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Y Suhara

Publications and source records attributed to Y Suhara.

At least 37 records · Page 2Linked to original sources
PubMed1990

Antitumor activity of host T and non-T cells recovered from tumor nodules after interferon therapy.

We examined the modification of host T cells of tumor nodules by interferon (IFN) therapy in mouse models. The host cells were recovered from regressing tumor nodules of mice at Day 13 after intradermal tumor inoculation at Day 0 and administration of 5 x 10(5) U/mouse/day IFN at Day 6 to Day 10. These host cells neutralized in vivo Meth A growth in a dose-dependent fashion. In vitro treatment of these cells with anti-Thy 1.2 monoclonal antibody and rabbit sera as a source of complement abrogated their tumor-neutralizing activity, but only partially, indicating that both T cells and non-T cells were involved in tumor neutralization. The finding that host cells from regressing tumor nodules of either Meth A or Meth 1, an antigenically distinct fibrosarcoma, neutralized both Meth A and Meth 1 tumors without much selectivity was consistent with possible non-T cell involvement. Most of these characteristics of host cells of regressing nodules of IFN-administered mice were also noted with host cells of progressing nodules of placebo-administered mice and there was no significant difference in neutralizing activity qualitatively or quantitatively between the two sources of host cells. There was no significant difference in host T and B cell numbers and compositions of regressing and progressing nodules either. These essentially negative findings raise the possibility, among others, that the primary target host cells to be modified by IFN were not T cells, although the therapeutic effect of IFN was dependent on the host T cells.

Animals↗
PubMed1990

[Clinico-pathological evaluation of mesangial IgA deposition of minimal change with nephrotic syndrome].

The case of IgA glomerulonephritis that shows minimal change with nephrotic syndrome is unusual. Thirteen patients of mesangial IgA deposition of minimal change with nephrotic syndrome (IgAMCNS) are discussed in comparison with twenty patients of non IgA deposition of minimal change with nephrotic syndrome (MCNS). On a common basis of hematuria, two groups are undistinguished. On a reaction pattern to steroid treatment, the former is based on IgA nephritis and the latter is based on minimal change with nephrotic syndrome. There is no difference in light microscopical findings between the two groups. Electron microscopically, the former suggests IgA nephritis and the latter suggests minimal change with nephrotic syndrome. In immunofluorescence, the former group is rare to show typical IgA glomerulonephritis. In conclusion, IgAMCNS is considered to be nephrotic syndrome with asymptomatic IgA deposit in mesangium.

Adolescent↗
PubMed1990

[Clinicopathological studies of 10 cases with focal segmental glomerulosclerosis].

The clinical picture, histopathological findings, therapy and prognosis of focal segmental glomerulosclerosis (FSGS) were investigated in a retrospective study involving 10 cases. The age of patient at the time of detection ranged from 3 to 19 years, 11 years on the average, being 9 years or above in 6 cases. There was noted a slight tendency toward predominance of males in this series. The disease was detected casually on the occasion of mass survey of urine at school in 6 cases (60%), while by clinical examination on visiting us with nephrotic syndrome in the other 4 (40%). Of the former 6 cases, 5 developed nephrotic syndrome while placed under medical surveillance. Nine of the 10 cases were treated mainly with corticosteroids, to which 5 (50%) were unresponsive and 4 (40%) responsive, with 1 (10%) of these 4 becoming unresponsive since a recurrence. Corticosteroids were not used in 1 case (10%). During follow-up period (which ranged from 1 to 10 years) 6 experienced an elevation of serum creatinine above 2.0 mg/dl, with 5 of them being unresponsive to corticosteroids and 3 begun on hemodialysis therapy. Histologically, cases in which the sum of the proportions of glomeruli affected with segmental sclerosis and with global sclerosis exceeded 30% and, in addition, there were severe tubulointerstitial lesions tended to have a poor prognosis, while those in which sclerosis involved less than 30% of glomeruli and no interstitial damage was discernible had a relatively favorable prognosis and were more frequently responsive to corticosteroids. These findings led us to conclude that FSGS has an ominous prognosis as reported previously and notably, the prognosis is much poorer for the non-steroid-responding type than for the responding type. The study also suggests that the degree of severity of histological changes is determinant of the prognosis of the disease.

Adolescent↗
PubMed1989

Mature 98,000-dalton acid alpha-glucosidase is deficient in Japanese quails with acid maltase deficiency.

We compared acid alpha-glucosidase of acid maltase-deficient Japanese quails, an animal model of human late-onset glycogenosis type II, with that of normal controls. Antibody produced in a rabbit against acid alpha-glucosidase purified from chicken pectoral muscle cross-reacted with that of Japanese quails. The presence of a 110K and 98K form of acid alpha-glucosidase was confirmed in normal controls by immunoblotting. However the 98K form was absent in the affected quails. Subcellular distribution studies demonstrated that the 98K form, but not the 110K form, was localized in the lysosomes. This suggests that the 110K form is a precursor of the mature 98K form of acid alpha-glucosidase. In the affected quails, the 110K precursor is synthesized, but maturation to the 98K form does not occur or may be extremely deficient.

Animals↗
PubMed1988

Immunostaining of skeletal and cardiac muscle surface membrane with antibody against Duchenne muscular dystrophy peptide.

Duchenne muscular dystrophy (DMD) is a debilitating X-linked muscle disease. We have used sequence information from complementary DNA clones, derived from the gene that is deleted in DMD patients, to generate an antiserum that stains the surface membrane of intact human and mouse skeletal muscle, but not that of DMD patients and mdx mice. Here we identify the protein reacting with this antiserum as a single component of relative molecular mass 210,000 (Mr = 210K) that fractionates with a low-ionic strength extract of intact human and mouse skeletal muscle. It is therefore distinct from the 400 K protein found in the heavy microsomal fraction of normal muscle and identified as a putative product of the DMD gene. We also analyse further the disease specificity of the antiserum. Positive staining is seen in normal controls, and in samples from patients with a wide range of muscular dystrophies other than DMD. Becker muscular dystrophy, which is allelically related to DMD, was the only other exception, and gave a sporadic staining pattern. The demonstration of a specific defect in the surface membrane of DMD muscle fibres substantiates the hypothesis that membrane lesions may initiate muscle degradation in DMD.

Animals↗
PubMed1986

Molecular basis of drug resistance to new antirhinovirus agents.

The modes of action of antirhinovirus agents and mechanisms of resistance to the agents are compared. Chalcone Ro 09-0410, 4',6-dichloroflavan (DCF) and RMI-15,731, which were active against rhinoviruses, inactivated the virus directly. Inactivation was associated with the binding of the agents to the virus particles, since the infectivity, reduced by exposure to the compounds, was restored to the original level by extraction of the agents with chloroform. The binding of [3H]chalcone to rhinovirus type 2 was inhibited by any of the three unlabelled agents. Furthermore, virus sublines selected for resistance to both dichloroflavan and RMI-15,731 showed cross-resistance to chalcone and vice versa. These findings indicate that the three agents exert their activities through the same mode of action (namely binding to or interaction with a specific site on the viral capsid protein) and that the binding or interaction sites for these three agents are either the same or very close to each other. Since the sublines resistant to chalcone and to RMI-15,731 have little or no capability to bind to chalcone, the resistance to these agents is conferred by changes in the viral capsid protein. On the other hand, flavone Ro 09-0179 and enviroxime, which were active widely against picornaviruses, had no ability to inactivate the virus directly, and their antiviral activity was not associated with the capsid protein.

Benzimidazoles↗
PubMed1985

Comparative studies on the modes of action of the antirhinovirus agents Ro 09-0410, Ro 09-0179, RMI-15,731, 4',6-dichloroflavan, and enviroxime.

Modes of action of five antirhinovirus agents were compared. Ro 09-0410, 4',6-dichloroflavan, and RMI-15,731 were active preferentially against human rhinovirus. Serotypes of the virus varied in their susceptibility to these three agents, whereas Ro 09-0179 and enviroxime showed activity against all the serotypes of the virus tested to date. Ro 09-0410, RMI-15,731, and 4',6-dichloroflavan inactivated the virus directly, although 4',6-dichloroflavan did so only slightly. Inactivation by 4',6-dichloroflavan and RMI-15,731 was associated with the binding of the agents to the virus, since the infectivity, reduced by exposure to the agents, was restored to the original level by extraction of the agents with chloroform. The binding of [3H]Ro 09-0410 to human rhinovirus type 2 was inhibited by unlabeled Ro 09-0410, 4',6-dichloroflavan, and RMI-15,731 but not by Ro 09-0179 or enviroxime. Furthermore, subtypes resistant to both 4',6-dichloroflavan and RMI-15,731 showed cross-resistance to Ro 09-0410 and vice versa. On the other hand, sublines resistant to these three agents were not cross-resistant to Ro 09-0179 or enviroxime. These results indicate (i) that Ro 09-0410, 4',6-dichloroflavan, and RMI-15,731 exert their activities through the same mode of action, namely, binding to or interaction with some specific site on the viral capsid protein, and (ii) that the binding or interaction sites for these three agents are either the same or very close to each other.

Antiviral Agents↗
PubMed1985

Treatment regimen and host T-cell-dependent therapeutic effect of interferon in mouse solid tumors.

A highly purified hybrid human interferon (IFN)-alpha A/D, was used to define optimum treatment regimens for Meth A fibrosarcoma intradermally inoculated in syngeneic BALB/c mice. Treatments from the sixth day post-tumor inoculation were most effective, and 10 consecutive injections of IFN completely suppressed the tumor growth for a prolonged time without recurrence after the last injection of IFN. Intraperitoneal and intravenous injections were similarly effective. The therapeutic effect of IFN was abrogated by the injection of rabbit alpha-mouse thymocyte globulin but not normal rabbit globulin. The therapeutic effect of IFN was much poorer in BALB/c nu/nu mice, which are athymic and defective in T-cell immunity, than in BALB/c +/+ mice. Mice in which Meth A growth was completely suppressed by IFN were refractory to Meth A, but not Meth 1 tumor, another antigenically distinct fibrosarcoma, whereas mice in which Meth 1 growth was suppressed completely by IFN were refractory to Meth 1 but not Meth A tumor. These three findings suggest that the therapeutic effect of IFN depended on host T-cell immunity and that tumors were eventually eliminated by tumor-selective antitumor immunity provoked during IFN therapy. Under the present experimental conditions, the direct anticellular activity of IFN was presumed to contribute very little to the therapy for solid tumors, since the therapeutic effect of IFN on three different solid tumors was not correlated with their in vitro sensitivity to this substance: Colon 26, which was as sensitive to IFN as Meth A in the in vitro antiproliferation, responded most poorly to IFN therapy, while Meth A and Meth 1 responded similarly well to IFN therapy, although there was more than a 2500 times difference in their in vitro IFN sensitivity.

Animals↗
PubMed1984

Antivirus agent, Ro 09-0410, binds to rhinovirus specifically and stabilizes the virus conformation.

The antiviral mechanisms of Ro 09-0410 (4'-ethoxy-2'-hydroxy-4,6'-dimethoxychalcone), which inactivates rhinovirus exclusively, have been investigated. It was suggested that Ro 09-0410 bound to human rhinovirus type 2 (HRV-2) and made it inactive, since the reduced infectivity was completely restored to original levels by extraction of the agent with chloroform [H. Ishitsuka, Y. Ninomiya, C. Ohsawa, M. Fujiu, and Y. Suhara (1982) Antimicrob. Agents Chemother. 22, 617-621]. This was confirmed using radioactively labeled Ro 09-0410 and HRV-2. HRV-2 was inactive while bound to the agent, whereas a subline of HRV-2 resistant to the agent had no binding site for the agent. Ro 09-0410 appeared to bind to some specific site(s) on the virion of susceptible virus strains. Treatment of rhinovirus at pH 5 or 56 degrees caused a change of the virion size and greatly reduced its infectivity. Ro 09-0410 could no longer bind to HRV-2 after such treatment. On the other hand, when the virion bound with Ro 09-0410 was treated at pH 5 or 56 degrees, the Ro 09-0410 remained bound and the conformational alteration of the virion did not take place. Furthermore, Ro 09-0410 protected HRV-2 from the reduction of infectivity caused by mild acid or heat treatment, as revealed by infectivity measurements after extraction of the agent with chloroform. These results suggest that Ro 09-0410 binds to the HRV-2 virion and prevents viral replication in the cell.

Antiviral Agents↗
PubMed1983

Microbial Resolution of alpha-Hydroxy Acids by Enantiospecifically Dehydrogenating Bacteria from Soil.

Thirty-three bacterial strains were isolated from soil, utilizing optically asymmetric degradation of dl-2-hydroxy-4-methylpentanoic acid (dl-HMPA) as the screening probe. Those strains were distributed in the following group and genera: Coryneform and Bacillus, Pseudomonas, and Streptomyces. Among them, the most potent strains, Bacillus freudenreichii NRS-137KH20B and Brevibacterium albidum NRS-130KH20B, could perform the resolution of more than 30 g of dl-HMPA per liter within 4 to 5 days of fermentation. Optically pure l- and d-HMPA enantiomers were obtained in more than 80% theoretical yield, whereas the transformed enantiomer was almost quantitatively recovered as 2-oxo-4-methyl-pentanoic acid in the culture broth. The enantiospecific dehydrogenation responsible for this resolution reaction had a rather wide substrate specificity on straight or branched aliphatic C(4) to C(16) 2-hydroxy acids, exhibiting the optima at chain lengths of either C(7) or C(5), although the enantiospecificity was not changed by chain length. The process was thus successfully extended to the preparation of optically pure C(5) to C(9) 2-hydroxy acids.

Journal Article↗
PubMed1983

Microbial Production of Optically Pure l-Iditol by Yeast Strains.

Several yeast strains belonging to genus Candida were found to selectively hydrogenate l-sorbose with enantiomeric specificity, yielding optically pure l-iditol in the culture broth. The most active strain, isolated from a commercial lemon, was identified as Candida intermedia, which produced 50 g of l-iditol per liter from 150 g of l-sorbose per liter during a 5-day fermentation period (35% yield).

Journal Article↗
PubMed1983

New alpha-amylase inhibitor, trestatins. I. Isolation, characterization and biological activities of trestatins A, B and C.

Trestatin complex which exhibited a potent inhibitory activity on various alpha-amylases has been isolated from the culture filtrate of Streptomyces dimorphogenes nov. sp. NR-320-OM7HB. Three major components, trestatins A, B and C, have been purified by adsorption and ion-exchange chromatography. Their spectral and chemical properties suggested that trestatins were novel basic oligosaccharide homologues each characterized by the possession of a trehalose moiety at the non-reducing end of the molecule.

Chromatography, High Pressure Liquid↗
PubMed1982

Antipicornavirus flavone Ro 09-0179.

Ro 09-0179 (4',5-dihydroxy-3,3',7-trimethoxyflavone), isolated from a Chinese medicinal herb, was found to have potent antiviral activity. It selectively inhibited the replication of human picornaviruses, such as rhinoviruses and coxsackieviruses in tissue culture, but not other DNA and RNA viruses. Ro 09-0298 (4',5-diacetyloxy-3,3',7-trimethoxyflavone), an orally active derivative of Ro 09-0179, prevented coxsackievirus (B1) infection in mice. The critical time for the inhibition of rhinovirus replication by Ro 09-0179 was 2 to 4 h after virus adsorption, i.e., in the early stages of virus replication. It markedly inhibited coxsackievirus and rhinovirus RNA synthesis in infected HeLa cells, but not in a cell-free system using the RNA polymerase complex isolated from the infected cells. In the infected cells, the RNA polymerase complex was not formed in the presence of Ro 09-0179. Therefore, it is suggested that Ro 09-0179 interferes with some process of viral replication which occurs between viral uncoating and the initiation of viral RNA synthesis.

Animals↗
PubMed1982

Direct and specific inactivation of rhinovirus by chalcone Ro 09-0410.

Studies of various analogs related to the antipicornavirus agent, 4',5-dihydroxy-3,3',7-trimethoxyflavone (Ro 09-0179), led to the identification of 4'-ethoxy-2'-hydroxy-4,6'-dimethoxychalcone (Ro 09-0410), a new and different type of antiviral agent. Ro 09-0410 had a high activity against rhinoviruses but no activity against other picornaviruses. Of 53 rhinovirus serotypes so far tested, 46 were susceptible to Ro 09-0410 in HeLa cell cultures. The concentration of Ro 09-0410 inhibiting 50% of the types of rhinovirus was about 0.03 micrograms/ml, whereas the 50% cytotoxic concentration was 30 microgram/ml. Ro 09-0410 inactivated rhinoviruses in direct dose-, time-, and temperature-dependent fashion. Since infectivity, reduced by exposure to the agent, completely regained the original level by extraction of the agent with chloroform, the inactivation may be associated with the binding of the agent to some specific site of the rhinovirus capsid.

Antiviral Agents↗
PubMed1981

Regio-selective 10-hydroxylation of patchoulol, a sesquiterpene, by pithomyces species.

Of some 350 microorganisms screened, four strains of Pithomyces species were found to carry out regio-selective hydroxylation of patchoulol, a sesquiterpene, to 10-hydroxypatchoulol: Pithomyces sp. NRJ201, P. chartarum NRJ210, and, to a lesser extent, P. cynodontis ATCC 26150 and P. atro-olivaceus IFO 6651 were found to catalyze this reaction. A method has been developed by which 10-hydroxypatchoulol was obtained in 25 to 45% yields in 1- to 5-liter fermentation jars at 2 to 4 g of patchoulol per liter and isolated as pure material in 30% yields.

Journal Article↗
PubMed1978

Differential mutagenicity of reaction products of various pyrazolones with nitrite.

Four pyrazolones in frequent use, i.e. antipyrine (AP), aminopyrine (AMP), sulpyrine (SP) and isopropylantipyrine (IPA), were compared for their reactivity with nitrite and for the in vitro mutagenicity of their reaction products by Ames' reversion tests. In various acidic solutions at 37 degrees C, AP, AMP and SP were found to react easily with nitrite and yield various products including dimethylnitrosamine (DMNA) and 4-nitrosoantipyrine (4-NAP) in the cases of AMP and AP, respectively. When tested with Salmonella typhimurium TA100 and TA98 after lyophilization, the reaction products of AP (AP-N) were found to be mutagenic in both strains, while products of AMP and SP (AMP-N and SP-N) were mutagenic only in TA100. The presence of unknown ultimate mutagens, other than DMNA and 4-NAP, were evidenced in AP-N, AMP-N and SP-N. Incubation with S-9 mixture did not affect the mutagenicity of SP-N and decreased that of AP-N and AMP-N. In clear contrast to AP, AMP and SP, it was found that IPA remained essentially intact upon reaction with nitrite. No mutagenicity was detected with the reaction mixture (IPA-N) in either strain.

Aminopyrine↗