Search PubMed⌕ Search

Biomedical subjects

M Akino

Publications and source records attributed to M Akino.

At least 91 records · Page 5Linked to original sources

[External immobilization of cervical spine with a halo vest--experience with 31 cases].

Post-traumatic or post-operative immobilization of cervical spine often requires long term bed-rest. But, bed-rest indeed gave discomfort to patients, nonetheless, sometimes complete external fixation cannot be gained. Since 1982, we have applied Halo vest to the patients who required external immobilization of cervical spine. In this paper, we reported our experiences with 31 cases who were treated by Halo vest. Thirty-one cases comprised 19 cases of cervical spinal trauma, 5 cases of atlanto-axial dislocation, 1 case of foramen magnum meningioma, and 6 cases of ossification of posterior longitudinal ligament (OPLL). In traumatic cases, Halo vest was used as external fixation of injured spine in 8 cases, and as an adjunct to surgical fusion in other cases. In case of atlanto-axial dislocation, 3 cases underwent posterior fusion, and 2 cases underwent anterior fusion. Anterior fusion of C1-2 was also done in case of foramen magnum meningioma after total excision of tumor. Six cases of OPLL underwent anterior decompression and anterior fusion. Mean immobilization time by Halo vest was as follows: 58 days (28-113) in case of cervical spinal trauma, 85 days (56-144) in case of atlanto-axial dislocation who underwent posterior fusion, 92 days (89-93) in case of atlanto-axial dislocation and foramen magnum meningioma who underwent anterior fusion, 59 days (54-70) in case of OPLL. Early ambulation was achieved in many cases. Good external fixation and result was obtained 27 cases out of 31 cases. Re-dislocation of cervical spine occurred in 1 case of cervical spinal trauma while he was in Halo vest.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Purification, molecular properties and biosynthesis of a specific protein component induced under compensatory hypertrophy in the rat skeletal muscle.

The compensatory hypertrophy in the rat skeletal muscle was induced by the method employing tenotomy and the protein components of the hypertrophied muscle were compared with those of the control muscle by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A protein component, referred to as 64-kDa protein, increased in quantity in the hypertrophied muscle. 64-kDa protein was purified to homogeneity from the extract of the rat skeletal muscle and its molecular properties were studied. Based on criteria which include molecular weight, amino acid composition and immunochemical reactivity, 64-kDa protein was indistinguishable from rat serum albumin. In vitro culture of muscle cells provided evidence showing that 64-kDa protein is synthesized in the muscle cells and rate of its synthesis is significantly greater in the hypertrophied muscle.

Amino Acids↗

Radioimmunoassay for neopterin in body fluids and tissues.

Specific antibodies against D-erythroneopterin have been prepared in rabbits using a conjugate of D-erythroneopterin to bovine serum albumin (D-erythroneopterinylcaproyl-bovine serum albumin). The antiserum distinguished D-erythroneopterin from other pteridines, i.e., three stereoisomers of neopterin, L-erythrobiopterin, folic acid, xanthopterin, and four other synthetic pteridines. Using this specific antiserum, a radioimmunoassay for D-erythroneopterin has been developed to measure the neopterin concentrations in urine and tissues. The conjugate of D-erythroneopterin with tyramine (NP-Tyra) was synthesized and labeled with 125I as the labeled ligand NP-[125I]tyra for the radioimmunoassay. The minimal detectable amount of neopterin was about 0.1 pmol. The concentration of total neopterin (neopterin, 7,8-dihydroneopterin, quinonoid dihydroneopterin, and tetrahydroneopterin) in the biological samples was obtained by iodine oxidation under acidic conditions prior to the radioimmunoassay, and that of neopterin plus 7,8-dihydroneopterin by oxidation under alkaline conditions. Total neopterin values in human urine obtained by this new radioimmunoassay showed a good agreement with those obtained by high-performance liquid chromatography with fluorescence detection. With rat tissue samples which contained very low concentrations of neopterin as compared to biopterin, biopterin was simultaneously determined by our previously reported radioimmunoassay, and neopterin values were corrected for the cross-reactivity (0.1%). The neopterin concentrations obtained by this method agreed with the values obtained by the radioimmunoassays for neopterin and biopterin after their separation by high-performance liquid chromatography. This very small amount of neopterin, as compared with biopterin, in rat tissues could not be determined by high-performance liquid chromatography-fluorometry alone due to the masking of the neopterin peak by a large biopterin peak.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Synthesis of biopterin from dihydroneopterin triphosphate by rat tissues.

High performance liquid chromatography procedure for the analysis of pterins of biopterin synthesis from dihydroneopterin triphosphate via sepiapterin in rat tissues has been described. Sepiapterin-synthesizing enzyme 1, which catalyzes in the presence of Mg2+ the conversion of dihydroneopterin triphosphate to an intermediate designated compound X was assayed by determining pterin which is formed from compound X under acidic conditions. Sepiapterin- and biopterin-synthesizing activity were also assayed by determining sepiapterin and biopterin, respectively. Analytical results revealed the presence of these activities in most rat tissues examined and high levels were found in kidney, pineal gland and liver. Activities were also detectable in peripheral erythrocytes.

Animals↗

Calcification of the ligamentum flavum of the cervical spine. Report of four cases.

Four cases of calcification of the cervical ligamentum flavum are reported, all in women over 60 years of age. Neurological findings were not significantly different from those of other cervical compressive diseases. Among radiological examinations, computerized tomography was the most valuable diagnostic tool. Calcification might have been induced by the degeneration or abnormal nutritional state of the ligamentum flavum. Endocrine abnormalities and inflammatory processes might also have been contributory factors.

Aged↗

The enzymatic synthesis of sepiapterin by chicken kidney preparations.

A chicken kidney preparation which catalyzes the conversion of D-erythro-dihydroneopterin triphosphate to dihydrobiopterin in the presences of Mg2+ and NADPH has been fractionated into three fractions, A2, A1, and B. Fraction A2 in the presence of Mg2+ catalyzes the conversion of D-erythro-dihydroneopterin triphosphate to an unknown intermediate designated compound X. Fraction A1 in the presence of NADPH catalyzes the conversion of compound X to sepiapterin. Fraction B, in the presence of NADPH, catalyzes the conversion of sepiapterin to dihydrobiopterin. Fraction B which is sepiapterin reductase was not studied any further. Fraction A1 is heat-labile and its molecular weight is estimated to be 3.0 x 10(4), whereas fraction A2 is heat-stable and its molecular weight, 7.7 x 10(4). Compound X is labile and its degradation products have been identified to be pterin and pyruvic acid. This information suggests that compound X is 6-(1,2-dioxopropyl)-7,8-dihydropterin.

Alcohol Oxidoreductases↗

Biopterin in human brain and urine from controls and parkinsonian patients: application of a new radioimmunoassay.

Total biopterin concentrations in the post-mortem human brain (caudate nucleus) and in the urine of controls and parkinsonian patients were measured by a newly developed radioimmunoassay. There was good correlation between the total biopterin level and tyrosine hydroxylase activity in the human brain. Biopterin concentrations in the caudate nucleus were greatly reduced in parkinsonian patients. In contrast, the reduction of urinary biopterin in parkinsonian patients was slight and not statistically significant, as compared with normal controls.

Aged↗

Beta-hydroxy-alpha-ketobutyric acid in Drosophila melanogaster, with reference to biosynthesis of drosopterins.

A substance designated as compound D, which reacts spontaneously with 7,8-dihydropterin to give drosopterins, is found in Drosophila melanogaster. The compound was partially purified from the extract of flies by column chromatography and identified as beta-hydroxy-alpha-ketobutyric acid by analysis of its 2,4-dinitrophenylhydrazone, mass spectrometry and reactivity with 7,8-dihydropterin. A highly significant correlation (r=0.969, p less than 0.001) was found between the amounts of the compound and drosopterins in the eye-pigment mutants of Drosophila. Changes of the compound during development of flies were also closely related to those of drosopterins. Based on these observations, a role of the compound in biosynthesis of drosopterins has been discussed.

Animals↗

Effects of melanin on tyrosine hydroxylase and phenylalanine hydroxylase.

Melanin inhibited rat liver phenylalanine hydroxylase, but activated tyrosine hydroxylase from rat brain (caudate nucleus), rat adrenal glands, and bovine adrenal medulla. Activation of tyrosine hydroxylase by melanin was demonstrated with the extensively dialyzed enzyme and in suboptimal concentrations of the substrate (tyrosine) and the cofactor (6-methyltetrahydropterin). Tyrosine hydroxylase from rat brain was activated by melanin more markedly than that from rat adrenal glands. Purified and extensively dialyzed bovine adrenal tyrosine hydroxylase had two Km values with 6-methyltetrahydropterin, depending upon its concentrations, but the melanin-activated tyrosine hydroxylase had a single Km value and showed the classical Michaelis-Menten kinetics.

Adrenal Glands↗

Stoichiometric studies on the oxidation of tetrahydropterin with ferri-cytochrome c.

The oxidation of tetrahydropterin with ferri-cytochrome c was studied using a tetrahydropterin-generating system composed of dihydropteridine reductase [EC 1.6.99.7] and NADH. Under aerobic conditions, 1.5 to 1.8 mol of cytochrome c was reduced per mol of NADH, whereas 2 mol of cytochrome c was reduced under anaerobic conditions. When superoxide dismutase [EC 1.15.1.1] was added to the system under aerobic conditions, only 1 mol of cytochrome c was reduced per mol of NADH, while the pterin oxidation was scarcely affected. Based on these results, we propose that the oxidation of tetrahydropterin to quinonoid dihydropterin proceeds via two steps: tetrahydropterin is first oxidized by ferri-cytochrome c to give a pterin intermediate, which has lost one electron, then in turn this reduces O2 to form O2-.

Cytochrome c Group↗