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Biomedical subjects

N Ishida

Publications and source records attributed to N Ishida.

At least 307 records · Page 17Linked to original sources

Failure in chymotrypsin enhancement of human rotavirus infectivity.

Effects of alpha-chymotrypsin on human rotavirus infectivity and hemagglutination activity were investigated using the KUN strain which was grown in the absence of trypsin and noninfectious. No activating effect of the enzyme on the virus infectivity was found, while HA titers of the virus rapidly decreased after exposure to the enzyme.

Catalysis↗

High resolution G-banding analysis in aniridia.

The authors investigated eight cases of aniridia by high resolution G-banding analysis (750 bands). A deletion of the short arm of chromosome 11 was found in two cases. One of these involved a three months old boy who was suspected of having Wilms' tumor. After elaborate investigations by pediatric surgeons, Wilms' tumor was found in his left kidney and was successfully removed in its early stage. These results suggest that high resolution G-banding analysis should be performed in all cases of infantile aniridia as a screening test for early detection of Wilms' tumor.

Child, Preschool↗

[Determination of antimony in nail and hair by thermal neutron activation analysis].

The concentration of antimony in nail and hair was determined by thermal neutron activation analysis. Samples were collected from the workers of an antimony refinery, inhabitants near the refinery, and residents in control area. They were irradiated by Kyoto University 5 000 kW Reactor for 1 h, and cooled for 30 to 100 days. After cooling, the concentration of Sb in nail and hair was estimated by measuring the intensity of gamma-ray from 124Sb of the samples, then the samples were washed by 0.1% aqueous solution of nonionic surface active agent in an ultrasonic cleaner. The gamma-ray spectrometry was done again (after washing). The concentration of Sb in nail before washing was 730 ppm for the workers, 2.46 ppm for habitants near the refinery, and 0.19 ppm for the control; after washing, it became 230 ppm for the workers, 0.63 ppm for habitants, and 0.09 ppm for the control. The concentration of Sb in hair before and after washing was 222 ppm and 196 ppm for the workers, and 0.21 ppm and 0.15 ppm for the control, respectively.

Antimony↗

[The role of cytokines in cancer therapy].

A variety of normal tissue or malignant cells can produce and/or release various biologically active substances (hormone-like mediators) now collectively called cytokines. Because immunological and non-immunological responses of malignant cells were modified by many of them, some cytokines have been employed as so-called Biological Response Modifiers (BRM) in the treatment of cancers in animals and humans. This overview discussed a few of the difficulties, probably inherent in cytokine therapy, that have already been encountered in early clinical trials as well as some of those that can be anticipated in future work. These include unexpected and undesirable reactions due to the systemic administration in relatively large amounts of a cytokine that is, under physiological conditions, supposed to act as a paracrine and/or autocrine among cells located within a limited distance. Even a pure recombinant preparation of a cytokine is now known to affect multiple target cells if they are accessible to it. Furthermore, this kind of therapy may sometimes be little more than a shot in the dark, since the physiological balance (homeostasis) among many of the cytokines present or produced in a host receiving a large quantity of exogenous cytokines is not well understood. Making the situation still more complicated, many types of tumor cells are known to release some of these cytokines spontaneously. Many challenging problems remain to be solved before we can confidently prescribe a cocktail of cytokines precisely suitable for a given patient according to the individual's in vivo cytokine profile. Nevertheless, in spite of all these reservations, cytokine therapy has been too frequently beneficial to be allowed to be discouraged. "Out of this nettle, danger, we pluck this flower, safety".

Biological Products↗

Development of alumina ceramic bipolar hip prosthesis and clinical application.

The concept of the bipolar type prosthesis is that the articular motion is observed primarily between the HDP bearing insert and the inner head, thereby avoiding the greater frictional shear force between the prosthetic head and acetabulum found with the traditional one piece endoprosthesis. A newly developed ceramic bipolar hip prosthesis utilizes an outer head composed of bio-inert fine alumina ceramic rather than a metal head. The mechanical strength of this prototype bipolar hip prosthesis was tested with static load and impact force, and the dynamic fatigue strength was also tested with repeated loads. Results were judged to show that the device has strength adequate for clinical use. The hip prostheses has been clinically applied in replacement of the femoral head of a neck fracture, femoral head necrosis and osteoarthritic hip. Finally, using a mathematical model, the so-called self-centering effect due to center offset between outer and inner heads is discussed.

Adult↗

Sequence of 2,617 nucleotides from the 3' end of Newcastle disease virus genome RNA and the predicted amino acid sequence of viral NP protein.

DNA fragments complementary to the Newcastle disease virus genome (strain D26) were cloned and sequenced. The sequence of 2,617 nucleotides from the 3' end of the genome was determined and an open reading frame (OP-1) consisting of 1,467 nucleotides, most likely encoding NP protein, was found in this region. This was followed by a second unfinished open reading frame (OP-2) of at least 729 nucleotides which continued beyond the 2,617th nucleotide. Another relatively short (312 nucleotides long) open reading frame (OP-2') was found overlapping with OP-2, but its significance is still unclear. The amino acid sequence deduced from the nucleotide sequence of OP-1 showed a moderate homology to that of the NP protein of Sendai virus in the central portion of the peptide. The leader sequence of 53 nucleotides was also identified. The 5' end of mRNAs synthesized in the infected cells was analyzed and found to be m7GpppA, suggesting that the transcription of viral mRNAs starts with A, but not with G residue.

Amino Acid Sequence↗

Rapid induction of nucleoside-diphosphate kinase in HeLa S3 cells by human-type interferons.

Nucleoside-diphosphate (NDP)-kinase can be considered to be induced by human-type interferons (HuIFNs) rapidly, since an enzyme increase was detected within 2 h of incubation of HeLa S3 cells with HuIFNs, while incubation with heterologous mouse IFNs had no such effect. The enzyme increase induced by HuIFNs reached a plateau at 6 h after treatment. Actinomycin D (0.5 microgram/ml) significantly blocked the enzyme increase induced by HuIFNs in the cells. A possible biological role of the enzyme in the IFN-induced biochemical events is discussed.

Adenosine Diphosphate↗

Seroepidemiological studies on a non-A, non-B hepatitis specific antigen/antibody system (SO-antigen/anti-SO).

The patients and staff members of a haemodialysis unit were examined for their serological responses to SO-antigen, which was isolated from the urine of epidemic type non-A, non-B hepatitis patients at Tohoku University Hospital. To understand how SO-antigen or SO-antigen-related aetiology can be incriminated for the hepatitis found in the haemodialysis unit, the prevalence of SO-antigen/anti-SO system and hepatitis A and B virus-related antibodies was compared in the sera of patients and staff members. Although the SO-antigen was rarely detected in the serum, anti-SO antibody was frequently detected in the sera of patients and staff. A significantly higher prevalence was found in the serum of patients (15%, 54 out of 361) than staff members (7.1%, 13 out of 184) and volunteer blood donors (1%, 3 out of 305). The same prevalence percentages of HBV-related antibodies (either positive for anti-HBs or anti-HBc) and anti-HAV were observed among the patients, staff, and volunteer blood donors, irrespective of whether the sera were anti-SO positive or negative. Among the staff, anti-SO antibody was more frequently found in those with a history of acute hepatitis (16.7%, 3 out of 18) than in those without (6%, 10 out of 166). These prevalence ratios conformed with those of HBV-related antibodies, but the same prevalence ratios of antibody to HAV were observed between the staff with and without a history of acute hepatitis. These results indicate that the SO-antigen/anti-SO system or entity related to this immune system is distinct from HBV or HAV, and this immune system was found widely in the haemodialysis unit where type B and non-A, non-B hepatitis were also found frequently.

Allied Health Personnel↗

Virus excretion and cell-mediated immunity during cytomegalovirus infection among healthy infants and children.

Specific cell-mediated immunity (CMI) and virus isolation were examined longitudinally to clarify the mechanism of the cessation of virus excretion in inapparent cytomegalovirus (CMV) infection among healthy infants and children. We measured leukocyte procoagulant activity (LPCA) responses to CMV antigen and to a purified protein derivative of tuberculin (PPD), with results expressed as a percentage reduction of recalcification (RC) time. Based on the results in seropositive and seronegative adult control subjects, reductions in RC time of more than 10% were considered indicative of a positive LPCA response. The CMV-specific LPCA response was negative in all infants shedding the virus, despite the presence of circulating antibodies, but were converted from negative to positive when the virus excretion ceased. This suggests that cessation of the virus excretion in inapparent CMV infection among healthy infants and children probably results from the specific CMI.

Adult↗

Characterization of monoclonal antibodies against human rotavirus hemagglutinin.

Three monoclonal antibodies capable of specifically inhibiting hemagglutination of human rotavirus were produced. Their hemagglutination inhibition (HI) activity was specific to the homologous strain (KUN) used for immunization. The monoclonal antibodies with HI activity were highly effective in neutralizing the infectivity of the KUN strain. These antibodies reacted with Vp80, and 80,000 molecular weight (MW) protein present in the viral outer shell. It was confirmed by immunoblotting assay with the monoclonal antibodies that the antigenic site of human rotavirus hemagglutinin (HA) resides on Vp80 and on its smaller trypsin cleavage products Vp30 (MW 30,000) and Vp24 (MW 24,000). Immunofluorescence studies using the antibodies revealed that the HA antigen of the KUN strain developed at the final stage of virus maturation.

Animals↗

Pronounced antitumor effect of LAK-like cells induced in the peritoneal cavity of mice after intraperitoneal injection of OK-432, a killed streptococcal preparation.

More than 80% of BALB/c mice bearing BAMC-1 ascites tumor were completely cured after five consecutive (once every 2 days) i.p. injections of a 0.1 mg dose of OK-432, beginning on day 2 after tumor implantation. The antitumor effect of OK-432 was abolished in athymic nu/nu mice and in anti-thymocyte globulin-treated euthymic BALB/c mice, so although OK-432 treatment did increase the length of survival, all animals eventually died as a result of tumor growth. When peritoneal exudate cells (PEC), obtained on day 12 from OK-432-treated BAMC-1-bearing euthymic mice were evaluated for in vivo tumor neutralization activity, all mice receiving an i.p. injection of the admixture of the nonadherent PEC (1 X 10(7) cells) with BAMC-1 cells (1 X 10(5)) survived for more than 60 days. When the same nonadherent PEC (1 X 10(7) cells) were i.p. transferred adoptively 1 day after the inoculation of 1 X 10(5) BAMC-1 tumor cells, again all mice survived. When these in vivo active PEC were tested for cytotoxicity in vitro against fresh BAMC-1 tumor cells, natural killer (NK) sensitive syngeneic RL male 1, NK-sensitive allogeneic YAC-1 cells, NK-resistant syngeneic Meth-A cells, allogeneic tumor cells (EL4, B16, and P815) and xenogenic human cells, the PEC were found to be capable of lysing BAMC-1 tumor cells together with almost all of the other tumor cells, including NK-resistant cells. Nonadherent PEC contained at least two subpopulations of killer cells. One, directed to syngeneic BAMC-1 cells, was both Thy1.2 and asialo GM1 positive, and another, directed to allogeneic YAC-1 cells, was asialo GM1 positive but Thy1.2 negative. A cold target inhibition assay also suggested the presence of more than two subpopulations. These results indicate that T cells play a determined role in the immunotherapeutic effect of OK-432 on BALB/c mice bearing BAMC-1 tumor, although the participation of activated macrophages could not be excluded. The cells responsible for killing BAMC-1 and other tumor cells appearing in the PEC on day 12 were characterized as containing at least two kinds of lymphokine-activated killer cells.

Animals↗

Biological characteristics of a cold-adapted influenza A virus mutation residing on a polymerase gene.

The biological function of a cold-adapted (ca) mutation residing on the PB2 gene of an influenza A/Ann Arbor/6/60 (A/AA/6/60) ca variant virus in the viral replication cycle at 25 degrees C was studied. The viral polypeptide synthesis of A/AA/6/60 ca variant at 25 degrees C was evident approximately 6 hours earlier than the wild type (wt) virus and yielded twice as many products. The quantitative analysis of viral complementary RNA (cRNA), synthesized in the presence of cycloheximide, revealed that A/AA/6/60 ca variant and a single gene reassortant that contains only the PB2 gene of the ca variant with remaining genes of the wt virus produced equal amount of cRNA at 25 degrees and 33 degrees C, which was an amount approximately four fold greater than the wt virus' cRNA synthesized at 25 degrees C. These results strongly suggest that the ca mutation residing on the PB2 gene of A/AA/6/60 ca variant affects the messenger RNA synthesis at 25 degrees C in the primary transcription.

Cold Temperature↗

Patterns of polypeptide synthesis in human rotavirus infected cells.

Polypeptide analysis of three strains of human rotavirus (KUN, Wa and MO) were conducted using a hypertonic culture which suppressed host protein synthesis and unmasked rotavirus specific protein synthesis. As a result, eleven human rotavirus specific polypeptides (Vp 1--Vp 11) were detected by pulselabeling infected cells with [14C]-leucine. Among the 11 polypeptides, three polypeptides (Vp 7, Vp 10 and Vp 11) underwent post-translational processing, and two (Vp 7 and Vp 10) were glycosylated. Six polypeptides (Vp 1, 2, 3, 4, 6 and 7) were identified as viral structural proteins. Comparisons of three strains of different serotypes revealed that their polypeptide profiles differed from each other in electrophoretic mobility; in particular, profiles of the glycosylated polypeptide, Vp 7, were distinct among the three strains.

Animals↗

Inhibition of murine L cell interferon action by heparin.

Heparin added together with murine L cell interferon inhibited the development of antiviral activity in mouse L cells. When added after interferon treatment, heparin had no effect on antiviral activity. There was also no inhibition of interferon action in L cells treated with heparin before addition of interferon. On the other hand, heparin did not inhibit antiviral activities of human interferon alpha and beta. Since murine L cell interferon, but not human interferon alpha and beta, binds to a heparin affinity column and can be eluted with a solution of high salt, it is presumed that murine L cell interferon and heparin must interact with each other. The apparent interaction of heparin with murine L cell interferon was prevented by protamine, a drug that neutralizes heparin. Dextran sulfate inhibited murine L cell interferon action, but dextran and chondroitin sulfate A did not. These results suggests that heparin inhibited murine L cell interferon action by the binding via sulfate groups on its molecules. Heparin also inhibited antiviral activity of murine L cell interferon in mice infected with herpes simplex virus (+GC Miyama strain).

Animals↗

Further investigation on the mode of entry of human rotavirus into cells.

Entry of the KUN strain of human rotavirus into MA 104 cells was studied by electron microscopy. Double-shelled rotavirus particles attached to the cell membrane, and in the presence of trypsin their nucleic acids were expelled from the virus core into the cytoplasm through radial spaces between the capsomeres and the cell membrane pores formed after their attachment. This mechanism was considered to be analogous to those of phages.

Biological Transport↗

Binding and crosslinking of 125I-labeled recombinant human tumor necrosis factor to cell surface receptors.

Highly purified recombinant human tumor necrosis factor (TNF) (molecular mass determined as 17 kilodaltons (kDa) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and as 36 kDa by Sephadex G-100 gel chromatography) was labeled with 125I to a specific activity of 5 microCi/micrograms without appreciable loss of activity. The binding of 125I-TNF to eighteen human and twelve animal cell lines was examined. The binding varied considerably among different cell lines. In most cell lines, the binding was inhibited up to greater than 90% by the addition of a 100-fold excess of unlabeled TNF. Some human and mouse cell lines showed no significant binding above background levels, suggesting that these cell lines had no receptors for TNF. Among the TNF receptor-positive cell lines, there was no direct correlation between the level of specific TNF binding and the level of sensitivity to the cytotoxic or cytostatic effect of TNF. Some cell lines were sensitive to TNF, whereas others were not affected at all by TNF. The TNF receptor-negative cell lines were also resistant to TNF. Therefore, although the existence of TNF receptor seems to be necessary, it does not alone determine cellular sensitivity to TNF. Scatchard analysis of the binding data revealed that human HeLa S3 and THP-1 had about 50,000 and 10,000 receptors/cell with a dissociation constant (KD) of 0.3-0.5 nM, respectively. Similarly, mouse L-929 and L-M cells had about 5,000 receptors/cell with KD of 3-5 nM. 125I-TNF bound to HeLa S3 cells was rapidly internalized at 37 degrees C, presumably by receptor-mediated endocytosis, and degraded to acid-soluble products. The turnover of TNF receptors on HeLA S3 cells seemed to be rapid, since the level of specific binding quickly decreased after treatment with 100 micrograms/ml of cycloheximide at 37 degrees C with a half-life of about 1.5 h. The crosslinking of the cell-bound 125I-TNF with the use of disuccinimidyl suberate yielded a complex of 105 kDa for HeLa S3 and THP-1 cells, and a complex of 100 kDa for U937 cells. The crosslinking was completely inhibited by the addition of a 100-fold excess of unlabeled TNF. Assuming that the complex was due to a one-to-one association of the dimeric form of TNF (34 kDa) with the receptor, we estimated the molecular size of the human TNF receptor to be 71 kDa for HeLa S3 and THP-1, and 66 kDa for U937.

Animals↗