activity index and fibrosis scores between combination and IFN monotherapy groups at the end of the therapy and end of the follow-up period. When combination and monotherapy groups were compared, the mean HBV-DNA values were significantly reduced in combination group at the end of the therapy (P = 0.004), but no statistically significant difference was found at the end of the follow up. Sustained HBeAg seroconversion with clearance of HBV-DNA was obtained in 13 of 25 children (52%) treated with combination therapy, and in eight of 25 patients (32%) treated with IFN monotherapy (P = 0.251). Conclusion: Although the difference was statistically insignificant, the sustained response rates were better in the combination therapy group than in the monotherapy group. The potential benefit of combining IFN and hepatitis B vaccine should be investigated in further studies with different regimens of combination therapy. (C) 2004 Blackwell Publishing Asia Pty Ltd.
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    Inhibitory Effects of Some Flavonoids on Thioredoxin Reductase Purified from Chicken Liver
    Türkoglu, EA; Kuzu, M; Ayasan, T; Inci, H; Eratak, SV
    Thiorecioxin reductases (TrxRs) are selenocysteine-containing flavoenzymes that reduce Trxin NADPH-dependent manner. In the view of the direct vital role of TrxR in a wide range of biochemical and physiological processes, methods to inhibit this enzyme are clinically important. TrxR has recently emerged as a new candidate in anticancer drug investigations because of overexpression in tumorous cells. In this study, TrxR from chick liver was purified 94.6-fold with a yield of 4.86% and a specific activity of 0.19 EU/mg. K-M and V-max, values of TrxR for DINB were calculated as 0.9 mM and 0,03 EU/mL, respectively. Then, the effects of the flavonoicis hesperidin, naringenin, chlorogenic acid, ferulic acid, naringin, 3,4-dihydoxybenzoic acid, and ellagic acid on the enzyme activity were evaluated under in-vitro conditions. Ellagic acid showed the strongest inhibitory activity on TrxR with a IC50 value of 18 mu M, followed by naringenin and chlorogenic acid with IC50 values of 46.7 mu M and 75.8 mu M, respectively. Our results showed that flavonoids as natural products are potential inhibitors of TrxRs and the flavonoid content in animal diets may alter metabolic pathways by influencing TrxR activity.