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T Nakaya

Publications and source records attributed to T Nakaya.

At least 91 records · Page 5Linked to original sources
PubMed1997

[Demonstration on Borna disease virus in patients with chronic fatigue syndrome].

Chronic fatigue syndrome (CFS), a recently named heterogeneous disorder, is an illness of unknown etiology. The association between CFS and several viral infection has been suggested. Here, we centered on the possible link between CFS and Borna disease virus (BDV) infection. BDV is a neurotropic, nonsegmented negative-strand (NNS) RNA virus. Recent epidemiological data have suggested that BDV may be closely associated with depression and schizophrenia in humans. In Japanese patients with CFS, the prevalence of BDV infection was 34% (30/89) and 12% (7/57) by immunoblotting and PCR analysis, respectively. Furthermore, anti-BDV antibodies and BDV RNA were detected in a family cluster with CFS. These results suggested that this virus contributes to or initiates CFS, although the single etiologic role of BDV is unlikely.

Adult↗
PubMed1996

Growth dominance of a revertant virus generated during in vitro serial passage of nef frameshift mutant of HIV-1.

We prepared a series of nef mutant HIV-1 with a frameshift mutation at the Xho I site by up to 50 serial transfers into MT-4 cells. Here, we studied revertants. Immunofluorescence using an anti-Nef monoclonal antibody revealed that cells first became Nef antigen-positive at the 23rd passage. The percentage of Nef antigen-positive cells gradually increased and reached almost 100% by the 27th passage. The sequence of the provirus in the cells supported the generation of a revertant. This revertant mutated at the site immediately after the initially introduced frameshift mutation. This resulted in the substitution of only three amino acids and the insertion of two, which restored the proline-rich domain, a conserved region believed essential to viral replication, at the middle of Nef. Thus, the growth dominance of the revertant virus, compared with the original nef mutant, was directly demonstrated in vitro using serial passages consisting of mixed HIV-1 populations in a single cell.

Amino Acid Sequence↗
PubMed1996

Demonstration of Borna disease virus RNA in peripheral blood mononuclear cells derived from Japanese patients with chronic fatigue syndrome.

CFS, a recently named heterogeneous disorder, is an illness of unknown etiology. The association of CFS with viral infections has been suggested. A common association between CFS and several viruses examined has not been confirmed. Here, we centered on the possible link between CFS and BDV infection. By nested RT-PCR followed by hybridization, BDV RNA was demonstrated as a clear signal in PBMCs in 3 out of 25 CFS patients. The amplified cDNA fragments were cloned and sequenced. A total of 16 clones were studied. Intra-patients divergencies of the p24 were 2-9%, 3-20%, and 3-11% in the deduced amino acids. Inter-patient divergencies among the 16 clones were 3-24%. Antibodies to recombinant BDV p24 protein were detected in 6 CFS patients including one carrying BDV RNA. Overall, these gave the prevalence of 32% (8/25) in Japanese CFS patients, suggesting that Japanese CFS is highly associated with active infection of BDV, or a related agent.

Adult↗
PubMed1996

High susceptibility of U937-derived subclones to human immunodeficiency virus type 1 infection correlates with accumulation of unintegrated circular viral DNA.

Our previous report showed that U937-derived subclones were differentiated into at least three types (high, middle, and low types), even in the subclones expressing similar levels of surface CD4, in terms of the kinetics of the appearance of viral antigens and virus production after infection with human immunodeficiency virus type 1 (HIV-1). Here we showed the evidence that high susceptibility to HIV-1 infection, which was confirmed by the profound expression of viral messages and antigens, was exclusively associated with a high number of the unintegrated extrachromosomal form of viral DNA, but not with the amounts of adsorbed virus RNA nor those of integrated DNA form. The difference in the amounts of extrachromosomal form of viral DNA was also observed in the culture with 3'-azido-3'-deoxythymidine (AZT), indicating that the susceptibility is essentially unrelated to multiple infection events. Thus, the susceptibility of U937-derived subclones to HIV-1 infection seems to be affected by the occurrence of specific events involved in the accumulation of unintegrated viral DNA after viral adsorption.

DNA, Circular↗
PubMed1996

Borna disease virus RNA in peripheral blood mononuclear cells obtained from healthy dairy cattle.

We examined natural infection of Borna disease virus (BDV) in 74 healthy dairy cattle in Japan. The seroprevalence determined using recombinant BDV p24 protein was 20.3%. The prevalence of BDV RNA in peripheral blood mononuclear cells (PBMCs) determined by polymerase chain reaction for p24 was 10.8%. Cell fraction of the PBMCs revealed the presence of BDV RNA in the T cell-enriched fraction. Thus, BDV infection is widespread even among healthy cattle.

Animals↗
PubMed1996

Synthesis and blood compatibility evaluation of segmented polyurethanes based on cholesterol and phosphatidylcholine analogous moieties.

New segmented polyurethanes based on cholesterol and phosphatidylcholine analogous moieties were synthesized. The soft segments used in this study were the poly(butadiene), poly(isoprene) or hydrogenated poly(isoprene) glycols; the hard segments of these segmented polyurethanes were composed of 4,4'-methylenediphenyl diisocyanate, 2-[bis(2-hydroxyethyl)methylammonio]ethyl 5-cholesten-3 beta-yl phosphate and 1,4-butanediol. The blood compatibilities of synthesized segmented polyurethanes were evaluated by platelet-rich plasma contact studies and scanning electron microscopy observation using glass as the reference. The results show that the blood compatibilities of the synthesized segmented polyurethanes have great difference between the glass contact side and air exposed side for the same cast films. Generally, the hydrogenated poly(isoprene)-based segmented polyurethane is the best surface in terms of platelet adhesion, and the morphology of adhered platelets undergoes the lowest degree of variation among the segmented polyurethanes investigated in this study.

Biocompatible Materials↗
PubMed1996

Varied prevalence of Borna disease virus infection in Arabic, thoroughbred and their cross-bred horses in Iran.

Borna disease virus (BDV) naturally infects horses and sheep and induces progressive poliomeningoencephalomyelitis. Here, BDV recombinant proteins of the first open reading frame (ORF-I; coding for p40 nucleoprotein) and the second ORF-II (coding for p24 polymerase cofactor) were immunoblotted with plasma derived from 72 healthy (28 Arabic, 17 thoroughbred and 27 cross-bred) race horses at Tehran in Iran to detect anti-BDV antibodies. In addition, their peripheral blood mononuclear cells (PBMCs) were also examined for BDV RNA by a nested reverse transcriptase-polymerase chain reaction (RT-PCR) at ORF-II. The prevalence of BDV antibodies and/or RNA was 41.2% in Arabic, 23.5% in thoroughbred, and 33.3% in cross-bred horses, but only 17.9, 5.9, and 11.1% of them, respectively, showed positive signals for both BDV antibodies and RNA. Especially, cross-bred horses showed a higher prevalence for BDV RNA, which was detected only in females. In addition, significantly higher prevalence for BDV RNA was observed in Arabic males and thoroughbred females. The BDV prevalence did not increase with aging of the horse. Sequencing at the region of BDV derived from Iranian horses revealed a slight difference from those of Japanese horse- and European horse-derived BDVs even in the amino acid residues, although those in the three groups of Iranian horses were quite similar. Thus, the varied prevalence of BDV was observed with the horse strain or sex in Iranian horses, although BDV sequences were very similar among all three groups in Iran compared with those derived from other countries.

Amino Acid Sequence↗
PubMed1996

Serial passage of human immunodeficiency virus type 1 generates misalignment deletions in non-essential accessory genes.

Human immunodeficiency virus type 1 (HIV-1) derived from an infectious molecular clone pNL432 was extensively passaged in tissue culture by repeated rounds of acute infection. We previously showed the natural occurrence of a nonsense mutation in the vpr gene during continued passage of this virus. In this report, we show that two forms of large deletions (561 and 518 base pairs containing short direct repeats at the deletion junctions) occur after passage 50 in the region that spans the vif and vpr open reading frames. One model to explain the occurrence of these deletion regions is that such mutations result from misalignment of the growing point at a limited number of nucleotide positions. Infection of CD4+ T-cells with a recombinant HIV-1 construct containing the same vif to vpr deletion showed virtually no cytopathogenic phenotype. Thus, misalignment deletions at non-essential accessory genes of HIV-1 might be induced during replication, which result in the generation of virus with a low cytopathogenic potential.

Base Sequence↗
PubMed1996

Possible correlation between Borna disease virus infection and Japanese patients with chronic fatigue syndrome.

Borna disease virus (BDV) is a neurotropic, as yet unclassified, non-segmented, negative-sense, single-strand RNA virus. Natural infection with this virus has been reported to occur in horses and sheep. In addition, antibodies to BDV in plasma or BDV RNA in peripheral blood mononuclear cells (PBMCs) were also found in patients with neuropsychiatric diseases. We describe here the possible link between the patients with chronic fatigue syndrome (CFS) and infection with BDV.

Adult↗
PubMed1996

Unusually high seroprevalence of Borna disease virus in clade E human immunodeficiency virus type 1-infected patients with sexually transmitted diseases in Thailand.

The seroprevalence of Borna disease virus (BDV) in human immunodeficiency virus type 1-infected individuals in Thailand was examined by using recombinant BDV p24. A high (38 to 48%) rate of seroprevalence of BDV was observed in clade E-infected patients with sexually transmitted diseases, compared with those in clade E-infected prostitutes (8.3%), pregnant women (0%), clade B-infected intravenous-drug users (0%), and human immunodeficiency virus type 1-negative blood donors (1.9%).

AIDS-Related Opportunistic Infections↗
PubMed1996

Demonstration of borna disease virus RNA in peripheral blood mononuclear cells derived from domestic cats in Japan.

Borna disease virus (BDV) naturally infects horses, sheep, and several other species, including humans, and it is believed to be related to neurological disorders. BDV infection in domestic cats has also been demonstrated by serological assays. We demonstrated for the first time BDV RNA in peripheral blood mononuclear cells from 11 of 83 (13.3%) randomly selected domestic cats in Japan by nested reverse transcriptase-PCR. The BDVs from cats were similar to but slightly different from those from horses and humans, as shown by sequencing the reverse transcriptase-PCR products. None of the cats was positive for both BDV RNA and anti-BDV antibodies.

Amino Acid Sequence↗
PubMed1996

A new haemocompatible phospholipid polyurethane based on hydrogenated poly(isoprene) soft segment.

A new haemocompatible phospholipid polyurethane based on hydrogenated poly(isoprene) glycol (HPIP) and 4,4'-methylendiphenyl diisocyanate (MDI) was synthesized using 2-[bis(2-hydroxyethyl)methyl-ammonio]ethylstearylphosphate (BESP) and 1,4-butanediol (BD) as chain extender. The bulk and surface characteristics of this material was investigated by differential scanning calorimetry (DSC), dynamic viscoelasticity and tensile property measurements, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and contact angle measurement. This polymer possessed a hydrophobic surface revealed by contact angle measurement. The haemocompatibility of this polyurethane was evaluated by platelet rich plasma (PRP) contacting studies and scanning electron microscopy (SEM) observation using medical grade poly(vinyl chloride) (PVC) as the reference. The results show that this new polyurethane had relatively lower platelet adhesion and limited shape change for the attached platelets compared to PVC. The clotting time of the materials in contact with platelet poor plasma (PPP) was 99, 75, and 62 s and in contact with PRP was more than 240, 100, and 86 s for new polyurethane, PVC, and glass, respectively. This new phospholipid polyurethane is expected to have wide applications as coating or structural material for blood-contacting medical equipment due to its outstanding haemocompatibility and excellent mechanical strength.

Biocompatible Materials↗
PubMed1995

Extracellular Nef protein regulates productive HIV-1 infection from latency.

In HIV-1-infected asymptomatic carriers, the vast majority of infected cells in PBMCs are believed to be latently or nonproductively infected. We have isolated a subclone (MOLT-20-2) from an infected T cell line that expressed HIV-1 Ags at a very low level. However, viral Ag expression was markedly up-regulated by stimulation with either TNF-alpha, A23187, or PMA, indicating that the subclone might provide a suitable model of HIV-1 latency. Our previous studies have shown that the carboxyl-terminal region of the extracellular form of HIV-1 Nef played an important role in the interaction of infected cells with uninfected T cells, and could induce the cytostatic state. This suggested that Nef might contribute to intracellular signal transduction through an interaction with latently infected cells. We show in this study that stimulation of MOLT-20-2 with soluble Nef leads to HIV-1 activation from latency in a dose-dependent manner. Moreover, using a total of 14 overlapping Nef-related synthetic peptides, stimulatory activity was mapped to a discrete peptide (amino acid residues 132-147) that had the potential to activate latent HIV-1. This novel Nef function was confirmed by activation of virus production from the PBMCs of asymptomatic carriers. In addition, Nef-dependent HIV-1 activation from latency was also observed in another independently derived, latently infected cell line, U1, though not in cell line ACH-2. These results extend the significance of the Nef activity in vivo to the regulation of productive HIV-1 infection from latency, and define the regions of the protein involved.

Amino Acid Sequence↗
PubMed1995

Demonstration of human Borna disease virus RNA in human peripheral blood mononuclear cells.

BDV naturally infects horses and sheep, and causes sporadic neurological disease. Serological evidence suggests an association of BDV, or a related virus, with specific psychiatric diseases in humans. Here, by using a nested RT-PCR technique, we demonstrate that human BDV RNA is present in the PBMC of psychiatric patients. In an examination of a total of 60 patients from 5 wards of a hospital in Japan, the detection rate differed within each ward, ranging from 8% to > 50% (37% on the average). Of particular note was the finding that the human derived BDV sequences, which included deleted forms in about 23% of the positive samples, were slightly different from those derived from horse BDV. These results suggest urgent consideration of the measures to be taken to cope with the effects of blood transfusion. In addition, the detection of a high level of BDV in the PBMC of patients will help our understanding of the pathogenesis in the disease.

Antibodies, Viral↗
PubMed1995

Prevalence of Borna disease virus RNA in peripheral blood mononuclear cells from blood donors.

The presence of Borna disease virus (BDV) in peripheral blood mononuclear cells (PBMC) of 100 blood donors from Sapporo and 72 blood donors from Tokyo was examined using nested reverse transcriptase/polymerase chain reaction amplification with specific-primers for BDV p24. Anti-BDV p24 antibodies in the plasma of the 100 blood donors from Sapporo also were studied by enzyme-linked immunosorbent assay and by Western blot. BDV RNA was detected in 3 (4.2%) of the 72 PBMC samples from Tokyo, and in 5 (5%) of the 100 PBMC samples from Sapporo. In contrast, anti-p24 antibodies were found in only 1 (1%) of the donors from Sapporo. These results suggest that BDV infection in humans may be more widespread than previously thought.

Adolescent↗