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Biomedical subjects

Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 91 records · Page 5Linked to original sources
PubMed2001

Identification of beta-lactoglobulin-derived peptides and class II HLA molecules recognized by T cells from patients with milk allergy.

BACKGROUND: Cow's milk allergy impairs the health and development of many infants since it deprives them of adequate nutrition. Cow's milk fractions contain many allergens, and beta-lactoglobulin (BLG) is one of the major allergens. OBJECTIVE: The purpose of this study was to determine T cell epitopes, antigen-presenting molecules and cytokine production by T cells in relation to BLG. The results can provide new therapeutic possibilities of using analogue peptides of BLG for infants with cow's milk allergy. METHODS: Using a mixture of a panel of overlapping synthetic peptides that cover the entire BLG molecule, we established polyclonal BLG-specific short-term T cell lines and clones from peripheral blood mononuclear cells of four patients with allergy to cow's milk carrying most of the common human leucocyte antigen (HLA) haplotypes seen in the Japanese population. We then identified the T cell epitopes and antigen-presenting molecules, and measured the production of cytokines interleukin (IL)-4, IL-5 and interferon-gamma in the culture supernatants. RESULTS: The T cell lines established from the four patients responded to seven different peptides. Three of the peptides stimulated the T cells of two donors, regardless of the HLA types. The patterns of inhibition of the proliferative responses of the cell lines by anti-HLA class II antibodies were heterogeneous; three were mainly inhibited by anti-HLA-DR mAbs, and the other was inhibited by anti-HLA-DQ mAbs. High levels of IL-5 were produced by these T cell lines. CONCLUSIONS: Patients' T cells recognized BLG in association with a variety of HLA-DR or -DQ as antigen-presenting molecules. Although some peptides did have a more potent T cell stimulatory activity than others, the T cell receptor ligands formed with the BLG molecule are heterogeneous. Peptides for the desensitization of T cells of the patients with cow's milk allergy need to be designed keeping in mind the different requirements in different ethnic groups.

Amino Acid Sequence↗
PubMed2001

Yeast Saccharomyces cerevisiae has two cis-prenyltransferases with different properties and localizations. Implication for their distinct physiological roles in dolichol synthesis.

BACKGROUND: Dolichol is a family of long-chain polyprenols, which is utilized as a sugar carrier in protein glycosylation in the endoplasmic reticulum (ER). We have identified a key enzyme of the dolichol synthesis, cis-prenyltransferase, as Rer2p from Saccharomyces cerevisiae. We have also isolated a multicopy suppressor of an rer2 mutant and named it SRT1. It encodes a protein similar to Rer2p but its function has not been established. RESULTS: The cis-prenyltransferase activity of Srt1p has been proved biochemically in the lysate of yeast cells lacking Rer2p. The polyprenol product of Srt1p is longer in chain length than that of Rer2p and is not sufficiently converted to dolichol and dolichyl phosphate, unlike that of Rer2p. The subcellular localization of these two isozymes has been examined by immunofluorescence microscopy and by the use of GFP fusion proteins. Whereas GFP-Rer2p is localized to the continuous ER and some dots associated with the ER, GFP-Srt1p shows only punctate localization patterns. Immunofluorescence double staining with Erg6p, a marker of lipid particles in yeast, indicates that Srt1p is mainly localized to lipid particles (lipid bodies). RER2 is mainly expressed in the early logarithmic phase, while the expression of SRT1 is induced in the stationary phase. CONCLUSIONS: We have shown that yeast has two active cis-prenyltransferases with different properties. This result implies that the two isozymes have different physiological roles during the life cycle of the yeast.

Dimethylallyltranstransferase↗
PubMed2001

Differentiation of Herpes simplex virus types 1 and 2 in sera of patients with HSV central nervous system infections by type-specific enzyme-linked immunosorbent assay.

OBJECTIVE: To differentiate by enzyme-linked immunosorbent assay (ELISA) using type-specific glycoprotein G herpes simplex virus (HSV) type 1 and type 2 in serum collected from patients with HSV central nervous system (CNS)infections. METHODS: HSV 1 and 2 typing in convalescent sera of 17 patients with HSV acute encephalitis, myelitis, or meningitis was determined by the type-specific IgG ELISA kit (Gull Laboratory, Inc.). HSV CNS infections were diagnosed by polymerase chain reaction (PCR) or conventional serologic tests from acute to convalescent stages. RESULTS: In 13 of 17 patients, HSV type 1 and HSV type 2 antibodies were positive; 11 patients with HSV type 1 and 2 patients with HSV type 2 were found. All 10 patients with encephalitis showed equivocal or positive results for HSVtype 1. In two of three cases of myelitis, HSV type 1 was demonstrated. Each case of myelitis and meningitis reacted to both types 1 and 2. CONCLUSION: These data suggest that the kit is useful for type differentiation of HSV CNS infections from convalescent sera, and can play a supplementary role in HSV typing by PCR or previous serologic tests.

Adult↗
PubMed2001

Sciatic nerve regeneration through alginate with tubulation or nontubulation repair in cat.

A novel material for nerve regeneration, alginate, was employed in both tubulation and nontubulation repair of a long peripheral nerve defect injury. Twelve cats underwent severing of the right sciatic nerve to generate a 50-mm gap, which was treated by tubulation repair (n = 6) or nontubulation repair (n = 6). In the tubulation group, a nerve conduit consisting of polyglycolic acid mesh tube filled with alginate sponge was implanted into the gap and the tube was sutured to both nerve stumps. In the nontubulation group, the nerve defect was repaired by a simple interpolation of two pieces of alginate sponge without any suture. The animals in both groups exhibited similar recovery of locomotor function. Three months postoperatively, successful axonal elongation and reinnervation in both the afferent and efferent systems were detected by electrophysiological examinations. Intracellular electrical activity was also recorded, which is directly indicative of continuity of the regenerated nerve and restoration of the spinal reflex circuit. Eight months after operation, many regenerated myelinated axons with fascicular organization by perineurial cells were observed within the gap, peroneal and tibial branches were found in both groups, while no alginate residue was found within the regenerated nerves. In morphometric analysis of the axon density and diameter, there were no significant differences between the two groups. These results suggest that alginate is a potent material for promoting peripheral nerve regeneration. It can also be concluded that the nontubulation method is a possible repair approach for peripheral nerve defect injury.

Alginates↗
PubMed2001

Structure of the DNA-binding domain of human telomeric protein, TRF1 and its interaction with telomeric DNA.

TRF1, a key player in regulation of the telomere length, is a double-stranded telomeric DNA binding factor in vertebrate. The DNA-binding domain of TRF1 shows a sequence similarity to each of the tandem repeat in the DNA-binding domain of the c-Myb protein. Here, the solution structure of the DNA-binding domain of human TRF1 has been determined by NMR. It consists of three helices, and its topological arrangement is very close to that of each c-Myb repeat and also to that of each subdomain of the DNA-binding domain in yeast telomeric protein, Rap1p. The interaction with DNA has been investigated by chemical shift perturbations. The result suggests that TRF1 recognizes the sequence centered on AGGGTTA mainly with its N-terminal arm, N-terminal portion of second helix and both ends of third helix.

Base Sequence↗
PubMed2001

The chloroplast clpP gene, encoding a proteolytic subunit of ATP-dependent protease, is indispensable for chloroplast development in tobacco.

ClpP is a proteolytic subunit of the ATP-dependent Clp protease, which is found in chloroplasts in higher plants. Proteolytic subunits are encoded both by the chloroplast gene, clpP, and a nuclear multi gene family. We insertionally disrupted clpP by chloroplast transformation in tobacco. However, complete segregation was impossible, indicating that the chloroplast-encoded clpP gene has an indispensable function for cell survival. In the heteroplasmic clpP disruptant, the leaf surface was rough by clumping, and the lateral leaf expansion was irregularly arrested, which led to an asymmetric, slender leaf shape. Chloroplasts consisted of two populations: chloroplasts that were similar to the wild type, and small chloroplasts that emitted high chl fluorescence. Ultrastructural analysis of chloroplast development suggested that clpP disruption also induced swelling of the thylakoid lumen in the meristem plastids and inhibition of etioplast development in the dark. In mature leaves, thylakoid membranes of the smaller chloroplast population consisted exclusively of large stacks of tightly appressed membranes. These results indicate that chloroplast-encoded ClpP is involved in multiple processes of chloroplast development, including a housekeeping function that is indispensable for cell survival.

Adenosine Triphosphatases↗
PubMed2001

Concurrent chemoradiotherapy for oropharyngeal carcinoma.

The clinical results of definitive chemoradiotherapy for oropharyngeal carcinoma were retrospectively analyzed. Thirty-one patients with oropharyngeal carcinoma who received definitive radiation therapy between January 1986 and June 1998 were analyzed. The median age was 61 years. All patients had squamous cell carcinoma. According to the Union International Contre le Cancer 1997 classification system, stage I, II, III, IVA, and IVB were 1,0, 9, 14, and 7, respectively. Regarding the primary site, 23 tumors were in the lateral wall, whereas 2 were in the superior wall, and 3 each were in the anterior and posterior walls. The median total dose was 66 Gy, with a range of 60 Gy to 74.4 Gy. The overall treatment time ranged from 39 days to 113 days, with a median of 50 days. Seven patients underwent hemilateral radical neck dissection. Fourteen patients received concurrent chemotherapy using weekly cisplatin (50 mg/d) at least three times. The 5-year overall and cause-specific survival (CSS) rates were 55% and 62%, respectively. All local recurrences occurred within 2 years. The CSS rate in patients with lateral or superior wall origin was significantly superior to that of patients with anterior or posterior wall origin (p < 0.05). The 3-year CSS rate was 83% for patients treated with concurrent chemoradiotherapy using weekly cisplatin at least 3 times, whereas that was 53% for the remaining patients (p < 0.05). No serious adverse effects were observed. It is concluded that definitive concurrent chemoradiotherapy using weekly cisplatin for oropharyngeal carcinoma appear promising.

Adult↗
PubMed2001

In vivo cultured skin composed of two-layer collagen sponges with preconfluent cells.

Although various kinds of cultured skin substitutes have been developed, it takes several weeks to produce them before grafting. In their previous study, the authors succeeded in producing cultured skin easily in a short period of time by layering two collagen sponges. In the current study, to shorten this period even further, they grafted the cell-preconfluent artificial skin immediately after seeding the cells. They used two collagen sponges with different pore sizes and crosslink densities. They seeded 1,000,000 cells per square centimeter of fibroblasts and 1,000,000 cells per square centimeter of keratinocytes on the respective collagen sponges and grafted them on a full-thickness, excised wound on the back of severe combined immunodeficient mice. Two weeks after grafting, epithelium and dermislike tissue were formed. They then decreased the number of keratinocytes and grafted them. Four weeks after grafting, at seeding densities of 50,000 to 1,000,000 cells per square centimeter of keratinocytes, the preconfluent artificial skin took histologically, and human type IV and type VII collagen were stained immunohistochemically. This cell-preconfluent artificial skin composed of two-layer collagen sponges seems promising for widespread clinical use.

Animals↗
PubMed2001

Spinal injuries in snowboarders: risk of jumping as an integral part of snowboarding.

BACKGROUND: The purpose of this study was to clarify the occurrence rate and characteristics of spinal injuries caused by snowboarding that were sustained at the Okumino skiing area in Gifu Prefecture, Japan, from 1988 to 2000. METHODS: This study was a retrospective review of 13,490 cases of snowboard- or ski-related injury treated at Sumi Memorial Hospital over this period. RESULTS: A total of 7,188 patients sustained snowboard-related injuries, and 238 of these had spinal injuries caused by snowboarding (3.3%), whereas 6,302 patients sustained ski-related injuries, and 86 of these had spinal injuries caused by skiing (1.4%). Although there were no significant differences in the difficulty of slope, location of vertebral fracture, or spinal cord injury between snowboarders and skiers, the incidence of transverse process fractures was significantly higher in snowboard-related than in skiing-related injury (p < 0.05). In addition, there was a significantly higher incidence of spinal injury among beginner snowboarders than among beginner skiers (p = 0.04). Furthermore, intermediate or expert snowboarders were more likely to be injured because of jumping than beginners (p < 0.001), whereas about 70% of spinal injuries caused by skiing resulted from a simple fall. CONCLUSION: Spinal injuries sustained while snowboarding are increasing considerably in incidence and are characterized as complex injuries. We must educate young snowboarders of the risk of this sport, to prevent these serious injuries.

Adolescent↗
PubMed2001

Induction of MMP-9 in normal human bronchial epithelial cells by TNF-alpha via NF-kappa B-mediated pathway.

In this study, we determined whether the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin-1 beta contribute to the regulation of matrix metalloproteinase (MMP)-9 in human bronchial epithelial cells and whether the induction of MMP-9 is regulated by the transcription factor nuclear factor (NF)-kappa B. We demonstrated that TNF-alpha induced MMP-9 at both the protein and mRNA levels in human bronchial epithelial cells and that interleukin-1 beta did not. In contrast, induction of the tissue inhibitor of metalloproteinase-1 by TNF-alpha was less than that of interleukin-1 beta. Increased expression of MMP-9 and NF-kappa B activation induced by TNF-alpha were inhibited by pyrrolidine dithiocarbamate and N-acetyl-L-cysteine but were not inhibited by curcumin. These results suggest that TNF-alpha induces the expression of MMP-9 in human bronchial epithelial cells and that this induction is mediated via the NF-kappa B-mediated pathway.

Acetylcysteine↗
PubMed2001

Ionic mechanisms underlying burst firing of layer III sensorimotor cortical neurons of the cat: an in vitro slice study.

We examined the ionic mechanisms underlying burst firing in layer III neurons from cat sensorimotor cortex by intracellular recording in a brain slice. Regular spiking was observed in 77.4% of 137 neurons in response to constant intracellular current pulses of 0.5- to 1-s duration. The rest of the neurons showed burst firing. An initial burst followed by regular-spike firing was seen in 71.0% of 31 bursting neurons. The rest of the bursting neurons (n = 9) exhibited repetitive bursting. In the bursting neurons, spikes comprising the burst were triggered from the afterdepolarization (ADP) of the first spike of the burst. We examined the ionic mechanisms underlying the ADP by applying channel-blocking agents. The ADP was enhanced (rather than blocked) by Ca2+ channel blockade. This enhancement of the ADP by Ca2+ channel blockade was apparent even after blockade of the afterhyperpolarization by apamin or intracellular Ca2+ chelation by EGTA. The firing rate of the regular-spiking cells was increased by apamin, intracellular EGTA or Ca2+ channel blockers. In 17.9% of the neurons examined (n = 56), these agents switched the regular-spiking pattern into a bursting one. Burst firing could not be changed to regular spiking by these agents. Four neurons that responded with a single initial burst in control solution responded with repetitive bursting after application of these agents. We conclude that the main function of Ca2+ influx in layer III neurons is to activate Ca2+-dependent K+ conductance, which prevents or limits burst firing. At a time when spike amplitude was unchanged, the ADP was blocked and the burst firing changed to regular spiking by extracellularly applied tetrodotoxin (TTX) or intracellularly applied N-(2,6-dimethylphenylcarbamoylmethyl) triethyl ammonium bromide (QX314). We concluded that a TTX- and QX314-sensitive Na+ current underlies the ADP and therefore contributes to the burst firing of layer III neurons from the cat cortex.

Action Potentials↗
PubMed2001

Bronchial hyperresponsiveness and exhaled nitric oxide in patients with cardiac disease.

BACKGROUND: Increased concentrations of exhaled nitric oxide (NO) correlate with increased airway inflammation and measurement of exhaled NO is a noninvasive method for the management of bronchial asthma. In various cardiac diseases, bronchial hyperresponsiveness is observed, as is bronchial asthma. However, there have been few studies on the relationship between exhaled NO and bronchial responsiveness in cardiac diseases. OBJECTIVE: The aim of this study was to clarify the association between exhaled NO and bronchial hyperresponsiveness in patients with cardiac disease. METHODS: We measured expired NO and bronchial responsiveness to inhaled methacholine in 19 patients with cardiac diseases and 17 with bronchial asthma. We divided the cardiac disease patients into two groups according to their bronchial responsiveness to inhaled methacholine: BHR(+) group consisted of 12 patients with bronchial hyperresponsiveness and BHR(-) group consisted of 7 patients without bronchial hyperresponsiveness. RESULTS: The concentration of exhaled NO in the asthmatic patients was significantly higher than that in the BHR(+) and BHR(-) groups (142.0 +/- 17.0, 33.6 +/- 6.4 and 42.3 +/- 10.3 ppb, respectively, p < 0.01). There was no significant difference in exhaled NO between BHR(+) and BHR(-) groups. There were also no significant differences in the parameters of bronchial hyperresponsiveness between the cardiac BHR(+) and bronchial asthma groups. These results indicate that bronchial hyperresponsiveness in patients with cardiac diseases is not a consequence of eosinophilic inflammation or of exhaled NO. CONCLUSION: We conclude that bronchial hyperresponsiveness in patients with cardiac diseases can occur independently of NO production.

Adult↗
PubMed2001

Crucial role of calpain in hypoxic PC12 cell death: calpain, but not caspases, mediates degradation of cytoskeletal proteins and protein kinase C-alpha and -delta.

Ca2+ influx is one of the main causative events in hypoxic PC12 cell death, because an extracellular Ca2+ chelator, ethylene glycol bis (2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) inhibited and Ca2+ ionophore A23187 mimicked the hypoxic cell death. The hypoxic cell death was markedly prevented by a broad spectrum caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (z-VAD-FMK) as well as a calpain inhibitor, calpeptin, as assessed by nuclear staining with Hoechst 33258 and lactate dehydrogenase release. The processing of procaspase-3 was inhibited by z-VAD-FMK, but not by calpeptin. In contrast, z-VAD-FMK failed to block the proteolytic cleavage of fodrin-alpha, a preferential substrate for calpain. On the other hand, degradation of actin and fodrin-alpha was prevented by calpeptin but not by z-VAD-FMK. In addition, not only protein kinase C (PKC)-alpha but also PKC-delta were cleaved to generate approximately 46 kDa fragments. The PKC fragmentation was inhibited by calpeptin but not by z-VAD-FMK. These findings suggest that the extracellular Ca2+ influx induced by hypoxic stress activates calpain, resulting in the degradation of cytoskeletal proteins and generation of PKC fragments almost independently of caspase activation. Therefore, calpain may play an important role in hypoxic PC12 cell death.

Animals↗
PubMed2001

The clinical utility of contrast-enhanced 3D MR angiography for cerebrovascular disease.

The purpose of this study was to evaluate the usefulness of contrast-enhanced 3D MR angiography (CE-MRA) with an automated bolus-detection algorithm (SmartPrep technique) and the specialized phased-array coils for the patients suspected cerebrovascular disease. Forty-three patients with brain attack were examined with CE-MRA. A tracker volume of SmartPrep technique was placed along the ascending aorta in the coronal image. After the bolus injection of gadolinium, an increase in signal that corresponded to the arrival of gadolinium was used to trigger centric re-ordered spoiled gradient echo arterial selective MRA with imaging time of 20-40 sec. We were able to achieve a 100% successful triggering rate of SmartPrep technique and selectively arterial-phase carotid and vertebral arteries with almost no venous contamination could be delineated. These techniques enabled high resolution imaging of entire craniocervical arteries from aortic arch to the circle of Willis. This CE-MRA was useful to evaluate both occlusion of arteries and the collateral pathways and to measure stenosis and residual flow of dissection accurately. CE-MRA was a reliable less-invasive alternative to investigate the patients of cerebrovascular disease.

Brain↗
PubMed2001

Peripheral administration of an angiotensin II AT(1) receptor antagonist decreases the hypothalamic-pituitary-adrenal response to isolation Stress.

Angiotensin II, which stimulates AT(1) receptors, is a brain and peripheral stress hormone. We pretreated rats with the AT(1) receptor antagonist candesartan for 13 d via sc-implanted osmotic minipumps, followed by 24-h isolation in individual metabolic cages. We measured angiotensin II receptor-type binding and mRNAs and tyrosine hydroxylase mRNA by quantitative autoradiography and in situ hybridization, catecholamines by HPLC, and hormones by RIA. Isolation increased AT(1) receptor binding in hypothalamic paraventricular nucleus as well as anterior pituitary ACTH, and decreased posterior pituitary AVP. Isolation stress also increased AT(1) receptor binding and AT(1B) mRNA in zona glomerulosa and AT(2) binding in adrenal medulla, adrenal catecholamines, tyrosine hydroxylase mRNA, aldosterone, and corticosterone. Candesartan blocked AT(1) binding in paraventricular nucleus and adrenal gland; prevented the isolation-induced alterations in pituitary ACTH and AVP and in adrenal corticosterone, aldosterone, and catecholamines; abolished the increase in AT(2) binding in adrenal medulla; and substantially decreased urinary AVP, corticosterone, aldosterone, and catecholamines during isolation. Peripheral pretreatment with an AT(1) receptor antagonist blocks brain and peripheral AT(1) receptors and inhibits the hypothalamic-pituitary-adrenal response to stress, suggesting a physiological role for peripheral and brain AT(1) receptors during stress and a possible beneficial effect of AT(1) antagonism in stress-related disorders.

Adrenal Cortex Hormones↗
PubMed2001

Effects of nipradilol, a nitric oxide-releasing beta-adrenoceptor blocking agent, on phosphoenolpyruvate carboxykinase gene transcription in a rat hepatoma cell line.

Effects of nipradilol, a beta-adrenoceptor blocker with a nitroxy moiety, on phosphoenolpyruvate carboxykinase (PEPCK) gene transcription were examined using a rat hepatoma cell line, H4IIE cells. Dexamethasone was employed as an enhancer of PEPCK gene transcription. Nipradilol, but not timolol (a beta-blocker without a nitroxy moiety), attenuated PEPCK gene transcription both in the control and the dexamethasone-treated cells. The effects of nipradilol were eradicated by methylene blue (an inhibitor of cellular guanylate cyclase). Nipradilol is a unique beta-blocker that suppresses PEPCK gene transcription in hepatocytes likely through liberation of nitric oxide and resultant activation of guanylate cyclase.

Adrenergic beta-Antagonists↗
PubMed2001

Bioassay for neutron-dose estimations of three patients in the JCO criticality accident in Tokai-mura by measuring beta-ray emitters.

The measurement of beta-emitters in biological samples (hair, urine and bone) from three patients in the JCO criticality accident was performed to assess the neutron dose to individuals. The result of the measurements of 32P in hair and urine collected immediately after the accident showed that sufficient 32P activities had been induced in the hair by fast neutrons and in the urine by thermal neutrons to know the severity of the exposure to the individuals and to the position. From the measurement of 32P and 45Ca in bone from various anatomical parts of two patients who died 82 and 210 days after the accident, it was suggested that the distribution of the induced beta-emitters activities could prove the position and posture of the patients at the moment of exposure.

Beta Particles↗