Biomedical subjects

H Toyoda

Publications and source records attributed to H Toyoda.

At least 145 records · Page 8Linked to original sources

PubMed1997

Distribution of mRNA for human epiregulin, a differentially expressed member of the epidermal growth factor family.

We have recently identified epiregulin as a new growth regulator and a member of the epidermal growth factor (EGF) family. Epiregulin has certain characteristics that are different from those of the classical members of the EGF family, EGF and transforming growth factor alpha, including mitogenic responses on several normal cells and binding to EGF receptors on epidermoid carcinoma A431 cells. In the present study we cloned and identified the expression of human epiregulin transcript. The human epiregulin gene encoded a 163-residue putative transmembrane precursor containing an EGF-like domain in the internal segment, and the structural organization was similar to that of other members of the EGF family that bind to EGF receptors. Northern blot analysis showed the expression of human epiregulin to be mainly on peripheral blood macrophages and the placenta in normal tissues, and was highest on epithelial tumour cell lines in various types of tumour cell lines. The expression profile was quite different from that of other members of the EGF family in normal and tumour cells. Recombinant expression in mammalian cells also showed that human epiregulin was secreted as a soluble form of approx. 5 kDa that is biologically active on the basis of the stimulation of DNA synthesis. Our findings suggest that epiregulin is involved in certain physiological processes such as maintenance or development of normal cell growth, and the progression of carcinomas.

3T3 Cells↗

PubMed1997

Structural differences and the presence of unsubstituted amino groups in heparan sulphates from different tissues and species.

This study presents a comparison of heparan sulphate chains isolated from various porcine and bovine tissues. 1H-NMR spectroscopy (500 MHz) was applied for structural and compositional studies on intact heparan sulphate chains. After enzymic digestion of heparan sulphate using heparin lyase I (EC 4.2.2.7) II and III (EC 4.2.2.8), the compositions of unsaturated disaccharides obtained were determined by analytical capillary electrophoresis. Correlations between the N-sulphated glucosamine residues and O-sulphation and between iduronic acid content and total sulphation were discovered using the data obtained by NMR and disaccharide analysis. Heparan sulphate chains could be classified into two groups based on the sulphation degree and the iduronic acid content. Heparan sulphate chains with a high degree of sulphation possessed also a significant number of iduronic acid residues and were isolated exclusively from porcine brain, liver and kidney medulla. The presence and amount of N-unsubstituted glucosamine residues (GlcNp) was established in all of the heparan sulphates examined. The structural context in which this residue occurs was demonstrated to be: high sulphation domain --> 4)-beta-D-GlcAp-(1 --> 4)-alpha-D-GlcNp-(1 --> 4)-beta-D-GlcAp-(1 --> low sulphation domain (where GlcNp is 2-amino-2-deoxyglucopyranose, and GlcAp is glucopyranosyluronic acid), based on the isolation and characterization of a novel, heparin lyase III-derived, GlcNp containing tetrasaccharide and hexasaccharide. The results presented suggest that structural differences may play a role in important biological events controlled by heparan sulphate in different tissues.

Amino Sugars↗

PubMed1997

Shear stress-induced myosin association with cytoskeleton and phosphorylation in human platelets.

Upon platelet activation by a high shear stress (108 dyne/cm2), actin and actin-binding protein increased rapidly into the Triton-insoluble cytoskeleton, whereas the association of myosin increased gradually. The amounts of cytoskeleton-associated myosin depended on the extent of aggregation. Preceding the maximal aggregation and ATP secretion, the 20 kDa light chain of myosin (MLC) is rapidly phosphorylated to approx. 45% of 20 kDa MLC and is then dephosphorylated. Cytoskeletal association of myosin and phosphorylation of 20 kDa MLC was inhibited by OP-41483, a prostaglandin I2 analog, which inhibited the full aggregation response to shear stress. Exposure to high shear stress resulted in an increased association of myosin light chain kinase and protein phosphatase types 1 and 2A with the cytoskeleton, while the cytoskeletal association of protein kinase C was not evident. These results indicate that 20 kDa MLC phosphorylation is involved in shear stress-induced platelet activation, and that cytoskeletal association of protein phosphatases may regulate the phosphorylation level of cytoskeletal elements such as myosin together with myosin light chain kinase.

Blood Platelets↗

PubMed1997

Quasispecies nature of hepatitis C virus and response to alpha interferon: significance as a predictor of direct response to interferon.

BACKGROUND/AIMS: We evaluated the significance of the quasispecies nature of HCV as a predictor of the response to alpha interferon therapy in patients with chronic hepatitis C. METHODS: Natural alpha interferon was administered in 62 patients for 24 weeks (daily for 2 weeks, then three times weekly for 22 weeks) and factors were analyzed that could affect the response. HCV subtype, HCV RNA concentrations and the number of HCV quasispecies were evaluated before treatment. HCV RNA concentrations were measured by branched DNA probe assay. The number of HCV quasispecies was measured by fluorescence single-strand conformation polymorphism analysis. RESULTS: The HCV RNA concentration (p < 0.0001), HCV subtype (p = 0.0076), and the number of HCV quasispecies (p = 0.0024) were significantly associated with a complete response. Multivariate analyses showed that the number of HCV quasispecies was an independent predictor of the disappearance of HCV RNA during the administration of alpha interferon, but did not predict a relapse after its completion. Pretreatment concentration of HCV RNA was the only factor that was related to a long-term disappearance of HCV RNA. CONCLUSIONS: The number of HCV quasispecies was significantly related to the response to alpha interferon early in its administration. The pretreatment concentration of HCV RNA was mainly related to a relapse following completion of treatment.

Adult↗

PubMed1997

Changes in blood supply in small hepatocellular carcinoma: correlation of angiographic images and immunohistochemical findings.

BACKGROUND/AIMS: To assess the changes occurring in blood flow with growth in small hepatocellular carcinomas, we analyzed the angiographic features and immunohistochemical findings in 35 hepatocellular carcinomas less than 2 cm in diameter. METHODS: Hepatocellular carcinomas were evaluated by digital subtraction angiography (DSA), ultrasound angiography with intraarterial CO2 microbubbles (USAG), and computed tomography during arterial portography (CTAP). Immunohistochemically, hepatocellular carcinomas were evaluated using QB-end/10 (QB) monoclonal antibody. RESULTS: All 18 moderately-differentiated hepatocellular carcinomas stained positively with QB antibody. No hepatocellular carcinomas without attenuation on CTAP were positive by immunohistochemistry, and two hepatocellular carcinomas with attenuation on CTAP also lacked staining. We observed four hepatocellular carcinomas without hypervascularity on DSA or USAG, which stained positively with QB antibody; these hepatocellular carcinomas had fatty metamorphosis. CONCLUSIONS: 1. Immunohistochemical findings are closely associated with angiographic findings regarding changes in blood supply. 2. All moderately-differentiated hepatocellular carcinomas have characteristics of hypervascularity, both by angiographic images and by immunohistochemistry. 3. The increase in arterial blood supply occurs later than the decrease in portal perfusion, which may indicate that the decrease in portal perfusion may not be the direct result of replacement by angiogenesis. 4. Some hepatocellular carcinomas with fatty metamorphosis, which are often hypovascular by angiographic evaluation, have hypervascular immunohistochemical characteristics.

Aged↗

PubMed1997

Effect of immunosuppression on composition of quasispecies population of hepatitis C virus in patients with chronic hepatitis C coinfected with human immunodeficiency virus.

BACKGROUND/AIMS: To study the effects of the immunosuppression caused by the reduction of CD4 activity on the composition of hepatitis C virus (HCV) populations, we analyzed the number of HCV quasispecies clones and the nucleotide diversity of the hypervariable region 1 (HVR1) of HCV in 37 patients with hemophilia with persistent HCV infection, with or without human immunodeficiency virus (HIV). METHODS: The numbers of HCV quasispecies clones were measured by fluorescence single-strand conformation polymorphism analysis. Direct sequencing was used to analyze the degree of diversity of HVR1. We compared these values according to coinfection with HIV, and CD4 counts of patients. RESULTS: There were no differences in either the number of HCV clones or the diversity between patients with and without HIV coinfection. In HIV coinfected patients the diversity decreased in association with the decrease in CD4 count while the number of HCV clones did not. The diversity of HVR1 was 3.64 +/- 5.03% in patients with a CD4 count < 50/microliters and 14.92 +/- 6.03% in patients with a CD4 count > or = 50/microliters; it was significantly lower in the former (p = 0.0002). CONCLUSIONS: A severe reduction in the CD4 count, which is considered to cause a decline in the activity of helper T-lymphocytes, induced changes in the composition of HCV populations; one or a few quasispecies clones are predominant in the HCV population in the serum of individual patients.

Adult↗

PubMed1997

Significance of tumor vascularity as a predictor of long-term prognosis in patients with small hepatocellular carcinoma treated by percutaneous ethanol injection therapy.

BACKGROUND/AIMS: We estimated the significance of the vascularity of small hepatocellular carcinoma (HCC) as a predictor of long-term prognosis in patients treated with percutaneous ethanol injection therapy (PEIT/PEI). METHODS: Fifty-four patients who have been followed-up in our hospital and who had HCC less than 20 mm in diameter were observed for 199 to 2074 days. Hepatic angiography (digital subtraction angiography; DSA and ultrasound angiography with intraarterial CO2 microbubbles; USAG) was performed before treatment in all cases, and the vascularity of the tumor was clinically evaluated. The survival rate was analyzed according to this vascularity. RESULTS: Of the 54 tumors, 24 had tumor stain on DSA, while 30 did not, and 38 showed enhancement on USAG, while 16 did not. The 3- and 5-year survival rates were 48.7 and 34.1% and 89.7 and 69.7% of patients with negative staining HCC (p = 0.0723). The rates were 48.6 and 36.7%, respectively, of patients with positive enhancement HCC on USAG, and both rates were 85.7% of patients with negative enhancement HCC (p = 0.0231). CONCLUSIONS: Tumor vascularity will play a role in the long-term prognosis of these patients with small HCC when they are treated with PEIT/PEI.

Administration, Cutaneous↗

PubMed1997

Effect of antipsychotic drugs on the gene expression of NMDA receptor subunits in rats.

It has been hypothesized that glutamatergic neurons play an important role in clinical manifestations of schizophrenia and that the therapeutic effect of antipsychotic drugs is related to glutamatergic neurotransmission. To elucidate the effect of antipsychotic drugs on glutamatergic transmission, we examined gene expressions of NMDA receptor subunits R1, R2A, R2B and R2C in the whole brains of rats after acute and chronic administrations of haloperidol and sulpiride, using the Northern blot technique. The levels of NMDAR2B mRNAs decreased after the acute administration of haloperidol, but showed no change after the chronic administration. The levels of NMDAR2A and R2B mRNAs decreased after the acute administration of sulpiride, whereas the levels of R2A and R2B increased following the chronic administration. Neither haloperidol nor sulpiride influenced NMDAR1 mRNA levels. These data support differential expression of NMDA receptor subunits in rats upon treatment with haloperidol and sulpiride. The results imply that NMDAR2 subunits may be crucial in the regulation and modification of antipsychotic drugs.

Animals↗

PubMed1997

Patterns of recurrence after initial treatment in patients with small hepatocellular carcinoma.

To assess intrahepatic metastasis (IM) and multicentric occurrence (MO) after initial treatment of small hepatocellular carcinomas (HCC) < or = 2 cm in diameter, we performed clinical and pathological studies in 112 patients who underwent percutaneous ethanol injection therapy (PEIT) or hepatic resection for HCC from January 1985 to December 1994. Patients with intrahepatic recurrences were classified into two groups based on the type of recurrence: the IM group (n = 29, 50.9%) and the MO group (n = 28, 49.1%). Overall recurrence rates after initial treatment were 23.7% at 1 year, 64.5% at 3 years, and 76.1% at 5 years. In patients with IM, the majority of intrahepatic recurrences were observed within 3 years of initial treatment and the primary HCC lesions were closely related to the degree of tumor cell differentiation. Alternatively, intrahepatic recurrences occurred throughout the follow-up period in patients with MO, and the evidence of underlying liver disease (anti-HCV [antibody to hepatitis C virus] positive) and elevated serum alfa-fetoprotein (AFP) concentrations were closely associated with intrahepatic recurrence. Prognoses following additional treatment in MO group patients were superior to those in IM group patients. These results suggest that differentiation between IM and MO in patients with HCC is important for understanding the development and biological behavior of the tumor. That is, the early detection of intrahepatic recurrence and the institution of appropriate additional therapy (PEIT or hepatic resection) may prolong survival in patients with MO.

Adult↗

PubMed1997

Significance of early measurement of serum hepatitis C virus RNA in predicting response to interferon therapy in patients with chronic hepatitis C.

BACKGROUND: Interferon can induce complete clearance of hepatitis C virus (HCV) in some patients with chronic hepatitis C. However, various side effects often require cessation of administration during the treatment period. Early prediction of response to interferon would be helpful. We evaluated measurement of serum HCV RNA 2 weeks after starting interferon as a predictor of response. METHODS: The presence of HCV RNA was measured in serum 2 weeks after starting therapy in 85 patients receiving natural interferon a (total 480 MU). RESULTS: Twenty-seven of 38 patients (71.1%) in whom serum HCV RNA had disappeared at 2 weeks achieved a sustained response. Only two out of 47 patients (4.3%) in whom serum HCV RNA had not disappeared at 2 weeks achieved a sustained response. Of 42 patients with pre-treatment HCV RNA concentrations less than 1 x 10(6) eq/ml, 26 of 30 patients (86.7%) whose HCV RNA had disappeared at 2 weeks achieved a sustained response, while only one of 12 patients (8.3%) whose HCV RNA was still detectable at 2 weeks had a sustained response. CONCLUSION: Clearance of serum HCV RNA after 2 weeks of treatment with interferon was more likely in patients with lower pre-treatment HCV RNA concentrations and they had a high likelihood of achieving a sustained response. In patients in whom serum HCV RNA was still detectable after 2 weeks of interferon therapy, a sustained response was most unlikely.

Adult↗

PubMed1997

Specific interaction of polypyrimidine tract-binding protein with the extreme 3'-terminal structure of the hepatitis C virus genome, the 3'X.

We previously identified a highly conserved 98-nucleotide (nt) sequence, the 3'X, as the extreme 3'-terminal structure of the hepatitis C virus (HCV) genome (T. Tanaka, N. Kato, M.-J. Cho, and K. Shimotohno, Biochem. Biophys. Res. Commun. 215:744-749, 1995). Since the 3' end of positive-strand viral RNA is the initiation site of RNA replication, the 3'X should contribute to HCV negative-strand RNA synthesis. Cellular factors may also be involved in this replication mechanism, since several cellular proteins have been shown to interact with the 3'-end regions of other viral genomes. In this study, we found that both 38- and 57-kDa proteins in the human hepatocyte line PH5CH bound specifically to the 3'-end structure of HCV positive-strand RNA by a UV-induced cross-linking assay. The 57-kDa protein (p57), which had higher affinities to RNA probes, recognized a 26-nt sequence including the 5'-terminal 19 nt of the 3'X and 7 flanking nt, designated the transitional region. This sequence contains pyrimidine-rich motifs and shows similarity to the consensus binding sequence of the polypyrimidine tract-binding protein (PTB), which has been implicated in alternative pre-mRNA splicing and cap-independent translation. We found that this 3'X-binding p57 is identical to PTB. The 3'X-binding p57 was immunoprecipitated by anti-PTB antibody, and recombinant PTB bound to the 3'X RNA. In addition, p57 bound solely to the 3'-end region of positive-strand RNA, not to this region of negative-strand RNA. We suggest that 3'X-PTB interaction is involved in the specific initiation of HCV genome replication.

Base Sequence↗

PubMed1997

Organization of the lamina propria mucosae of rat intestinal mucosa, with special reference to the subepithelial connective tissue.

Light microscopy, scanning electron microscopy and transmission electron microscopy have been used to delineate the structure and function of the lamina propria mucosae in the rat jejunum. In silver-impregnated sections, the adepithelial surface of the lamina propria mucosae was framed by a sheet of reticular fibers (reticular sheet). Short-term (3-hour) immersion of jejunal tissues in 2 N NaOH solution enabled us to simultaneously view networks of reticular fibrils and fibroblasts residing in the subepithelial connective tissue under a scanning electron microscope. The reticular fibrils, which measured about 40 nm in diameter and were interwoven in dense networks, formed a sheet 2-3 microns thick. In the villi, this sheet contained numerous foramina ranging from 3 to 7 microns in diameter, through which lymphocytes, macrophages, basal extensions of epithelial cells and fat particles traversed. The reticular sheet in the domes of isolated lymphoid nodules was markedly porous, and many lymphocytes migrated into or out of the epithelium through the foramina. The formaina of the reticular sheet may participate in the communication between the intestinal epithelium and the lamina propria mucosae. It was noted that the foramina of the reticular sheet in the villi were surrounded by end feet of the cytoplasmic processes of fibroblasts. In addition, these fibroblasts were combined with lymphocytes or dendritic cells in the lamina propria mucosae.

Animals↗

PubMed1997

[Activation of skin cells by inorganic compounds].

It has been known that the stimulation of skin cells by physiologically active substances is accompanied by the quantitative and qualitative alterations of the glycosaminoglycans (GAGs) in skin. This phenomenon make it possible to evaluate the activity of test substances for the stimulation of skin cells. The purpose of our study is to elucidate the effectiveness of inorganic compounds for the stimulation of skin cells. (1) The cultured skin cells including keratinocytes and fibroblasts, (2) the cultured model skin constituted of collagen gel, fibroblasts and keratinocytes, and (3) the mouse damaged skin were used in the present study. The results obtained from these studies demonstrate that inorganic substances commonly have a possibility to activate cyclic AMP-dependent protein kinase (A-kinase), and the A-kinase activation results in an increase in GAGs. These findings brought the scientific basis for the effectiveness of the Japanese traditional balneotherapy for damaged skin.

Animals↗

PubMed1997

Campylobacter fetus subsp. fetus cholecystitis in a patient with advanced hepatocellular carcinoma.

Acute cholecystitis due to Campylobacter fetus subsp. fetus is very uncommon. We report a case of cholecystitis and obstructive jaundice in which cultured bile grew this organism. The patient had a 4-year history of hepatocellular carcinoma, resulting in common bile duct obstruction due to abdominal lymph node metastasis. Microscopic examination of her bile showed multiple Gram-negative curved organisms and C. fetus subsp. fetus was isolated under microaerophilic conditions. Therefore, we should be aware of this organism and use microaerophilic culture in association with the result of microscopic examination of bile specimens.

Campylobacter Infections↗

PubMed1997

[A new wave of behavior genetic modeling using covariance structure analysis].

A number of useful methods for analyzing covariance structure have been proposed in the studies of human behavior genetics, reflecting the fact that the behavior genetic studies are one of the main origins of covariance structure model. In this paper, I review recent progress on methodology for behavior genetic studies of twins and families from the standpoint of the structural equation modeling. Especially, genetic ACE (additive genetic, common environment and random environment) model, multivariate ACE model, genetic factor analysis model and twin-parent model are focused upon. This review also discusses how to construct applied structural equation models which are useful for psychological research.

Factor Analysis, Statistical↗

PubMed1997

[Hepatitis GB virus C infection in Japanese hemophiliacs with persistent hepatitis C virus infection].

We investigated the prevalence of infection of GBV-C, which has been cloned recently and is considered a parenterally transmissible virus. Ninety-one Japanese hemophiliacs who were persistently infected with HCV were evaluated. The presence of GBV-C RNA was measured by nested RT-PCR. We analyzed the prevalence and the association with subtypes of coinfected HCV. 20.9% of hemophiliacs were infected with GBV-C. The distribution of HCV subtypes of patients who are coinfected with GBV-C was similar to that of patients who are coinfected with HIV, and the prevalence of GBV-C infection of patients with HCV subtype la was significantly higher than that of patients without HCV subtype la. High prevalence of GBV-C infection was observed in Japanese hemophiliacs, and most were thought to be imported isolates from foreign origins, as well as HIV infection in these patients.

Adult↗

PubMed1997

[In vivo evaluation of the new antithrombogenic reservoir-catheter coated with polymer blend copolymer].

We evaluated the antithrombogenicity of 4F-catheters coated with the new antithrombogenic material fluorine-acryl- styrene-urethane-silicone (FASUS) graft-block copolymer by dissecting microscopic and scanning electron microscopic observations. These catheters were temporarily used for the infusa-A-port, which was prepared for the treatment of four patients with bladder cancer. Two heparin-coated catheters were also evaluated. All FASUS-coated catheters contained thrombi consisting of red thrombi and/or fibrin thrombi. Massive red thrombus was seen at the site of curvature of the catheters, 1 cm distal to the tip of the catheter. However, the portion 20 cm distal to the tip of the catheter had no red thrombus, but contained minimal fibrin thrombus or plasma protein. The heparin-coated catheters showed the same findings as the FASUS catheters. The FASUS-coated catheters were not superior in antithrombogenicity to the heparin-coated catheters. It was concluded that the FASUS-coated catheters used in this study seemed to have problems in regard to their preshaped curvature and the material used in catheter. These aspects need to be improved.

Aged↗

PubMed1997

[Complete tumor regression obtained by chemoendocrine therapy including toremifene in two cases of pulmonary metastasis of breast cancer with a history of tamoxifen treatment].

Two cases of recurrent breast cancer, for which combined therapy using toremifene and oral chemotherapeutic agents were effective, are reported. In case 1, high-dose toremifene (120 mg/day) and 5'-DFUR were administered to a forty-seven-year-old woman with lung metastasis of estrogen-receptor positive breast cancer, who had been previously treated with polychemotherapy and tamoxifen. A complete response was obtained after six months of treatment and this condition has remained for longer than one year. In case 2, a fifty-year-old woman developed liver and lung matastasis of breast cancer with increased tumor marker levels. Forty mg/day of toremifene and oral cyclophosphamide was started and transarterial embolization of the hepatic artery using lipiodol, adriamycin and mitomycin C was performed. Both hepatic and pulmonary metastasis disappeared, and the tumor maker level was normalized one month later. No regrowth of the tumors has been observed for more than six months. The chemosensitizing effect of toremifene might be responsible for the favorable effects on these matastases of breast cancer.

Adenocarcinoma↗