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Biomedical subjects

Masami Yamada

Publications and source records attributed to Masami Yamada.

36 records · Page 2Linked to original sources
PubMed2004

Adsorptive granulocyte and monocyte apheresis versus prednisolone in patients with corticosteroid-dependent moderately severe ulcerative colitis.

BACKGROUND/AIM: Active ulcerative colitis (UC) is often associated with increased peripheral granulocytes and monocytes/macrophages which show activation behavior and prolonged survival time. Further, mucosal granulocyte level parallels intestinal inflammation and can predict UC relapse. Accordingly, our aim was to see if adsorptive granulocyte/monocyte apheresis (GMA) can promote remission and spare steroid in patients with steroid-dependent (SD) UC. METHODS: 69 SD patients, at the time of relapse, were randomly assigned to groups I (n = 46) and II (n = 23). The mean dose of prednisolone (PSL) was 12 mg/day/patient, CAI (clinical activity index) 9.2 in both groups. Group I patients were given up to 11 GMA sessions over 10 weeks with Adacolumn; in group II, the mean dose of PSL was increased to 30 mg/day/patient. RESULTS: At week 12, 83% of group I and 65% of group II patients were in remission, CAI in group I was 1.7 (p < 0.001) and in group II, 2.5 (p < 0.001). Further, during the 12 weeks of treatment, the cumulative amount of PSL received per patient was 1,157 mg in group I and 1,938 mg in group II (p = 0.001). CONCLUSIONS: GMA appeared to be an effective adjunct to standard drug therapy of moderately severe UC by promoting remission and sparing steroids.

Adolescent↗
PubMed2004

An ATP-dependent activity that releases RanGDP from NTF2.

The small GTPase Ran functions in several critical processes in eukaryotic cells including nuclear transport, nuclear envelope formation, and spindle formation. A RanGDP-binding protein, NTF2, facilitates translocation of RanGDP through the nuclear pore complex and also acts to stabilize RanGDP against nucleotide exchange. Here, we identify a novel activity that stimulates release of GDP from Ran in the presence of NTF2. Hydrolyzable ATP enhances the GDP dissociation activity, and this enhancement is inhibited by nonhydrolyzable ATP analogues. In contrast, neither hydrolyzable ATP nor nonhydrolyzable ATP analogues affect GDP dissociation from Ran catalyzed by recombinant RCC1 or inhibition of GDP dissociation from Ran by recombinant NTF2. The ATP-dependent RanGDP dissociation activity therefore has the properties of a RanGDP dissociation inhibitor (GDI) displacement factor (RanGDF) where the GDI is NTF2. A protein phosphatase inhibitor mixture stimulates the RanGDF activity, suggesting the activity is regulated by phosphorylation. We propose that the ATP-dependent NTF2 releasing factor may have a role in the RanGDP/GTP cycle.

Active Transport, Cell Nucleus↗
PubMed2004

Inhibitory effect of green tea catechins in combination with sucralfate on Helicobacter pylori infection in Mongolian gerbils.

BACKGROUND: The occurrence of antibiotic-resistant Helicobacter pylori has been reported. It is desirable to develop an effective method to prevent the occurrence of resistant strains of Helicobacter pylori. Green tea catechins (GTCs) have been reported to have an antibacterial effect. Therefore, the possibility of eradicating Helicobacter pylori by the oral administration of GTCs was investigated. METHODS: Solutions of GTCs and solutions of GTCs adsorbed to sucralfate (GTC-scf), at concentrations of 20 mg GTCs and/or 20 mg sucralfate/ml were prepared. Then 1 ml of the GTC-scf or the GTC solution was administered daily, for 10 days to Mongolian gerbils infected with Helicobacter pylori. Then the stomachs were extirpated and homogenized. The homogenate was spread on selective medium plates. After 5-day culture, colony-forming units (CFU) of Helicobacter pylori were counted. RESULTS: The CFU of Helicobacter pylori was significantly decreased by GTC-scf. CONCLUSIONS: GTC-scf may have a bactericidal effect on Helicobacter pylori infection.

Administration, Oral↗
PubMed2004

Correlation of serum soluble TNF-alpha receptors I and II levels with disease activity in patients with ulcerative colitis.

OBJECTIVES: TNF-alpha has a major role in inflammatory bowel disease via two receptors, p55 (RI) and p75 (RII) expressed on many cell types, in particular neutrophils and monocytes (GM). Upon activation of these leukocytes, RI and RII are shed into the medium and can neutralize TNF. Accordingly, soluble RI and RII (s-RI/RII) are believed to have potent antiinflammatory actions. Further, in active UC, GM are elevated with activation behavior and recently adsorptive GM apheresis (GMA) in patients with severe UC was associated with a dramatic efficacy. In this study, we investigated the effects of GMA on serum s-RI/RII. METHODS: Thirty-one patients with UC, clinical activity index (CAI) 11.1 were treated with GMA by using the Adacolumn. In the column, leukocytes which bear the FcgammaR and complement receptors adhere to the column apheresis carriers (neutrophils, monocytes, and a small fraction of lymphocytes). One GMA session was 60 min at 30 mL/min and each patient could receive up to 11 sessions over 8 wk. Serum s-RI/II were measured in the blood at the column inflow (peripheral blood, time 0 and 60 min) and outflow at 60 min. RESULTS: Serum s-RI/RII showed strong correlation with CAI, r = 0.849 (p < 0.001) and r = 0.867 (p < 0.001), respectively and were greater than when patients were in remission or the levels in controls (p < 0.001). s-RI/RII at the column outflow were higher compared with inflow (p < 0.05) suggesting that RI/RII were shed from leukocytes which adhere to the carriers. Similarly s-RI/RII were significantly increased in the peripheral blood at the end of the 60 min GMA session compared with time 0. After 11 GMA sessions, CAI fell to remission level in 26 of 31 patients accompanied by falls of s-RI/RII. CONCLUSIONS: The sources of s-RI/RII are believed to be activated monocytes and neutrophils with further release when these leukocytes adhere to the column carriers. s-RI/RII released during GMA should contribute to the clinical efficacy of this procedure.

Adolescent↗
PubMed2003

Leukocyte adsorptive apheresis for the treatment of active ulcerative colitis: a prospective, uncontrolled, pilot study.

BACKGROUND AND AIMS: Active ulcerative colitis (UC) is characterized by infiltration of activated granulocytes and monocytes/macrophages (GM) within the large bowel mucosa. GM are major sources of inflammatory cytokines, and in UC they are elevated with increased survival time. We investigated the possibility that reducing the level of these cells might promote remission of active UC. METHODS: Thirty-one patients with active corticosteroid refractory (refractory) UC, mean age of 42 years, duration of UC 6 years, clinical activity index (CAI) of 15, disease activity index (DAI) of 10, and 8 corticosteroid naive patients (naive), mean age of 36 years, duration of UC 2 years, CAI of 11, DAI of 8 were recruited. Each patient was treated with up to 11 cycles of granulocyte and monocyte adsorptive apheresis over 11 weeks by using a 335-mL capacity column filled with cellulose acetate beads that adsorb GM. RESULTS: At week 12, 81% of refractory (CAI, 3; P < 0.001 and DAI, 4; P < 0.001) and 88% of naive (CAI, 1; P = 0.012 and DAI, 3; P = 0.011) patients achieved remission. Early relapse was not a feature, and at 12 months, 26 of 33 patients had maintained their remission. The treatment was well tolerated, and no severe side effects were observed. CONCLUSIONS: The outcome of this study suggests that reduction of circulating granulocytes and monocytes results in alleviation of inflammation and promotes clinical remission in patients with severe active UC that has not responded to intensive corticosteroid treatment. These data suggest that formal controlled studies are warranted.

Adult↗
PubMed2003

Cellular requirements for CRM1 import and export.

We studied the cellular requirements for the translocation of CRM1 (exportin 1) between the nucleus and the cytoplasm. CRM1 import requires neither ATP, Ran, Ran-dependent GTP hydrolysis, nor a particular temperature. CRM1 and importin beta compete with each other during their import. Thus, CRM1 is able to enter the nucleus in a manner similar to importinbeta. In contrast, the in vivo export of CRM1 involves ATP-consuming step(s).

Active Transport, Cell Nucleus↗
PubMed2003

A multifunctional domain in human CRM1 (exportin 1) mediates RanBP3 binding and multimerization of human T-cell leukemia virus type 1 Rex protein.

Human CRM1 (hCRM1) functions in the Rex-mediated mRNA export of human T-cell leukemia virus type 1 (HTLV-1) as an export receptor and as an inducing factor for Rex multimerization on its cognate RNA. Although there are only 24 amino acid differences between hCRM1 and rat CRM1 (rCRM1), rCRM1 can hardly support Rex activity, suggesting a role for rCRM1 as a determinant restricting the host range of HTLV-1. Here, we used a series of mutants, which were generated by interchanging residues of these CRM1s, to examine the relationship of hCRM1 functions. The functions for Rex multimerization and binding to nuclear export signals are mapped to different amino acid residues, and these are separable, suggesting that CRM1 not only functions as an export receptor but also participates in the formation of the RNA export complex through higher-ordered interaction with Rex. The region for the interaction with RanBP3, comprising four residues (amino acids [aa] 411, 414, 474, and 481), and the region for Rex multimerization, including two residues (aa 411 and 414), form an overlapped domain. Our results provide the molecular basis underlying the species-specific ability of HTLV-1 to propagate in human cells.

Amino Acid Sequence↗
PubMed2003

Three cases of liver injury caused by Sennomotokounou, a Chinese dietary supplement for weight loss.

Dietary supplements have become very popular worldwide because they are believed to be safe with few side effects. Here, we report three cases of liver injury caused by Sennomotokounou, a Chinese dietary supplement for weight reduction. All patients developed acute hepatotoxicity and recovered spontaneously after withdrawal of dietary product. This product contains fenfluramine, n-nitroso-fenfluramine, and dried thyroid tissue powder. In Japan, the regulatory agency for drug and food safety received 120 reports of hepatotoxicity associated with Sennomotokounou between 2000 and 2002. Physicians should inquire about the use of dietary supplements whenever patients present with unexplained acute liver dysfunction.

Adult↗
PubMed2002

Treatment of common bile duct obstruction by pancreatic cancer using various stents: single-center experience.

PURPOSE: To compare the effectiveness of various means of stenting in patients with biliary obstruction caused by pancreatic cancer in a retrospective analysis. METHODS: Sixty-two patients with biliary obstruction due to unresectable pancreatic cancer underwent biliary stenting. On the basis of the findings obtained by percutaneous transhepatic cholangiography (10 patients) and endoscopic retrograde cholangiography (52 patients), the site of obstruction was distal to the hilar confluence, predominantly especially in the middle to lower third of the common bile duct. Polyurethane-covered Wallstents (9 mm in diameter) were inserted in 13 patients, while uncovered Wallstents (10 mm in diameter) were used in 10 patients and plastic stents (10 Fr and 12 Fr) were used in 39 patients. RESULTS: Stenting was successful in 34 patients (87.2%) treated with plastic stents and in 22 patients (95.7%) treated with Wallstents. Effective biliary drainage was achieved in 32 out of 34 patients (94.1%) treated with plastic stents and in 21 out of 22 patients (95.5%) treated with Wallstents. The cumulative patency rate was significantly higher for the uncovered and covered Wallstents compared to plastic stents, but was not significantly higher for covered than for uncovered Wallstents. Stent occlusion occurred in 23 patients (70%; all by clogging) from the plastic stent group, in two patients (22%; by tumor ingrowth) from the uncovered Wallstent group, and in one patient (9%; by clogging) from the covered Wallstent group. The survival rate showed no significant difference among the three stent groups. CONCLUSION: The Wallstent is effective for long-term palliation in patients with obstruction caused by pancreatic cancer invading the middle to lower part of the common bile duct. The covered Wallstent can prevent tumor ingrowth, a problem with the uncovered Wallstent. However, it may be necessary to take measures to prevent the migration or clogging of covered Wallstents.

Adult↗
PubMed2002

Effect of cytochrome P4502C19 genotypic differences on cure rates for gastroesophageal reflux disease by lansoprazole.

BACKGROUND AND OBJECTIVES: The acid-inhibitory effect of lansoprazole depends on differences in cytochrome P450 (CYP) 2C19 genotypes. We assessed whether therapeutic effects of lansoprazole on gastroesophageal reflux disease (GERD) depended on the CYP2C19 genotype status in relation to the grade of GERD. METHODS: A total of 65 patients with GERD (grades A-D) completed treatment with lansoprazole, by taking 30 mg orally once a day for 8 weeks. The CYP2C19 genotype status of patients was determined by polymerase chain reaction-restriction fragment length polymorphism analysis. Before and after treatment, esophageal endoscopy was performed. GERD was considered to be cured on the basis of endoscopic findings at the end of treatment. Plasma lansoprazole levels could be determined at 3 hours after the last 30-mg dose of lansoprazole in the 27 genotyped patients. RESULTS: Cure rates for GERD depended significantly on the CYP2C19 genotype status, as well as the grade of GERD before treatment. Cure rates in the homozygous extensive, heterozygous extensive, and poor metabolizer groups were 45.8%, 67.9%, and 84.6%, respectively. Cure rates in the groups with GERD grade A, grade B, and grade C or D were 85.0%, 60.0%, and 45.0%, respectively. The cure rate in patients with the homozygous extensive metabolizer genotype of CYP2C19 with a GERD grade of C or D was very low (16.7%). Plasma lansoprazole levels in patients with the homozygous extensive metabolizer genotype were the lowest of the 3 groups. CONCLUSIONS: CYP2C19 genotype status, as well as the grade of GERD before treatment, is one of the determinants for the success or failure of treatment of GERD with lansoprazole. The low cure rate in patients with the homozygous extensive metabolizer genotype appeared to be a result of these patients having the lowest plasma lansoprazole levels among the 3 genotype groups.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2002

The carboxy-terminal region of the human immunodeficiency virus type 1 protein Rev has multiple roles in mediating CRM1-related Rev functions.

The human immunodeficiency virus type 1 (HIV-1) regulatory protein, Rev, mediates the nuclear export of unspliced and singly spliced viral mRNAs by bridging viral RNA and export receptor human CRM1 (hCRM1). Ribonucleoprotein complex formation, including the oligomerization of Rev proteins on viral RNA, must occur to allow export. We show here that Rev-Rev interactions, which are a basis of complex formation, can be initiated without cellular factors and are subsequently enhanced by hCRM1-Ran-GTP. Furthermore, we reveal functions for the Rev carboxy-terminal (C-terminal) region, which is well conserved among many HIV-1 strains, and for which no function has been reported. This region is required for the efficient binding of Rev to hCRM1 and consequently for nuclear export, Rev-Rev dimerization, and full Rev transactivator activity. Consistent with these results, a HIV-1 proviral plasmid that expresses a C-terminally truncated Rev mutant protein produces smaller amounts of the p24 antigen than does a plasmid that possesses an intact rev gene. These results indicate the functional importance of the C-terminal region for full Rev activity, which leads to efficient HIV-1 replication.

Active Transport, Cell Nucleus↗
PubMed2002

Ulcerative colitis in monozygotic twin sisters.

We present a rare occurrence of woman monozygotic twins with ulcerative colitis (UC). A 21-year-old woman came to our hospital because of diarrhea, abdominal pain and hematochezia. We diagnosed this case as proctitis type UC by endoscopic and histological findings. Six months later, her twin sister developed total colitis type UC. Both twins had HLA-A24, B52, DR2, and DQ1 serological types, and had DRB1*1502 DNA type, previously shown to be associated with UC. This case report suggested an association of genetic factor together with environmental factors in the etiology for UC.

Adult↗
PubMedDate not supplied

Does a surgery for hepatocellular carcinoma with tumor thrombus highly occupying in the right atrium have significance? A case report and review of the literature.

Hepatocellular carcinoma (HCC) advancing to the right atrium (RA) through the hepatic vein has generally been regarded as a terminal lesion of carcinoma. However, because tumor thrombus (TT) in the RA may cause sudden death by heart failure or pulmonary embolism, it is a pathologic condition that needs emergency extraction. Our case was a 55-year-old male. The HCC had a main lesion in the anterior region of the hepatic right lobe, accompanying TT highly occupying the region from the middle hepatic vein and inferior vena cava to the RA. For this tumor, we conducted an extended right anterior segmentectomy and extraction of the TT in the RA under an extracorporeal circulation. He was discharged on the 28th day after surgery, and at present, when 12 months have passed since the surgery, survives without any sign of its recurrence. There have been eight HCC cases including our case, reported regarding the simultaneous resections of a main tumor and TT under cardiopulmonary bypass. Because two patients among this group of eight survived for more than two years, resection is recommended even for advanced HCC highly infiltrating to the RA.

Carcinoma, Hepatocellular↗