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M Oata

Publications and source records attributed to M Oata.

At least 19 recordsLinked to original sources
PubMed1975

[Regional cerebral blood flow in senile patients with meningiomas (author's transl)].

We investigated the regional cerebral blood flow of 4 meningioma patients who were all of ages over 60 years old. The average age of the patients was 68 years. Cerebral blood flow was determined by the 133Xe clearance method of Lassen and Ingvar. By extra-cranial recording of the radioactivity from the freely diffusible inert gas 133Xe, which dissolved in saline, was injected into the internal carotid artery, a clearance curve was obtained from the cerebral hemisphere. This curve could be resolved into two monoexponential clearance functions that corresponed to the flow in the grey and white matter. Graphical analysis of the original curve allowed the estimation of the relative weight of these two tissue components as well as of the mean cerebral blood flow. In three patients, regional cerebral blood flow was measured both pre- and post-operatively and these values were compared. Focal rCBF disturbances could be detected in agreement with the tumor location as verified directly or by other diagnostic procedures. That is, a relative hyperemia was detected at the areas corresponding to the tumor site. Mean fg (the flow in the grey matter) of four patients was 77.3 +/- 14.0 ml/100 g/min on the tumor areas, 48.1 +/- 6.6 ml/100 g/min on the peritumoral regions, 63.1+/- 4.1 ml/100 g/min on the non-tumoral regions. CBFr (average cerebral blood flow) of non-tumoral areas in the four patient was 36.6 +/- 2.4 ml/100 g/min and that of the peri-tumoral area, 33.1 +/- 7.9 ml/100g/min. These figures are moderately smaller than that of the normal one. A comparison between the neurological features and regional flow values noted in patients who had a removal of menigiomas indicated that the flow values of non-tumoral area increased markedly a month after operation, instead of only slight or no improvement in neurological features. Although our cases with rCBF studies are still too few to warrant conclusions, it seems that post-operative follow-up of mean cerebral blood flow changes might be rather greater help in the assessment of prognosis after operation of meningiomas than fg (the flow in the grey matter).

Aged↗
PubMed1975

[Radioisotope cisternographic study on cerebrospinal fluid circulation after subarachnoid hemorrhage].

Although recent advance in neurological surgery has diminished mortality rate of aneurysmal surgery, there still exist several complex problems for the management of aneurysms. Persistent neurological deficits or clinical deterioration after subarachnoid hemorrhage can result from subsequent communicating hydrocephalus which can be treated by shunting operation. We have studied alterations in the cerebrospinal fluid (CSF) circulation after SAH in 43 patients. Sources of hemorrhages were aneurysm in 30 cases, arteriovenous malformation in 6 and unknown in 7. Radioisotope cisternography was performed using 0.5 to 1.0 mCi of 169Yb-DTPA which was given intrathecally by lumbar injection. Results of cisternogram were classified into 4 groups and 7 subgroups; group 0: non filling (4%), group I: persistent ventricular filling (45%), A) absence of convexity flow (11%), B) partial convexity flow (34%), group II: transient ventricular filling (23%), A) delayed convexity flow (11%), B) normal convexity flow (12%), group III: no ventricular filling (28%), A) delayed convexity flow (17%), B) normal convexity flow (11%). The radioactivity in serial blood samples was measured by a well-type scintillation counter. Three types of curves for transfer of 169Yb-DTPA from CSF to blood were classified; delayed type, medium type, and normal type. In delayed type, the count ratio of blood activity at 24 hr to that at 3 hr is over 30%. In normal type, it is below 10%. There was a close correlation between cisternogram and transfer curve. In most cases with persistent ventricular filing, the transfer curve showed a delayed type. The relationship of cisternogram to classification of patient's condition by Hunt was studied. The grade of patient's condition was found to be closely related to the degree of abnormality in CSF circulation. The existence of rebleeding in the patients history was also found to influence the degree of abnormality in CSF circulation. However, single bleeding may also cause abnormality, such as persistent ventricular filling on cisternogram. In regard to the site of aneurysms, those of anterior communicating artery appeared to cause communicating hydrocephalus more frequently. Laterality of convexity flow was analyzed in 17 cases. All cases with internal carotid aneurysms showed decreased activity on the side of bleeding. Shunt operation was performed on 10 cases according to the results of cisternography, transfer curve, pneumoencephalography, and angiography. Seven cases showed improvement and 2 died of other complications soon after the shunt, and the effect of the procedure cannot be evaluated. Patients with clinical signs of NPH and abnormal cisternogram (group I) with evidence of ventricular dilatation are indicated for shunting operation.

Adult↗
PubMed1974

The hypercalciurias. Causes, parathyroid functions, and diagnostic criteria.

The causes for the hypercalciuria and diagnostic criteria for the various forms of hypercalciuria were sought in 56 patients with hypercalcemia or nephrolithiasis (Ca stones), by a careful assessment of parathyroid function and calcium metabolism. A study protocol for the evaluation of hypercalciuria, based on a constant liquid synthetic diet, was developed. In 26 cases of primary hyperparathyroidism, characteristic features were: hypercalcemia, high urinary cyclic AMP (cAMP, 8.58+/-3.63 SD mumol/g creatinine; normal, 4.02+/-0.70 mumol/g creatinine), high immunoreactive serum parathyroid hormone (PTH), hypercalciuria, the urinary Ca exceeding absorbed Ca from intestinal tract (Ca(A)), high fasting urinary Ca (0.2 mg/mg creatinine or greater), and low bone density by (125)I photon absorption. The results suggest that hypercalciuria is partly secondary to an excessive skeletal resorption (resorptive hypercalciuria). The 22 cases with renal stones had normocalcemia, hypercalciuria, intestinal hyperabsorption of calcium, normal or low serum PTH and urinary cAMP, normal fasting urinary Ca, and normal bone density. Since their Ca(A) exceeded urinary Ca, the hypercalciuria probably resulted from an intestinal hyperabsorption of Ca (absorptive hypercalciuria). The primacy of intestinal Ca hyperabsorption was confirmed by responses to Ca load and deprivation under a metabolic dietary regimen. During a Ca load of 1,700 mg/day, there was an exaggerated increase in the renal excretion of Ca and a suppression of cAMP excretion. The urinary Ca of 453+/-154 SD mg/day was significantly higher than the control group's 211+/-42 mg/day. The urinary cAMP of 2.26+/-0.56 mumol/g creatinine was significantly lower than in the control group. In contrast, when the intestinal absorption of calcium was limited by cellulose phosphate, the hypercalciuria was corrected and the suppressed renal excretion of cAMP returned towards normal. Two cases with renal stones had normocalcemia, hypercalciuria, and high urinary cAMP or serum PTH. Since Ca(A) was less than urinary Ca, the hypercalciuria may have been secondary to an impaired renal tubular reabsorption of Ca (renal hypercalciuria). Six cases with renal stones had normal values of serum Ca, urinary Ca, urinary cAMP, and serum PTH (normocalciuric nephrolithiasis). Their Ca(A) exceeded urinary Ca, and fasting urinary Ca and bone density were normal. The results support the proposed mechanisms for the hypercalciuria and provide reliable diagnostic criteria for the various forms of hypercalciuria.

Adult↗