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Biomedical subjects

N Kubo

Publications and source records attributed to N Kubo.

At least 163 records · Page 9Linked to original sources
PubMed1987

Neurotensin receptors on the rat liver plasma membranes.

Neurotensin (NT) is now classified as a brain-gut peptide in the central nervous system and gastrointestinal tract. In the present study, we characterized the NT receptors on the rat liver plasma membranes. The specific binding of [3H]NT was time dependent, reversible, and saturable. Scatchard analysis of the specific binding data yielded two classes of binding sites, a high affinity site and a low affinity site. The average maximum number of binding sites (Bmax) amounted to 13.3 +/- 1.1 fmol/mg protein at high affinity site and 122.3 +/- 21.5 fmol/mg protein at low affinity site, respectively. The dissociation constant (Kd) had values of 0.39 +/- 0.01 nM at high affinity site and 8.1 +/- 1.1 nM at low affinity site, respectively. The amount of specifically bound [3H]NT was significantly reduced in the presence of mono and divalent cations, EDTA, EGTA and a peptidase inhibitor bacitracin, NT1-13 competed with [3H]NT for its binding site with an IC50 of 0.19 nM at high affinity site (0.2 nM concentration of [3H]NT) and 0.7 nM at low affinity site (4.0 nM concentration of [3H]NT). Xenopsin, a NT analogue separated from the skin of Xenopus laevis, was equipotent (IC50 0.75 nM) with NT1-13 at 4.0 nM concentration of [3H]NT. C-terminal sequence of NT contains the structure necessary for interaction with NT binding sites whereas N-terminal sequence had no binding activity. Since NT has a hyperglysemic and a hypercholesterolemic effects in rats, these NT receptors on the rat liver plasma membranes may be involved in the hyperglycemia and/or hypercholesteroremia induced by NT.

Amino Acid Sequence↗
PubMed1987

Antimuscarinic effects of antihistamines: quantitative evaluation by receptor-binding assay.

Quantitative evaluation of antimuscarinic effects of antihistamines (H1- and H2-receptor antagonists) was carried out using a receptor-binding assay. The -inhibition constants (Ki values) of twenty seven H1-receptor antagonists, one related antidepressant and three H2-receptor antagonists at H1-receptors and muscarinic receptors in the bovine cerebral cortex were determined. All the H2-receptor antagonists examined showed very low affinity for the muscarinic receptors. On the other hand, some H1-receptor antagonists (mequitazine, cyproheptazine, clemastine, diphenylpyraline, promethazine, homochlorcyclizine and alimemazine) had high affinity for the muscarinic receptors (Ki = 5.0-38 nM). Another group of H1-receptor antagonists (mepyramine, terfenadine, metapyrilen, azelastine, hydroxyzine and meclizine) had low affinity for the muscarinic receptors (Ki = 3,600-30,000 nM). Thus, a broad range of antimuscarinic potencies among the antihistamines was demonstrated. These results should provide helpful information with regard to the clinical and experimental use of antihistamines.

Animals↗
PubMed1986

[A study of regional cerebral blood flow before and after superficial temporal artery-to-middle cerebral artery anastomosis].

Regional cerebral blood flow (rCBF), using a single photon emission CT with Xe-133 inhalation method, was measured before and after the operation in 30 patients who underwent a superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. The purpose of this study is to assess the effect of STA-MCA anastomosis from the standpoint of hemodynamics and the results obtained were as follows: rCBF at rest increased after the operation, which was approximately 10% alterations and was localized in temporal region of operated hemisphere and frontal region of non-operated hemisphere respectively. rCBF during STA compression test after surgery decreased only in temporal region (anastomotic site) of operated hemisphere. This findings might indicate that blood flow via the bypass artery become to provide mainly to the confined area. CO2 reactivity was disturbed in 6 patients before operation, but it restored in 4 patients after operation. Autoregulation was also abolished in 8 patients before operation, but it restored in 6 patients after operation. In the group of severe degree of ischemia, however, autoregulation did not show the tendency to recover after the operation, whereas CO2 reactivity somewhat recovered. Angiographical retrograde filling which indicates collateral circulation reduced or disappeared in 12 out of 14 patients, in which postoperative rCBF in temporal region increased, in addition autoregulation and CO2 reactivity tended to recover after the bypass operation. These data mentioned above probably indicated the influences of CBF increase via the bypass artery. In summary, it might be concluded that the hemodynamic change such as disappearance of collateral circulation seen on angiography, additionally postoperative rCBF increase in anastomotic site seemed to be related to the restoration of these vascular responses such as CO2 reactivity and autoregulation in ischemic brain.

Adolescent↗
PubMed1986

[Choriocarcinoma of the stomach].

A 55-year-old Japanese man was admitted to our hospital in January 1985 complaining of epigastralgia. Radiologic and endoscopic examinations showed gastric carcinoma, but biopsy specimens taken by surgery showed the histologic pattern of choriocarcinoma. On autopsy, multiple metastatic sites wer observed, and histological examination of the primary and metastatic sites revealed choriocarcinoma. Primary gastric choriocarcinoma may develop from gastric cancer by retrodifferentiation.

Biopsy↗
PubMed1985

Molecular size of histamine H-1 receptor determined by target size analysis.

Target size analysis (radiation inactivation) was used to study the molecular size of the histamine H-1 receptor of bovine and human cerebral cortex in the intact membrane-bound state. The H-1 receptor in bovine and human cerebral cortex was found to exist in the membrane as a homogeneous population of the same size (160,000 daltons) in each case. Thus no evidence for the existence of multiple forms of the receptor has been found.

Animals↗