Biomedical subjects

S Takemura

Publications and source records attributed to S Takemura.

At least 19 recordsLinked to original sources

PubMed2001

Influence of previous interferon therapy on recurrence after resection of hepatitis c virus-related hepatocellular carcinoma.

Interferon (IFN) therapy decreases the incidence of hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV). One hundred and fifty-nine consecutive patients who underwent liver resection for HCV-related HCC were studied. In 17 (group 1) of the 159 patients, HCC was detected during or after IFN therapy. The incidences of recurrence after surgery in the group 1 patients and the other 142 patients (group 2) were compared. Eight patients had a complete response to IFN, 4 had a partial response, and 5 had no response. The proportion of patients without HCV viremia was significantly higher in the group 1 patients (P < 0.0001). The tumor-free survival rate was significantly higher in the group 1 patients (P = 0.0010). By multivariate analysis of various risk factors for recurrence, no previous IFN was a significant independent risk factor for recurrence (risk ratio = 6.336; 95%CI, 1.512 - 26.50). The patients with HCC who underwent IFN therapy previously are good candidates for liver resection because recurrence after the operation was rarely observed.

Aged↗

PubMed2000

Cell-cell interactions in synovitis. Interactions between T cells and B cells in rheumatoid arthritis.

In rheumatoid arthritis, T cells and B cells participate in the immune responses evolving in the synovial lesions. Interaction between T cells and B cells is probably antigen specific because complex microstructures typical of secondary lymphoid organs are generated. Differences between patients in forming follicles with germinal centers, T-cell-B-cell aggregates without germinal center reactions, or loosely organized T-cell-B-cell infiltrates might reflect the presence of different antigens or a heterogeneity in host response patterns to immune injury. Tertiary lymphoid microstructures in the rheumatoid lesions can enhance the sensitivity of antigen recognition, optimize the collaboration of immunoregulatory and effector cells, and support the interaction between the tissue site and the aberrant immune response. The molecular basis of lymphoid organogenesis studied in gene-targeted mice will provide clues to why the synovium is a preferred site for tertiary lymphoid tissue. B cells have a critical role in lymphoid organogenesis. Their contribution to synovial inflammation extends beyond antibody secretion and includes the activation and regulation of effector T cells.

Animals↗

PubMed2000

Functional Fv fragment of an antibody specific for CD28: Fv-mediated co-stimulation of T cells.

The most predominant co-stimulation pathway, which is critical for T cell activation and proliferation, is the CD28-B7 pathway. The anti-CD28 monoclonal antibody (mAb) also provides a co-stimulatory signal to T cells. In order to construct a functional Fv fragment (complex of VH and VL domains) of anti-CD28 antibody using a bacterial expression system, cDNA encoding the variable regions of immunoglobulin from 15E8 hybridoma cells was cloned and expressed in Escherichia coli. The Fv fragment was obtained as a soluble protein from the periplasmic fraction and showed a binding pattern similar to parental IgG. The Fv fragment induced proliferation of peripheral blood mononuclear cells in the presence of anti-CD3 or anti-CD2 mAb and enhanced anti-tumor activity of anti-MUC1x(anti)-CD3 bispecific antibody when tested with lymphokine-activated killer cells with T cell phenotype. Thus, the anti-CD28 Fv fragment will be promising not only for the study of co-stimulation, but also for cancer immunotherapy.

Amino Acid Sequence↗

PubMed2000

The thoracoscopic approach for internal mammary nodes in breast cancer.

BACKGROUND: This pilot study was conducted to estimate the use of the thoracoscopic surgery as a new approach for the internal mammary nodes (IMN) in breast cancer. PATIENTS AND METHODS: For this study, 21 women with breast cancer who underwent the approach for nodes IMN were enrolled. All the women had suspicious IMN metastasis and no distant metastasis. RESULTS: Thoracoscopic IMN dissection was performed safely for 20 of the women, with an average operative time of 44 min. One woman was excluded from the procedure because of pleural adhesion. The patients were restricted from walking for 1.3 days because of chest drainage, but no patients had severe complication or chest wall deformity after the operation. Six patients had positive IMN outcomes. After surgery, 10 of the 20 patients had a lower tumor node metastases (TNM) staging. Two patients who tested positive for IMN and three who tested negative experienced a relapse, but none had pleural dissemination in a median follow-up period of 24 months. CONCLUSION: Thoracoscopic surgery may be useful in managing patients with IMN.

Adult↗

PubMed2000

Post-ischemic intraportal adenosine administration protects against reperfusion injury of canine liver.

Although adenosine has been postulated to inhibit ischemia-reperfusion injury in various tissues, its in vivo cytoprotective mechanism is not fully known. The aim of this study was to determine the effect of intraportally infused adenosine on reperfusion injury in the canine liver. Two h ischemia and reperfusion of the liver were induced in beagle dogs by clamping the portal triad. Either adenosine or saline was infused in the portal vein after reperfusion for 60 min. Levels of serum aspartate aminotransferase and alanine aminotransferase and the survival of animals were examined. Hepatic levels of protein carbonyls and glutathione were also measured, as markers of oxidative stress. One h after reperfusion, the liver was perfused with nitroblue tetrazolium and the formation of formazan was observed to evaluate superoxide formation. Twenty-four h after reperfusion, 100% of animals in the adenosine group and 33% of animals in the control group survived. Adenosine significantly decreased the reperfusion-induced increase in serum levels of aspartate aminotransferase and alanine aminotransferase. Adenosine also suppressed the formation of protein carbonyls and the decrease in glutathione levels. Histologically, neutrophil infiltration, superoxide formation, and apoptosis were decreased by adenosine. These results suggest that intraportally infused adenosine attenuates reperfusion injury of the liver, presumably by suppressing the activation of neutrophils and oxidative stress.

Adenosine↗

PubMed2000

Isolation and chemical--structural identification of a novel aromatic amine mutagen in an ozonized solution of m-phenylenediamine.

The mutagenicity of a m-phenylenediamine (m-PD) solution was markedly enhanced by oxidation with ozone. The ethyl acetate extracts from a m-PD solution ozonized at pH 10.7 were fractionated by normal-phase and reversed-phase column chromatography to isolate mutagens by monitoring mutagenic activities on Salmonella typhimurium TA98 in the presence of a mammalian metabolic activation system (S9 mix). From fraction 5-3-2, which exhibited the strongest mutagenicity (308000 revertants/mg), a major mutagenic compound was isolated. On the basis of the high-resolution EI-mass, (1)H NMR and (13)C NMR spectral, and X-ray crystallography data, the structure of this compound was determined to be 2-amino-5-[(3-aminophenyl)amino]-4-[(3-aminophenyl)imino]-2, 5-cyclohexadien-1-one (PDT-1), which is a novel compound. PDT-1 is a newly identified frame-shift type mutagen, inducing 65400 revertants and 295000 revertants of S. typhimurium TA98 and YG1024 per micromole, respectively, in the presence of S9 mix. When a m-PD solution was oxidized with 1 or 2 mol of ozone at pH 4.0, 7.0, and 10.7, the contribution of PDT-1 to the mutagenicity of ethyl acetate extracts from the ozonized m-PD solution was 5-23%.

Animals↗

PubMed2000

Functional construction of the anti-mucin core protein (MUC1) antibody MUSE11 variable regions in a bacterial expression system.

A bacterial expression system for the variable region fragments (Fvs) of the anti-MUC1 tumor antigen antibody MUSE11 has been constructed. The Fv fragment showed binding specificity toward TFK-1 cells, with slightly reduced affinity compared to its parent IgG. The single-chain Fv fragment was arranged in two orders, VH-linker-VL and VL-linker-VH. However, linking the regions with a flexible peptide linker (GGGGS)(3) or with a shorter linker (GGGGS) led to a dramatic decrease in the biological activity toward the target antigen in both arrangements, suggesting that the MUSE11 antibody loses its activity when the domains are linked with polypeptide linkers. These results indicate that the variable region domains of the anti-MUC1 antibody MUSE11 have specificity only in the Fv form, and that linking the domains strongly reduces the association with its target antigen. Gel filtration analysis indicates that the scFv has a dimeric structure, suggesting that the inactivation of MUSE11 scFv is due to unfavorable intermolecular associations of the scFv chains. To our knowledge, this is the first report of a significant reduction in affinity caused by linking the variable domains in both arrangements, i.e., VH-VL and VL-VH.

Animals↗

PubMed2000

Construction of a diabody (small recombinant bispecific antibody) using a refolding system.

Diabodies are the recombinant bispecific antibodies (BsAbs), constructed from heterogeneous single-chain antibodies. Usually, diabodies have been prepared from bacterial periplasmic fraction using a co-expression vector (i.e. genes encoding two chains were tandemly located under the same promoter). Some diabodies, however, cannot be expressed as a soluble material owing to inclusion body formation, which limits the utilization of diabodies in various fields. Here we report an improved method for the construction of diabodies using a refolding system. As a model, a bispecific diabody binding to adenocarcinoma-associated antigen MUC1 and to CD3 on T cells was studied. One chain consisted of a VH specific for MUC1 linked to a VL specific for CD3 with a short polypeptide linker (GGGGS). The second was composed of a VL specific for MUC1 linked to a VH specific for CD3. The two hetero scFvs were independently obtained from intracellular insoluble fractions of Escherichia coli, purified, mixed stoichiometrically (at an equivalent molar ratio of 1:1) and refolded. The refolded two hetero scFv has a hetero-dimeric structure, with complete specificity for both target cells [i.e. MUC1 positive cells and CD3 positive lymphokine-activated killer cells with a T cell phenotype (T-LAK)]. Evaluation of the in vitro efficacy of T-LAK with the diabody by growth inhibition assay of cancer cells demonstrated maximum growth inhibition of cancer cells to reach approximately 98% at an effector:target ratio (E:T ratio) of 10, almost identical with that with anti-MUC1xanti-CD3 chemically synthesized BsAbs (c-BsAbs). This is the first report of the construction of a diabody using a refolding system.

Antibodies, Bispecific↗

PubMed2000

Pharmacokinetics and in vivo gene transfer of plasmid DNA complexed with mannosylated poly(L-lysine) in mice.

To achieve mannose receptor-mediated, cell-specific, in vivo gene transfer by intravenous injection of plasmid DNA, mannosylated poly(L-lysine) (Man-PLL) was synthesized as a carrier molecule, and mixed with a plasmid DNA encoding chloramphenicol acetyltransferase (CAT) gene to form DNA/Man-PLL complex. The particle size and zeta potential of DNA/Man-PLL (prepared at 1:0.7 on a weight basis) were determined to be 220 nm and +12 mV, respectively. The pharmacokinetics of the DNA/Man-PLL complex was assessed in mice using 32P-labeled DNA ([32P]DNA). After intravenous injection of [32P]DNA/Man-PLL, the radioactivity in plasma fell rapidly and was recovered mainly in the liver nonparenchymal cells. The amount in the liver reached more than 80% of the dose. Radioactivity observed in kidney, lung, and spleen was very low compared to that in the liver. Then, the in vivo gene expression after intravenous injection of DNA/Man-PLL was examined by a CAT assay. Highest CAT activity was detected in the liver, but no activity was detected in the lung, kidney, and spleen. These results clearly indicate that a cell-specific gene delivery system can be developed by regulating the biodistribution of DNA/carrier complex through the control of its physicochemical properties.

Animals↗

PubMed2000

[CD16+ CD56- indolent, NK cell-lineage granular lymphocyte proliferative disorder with autoimmune hemolytic anemia].

A 64-year-old man was given a diagnosis of CD16+ CD56- natural killer cell-lineage granular lymphocyte proliferative disorder (NK-GLPD) with Coombs-negative autoimmune hemolytic anemia (AIHA). Two courses of 1,000 mg intravenous methylprednisolone for 3 days were transiently effective for both AIHA and NK-GLPD. On the recurrence of AIHA, NK-GLPD also re-appeared. The same treatment was effective in controlling both diseases again. This was a rare case of NK-GLPD combined with autoimmune disease.

Anemia, Hemolytic, Autoimmune↗

PubMed2000

[Factors related to smoking behavior of nursing students revealed by a cohort study].

PURPOSE: Through a cohort study, changes in smoking behavior of nursing students and the factors related to their smoking behavior were examined. METHOD: Research through anonymous questionnaires concerning smoking behavior was conducted on nursing students in the first to third grades (as of 1997) at two vocational schools of nursing located in the Tokyo Metropolitan area. The same research was conducted in the same manner on the same subjects the following year. RESULTS: The smoking prevalence among nursing students of the first and second grades as of 1997 had increased by 10% in one year, and that of nursing students of the third grade (to graduate in 1998) had increased by 5%. The average degree of nicotine dependence of the subjects, who replied that they smoked every day in both surveys, increased from 4.25 to 5.00. As to factors related to smoking behavior, the smoking behavior of friends largely influenced that of the nursing students. CONCLUSIONS: Education to prevent nursing students from smoking should be started as soon as possible at vocational schools of nursing, because the research showed that more than 70% of the smokers had actually thought of quitting and that their views toward smoking influenced later smoking behavior.

Adolescent↗

PubMed2000

[Treatment outcome in elderly patients with aggressive non-Hodgkin's lymphoma].

Seventy-one patients aged 61-84 years with previously untreated aggressive non-Hodgkin's lymphoma were treated with a doxorubicin-containing regimen and evaluated retrospectively. The patients comprised 49 men and 22 women with a median age of 68 years. The median observation period was 544 days. Histological examination revealed 17 cases of diffuse small cleaved, 11 cases of diffuse mixed, 40 cases of diffuse large, and 3 cases of immunoblastic lymphoma, classified according to the International Working Formulation. When the patients were divided according to the age-adjusted international index, group A (61-64 years; n = 21) comprised 5 low (L)-, 4 low-intermediate (LI)-, 7 high-intermediate (HI)-, and 5 high (H)-risk patients. The corresponding numbers in group B (> or = 65 years; n = 50) were 14, 12, 16, and 8, respectively. The overall three-year survival rate was 50%, being 78% in group A and 36% in group B (P = 0.02), and 77% for L + LI patients and 34% for HI + H patients (P = 0.003). The respective three-year survival rates for L + LI and HI + H patients were 100% and 67% in group A, and 68% and 16% in group B. HI + H patients in group B showed shorter survival than L + LI patients in group B (P = 0.002) and HI + H patients in group A (P = 0.03). The cause of death in most group B HI + H patients was lymphoma, although the dose intensity of doxorubicin, cyclophosphamide and vincristine did not differ significantly from that in the other groups. Thus, HI + H patients aged 65 and over had an essentially poor prognosis.

Aged↗

PubMed1999

Isoforms of cytochrome P450 on organic nitrate-derived nitric oxide release in human heart vessels.

Glutathione S-transferases and the cytochrome P450 system have been proposed for the vascular biotransformation systems in the metabolic activation of organic nitrates. The present study was designed to elucidate the role of human cytochrome P450 isoforms on nitric oxide formation from organic nitrates using lymphoblast microsomes transfected with human CYP isoforms cDNA. CYP3A4-transfected microsomes had the most effective potential of nitric oxide formation from isosorbide dinitrate. Anti-CYP3A2 antibody (which cross-reacts with CYP3A4) or ketoconazole (an inhibitor of the CYP3A superfamily) inhibited nitric oxide formation from isosorbide dinitrate in rat heart microsomes. Immunohistochemistry of human heart also showed intense bindings of CYP3A4 antibody in the endothelium of the endocardium and coronary vessels. These results suggest that the CYP3A4-NADPH-cytochrome P450 reductase system specifically participates in nitric oxide formation from isosorbide dinitrate.

Animals↗

PubMed1999

SEA-scFv as a bifunctional antibody: construction of a bacterial expression system and its functional analysis.

A SEA-antibody single chain Fv (SEA-scFv) fusion protein was produced by bacterial expression system in this study. SEA-scFv has both staphylococcal enterotoxin A (SEA) effects and antibody activity directed at the epithelial mucin core protein MUC1, a cancer associated antigen. It was expressed mostly in the cytoplasm as an insoluble form. The gene product was solubilized by guanidine hydrochloride, refolded by conventional dilution method, and purified using metal-chelating chromatography. The resulting SEA-scFv fusion protein preparation was found to react with MUC1 and MHC class II antigens and had the ability to enhance cytotoxicity of lymphokine activated killer cells with a T cell phenotype against a human bile duct carcinoma cell line, TFK-1, expressing MUC1. This genetically engineered SEA-scFv fusion protein promises to be an important reagent for cancer immunotherapy.

Antibodies, Bispecific↗

PubMed1999

Preoperative detection of occult enterovesical fistulas in patients with Crohn's disease: efficacy of oral or rectal administration of indocyanine green solution.

OBJECTIVES: Nonhazardous enteral administration of indocyanine green solution was performed to detect enterovesical occult microfistulas in patients with Crohn's disease before the fistulas had become readily apparent. METHODS: A total of 12 patients with Crohn's disease who were suspected from their clinical manifestations of having enterovesical fistulas underwent study. For detection of the fistulas after oral or rectal administration of the indocyanine green solution, urine was collected and examined using a colorimeter to check for contamination with indocyanine green. The effectiveness of the indocyanine green test and conventional x-ray study was compared. RESULTS: The indocyanine green test was positive after either oral or rectal administration in 11 of the 12 patients, providing a rate of accurate diagnosis of 92 percent (11/12 patients). In contrast, the rate of accurate diagnosis using the x-ray study was only 17 percent (2/12 patients). Furthermore, in eight patients with occult fistulas, accurate diagnosis could be made in none using the x-ray study, whereas all showed positive results with use of the indocyanine green test. CONCLUSIONS: The ability to diagnose obscure fistulas using the indocyanine green test was 92 percent. This indocyanine green test was highly diagnostic, whereas conventional examinations are often complicated and much less diagnostic.

Administration, Oral↗

PubMed1999

Differential regulation of intracellular Ca2+ signalling induced by high K+ and endothelin-1 in single smooth muscle cells of intact canine basilar artery: detection by means of confocal laser microscopy.

Changes in intracellular calcium concentration ([Ca2+]i) in smooth muscle cells play the key role in regulation of vascular smooth muscle tone and pathogenesis of cerebral vasospasm. In this study, we adopted the confocal laser microscopy to detect the fluorescence signals arising from the individual smooth muscle cells of canine basilar artery. Ring preparations were made, loaded with fluo-3 and changes in fluorescence induced by high K+ and endothelin-1 (ET-1) were measured by confocal laser microscopy. In some unstimulated smooth muscle cells Ca2+ waves arising from discrete region of the cell propagated to the whole cell with a velocity of approximately 10 microm/s. High K+ (80 mmol/L) induced a rapid rise in [Ca2+]i, the peak level being consistently reached approximately 10 s after stimulation. In contrast, the time to peak level of [Ca2+]i induced by ET-1 (0.3 micromol/L) varied widely between 13 and 26 s among individual cells, an indication that the extent of nonuniform coordination of increases in [Ca2+]i in individual cells may be partly responsible for the different time courses of tension development of vascular smooth muscle in response to the vasoactive stimulants. The increase in [Ca2+]i induced by ET-1 was transient but a pronounced and sustained contraction developed further in response to ET-1. Thus ET-1 has a biological property as a potential candidate to elicit cerebral vasospasm. Confocal laser microscopy could be a useful tool to measure the changes in [Ca2+]i in individual smooth muscle cells of cerebral artery.

Animals↗

PubMed1999

Hepatic cytochrome P450 is directly inactivated by nitric oxide, not by inflammatory cytokines, in the early phase of endotoxemia.

BACKGROUND/AIMS: Although the activity of the liver in metabolizing and eliminating various drugs decreases in endotoxemia, the mechanism remains to be elucidated. The generation of nitric oxide by the inducible type of nitric oxide synthase increases in endotoxemia. Nitric oxide readily reacts with heme proteins such as cytochrome P450 that metabolize various compounds, including steroids and eicosanoids. The purpose of this study was to determine the effect of nitric oxide on the function of hepatic cytochrome P450 in endotoxemic rats. METHODS: To determine the dynamic aspects of nitric oxide metabolism, hepatic levels of the inducible type of nitric oxide synthase and heme-iron nitrosyl complexes, and plasma levels of nitrite and nitrate were determined in rats before and after intravenous administration of lipopolysaccharide. Changes in the levels of P450 isoforms and testosterone hydroxylation activity in hepatic microsomes were also determined. To evaluate in vivo CYP3A2 activity, midazolam sleep time was measured. RESULTS: When lipopolysaccharide increased the hepatic inducible type of nitric oxide synthase and plasma levels of nitric oxide metabolites, the intensity of low-spin signal of electron spin resonance responsible for the ferric form of P450 decreased with a concomitant increase in heme-iron nitrosyl complexes in the liver. Lipopolysaccharide-related nitric oxide generation is followed by an early decrease in the levels of cytochrome P450 and of testosterone hydroxylation activity in liver microsomes. Midazolam sleep time was prolonged by lipopolysaccharide. All these early changes were prevented by the inhibitor of nitric oxide synthase, N(G)-iminoethyl-L-ornithine. Moreover, lipopolysaccharide suppressed the gene expression of CYP2C11 and CYP3A2. Decreases in levels of cytochrome P450 and their mRNAs were more pronounced at 24 h after LPS administration, but apparently they are NO-independent. CONCLUSIONS: These results suggest that lipopolysaccharide-induced modulation of cytochrome P450 may occur via the interplay of two different mechanisms and that, especially in the early phase, nitric oxide-dependent inhibition is more important.

Animals↗

PubMed1999

Pharmacokinetic evaluation of biodistribution data obtained with radiolabeled proteins in mice.

Radiolabeling of proteins is a widely used approach to study their in vivo disposition patterns. However, the obtained results may largely depend on the radiolabeling method used. The purpose of the present study was to investigate the effect of the radiolabeling method on the pharmacokinetic analysis of liver targeted protein in mice. Galactosylated bovine serum albumin (Gal-BSA) was labeled with 125I or 111In, using diethylenetriamine-pentaacetic dianhydride (cDTPA) or 1-(4-isothiocyanobenzyl)ethylenediaminetetraacetic acid (SCN-Bz-EDTA) as bifunctional chelating agents. The Gal-BSA was then injected in mice by a bolus intravenous injection. Samples of plasma, urine, liver, kidney, intestine and feces were collected at various time intervals and their radioactivity was measured. In none of the samples examined was there any significant difference in radioactivity distribution originating from the radiolabeling methods within 5 min after administration. After this period, 125I radioactivity in the liver started to decrease significantly faster than that of 111In, which would indicate the intracellular degradation of the protein. Consequently, the reappearance of trichloracetic acid (TCA) soluble 125I radioactivity in the plasma occurred. But whereas the hepatic uptake clearance (CLliver) of [111In]DTPA-Gal-BSA remained constant during 8 h postinjection, the CLliver of [125I]Gal-BSA at 30 min represented only one eighth of its initial values. The CLliver of [111In]SCN-Bz-EDTA-Gal-BSA resembled that of [111In]DTPA-Gal-BSA within 1 h of the experiment but it started to decline after this interval. The observed discrepancies most probably resulted from the formation of different radiolabeled metabolites in the hepatocytes and their different capability of crossing biological membranes. Our findings indicate that among the three methods employed, [111In]DTPA radiolabeling of Gal-BSA is the most appropriate method to study its tissue disposition.

Animals↗