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Biomedical subjects

J Oda

Publications and source records attributed to J Oda.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Clinical evaluation of Fuji computed radiography (FCR) by physicians including non-radiologists].

In Niigata university hospital, most of conventional radiography were changed to FCR from July 1988. To evaluate its clinical utility, questionnaires relating to FCR image were distributed to all physicians including non-radiologists in the hospital after three months. The ratio of the physicians evaluated FCR image to be better than conventional image was 75% in chest radiography, 64% in abdominal radiography. FCR tomography of bone, joint, cranium and chest was also evaluated to be better than conventional by most of the physicians. Reduced size of the film and difficulty in detecting interstitial shadows of the lung were mentioned to be the fault of FCR.

Evaluation Studies as Topic↗
PubMed1989

Crystallization and preliminary X-ray studies of glutathione synthetase from Escherichia coli B.

The glutathione synthetase from Escherichia coli B has been crystallized from 27% saturated ammonium sulfate solution (pH 5.5). The crystals are hexagonal, space group P6(2)22 or P6(4)22. The cell dimensions are a = b = 88.0 A, c = 164.2 A, and gamma = 120 degrees. The enzyme is a tetramer (Mr = 143,000) with 222 symmetry, and the asymmetric unit contains one subunit molecule (Mr = 35,600). The crystals diffract to at least 2.5 A resolution.

Crystallization↗
PubMed1989

Cardiovascular response to exercise in pacemaker implanted patients with fixed heart rate.

Cardiovascular response to supine exercise was studied in 11 patients with chronic ventricular pacing for complete atrioventricular block whose heart rate was fixed during exercise, and compared with 11 age- and sex-matched normal subjects. Oxygen uptake increased linearly with increasing work rate, and attained maximum values of 15.7 +/- 0.7 and 29.5 +/- 1.1 ml/min.kg, respectively. In both groups, cardiac output increased in association with oxygen uptake, although the maximum value in the patients was less than one half that in the controls (6.8 +/- 0.5 and 15.1 +/- 0.3 l/min). Stroke volume, however, could change in patients, as in the controls under similarly increased afterloads (maximum values were 96 +/- 7 and 93 +/- 3 ml/beat, respectively). During exercise, the systolic arterial pressure elevated to a similar extent in both groups (221 +/- 14 and 235 +/- 12 mmHg, respectively). The increase in stroke volume in the patients was achieved by complete systolic emptying and the Frank-Starling mechanism. It is considered that in patients with ventricular pacing, exercise can produce an increase in stroke volume when myocardial function is not impaired.

Aged↗
PubMed1989

[Factor analysis of bone mineral dynamics in patients with renal osteodystrophy].

Remarkably high accumulation of Tc-99m-MDP is seen in the skull on bone scintigraphy of patients with renal osteodystrophy (ROD), especially with secondary hyperparathyroidism. For the quantitative evaluation, the Factor Analysis (FA) was used for the early phase of bone scan. Tc-99m-MDP (14.8 MBq/body weight kg) was injected as a bolus through the medial antecubital vein. Dynamic acquisition of 40 x 30 sec frames were performed in a 64 x 64 matrix. For pre-processing, nine points smoothing was carried out, and then the region of interest was set on the frontal image of the head for the FA. The FA was performed with an 8 x 8 sampling corresponding to 64 dixels from 4,096 dixels. Bone factor was clearly extracted by the FA. Then, two original parameters were calculated. One is the bone radionuclide uptake counts (Bu) which is the product of the total radionuclide counts of skull and the contribution ratio, the other is the uptake ratio (Br) derived by the time activity curve (physiological component) of the FA. These parameters of ROD were significantly different compared to those of controls. The FA seems to be useful in quantitative evaluation of bone mineral dynamics.

Adult↗
PubMed1988

Role of cysteine residues in glutathione synthetase from Escherichia coli B. Chemical modification and oligonucleotide site-directed mutagenesis.

Escherichia coli B glutathione synthetase is composed of four identical subunits; each subunit contains 4 cysteine residues (Cys-122, -195, -222, and -289). We constructed seven different mutant enzymes containing 3, 2, or no cysteine residues/subunit by replacement of cysteine codons with those of alanine in the gsh II gene using site-directed mutagenesis. Three mutant enzymes, Ala289, Ala222/289, Cys-free (Ala122/195/222/289), in which cysteine at residue 289 was replaced with alanine, were not inactivated by 5,5'-dithiobis(2-nitrobenzoate) (DTNB), while the other four mutants retaining Cys-289 were inactivated at the wild-type rate. From these selective inactivations of mutant enzymes by DTNB, the sulfhydryl group modified by DTNB was unambiguously identified as Cys-289. In this way, Cys-289 was found to be also a target of modification with 2-nitrothiocyanobenzoate and N-ethylmaleimide, while Cys-195 was of p-chloromercuribenzoate. These results suggest that both Cys-195 and Cys-289 were not essential for the activity of the glutathione synthetase, but chemical modification of either one of the two sulfhydryl groups resulted in complete loss of the activity. Replacement of Cys-122 to Ala-122 enhanced the reactivity of Cys-289 with sulfhydryl reagents.

Alanine↗
PubMed1988

Intervertebral disc changes with aging of human cervical vertebra. From the neonate to the eighties.

The infantile nucleus pulposus is occupied by tissue derived from the notochord. The nucleus pulposus of this type is replaced by a different type of nucleus pulposus, composed of fibrocartilage and dense fibrous tissue at the first half of the second decade. In the adult, the nucleus pulposus shows morphologically high cell activities near the cartilaginous end-plate, including a process suggestive of regeneration. The surface layer of the cartilaginous end-plate and adjacent layer of the nucleus pulposus seems to play an important role in the maintenance of the nucleus pulposus. Both the calcification within the cartilaginous end-plate, accompanied by bone formation, and its superficial detachment, seems to destroy this layer and lead up to the obliteration of the disc.

Adolescent↗
PubMed1987

Homology of Escherichia coli B glutathione synthetase with dihydrofolate reductase in amino acid sequence and substrate binding site.

Glutathione synthetase from Escherichia coli B showed amino acid sequence homology with mammalian and bacterial dihydrofolate reductases over 40 residues, although these two enzymes are different in their reaction mechanisms and ligand requirements. The effects of ligands of dihydrofolate reductase on the reaction of E. coli B glutathione synthetase were examined to find resemblances in catalytic function to dihydrofolate reductase. The E. coli B enzyme was potently inhibited by 7,8-dihydrofolate, methotrexate, and trimethoprim. Methotrexate was studied in detail and proved to bind to an ATP binding site of the E. coli B enzyme with K1 value of 0.1 mM. The homologous portion of the amino acid sequence in dihydrofolate reductases, which corresponds to the portion coded by exon 3 of mammalian dihydrofolate reductase genes, provided a binding site of the adenosine diphosphate moiety of NADPH in the crystal structure of dihydrofolate reductase. These analyses would indicate that the homologous portion of the amino acid sequence of the E. coli B enzyme provides the ATP binding site. This report gives experimental evidence that amino acid sequences related by sequence homology conserve functional similarity even in enzymes which differ in their catalytic mechanisms.

Amino Acid Sequence↗
PubMed1987

[The availability of digital subtraction angiography using continuous intra-arterial infusion tubes founded various malignancy].

DSA was employed using continuous intraarterial infusion tubes for various malignancies (73 cases) which were examined a total of 135 times. In head and neck malignancy (50 cases), the general position of the infusion tube had been determined beforehand by dye infusion, but DSA from the tube showed that the tubes in 24 cases (48%) were located in the wrong position, especially in tongue cancer (21 cases) where many tubes were discovered to be in an erroneous position (71%) such as the common carotid artery. We were unable to determine the effect of chemotherapy and radiation using DSA only. In 9 cases of breast cancer for which fixation of the tube was not attempted under X-ray fluoroscopy, 7 (78%) showed an unusual tube position such as the intraaortic arch. In 5 cases of abdominal malignancy, only the tube position for sigmoid colon cancer was unusual. We were able to observe the effect of chemotherapy by DSA in 2 cases. For DSA in one out of 3 hepatomas using a Port-A-Cath, we observed that infusion of anticancer drug with degradable starch microspheres caused a reduction in tumor size. However, in the two remaining cases, we were unable to observe any effect of infusion of these drugs by DSA for various mechanical reasons. DSA from an infusion tube revealed not only the location of the tube accurately and promptly, but also the effect of chemotherapy.

Angiography↗
PubMed1986

Pituitary dwarfism: CT evaluation of the pituitary gland.

The pituitary glands of 12 patients, aged 4-20 years, with pituitary dwarfism and of 15 age-matched control patients were evaluated with contrast-enhanced, high-resolution computed tomography (CT). In control patients, CT clearly demonstrated pituitary glands and stalks, 2.5-9.0 mm in height (average, 5.7 mm +/- 1.8). In the 12 patients with pituitary dwarfism, CT did not demonstrate the gland or stalk in four; CT faintly showed only the stalk in another four and showed a small gland (less than 2 mm in height) and a small to normal stalk in the remaining four. Eleven of the 12 patients had a birth history of breech presentation. Possible causes of pituitary dwarfism are discussed.

Adolescent↗
PubMed1985

Serial determinations of serum enzymes following aorta-coronary bypass surgery and acute myocardial infarction.

Serial determinations of serum creatine kinase (CK), cardio-specific isoenzyme of CK (CK-MB), glutamic oxaloacetic transaminase (GOT) and alpha-hydroxybutylate dehydrogenase (HBD) were made in 29 consecutive patients undergoing aorta-coronary (AC) bypass grafting, and the results were compared with those in 31 patients with acute myocardial infarction (AMI). Postoperatively, all patients had an uneventful postoperative course and there was no evidence of AMI. The time course of enzyme activity following surgery was characterized by 1) shortening of peak activity time of all enzymes except CK, 2) rapid disappearance of CK-MB, 3) prolonged normalization of GOT and HBD. Peak activities of CK, CK-MB, GOT and HBD in AC bypass patients were 801 +/- 77, 46 +/- 6, 100 +/- 9 and 718 +/- 32 IU (mean +/- SEM), respectively, which were equivalent to 46%, 12%, 22% and 47% of those in AMI. The degree of postoperative CK-MB elevation was influenced by the duration of the operation and the extracorporeal circulation, and the number of grafts bypassed. The peak CK-MB activity did not correlate with the CK peak. The ratio of CK-MB to CK was much smaller in AC bypass than in AMI (6.5 +/- 1.8 vs. 20.1 +/- 1.4%). It was concluded that serum enzyme elevations after AC bypass surgery largely reflected enzyme release from the skeletal muscle rather than the myocardium.

Adult↗