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Biomedical subjects

S Okajima

Publications and source records attributed to S Okajima.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Evaluation of treatment planning of radiotherapy for lung cancer].

Treatment of lung cancer in radiotherapy was evaluated by considering damages to normal tissues. Small and large tumors were examined for two portals, rotational and conformation irradiation. The considered damages were irreversible late effects in lung and injury to spinal cord. For the small tumor of 3.5 cm in diameter, rotational irradiation showed the smallest damage. For the large tumor of 12 cm X 10 cm in cross section, conformation irradiation resulted in the smallest damage.

Evaluation Studies as Topic↗
PubMed1984

Kinetics of human pancreatic and salivary alpha-amylases with carboxymethylamyloses as substrates.

The enzymatic measurement of alpha-amylase in human serum with chemically modified amylose as substrate was studied. Several substitutions of carboxymethylamylose were prepared from amylose, suitable amounts of monochloroacetic acid, and sodium hydroxide. The relationship between the degree of substitution of the carboxymethylamylose and the kinetic parameters of human pancreatic, salivary and porcine pancreatic alpha-amylases was determined. The action of alpha-amylases on such modified amyloses in the presence of glucoamylase was measured by a specific enzymatic assay having glucose as the product. The kinetic parameters of human pancreatic alpha-amylase were similar to those of human salivary alpha-amylase. It was possible to determine suitable sensitivities for the alpha-amylase assay using this substrate. These results suggested a subsite model.

Amylose↗
PubMed1984

The effect of a hypoxic cell sensitizer on cancer radiotherapy: an analysis by a model.

Misonidazole has been studied for its sensitizing effect of radiation on hypoxic cells in vitro and in vivo. However, clinical trials have not always shown improvement of cure rate in radiotherapy. The enhancement ratio when irradiation was performed with misonidazole was analysed by a model to examine the effectiveness of misonidazole, considering the hypoxic fraction in cancer and reoxygenation. It was shown from this model that misonidazole should be effective for cancer which had a hypoxic fraction of more than 10%, and in which reoxygenation did hardly occur, and that the effect of misonidazole was not dependent on the size of dose per fraction for radioresistant cancer.

Humans↗
PubMed1983

Relationship between cure rate of human cancer and delivered dose in radiotherapy.

The cure rate of tumors was analysed by a model, and applied to human cancer. The cure rate increased linearly when plotted on a probit scale against dose in logarithm. The coefficient of variation, the ratio of one standard deviation to the dose of 50% cure, was taken as an indicator. The minimum value of the coefficient of variation was 5% obtained theoretically, and 10% clinically. This difference might be due to the variability existing in cancer of patients. The complications to the normal tissues, which was induced by the radiotherapy of cancer, were also analysed. The coefficient of variation for the complication showed the same tendency to that of the cure rate. The cures without complications were affected by the coefficients of variation for the cure rate and for the complication rate. The coefficient of variation for the cure rate is determined by the stochastic effect of cell killing and the error in dose estimation. When the physical error was 5%, its effect on the cure rate could be negligible. But when its error became more than 10%, a significant difference of the cure rate would be observed clinically in some tumors. The accuracy of the dose estimation was emphasized.

Dose-Response Relationship, Radiation↗
PubMed1981

Exercise stress body surface isopotential map in patients with coronary artery disease: comparison with coronary angiographic and stress myocardial perfusion scintigraphic findings.

to locate the ischemic area in 22 patients with angina pectoris, exercise stress body surface isopotential maps (MAPs) were assessed and compared with coronary angiography and myocardial stress scintigraphy. Taking coronary angiographic findings into consideration, 4 types of ischemic MAP responses, i.e., septum and anterior, lateral, inferior, and posterior wall ischemia were postulated. Sensitivity of stress MAP was 71% for the average and more than stress imaging. Specificity of stress MAP was 46% for the average and less than stress imaging.

Angina Pectoris↗
PubMed1980

Adult-onset vitamin D-resistant osteomalacia with the unresponsiveness to parathyroid hormone.

Serum immunoreactive parathyroid hormone (PTH) levels were increased in a 50-yr-old man with a unique variant of adult-onset vitamin D-resistant osteomalacia, presenting with high phosphate clearance, mild hypocalcemia, and blunted hypercalcemic and phosphaturic responses to exogenous parathyroid extract. After normalization of his serum calcium level with a large amount of 1 alpha-hydroxycholecalciferol, a synthetic vitamin D analog, serum PTH levels and phosphate clearance returned to normal, and hypercalcemia as well as phosphaturia appeared when parathyroid extract was administered. Further studies demonstrated that the renal response could be restored by the administration of calcium with the suppression of PTH. The evidence presented suggests that the resistance of PTH in this patient was due to secondary hyperparathyroidism rather than to a defect of PTH-sensitive receptors of the kidney and bone or to inadequacy of vitamin D per se.

Calcium↗
PubMed1980

Non-invasive localization of the pre-excitation site in patients with the Wolff-Parkinson-White syndrome. Vectorcardiographic and echocardiographic correlations.

Vectorcardiographic and echocardiographic correlations were made in 160 patients with no clinical evidence of cardiovascular diseases except for the Wolff-Parkinson-White syndrome. Frank vectorcardiographic classifications of the patients were based on both the morphology of the delta loop and the direction of the mean delta vector in the horizontal plane as follows; group I (93 patients) with a delta loop inscribed nearly straightly anteriorly and either to the left or right and a mean delta vector directed more anteriorly than +20 degrees, group II (31 patients) with a hook-shaped delta loop inscribed initially anteriorly but soon posteriorly and to the left, and group III (36 patients) with a delta loop inscribed nearly linearly to the left and either posteriorly or slightly anteriorly and a mean delta vector directed more posteriorly than +20 degrees. Abnormal echocardiographic patterns of ventricular contractions in the syndrome were seen at the left ventricular posterior wall (LVPW), the interventricular septum (IVS), and the right ventricular anterior wall (RVAW). In group I abnormal LVPW motions were observed in 91 patients (98%), and both abnormal LVPW and IVS motions in 1. The remaining 1 showed no echocardiographic abnormalities either at LVPW or IVS. In contrast, abnormal IVS motions were observed in 29 patients (94%) of group II. No patient of group II showed abnormal LVPW motions. In 17 patients (47%) of group III abnormal LVPW motions alone were observed. Two patients showed both abnormal LVPW and IVS motions. In the remaining 17 patients (47%), no abnormal motions were noted either at LVPW or IVS. Abnormal RVAW motions were invariably observed in 19 patients of group II with satisfactory RVAW echograms, but never seen in groups I and III. Above findings could be explained by the pre-excitation at LVPW in group I, RVAW in group II, and posterior right ventricle in group III. In 19 patients (8 in group I and 11 in group III) frontal QRS loops were very similar to that in left anterior hemiblock. All of these patients except for 1 showed abnormal LVPW motions, so that the site of pre-excitation was presumably located at the posterior paraseptal region or the posterior IVS. Three cases with a combination of a frontal QRS loop of left anterior hemiblock pattern and abnormal IVS motions in addition to abnormal LVPW motions may be explained by the pre-excitation at the right-sided IVS near LVPW. We feel that combinations of vectorcardiographic and echocardiographic approaches are clinically quite useful as an auxiliary non-invasive means of locating the pre-excitation site.

Adolescent↗
PubMed1980

Comparison of Frank-vectorcardiograms of normal conduction and right bundle branch block in patients with intermittent or transient right bundle branch block.

For the purpose of obtaining fundamental data to make the diagnostic criteria for coexisting electrocardiographic abnormalities in right bundle branch block (RBBB), the Frank-vectorcardiographic and electrocardiographic parameters were studied in both normal and RBBB conductions in 25 patients (16 males and 9 females, aged 6 to 78 years) with intermittent or transient RBBB. There were no statistically significant differences in the corresponding instantaneous QRS vectors between normal and RBBB conductions during the first 10.4 (+/- 3.2) msec of the QRS duration on the average. No statistically significant differences existed in the mean Q amplitudes of the Frank leads between normal and RBBB conductions. After the development of RBBB, voltages of Rx and Ry, and the planar maximum QRS vectors decreased approximately by 10% on the average, and Rz decreased significantly by 63.9% on the average, and S amplitudes of the 3 Frank leads increased significantly. We observed 3 patients showing a complete reversal of the sense of inscription of the horizontal QRS loop from counterclockwise to clockwise after the development of RBBB. Two of these patients showed no clinical evidence of cardiac or pulmonary diseases except for RBBB. After the appearance of RBBB, maximum T vectors deviated significantly posteriorly in the horizontal and left sagittal planes. Twenty-three patients showed counterclockwise inscription of the T loop both in the horizontal and left sagittal planes, and 9 patients in the frontal plane. After the development of RBBB, we observed a complete reversal in the sense of inscription of the T loop from counterclockwise to clockwise in 13 cases (56.5%) in the horizontal plane, in 15 cases (65.2%) in the left sagittal plane, and in 8 cases (88.9%) in the frontal plane.

Adolescent↗