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Biomedical subjects

Y Yamauchi

Publications and source records attributed to Y Yamauchi.

At least 19 recordsLinked to original sources
PubMed2006

Nematode infection in Alymphoplasia (aly) mice: worm species-dependent differential effect of defects of the gut-associated lymphatic tissue system.

Mice homologous for the alymphoplasia mutation (aly) show the systemic absence of secondary lymphoid tissues, with disorganized splenic architecture, including the absence of the germinal centre and follicular dendritic cells. In this study, we examined the influence of defects of gut-associated lymphoid tissue (GALT), such as Peyer's patches and the mesenteric lymph nodes, on the host response to helminth infection in aly/aly mice. The present study showed that most of the worms were expelled by day 7 after Nippostrongylus brasiliensis infection in both control aly/+ and aly/aly mice. In aly/aly mice, the number of peripheral blood eosinophils, intestinal goblet cells and mucosal mast cells were increased by N. brasiliensis infection in aly/aly mice to the same level as in the controls. Conversely, aly/aly mice developed more severe Heligmosomoides polygyrus infections than control aly/+ mice, as demonstrated by increased faecal egg counts, with reduced immune responses such as the numbers of intestinal goblet cells and mucosal mast cells. These results suggested that the dependency of GALT in activation of Th2 responses against gastrointestinal nematodes was different depending on the species of nematode.

Animals↗
PubMed2003

Spin dependence in the survival probability of metastable He (2(3)S) atoms during the scattering from ferromagnetic surfaces.

The use of a spin-polarized metastable helium (He(*)) atom beam has demonstrated that the survival probability (SP) of He(*) during the scattering from ferromagnetic surfaces depends on the electron spin of He(*). The spin asymmetry in the SP of He(*) scattered from a clean Fe/Cu(100) surface changed its polarity with H2O adsorption. We argue that the reversal is caused by the change in the spin polarization of the surface electronic states at around the Fermi level.

Journal Article↗
PubMed2002

Birth of normal calves after intracytoplasmic sperm injection of bovine oocytes: a methodological approach.

Intracytoplasmic sperm injection (ICSI) is advantageous when only very few spermatozoa are available for insemination. Bovine spermatozoa were injected individually into matured oocytes using a piezo electric actuator. Spermatozoa were "immobilized", by scoring their tails immediately before injection, or "killed", by repeated freezing and thawing. About 4 h after ICSI, the oocytes with two polar bodies (activated by sperm injection) were selected and treated 5 min with 7% ethanol before further culture. When examined 19-21 h after ICSI, nearly 90% of the oocytes were fertilized normally (two pronuclei and two polar bodies) irrespective of the sperm treatment (immobilization or killing) prior to ICSI, but subsequent preimplantation embryo development was much superior (cleavage 72%: blastocysts 20%) after ICSI with immobilized spermatozoa than by using killed spermatozoa (cleavage 28%; blastocysts 1%). Ethanol activation of bovine oocytes with two polar bodies 4 h after ICSI improved the cleavage (33% versus 72%) and blastocyst (12% versus 20%) rates markedly (P < 0.05). Five normal calves were born after transplantation of ten blastocysts to ten surrogate cows. These results show that piezo-ICSI using immobilized spermatozoa, combined with ethanol treatment of sperm-injected oocytes, is an effective method to produce bovine offspring.

Animals↗
PubMed2001

Use of digital subtraction fluoroscopy to diagnose radiolucent aspirated foreign bodies in infants and children.

OBJECTIVES: Most tracheobronchial foreign bodies in children are radiolucent, and accurate diagnosis of such foreign bodies is not always easy. This can result in delay of diagnosis or misdiagnosis of foreign body aspiration. We report the usefulness and pitfalls of use of digital subtraction fluoroscopy (DSF) to diagnose radiolucent aspirated foreign bodies in infants. METHODS: From 1991 through 1999, DSF was conducted for a total of 19 patients (ranged from 11 months to 4 years and 7 months in age (mean 1.8+/-0.9 years)) who were suspected to have radiolucent aspirated foreign bodies. Since DSF revealed abnormal findings in a trachea or main bronchus in 18 cases, inspection was performed for foreign body bronchofiberscopically. In the one remaining case, no abnormality was recognized on DSF, but since the symptoms at the time of onset strongly suggested aspirated foreign body, bronchofiberscopy was also performed. RESULTS: Foreign body was verified bronchoscopically in 13 of 19 cases, and all 13 (100%) had abnormal findings on DSF, including obstruction of the trachea in two, obstruction of the bronchial lumen in nine, and indistinct visualization of the bronchial lumen in two. Bronchial stenosis was verified bronchoscopically in five of the remaining six cases, including mucus plug in three, granuloma in one and mucosal edema in one case. All five patients (100%) had abnormal findings on DSF, including obstruction of the bronchial lumen in four and indistinct visualization of the bronchial lumen in one. In the one remaining patient with normal findings of DSF, no foreign body or pathological bronchial changes were noted. CONCLUSIONS: DSF was very sensitive in the diagnosis of foreign body aspiration and stenotic changes in the bronchial lumen. However, its diagnostic specificity for aspirated foreign body itself was not high (17%). Therefore, when abnormalities are found on DSF, we recommend to perform flexible bronchofiberscopy initially under general anesthesia via a tracheal tube. When a foreign body is verified, rigid ventilation bronchoscopy is successively performed to retrieve the foreign body.

Bronchi↗
PubMed2001

Spin polarized metastable He*(2(3)S, 1s2s) stimulated desorption of H(+) ions.

The yield of H(+) in the metastable He*(2(3)S, 1s2s) stimulated desorption (MSD) on an H2O/Na/Fe surface has been found to depend on the spin of the incident He*. By combination with the spin-resolved analysis for the surface electronic structure, it is indicated that the neutralization of the hole in the OH 3 sigma molecular orbital, which is created by the incident He*, by Na 3s electrons plays a crucial role in the spin polarization of the H (+) MSD intensity. The dependence of the spin polarization of H(+) MSD on the kinetic energy of the desorbed H(+) has been observed, and it is discussed based on the Menzel-Gomer-Readhead model.

Journal Article↗
PubMed2001

Role of parabrachial nucleus in submandibular salivary secretion induced by bitter taste stimulation in rats.

When rats lick a bitter taste solution such as quinine-hydrochloride, they secrete profuse amounts of saliva. The salivation has a higher flow rate than that induced by other qualities of taste stimulation: sweet, salty, and sour. The present study is aimed to clarify the neural mechanism of the quinine-evoked salivation by means of behavioral, neuroanatomical, and electrophysiological experiments. Behaviorally, submandibular salivary secretion and rejection behavior (gaping) were observed in normal rats, as well as in rats chronically decerebrated at the precollicular level. In chronically decerebrate rats, these quinine-evoked reactions were strongly suppressed by destruction of the medial part of the parabrachial nucleus, including the so-called taste area, and ventral part of the parabrachial nucleus, including the pontine reticular formation. Neuroanatomical study using a retrograde tracer, Fluoro-gold, revealed that the neurons sending their axons to the superior salivatory nucleus, parasympathetic secretory center, were located mainly in the pontine reticular formation ventral to the parabrachial nucleus, not in the parabrachial taste area. Extracellular neural activity was recorded from the parabrachial region in decerebrate rats, and responsiveness to taste stimulation, jaw movements, and electrical stimulation of the superior salivatory nucleus was examined. Neurons responsive to both taste stimulation and antidromic stimulation of the superior salivatory nucleus were found in the pontine reticular formation ventral to the parabrachial nucleus, which responded well to quinine and HCl taste stimuli. Neurons in the parabrachial taste area could respond to four qualities of taste stimulation, but not to antidromic stimulation of the salivary center. These results suggest that aversive taste information from the parabrachial taste area reaches the salivary secretory center via the reticular formation ventral to the parabrachial nucleus.

Animals↗
PubMed2001

Changes in gastrointestinal lymph and blood vessels in patients with cirrhotic portal hypertension.

BACKGROUND: The aim of this study was to characterize the lymph vessels in different parts of the gastrointestinal tract and also to evaluate morphometric changes in these vessels during cirrhotic portal hypertension. METHODS: Sixteen patients with cirrhotic portal hypertension and 18 control subjects without portal hypertension were enrolled in the study. Tissue specimens were collected at autopsy or surgery, and were stained enzyme histochemically, using 5'-nucleotidase and alkaline phosphatase to distinguish lymph vessels and blood vessels, respectively. The numbers of vessels and their luminal areas were estimated using computer graphics software (National Institutes of Health [NIH] image program). RESULTS: The numbers and luminal areas of the lymph vessels varied considerably among the different organs of the gastrointestinal tract, both in controls and in the patients with cirrhotic portal hypertension. There was no significant difference in the numbers of lymph vessels between controls and patients with cirrhotic portal hypertension. However, the luminal area of the lymph vessels in the esophagus and stomach was significantly greater in the patients with cirrhotic portal hypertension than in the controls. These differences in lymph vessels were not seen in the small intestine and colon. CONCLUSIONS: These data indicate that dilatation of lymph vessels may be related to the absorption of excess interstitial fluid, resulting from congestion, in cirrhotic portal hypertension.

5'-Nucleotidase↗
PubMed2001

Typing of Herpes Simplex Virus in Patients with Uveitis.

Aim: To examine the type of herpes simplex virus (HSV) in cases with uveitis.Materials and Methods: Intraocular fluid specimens obtained from 3 cases with herpetic iridocyclitis and 6 cases with acute retinal necrosis (ARN) were examined by polymerase chain reaction (PCR). HSV typing was performed by the restriction patterns of the PCR products. Serum samples obtained from these cases and 33 cases with uveitis were examined by neutralization test (NT) for the availability of the typing of HSV.Results: The restriction patterns of the PCR products amplified from 3 specimens of iridocyclitis revealed HSV type 1 DNA. HSV type 2 DNA was identified in 5 of 6 cases of ARN and HSV type 1 DNA was found in only one case. The results of serum NT titers correlated with the typing of the amplicons.Conclusions: In the cases studied, HSV type 1 was the dominant etiological agent in herpetic iridocyclitis, while HSV type 2 plated a similar role in HSV-associated ARN. The examination of the serum NT may be helpful for the identification of the etiological types of HSV in patients with uveitis.

Journal Article↗
PubMed2001

A serine endopeptidase from cucumber leaves is inhibited by L-arginine, guanidino compounds and divalent cations.

An endopeptidase was purified and characterized from green leaves of cucumber (Cucumis sativus L. suyo). The purified enzyme, a basic amino acid-specific endopeptidase with a pI of 5.0, was a monomeric protein of 80 kDa whose pH optimum was 9.5. Inhibitor analysis suggested that it was a serine endopeptidase and contained sulfhydryl groups essential for catalytic activity. Analysis of internal amino acid sequences of the endopeptidase showed no significant similarity to other proteins. Its activity was inhibited by L-Arg and guanidino compounds having high hydrophobicity, as well as divalent cations such as Mg2+ and Ca2+. The K(i) values of L-Arg and Mg2+, which are also likely in vivo inhibitors, were 3.5 and 10 mM, respectively. Inhibition by L-Arg and Mg2+ was additive, and more than 70% of the activity was reversibly inhibited under their physiologically significant concentrations. These results suggest that the enzyme is possibly regulated by L-Arg and/or guanidino compounds, and by divalent cations in vivo.

Agmatine↗
PubMed2001

Identification and characterization of the UL24 gene product of herpes simplex virus type 2.

The UL24 gene of herpes simplex virus type 2 (HSV-2) is predicted to encode a 281 amino acid protein with a molecular mass of 30.5 kDa. In this study, the HSV-2 UL24 gene product has been identified by using a rabbit polyclonal antiserum produced against a recombinant protein containing the full-length UL24 gene product of HSV-2 fused to glutathione-S-transferase. The antiserum reacted specifically with a 32 kDa protein in HSV-2 186-infected Vero cells and with 31 and 32 kDa proteins in UL24-expressing Cos-7 cells. Accumulation of UL24 protein to detectable levels required viral DNA synthesis, indicating that the protein was regulated as a late gene. UL24 protein was found to be associated with purified HSV-2 virions and C capsids. Indirect immunofluorescence analysis demonstrated that the UL24-specific fluorescence was detected in perinuclear regions of the cytoplasm and/or in the nucleus as small discrete granules from 9h post infection (hpi). Furthermore, the UL24 protein expressed singly was detected predominantly in the nucleus and slightly in the cytoplasm at 24 h after transfection, with branch-like cytoplasmic protruding structures. Strong nucleolus staining was visible in partial cells.

Animals↗
PubMed2001

Soluble thrombospondin-1 suppresses T cell proliferation and enhances IL-10 secretion by antigen presenting cells stimulated with phytohemagglutinin.

Thrombospondin-1 (TSP-1) is different from other components of the extracellular matrix (ECM) regarding its production and distribution. TSP-1 is considered to be released in large quantity in inflammatory sites and exogenously added TSP-1 does not bind to preformed ECM but instead binds to cells. To define the physiological role of TSP-1 in the immune system, we studied the influence of TSP-1 on the in vitro culture of T cells and antigen-presenting cells (APCs) in the presence of phytohemagglutinin. By adding soluble TSP-1 to the culture, T cell proliferation was suppressed and anti-inflammatory cytokine IL-10 secretion by APCs was enhanced. The enhanced expression of IL-10 was also demonstrated at the mRNA level by RT-PCR using multiprimer kit for cytokines. The suppression of T cell proliferation and the enhancement of IL-10 secretion with soluble TSP-1 was inhibited byadding RGDS peptide or heparin. This result indicates that the effect of soluble TSP-1 may be caused by binding to its ligand(s) on T cells and/or APCs, resulting in transducing regulatory signals to the cells or disturbing appropriate interaction between T cells and APCs. We therefore propose that TSP-1 is an immunosuppressive modulator which may play a role in inflammatory sites.

Antigen-Presenting Cells↗
PubMed2001

A high molecular weight glutamyl endopeptidase and its endogenous inhibitors from cucumber leaves.

We purified a glutamyl endopeptidase that is a major foliar endopeptidase in cucumber. The endopeptidase had a molecular mass of 400 kDa, consisted of four subunits of 97 kDa, and was inactivated by SH-modifying reagents. Its optimum pH and optimum temperature were 8.0 and 30-37 degrees C, respectively. An internal amino acid sequence of the endopeptidase was highly homologous to a partial sequence of unidentified proteins deduced from genetic information for Arabidopsis thaliana, soybean and rice, but not to the sequences of bacterial glutamyl endopeptidases or animal proteases. Therefore, the unidentified proteins might be glutamyl endopeptidases and be widely distributed only among plant species. The activity of the cucumber glutamyl endopeptidase was inhibited by at least three inhibitors existing in cucumber leaves. One of the inhibitors was a competitive inhibitor of 25 kDa, which did not significantly inhibit commercial endopeptidases derived from animals and microorganisms. This suggests that the cucumber glutamyl endopeptidase might be controlled by endogenous inhibitors in vivo.

Amino Acid Sequence↗
PubMed2001

Herpes simplex virus type 2 UL34 protein requires UL31 protein for its relocation to the internal nuclear membrane in transfected cells.

Herpes simplex virus type 2 UL34 protein is expressed late in infection and is required for envelopment of nucleocapsids at the nuclear membrane and possibly at the endoplasmic reticulum (ER). It is a type II membrane protein with a C-terminal anchor that localizes mainly to the nuclear membrane in infected cells. However, in single transient expression, UL34 protein localizes predominantly to the ER. Relocation of UL34 protein from the ER to the internal nuclear membrane and the nucleus was observed in the presence of UL31 protein, a phosphoprotein known to interact physically with UL34. It is suggested here that interaction with UL31 protein is important for the nuclear targetting of UL34 protein and also that the trans-membrane region of UL34 protein is responsible for its localization at the internal nuclear membrane. The results also suggest possible sites for the interaction.

Active Transport, Cell Nucleus↗
PubMed2001

Anodization in oligo(ethylene glycol) as an initial derivatization tool for preparing glassy carbon electrodes covalently modified with amino compounds: effective access to a 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-modified glassy carbon electrode.

Anodization in HO(CH2CH2O)nH (1a, n=2; 1b, n=3; 1c, n=4) as an initial derivatization tool for preparing glassy carbon (GC) electrodes covalently modified with amino compounds was explored. As an amino compound to be immobilized, 4-amino-2,2,6,6-tetramethylpiperidinyl-1-oxyl (4-amino-TEMPO) was selected. When GC electrodes anodized at 2.0 V vs. Ag wire coated with AgCl in 1 containing RCH2CH2SO3Na (2a, R=H; 2b, R=OH) were treated with a N,N-dimethylformamide (DMF) or CH2Cl2 solution of 4-amino-TEMPO and 1,3-dicyclohexylcarbodiimide (DCC), TEMPO-modified GC electrodes were afforded. Coverage (gammaTEMPO) of the electrode surfaces by TEMPO was estimated by cyclic voltammetry in CH3CN containing NaClO4. A TEMPO-modified GC electrode with the best gammaTEMPO (1.36 x 10(-10) mol/cm2) was obtained by anodization in 1b containing 2a at the expense of 3.0 C followed by amidization in DMF for 7 d. On cyclic voltammetry, the TEMPO-modified GC electrode showed good and stable electrocatalytic ability for oxidation of allyl alcohol in the presence of 2,6-lutidine.

Carbon↗
PubMed2001

Hydrogen peroxide-induced deacetylation of acetyl resorufin as a novel indicator reaction for fluorometric detection of glucose using only glucose oxidase.

Hydrogen peroxide (H2O2)-induced deacetylation of non-fluorescent acetyl resorufin (1) to fluorescent resorufin (2) as a novel indicator reaction for fluorometric detection of glucose using only glucose oxidase (GOD) is described. When a 1:1:1 mixture of 1 (in CH3CN), glucose, and GOD (each in pH 7.4 phosphate buffer) was incubated at 25 degrees C under aerobic conditions, the resulting solution turned yellow to fluorescent pink due to 2. The formation of 2 was markedly retarded on incubation under anaerobic conditions. When a mixture of 1 and H2O2 was incubated under aerobic conditions, the formation of 2 was noted as in the case of the enzymatic reaction of 1. These results demonstrated that the observed color change is brought about through deacetylation of 1 to 2 induced by H2O2 generated in GOD-catalyzed oxidation of glucose. With regard to the fluorometric traces of the enzymatic reaction with 1 (0.2 mM), GOD (0.5 mg/ml), and glucose at 25 degrees C, fluorescence intensity exhibited a linear relationship against glucose concentration between 0.2 and 2.0 mm, with a correlation coefficient of 0.997. Neither ascorbic acid, uric acid, nor bilirubin significantly interfered with the transformation of 1 to 2 through GOD-catalyzed oxidation of glucose.

Ascorbic Acid↗