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Biomedical subjects

H Ushijima

Publications and source records attributed to H Ushijima.

At least 91 records · Page 5Linked to original sources
PubMed1994

The triaminopyridine flupirtine prevents cell death in rat cortical cells induced by N-methyl-D-aspartate and gp120 of HIV-1.

Flupirtine, a triaminopyridine derivative, is a non-opiate centrally acting analgesic agent with muscle relaxant properties. Now we show that this drug displays a potent cytoprotective effect on neurons (rat cortical cells) treated with (i) the excitatory amino acid N-methyl-D-aspartate (NMDA) or (ii) with the human immunodeficiency virus type 1 (HIV-1) coat protein gp120. In the absence of the drug the two agents cause a > 90% reduction of cell viability after a 18 h incubation. During this period the DNA in the cells undergoes fragmentation and shows a pattern which is typical for cell death. If the neurons were preincubated with flupirtine for 2 h and subsequently exposed to the cytotoxic agents an almost complete protection was achieved. The cytoprotective effect of flupirtine in vitro was significant (above 10 microM). Because flupirtine displays almost no clinical side effects and in light of the data presented here, flupirtine may be a promising drug also for the treatment of NMDA-mediated neurodegenerative disorders in general and for the treatment of AIDS-related encephalopathy in particular.

AIDS Dementia Complex↗
PubMed1994

Serotyping of human rotaviruses in the Tokyo area (1990-1993) by enzyme immunoassay with monoclonal antibodies and by reverse transcription and polymerase chain reaction amplification.

Serotyping of human rotavirus in the Tokyo area was conducted from 1990 to 1993 by enzyme immunoassay with monoclonal antibodies (EIA-MAbs) against VP7 and by reverse transcription and polymerase chain reaction (RT-PCR) amplification of the VP4 and VP7 genes. The results by EIA-MAbs were very similar to those obtained by RT-PCR. Evidence of intraserotypic variations was suggested because strains of undetermined serotypes were detected by either EIA-MAb or RT-PCR. This kind of study is required for vaccine development.

Antibodies, Monoclonal↗
PubMed1994

Detection of human immunodeficiency virus-1 nucleic acid on inactivated filter paper disks by polymerase chain reaction and microtiter plate assay.

Human immunodeficiency virus type 1 (HIV-1) in cultured cells, peripheral blood samples and sera were adsorbed on filter paper disks and inactivated by heat or ethanol. Two procedures, the polymerase chain reaction (PCR) and microtiter plate assay (HMPA) were used to detect the nucleic acid. The sensitivity after different heat treatments with nested PCR for HIV-1 DNA (or nested reverse transcription-PCR for HIV-1 RNA) was identical regardless of whether the samples were examined immediately or one month later. Inactivation by ethanol treatment resulted in a slight loss of sensitivity. The HMPA proved to be as reliable and specific as the conventional PCR technique. We conclude that the heat-treated filter paper disk assay is suitable for identifying HIV nucleic acid in clinical samples sent to the laboratory from a distance, e.g. in an envelope.

Base Sequence↗
PubMed1994

Synergistic effect of recombinant CD4-immunoglobulin in combination with azidothymidine, dideoxyinosine and 0.5 beta-monoclonal antibody on human immunodeficiency virus infection in vitro.

Data are presented which indicate that combinations of rCD4 immunoglobulin with azidothymidine, dideoxyinosine or 0.5 beta mouse monoclonal antibodies directed against the V3 region of HIV-1, were more effective in treatment of acute HIV infection in vitro than each compound alone. It is suggested that combination therapy with these compounds is more beneficial in treatment of HIV-infected patients than monotherapy, especially with respect to a reduction of the known side effects and the formation of resistant HIV strains after treatment with nucleoside analogues.

Anti-Bacterial Agents↗
PubMed1994

Detection and sequencing of rotavirus VP7 gene from human materials (stools, sera, cerebrospinal fluids, and throat swabs) by reverse transcription and PCR.

Human rotavirus RNAs from stool samples, sera, cerebrospinal fluids, and throat swabs of 15 children with rotavirus gastroenteritis were detected and serotyped by reverse transcription and PCR. The reverse transcription-PCR method may allow us to consider rotavirus infections in other parts of the body in addition to the gastrointestinal tract. Moreover, sequence analysis of the VP7 gene was performed on seven samples (one stool, two serum, three cerebrospinal fluid, and 1 throat swab sample). There were no appreciable differences in viral sequences between samples from cerebrospinal fluids, sera, or stools.

Acute Disease↗
PubMed1994

Application of typing by pulsed-field gel electrophoresis to the study of Clostridium difficile in a neonatal intensive care unit.

Pulsed-field gel electrophoresis (PFGE) analysis of restriction pattern polymorphism was applied to type Clostridium difficile isolated from neonates hospitalized in a neonatal intensive care unit, and the results were compared with those of immunoblot analysis. C. difficile was isolated from fecal specimens of 41 (61%) of 67 neonates during a 5-month investigation. All of these neonates were asymptomatic. Fifty-five C. difficile isolates from 32 patients were analyzed by PFGE after digestion with SmaI and SacII endonucleases and by immunoblotting with 10 different antisera. Fifty-three of 55 isolates from 30 patients were identical by PFGE analysis after SmaI and SacII digestion and immunoblot analysis. Two isolates were different from each other and from the epidemic group by both PFGE and immunoblot analysis. All 53 epidemic isolates were nontoxigenic, while the two remaining isolates were toxigenic. These results suggest that nosocomial spread of nontoxigenic C. difficile infection in the neonatal intensive care unit and suggest that both PFGE and immunoblot are powerful typing tools for the epidemiological study of C. difficile.

Antibodies, Bacterial↗
PubMed1994

[Effects of Celosia argentea and Cucurbita moschata extracts on anti-DNP IgE antibody production in mice].

We have already reported that the Perilla frutescens extract (PFE) suppressed anti-DNA IgE antibody production in mice. In this study, we prepared extracts of Celosia argentea L. (CAE) and Cucurbita moschata Duch (CME), which are Chinese herbal medicines like Perilla frutescens, and examined the effects on anti-DNP antibody responses in mice. To examine the effects of CAE & CME on primary antibody responses, CAE & CME were intraperitoneally injected the day before primary immunization of DNP-ovalbumin. Anti-DNP antibody production was markedly suppressed. Then, we examined the effects on secondary antibody responses. CEA & CME were injected only the day before secondary immunization. Anti-DNP IgE production was markedly suppressed, but IgG responses were not affected. It was also found that mitogenic activity occurred in CAE & CME dose dependently in vitro. These effects of CAE & CME were superior to that of PFE. These results suggest that CAE & CME may be more useful than PFE for the suppression of IgE antibody in certain allergic disorders.

Animals↗
PubMed1993

Cytoprotective effect of NMDA receptor antagonists on prion protein (PrionSc)-induced toxicity in rat cortical cell cultures.

Rat cortical cells were incubated with the Scrapie prion protein, PrionSc. At concentrations of 3 ng/ml of PrionSc and higher, the viability of the cells decreased significantly after a 12-h incubation period. Simultaneously, the degree of DNA fragmentation increased. In control experiments with antibodies against PrionSc, PrionSc lost its deleterious effect on neurons. PrionSc did not affect the viability of astrocytes. Drugs known to block NMDA receptor channels, such as memantine (1-amino-3,5-dimethyl-adamantane) (Mem), its analogue 1-N-methylamino-3,5-dimethyl-adamantane as well as (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) prevented the effect of PrionSc. Production of PrionSc in the Scrapie prion-infected subclone of N2 a cells (ScN2 a cells) was not affected by memantine. We conclude that antagonists of the NMDA receptor-channel complex (i) abolish the PrionSc-induced neuronal injury in vitro, and (ii) display no influence on the synthesis and/or the processing of PrionSc.

Animals↗
PubMed1993

Genetic variation in VP7 gene of human rotavirus serotype 1 (G1 type) isolated in Japan and China.

Sequence analysis of the gene encoding the major neutralization glycoprotein (VP7) was performed on 12 human isolates of serotype 1 of rotavirus in Japan and China. They were examined for genetic variations among serotype 1 isolates. Comparative studies of their nucleotide and deduced amino acid sequences between the 12 isolates and the Wa strain revealed an overall homology of more than 92 and 96%, respectively. Higher degrees of homologies were observed between Wa and 2 strains (K1 and K2) in Tokyo, 1979-1980, than between Wa and recent isolated strains in Tokyo and in China. In our isolates, a total of 16 amino acid residues frequently converted to another amino acid. Six amino acid residues belonging to the major neutralizing epitope regions (B, D, and E in this communication) frequently converted. From these data three subtypes (subtypes A, B, and intermediate) were suggested to be divided. Whether these differences are an important mechanism in the epidemiology of rotaviruses requires further investigation.

Amino Acid Sequence↗
PubMed1993

Evidence for age-dependent impairment of antiviral 2',5'-oligoadenylate synthetase/ribonuclease L-system in tissues of rat.

The 2',5'-oligoadenylate system (2-5A system) has an essential role in the establishment of the antiviral state of cells exposed to virus infection. The effects of 2-5A are mediated by a 2-5A-dependent ribonuclease (RNase L) which cleaves viral RNA. A study of 2-5A metabolism in different tissues of rats of different age (newborn: 1-day-old; young adult: 2- to 3-month-old; middle-aged adult: 12-month-old; and old: 32- to 33-month-old) revealed that the activities of the 2-5A metabolic enzymes alter during aging and development. We demonstrate that soluble 2-5A synthetase activity strongly increases after birth, reaching maximal levels in young adult and middle-aged adult animals and then significantly decreases with age; the age-dependent decrease was found also for the nuclear matrix-associated enzyme. In contrast, the activity of 2',3'-exoribonuclease which inactivates 2-5A increases by 3-fold with age. The decrease in 2-5A synthetase activity and increase in 2-5A nuclease activity were found to result in a decrease in the cellular 2-5A content with age. The RNase L which is activated by 2-5A also changes age-dependently. The amount and activity of this enzyme were determined in cross-linking experiments, in nitrocellulose binding assays and in the ribosomal RNA cleavage assay. The livers of old rats displayed a 5- to 6-fold decrease in RNase L activity compared to the adult animal groups, whilst the amount of the enzyme did not change significantly during aging with the exception of a drop by 30% in the nuclear matrix fraction. From these results we conclude that the antiviral activity of the 2-5A system is impaired in old cells with the consequences that virus production cannot be efficiently suppressed.

2',5'-Oligoadenylate Synthetase↗
PubMed1993

Mode of action of the anti-AIDS compound poly(I).poly(C12U) (Ampligen): activator of 2',5'-oligoadenylate synthetase and double-stranded RNA-dependent kinase.

The mismatched double-stranded RNA (dsRNA), poly(I).poly(C12U), also termed Ampligen, exhibits a strong antiviral and cytoprotective effect on cells (human T-lymphoblastoid CEM cells and human T-cell line H9) infected with the human immunodeficiency virus type 1 (HIV-1). Untreated H9 cells infected with HIV-1 start to release the virus 3 days post-infection, while in the presence of 40 micrograms/ml (80 micrograms/ml) of poly(I).poly(C12U) the onset of virus production and release is retarded and does not occur before day 5 (day 6). We demonstrate that poly(I).poly(C12U) markedly extends the duration of the transient increase of 2',5'-oligoadenylate (2-5A) synthetase mRNA level and activity preceding virus production after infection of cells with HIV-1. Treatment of HeLa cells with poly(I).poly(C12U) was found to cause a significant increase in total (activated plus latent) 2-5A synthetase activity; no evidence was obtained that the level of latent (nonactivated) 2-5A synthetase is changed in cells treated with dsRNA plus interferon (IFN). Poly(I).poly(C12U) is able to bind and to activate 2-5A synthetase(s) from HeLa cell extracts. Addition of poly(I).poly(C12U) to HeLa cell extracts results in production of longer 2-5A oligomers (> or = 3 adenylate residues), which are better activators of RNase L. Both free and immobilized poly(I).poly(C12U) also bind to the dsRNA-dependent protein kinase (p68 kinase), resulting in autophosphorylation of the enzyme. Activation of the kinase by the free RNA occurs within a limited concentration range (10(-7) to 10(-6) grams/ml). Addition of HIV-1 Tat protein does not affect binding and activation of p68 kinase to poly(I).poly(C12U)-cellulose but strongly reduces the binding of the kinase to immobilized TAR RNA of HIV-1. We conclude that poly(I).poly(C12U) may antagonize Tat-mediated down-regulation of dsRNA-dependent enzymes.

2',5'-Oligoadenylate Synthetase↗
PubMed1993

[Seroepidemiological study of human rotavirus in northern part of Tokyo from 1990 to 1992 by using reverse transcription-polymerase chain reaction].

A seroepidemiological study of rotavirus was conducted in the northern part of Tokyo from 1990 to 1992 by using reverse transcription-polymerase chain reaction (RT-PCR). G1 and G3 types were detected in the winter between 1990 and 1991, however G1 type was appeared mainly in the winter between 1991 and 1992. G3 type was observed as the main type during the winter in the 10 year survey in the Tokyo area for the first time. RT-PCR was useful in the seroepidemiological studies of rotavirus infection.

Base Sequence↗
PubMed1993

Characterization of cells of the myeloid-monocytic lineage (ML-1, HL-60, THP-1, U-937) chronically infected with the human immunodeficiency virus-1.

The myeloid-monocytic cells ML-1, HL-60, THP-1 and U-937 were chronically infected (for more than 2 years) with the lymphotropic HIV-1 strain HTLV-IIIB. Reinfection experiments revealed that viruses obtained from chronically infected ML-1/HIV-1 and HL-60/HIV-1 cells show a low infectivity if tested with uninfected ML-1 and HL-60 cells in contrast to virus preparations from chronically infected THP-1/HIV-1 and U-937/HIV-1 with their corresponding uninfected cell lines. Analyses of selected cell surface markers showed a differential expression of CD4, CD8, CD11c, CD14, CD15, CD20, HLA-DR and HLA-DQ in non- or chronically infected cells. During chronical infection, the myeloid-monocytic cells lost their reactivity with peroxidase and esterase. In chronically infected cells, the steady-state levels for TNF-alpha mRNA remained unchanged while those for IL-6 decreased. The half-lives of transcripts of both TNF-alpha (t1/2: 70 min) and IL-6 (t1/2: 100 min) were nearly the same in uninfected and chronically infected HL-60 cells.

Bone Marrow↗
PubMed1993

Assessment of myometrial invasion by endometrial carcinoma: transvaginal sonography vs contrast-enhanced MR imaging.

OBJECTIVE: A prospective study was designed to compare transvaginal sonography with contrast-enhanced MR imaging to determine preoperatively the depth of myometrial invasion in patients with early-stage endometrial carcinoma. SUBJECTS AND METHODS: In 40 patients, findings on transvaginal sonograms, unenhanced T2-weighted MR images, and contrast-enhanced T1-weighted Mr images were compared with histologic findings. The depth of myometrial invasion was classified as stage E (tumor limited to endometrium, n = 12), stage S (superficial invasion: tumor invades up to 50% of the myometrium, n = 15), or stage D (deep invasion: tumor invades more than 50% of the myometrium, n = 13). RESULTS: Findings on transvaginal sonograms were accurate in 27 of 40 patients (accuracy, 68%); the depth of invasion was overestimated in five patients and underestimated in eight patients. The results of unenhanced T2-weighted MR images were accurate in 27 patients (accuracy, 68%), with four overestimations and nine underestimations. The results of contrast-enhanced T1-weighted MR images were accurate in 34 patients (accuracy, 85%), with five underestimations and one overestimation. In the assessment of each stage of myometrial invasion, the sensitivity and specificity of contrast-enhanced T1-weighted imaging were higher than those of T2-weighted MR imaging and transvaginal sonography. The false-positive diagnoses based on transvaginal sonograms and T2-weighted images, respectively, involved polypoid tumors (n = 4 and 2), distension of the endometrial cavity by pyometra (n = 2 and 1), the presence of myoma (n = 2 and 1), atrophy of the myometrium (n = 1 and 0), and poor tumor/myometrium contrast (n = 0 and 2). On contrast-enhanced MR images, accuracy was influenced only in a case of polypoid tumor, because tumor, endometrial cavity, and myometrium were clearly distinguished and residual myometrium was clearly visualized. With all imaging techniques, false-negative diagnoses were caused mainly by tumors with superficially spreading growth or microscopic invasion. With transvaginal sonography, infiltrative tumor also tended to be understaged (n = 3). CONCLUSION: Contrast-enhanced MR imaging is significantly superior to transvaginal sonography and unenhanced T2-weighted MR imaging for detecting myometrial invasion.

Adult↗
PubMed1993

HIV-1 gp120 and NMDA induce protein kinase C translocation differentially in rat primary neuronal cultures.

Exposure of rat cortical neurons to the human immunodeficiency virus type 1 (HIV-1) coat protein gp120 in vitro causes a rise in the intracellular Ca2+ level and a subsequent translocation of protein kinase C (PKC) from the cytosol to the membrane. Such a translocation persists for at least 2 h, but only in cultures with media not depleted of endogenous glutamate. Enzymatic degradation of glutamate in the medium by the enzyme glutamate-pyruvate transaminase (GPT) abolishes the long-lasting effect of gp120 on the association state of PKC; under this incubation condition the translocation period is < 1 h. Memantine and the ganglioside GM1 prevent N-methyl D-aspartate receptor-mediated long-term translocation of PKC and gp120-mediated neurotoxicity (in the absence of GPT); they have no effect on short-term translocation of PKC. We suggest that gp120-caused neuronal death involves an indirect sensitization step of the NMDA receptors, which ultimately induces neuronal death.

Animals↗
PubMed1993

[AIDS virus].

A Japanese child case of subacute progressive encephalopathy was presented. Not only the pathological findings of HIV growth in microglias, astrocytes and macrophages in the central nervous system, but also the pathobiological findings of neuronal apoptosis were shown as etiologies of HIV encephalopathy. Epidemiology, diagnosis, prophylaxis, fetomaternal transmission and embryopathy were discussed briefly.

AIDS Dementia Complex↗
PubMed1992

Association of AUUUA-binding protein with A+U-rich mRNA during nucleo-cytoplasmic transport.

Resealed nuclear envelope (NE) vesicles from rat liver containing entrapped exogenous RNA were used to study the effect of adenosine+uridine binding factor (AUBF), present in cytosolic cell extracts, on ATP-dependent transport of A+U-rich RNA (AU+RNA) and A+U-free RNA (AU-RNA) across the NE. This factor specifically binds to A+U-rich sequences present in the 3' untranslated regions of lymphokine and cytokine mRNAs, containing overlapping AUUUA boxes (granulocyte-macrophage colony stimulating factor, interleukin-3). Addition of AUBF to the extravesicular compartment markedly increased the efflux of the in vitro transcribed, capped and polyadenylated AU+ RNAs. Export of entrapped AU- control RNA, such as beta-globin RNA, was not affected by AUBF, in contrast to chimeric AU+ beta-globin RNA containing the A+U-rich sequence of human interferon-alpha mRNA (6 reiterated AUUUA motifs). Competition experiments revealed that AUBF enhances the affinity of poly(A)-containing AU+ RNAs to the NE poly(A)-binding component (poly(A)-recognizing mRNA carrier p106), and thereby accelerates nuclear export of these RNAs. We could demonstrate that AUBF added to the extravesicular space forms stable complexes with polyadenylated AU+ RNA with relative molecular masses of about 45,000, 62,000 and 70,000 inside the vesicles or during ATP-dependent export. In addition we determined that AUBF may affect mRNA stability by protecting A+U-rich RNA against degradation by trans-acting, nuclear matrix-associated and A+U-specific endoribonuclease V.

Adenosine↗