Search PubMed⌕ Search

Biomedical subjects

H Ushijima

Publications and source records attributed to H Ushijima.

At least 73 records · Page 4Linked to original sources
PubMed1997

Effect of flupirtine on Bcl-2 and glutathione level in neuronal cells treated in vitro with the prion protein fragment (PrP106-126).

Flupirtine, trade name Katadolon, is a centrally acting nonopioid analgesic that has recently been found to display cytoprotective activity in vitro and in vivo on neurons induced to undergo apoptosis. This report shows that the PrP106-126 fragment of the prion protein, which is the likely etiological agent for a series of encephalopathies, is toxic to cortical neurons in vitro. Simultaneously, PrP106-126 influences the molecular GSH content and the bcl-2 expression in neurons. Significant toxicity (32% reduction in cell viability) was observed at a concentration of 50 microM of the peptide after 9 days of incubation, while at higher concentrations toxicity increased to 70%. Neurotoxicity was greatly reduced following coincubation with 1 to 3 microg/ml flupirtine. Concomitant with PrP106-126-mediated cytotoxicity, glutathione (GSH) content fell by > 70% with respect to untreated controls. This decrease in GSH level was strongly blocked by flupirtine under incubation conditions that reduce cell toxicity. In addition to normalizing GSH content, flupirtine induced the expression of the anti-apoptotically acting proto-oncogene bcl-2. Based on these in vitro data and on the favorable pharmacokinetic profile of the drug, we strongly suggest that flupirtine may prove useful for treatment of patients with prion disease.

Amino Acid Sequence↗
PubMed1997

Genetic analysis of the capsid region of human astrovirus serotype 3 isolated in Japan.

The total capsid region of astrovirus serotype 3 was analyzed using five isolates including four from Japan and one from the United Kingdom. The nucleic acid and deduced amino acid sequences in the region were homologous (over 97%). However, the sequences of serotype 3 were different from those of serotypes 1, 2, 4, 5, 6 and 8, especially in the C terminus.

Amino Acid Sequence↗
PubMed1997

Genetic variation in the VP7 gene of human rotavirus serotype 3 (G3 type) isolated in China and Japan.

Sequence analysis of the VP7 gene was performed on twenty-one human isolates of serotype 3 related-rotavirus in China and Japan. The five Chinese isolates were found to be not similar to the 16 Japanese isolates and to SA11 (simian rotavirus). The Chinese isolates, especially CHW2 and CH-32, were different from the major serotype 3 human isolates. AU-1 and 02/92 which previously showed a wider spacing between RNA segments 10 and 11 by RNA polyacrylamide gel electrophoretic analysis, were more closely related to each other and could be differentiated from the other Chinese and Japanese isolates. For these reasons, serotype 3 viruses were considered to be intraserotypically more heterologous than serotype 1, 2 and 4 viruses.

Amino Acid Sequence↗
PubMed1996

Neurotoxicity in rat cortical cells caused by N-methyl-D-aspartate (NMDA) and gp120 of HIV-1: induction and pharmacological intervention.

Incubation of highly enriched neurons from rat cerebral cortex with the human immunodeficiency virus type 1 (HIV-1) coat protein gp120 for 18 h results in fragmentation of DNA at internucleosomal linkers, a feature of apoptosis. We report that neurons respond to exposure to gp120 with an increased release of arachidonic acid via activation of phospholipase A2. This process is not inhibited by antagonists of the N-methyl-D-aspartate (NMDA) receptor channels. To investigate the influence of arachidonic acid on the sensitivity of NMDA receptor towards its against, low concentrations of NMDA were coadministered with arachidonic acid. Under these conditions the NMDA-mediated cytotoxicity was enhanced. We conclude that gp120 causes an activation of phospholipase A2, resulting in an increased release of arachidonic acid which in turn sensitizes the NMDA receptor. Two compounds were found to act cytoprotectively against the deleterious effect caused by gp120 on neurons: Memantine [1-amino-3,5-dimethyladamantane] and Flupirtine [2-amino-3-ethoxycarbonylamino-6-(4-fluoro-benzyl-amino)-pyridine maleate]. Both compounds have been found to display a potent cytoprotective effect on neurons treated with the excitatory amino acid NMDA or with the human immunodeficiency virus type 1 (HIV-1) coat protein gp120. The NMDA antagonist Memantine, a drug currently used in the therapy of spasticity and Parkinson's disease, prevented the effects of gp120 at micromolar concentrations. Flupirtine was previously found to be a centrally acting, nonopiate analgesic agent which additionally possesses anticonvulsant and muscle-relaxant activity at doses similar to those producing analgesia. The cytoprotective effect of Flupirtine in vitro was significant (above 10 microM). Considering the fact that both Memantine and Flupirtine display almost no clinical side effects, these drugs may prove useful both in preventing primary infection of brain cells with the HIV virus, as well as in treating the neurological disorders often associated with the immunodeficiency syndrome such as AIDS-related dementia.

Aminopyridines↗
PubMed1996

Detection and sequencing of Norwalk-like viruses from stool samples in Japan using reverse transcription-polymerase chain reaction amplification.

Norwalk-like viruses were detected in Japan in 12% (26/209) of patients with nonbacteria and nonrotavirus gastroenteritis in an outpatient clinic of a hospital from 1991 to 1994 by reverse transcription-polymerase chain reaction. They were also present in 7% (26/378) of total samples including those from rotavirus-positive gastroenteritis patients. In addition, the viruses were recovered in samples from 15 of 17 patients which were collected during outbreaks of gastroenteritis in various places in Japan by the same method. The DNA sequence of the polymerase region from patients at the hospital (sporadic cases) showed that two subgenogroups, similar to UK1-6 in genogroup G1 and to UK1-1 in genogroup G2 (Ando et al, J Clin Microbiol, 1995, 33: 64-71) exist in Japan. The latter was more frequently found.

Base Sequence↗
PubMed1996

Detection of human immunodeficiency virus-1 DNA, RNA and antibody, and occult blood in inactivated saliva: availability of the filter paper disk method.

Eighty three samples of saliva were collected from 60 subjects who were asymptomatic carriers of AIDS related complex (ARC) and AIDS. They included hemophiliacs, homosexuals and heterosexuals. Occult blood, human immunodeficiency virus-1 (HIV-1) antibody and DNA were assayed after heat treatment at 56 degrees C by strip method, particle agglutination and polymerase chain reaction (PCR), respectively. HIV-1 RNA was assayed by reverse transcription (RT)-PCR after heat treatment at 56 degrees C or 90 degrees C, or after application to filter paper disks with drying and heat treatment at 90 degrees C. Positive results were found in 53% (occult blood), 73% (HIV-1 antibody), 23% (HIV-1 DNA, 56 degrees C), 34% (HIV-1 RNA, 56 degrees C), 33% (HIV-1 RNA, 90 degrees C) and 25% (HIV-1 RNA, 90 degrees C, filter paper disk), respectively. The results did not depend on the stage of the disease or the route of infection. Other studies have reported the use of the filter paper disk method to detect antibodies against HIV and HIV genomes in blood samples. The present study demonstrated that it could also be used for the detection of HIV genomes in saliva samples.

AIDS Serodiagnosis↗
PubMed1996

[Diagnosis and clinical manifestations of diarrheal virus infections in Maizuru area from 1991 to 1994--especially focused on small round structured viruses].

Rotavirus (44.7%), adenovirus (5.6%), small round structured viruses such as astrovirus (9.8%) and Norwalk like virus (6.9%) were detected by latex agglutination and reverse transcription polymerase chain reaction amplification from 378 stool samples in an outpatient clinic of Pediatrics in Maizuru area from 1991 to 1994. 70.0% were found from 6 months to 2 years old and 91.0% were detected from January to April. Serotype 1 astrovirus and group 2 Norwalk like virus were mainly found in all serotypes in each virus. Diarrhea, vomiting, nausea, fever, cough and rhinorrhea, and severity of diseases were examined in each case. Fever is significantly found in patients with rotavirus. Sporadic cases with small round structured viruses were recognized in the outpatient clinic of pediatrics.

Adenoviridae↗
PubMed1996

[Detection and genotyping of astroviruses by RT-PCR and sequencing].

Three primer pairs, AV244Mon and 82b, AV-15Gr and AV-12Gr, and Beg and End, were used for the detection of standard astroviruses (serotype 1 to serotype 7) in cell culture and astroviruses isolated from 89 diarrheal stool specimens negative for pathogenic bacteria, rotavirus and adenovirus by the reverse transcription-polymerase chain reaction (RT-PCR). All the standard strains and two isolates were detected by primer pairs AV244Mon and 82b, and AV-15Gr and AV-12Gr. All serotypes except serotype 4 were detected by the primer pair Beg and End. The molecular sizes of the RT-PCR products obtained by Beg and End were almost the same among the different serotypes except serotype 6. Sequence analyses of the nucleic acid in the regions between the primer pairs AV244Mon and 82b, and between Beg and End from PCR products of the standard strains and from the isolates of the two stool specimens revealed that each serotype had a unique sequence. These results indicate that the RT-PCR is useful for detecting and genotyping astroviruses.

Base Sequence↗
PubMed1995

Expression of nuclear lectin carbohydrate-binding protein 35 in human immunodeficiency virus type 1-infected Molt-3 cells.

The nuclear carbohydrate-binding protein 35 (CBP35), a beta-galactoside-specific lectin with an M(r) of 35,000, has been identified in nuclear ribonucleoprotein complexes (RNPs) from a variety of mammalian tissues and cells. Here we determined that the expression of CBP35 mRNA greatly increases after infection of Molt-3 cells with human immunodeficiency virus type 1 (HIV-1), concomitantly with the onset of expression of the viral regulatory gene tat, and then declines. The increase in CBP35 mRNA level results in an enhanced synthesis of CBP35, as evidenced in nitrocellulose filter binding assay using radiolabeled, sugar-specific neoglycoprotein. Immunoblotting experiments showed that CBP35 is present in the 40S heterogeneous nuclear RNP complex from HIV-1-infected Molt-3 cells. CBP35 could also be detected using a novel photoreactive alpha-D-galactose probe designed for the specific detection of CBP.

Antigens, Differentiation↗
PubMed1995

Exposure to gp120 of HIV-1 induces an increased release of arachidonic acid in rat primary neuronal cell culture followed by NMDA receptor-mediated neurotoxicity.

After incubation of highly enriched neurons from rat cerebral cortex with the HIV-1 coat protein gp120 for 18 h, cells showed fragmentation of DNA at internucleosomal linkers followed by NMDA receptor-mediated neurotoxicity. We report that in response to exposure to gp120 cells react with an increased release of arachidonic acid (AA) via activation of phospholipase A2. This process was not inhibited by NMDA receptor antagonists. To investigate the role of AA on the sensitivity of the NMDA receptor towards its agonist, low concentrations of NMDA were co-administered with AA. This condition enhanced the NMDA-mediated cytotoxicity. Administration of mepacrine reduced cytotoxicity caused by gp120. We conclude that gp120 causes an activation of phospholipase A2, resulting in the increased release of AA, which may in turn sensitize the NMDA receptor.

Animals↗
PubMed1995

Flupirtine partially prevents neuronal injury induced by prion protein fragment and lead acetate.

Flupirtine belongs to the class of triaminopyridines and is successfully applied clinically as a non-opiate analgesic drug with additional muscle relaxant properties. Recently it was reported that flupirtine acts like an antagonist of the N-methyl-D-aspartate (NMDA) receptor complex in neuronal cells both in vitro and in vivo. Here we have used primary cortical cells from rat embryos to demonstrate that this compound is also neuroprotective against the toxic effects caused by the prion agent PrPSc and lead acetate (Pb). These two agents display pleiotropic effects on neurons, which include activation of the NMDA receptor complex. At concentrations above 30 microM the toxic-peptide fragment of PrPSc causes apoptotic fragmentation of DNA and is consequently neurotoxic. Pb is neurotoxic at concentrations above 10 microM. Co-administration of flupirtine (10 microM) with either of these agents resulted in reduced neurotoxicity. These data indicate that the cytoprotective effect of flupirtine is measurable in vitro against these noxious agents which show their effects, including modulation of the NMDA receptor complex, pleiotropically.

Amino Acid Sequence↗
PubMed1995

Sensitive detection of group A rotaviruses by immunomagnetic separation and reverse transcription-polymerase chain reaction.

An immunomagnetic separation (IMS) method was developed for concentrating rotaviruses from environmental samples, as well as a reverse transcription-polymerase chain reaction (RT-PCR) for the sensitive and specific detection of group A rotaviruses. Magnetic beads were coated with monoclonal antibodies directed against the group-specific, inner capsid protein (VP6) and subsequently used to capture and purify the virus with the help of a magnet. The genome was made available for RT by heat-disrupting the viral particles. A single 40-cycle PCR was as sensitive as a nested PCR, both detecting 0.005 PFU of the Wa strain, corresponding to approximately 5 particles as indicated by EM. The nested PCR was positive for all the group A strains tested, but negative for group C rotaviruses and other RNA viruses. The IMS-RT-PCR method functioned satisfactorily with virus seeded out in fresh water samples; with sea water, the IMS removed most, but not all, inhibiting activity.

Antigens, Viral↗
PubMed1995

Passive protection against rotavirus-induced diarrhea of mouse pups born to and nursed by dams fed Bifidobacterium breve YIT4064.

Mouse pups born to and nursed by dams fed Bifidobacterium breve YIT4064 and immunized orally with rotavirus were more strongly protected against rotavirus-induced diarrhea than those born to and nursed by dams immunized with rotavirus only. The level of antirotavirus IgA in milk of dams fed B. breve YIT4064 and immunized orally with rotavirus was significantly higher than that of dams immunized with rotavirus only. The antirotavirus IgA level in feces of dams immunized orally with rotavirus was also increased by oral administration of B. breve YIT4064. These findings demonstrate that oral administration of B. breve YIT4064 enhanced antigen-specific IgA antibody in the mammary gland and in the intestine. Oral administration of B. breve YIT4064 may enhance antigen-specific IgA antibody against various pathogenic antigens taken orally and induce protection against infections in various mucosal tissues.

Age Factors↗
PubMed1995

Detection of astroviruses from stool samples in Japan using reverse transcription and polymerase chain reaction amplification.

We developed a reverse transcription and polymerase chain reaction (RT-PCR) method for detecting astrovirus serotypes 1, 2, 3, 5, 6 and 7 (but not serotype 4). Furthermore, we developed the specific primers for detecting serotypes 1 and 2, the most predominant serotypes in the world. Sensitivity of the first PCR with serotype common primers was about 10 times higher than that of enzyme immunoassay with monoclonal antibody (EIA-MAb). Sensitivity of the second PCR with the serotype-specific primers was even higher. The RT-PCR method was useful for detecting astroviruses from clinical samples, especially serotypes 1 and 2.

Base Sequence↗
PubMed1995

Genetic variation in VP7 gene of human rotavirus serotype 2 (G2 type) isolated in Japan, China, and Pakistan.

Sequence analysis of the gene encoding the major neutralization glycoprotein (VP7) was performed on sixteen human isolates of serotype 2 of rotavirus in Japan, China, and Pakistan and their genetic variations were examined. Comparative studies of their nucleotide and deduced amino acid sequences between the sixteen isolates and the HU5 strain revealed an overall homology of more than 94%. A higher degree of homology in nucleotides was observed among the sixteen isolates than between HU5 and the isolates. A total of thirteen amino acid residues frequently converted to another amino acid. Out of the thirteen, five amino acid residues belonging to the major neutralizing epitope regions (C, E, and F in this communication) converted frequently. From the amino acid sequences three subtypes, subtype 1, subtype 2, and intermediate, were suggested to be classified as previously reported for serotype 1 (Xin et al, Virology, 1993, 197: 813-816).

Amino Acid Sequence↗