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Biomedical subjects

Y Ohashi

Publications and source records attributed to Y Ohashi.

At least 235 records · Page 13Linked to original sources
PubMed1998

Prolongation of allograft survival by administration of mAb specific for the three subunits of IL-2 receptor.

The IL-2 receptor (IL-2R) gamma chain, the so-called common gamma (gamma(c)) chain, which is shared with multiple cytokine receptors, plays important roles in the immune system. Here we assessed the immunosuppressive ability of mAb specific for the gamma(c) chain in induction of cytotoxic T lymphocytes (CTL) and allograft rejection in combination with mAb specific for the alpha and beta chains of IL-2R. CBA/N (H-2k) mice were injected i.p. with allogeneic splenocytes from BALB/c (H-2d) mice, and then administered with combinations of anti-IL-2R alpha, anti-IL-2R beta and anti-gamma(c) mAb or a control mAb. Addition of anti-gamma(c) mAb together with anti-IL-2R alpha and anti-IL-2R beta mAb induced a complete inhibition of CTL response. The numbers and populations of CD4+ CD8- and CD4- CD8+ T cells were not significantly affected by administration of the three anti-IL-2R mAb, whereas NK cells were completely depleted in spleens of mice treated with the anti-IL-2R mAb. Furthermore, skin allograft survival was also significantly prolonged by administration of the three anti-IL-2R mAb. These results suggest that the anti-gamma(c) mAb in combination with anti-IL-2R alpha and anti-IL-2R beta mAb is capable of suppressing induction of CTL and NK cells, resulting in prolongation of skin allograft survival.

Animals↗
PubMed1998

Defective intracellular transport of tissue-nonspecific alkaline phosphatase with an Ala162-->Thr mutation associated with lethal hypophosphatasia.

We have studied the biosynthesis and intracellular transport of tissue-nonspecific alkaline phosphatase (TNSALP) transiently expressed in COS-1 cells. Mutations were introduced into TNSALP to examine the effects of a single amino acid substitution on the activity and biosynthesis of TNSALP. The cells expressing wild-type TNSALP exhibited more than 200-fold higher alkaline phosphatase activity than untransfected ones. Pulse-chase experiments showed that TNSALP was synthesized as a 66-kDa endoglucosaminidase H (Endo H)-sensitive form and converted to EndoH-resistant forms with heterogenous molecular masses ( approximately 80 kDa), which finally appeared on the cell surface as judged by digestion with phosphatidylinositol-specific phospholipase C (PI-PLC). In contrast, a TNSALP with a Glu218-->Gly mutation exhibited no phosphatase activity at all and the 66-kDa Endo H-sensitive form was the only molecular species throughout the chase in the transfected cells. In accordance with this finding, digestion with PI-PLC and immunofluorescence observation confirmed that this mutant was never expressed on the cell surface. Another mutant with a Ala162-->Thr substitution, which naturally occurs in association with a lethal hypophosphatasia, exhibited a low activity and only a small fraction of the 66-kDa form acquired Endo-H resistance and reached the cell surface. Since the wild-type and the mutant TNSALPs were labeled with [3H]ethanolamine, a component of glycosylphosphatidylinositol (GPI), it is unlikely that the impaired intracellular transport of the two mutants is due to a failure in their modification by GPI. Interestingly, the 66-kDa Endo H-sensitive form of the TNSALP mutants but not that of the wild-type, was found to form an interchain disulfide-bonded high-molecular-mass aggregate within the cells. These results suggest that impaired intracellular transport of the TNSALP (Ala162-->Thr) molecule caused by its aggregation is the molecular basis for the lethal hypophosphatasia carrying this mutation.

Alanine↗
PubMed1998

Enhanced expression of an antimicrobial peptide sarcotoxin IA by GUS fusion in transgenic tobacco plants.

To enhance the disease resistance of plants expressing a foreign peptide, the gene for sarcotoxin IA, which is an antimicrobial peptide from an insect consisting of 39 amino acid residues, was introduced into tobacco (Nicotiana tabacum) under the control of a high expression promotor via Agrobacterium-mediated transformation. In transgenic plants, sarcotoxin IA mRNA accumulated to detectable levels, however, the amount of the peptide produced was so small that we could scarcely detect it by protein gel blot analysis, probably because of the instability of short peptides in plant cells. To improve the expression efficiency, genes for four types of amino-terminal and carboxyl-terminal translational fusions of sarcotoxin IA together with the GUS gene were introduced into tobacco. In all four types of transgenic tobacco plants, high level transcripts similar to that in the direct expression sarcotoxin IA construct were found. Protein gel blot analysis with both anti-sarcotoxin IA and GUS antibodies showed production of high levels of fusion protein in all transgenic plants. Among them, three types had abnormal membranes and phenotypes, although no such abnormalities were found in transgenic plants in which only sarcotoxin IA was expressed in a secretable form. All together, these results indicated that, for stable and effective expression of a foreign short peptide in transgenic plants, expression as a fusion protein is useful and that secretion of sarcotoxin IA outside of cells is necessary for generation of useful antimicrobial transgenic plants.

Anti-Bacterial Agents↗
PubMed1998

Nonadditivity of mutational effects on the properties of catalase I and its application to efficient directed evolution.

Catalase I of Bacillus stearothermophilus has high catalatic and low peroxidatic activities. The mutant from the first random mutant population, D130N, which has higher peroxidatic and lower catalatic activities than those exhibited by the wild-type enzyme, was subjected to second random mutagenesis in observance of the change in reaction specificity. From the second mutant population, the mutant I108T/D130N/I222T was selected and examined. The reaction specificity of the purified enzymes revealed that catalase I being originally 98% catalase and 2% peroxidase was brought to 58% specificity to peroxidase after two-step adaptive walks. From the statistical analysis of the two random mutant populations, the average degree of nonadditivity of the mutational effects was estimated to be 0.13 irrespective of the properties of the enzyme. It was demonstrated that the distribution pattern of a property of the second mutant population can be predicted well from the data of the first mutant population by taking into consideration the degree of nonadditivity. The strategy for an efficient adaptive walk in directed evolution of enzymes through the prediction of appropriate mutation rate and effective sample size for further mutation and selection was presented and discussed.

Catalase↗
PubMed1998

Immunotherapy decreases seasonal rise in serum-soluble CD23 in seasonal allergic rhinitis.

There is increasing in vitro evidence that soluble CD23 (sCD23) is capable of potentiating IgE synthesis, but the in vivo physiologic significance remains to be established. This study investigated the seasonal changes in sCD23 in patients with seasonal allergic rhinitis. It included 112 adult patients with seasonal allergic rhinitis due to Japanese cedar pollens and 20 nonatopic healthy volunteers. The 64 patients of the pharmacotherapy group were treated with nonsedating antihistamine tablets alone throughout the pollen season and the remaining 48 patients of the immunotherapy group continued to be treated with immunotherapy. Serum concentrations of sCD23 were measured in each patient, before and during the pollen season of 1996, by a sandwich enzyme-linked immunosorbent assay. The serum levels of sCD23 in the pharmacotherapy group before the pollen season were significantly higher than those in the nonatopic group (P = .0130) and those in the immunotherapy group (P = .0316). Seasonal increase in sCD23 was significant in the pharmacotherapy group, irrespective of the clinical response (P < .0001). By contrast, sCD23 was not significantly increased in the good responders to immunotherapy (P = .1826), but was significantly increased in the poor responders to immunotherapy (P = .0052). A significant correlation between seasonal increase in rate in specific IgE and seasonal increase in rate in sCD23 was confirmed in both the pharmacotherapy group (rs = 0.321, P = .0107) and the immunotherapy group (rs = 0.474, P = .0012). In conclusion, seasonal rise in sCD23 is associated with and is probably involved in seasonal rise in specific IgE in patients with seasonal allergic rhinitis, and successful immunotherapy is capable of blunting seasonal increase in sCD23, thus resulting in attenuation of seasonal increase in specific IgE and clinical benefits during the pollen season.

Adult↗
PubMed1998

Spermine is a salicylate-independent endogenous inducer for both tobacco acidic pathogenesis-related proteins and resistance against tobacco mosaic virus infection

Intercellular spaces are often the first sites invaded by pathogens. In the spaces of tobacco mosaic virus (TMV)-infected and necrotic lesion-forming tobacco (Nicotiana tabacum L.) leaves, we found that an inducer for acidic pathogenesis-related (PR) proteins was accumulated. The induction activity was recovered in gel-filtrated fractions of low molecular mass with a basic nature, into which authentic spermine (Spm) was eluted. We quantified polyamines in the intercellular spaces of the necrotic lesion-forming leaves and found 20-fold higher levels of free Spm than in healthy leaves. Among several polyamines tested, exogenously supplied Spm induced acidic PR-1 gene expression. Immunoblot analysis showed that Spm treatment increased not only acidic PR-1 but also acidic PR-2, PR-3, and PR-5 protein accumulation. Treatment of healthy tobacco leaves with salicylic acid (SA) caused no significant increase in the level of endogenous Spm, and Spm did not increase the level of endogenous SA, suggesting that induction of acidic PR proteins by Spm is independent of SA. The size of TMV-induced local lesions was reduced by Spm treatment. These results indicate that Spm accumulates outside of cells after lesion formation and induces both acidic PR proteins and resistance against TMV via a SA-independent signaling pathway.

Journal Article↗
PubMed1998

Proliferative fasciitis of the forearm: case report with immunohistochemical, ultrastructural and DNA ploidy studies and a review of the literature.

A case of proliferative fasciitis arising in the left forearm of a 56-year-old man was examined. The lesion was preceded by blunt trauma, measured 1.5 x 1.3 x 1.0 cm, was poorly circumscribed and appeared white to light gray on the cut surface. Light microscopic examinations revealed that spindle cells and giant cells with one or two nuclei and abundant basophilic cytoplasm were arranged without any organized patterns in collagenous stroma. Ultrastructurally, well-developed rough endoplasmic reticulum separated by varying amounts of fine to course fibrillar materials was detected in the giant cells. Only vimentin immunoreactivity was detected in both spindle and giant cells. The Ki-67 labeling index of spindle cells was 35% but that of giant cells was less than 5%, and this reflects the quiescent or slow-growing features of these giant cells in proliferative fasciitis. DNA content of the cells, which was examined by image cytometry, demonstrated diploidy in both spindle (DNA index=1.01) and giant (DNA index=1.09) cells.

Cell Division↗
PubMed1998

Nonfunctioning adrenal cortical cancer and analysis of the steroidogenic activity of the tumor: a case report.

An adrenocortical cancer was detected by a CT scan in a 37-year-old woman, which did not have an excessive secretion of steroids or catecholamines. The tumor was enhanced inhomogeneously by the bolus injection of contrast medium, and magnetic resonance imaging (MRI) showed that the tumor was hypointense compared to the liver on a T1-weighted image and was diffusely hyperintense on a T2-weighted image. Histologically, the tumor consisted predominantly of compact cells with marked cellular and nuclear pleomorphism, but no capsular or vascular invasion were observed. An analysis of the steroidogenic activity of the tumor revealed that the activity of mitochondrial P450c11beta was extremely reduced in the tumor.

Adrenal Cortex Neoplasms↗
PubMed1998

Effects of platelet activating factor on the tubotympanic mucosa and inner ear in the guinea pig.

The effect of platelet activating factor (PAF) was studied to elucidate its role in the pathogenesis of otitis media and sensorineural hearing loss. The PAF alone did not induce a reduction of ciliary activity of the cultured middle ear mucosa. However, a dose-dependent decrease in ciliary activity was observed in the presence of the medium containing both PAF and macrophages. Intravenous injection of PAF did not induce dysfunction of the mucociliary system or morphologic changes of epithelium in the tubotympanum, but cytoplasmic vacuolization and ballooning were observed in the inner ear within 1 hour after injection of PAF. In contrast, intratympanic injection of PAF induced mucociliary dysfunction and some pathologic changes in the tubotympanum. Intratympanic inoculation of PAF induced no pathologic findings in the inner ear. These results suggest that PAF is at least partially involved in the pathogenesis of certain middle ear diseases such as otitis media with effusion. Additionally, PAF might be involved in the pathogenesis of some types of unexplained sensorineural hearing loss.

Animals↗
PubMed1998

Detection of the PGP9.5 and tyrosine hydroxylase mRNAs for minimal residual neuroblastoma cells in bone marrow and peripheral blood.

The "touchdown" polymerase chain reaction (PCR) technique has been applied to analyze expression of the neuron-specific protein, PGP9.5, and tyrosine hydroxylase (TH) genes for detection of minimal residual neuroblastoma cells in bone marrow and peripheral blood. PGP9.5 and TH gene products were not detected in any normal samples (n = 72) examined. However, in patients more than 1 year of age with stage III and IV neuroblastoma PGP9.5 mRNA was detected in six of seven bone marrow samples and in four of eight peripheral blood samples, and TH mRNA in four of seven and three of eight, respectively. The detection sensitivity was up to 10(-6) to 10(-7) micrograms of total cellular RNA for PGP9.5 and 10(-4) micrograms for TH. Among forty bone marrow specimens from nineteen patients with neuroblastoma both PGP9.5 and TH mRNAs were detected in six, and only PGP9.5 mRNA was detected in ten. Since detection of PGP9.5 and TH gene transcripts by the "touchdown" PCR was highly specific and sensitive, it might be most informative at present to carry out both PGP9.5 and TH mRNA assays for minimal residual neuroblastoma cells in blood and bone marrow.

Bone Marrow↗
PubMed1998

Immunocytochemical demonstration of the synovial membrane in experimentally induced arthritis of the rat temporomandibular joint.

The present study is first to report an experimental model of adjuvant-induced arthritis in the rat temporomandibular joint (TMJ). Arthritis was induced by simultaneous intradermal administrations of Freund's complete adjuvant, one at the parietal scalp and the other at the base of the tail. In this model, we demonstrated responses of the synovial membrane by immunocytochemistry using antibodies to OX6 and ED1 which recognize Ia antigen in MHC class II antigen-expressing cells and the macrophage/monocyte lineage, respectively. Three weeks after administration, no remarkable signs of inflammation were macroscopically recognizable in the TMJ, but microscopically the synovial membrane in the TMJ revealed marked changes such as enhanced vascularization and hemostasis in the sublining layer and a thickening in the synovial lining cell layer. Intense OX6-immuno-reactivity was found in the synovial lining cells at lesions in the experimental group but not in the control group. Immunoelectron microscopy revealed that these OX6-immunopositive synovial lining cells developed dense cytoplasmic processes and numerous vacuoles and vesicles, resembling type A cells. Part of the type A cells also showed ED1-immunoreactivity. The expression of OX6 or ED1 immunoreactivity in the synovial lining cells might be involved in the initial immune responses in this arthritis model because the synovial membranes are exposed to the synovial fluids which have been believed to contain antigenic substances.

Animals↗
PubMed1998

Intradural retroclival chordoma without bone involvement: no tumor regrowth 5 years after operation. Case report.

Chordomas are most commonly located in the extradural region. A 56-year-old man presented with a large chondroid chordoma located totally within the intradural retroclival region. The tumor was resected via the petrosal approach. Five years after subtotal removal, the residual tumor showed no sign of regrowth despite the fact that radiation therapy had not been used. The patient was free of symptoms except for moderate, conductive hearing loss in his right ear. The position of the intradural tumor could be preoperatively diagnosed by neuroimaging and, thus, the petrosal approach was selected. Primary intradural extraosseous chordomas are very rare and difficult to differentiate from ecchordoses physaliphorae on the basis of histological and radiological features; however, MIB-1 staining may be useful.

Chordoma↗
PubMed1998

A new anti-MRSA antibiotic complex, WAP-8294A. I. Taxonomy, isolation and biological activities.

WAP-8294A, produced by Lysobacter sp., is a complex consisting of water soluble depsipeptide antibiotics. It was further purified by column chromatographies and HPLC, and 19 components were obtained. WAP-8294A2, a major component, and minor components A1, A4, Ax8, Ax9 and Ax13 were active against gram-positive bacteria, in particular, methicillin-resistant Staphylococcus aureus (MRSA) in vitro. WAP-8294A2 was highly active in vivo in mice against the systemic infection of MRSA.

Animals↗
PubMed1998

[Reproducibility and validity of a semi-quantitative food frequency questionnaire].

The reproducibility and relative validity of a semi-quantitative food frequency questionnaire (FFQ) were evaluated. Subjects were 72 (36 men and 36 women) residents of N island, Shimane Prefecture in Japan, aged 50-76 years. The questionnaire was administered twice at an interval of one week (FFQ1, FFQ2), and 7-day weighing diet records were collected during that period. This protocol was conducted in summer and winter. The mean intakes for 11 nutrients calculated from the FFQ1 and FFQ2 were similar and, those from the FFQ1 were smaller than those from the diet records for all but fat and vitamin C. Pearson correlation coefficients assessing reproducibility between nutrient intakes from FFQ1 and FFQ2 ranged from 0.59 for vitamin C to 0.90 for carbohydrate. Validity was measured by comparing nutrient intakes from FFQ1 with those from the 7-day diet record, and Pearson correlation coefficients ranged from 0.15 for iron to more than 0.35 for total energy and macronutrients. These correlation coefficients showed slight difference by gender or age group, but did not vary materially between seasons. These data indicate that this questionnaire is reproducible but has some problems in validity.

Aged↗
PubMed1998

University medical information network--past, present, and future.

The University Medical Information Network (UMIN), established in 1989, is a network service organization for national university hospitals in Japan. It has provided various medical information services to medical professionals, including database, electronic mail, and news services. Although its initial network was constructed as a closed network using N1 protocol, it now adopts TCP/IP protocol and is open to other medical professionals via the Internet. The next UMIN network system is planned to be constructed as a secure virtual closed network on the Internet, using cipher technology, and to provide secure information services to national university hospitals via the closed network, and to other medical professional via the Internet. User friendly interface and flexible system development were made possible by adopting TCP/IP, and the number of users dramatically increased accordingly. However, the database, software design, and human organizations developed in the N1 era have now proven to be of great value, and contribute to todayís flourishing state of the UMIN.

Computer Communication Networks↗
PubMed1998

[The mechanism of corneal epithelial disorder induced by prostaglandin F2 alpha isopropyl unoprostone].

Deleterious effects of isopropyl unoprostone (PG-F2 alpha) on the ocular surface were evaluated using the in vivo barrier function assay of corneal epithelial cells and the proliferation assay of human corneal epithelial cells in vitro. The barrier function of corneal epithelial cells in vivo was not impaired by treatment with PGF2 alpha, but it was significantly suppressed by timolol. The result of cell proliferation assay of human corneal cells showed that the 0.12% PGF2 alpha ophthalmic solution caused greater suppression of cell proliferation and acuter cell toxicity than 0.5% timolol ophthalmic solution. Further study showed that not the vehicle but the PGF2 alpha itself was responsible for these deleterious effects. We conclude that the 0.12% PGF2 alpha ophthalmic solution affects cell migration and proliferation but not the barrier effects of the ocular surface. These results suggest that the corneal epithelial defect of glaucoma patients may be caused by these two independent mechanisms, namely suppression of cell proliferation by PGF2 alpha and the destruction of the barrier function of the ocular surface by timolol.

Adrenergic beta-Antagonists↗
PubMed1998

Cardiovascular effects of (2RS,3SR)- 2-aminomethyl-2,3,7,8-tetrahydro-2,3,5,8,8-pentamethyl-6H-furo- [2,3-e]indol-7-one hydrochloride (UK-1745), a novel cardiotonic agent with vasodilatory and antiarrhythmic properties.

The cardiovascular effects of (2RS,3SR)-2-aminomethyl-2,3,7,8- tetrahydro-2,3,5,8,8-pentamethyl-6H-furo[2,3-e]indol-7-one hydrochloride (CAS 170684-14-7, UK-1745), a novel cardiotonic agent, were investigated using in vitro and in vivo preparations. In paced left atria isolated from guinea pigs, both UK-1745 and vesnarinone (CAS 81840-15-5) showed a concentration-dependent positive inotropic effect. In spontaneously beating guinea pig right atria, both agents caused only a minimal chronotropic effect. In isolated, blood-perfused canine papillary muscle preparations, UK-1745 and vesnarinone injected intra-arterially into the anterior septal artery (ASA) increased the developed tension in a dose-dependent manner. In isolated, blood-perfused canine sinoatrial node preparations, both agents injected into the right coronary artery (RCA) did not cause any appreciable changes in the sinus rate. UK-1745 increased the blood flow through the ASA and the RCA in a dose-dependent manner, whereas vesnarinone did not. In anesthetized open-chest dogs, UK-1745 injected intravenously increased cardiac contractility and cardiac output, and decreased left ventricular end-diastolic pressure, systemic vascular resistance and heart rate. In experimentally induced acute heart failure in anesthetized open-chest dogs, intravenously injected UK-1745 effectively improved hemodynamic functions. In conscious instrumented dogs, orally administered UK-1745 increased LV dP/dtmax with insignificant changes in systemic blood pressure and heart rate. In mice, orally administered UK-1745 protected the development of ventricular fibrillation induced by chloroform inhalation, whereas vesnarinone did not. Thus, in respect of inotropic and chronotropic effects, UK-1745 closely resembled vesnarinone, but differed from vesnarinone in respect of coronary vasodilating and antiarrhythmic effects. The results suggest that UK-1745 is a novel positive inotropic agent with vasodilatory and antiarrhythmic properties, without significant chronotropic action, and may be beneficial for the treatment of congestive heart failure.

Anesthesia↗