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Biomedical subjects

T Nishimura

Publications and source records attributed to T Nishimura.

At least 613 records · Page 34Linked to original sources

Induction of T cell tolerance by pretreatment with anti-ICAM-1 and anti-lymphocyte function-associated antigen-1 antibodies prevents antigen-induced eosinophil recruitment into the mouse airways.

To determine whether the induction of Th2 cell tolerance down-regulates Ag-induced eosinophil recruitment into the tissue, we studied the effect of the in vivo pretreatment with anti-ICAM-1 mAb, anti-LFA-1 mAb, and a soluble Ag on Ag-induced eosinophil infiltration in the trachea of sensitized mice. The in vivo pretreatment with anti-ICAM-1 mAb, anti-LFA-1 mAb, and a soluble Ag inhibited Ag-induced eosinophil infiltration in the mouse trachea in an Ag-specific manner. The pretreatment with anti-LFA-1 mAb and the Ag also had a weak inhibitory effect on the Ag-induced eosinophil infiltration. In contrast, the pretreatment with Ag alone, the combination of anti-ICAM-1 mAb and anti-LFA-1 mAb alone, or the combination of anti-ICAM-1 mAb and the Ag had no significant effect. In addition, the pretreatment with the two mAb and the Ag and, to a lesser degree, the pretreatment with anti-LFA-1 mAb and the Ag also prevented Ag-specific IgE production in mice. In vitro Ag-induced IL-2, IL-4, and IL-5 production was decreased in spleen cells of the mice pretreated with anti-ICAM-1 mAb, anti-LFA-1 mAb, and the Ag, but not with Ag alone or with the combination of anti-ICAM-1 mAb and anti-LFA-1 mAb alone, indicating the induction of both Th1 and Th2 cell tolerance in vivo. These results indicate that the induction of Th2 cell tolerance prevents Ag-induced eosinophil recruitment into the tissue and IgE Ab production and that ICAM-1/LFA-1 interaction is involved as a costimulatory signal in inducing T cell tolerance to a soluble Ag.

Animals↗

Tricyclic quinoxalinediones: 5,6-dihydro-1H-pyrrolo[1,2,3-de] quinoxaline-2,3-diones and 6,7-dihydro-1H,5H-pyrido[1,2,3-de] quinoxaline-2,3-diones as potent antagonists for the glycine binding site of the NMDA receptor.

A series of tricyclic quinoxalinediones, 5,6-dihydro-1H-pyrrolo[1,2,3-de]quinoxaline-2,3-diones and 6,7-dihydro-1H,5H-pyrido[1,2,3-de]quinoxaline-2,3-diones, were synthesized and was evaluated for their affinity for the glycine binding site of the NMDA receptor using a [3H]-5,7-dichlorokynurenic acid binding assay. The six-membered ring-fused tricyclic quinoxalinedione 18g (Ki = 9.9 nM) displayed high affinity for the glycine site. The anilide derivative 20g (Ki = 2.6 nM) was 4-fold more potent than 18g and as potent as L-689,560, one of the most potent glycine antagonists so far prepared. Although the carboxylic acid derivative of the corresponding five-membered ring-fused tricyclic quinoxalinedione 18e (Ki = 7.3 nM) had affinity comparable to that of 18g, the anilide derivative 20e largely decreased in the affinity in contrast to 20g. Enantiomers 23g, 24g, 25g, and 26g were prepared and tested. Only the S enantiomer 25g (Ki = 0.96 nM) retained the affinity among the anilide derivatives, whereas both enantiomers 23g (Ki = 2.3 nM) and 24g (Ki = 9.6 nM) were active among the carboxylic acid derivatives. The origin of the high affinity of carboxylic acid derivatives such as 18e and 18g would be a charge-charge interaction between the anionic carboxylate residues of the compounds and the cationic proton-donor site in the receptor.

Animals↗

Involvement of clathrin light chains in the pathology of Pick's disease; implication for impairment of axonal transport.

Clathrin, which constitutes coated vesicles and plays important roles in neuronal functions, has been reported to be involved in the pathology of Alzheimer's disease. In the brains of the patients with Pick's disease, distribution of clathrin was immunohistochemically investigated using monoclonal antibodies binding to different epitopes of clathrin light chain a and b. All the antibodies intensely labeled Pick's body and some perikarya of neurons, indicating impairment of slow axonal transport b (SCb). Antibodies against neurofilament, kinesin and synaptophysin also labeled Pick's body. These observations suggested impairment of axonal transport in the brains with Pick's disease, and might contribute to elucidating the pathology of Pick's body forming. It is implied that common pathological processes might lie in Alzheimer's disease and Pick's disease.

Antibodies, Monoclonal↗

Accumulation of amyloid beta-protein precursor (APP) in Purkinje cells and increase of amino-terminal fragments of APP in cerebrum and cerebellum of aged rat brain.

In aged rat brain, amyloid beta-protein precursor (APP) is accumulated in dendrites and cell bodies of Purkinje cells as full-length or truncated APP, because dendrites and cell bodies are positively stained by antibodies against both the amino- and carboxy-termini of APP. Western blot analysis of homogenates of brains of aged and young rats showed no apparent differences except for an increase in amino-terminal fragments in cerebrum and cerebellum of aged rat. These results indicate that the expression, transport or metabolism of APP in specific regions of brains may be affected by the aging process.

Aging↗

Role of vascular cell adhesion molecule 1/very late activation antigen 4 and intercellular adhesion molecule 1/lymphocyte function-associated antigen 1 interactions in antigen-induced eosinophil and T cell recruitment into the tissue.

To determine the role of vascular cell adhesion molecule 1 (VCAM-1)/very late activation antigen 4 (VLA-4) and intercellular adhesion molecule 1 (ICAM-1)/lymphocyte function-associated antigen 1 (LFA-1) interactions in causing antigen-induced eosinophil and T cell recruitment into the tissue, we studied the effect of the in vivo blocking of VCAM-1, ICAM-1, VLA-4, and LFA-1 by pretreatment with monoclonal antibodies (mAb) to these four adhesion molecules on the eosinophil and T cell infiltration of the trachea induced by antigen inhalation in mice. The in vivo blocking of VCAM-1 and VLA-4, but not of ICAM-1 and LFA-1, prevented antigen-induced eosinophil infiltration into the mouse trachea. On the contrary, the in vivo blocking of VCAM-1 and VLA-4, but not of ICAM-1 and LFA-1, increased blood eosinophil counts after antigen challenge, but did not affect blood eosinophil counts without antigen challenge in sensitized mice. Furthermore, the expression of VCAM-1 but not ICAM-1 was strongly induced on the endothelium of the trachea after antigen challenge. In addition, pretreatment with anti-IL-4 mAb decreased the antigen-induced VCAM-1 expression only by 27% and had no significant effect on antigen-induced eosinophil infiltration into the trachea. The in vivo blocking of VCAM-1 and VLA-4 inhibited antigen-induced CD4+ and CD8+ T cell infiltration into the trachea more potently than that of ICAM-1 and LFA-1. In contrast, regardless of antigen challenge, the in vivo blocking of LFA-1, but not of ICAM-1, increased blood lymphocyte counts more than that of VCAM-1 and VLA-4. These results indicate that VCAM-1/VLA-4 interaction plays a predominant role in controlling antigen-induced eosinophil and T cell recruitment into the tissue and that the induction of VCAM-1 expression on the endothelium at the site of allergic inflammation regulates this eosinophil and T cell recruitment.

Administration, Inhalation↗

Expression of the receptor for macrophage colony stimulating factor by brain microglia and its upregulation in brains of patients with Alzheimer's disease and amyotrophic lateral sclerosis.

The receptor for macrophage colony stimulating factor (CSF-1) was localized immunohistochemically in postmortem human brain tissue. Microglia constitutively expressed the receptor for CSF-1 and its expression was upregulated in lesions of Alzheimer's disease and amyotrophic lateral sclerosis. The CSF-1 mediated pathway appears to be involved in the response and activation of microglia in the central nervous system lesions.

Aged↗

High-level production of human blood coagulation factors VII and XI using a new mammalian expression vector.

Recombinant human proteins are generally recovered in low yields from mammalian tissue culture following transfection with commercially available vectors. We have constructed a novel vector containing both the neomycin-resistance-encoding gene (neo) as a dominant selectable marker, and the dihydrofolate reductase-encoding gene (DHFR) to enable amplification of transfected DNA followed by stable expression in mammalian cell lines. Levels of 5 micrograms/ml of the coagulation proteins, factor VII (FVII) and factor XI (FXI), have been achieved in serum-free media. N-terminal sequencing of the purified proteins, and of their separated chains after proteolytic activation, demonstrated correct processing of the recombinant products. In addition, the ratios of clotting activity to antigen for each are close to unity, and the recombinant and plasma-derived proteins had identical mobilities upon electrophoresis in the presence of SDS. The vector described will be of use for the synthesis of recombinant proteins, both wild-type and variants produced by site-directed mutagenesis, especially where complex post-translational modification of the protein makes it essential to use mammalian cells.

Animals↗

Elevated expression of messenger RNA for peripheral myelin protein 22 in biopsied peripheral nerves of patients with Charcot-Marie-Tooth disease type 1A.

The human peripheral myelin protein 22 (PMP-22) gene has been mapped to chromosome 17p11.2 in the duplicated region associated with Charcot-Marie-Tooth disease type 1A. Southern blot analysis using PMP-22 as a probe indicated that the PMP-22 gene was duplicated in 5 patients from unrelated Japanese families with Charcot-Marie-Tooth disease type 1. In order to investigate whether or not an extra copy of PMP-22 has an effect on its gene expression, we analyzed relative expression of messenger RNA for PMP-22 and protein 0 (P0) against beta-actin by Northern blotting in biopsied nerves of the patients with type 1A disease, and compared the results with those of patients having other demyelinating neuropathies and the autopsied nerves of patients without neuropathies. The relative expression of PMP-22 messenger RNA in 5 patients with Charcot-Marie-Tooth disease type 1A was significantly higher than that in 5 patients with other demyelinating neuropathies (p < 0.05). There was no statistically significant difference in P0 expression between them. This study provided direct evidence for elevated expression of PMP-22 in peripheral nerves of patients with Charcot-Marie-Tooth disease type 1A as the result of a gene dosage effect. However, the relation between elevated expression of PMP-22 and the mechanism causing demyelination remains undetermined.

Adult↗

Pro-T cells in fetal thymus express c-kit and RAG-2 but do not rearrange the gene encoding the T cell receptor beta chain.

Ten percent of 15-day fetal thymocytes of mice were Pgp-1+Thy-1lo cells. Half were strongly stained with monoclonal antibodies (mAb) recognizing the oncogene product, c-kit, but were not stained with mAb against non-T cell markers such as B220, Mac-1 and Gr-1. The isolated Pgp-1+c-kit+ thymocytes showed no rearranged bands for V-DJ and D-J of T cell receptor (TcR) beta, but Pgp-1(-)-c-kit- thymocytes showed D-J rearranged bands. Both cells expressed the RAG-2 gene which is required for the V(D)J recombination process. When Pgp-1+c-kit+ thymocytes were cultured in 2-deoxyguanosine-treated alymphocytic fetal thymus, they became TcR-expressing mature type T cells, but this differentiation was reduced by the addition of anti c-kit mAb. These data indicate that Pgp-1+c-kit+ thymocytes are pro-T cells with the potential to differentiate mature T cells in the thymic environment. This study also indicates that c-kit-mediated signals promote the differentiation of thymocytes during their early stages.

Animals↗

Role of Coulomb energy in promoting collisionally activated dissociation of multiply charged peptides formed by electrospray ionization.

Electrospray ionization tandem quadrupole mass spectrometry has been applied to a series of lysine-substituted octaalanines and some naturally occurring peptides containing more than two basic amino acid residues. Unusually high fragmentation efficiency along with site-specific cleavages at the outer side of and remote from basic residues were observed for collisionally activated dissociation spectra of multiply charged peptides (MCP) with basic residues in close proximity. It was suggested that Coulomb energy (CE) rather than Coulomb repulsion (CR) was responsible for promoting fragmentation of the MCP studied. A possible fragmentation mechanism of MCP is proposed, in which the conversion of CE into internal vibrational energy was brought about by intramolecular proton migration in the presence of CR between charged sites.

Amino Acid Sequence↗

CD11/CD18 and ICAM-1 expression in a murine foreign body granulomatous lung model.

The expression of leukocyte adhesion molecules (Leu-CAM; CD11/CD18 family) and ICAM-1 was studied on bronchoalveolar lavage (BAL) cells and lung tissue sections from a mouse lung granulomatous model. When foreign body lung granuloma were induced in mice by intratracheal injection of 1.5 x 10(4) Sephadex G-50 beads, total and differential BAL cell counts demonstrated a maximal recovery of macrophages and neutrophils at 3 days. Indirect immunoperoxidase staining patterns indicated that intratracheal challenge with beads activated BAL cells and upregulated expression of CD11b, ICAM-1, and CD18 antigenic markers on macrophages and neutrophils when compared with BAL cells from saline controls. Immunohistochemical staining also confirmed the presence of CD11b on activated macrophages and neutrophils around the beads and of the ICAM-1 antigen in the lung parenchyma of bead challenged mice.

Animals↗

An ischemic opening of the blood-brain barrier may deteriorate brain stem auditory evoked potentials following transient hindbrain ischemia in gerbils.

To clarify the effect of vasogenic brain edema on the brainstem, the relationships between waveform changes in brainstem auditory evoked potentials (BAEP) and blood-brain barrier (BBB) disturbance following transient hindbrain ischemia were investigated. Hindbrain ischemia was induced in gerbils by bilateral occlusion of the vertebral arteries. The animals were divided into three groups subjected to 0, 5, and 30 min of bilateral vertebral occlusion (BVO-0',-5', and -30' groups; n = 4 in each group). Two hours after recirculation, Evans blue (EB) solution was injected into the saphenous vein. The brains were removed after 30 min of circulation, and all areas stained macroscopically by EB were noted and recorded. During hindbrain ischemia, BAEP disappeared within 3 min. In the BVO-5' group, BAEP reappeared and returned to normal within 10 min after reperfusion, whereas in the BVO-30' group, BAEP never returned to normal and finally disappeared within 30 min after reperfusion. In the BVO-5' group, no EB staining was visible. On the other hand, in the BVO-30' group, EB staining was seen in the medial part of the tegmentum in the midbrain in two animals, and around the vestibular nucleus in the lateral parts of the pons in three. These results demonstrate the close relationship between the reversibility of ischemia-induced changes in BAEP and BBB disturbance in the brainstem.

Animals↗

Detection of coronary artery disease by dynamic planar and single photon emission tomographic imaging with technetium-99m teboroxime.

To test the clinical significance of technetium-99m teboroxime regional myocardial clearance in the detection of coronary artery disease, 25 patients underwent dynamic planar or single-photon emission tomographic (SPET) myocardial imaging with 99mTc-teboroxime after exercise and again 2 h later at rest. All patients underwent both thallium-201 exercise and redistribution SPET and coronary arteriography. The early phases of exercise 99mTc-teboroxime myocardial clearance determined by dynamic planar imaging showed a significant difference between normal and post-stenotic myocardial regions (clearance rate constant k: 0.047 +/- 0.005 min-1 versus 0.034 +/- 0.003 min-1, P < 0.001). Reflecting this "differential clearance" between myocardial regions, an early redistribution-like phenomenon was observed in a significant number of myocardial segments by comparing serially acquired post-exercise 99mTc-teboroxime SPET images. These results indicated that the analysis of 99mTc-teboroxime myocardial clearance was of potential use in the detection of coronary artery disease, yielding additional information to that provided by the tracer distribution analysis. Although the early redistribution-like phenomenon of 99mTc-teboroxime could be the source of underestimation of ischaemia if acquisition of the initial post-exercise image were delayed, it could also prove useful in the early differentiation of ischaemia from scar because when the phenomenon was observed in delayed post-exercise images, the rest study could be omitted under some circumstances.

Coronary Angiography↗

Involvement of clathrin light chains in the pathology of Alzheimer's disease.

Clathrin, which constitutes coated vesicles, plays important roles in neuronal functions. In the brains of the patients with Alzheimer's disease, distribution of clathrin was immunohistochemically investigated using four monoclonal antibodies against clathrin light chains, LCB.1, LCB.2, X-16 and CON.1, to study the involvement of clathrin in the pathology of Alzheimer's disease. LCB.1, LCB.2, X-16, and CON.1 bind to the aminoterminus of the clathrin light chain b(LCb), to the neuron-specific insert of LCb, to the light chain a(LCa), and to LCa and LCb, respectively. In Alzheimer brains, granular staining of LCB.2 around neurons in the hippocampus was weaker or patchily defected in comparison with control brains. Some neurofibrillary tangles and neurons were intensely stained in Alzheimer brains by LCB.2, whereas neurons were weakly stained in control brains. Crowns of some senile plaques in the brains of early onset Alzheimer's disease were positively stained by LCB.2. LCB.1 supported the observations of LCB.2. Reactive astrocytes in Alzheimer brains were intensely stained by X-16. On the other hand, Western blot analysis using LCB.2 and X-16 demonstrated no apparent differences in protein amounts and molecular weights of LCa and LCb between control and Alzheimer brains. These observations demonstrated abnormal distribution of clathrin in Alzheimer brains, implying impairment of axonal transport in this disease.

Adult↗

MRI-based quantitative assessment of the hippocampal region in very mild to moderate Alzheimer's disease.

We investigated the hippocampal region in six patients diagnosed with possible Alzheimer's disease (AD), eight patients with probable AD, and eight age-matched controls, using a high-resolution magnetic resonance imaging technique. Coronal T1-weighted images were used for area measurements of the hippocampal formation (HF), parahippocampal gyrus (PHG), and temporal lobe (TL), normalised to cranial area. Both the normalised HF and PHG were significantly smaller in both AD groups than in the controls, but did not differ between patients with possible and probable AD. The normalised TL was significantly smaller in patients with probable AD than in those with possible AD and controls, but did not differ in patients with possible AD and controls. We conclude that hippocampal and parahippocampal atrophy occurs in early AD, and is more useful than neocortical atrophy for early detection of the disease. At a more advanced stage, the neocortical area is involved.

Aged↗

The granulocyte colony-stimulating factor produced in the human lung and its effect on liquid movement in the rabbit lung.

Levels of the granulocyte colony-stimulating factor (G-CSF) were determined in the plasma and resected lung tissue from patients who underwent pulmonary resection. Moreover, the effect of recombinant human (rh) G-CSF on the permeability of pulmonary endothelium and on liquid clearance from the alveolar spaces was investigated in rabbits. The plasma levels of G-CSF increased from 30 pg/ml preoperatively to 409 +/- 236 pg/ml 3 h postoperatively (P < 0.05), while the levels of G-CSF in the resected lung tissue were increased in the alveolar fluid, to 1,834 +/- 1,054 pg/ml, and in the pulmonary blood, to 5,466 +/- 2,019 pg/ml. It was found that rh G-CSF 25 micrograms administered into the subcutaneous tissue of rabbits increased extravascular lung water to 3.45 +/- 0.26 vs 2.98 +/- 0.20 in control experiments (P < 0.05); however, rhG-CSF 0.75 microgram/kg administered into the alveolar spaces did not affect liquid clearance from the alveolar spaces. The findings of this study led us to conclude that G-CSF is synthesized in the human lung and increases the permeability of pulmonary endothelium, but not liquid clearance across the alveolar epithelium.

Animals↗

A new gerbil model of hindbrain ischemia by extracranial occlusion of the bilateral vertebral arteries.

A new gerbil model of hindbrain ischemia was induced by extracranial occlusion of the bilateral vertebral arteries just before their entry into the transverse foramen of the cervical vertebra. Carbon black studies, performed at 5 min after occlusion, revealed that the pons-medulla oblongata, and the cerebellum were quite ischemic in all animals. Cardiovascular changes in mean arterial blood pressure (MABP) and heart rate were recorded until 30 min after occlusion, and revealed that the typical cerebral ischemic response (i.e., abrupt increase in MABP, bradycardia, and apnea) was elicited in all animals (n = 10). Thirty minutes after occlusion, animals (n = 4) were decapitated and immersion-fixed. Brain sections were stained with hematoxylin-eosin (HE) and also immunostained for microtubule-associated protein 2 in order to evaluate ischemic neuronal damage from 30 min of ischemia. By HE staining, ischemic lesions were detected bilaterally in the oculomotor, the trigeminal motor, the lateral vestibular, and the cerebellar interpositus nucleus. In addition, immunostaining revealed ischemic lesions in several other hindbrain areas. In conclusion, we could successfully establish a new gerbil model of hindbrain ischemia. Carbon black perfusion and hemodynamic studies revealed that severe and reproducible hindbrain ischemia was produced. By histopathological examination, we could also clearly demonstrate symmetrical ischemic lesions in several hindbrain areas.

Animals↗