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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 811 records · Page 45Linked to original sources
PubMed1988

Serotonin reduction in the mouse neostriatum during hyperthermia-induced convulsions studied by immunohistochemistry.

Changes occurring in serotonin neurons during hyperthermia-induced convulsions were examined by means of a modified immunohistochemical method. All mice (8-12 weeks of age) exposed to the temperature of 50 degrees C had convulsions, showing a generalized tonic and/or clonic pattern. Immediately after the convulsions, the animals were perfused transcardially with a fixative. A significant reduction in serotonin immunoreactivity was observed in the neostriatum (caudate-putamen complex) of the mice which had hyperthermia-induced seizures, while the serotonin immunoreactivity remained unchanged in the neocortex and paleostriatum. These results suggest that serotonin may be an important mediator in the mechanism of hyperthermia-induced convulsions or that the susceptibility of serotonin neurons to a convulsive state is greatest in the neostriatum.

Animals↗
PubMed1988

Transcellular ion currents and extension of Neurospora crassa hyphae.

Hyphae of Neurospora crassa, like many other tip-growing organisms, drive endogenous electric currents through themselves such that positive charges flow into the apical region and exit from the trunk. In order to identify the ions that carry the current, the complete growth medium was replaced by media lacking various constituents. Omission of K+ or of phosphate diminished the zone of inward current, effectively shifting the current pattern towards the apex. Omission of glucose markedly reduced both inward and outward currents; addition of sodium azide virtually abolished the flow of electric current. Growing hyphae also generate a longitudinal pH gradient: the medium surrounding the apex is slightly more alkaline than the bulk phase, while medium adjacent to the trunk turns acid. The results suggest that Neurospora hyphae generate a proton current; protons are expelled distally by the H+-ATPase and return into the apical region by a number of pathways, including the symport of protons with phosphate and potassium ions. Calcium influx may also contribute to the electric current that enters the apical region. There seems to be no simple obligatory linkage between the intensity of the transcellular electric current and the rate of hyphal extension. Calcium ions, however, are required in micromolar concentrations for extensions and morphogenesis of hyphal tips.

Calcium↗
PubMed1988

Assessment of L-ascorbic acid requirement for prolonged survival in ODS rats and their susceptibility to urinary bladder carcinogenesis by N-butyl-N-(4-hydroxybutyl)nitrosamine.

Assessment of L-ascorbic acid requirement for prolonged survival in ODS (genotype: od/od) rats and their susceptibility to urinary bladder carcinogenesis by N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) were examined. In ODS rats without L-ascorbic acid synthesizing ability, the 50 ppm dietary total ascorbic acid (TAA) was insufficient to survive for 4 weeks, the 250 ppm dietary TAA was sufficient to survive for 36 weeks. In examination of BBN treatment, ODS rats--although showing a lower availability of TAA than the heterozygotes (+/od) and normal (+/+) rats with L-ascorbic acid synthesizing ability--were equally susceptible to bladder carcinogenesis.

Animals↗
PubMed1988

Amygdaloid pathway to the trigeminal motor nucleus via the pontine reticular formation in the rat.

The connections of the amygdala with the trigeminal motor nucleus were studied by light and electron microscopy. Horseradish peroxidase (HRP) experiments showed that the pontine reticular formation, ventromedial to the spinal trigeminal nucleus at the level rostral to the genu of the facial nerve, receives fibers from the central nucleus of the amygdala ipsilaterally and sends fibers to the trigeminal motor nucleus contralaterally. Electron microscopic observations were carried out on the pontine reticular formation after electrolytic lesions in the central nucleus of the amygdala and HRP injections into the contralateral trigeminal motor nucleus were made on the same animal. These experiments using the combined degeneration and HRP technique clearly demonstrated that degenerating amygdaloid fibers made synaptic contacts with retrogradely labeled neurons.

Amygdala↗
PubMed1988

Amygdaloid projections to commissural interneurons for masticatory motoneurons.

Injections of wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) into the trigeminal motor nucleus resulted in retrograde labeling of neurons, called commissural interneurons for masticatory motoneurons, in the contralateral supratrigeminal region. Further HRP studies, in which WGA-HRP injections were made into the amygdala and supratrigeminal region, indicated that the supratrigeminal region receives fibers from the central nucleus of the amygdala ipsilaterally. These findings raised the possibility of direct connections between the amygdala and commissural interneurons. In order to confirm the connections, electrolytic lesions in the central nucleus of the amygdala and WGA-HRP injections into the contralateral trigeminal motor nucleus were made on the same animal and electron microscopic observation was carried out on the supratrigeminal region. Of particular interest was that degenerating amygdalotegmental fibers synapsed upon HRP-labeled neurons.

Amygdala↗
PubMed1988

Location on the evolutionary tree of influenza H3 haemagglutinin genes of Japanese strains isolated during 1985-6 season.

The nucleotide sequences of the haemagglutinin (HA) genes of influenza A (H3N2) isolates from the 1985-6 season in Japan along with those of several viruses isolated between 1982-5 from other countries were analyzed to determine the origin of the 1985-6 Japanese strains. The HA genes of these viruses consisted of 1762 nucleotides and had a three-nucleotide deletion downstream from the stop codon when compared to the sequences of earlier Hong Kong H3N2 viruses. An evolutionary tree of the HA genes of these viruses was drawn using the A/Bangkok/1/79 sequence as the starting point. Eight strains isolated from Asian and Pacific regions including Japan in the 1985-6 season (one in May) had the HA genes located closely on the evolutionary tree but away from those of the isolates in North America and Europe during the 1984-5 season, and a common ancestry for these viruses was suggested.

Amino Acid Sequence↗
PubMed1988

Identification of 5-hydroxytryptamine1A receptor proteins in bovine frontal cortex.

5-Hydroxytryptamine1A (5-HT1A) receptor proteins were identified by a novel approach in which photoaffinity labeling technique was used in conjunction with affinity column chromatography. 5-HT1A receptors were solubilized from bovine frontal cortical membranes with 0.3% digitonin and 0.1% Nonidet P-40, and bound effectively to 1-[2-(4-aminophenyl)ethyl]-4-(3-trifluoromethylphenyl)piperazine (PAPP)-coupled Affi-Gel 10 in a time-dependent manner. PAPP was shown previously to be a selective ligand for the 5-HT1A receptor. Two protein bands with molecular masses of approximately 55,000 and 38,000 daltons revealed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis were eluted from the affinity column with either 1 mM 5-HT or 1 microM [3H]1-[2-(4-azidophenyl)ethyl]-4-(3-trifluoromethyl-phenyl)piperazine ([3H]p-azido-PAPP). [3H]p-Azido-PAPP is a selective photoaffinity labeling probe for the 5-HT1A receptor. The intensity of these two protein bands and the incorporation of [3H]p-azido-PAPP into these two proteins decreased significantly when the solubilized fraction was preincubated with excess 5-HT or PAPP (saturating all 5-HT1A receptors) prior to affinity column chromatography. These results suggest strongly that these two proteins are related to the 5-HT1A receptor protein. The isoelectric points of the photolabeled 5-HT1A receptor proteins were 6.0 and 6.5.

Affinity Labels↗
PubMed1988

Allergic contact dermatitis due to hexamethylenetetramine in core molding.

Hexamethylenetetramine is an odorless powder and slowly liberates formaldehyde in an acid medium or when heated. It is usually used in the manufacture of formaldehyde resins, rubber and the explosive, cyclonite. It is also used as a hardener in core molding processes. It was reported as one of the formaldehyde releasers and as a cause of formaldehyde contact dermatitis. We report an allergic contact dermatitis due to hexamethylenetetramine, with a positive patch test reaction to hexamethylenetetramine (1% pet.) but not to formaldehyde (2% aq.). We concluded that this case was an allergic contact dermatitis from hexamethylenetetramine itself.

Chromatography, Gas↗
PubMed1988

Immunohistochemical analysis of cells in mucosal lesions of oral lichen planus.

We immunohistochemically analyzed the immunological background of the pathogenesis of oral lichen planus (OLP). Abundant lymphocytes infiltrated OLP mucosal lesions, particularly in satellite cell necrosis (SCN) regions, and cytotoxic/suppressor T lymphocytes were predominant in seven of 10 OLP cases. Some carried IL-2 receptors, particularly in SCN. Keratinocytes of the mucosal lesions expressed both HLA-ABC and HLA-DR antigens. This suggests that activated cytotoxic/suppressor T lymphocytes may play a major role in cytotoxicity to keratinocytes as effector cells in OLP. OKM1-, OKM5+, HLA-DR+ and IL-1+ cells, vascular endothelial cells and clusters of spindle-shaped or oval cells, which had the same surface characteristics as a monocyte macrophage subset, were abundant and, together with migrating lymphocytes, might play a role in the immune response in mucosal lesions of OLP.

Adult↗
PubMed1988

Low fidelity of cell-free DNA synthesis by reverse transcriptase of human immunodeficiency virus.

The fidelity of DNA synthesis by reverse transcriptases from human immunodeficiency virus and other retroviruses was compared by measuring the rates of misincorporation of dCMP in the place of TMP in cell-free DNA synthesis with polyadenylic acid as the template. The fidelity of human immunodeficiency virus reverse transcriptase was found to be about one-third of that of the reverse transcriptases of other retroviruses.

Autoradiography↗
PubMed1988

Three Japanese families with members carrying C7 silent allele (C7*Q0). Possibility for an association between C7*Q0 and C6*B.

Three Japanese families with members carrying C7 silent allele(s) (C7*Q0) are presented. C6 types in the family members were also examined, and it was found that C7*Q0 was transmitted from a parent to offsprings as a haplotype, C7*Q0-C6*B. In another study of C6 types in sera from 3 volunteer blood donors with homozygous C7 deficiencies, the C6 phenotypes were found to be C6 B (homozygote). It seems remarkable that C7*Q0 can be associated with C6*B.

Alleles↗
PubMed1988

3,5,3'-triiodo-L-thyronine binding sites in nuclei of human trophoblastic cells.

Nuclear binding sites of T3 in human trophoblastic cells were biochemically characterized. Nuclei were isolated by a combination procedure with mild homogenization of the freshly obtained trophoblastic tissue aged term gestation, centrifugations and Triton X-100 treatment. The isolated nuclei were incubated with various concentrations of 125I-T3 at 20 degrees C for 3 h. The total number of T3 binding sites per nucleus was approximately 650. The apparent association constant (Ka) was 6.0 X 10(9)M-1. Nuclear proteins extracted from purified nuclei with 0.4M KCl were able to bind T3 giving rise to nuclear thyroid hormone binding protein-T3 complexes and they were precipitated with bovine IgG, as a carrier protein, by 12.5% polyethylene glycol. Binding was maximum in 3 h incubation at 20 degrees C or in 18 h at 0 degrees C, while it dropped quickly at 37 degrees C. The binding characteristics were analyzed by Scatchard plots. In nuclear proteins obtained from 8 term placentae there was a single set of high affinity-low capacity T3 binding sites with Ka of 7.0 X 10(9)M-1. The capacity is about 62.7 fmol T3/mg DNA. The binding sites were found to be specific for L-T3, while L-T4 was about 100-fold less effective, rT3 ineffective, and D-T3 and D-T4 were roughly 1/8 and 1/5 as active as L-T3 and L-T4, respectively in displacing 125I-T3 from the binding sites. These data confirmed that human placenta is a target organ of thyroid hormones; trophoblastic cells contain T3 nuclear receptors which are biochemically similar to those isolated from liver, although the capacity is low.

Cell Nucleus↗