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Biomedical subjects

K Ohta

Publications and source records attributed to K Ohta.

At least 847 records · Page 47Linked to original sources
PubMed1982

Relationship between colloid droplets of thyroid follicular cells and serum thyroglobulin concentration in neonatal rats after thyrotropin releasing hormone (TRH) injection.

Thyrotropin Releasing Hormone (TRH) shows the obvious and long-durated stimulation to the neonatal thyroid tissue through the pituitary. The sequential changes of serum thyroglobulin (Tg) levels and light and ultrastructural change in the cells of the thyroid gland were studied after TRH injection into neonatal rats. TRH injection induced a rapid increase of the colloid droplets in the thyroid follicular cells followed by a slow increase in serum Tg levels. Ultrastructurally, although marked surface activities consisting of formation of pseudopods and colloid droplets were observed after TRH injection, luminal colloid did not appear to go across the intercellular space between the thyroid follicular cells.

Animals↗
PubMed1982

The effect of alpha-melanocyte-stimulating hormone on the adrenal cortex of the fetal rat.

The effect of alpha-melanocyte-stimulating hormone (alpha-MSH) on the fetal adrenal cortex in rat was studied in vivo and in vitro. In vivo, an injection of alpha-MSH stimulated the adrenal cortex slightly. Treatment of the adrenal cortex with alpha-MSH in organ culture caused hyperfunctional change in the innermost layer of the cortex, the detection of which was done by electron microscope. This treatment caused at the same time an increase in corticosterone in the culture medium. Furthermore, comparison was made between alpha-MSH and ACTH with respect to their effect on the fetal adrenal cortex.

Adrenal Cortex↗
PubMed1981

Determination of glutamic acid and gamma-aminobutyric acid in Ringer's solution without desalination at the femtomole level by gas chromatography chemical ionization mass spectrometry.

For the quantification of glutamic acid in Ringer's solution, pentafluoropropionic methyl ester was the most sensitive derivative. The detectable concentration was 0.01 microM glutamic acid in Ringer's solution; the amount of the preparation was 1 pmol and the injection into a gas chromatograph mass spectrometer was 10 fmol. For the quantification of gamma-aminobutyric acid in Ringer's solution, the trifluoroacetal-hexafluoropropionyl ester was quantification of gamma-aminobutyric acid in Ringer's solution, the trifluoroacetal-hexafluoropropionyl ester was detectable at a concentration of 0.01 microM. Ringer's salts facilitated acylation in the order heptafluorobutyric anhydride greater than pentafluoropropionic anhydride greater than trifluoroacetic anhydride. The effect depended on esterification of carboxy groups in the order methyl ester greater than hexafluoropropionyl ester greater than butyl ester. Sodium carbonate, sodium acetate and sodium citrate also facilitated acylation with pentafluoroproionic anhydride, while sodium phosphate inhibited the acylation and sodium sulfate inhibited it slightly. The pentafluoropropionic methyl ester of glutamic acid was stable for up to 10 days, when it was dissolved in acetone and stored at -18 degrees C.

Gas Chromatography-Mass Spectrometry↗
PubMed1981

Studies in atopic asthma with emphasis on correlation among various tests and various antibodies.

The prick-test titration, allergen provocation test, acetylcholine inhalation test, total serum IgE measurement, histamine release test, and serum IgE, IgG, IgA, and IgM antibody determinations were carried out in atopic asthmatic patients who had never received immunotherapy with mite extract. Comparison of these procedures shows good correlation between them. Skin-test titration appears to be a fairly accurate and reliable method to determine causative allergens. The antigen inhalation provocation test tends to be positive among subjects with low thresholds to acetylcholine. This indicates that patients with airway tracts hyperreactive to acetylcholine are prone to asthma attacks even with exposure to small amounts of specific allergen and probably to various stimuli. Atopic subjects produce more IgE antibody and other antibodies than nonatopic subjects do. The quantity of specific antibodies to mite was lowest for IgM in atopic subjects.

Adolescent↗
PubMed1981

Human IgE antibody-forming cells. Radio-resistant and radio-sensitive subpopulations.

In vitro IgE and antimite IgE antibody (IgE Ab) synthesis was investigated. Peripheral blood lymphocytes (PBL) from atopic patients depleted of E-rosetting T cells developed IgE and IgE Ab in the absence of pokeweed mitogen (PWM), and it was not significantly affected by addition of T cells of of PWM. 1,000 R irradiation decreased more than 50% of the IgE and IgE Ab-producing capacity in 2 of 8 cases, but the remainder were not significantly affected. Increase of the gamma-ray dose from 1,000 to 12,000 R did not result in more suppression. Radio-resistant as well as radio-sensitive subpopulations may exist in the PBL of atopic patients. The radio-sensitive component of IgE and IgE Ab formation was suppressed by PWM, while the radio-resistant component was not affected.

Animals↗