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Biomedical subjects

T Ando

Publications and source records attributed to T Ando.

At least 361 records · Page 20Linked to original sources
PubMed1994

Asbestos fibers and interferon-gamma up-regulate nitric oxide production in rat alveolar macrophages.

The present study was undertaken to determine whether asbestos exposure induces the formation of nitric oxide (NO.) radical by rat alveolar macrophages (AM). For this purpose, AM from Sprague-Dawley rats were cultured for 48 h in the presence or absence of either chrysotile (serpentine) or crocidolite (amphibole) asbestos fibers. The effects of asbestos fibers were compared with those of nonfibrogenic carbonyl iron particles. Nitrite (NO2-), the stable oxidation product of NO. in macrophage conditioned medium, was assayed by the Griess reaction. Production of NO2- by AM was significantly increased by both chrysotile (P < 0.01) and crocidolite (P < 0.05) asbestos fibers (10 micrograms/ml). Since interferon-gamma (IFN-gamma) is known to induce NO. synthase within macrophages, and since elevated levels of intrapulmonary IFN-gamma have been noted in asbestos workers, the combined effects of asbestos and IFN-gamma also were studied in the context of NO. formation. Addition of IFN-gamma (250 to 500 IU/ml) synergistically enhanced the formation of NO2- induced by chrysotile and crocidolite. Notably, carbonyl iron had no significant effect on NO. production by AM. NO2- production was significantly attenuated by the NO. synthase inhibitor, NG-monomethyl-L-arginine (0.5 to 1 mg/ml). By contrast, superoxide dismutase (150 U/ml) significantly enhanced asbestos-induced NO2- production by AM (P < 0.001). Since superoxide anion can interact with NO. to generate the toxic hydroxyl radical, and since superoxide dismutase is known to protect against asbestos-induced injury, the induction of NO. radical by asbestos fibers may represent a novel form of asbestos-related injury.

Amino Acid Oxidoreductases↗
PubMed1994

[Effect of Oren-gedoku-to on changes in hexobarbital-induced sleeping time in chlorpromazine-treated mice].

The effects of Oren-gedoku-to on the hypnotic duration induced by hexobarbital, and on the change of this duration in chlorpromazine-treated mice were investigated. Single dose of Oren-gedoku-to (1.0 or 2.0 g/kg, p.o.) or chlorpromazine (10 mg/kg, p.o.) prolonged the hexobarbital hypnosis time. And the simultaneous dose of chlorpromazine (6.0 mg/kg, p.o.) and Orengedoku-to (1.0 g/kg, p.o.) indicated the equal effect for the administration of chlorpromazine (10.0 mg/kg, p.o.) alone. Although the mechanism of the action remains to be unknown, administration of Oren-gedoku-to in combination with chlorpromazine seems to be useful from the standpoint of alleviation of the side-effects caused by less dose.

Animals↗
PubMed1994

[A procedure for recording electroretinogram (ERG) with a contact lens-type electrode, and effect of sodium iodate on ERG in rats].

A procedure for recording the electroretinogram (ERG) in rats with a contact lens-type electrode was developed in order to examine visual toxicity overtime. Rats received a single intravenous injection of sodium iodate (SI), a retinotoxic compound, via the tail vein at a dose of 12.5, 20, 25 or 50 mg/kg, and the ERG was recorded for 10 days after dosing. Histopathologic examination of the retinas was then conducted. 1. The rats were anesthetized with ketamine hydrochloride (50 mg/kg, i.m.) after 90 to 120 min of dark-adaptation. Thirty-two responses to repetitive 1.2 joule light stimuli at 0.5 Hz interstimulus intervals were averaged by a microcomputer. Under these conditions, stable ERG a-wave, b-wave and oscillatory potentials could be recorded for 10 days. 2. At 12.5 mg/kg of SI, no treatment-related abnormalities were observed on the ERG. Doses of 20 mg/kg or more of SI caused depression of the amplitudes of the ERG a-wave and oscillatory potentials 2 hrs or 1 day after dosing. Following these changes, the amplitude of the ERG b-wave decreased 1 or 2 days after dosing. 3. Upon histopathologic examination of the retina, folding of the outer nuclear layer, disarrangement of the rods and cones and swelling and decrease of the pigment epithelial cells were observed at 20 mg/kg or more. The severity of the retinal lesions correlated well with the changes in the ERG. 4. Using this recording technique, it was confirmed that a stable ERG could be recorded repeatedly in rats, and the effects of SI on the ERG could be detected. Furthermore, histopathologic examination revealed that the severity of the retinal lesions correlated well with the changes in the ERG. These results indicate that the ERG recording technique employed in this study is useful for evaluating retinal toxicity in rats.

Animals↗
PubMed1994

[Double crush syndrome in patients with cervical spondylosis or ossification of posterior longitudinal ligament--a clinicophysiological study].

To clarify the clinical characteristics of double crush syndrome (DCS), we evaluated 207 patients with cervical spondylosis (CS) and 19 with ossification of posterior longitudinal ligament of the cervical spine (OPLL) clinicophysiologically. A diagnosis of DCS was based on the following criteria; 1) radiological evidence of CS or OPLL on X-ray films; 2) definite spinal cord compression on cervical magnetic resonance imaging (MRI); 3) neurological deficits in the upper extremities resulting from CS or OPLL; and 4) clinical and/or electrophysiological evidence of entrapment neuropathies in the upper extremities, namely carpal tunnel syndrome (CaTS), Guyon's tunnel syndrome (GTS), and/or cubital tunnel syndrome (CuTS). Pressure-provocative tests were used to confirm clinical entrapment neuropathies. Nerve conduction velocities were also examined. We found 28 patients with DCS (23 CS, 5 OPLL; 12.8% of all patients). There were 9 patients with clinical and electrophysiological DCS, 5 with clinical DCS, and 14 with electrophysiological DCS. Of the total number of patients with DCS, 21 proved to have CaTS, 4 had CuTS, 1 had GTS, 1 had both CaTS and CuTS, and 1 had both CaTS and GTS. Definite spinal cord compression was seen at C5/6 (23 patients), C4/5 (21), C3/4 (13) and C6/7 (10) on cervical MRI. In the majority of patients, neurological deficits of the upper extremities did not result from a single peripheral nerve lesion. It is well known that a discrepancy between neurological manifestation and neuro-imaging sometimes occurs in CS and OPLL, and circulatory disturbance in the spinal cord has been considered a possible pathogenetic mechanism of the disorder.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Antigenic relationship between the house dust mite Dermatophagoides farinae and the predacious mite Phytoseiulus persimilis.

We have examined the antigenic relationship between the house dust mite Dermatophagoides farinae and the predacious mite Phytoseiulus persimilis. Immunoblotting analysis demonstrated that there was a very weak antigenic cross-reactivity between these different suborder of mites but that this cross-reactivity was not attributed to D. farinaes major allergen's, Der fI and Der fII. These results suggest that P. persimilis might scarcely provoke allergic symptoms in patients sensitized to house dust mites.

Animals↗
PubMed1993

Alpha (1,3/1,4)fucosyltransferase (FucT-III) gene is inactivated by a single amino acid substitution in Lewis histo-blood type negative individuals.

Human alpha (1,3/1,4)fucosyltransferase (FucT-III) genes were cloned from genomic DNAs of seven Lewis negative (Le(a- b-)) individuals. Restriction mapping analyses revealed that an additional Pvu II site was created in the FucT-III genes from Lewis negative individuals. Four of these individuals were shown to be heterozygous for the Pvu II site and three were homozygous for it. The Pvu II site was produced by a single base substitution at the 508 nucleotide of coding sequence, G to A, resulting in the amino acid substitution, Gly to Ser at position 170. Another single base substitution, resulting in the change of Asp to Ala at position 336, was observed in the Lewis negative FucT-III gene which did not have the Pvu II site. The FucT-III enzyme was inactivated by these two mutations resulting in a single amino acid substitution in the catalytic region. All FucT-III genes, regardless of the Pvu II site, from Lewis negative individuals had a single base substitution, the T at position 59 to G, resulting in the change of Leu to Arg at position 20. This mutation, however, was not responsible for FucT-III gene inactivation.

Amino Acid Sequence↗
PubMed1993

Human alpha-1,3 fucosyltransferase (FucT-VI) gene is located at only 13 kb 3' to the Lewis type fucosyltransferase (FucT-III) gene on chromosome 19.

Human alpha-(1.3/1,4) fucosyltransferase (FucT-III) gene and alpha 1,3 fucosyltransferase (FucT-VI) gene were found in the 38-kb fragment isolated from a human cosmid library. These genes were present 13 kb apart in tandem orientation. The FucT-III gene has already been mapped on the Lewis locus of chromosome 19. This demonstrated that FucT-VI gene was localized close to the Lewis locus on chromosome 19.

Base Sequence↗
PubMed1993

Early appearance and activation of natural killer cells in tumor-infiltrating lymphoid cells during tumor development.

We investigated NK cell infiltration into tumor developing lesions at early stage of tumor development after intraperitoneal inoculation of 3LL lung carcinoma into syngeneic C57BL/6 mice. Natural killer (NK) cells, which were detected by anti-NK 1.1 monoclonal antibody (mAb), remarkably increased in number in tumor-developing lesions (peritoneal cavity) as early as day 3 after inoculation of 3LL. The tumor-infiltrating NK cells from 3LL-inoculated mice produced a high level of interferon-gamma by co-culture with 3LL and showed enhanced cytotoxic activities against both NK-sensitive (YAC-1) and NK-resistant (3LL and P815) tumors. Furthermore, mice depleted of NK cells by injection of anti-NK 1.1 mAb or anti-asialo GM1 antibody showed shorter survival times after intraperitoneal inoculation of 3LL when compared with control mice. These results suggest that NK cells infiltrate the tumor-developing lesion at an early stage and may participate in the early protection against tumors through production of a high amount of interferon-gamma and enhanced cytotoxicity at tumor-bearing sites.

Animals↗
PubMed1993

Electrostatic potential around actin.

We presume that tension of contracting muscle originates from electrostatic force experienced by actin and myosin. We suppose that a high-energy state of myosin-ADP-Pi interacts with actin, transferring the stored energy to actin, and that the actin excited in this way develops around itself electric field which exerts sliding force against charged myosin heads. To explore the idea, first we conjectured how electric charges on actin produce electric field in the axial direction, and second we experimentally examined electrostatic circumstances around actin in solution and in muscle fibers by optimizing diffusion-enhanced fluorescence energy transfer. In the experiments, Tb ion, which has a long excited-state lifetime, was used as donor. To introduce Tb to actin, Tb-DTPA-phalloin and Tb-DTPA-maleimide were synthesized. As acceptors with electric charges (Za = -3 to +2), rhodamine B that was conjugated with various amino acids or their derivatives was used. The fluorescence energy transfer efficiency (ET) was estimated from the shortening in the lifetime of Tb. The electrostatic circumstances around actin were inferred from the ET-Za relation. When Tb was introduced at Cys-374 of actin, the Tb-site was found in negative electric potential. S-1 binding to the labeled actin neutralized the electric potential almost completely. Tb-DTPA-phalloin bound to actin seemed to reside in the vicinity of tryptophan residue(s). Electric potential around the phalloin site was negative. S-1 binding to the actin slightly reduced the negativity. In glycerinated fibers in the rigor state, the phalloin site was again found in negative potential. When fibers were transferred from an ADP-rigor solution to an active solution, the negative electric potential was neutralized to some extent. The direction of this change could not be explained by detachment of crossbridges from actin, since the detachment should have given an opposite direction of changes in the electric potential. Thus, this observation may indicate that electric potential characteristic of the active state occurs at actin surfaces.

Actins↗
PubMed1993

Effect of toremifene on the growth, hormone receptors and insulin-like growth factor-1 of hormone-dependent MCF-7 tumors in athymic mice.

Toremifene given in different sizes of silastic capsules was used to treat MCF-7 tumors in athymic mice. Toremifene inhibited the estradiol-stimulated growth of MCF-7 tumors in athymic mice. Average serum concentrations of toremifene obtained using a sustained-release preparation of the drug (in 0.5-, 1.0-, and 2.0-cm silastic capsules) increased gradually in a capsule-size-dependent fashion. Much higher levels of toremifene or N-demethyl-toremifene were detected in tumors (target tissues of estrogen) as compared with muscles (non-target tissues of estrogen). The concentration of toremifene in serum (i.e., 10-30 ng ml-1) was sufficient to inhibit the estrogen-stimulated growth of MCF-7 tumors at physiological (i.e., 200-400 pg ml-1) serum estradiol concentrations in premenopausal women. No significant difference in estrogen receptor (ER) levels was found between the estradiol-alone group and the toremifene-treated groups. However, the ER levels in the toremifene-alone group and the no-treatment group (no toremifene or estradiol) tended to increase as compared with the estradiol-alone group. Toremifene blocked the estradiol-induced increase in progesterone receptor levels in a dose-dependent fashion. Insulin-like growth factor-1 (IGF-1) levels in the MCF-7 tumors significantly decreased in the toremifene-alone group as compared with the estradiol-alone group. These results show the antiestrogenic action of toremifene on hormone-dependent MCF-7 tumors in athymic mice.

Animals↗