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Biomedical subjects

F Kinoshita

Publications and source records attributed to F Kinoshita.

At least 73 records · Page 4Linked to original sources
PubMed1983

Evidence for noradrenergic involvement in naloxone-induced stimulation of luteinizing hormone release in prepubertal female rats.

The effects of phenoxybenzamine an alpha-adrenergic blocker, propranolol a beta-adrenergic blocker, and diethyldithiocarbamate a noradrenaline synthesis inhibitor, on the LH increase induced by naloxone an opiate antagonist, was investigated in 25 day old female rats. Pretreatment with phenoxybenzamine or diethyldithiocarbamate suppressed the LH increase induced by naloxone, whereas pretreatment with propranolol had no significant effects on the naloxone-induced LH release. These results suggest that naloxone-induced increase in LH release is mediated via a noradrenergic mechanism.

Animals↗
PubMed1983

An inter- and intralaboratory quality-control survey of radioimmunoassay of insulin, thyroxin, thyrotropin, cortisol, digoxin, gastrin, beta 2-microglobulin, and IgE in Japan with commercially available kits.

We report results of a quality-control survey of radioimmunoassay (RIA) of eight analytes, participated in by 249 laboratories of various types throughout Japan. For the purpose of the external control survey, lyophilized specimens containing two different concentrations of each analyte were sent to the participating laboratories, which supplied both their assay values and their raw data for the standard curves and for the samples. The individual data for the standard curve were analyzed by the RIA data-processing program described by Faden and Rodbard. The precision profile obtained for the individual assay was used as the estimate of the quality of each assay. Although there was a wide scatter in assay values, the quality of the assay by the individual laboratories was not the major contributor to this scattering, because the values they reported for the assays and precision profiles of the standard curves were almost identical with those obtained from the kit manufacturers. When the reported assay values were analyzed according to the brand of kits, by analysis of variance, the treatment mean square due to difference in the make of the kits significantly exceeded the error mean square due to "within-kit" variation in the assay of insulin, thyroxin, thyrotropin, cortisol, gastrin, and digoxin. The CVs for "between-kit," "within-kit," "between-assay" and "within-assay" variations (the latter two aspects were studied in a representative laboratory, for convenience of comparison) were about 20, 15, 13, and 7%, respectively. Because the observed within-kit variation is of almost the same magnitude as that expected from the combination of within-assay and between-assay variation, the skill of the users probably was equal and the accuracy and precision of the kits probably had the greatest impact on assay variation. This survey also emphasizes the criteria for commercially available RIA kits.

Analysis of Variance↗
PubMed1983

[Quantitative study of single photon radionuclide computed tomography--delineation of body contours].

Several methods to obtain the body contour which is necessary to reconstruct the quantitative images with single photon radionuclide computed tomography (SPRCT) are described in this paper. A multipurpose gamma camera system which is composed of 2 detectors, data processor and others were used to collect the data of SPRCT and body contour. An iterative reconstruction technique was implemented to reconstruct the image. Three methods for obtaining the body contour were tested. The first method utilizes X-ray CT data. The data which are obtained by GE CT/T are transferred to the data processor of SPRCT through the off-line magnetic tape and delineate the body contour. The second method uses a transmission source which was attached on the opposite side to detector. The third method uses gamma-rays which are generated by Compton scatter in the tissue of patient. The first and the second methods were able to use to obtain the body contour, but the contour obtained by third method was not accurate.

Gamma Rays↗
PubMed1982

Suppressive effect of dynorphin-(1-13) on luteinizing hormone release in conscious castrated rats.

The effect of intraventricular administration of dynorphin-(1-13) on luteinizing hormone (LH) release was studied in castrated conscious rats. The administration of 5 micrograms of dynorphin-(1-13) into the lateral ventricle inhibited LH secretion. Intravenous administration of naloxone blocked this suppressive effect of dynorphin on LH release. These results suggest a possible role of dynorphin, in addition to beta-endorphin and Met5-enkephalin, in the control of LH release in male rats.

Animals↗
PubMed1982

Suppressive effect of prostaglandin (PG)D2 on pulsatile luteinizing hormone release in conscious castrated rats.

The effect of intraventricular administration of prostaglandin (PG)D2 on pulsatile LH release was studied in castrated conscious rats. The administration of 5 micrograms of PGD2 into the lateral ventricle inhibited pulsatile discharge of LH secretion, in contrast to the stimulatory effect of PGE2. Intraventricular administration of 13,14-dihydro-15-keto-PGD2, a metabolite of PGD2, had no significant effect. Intravenous administration of 100 micrograms of PGD2 caused only a slight decrease in LH secretion. Intravenous administration of naloxone, a specific opiate antagonist, blocked the suppressive effect of PGD2 on Lh release. These results suggest that PGD2 plays an inhibitory role in pulsatile LH secretion in castrated male rats and that opiate receptors are involved in the PGD2-induced inhibition of LH secretion.

Animals↗
PubMed1982

Characterization of gamma-melanotropin-like immunoreactivity and its secretion in an adrenocorticotropin-producing mouse pituitary tumor cell line.

gamma MSH, a putative hormone in the N-terminal region of the ACTH/beta-endorphin (beta-EP) precursor protein, was studied by RIA with an antiserum against gamma 3MSH in ACTH-producing mouse pituitary tumor cells, AtT-20/D16v. Serial dilution of the culture medium or the cell extract gave parallel lines to the standard curve in the RIA for gamma MSH. Rat median eminence extracts enhanced the release of gamma MSH-like immunoreactivity (gamma MSH-LI) concomitant with ACTH-like immunoreactivity (ACTH-LI) and beta-EP-like immunoreactivity (beta-EP-LI). Dexamethasone suppressed the release of gamma MSH-LI as well as ACTH-LI and beta-EP-LI. Gel exclusion chromatography of the culture medium and the cell extract has revealed that gamma MSH-LI consists of two peaks; one eluted near the elution position of beta-lipotropin and the other near the elution position of beta-EP. There was no peak corresponding to the elution position of synthetic gamma 3MSH. However, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) has demonstrated that gamma MSH-LI migrated at five positions with molecular weights of 31K, 21-23K, 16-17K, 13-14K, and 3.8K, respectively. The 31K gamma MSH coincided with the migration position of 31K ACTH of 31K beta-EP, and 21-23K gamma MSH coincided with the position of 21-23K ACTH on SDS-PAGE. The 16-17K gamma MSH coincided with the mouse 16K fragment (reported by Eipper and Mains) of ACTH-beta-lipotropin precursor protein in the migration in SDS-PAGE and in immunoreactivity to anti-gamma MSH antiserum. [3H]Glucosamine was incorporated into 16K, 13K, and 3.8K gamma MSH. These results suggest that AtT-20/D16v cells produce gamma MSH-LIs with molecular weights of 31K, 21-23K, 16-17K, 13-14K, and 3.8K, and they are secreted concomitantly with ACTH-LI and beta-EP-LI.

Adrenocorticotropic Hormone↗
PubMed1982

[Clinical evaluation of transaxial bone imaging with 99mTc-phosphate compounds].

Single photon emission computed tomography using newly designed whole body imaging system which was composed of opposing dual gamma cameras, a rotating gantry and a sliding table was clinically evaluated for bone imaging. Two hundred and seventeen portions of various bone diseases were performed single photon emission computed tomography following conventional bone imaging with 99mTc-MDP (methylen diphosphonate) or -HMDP (hydroxymethylene diphosphonate) and the results were discussed. Transaxial images were sometimes superior than conventional images in the diagnosis of the tumor localization and extension of the facial bone. Combination of emission computed tomography to conventional methods also presented more exact informations for the diagnosis of the vertebral change. Separation of the overlapped radioactivities of the bone and the soft tissue is another advantage of the tomographic image, and cross-sectional images with enoughly high qualities were available in early time after administration of 99mTc-phosphate compounds. Useful diagnostic informations could be obtained by tomographic bone imaging combined with conventional imagings.

Adult↗