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Y Kohno

Publications and source records attributed to Y Kohno.

At least 19 recordsLinked to original sources
PubMed1996

Induction of apoptosis in HL-60 human promyelocytic leukemia cells by adenosine A(3) receptor agonists.

The effects of adenosine (ADO) analogs on cells of the human promyelocytic HL-60 line were examined. ADO A(3) receptor agonists, N(6)-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide (IB-MECA, 30-60 microM) and 2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide (CI-IB-MECA, 10-30 microM) induced apoptotic cell death. In contrast, neither an A(1)/A(2) antagonist (XAC) nor other selective ADO receptor agonists (CPA, NECA and CGS21680) induced apoptosis at concentrations of <30 microM. Both IB-MECA and CI-IB-MECA significantly induced Ca(2+) release from intracellular Ca(2+) pools followed by Ca(2+) influx, suggesting the presence of phospholipase C-coupled ADO A(3) receptors on HL-60 cells. This was further supported by the presence of mRNA of ADO A3 receptor in the cells. These results suggest that activation of ADO A(3) receptors is responsible for the ADO-induced apoptosis in HL-60 cells and could be of potential therapeutic value in the treatment of leukemia.

Adenosine↗
PubMed1996

Establishment and characterization of alpha s1-casein-specific T-cell lines from patients allergic to cow's milk: unexpected higher frequency of CD8+ T-cell lines.

To study cow's milk allergy at the cellular level, we assessed the reactivity of peripheral blood mononuclear cells from patients allergic to cow's milk to alpha s1-casein, which is one of the major allergens in cow's milk. Proliferation of the cells to alpha s1-casein activation showed a rather weak response. Therefore to understand T-cell reactivity to alpha s1-casein in more detail, we prepared alpha s1-casein-specific T-cell lines from patients allergic to cow's milk and established 26 T-cell lines. These T-cell lines could be classified into three groups by analyzing their surface marker expression: those containing predominantly CD4+ CD8- T cells, those containing both CD4+CD8- and CD4-CD8+ T cells, and those containing predominantly CD4- CD8+ T cells. The CD8+ T cells were obtained at an unexpectedly higher frequency from the patients. These T-cell lines produced interferon-gamma and IL-4. These results suggest that CD8+ T cells specific for alpha s1-casein and CD4+ T cells were primed by the stimulation with alpha s1-casein in patients allergic to milk and that both T cells may play a key role in the onset, progression of, or recovery from cow's milk allergy.

CD8-Positive T-Lymphocytes↗
PubMed1996

Sequence and expression patterns of mouse SPR1: Correlation of expression with epithelial function.

A final event in the terminal differentiation of stratified squamous epithelia is the formation of a cornified cell envelope, which is a complex of several proteins cross-linked together by transglutaminases. One set of proteins is the family of small proline rich (SPR) proteins. In human foreskin epidermal cell envelopes, SPRs serve as cross-bridging proteins among the more abundant loricrin. In order to study further their evolution and expression, we have isolated and sequenced cDNAs encoding two mouse SPR1 proteins, SPR1a and SPR1b Comparative sequence analysis showed the preservation of the overall structure of mammalian SPR1 proteins with highly conserved termini and a central peptide domain repeated 13 (SPE1a) or seven (SPR1b) times. Tissues obtained from mouse fetal, newborn, and adult skin were tested by Northern blot analyses, in situ hybridization and immunohistochemistry using an antibody raised to a synthetic peptide corresponding to the C terminus of the SPR1a protein. Skin expression was first detected in fetal periderm in anagen hair follicles of newborn and older mice, and in the thickened epidermis of the lip and footpad, but no signal was detected in interfollicular trunk epidermis. High levels of SPR1a expression were found in epithelia from the forestomach and penis, and in benign squamous papillomas. Other epithelia expressing SPR1a include the tongue, esophagus, and vagina. Whenever detected, SPR1a positive staining was present in the spinous and granular layers. In the forestomach and papillomas, the periphery of cells in the cornified layer was also stained. Our results suggest that SPR1a participates widely in the construction of cell envelopes in cornifying epithelia characterized by either increased thickness or a requirement for extreme flexibility. Based on its likely function as a cross-bridging protein in cell envelopes, we conclude that the mechanical attributes of cell envelopes may be determined in part by the SPR1 content, in accordance with the specific function of the epithelium.

Animals↗
PubMed1996

Allergenic epitopes of ovalbumin (OVA) in patients with hen's egg allergy: inhibition of basophil histamine release by haptenic ovalbumin peptide.

We studied allergenic determinants that induce hypersensitivity to OVA, the major allergen in egg allergy, using immunoblot and histamine release assays. Immunoblot analysis demonstrated a part of the OVA epitope was in the C-terminal region comprising residues 347-385 (OVA347-385). Histamine was released from basophils of a patient with egg allergy upon stimulation with the OVA fragment corresponding to OVA347-385. Furthermore, detailed epitope mapping using overlapping peptides (residues 347-366, OVA-A; residues 357-376, OVA-B; and residues 367-385, OVA-C) in the OVA 347-385 region was carried out using the histamine release assay. In order for histamine release from basophils to occur, the allergen must possess two or more allergenic determinants located on the protein molecule at distances that would be equivalent to the distances between IgE molecules on the membrane surface. these results suggest that there are at least two epitopes that bind IgE antibodies on each OVA peptide. In addition, one epitope that binds IgE antibodies in two patients appears to reside in the haptenic peptide OVA357-366 (OVA-B1). The histamine release from basophils stimulated by OVA-B was completely inhibited by OVA-B1 in one of these patients. Similarly, OVA-B1 inhibited the histamine release produced by OVA-A in the other by more than 40%. These results suggest that haptenic synthetic peptides could regulate the allergic reaction in the effector phase if common epitope(s) recognized by IgE antibodies in the patients with egg allergy can be found. These are the first studies that provide an antigen-specific approach to inhibiting histamine release from basophils by a haptenic peptide recognized by IgE antibodies in an allergic disorder.

Allergens↗
PubMed1996

Establishment and characterization of ovalbumin-specific T cell lines from patients with egg allergy.

In order to investigate T cell recognition of allergens in hen egg allergy, we have established 30 ovalbumin (OVA)-specific T cell lines (TCLs) from peripheral blood mononuclear cells of 6 patients with atopic dermatitis, who are positive for IgE antibodies to OVA and clinically allergic to hen egg, and characterized them for their cytokine production pattern. All TCLs we could study were mainly composed of CD4+ T cells. Most TCLs produced significant amounts of interleukin 4 (IL-4) and IL-5 but no or very little interferon gamma on antigen stimulation, suggesting that these TCLs belong to TH2-type T cells. Restriction elements and epitope specificities were further studied on some TCLs. Antibody blocking of the proliferative responses of the TCLs to OVA indicated that HLA-DR are acting as the dominant restriction elements for these TCLs with minor contribution of HLA-DQ. By use of 187 overlapping synthetic peptides covering the whole sequence of OVA, at least 3 different T cell epitopes were identified.

Allergens↗
PubMed1995

Species differences in hydrolysis of isocarbacyclin methyl ester (TEI-9090) by blood esterases.

Species differences in the hydrolysis of isocarbacyclin methyl ester (TEI-9090) in whole blood and in its separated components were studied in rats, dogs and human. Esterase activity in rat whole blood was approximately 100 and 400 times higher than that in dog and human whole blood, respectively, and was attributed to high plasma activity. In contrast, TEI-9090 hydrolysis activities in dog and human blood were due to red blood cells (RBC), whose activity in humans was slightly suppressed by albumin. In dogs, activity in RBC membranes was 10 times greater than in the cytosol, while in human membrane and cytosol activity was virtually the same. The effects of the esterase inhibitor diisopropylfluorophosphate, bis-p-nitrophenylphosphate (BNPP), eserine, 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) and p-chloromercuribenzoate showed that the rat plasma and RBC cytosol esterases hydrolysing TEI-9090 were carboxylesterase (CarbE) and arylesterase (ArE), respectively. The esterases in dog plasma and RBC membrane were CarbE, and RBC cytosol esterase was ArE. In humans, the esterase activities in plasma, RBC membrane and cytosol were butyrylcholinesterase, CarbE and ArE, respectively.

Animals↗
PubMed1995

Kinetic study of quenching reaction of singlet oxygen and scavenging reaction of free radical by squalene in n-butanol.

The rate constant of quenching of singlet oxygen (kQ) by squalene (SQ) is found to be much larger than those of the lipids in human skin surface. SQ is the first target lipid in human skin surface by oxidative stresses such as sun light exposure. kQ of SQ is similar to that of 3,5-di-t-butyl-4-hydroxytoluene (BHT). The large kQ of SQ is due to the small ionization potential. SQ consists of six 2-methyl-2-pentene units and kQ of SQ is about 6-times as large as that of 2-methyl-2-pentene. The electron donating property of methyl groups bonded to quaternary carbons of SQ is essential to the large kQ. SQ is not very susceptible to peroxidation and is stable for attacks by peroxide radicals. The chain reaction of lipid peroxidation is unlikely to be propagated with SQ in human skin surface. It is concluded that SQ functions as an efficient quencher of singlet oxygen and prevents the corresponding part of lipid peroxidation in human skin surface.

1-Butanol↗
PubMed1995

Action of intravenously administered talipexole on the rat striatal neurons receiving excitatory input from nigral dopamine neurons.

Electrophysiological studies using rats anesthetized with chloral hydrate were performed to elucidate whether or not intravenously injected talipexole acted as a D2 receptor agonist on the striatal neurons in comparison with the action of bromocriptine. The activities of the striatal neurons were extracellularly recorded using a glass microelectrode attached along a seven-barreled micropipette, each barrel of which was filled with talipexole, bromocriptine, SCH23390 (D1 antagonist), domperidone (D2 antagonist), glutamate or 2 M NaCl. These drugs were iontophoretically applied to the immediate vicinity of the target neuron being recorded. The effects of talipexole and bromocriptine were examined on the neurons, whose spikes (induced by the stimulation of the substantia nigra pars compacta) were inhibited by the iontophoretic application of domperidone. Iontophoretic application of talipexole or bromocriptine increased spontaneous firing of these neurons and this increase in firing was also inhibited by iontophoretically applied domperidone. In the same neurons, intravenously administered talipexole (0.01, 0.02 and 0.04 mg/kg) dose-dependently increased firing, and this increase was inhibited by microiontophoretically applied domperidone, but not by SCH23390. On the other hand, the intravenous injection of bromocriptine (0.1, 0.2 and 0.4 mg/kg) also increased the firing rate. However, the increase was not dose-dependent and fluctuated; the firing transiently decreased during the increase in firing with intravenously administered bromocriptine. However, the bromocriptine-induced increase in firing was also suppressed by domperidone, and decrease in firing was inhibited by SCH23390. These findings suggest that talipexole acts as a D2 agonist on the striatal neurons receiving input from substantia nigra pars compacta and increases firing when intravenously applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Heterogeneity of neurogenic responses in intra- and extrameningeal arteries of dogs.

1. Neurogenic responses to transmural electrical stimulation were examined in endothelium-denuded extrameningeal (vertebral and carotid) and intrameningeal (spinal, basilar and middle cerebral) arteries isolated from dogs. 2. In the extrameningeal arteries, transmural electrical stimulation produced a phasic contraction. This contraction was abolished by tetrodotoxin, prazosin and guanethidine. However, alpha,beta-methylene ATP and NG-nitro-L-arginine (L-NOARG) had no significant effect on the contractile responses. 3. In the intrameningeal arteries, the neurogenic responses to electrical stimulation were composed of a transient contraction and relaxation. The transient contraction was selectively inhibited by guanethidine L-NOARG abolished the relaxation but not the contraction induced by electrical stimulation. Prazosin had no effect on either neurogenic response. 4. Noradrenaline produced a large contraction in the extrameningeal arteries which was selectively inhibited by prazosin. alpha,beta-Methylene ATP produced neither contraction nor inhibition of the response to noradrenaline in the extrameningeal arteries. 5. In the intrameningeal arteries, alpha,beta-methylene ATP produced a greater contraction than noradrenaline. The response to alpha,beta-methylene ATP was selectively abolished by desensitization of P2x-purinoceptors with alpha,beta-methylene ATP itself. The contractile response to noradrenaline was inhibited by rauwolscine but not by prazosin. 6. ATP produced endothelium-dependent relaxations in the extrameningeal and intrameningeal arteries, which were attenuated by endothelium removal. 7. NADPH diaphorase-positive fibres were dense in the middle cerebral and basilar arteries but rare or absent in the spinal artery. In the extrameningeal arteries diaphorase-positive traces were observed in the vasa vasorum. 8. The present findings indicate that the neurogenic responses of intrameningeal arteries of dogs are composed of NO-ergic and sympathetic purinergic components, while the extrameningeal arteries tested produced only sympathetic adrenergic responses, suggesting that regional heterogeneity may be associated with a sudden transition in innervation and receptor expression at the meninx.

Adenosine Triphosphate↗
PubMed1995

Inhibitory action of nebracetam on various stimuli-evoked increases in intracellular Ca2+ concentrations in cultured rat cerebellar granule cells.

Nebracetam (10-100 microM) dose-dependently inhibited increases in intracellular Ca2+ concentrations evoked by various stimuli in cultured rat cerebellar granule cells. The magnitude of the nebracetam (100 microM)-induced inhibition of L-glutamate- and N-methyl-D-aspartate-evoked Ca2+ responses was 1.5-fold and 1.7-fold greater, respectively, than the inhibition of the high K(+)-evoked response. These findings suggest that in cultured cerebellar granule cells, nebracetam attenuates the external Ca2+ influx derived from the activation of N-methyl-D-aspartate receptor-gated rather than voltage-gated Ca2+ channels.

Animals↗
PubMed1995

Histological evidence for neuroprotective action of nebracetam on ischemic neuronal injury in the hippocampus of stroke-prone spontaneously hypertensive rats.

The protective effect of nebracetam on ischemic neuronal damage was histologically examined in the pyramidal cell layer of the hippocampal CA1 subfield 7 days after operation using stroke-prone spontaneously hypertensive rats (SHRSP) subjected to 10-min bilateral carotid occlusion. Nebracetam (50 and 100 mg/kg), given orally 10 min after reperfusion, dose-dependently protected against ischemic delayed neuronal damage in the SHRSP with occlusion; however, the blood pressure remained unchanged following nebracetam administration. These findings further support the notion that nebracetam protects against ischemic delayed neuronal cell death in the hippocampus.

Animals↗
PubMed1995

[Clinical evaluation of 123I-metaiodobenzylguanidine myocardial scintigram in patients with valvular heart disease].

Myocardial sympathetic nerve function can be evaluated by 123I-metaiodobenzylguanidine (MIBG) scintigraphy. Congestive heart failure is closely related to myocardial sympathetic nerve function. This study evaluated the severity of congestive heart failure in 30 patients with valvular heart disease [aortic regurgitation (AR): n = 20, mean age = 70 +/- 13 years; mitral regurgitation (MR): n = 10, mean age = 61 +/- 18 years], who had chronic heart failure by MIBG myocardial scintigraphy. Single photon emission computed tomography (SPECT) and anterior planar myocardial images were obtained 15 minutes (initial images) and 4 hours (delayed images) after injection of MIBG (111MBq). Defect score was determined by the delayed SPECT images visually as a semi-quantitative index. Myocardial MIBG uptake was quantified by the heart to upper mediastinum uptake ratio on the delayed anterior planar images (H/M) and mean cardiac MIBG washout rate during 4 hours was calculated from the bull's eye display data (clearance). These indices were compared with the NYHA class and echocardiographic findings of the patients. MIBG regional defect in the delayed image was most frequently seen in the inferoposterior wall, and defect score and clearance were significantly higher and the H/M ratio was significantly lower in NYHA class III patients than in class II patients. In patients with AR, clearance significantly correlated with left ventricular end-systolic dimension. In patients with MR, both the H/M ratio and clearance significantly correlated with left atrial dimension. Defect score, H/M, and clearance were closely related to the severity of AR and MR. These results indicate that MIBG scan can be used to assess the severity of valvular heart disease.

3-Iodobenzylguanidine↗
PubMed1995

[Nasal smear cytology in bronchial asthma: correlation of appearance and numbers of nasal smear mast cells, eosinophils or basophils and serum IgE antibodies to house dust mite in patients with bronchial asthma].

Nasal smear cytology was studied in pediatric patients with bronchial asthma with special reference with IgE RAST to house dust mite, Dermatophagoides pteronyssinus (Dp). Results obtained were as follows: (1) Numbers of eosinophils on the nasal smear correlated well with Dp RAST score, (2) mast cells were detected before Dp RAST becoming positive and appearance of eosinophils, (3) basophils appeared after detection of eosinophils and only in patients with nasal smear eosinophils. These results suggest that mast cells are the early marker for allergic inflammation and basophils and eosinophils appear in association with overt sensitization with house dust mite in house dust mite-sensitized asthmatic patients.

Adolescent↗
PubMed1994

Chondroitinase ABC-resistant sulfated trisaccharides isolated from digests of chondroitin/dermatan sulfate chains.

Four kinds of sulfated trisaccharides resistant to chondroitinase ABC were isolated after chondroitinase B or ABC treatment of dermatan sulfate or various chondroitin sulfate isomers, respectively. Their composition was determined by chemical analysis and fast atom bombardment-mass spectrometry. Their structures were characterized by chondroitinase ACII digestion in conjunction with HPLC, and 500-MHz one- and two-dimensional 1H NMR spectroscopy. All the four trisaccharides have in common the core saccharide sequence, alpha-L-delta 4,5HexpA-(1-->3)-beta-D-GalpNAc-(1-->4)-D-GlcpA. A monosulfated component isolated from shark scapular cartilage chondroitin sulfate C or bovine aorta dermatan sulfate was elucidated as alpha-L-delta 4,5HexpA-(1-->3)-beta-D-GalpNAc6SO3(-)-(1-->4)-D-GlcpA or alpha-L-delta 4,5HexpA-(1-->3)-beta-D-GalpNAc4SO3(-)-(1-->4)-D-GlcpA , respectively. A disulfated component obtained from shark scapular cartilage chondroitin sulfate C or squid cartilage chondroitin sulfate E was identified as alpha-L-delta 4,5HexpA2SO3(-)-(1-->3)-beta-D-GalpNAc6SO3(-)-(1-->4)-D-G lcpA or alpha-L-delta 4,5HexpA-(1-->3)-beta-D-GalpNAc4SO3(-)6SO3(-)-(1-->4)- D-GlcpA, respectively. These trisaccharides are derived from the reducing termini of the parent polysaccharides. Some of the trisaccharides could be derived from the reducing termini exposed by the peeling reaction during the alkaline treatment while some others may represent the cleavage sites exposed by tissue endo-beta-D-glucuronidase(s), indicating the presence of such enzyme(s) which may release chondroitin/dermatan sulfate fragments from proteoglycans.

Animals↗
PubMed1994

Excitation by talipexole, a dopamine D2 agonist, of caudate nucleus neurons activated by nigral stimulation.

An electrophysiological study using cats anesthetized with alpha-chloralose was performed to elucidate whether or not talipexole (B-HT 920 CL2: 6-allyl-2-amino -5, 6, 7, 8-tetrahydro-4H-thiazolo [4, 5 -d] -azepine-dihydrochroride), a dopamine D2 agonist, acts on postsynaptic dopamine receptors in the caudate nucleus (CN) neurons receiving excitatory input from the pars compacta of substantia nigra (SN). Extracellular neuron activities were recorded in the CN using a glass-insulated silver wire microelectrode attached along a seven-barreled micropipette, each of which was filled with talipexole, quinpirole (dopamine D2 agonist), domperidone (dopamine D2 antagonist), glutamate and 2M NaCl. These drugs were microiontophoretically applied to the immediate vicinity of the target neuron. In the same neurons in which the spikes elicited by the SN stimulation were blocked by microiontophoretically applied domperidone, microiontophoretic application of talipexole and quinpirole induced a dose-dependent increase in spontaneous firing. This increase in firing by talipexole and quinpirole was blocked during simultaneous application of domperidone, although glutamate-induced firing remained unaffected by domperidone. In the CN neurons, in which the SN stimulation-induced spikes were not blocked by domperidone, spontaneous firing was not affected by talipexole or quinpirole. These findings suggest that talipexole activates CN neurons receiving a dopaminergic input from SN via D2 receptors, as does quinpirole.

Action Potentials↗
PubMed1994

Entrapping efficiency and drug release profile of an oil-in-water (o/w) emulsion formulation using a polydimethylsiloxane-coated glass bead assay.

Evaluation of entrapping efficiency is difficult for an o/w emulsion formulation containing a lipophilic oily drug, isocarbacyclin methyl ester (TEI-9090), by commonly employed techniques (dialysis, ultrafiltration, or gel filtration), because of its adsorption to the system materials. Employing this characteristic of TEI-9090, we developed an adsorption technique with polydimethylsiloxane-coated glass beads (PDMS-GB). The assay is based on the quantitative adsorption of unentrapped TEI-9090 to the PDMS-GB. The entrapping efficiency of a 10% soybean oil emulsion containing [3H]TEI-9090 (1 microgram/mL) assayed by this method approached 100%. The PDMS-GB assay was performed for the emulsion diluted 100 times with physiological saline at different time intervals after dilution over a period of 24 hr. A plot of [3H]TEI-9090 in the emulsion particles versus time showed rapid release within 1 hr, followed by very slow release, reaching equilibrium. Applying first-order kinetics, the data were found to fit to a biexponential equation over the first hour of release. The terminal release resembled the first-order release of the drug from the phospholipid-rich infranatant, which was separated from the creamy layer by ultracentrifugation of the emulsion and contained 35% [3H]TEI-9090. These results suggest that the drug is released from two components in the emulsion.

Chemical Phenomena↗