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Biomedical subjects

T Hirabayashi

Publications and source records attributed to T Hirabayashi.

At least 91 records · Page 5Linked to original sources
PubMed1989

Accumulation of tropomyosin in developing chicken gizzard smooth muscle.

Smooth muscle of chicken embryonic gizzards has been shown to contain 9 tropomyosin isoforms (E1, E2, E3, E4, E5, E6, E7, E8, and E9) in addition to alpha and beta isoforms (Hosoya et al. (1989) J. Biochem. 105, 712-717). At the early stages of development, the amount of these isoforms was larger than those of alpha and beta isoforms. However, they gradually decreased at later stages and finally disappeared completely after hatching. By using two-dimensional gel electrophoresis and an image analyzing system, we examined the process of tropomyosin accumulation in gizzard smooth muscle development. The accumulation patterns of tropomyosin isoforms and their relative molar ratios to actin in embryonic development were different from those in the stages after hatching. The relative molar ratio of tropomyosin to actin in the thin filament preparation of embryonic gizzards was lower than that of adult, and it gradually increased in the course of embryonic development.

Actins↗
PubMed1989

Calcitonin gene-related peptide-binding sites of porcine cardiac muscles and coronary arteries: solubilization and characterization.

Calcitonin gene-related peptide (CGRP)-binding sites were solubilized, using digitonin, from the porcine spinal cord, atria, and coronary arteries. The specific binding of 125I-human alpha-CGRP to the solubilized binding sites was inhibited by human alpha- and beta-CGRP and by rat alpha-CGRP, but not by angiotensin II or human calcitonin. Scatchard plot analysis of saturation gave the same KD value for CGRP in the crude membrane fractions of the tissues examined. The affinity of CGRP to the binding sites was decreased by solubilization in the atria and coronary arteries, but not in the spinal cord. Affinity labeling followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed distinct molecular sizes of the specific binding sites among the tissues; 70K for the spinal cord, 70K and 90K for the coronary arteries, and 70K and 120K for the atria. These results indicate that the molecular characteristics of the specific binding sites of CGRP in the cardiovascular system are distinct from those in the central nervous system.

Animals↗
PubMed1989

[Assay of erythropoietin in plasma by enzyme-linked immunosorbent assay].

Using an enzyme linked immunosolvent assay kit supplied by Toyobo Co., erythropoietin (EPO) concentration in plasma was measured. Normal 100 samples showed a logarithmic distribution in EPO concentrations and normal range was between 5.4-32.5 mU/ml (mean +/- 2 SD). Coefficient variations (C.V.) of 3 samples continuously assayed were 3.8%, 6.5%, and 9.1% and C.V. of 3 samples assayed day by day were 3.6%, 7.2%, and 11.5%. Dilution test revealed that 3 samples diluted to 75%, 50%, and 25% were on each line which go through zero point. After the addition of 5.0, 15.0, and 35.0 mU/ml of EPO to the 3 samples, assay of EPO revealed 95.5 +/- 6.3% (mean +/- SD) of recovery. Assay of EPO in plasma from 19 patients with aplastic anemia revealed that all samples were higher than normal range and that 4 samples from the patients with severe aplastic anemia (less than 8.0 g/dl of hemoglobin) showed higher than 3,000 mU/ml. Furthermore, 67% (14/21) of samples from patients with leukemia showed higher than normal range in EPO concentration. EPO concentration in plasma from 17 patients with chronic renal failure were within normal range although the patients showed anemia.

Adult↗
PubMed1986

[Studies on small thyroid carcinoma in dialysis patients with hyperparathyroidism].

For twenty long-term hemodialysis patients with medically uncontrolled hyperparathyroidism, subtotal parathyroidectomy (PTX) was performed and histological examination was done for 17 out of them, suspected of thyroid disease from operative findings. Thyroid carcinomas were found in 5 out of 17 patients by biopsied specimens of thyroids. Histological findings of carcinomas were follicular (2 cases) and papillary types (3 cases). In all cases, carcinomas were in occult state and the sizes of carcinomas of 4 cases were small being a diameter less than 10 mm. Among others, findings of follicular adenoma (2 cases) and chronic thyroiditis (1 case) were obtained. The incidence rate of thyroid carcinoma in this report seemed to be rather high as the incidence diagnosed from biopsied specimen at operation. Several factors such as immunological incompetence accompanied by renal failure, metabolic abnormalities of cells induced by parathyroid dysfunction and accelerated aging are considered to be involved as a cause of increased incidence of thyroid carcinoma in hemodialysis patients with hyperparathyroidism.

Adenocarcinoma↗
PubMed1986

Development of myofibrils in the gizzard of chicken embryos. Intracellular distribution of structural proteins and development of contractility.

The intracellular distributions of major muscle proteins, myosin, actin, tropomyosin, alpha-actinin, and desmin, in smooth muscle cells of chicken gizzard at various stages of embryogenesis were investigated by immunofluorescence-labeling of enzyme-dispersed cells cultured up to three hours. These muscle proteins, except some part of myosin, were organized into fibrous structures as soon as synthesis and accumulation of proteins started. As for myosin, a considerable amount of it was dispersed in soluble cytoplasm as well. On the other hand, Ca++-dependent contractility was detected with detergent-extracted myoblasts and glycerinated tissue from embryos older than 7 days. Although the nascent myofibrils bear a resemblance to "stress fibers," the former could be distinguished from the latter by their high stability in dispersed, spherical cells. The above findings, therefore, show that the synthesis of contractile proteins is followed by immediate assembly of them into functional myofibrils without undergoing any intermediate structure. Based on these findings, the mechanism of myofibril formation in developing smooth muscle cells is discussed.

Animals↗
PubMed1986

Many isoforms of fast muscle troponin T from chicken legs.

Troponin T from fast muscle of chicken legs was found to be composed of about 40 kinds of isoforms by two-dimensional polyacrylamide gel electrophoresis in conjunction with immunoblotting tests with an antiserum to chicken breast muscle troponin T. Almost all of the isoforms were found in the myofibril preparation and troponin preparation from the leg muscle, and they showed complex-forming ability with troponin I and troponin C. These isoforms existed in most of the fast muscle except pectoralis and posterior latissimus dorsi muscles, and they changed in composition during development. The breast muscle troponin T also showed different types of isoforms in the period soon after hatching. Since proteolysis was completely inhibited during two-dimensional gel electrophoresis and since the many isoforms were observed consistently in various muscles of chicken leg, they are most probably products of mRNAs generated by differential gene splicing.

Animals↗
PubMed1986

Effect of 1,25-dihydroxyvitamin D3 on intestinal disaccharidases in uremic rats.

The effect of 1,25-dihydroxyvitamin D3 (1,25-D) on the activity of intestinal disaccharidases, maltase, sucrase, trehalase and lactase, was studied in five-sixths nephrectomized uremic rats. In uremic rats, maltase, sucrase and trehalase activities were lower than in sham-operated rats. Administration of 1,25-D produced significant improvement of maltase, sucrase, trehalase and lactase activities in uremic rats. These results suggest that activities of intestinal disaccharidases are reduced in uremic rats and these activities are normalized after 1,25-D administration.

Animals↗
PubMed1985

Isolation and characterization of 101-beta-lysozyme that possesses the beta-aspartyl sequence at aspartic acid-101.

In the reaction of the intramolecular cross-linking between Lys-13 (epsilon-NH3+) and Leu-129 (alpha-COO-) in lysozyme using imidazole and 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride [Yamada, H., Kuroki, R., Hirata, M., & Imoto, T. (1983) Biochemistry 22, 4551-4556], it was found that two-thirds of the protein (both the recovered and cross-linked lysozymes) showed a lower affinity than the rest against chitin-coated Celite, an affinity adsorbent for lysozyme. The protein with the reduced affinity was separated on chitin-coated Celite affinity chromatography and found to be slightly different from native lysozyme in the elution position of the tryptic peptide of Ile-98-Arg-112 on reversed-phase high-performance liquid chromatography. In contrast with native lysozyme, the limited hydrolysis of this abnormal tryptic peptide of Ile-98-Arg-112 in 6 N HCl at 110 degrees C gave a considerable amount of beta-aspartylglycine. Therefore, it was concluded that two-thirds of the protein obtained from this reaction possessed the beta-aspartylglycyl sequence at Asp-101-Gly-102. As a result, we obtained four lysozymes from this reaction, the derivative with the beta-aspartyl sequence at Asp-101 (101-beta-lysozyme), the cross-linked derivative between Lys-13 and Leu-129 (CL-lysozyme), the CL-lysozyme derivative with the beta-aspartyl sequence at Asp-101 (101-beta-CL-lysozyme), and native lysozyme. In the ethyl esterification of Asp-52 in lysozyme with triethyloxonium fluoroborate [Parsons, S. M., Jao, L., Dahlquist, F. W., Borders, C. L., Jr., Groff, T., Racs, J., & Raftery, M. A. (1969) Biochemistry 8, 700-712; Parsons, S. M., & Raftery, M. A. (1969) Biochemistry 8, 4199-4205], the same bond rearrangement was detected in the same ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1985

A comparative study of tropomyosin from vertebrate ventricles.

A comparative study of vertebrate ventricle tropomyosin has been carried out from the viewpoint of molecular evolution. The ventricles containing one-component tropomyosin were generally known, and in this paper those containing two components were also found in 8 species among mammals, reptiles, amphibia, and fish, but not among birds. The two components were concluded to be authentic tropomyosin and not artifacts since they showed lower electrophoretic mobilities in the presence of urea, and they were precipitated at pH 4.5 and bound to F-actin. Studies on cysteine contents and cyanogen bromide cleavage peptide patterns revealed that the characteristics of the two tropomyosin components from pig, turtle, amphibia and carp ventricles varied increasingly in that order from typical alpha- and beta-characteristics as seen in rabbit skeletal muscle tropomyosin. The single component of chicken ventricle tropomyosin showed alpha component characteristics in its electrophoretic mobility and cysteine content, and beta component characteristics in cyanogen bromide cleavage peptide pattern. The two components of carp ventricle tropomyosin seemed to be the most primitive, having two cysteine residues per molecule and a cyanogen bromide cleavage peptide pattern different from those of the two components of rabbit skeletal muscle.

Actins↗
PubMed1985

Case report of malignant primary nerve sheath tumor arising in the female pelvis.

This paper reports a malignant primary nerve sheath tumor (MPNST) which originated in the obturator nerve in a 54-year-old woman. That the tumor originated in the nerve sheath is supported by the site of occurrence, which was consistent with the obturator nerve, an arrangement of cells similar to that in schwannoma, and that extracellular basement membrane was noted ultrastructurally. This tumor was classified not as malignant schwannoma but as a nerve sheath fibrosarcoma because the matrix of tumor tissues contained abundant mucinous materials, some tumor cells were fibroblastic, and the clinical change was rapid. In general, with plexiform neurofibroma there is a familial manifestation and it occurs as a complication of von Recklinghausen's disease, associations not demonstrated in this patient. From these findings, this tumor is considered to be an extremely rare nerve sheath fibrosarcoma which originated from a malignant change in a sporadic and solitary plexiform neurofibroma.

Collagen↗