Biomedical subjects

T Hara

Publications and source records attributed to T Hara.

At least 397 records · Page 22Linked to original sources

PubMed1998

Basophilic differentiation of the human leukemia cell line KU812 upon treatment with interleukin-4.

The human leukemia cell line KU812 had been described as an immature prebasophilic cell line and exhibits a potential to differentiate into mature basophils. We studied the effect of interleukin-4 (IL-4) on the basophilic differentiation of KU812 cells. When KU812 cells were cultured with 1 ng/ml IL-4, cellular histamine content increased more than 10-fold. IL-4 also enhanced the expression of Fc epsilon RI alpha, a high affinity IgE receptor, on the cell surface. KU812 cells treated with IL-4 expressed higher levels of Fc epsilon RI alpha, Fc epsilon RI beta and Fc epsilon RI gamma mRNA than non treated KU812 cells. After 21 days in culture with IL-4, KU812 cells became morphologically mature basophilic cells as demonstrated by staining positive for cytoplasmic granules and heparin proteoglycan by Wright dye and toluidin blue dye respectively. In addition, IgE-mediated histamine release was observed, suggesting that the Fc epsilon RI induced by IL-4 was functional and was able to transduce a signal for degranulation. These results suggest that IL-4 promotes differentiation of KU812 cells into mature basophilic cells both morphologically and functionally.

Basophils↗

PubMed1998

A lipoprotein lipase activator, NO-1886, improves endothelium-dependent relaxation of rat aorta associated with aging.

Endothelial function is closely related to development of atherosclerosis and is impaired with aging. The novel compound NO-1886, 4-diethoxyphosphorylmethyl-N-(4-bromo-2-cyanophenyl)benzamid e, is a lipoprotein lipase activator and its long term administration protects against the development of experimental atherosclerosis in animals. The aim of this study was to ascertain whether NO-1886 ameliorates the impaired endothelium-dependent relaxation of rat aorta associated with aging. NO-1886 (50 mg/kg p.o.) was administered to 7-month old rats for 3 months. Plasma lipid, glucose and insulin levels in old control rats (10 months of age) were significantly higher than those of young rats (2 months of age). NO- 1886 decreased plasma triglyceride levels (old rats, 233+/-10 mg/dl; old rats + NO-1886, 172+/-16 mg/dl, P < 0.01) and increased plasma high density lipoprotein (HDL) cholesterol level (old rats, 72+/-6 mg/dl; old rats + NO-1886, 142+/-6 mg/dl, P < 0.001) in old rats, but had no effects on plasma glucose or insulin. The endothelium-dependent relaxation of the thoracic aorta caused by histamine was significantly impaired in old rats (% relaxation at 10(-5.5) M histamine: young rats 25.4+/-3.1%; old rats 14.1+/-1.9%, P < 0.01), an effect completely prevented by NO-1886 (old rats + NO-1886; 22.8+/-2.8%, P < 0.05 vs. old rats). In contrast, NO-1886 showed no effect on the endothelium-independent relaxation by sodium nitroprusside. These results indicate that NO-1886 improves impaired endothelium-dependent relaxation of rat aorta associated with aging, possibly by correcting lipid metabolism.

Aging↗

PubMed1998

cDNA cloning and expression of bovine UDP-N-acetylglucosamine: alpha1, 3-D-mannoside beta1,4-N-acetylglucosaminyltransferase IV.

UDP-N-acetylglucosamine:alpha1,3-D-mannoside beta1, 4-N-acetylglucosaminyltransferase (GnT-IV) is one of the essential enzymes in the production of tri- and tetra-antennary Asn-linked sugar chains. Recently, we have successfully purified GnT-IV from bovine small intestine. Based on the partial amino acid sequence of the purified bovine GnT-IV enzyme, its cDNA has been cloned from bovine small intestine. The open reading frame is 1,605 base pairs long, and this sequence produced GnT-IV activity on transient expression in COS-7 cells. Although the deduced amino acid sequence does not have any significant homology with other known N-acetylglucosaminyltransferases (GnTs), the hydrophobicity profile showed a typical type II transmembrane protein structure, which is common to many glycosyltransferases. N-terminal amino acid sequencing of the purified GnT-IV revealed that 92 amino acids, including a transmembrane region, were truncated during purification. Of the three potential N-glycosylation sites Asn-458 was actually glycosylated in the purified enzyme, although this N-glycosylation site could be abolished without any reduction in GnT-IV activity. Serial deletions at both the N and C termini proved that the catalytic domain of GnT-IV is located in the central region of the enzyme. The GnT-IV mRNA level correlated with enzymatic activity in the various bovine tissues tested.

Amino Acid Sequence↗

PubMed1998

In-vacuum figure-8 undulator for hard X-rays with both horizontal and vertical polarization.

A figure-8 undulator of the in-vacuum type has been adopted as an insertion device for BL24XU, the Hyogo Beamline at SPring-8, to provide hard X-rays with both horizontal and vertical polarization instead of a tandem undulator consisting of horizontal and vertical undulators. The undulator will be operated with the gap almost fixed at 11.6 mm to provide the fundamental radiation with horizontal polarization at 9.5 keV and the 1.5th harmonic with vertical polarization at 14 keV.

Journal Article↗

PubMed1998

An insertion device for the soft X-ray photochemistry beamline at SPring-8.

A figure-8 undulator is an insertion device (ID) proposed at SPring-8 to reduce the heat-load problems encountered with ordinary linear undulators. This device is useful when the K value is high in order to obtain low-energy photons as the fundamental of the undulator radiation. It has therefore been adopted as the ID for the soft X-ray photochemistry beamline (BL27SU) at SPring-8 because linearly polarized photons between 100 and 2000 eV are necessary for the experiments on this beamline. The figure-8 undulator for BL27SU is now under construction and, in the first phase of operation, is expected to cover the energy range down to 500 eV. In the second and third phases, the lowest energy may be reduced to 170 and 100 eV, respectively.

Journal Article↗

PubMed1998

Construction of a vertical undulator at SPring-8.

A new-type insertion device (ID) has been constructed for the structural-biology beamline (BL45XU) at SPring-8. The ID consists of two undulators which can provide vertical polarized radiation (vertical undulators). By changing the individual gap of each undulator independently, photons with two different energies can be obtained. Magnetic field measurements show that the maximum horizontal field is 0.49 T and the magnetic performance is as good as expected.

Journal Article↗

PubMed1998

SPring-8 in-vacuum undulator beam test at the ESRF.

Before the commissioning of SPring-8, the in-vacuum hybrid undulator developed at SPring-8 had been brought to the ESRF for the first beam test in the summer of 1996. The purpose of this test was to investigate the influence of the in-vacuum undulator on the beam and check its vacuum system. However, heating by the resistive wall impedance turned out to be a critical issue for the in-vacuum undulators.

Journal Article↗

PubMed1998

Spectroscopic Techniques using Synchrotron Radiation and Free-Electron and Conventional Lasers.

Considerable progress in the investigation of the electronic and vibrational properties of atoms, molecules, materials, surfaces and interfaces has been achieved by combining different photon sources of complementary characteristics. In this paper some experimental results obtained recently at LURE by using two synchronized sources, such as the IR free-electron laser (FEL) CLIO, the VUV storage ring FEL, synchrotron radiation and table lasers, are presented. Using CLIO synchronized with a YAG laser allows the investigation of the vibrational properties of adsorbed species by the non-linear optical technique of visible-IR sum (difference) frequency generation, as shown for the adsorption of hydrogen on platinum in the electrochemical environment. The second result reported here relates to the study of the intersubband stimulated emission in GaAs/GaAlAs quantum wells by pump-probe experiments using the two-colour configuration of CLIO. The combination of a mode-locked Ar(+) laser and synchrotron radiation has been used for investigations in a pump-probe arrangement of the ionization of Xe atoms via the resonant state Xe* 5p(5)5d [3/2](1). The final example is a time-resolved core-level spectroscopy study of photoexcited Si(111) 2 x 1 surfaces by using a combination of the naturally synchronized UV storage ring laser and synchrotron radiation.

Journal Article↗

PubMed1998

SPring-8 twin helical undulator.

There are several ways of producing circularly polarized light, such as using asymmetric devices, crossed undulators etc. The SPring-8 helical undulator introduces a simple way of producing both horizontal and vertical fields in one undulator. All the magnet arrays are arranged above and below the plane of the electron orbit, so there is no limitation of access from the sides of the undulator. For the SPring-8 BL25SU, two helical undulators will be installed in tandem, and the helicity of the polarization can be switched at up to 10 Hz using five kicker magnets.

Journal Article↗

PubMed1998

In-vacuum undulators of SPring-8.

Most of the SPring-8 insertion devices are in-vacuum undulators except for the soft X-ray devices and one elliptical wiggler. The standard-type SPring-8 in-vacuum undulator has a period of 32 mm and a minimum gap of 8 mm. The fundamental radiation energy ranges from 5.2 to 18.5 keV. Three standard in-vacuum undulators are already installed in the ring and are operating without any problems. The magnetic field correction, the vacuum system and the commissioning of the in-vacuum undulators are described in this paper.

Journal Article↗

PubMed1998

Absolute calibration of a soft X-ray spectrograph for X-ray laser research using white beam.

Absolute calibration of a soft X-ray spectrograph has been performed using a white beam of synchrotron radiation. The calibrated spectrograph was a flat-field grazing-incidence spectrograph with an X-ray CCD detector for X-ray laser research. Absolute sensitivity of the spectrograph system can be obtained from transmitted spectra using filters made of several different materials, each providing an absorption-edge wavelength standard. The absolute sensitivity determined in this work shows nearly the same behaviour with wavelength as that in another calibration experiment using a laser-produced plasma as an X-ray source.

Journal Article↗

PubMed1998

Development of an elliptical multipole wiggler at SPring-8.

An elliptical multipole wiggler (EMPW) based on a new concept has been installed on the SPring-8 storage ring. The EMPW, with a 120 mm period, has a critical energy of 50 keV at a gap of 20 mm. It will provide high-brilliance hard circularly polarized X-rays in the 100-300 keV range to the pilot beamline dedicated to materials science: the Compton scattering beamline. Field measurements, field integrals, the expected fluxes, polarization rates, power and power densities are presented for two operating gaps: 30 mm during commissioning, 20 mm later.

Journal Article↗

PubMed1998

Ionizing radiation activates c-Jun NH2-terminal kinase (JNK/SAPK) via a PKC-dependent pathway in human thyroid cells.

Thyroid gland is known to be higher sensitive to carcinogenic effects of external ionizing radiation (IR) than other tissues. To clarify the cell-specific response following irradiation, activations of c-Jun NH2-terminal kinases (JNKs), which is one of mitogen-activated protein kinases (MAPKs) family members, and extracellular signal-regulated kinase (ERK) were examined in primary cultured human thyroid cells in comparison with human diploid fibroblast cells, WI-38. Although UV exposure strikingly induced JNK activity in both cells, the dose-response increase following IR exposure was observed in thyroid cells with the maximal JNK activity (3.5 fold induction) obtained at 10 Gy exposure, but no increase in WI-38 cells. The JNK activity was reached a maximum of 2.2 fold induction at 30 min after 5 Gy exposure and then sustained for at least 12 hr. On the other hand, ERK activity was not stimulated in thyroid cells following irradiation. The effects of 12-O-tetradecanoylphorbol beta-acetate (TPA) mimicked those of radiation on JNK cascade and 1-(5-isoquinolinesulphonyl)-2,5-dimethylpiperazine 2HCl (H7) and pretreatment with TPA blocked JNK activation following irradiation. Our results demonstrate that IR stimulates JNK activity in cultured human thyroid cells but not in fibroblasts indicating distinct activation and regulation mechanisms of JNK cascade. The JNK activation following IR exposure is mediated at least partially through a PKC-dependent pathway.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed1998

Ataxia-telangiectasia without immunodeficiency: novel point mutations within and adjacent to the phosphatidylinositol 3-kinase-like domain.

Ataxia-telangiectasia (AT) is an autosomal recessive disorder characterized by progressive ataxia, telangiectasia, sinopulmonary infections, hypersensitivity to ionizing radiation, and combined immunodeficiency. Recently, the AT gene (ATM) was cloned and shown to be mutated in AT patients. In this report, mutation analysis of ATM was performed in a 24-year-old AT patient without immunodeficiency. ATM amplified with reverse transcriptase-polymerase chain reaction (RT-PCR) was screened with a ribonuclease (RNase) cleavage assay and auto-sequenced. This patient, a compound heterozygote, showed two mutations in ATM: one missense mutation leading to a Leu2656Pro substitution and the other to the truncation at codon 3047 (Arg-->ter). The latter mutation is within the phosphatidylinositol 3-kinase (PI 3-kinase)-like domain and the former is outside but close to the domain. The particular phenotype in our patient, no immunodeficiency, suggests incomplete functional loss of ATM protein. The clinical spectrum of AT caused by ATM mutations may be broader than previously thought. Further analysis of patients with similar phenotypes will make the relation between ATM genotype and phenotype clear.

Adult↗

PubMed1998

Detection of human herpesvirus 7 (HHV-7) DNA in breast milk by polymerase chain reaction and prevalence of HHV-7 antibody in breast-fed and bottle-fed children.

Twenty-nine breast milk mononuclear cell samples were analyzed for human herpesvirus 7 (HHV-7) DNA, human herpesvirus 6 (HHV-6) DNA, and human cytomegalovirus (HCMV) DNA by polymerase chain reaction (PCR). In addition, peripheral blood mononuclear cell samples from 13 puerperants were analyzed for HHV-7 DNA by PCR, and seropositivity of HHV-7 was also analyzed in breast-fed and bottle-fed children. HHV-7 DNA was detected in 3 of 29 breast milk samples. HCMV DNA was also detected in 3 of 29 breast milk samples, but HHV-6 DNA was not detected. HHV-7 DNA was detected in 11 of 13 samples of peripheral blood mononuclear cells. Though the seropositivity rate for HHV-7 in breast-fed children was slightly higher than that in bottle-fed children at 18 and 24 months old, the difference was not statistically significant. From these results, we speculate that breast-feeding may be one of the transmission routes of HHV-7, although this is not the main route.

Antibodies, Viral↗

PubMed1998

An evaluation of motor function in transverse colon transplants after total gastrectomy.

The motor activity of the isolated colon is understood less than that of any other part of the gastrointestinal viscus. Thus, the aim of the present study was to evaluate the motor activity of the interposed transverse colon following total gastrectomy through a study of 21 patients. Manometric studies were carried out with a 5-lumen, open-tipped catheter in the resting state, in response to dry swallows, and swallowing distilled water and a liquid meal. Contractile waves in the interposed colon grafts were divided into three types, namely, high-amplitude propagated contractions (HAPCs), low-amplitude propagated contractions (LAPCs), and low-amplitude nonpropagated contractions (LANPCs). No retrograde contractions were observed during the entire recording. Motor activity in the interposed colon increased to a greater extent after swallowing distilled water or liquid meals than during the resting period or after dry swallows; however, there was no significant difference between the effect of distilled water and liquid meals. The motor activity of the interposed colon was lower in patients with symptoms than in asymptomatic patients. These results suggest that the volume, rather than the composition, of the lumen contents is an important factor for inducing interposed colon graft contractions, and that contractions of the interposed colon can help to propel the contents of the colon into the duodenum and clear any duodenal juice if reflux should occur.

Anastomosis, Surgical↗

PubMed1998

Contractile and phosphatidylinositol responses of rat trachea to anticholinesterase drugs.

PURPOSE: Some anticholinesterases (anti-ChE) such as neostigmine and pyridostigmine but not edrophonium, stimulate phosphatidylinositol (PI) response. Although a direct relationship was suggested between the increase in PI response and airway smooth muscle contraction, there are no data regarding the effects of anti-ChE drugs on airway smooth muscle. Thus, we examined the contractile properties and PI responses produced by anti-ChE drugs. METHODS: Contractile response. Rat tracheal ring was suspended between two stainless hooks in Krebs-Henseleit (K-H) solution. (1) Carbachol (CCh), anti-ChE drugs (neostigmine, pyridostigmine, edrophonium) or DMPP (a selective ganglionic nicotinic agonist) were added to induce active contraction. (2) The effects of 4-diphenylacetoxy-N-methyl-piperidine methobromide (4-DAMP), an M3 muscarinic receptor antagonist, on neostigmine- or pyridostigmine-induced contraction of rat tracheal ring were examined. (3) Tetrodotoxin (TTX) was tested on the anti-ChE drugs-induced responses. PI response. The tracheal slices were incubated in K-H solution containing LiCl and 3[H]myo-inositol in the presence of neostigmine or pyridostigmine with or without 4-DAMP, an M3 muscarinic receptor antagonist. 3[H]inositol monophosphate (IP1) formed was counted with a liquid scintillation counter. RESULTS: Carbachol (0.1 microM), neostigmine (1 microM), pyridostigmine (10 microM) but not edrophonium or DMPP, caused tracheal ring contraction. 4-DAMP, but not tetrodotoxin, inhibited neostigmine and pyridostigmine-induced contraction. Neostigmine- or pyridostigmine-induced IP1, accumulation was inhibited by 4-DAMP. CONCLUSIONS: The data suggest that anti-ChE drugs activate the M3 receptors at the tracheal effector site.

Animals↗

PubMed1998

Equator ring efficacy in maintaining capsular bag integrity and transparency after cataract removal in monkey eyes.

BACKGROUND: The purpose of the study was to evaluate the efficacy of the equator ring in maintaining capsular bag integrity at the equator and transparency of the posterior capsule after cataract surgery. using cynomolgus monkeys. METHODS: After lens removal using an infusion-aspiration method, a flexible silicone ring with a groove on its inner surface was inserted in the bag through a window made by continuous circular capsulorhexis in six eyes. Of these, four monkey eyes underwent posterior chamber intraocular lens (IOL) implantation and two monkey eyes did not receive IOLs. Lensectomy without ring insertion was performed as a control in the six fellow eyes. Of these, four eyes received an IOL and two did not. The eyes were followed for an average of 5.9 +/- 1.1 months before enucleation. The effects were evaluated by stereo and light microscopy. RESULTS: The ring effectively maintained the circular contour of the capsular bag (ratio of the short and long axes, 0.97 +/- 0.01) and posterior capsule transparency (P = 0.017). CONCLUSIONS: This study demonstrated that the equator ring is a promising device for maintaining capsular bag integrity and minimizing posterior capsule opacification after cataract surgery.

Animals↗