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Featured researches published by Yuriko Koga.


The American Journal of Gastroenterology | 2003

A real-time quantitative polymerase chain reaction method for hepatitis B virus in patients with chronic hepatitis B treated with lamivudine

Tatsuya Ide; Ryukichi Kumashiro; Yuriko Koga; Eisuke Tanaka; Teruko Hino; Akiko Hisamochi; Shiro Murashima; Kei Ogata; Kazuo Tanaka; Reiichiro Kuwahara; Michio Sata

OBJECTIVES:During treatment of chronic hepatitis B with lamivudine, changes in the level of hepatitis B virus (HBV) DNA were investigated using a real-time polymerase chain reaction (PCR) method with a detection limit of 1.7 log copies/ml (50 copies/ml) to clarify its clinical significance, particularly the association between HBV DNA levels and the emergence of tyrosine-methionine-aspartate-aspartate (YMDD) mutants.METHODS:Twenty-four patients who had received lamivudine therapy for >1 yr were studied. HBV DNA levels were determined using transcription-mediated amplification for sera with >3.7 log genome equivalents/ml, the Roche Monitor kit for sera with ≥2.6 log copies/ml, and real-time PCR for sera with < 2.6 log copies/ml (the detection limit was 1.7 log copies/ml). Patients were classified into three groups according to the minimal HBV DNA level attained during lamivudine therapy: the <1.7 log copies/ml group (eight patients), the 1.7–2.5 log copies/ml group (five patients), and the ≥2.6 log copies/ml group (11 patients).RESULTS:Pretreatment HBV DNA levels were significantly lower in the <1.7 copies/ml group than in the other two groups (p < 0.05). Neither the emergence of YMDD mutants nor a virological breakthrough of serum HBV DNA was observed in any of the eight patients in the <1.7 copies/ml group. In contrast, in the 1.7–2.5 copies/ml and ≥2.6 copies/ml groups, virological breakthroughs resulting from the emergence of YMDD mutants were observed in two of five patients and in all 11 patients, respectively (p < 0.001). Virological breakthroughs were observed at a mean of 49.6 ± 18.4 wk in 11 the patients in the ≥2.6 copies/ml group and at wk 107 and 115 in two patients in the 1.7–2.5 copies/ml group.CONCLUSION:The real-time PCR method is useful for predicting the emergence of YMDD mutants and the estimated time of their emergence.


Journal of Medical Virology | 2000

Effect of interferon treatment on serum 2',5'-oligoadenylate synthetase levels in hepatitis C-infected patients.

Shiro Murashima; Ryukichi Kumashiro; Tatsuya Ide; Ichiro Miyajima; Teruko Hino; Yuriko Koga; Kunihide Ishii; Takato Ueno; Shotaro Sakisaka; Michio Sata

Interferon (IFN) is widely used for patients with hepatitis C. Less than half of treated patients respond to IFN therapy, however, and increased resistance to IFN is particularly observed in genotype 1b patients. Recently, genotype 1b patients with the wild type sequence in the NS5A gene were shown to be resistant to therapy, suggesting that the NS5A protein may be involved to IFN resistance. Thus, we investigated the serum 2′,5′‐oligoadenylate synthetase (2′,5′‐OAS) levels before and during IFN treatment. In addition, other biochemical markers and NS5A mutations were also examined in 30 HCV genotype 1b‐positive patients. Before IFN treatment, 2′,5′‐OAS activity in sera was significantly lower in wild type patients than in mutant type patients. All patients were subsequently enrolled in IFN therapy, and 2′,5′‐OAS activity was elevated both in wild and mutant type patients, irrespective of the number of mutations in NS5A. Logistic regression analysis revealed that clearance of serum HCV RNA was independently related to the pretreatment viral load and NS5A mutations, but not to serum 2′,5′‐OAS activity. We concluded that the NS5A protein, that is associated with the outcome of IFN therapy, affects the kinetics of IFN‐induced molecules, such as 2′,5′‐OAS. 2′,5′‐OAS activity does not, however, seem to be related to long‐term virological response to IFN therapy. J. Med. Virol. 62:185–190, 2000.


Hepatology Research | 2001

Transcription-mediated amplification is more useful in the follow-up of patients with chronic hepatitis B treated with lamivudine

Tatsuya Ide; Ryukichi Kumashiro; Teruko Hino; Shiroh Murashima; Kei Ogata; Yuriko Koga; Michio Sata

Changes in the HBV DNA level during the treatment of patients with chronic hepatitis B with lamivudine were investigated by the transcription-mediated amplification (TMA) assay. Twenty-four patients treated with lamivudine (males:female= 20:4, age: 44.0+/-9.0 years, chronic hepatitis: 14, cirrhosis: 7, cirrhosis with hepatocellular carcinoma: 3) were investigated. The dosage of lamivudine was 75 mg/day in 3, 100 mg/day in 8, and 150 mg/day in 13 patients, and the administration period was 48+/-16 weeks (24-79 weeks). Sixteen patients were HBe antigen-positive before treatment, and the HBV DNA level was 7.4+/-1.2 (4.0- more than 8.7) LGE/ml. The HBV DNA level was measured every 1-6 months by the TMA assay and the branched DNA signal amplification technology (b-DNA assay). Serum HBV DNA disappeared in all patients by the b-DNA during the treatment period, while six patients had persistent HBV DNA by the TMA. The time of HBV DNA disappearance by the TMA in 18 patients was 2-5 months after initiation of treatment. The disappearance rate of HBV DNA was 3/8 (38%) in patients whose HBV DNA level before treatment was 8.0 LGE/ml or higher, 7/8 (88%) in those with 7-7.9 LGE/ml, and 8/8 (100%) in those with 6.9 LGE/ml or lower, showing that disappearance of HBV DNA became difficult when the HBV DNA level before treatment was high (P<0.01). In six patients, the HBV DNA level disappeared once, then increased thereafter. The present findings suggested that these increases in the HBV DNA level were due to an increase of YMDD mutant in three of these six patients, and due to a decrease in the dosage in two patients. In treatment with lamivudine, the TMA assay is more useful for understanding the changes in the HBV DNA level than b-DNA assay.


Hepatology Research | 2003

Association of troglitazone-induced liver injury with mutation of the cytochrome P450 2C19 gene

Ryukichi Kumashiro; Takahiro Kubota; Yuriko Koga; Masatoshi Tanaka; Chizuko Inada; Nobuhide Kusaba; Hiroshi Yoshida; Akiko Hisamochi; Tatsuya Ide; Yuko Tomita; Naoko Masumoto; Kyuichi Tanikawa; Tatsuji Iga; Michio Sata

An anti-diabetic agent, troglitazone, was withdrawn from the market because of its association with liver injury. However, the mechanism of the injury has not been elucidated. We examined, retrospectively, the frequency of the polymorphisms of the cytochrome P450 (CYP) 2C19 and 2D6 genes in eight patients with type 2 diabetes who had troglitazone-induced liver injury and 31 subjects who tolerated troglitazone well. Polymorphisms of CYP 2C19 and 2D6 genes were analyzed by polymerase chain reaction using peripheral white blood cells. The incidence of mutations was compared with known population data for the Japanese. Homozygous or compound heterozygous mutations in CYP 2C19 alleles were found in four of the eight (50.0%) patients with troglitazone-induced liver injury. This rate was significantly higher than that in patients without liver injury (four of 31, 12.9%). The frequency of P450 2D6 mutations was the same in both groups. In conclusion, troglitazone-induced liver injury occurred more frequently in subjects with the CYP 2C19 mutations in Japanese patients.


Journal of Gastroenterology | 1999

Erythropoietic protoporphyria with fatal liver failure.

Akiko Ishibashi; Riko Ogata; Shotaro Sakisaka; Ryukichi Kumashiro; Yuriko Koga; Keiichi Mitsuyama; Ryoko Kuromatsu; Yasuyo Uchimura; Hiroyasu Ijyuin; Kumi Tanaka; Tadashi Iwao; Kunihide Ishii; Michio Sata; Yoshiko Inoue; Yasuko Kin; Kotaro Oizumi; Hidemi Nishida; Tsutomu Imaizumi; Kyuichi Tanikawa

Abstract: A 33-year-old woman with a history of photosensitivity, persistent abdominal pain, and liver dysfunction was admitted to our department because of abdominal pain and progression of liver dysfunction. On admission, levels of protoporphyrin and coproporphyrin within erythrocytes were markedly increased. Autofluorescent erythrocytes were also detected, leading to a diagnosis of erythropoietic protoporphyria. A liver biopsy specimen revealed cirrhosis with dark brown granules filling hepatocytes, bile canaliculi, and bile ductules. Transfusion of washed erythrocytes, hemodialysis, and administration of cholestyramine and beta-carotene transiently improved levels of porphyrins and liver function. The patient died of rupture of esophageal varices followed by multiple organ failure. However, the treatments were believed to have extended survival.


Digestive Diseases and Sciences | 2004

Adefovir Dipivoxil as a Treatment for Hepatic Failure Caused by Lamivudine-Resistant HBV Strains

Reiichiro Kuwahara; Ryukichi Kumashiro; Hiroto Inoue; Ryo Tanabe; Eisuke Tanaka; Teruko Hino; Tatsuya Ide; Yuriko Koga; Michio Sata

Hepatitis B virus (HBV) infection is a serious worldwide problem because it is one of the major causes of cirrhosis and hepatocellular carcinoma in endemic areas. The number of people with chronic HBV infection is 350 million globally (1). Until recently, the therapeutic option for chronic HBV infection has been limited to interferon. Seroconversion from hepatitis B e antigen (HBeAg) to anti-hepatitis B e antibody (anti-HBe) occurs in up to about 40% of patients treated with interferon monotherapy (2–4). Recently, lamivudine, a nucleoside analogue, has become the main therapeutic option for chronic HBV infection. Some clinical trials showed that lamivudine suppressed HBV replication effectively and induced histological improvement (5–7). However, the prolonged therapy with lamivudine has been associated with the emergence of drug-resistant viruses with the mutations in the polymerase gene coding for the YMDD (tyrosine, methionine, aspartate, aspartate) motif (8, 9). The lamivudine-resistant HBV strains have been observed in 14 to 32% of patients undergoing a 1-year treatment regimen of 100 mg daily (6, 7). Several new nucleoside analogues are now under development. Adefovir dipivoxil, a prodrug of the acyclic deoxyadenosine monophosphate analogue adefovir, displays potent antiviral activity against HBV (10, 11) and an in vitro study demonstrated the antiviral activity to be against both wild-type and lamivudine-resistant strains of


Alcoholism: Clinical and Experimental Research | 2003

Severe alcoholic hepatitis successfully treated by leukocytapheresis: a case report.

Yoshiyasu Tsuji; Ryukichi Kumashiro; Kunihide Ishii; Teruko Arinaga; Yoshihiro Sakamoto; Ryo Tanabe; Kei Ogata; Yuriko Koga; Tatsuya Ide; Naofumi Ono; Eisuke Tanaka; Hirohiko Abe; Michio Sata

BACKGROUND The prognosis of severe alcoholic hepatitis is poor, and there is no established method for a cure. METHODS A 34-year-old man was admitted to Kurume University Hospital because of severe liver dysfunction due to excess alcohol intake. He was treated with prednisolone and two sessions of granulocyte and monocyte adsorption apheresis (GCAP) using an Adacolumn, which removes leukocytes--especially granulocytes and monocytes--from the peripheral blood. We evaluated the changes in the serum levels of interleukin-6, interleukin-8, tumor necrosis factor-alpha, and soluble intercellular adhesion molecule-1, as well as the conventional liver tests and peripheral white blood cell count. RESULTS Prednisolone was effective in the short term but resulted in an increase in C-reactive protein (CRP), peripheral leukocytes, and serum total bilirubin. GCAP performed on the 34th and 41st hospital days produced decreases in the white blood cell count, total bilirubin, and intercellular adhesion molecule-1. The patient survived, despite the expected poor prognosis on admission. CONCLUSIONS GCAP is recommended as a potential therapeutic option for severe alcoholic hepatitis.


Hepatology Research | 2002

Short term and two-step interferon therapy for chronic hepatitis C patients with low HCV RNA levels.

Tatsuya Ide; Ryukichi Kumashiro; Teruko Hino; Shiro Murashima; Kei Ogata; Yuriko Koga; Michio Sata

Objective: Chronic hepatitis C patients with low HCV RNA levels were treated with short term therapy and for patients in whom the virus was not eliminated in this short therapy, we designed a two-step IFN therapy. Subjects: There were 31 patients with chronic hepatitis C whose HCV RNA level before IFN therapy was <1.0 Meq/ml or 100 kcopies/ml. The HCV serotypes were serotype 1 in nine patients, serotype 2 in 21 and mixed type in one. A 9--10 MU per day of natural IFN was administered daily for 2 weeks, then three times weekly for 8 weeks (the first therapy), then the therapy was ended. For patients in whom the virus was not eliminated, an additional IFN therapy was administered during the decreasing phase of HCV RNA (second therapy). The historical control group consisted of 57 patients who fulfilled the above criteria and underwent IFN therapy for 24 weeks. Complete responders were defined as patients in whom HCV RNA was not detected in their serum for at least 6 months after the end of treatment. Results: Nineteen (61%) of 31 patients who completed the first therapy showed complete response to the first therapy. Eight patients underwent the second therapy and the complete response rates were 0/4 and 2/4 (50%) in the serotype 1 and 2 groups, respectively. The overall complete response rate was 44% (4/9) in the serotype 1 group, 76% (16/21) in the serotype 2 group and 100% (1/1) in the mixed type. The complete response rate in the historical control group was 70% (40/57), showing no difference in efficacy. However, the IFN dosage was significantly lower in the patients than in the control group (P<0.001). Conclusions: In patients with low HCV RNA levels and serotype 2, short term therapy is sufficiently effective. Furthermore, 50% of the complete response was obtained by an additional second therapy. This therapy design showed high efficacy and was cost-effective in these patients.


Intervirology | 2003

Subclones of Drug-Resistant Hepatitis B Virus Mutants and the Outcome of Breakthrough Hepatitis in Patients Treated with Lamivudine

Ryukichi Kumashiro; Reiichiro Kuwahara; Tatsuya Ide; Yuriko Koga; Teruko Arinaga; Akiko Hisamochi; Kei Ogata; Kazuo Tanaka; Michio Sata

Breakthroughs during lamivudine therapy were assessed according to hepatitis flares and mutational polymorphism of hepatitis B virus (HBV) infecting patients. Of 42 patients with chronic hepatitis B and positive for hepatitis B e antigen in serum, 13 (30%) harbored HBV mutants with lamivudine resistance after a mean duration of 29 months on lamivudine. The virological breakthrough occurred 14.5 months after the start of lamivudine treatment, and all the patients with it developed breakthrough hepatitis 3 months later. The clinical course of breakthrough hepatitis was self-limited except in one patient who had already developed cirrhosis at the baseline. One year after breakthrough hepatitis, serum ALT, albumin, prothrombin time and platelet counts were maintained well on conventional treatments without resorting to interferon. Major HBV mutants during breakthrough hepatitis were those with M552I in the YMDD motif of viral DNA polymerase/reverse transcriptase in 7 patients (54%), M552I/L528M in 4 patients (31%) and M552V/L528M in 2 patients (15%). There were no patients in whom mutations at nucleotide 529 occurred including the 2 who later developed hepatocellular carcinoma. There was no clear relationship between distinct mutational patterns and clinical courses. Further studies are needed for making out the effects of lamivudine-resistant mutants on clinical outcomes, taking into considerations genotypes of HBV.


Journal of Gastroenterology | 2005

Clinical course of patients with chronic hepatitis B with viral breakthrough during long-term lamivudine treatment

Tatsuya Ide; Ryukichi Kumashiro; Reiichiro Kuwahara; Hiroyuki Koga; Yuriko Koga; Teruko Hino; Kazuo Tanaka; Akiko Hisamochi; Kei Ogata; Michio Sata

BackgroundWe evaluated the clinical course of patients with chronic hepatitis B who showed viral breakthrough during long-term lamivudine therapy.MethodsWe initially studied 141 patients treated with lamivudine for 1 year or more, and 49 patients who showed viral breakthrough were the subjects of this study. Their mean lamivudine administration period was 2.3 ± 0.9 years.ResultsAfter viral breakthrough, breakthrough hepatitis occurred in 47 patients (95.9%), but did not occur in the other 2 (4.1%). Four of the 47 patients with breakthrough hepatitis were observed without further treatment, and the alanine transferase (ALT) level was normalized in 2 of them but fluctuated in the other 2. Breakthrough hepatitis was treated by injection of glycyrrhizin or ursodeoxycholic acid administration in 36 of the remaining 43 patients, and by antiviral drug administration in the other 7 (entecavir in 2 patients, adefovir in 2, and interferon in 3). The ALT level was normalized in 5 of the 36 patients treated with glycyrrhizin or ursodeoxycholic acid, but persistently fluctuated in the other 31. In those with normalized ALT after the occurrence of breakthrough hepatitis, the peak ALT level at that point was significantly lower (86 ± 47 IU/l) than that in the patients without normalization (206 ± 167 IU/l).ConclusionsThese results showed that there were a few patients who did not develop breakthrough hepatitis after showing viral breakthrough, and some who showed normalization of the ALT level after the occurrence of breakthrough hepatitis, but in many patients, ALT continuously fluctuated.

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