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Biomedical subjects

R Namba

Publications and source records attributed to R Namba.

53 records · Page 3Linked to original sources
PubMed1990

The reaction product of peptidylglycine alpha-amidating enzyme is a hydroxyl derivative at alpha-carbon of the carboxyl-terminal glycine.

The peptidylglycine alpha-amidating enzyme catalyzes a reaction that transforms a carboxyl-terminal glycine-extended precursor into a carboxyl-terminal alpha-amidated peptide. We purified an alpha-amidating enzyme from equine serum by simplified steps including substrate affinity chromatography. With the purified enzyme, we detected an intermediate of the alpha-amidating reaction by high performance liquid chromatography analysis. The production of the intermediate required copper, oxygen, and ascorbate and increased linearly with incubation time. The structure of the intermediate was determined to be a hydroxyl derivative at the carboxyl-terminal glycine by fast atom bombardment mass spectrometry and by proton NMR. The intermediate was readily converted into an alpha-amidated product in alkaline conditions in a nonenzymic fashion. The nonenzymic conversion required no cofactor but was extremely accelerated by the addition of copper ion or at higher temperature. Our data suggest that the direct product of the alpha-amidating reaction is not an alpha-amidated peptide but a hydroxyl derivative at the alpha-carbon of the carboxyl-terminal glycine.

Amino Acid Sequence↗
PubMed1990

In vitro percutaneous absorptiometry by simultaneous measurement using the photoacoustic method and absorbance.

A novel in vitro percutaneous absorptiometry utilizing a portable open-ended photoacoustic (PA) cell as the longitudinal diffusion cell was developed. With this system it was feasible to measure the reduction of drug applied to a membrane by the PA method and the amount of drug penetrating the membrane to the diffusion cell by absorbance, simultaneously in real time. A shikonin ointment prepared in a hydrocarbon vehicle was used as the model sample. The in vitro percutaneous absorptiometry was performed by means of a physiological saline solution and the skin of a hairless mouse. As a result, after the lag time the absorbance increased in proportion to time, whereas the PA signal reduced in proportion to the square root of time. As the signal obtained by the PA method corresponds to the amount of drug released from the ointment, a good correlation with Higuchi's theory is attained. Consequently, these results suggested the usefulness of this novel percutaneous absorptiometry technique which utilizes the PA method.

Absorption↗
PubMed1990

A case of chronic GM1 gangliosidosis presenting as dystonia: clinical and biochemical studies.

Clinical and biochemical studies are reported on a 32-year-old man with GM1 gangliosidosis who presented with a slowly progressive dystonia that began when he was aged 7 years and eventually became almost totally incapacitating at the age of 35. There was only mild intellectual deterioration, but myoclonus, seizures and macular cherry-red spots were never observed. Proton-density and T2-weighted MRI scans showed symmetrical hyperintense lesions of both putamina. No increase of GM1 ganglioside was found in plasma or cerebrospinal fluid, and the metabolism of GM1 ganglioside in cultured skin fibroblasts from the patient was also almost normal, although the residual activity of GM1 ganglioside beta-galactosidase activity was only 10% of normal. These findings suggest that impaired GM1 ganglioside metabolism is not present systemically as it is in the infantile and juvenile types of the disorder, but is mainly confined to the central nervous system in chronic GM1 gangliosidosis.

Adult↗
PubMed1989

Mitochondrial encephalomyopathy (MELAS): pathological study and successful therapy with coenzyme Q10 and idebenone.

Two patients with mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike episodes (MELAS) in one family are reported. Pathological examination of case 1 showed ragged-red fibers, with 7% of the fibers being unstained by cytochrome c oxidase stain, peripheral nerve damage, multiple areas of softening in the cerebrum and midbrain, and spongy changes in the cerebrum, optic nerve and pons. Electron microscopic examination revealed abnormal accumulations of mitochondria in the skeletal muscle, smooth muscle and cardiac muscle. The activity of cytochrome c oxidase in the brain and liver showed a tendency to decrease. In case 2 (maternal aunt of case 1), muscular weakness and peripheral nerve damage improved by treatment with coenzyme Q10. By adding idebenone to the coenzyme Q10 therapy, the EEG and Wechsler's Adult Intelligence Scale (WAIS) improved. Furthermore, in the cerebral spinal fluid (CSF), the protein, lactate, and pyruvate decreased, and the monoamines and monoamine metabolites increased.

Acidosis, Lactic↗
PubMed1988

Tibial torque generation in a flexed weight-bearing stance.

Internal and external torque generated about the long axis of the lower extremity was measured in 18 male subjects who were instructed to twist with maximal effort against a fixed footplate containing an instrumented torque cell. Mean torque values ranged from 30 to 71 newton meters (Nm) depending upon the test conditions. Torques recorded during the flexed single-leg stance were 19% to 49% higher than those measured while seated. Values at 45 degrees of knee flexion were 11% to 16% greater than those at 20 degrees. Torques generated while wearing a ski boot were 8% to 11% greater than those recorded in an athletic shoe. When movement of the pelvis and upper torso was allowed, torque values were 17% to 49% higher than those recorded when the hips and shoulders were restrained which allowed only lower leg musculature to act in an isolated fashion. There were no differences between internal versus external generated torques when the hips and torso were restrained. When the hips and shoulders were unrestrained, internal torque was 12% greater than external torque. There were no strong correlations between generated torque and body weight or height. These generated torque values suggest that if ski bindings are set to American Society for Testing and Materials (ASTM) standards for twist-release torque, then upper torso and pelvic movement in conjunction with tensed knee musculature (i.e., a "locked knee") may be necessary to accomplish binding release. Use of the lower leg musculature alone (i.e., ankle twist) may not generate sufficient torque for release.

Adult↗
PubMed1987

[An autopsy case of multiple system atrophy with many Lewy bodies--striatonigral degeneration, olivo-ponto-cerebellar atrophy and autonomic nerve nucleus involvement in the spinal cord].

A 72 years old man developed slowness of the motion and orthostatic hypotension at the age of 69. Neurological examination showed slight finger tremor, rigidity of extremities, bradykinesia, and marked orthostatic hypotension. The illness progressed steadily and the patient died of pneumonia. At autopsy brain weighed 1220 g. Grossly the putamen was bilaterally shrunken, the color of the substantia nigra and locus ceruleus became pale. Base of the pons and the cerebellum were atrophic. Microscopically the most remarkable change was seen in the striato-nigral system. In the putamen, there were severe loss of small neurons and intense gliosis and brownish pigments were observed in the neuropil and within some of the astrocytes. There found neuronal loss and gliosis in the substantia nigra. A few Lewy bodies were seen in the substantia nigra. In the cerebellum there were slight loss of Purkinje cell and many torpedos were seen. There were demyelination and fibrirally gliosis in the cerebellar white matter except the hilus of dentate nucleus. The transverse pontocerebellar fibers were degenerated and fibrirally gliosis was seen there. The inferior olivary nuclei showed neuronal loss and astrocytosis. But the degeneration of the olivo-ponto-cerebellar system in this case was not so severe as the typical case of OPCA. In the spinal cord there was depletion of nerve cells in the intermediolateral nuclei and Onufrowitz nuclei. Slight neuronal loss and many spheroids were observed in the anterior horns and there was demyelination in the corticospinal tracts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Effect of internal jugular vein ligation on resorption of cerebrospinal fluid.

The influence of jugular vein ligation on CSF resorption was examined experimentally by means of a manometric ventricular infusion test in dogs. Capacity of CSF absorption was decreased in a stepwise manner according to whether unilateral or bilateral ligation of jugular veins was performed. Interestingly, in addition to rises in ICP, dural sinus pressure was predominantly elevated after bilateral jugular ligation, often exceeding the ICP level. The CSF malresorption observed was considered to be closely related to the lowered pressure gradients between ICP and intracranial sinus pressure.

Animals↗
PubMed1982

[Fundamental and clinical studies of cefotiam in the field of oral surgery].

Cefotiam (CTM) is a new synthetic cephem antibiotic developed in Japan. The results of the fundamental and clinical studies are as follows. 1. CTM showed antibacterial activity, in terms of MIC, as strong as those of cephalothin (CET) and cefazolin (CEZ) for Gram-positive cocci, and several times superior to for Gram-negative bacilli. 2. CTM serum levels approximately reached the peaks on completion of 60 minutes intravenous drip infusion of 1 g of this preparation dissolved in 5% glucose solution of 250 ml; the mean value was 65.00 micrograms/ml. Then the levels dropped rather quickly up to 180 minutes after the start of drip infusion. After that, the levels dropped gradually up to 360 minutes. 3. As for the passage of CTM in the oral tissues, satisfactory passage was observed in both maxillomandibular marrow and gingiva, which adequately exceeded MICs of the clinically isolated strains of oral infections. 4. This preparation was administered 1 g of 2 g daily by intravenous drip infusion in 18 cases of moderate or more serious infections in the field of oral surgery; the clinical efficacy rate obtained was 94.4%. 5. No manifestations of side effect were observed clinically. As for laboratory findings, 1 case of large increases in GOT and GTP (a hepatitis B antigen positive patient) and 2 cases of slight increase in GTP were observed. On the basis of these results of the fundamental and clinical studies, it was concluded that CTM is an excellent antibiotic for the treatment of oral infections.

Adolescent↗
PubMedDate not supplied

Three-dimensional display of the bronchi using helical CT.

The purpose of this study was to evaluate the clinical usefulness of three-dimensional (3D) images of the bronchi obtained using helical CT. Thirteen patients with lung cancer, one with tracheal diverticulum, and one with bronchial amyloidosis were examined. The CT scanner employed was the Toshiba Xforce. The helical CT scan cycle consisted of 20 continuous rotations, each requiring 1.5 sec, for a total scanning time of 30 sec. Scans were obtained using a 5-mm X-ray beam width, a 5-mm/1.5 sec couchtop sliding speed, and a 2-mm reconstruction interval. 3D images were reconstructed using a CEMAX VIPstation. The optimal lower and upper threshold CT values for 3D images of the bronchi were -650 and -100 HU, respectively, and 3D images clearly depicted endobronchial lesions. Cartilage crescents were also demonstrated, but longitudinal and circular mucosal folds could not be visualized. In conclusion, 3D images of the bronchi acquired using helical CT were useful in evaluating endobronchial lesions.

Adult↗
PubMedDate not supplied

Three-dimensional display of pulmonary nodules using helical CT.

To evaluate the clinical usefulness of three-dimensional (3D) images of pulmonary nodules acquired using helical CT, 3D reconstructions were performed in 32 patients using a CEMAX VIPstation. The CT scanner employed was the Toshiba Xforce. Helical CT data were acquired using up to 20 continuous 1.5-sec rotations with an X-ray beam width of 5 mm and a couchtop movement speed of 5 mm/1.5 sec. Axial images were reconstructed at a section interval of 2 mm. The optimal lower and upper threshold CT values for 3D images were as follows: 1) solid pulmonary nodule (-700--400/-100 HU), 2) tumor invading pleura or chest wall (-700--400/-200 HU), 3) pulmonary nodule with cavity (-700--400/50 HU), 4) small pulmonary nodule (< 10 mm) (-750--650/-100 HU), and 5) arteriovenous malformation (180/500 HU). In all cases, it was possible not only to demonstrate abnormal findings three-dimensionally but also to grasp anatomical relationships among the pulmonary nodule, bronchi, vessels, and chest wall.

Adult↗
PubMedDate not supplied

In vitro uptake and release of TI-201 and Tc-99m MIBI in cultured tumor cells and effect of anticancer drug.

201Tl is useful in the diagnosis of tumor malignancy determined by the grade of washout rate to normal tissue, especially in lung tumors and thyroid tumors. 99mTc-MIBI, a tracer of myocardial blood flow, is also a tumor tracer. We examined whether the growth of tumor cells is related to the uptake and release of these tracers in cultured tumor cells. Cultured tumor cells (HeLa cells and squamous cell carcinomas derived from human lung cancer) were incubated for 60 min with 10 kBq of either tracer for the kinetic study of cellular uptake. They were additionally incubated for 90 min with cold medium for the kinetic study of cellular release. These cells cultured with various concentrations of actinomycin D (ACD) or CDDP were used to examine the correlation between the cellular growth and kinetics of these tracers. The cellular release of 201Tl increased relative to the concentration of added ACD or CDDP in both cell types. In contrast, the cellular release of 99mTc-MIBI was not changed by the addition of ACD in HeLa cells. In conclusion, 201Tl showed a slower washout rate in high-growth tumor cells than in low-growth tumor cells; thus, it could act as an indicator of tumor malignancy by assessing its washout rate.

Antineoplastic Agents↗