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Biomedical subjects

S Uematsu

Publications and source records attributed to S Uematsu.

At least 145 records · Page 8Linked to original sources

Absence status (petit mal status) with focal characteristics.

Two patients, aged 23 and 74 years, manifested prolonged episodes of mildly impaired consciousness in conjunction with rhythmical spike waves or spikes (mostly 3/s). This paroxysmal EEG activity was consistently accentuated unilaterally over the superior frontal regions. The first patient showed ictal aphasia and occasional right hemiparesis during these episodes, and partial left frontal lobectomy resulted in temporary freedom from seizures. The classification of these ictal episodes is difficult. They apparently fall into the category of absence status (petit mal status), but the focal neurological signs do not fit the presently valid definitions of absence status, nor does the lack of symmetrical bilateral-synchronous paroxysmal discharges. Perhaps a special category of status epilepticus should be established.

Adolescent↗

Pulsatile cerebral echo in diagnosis of brain death.

Conclusive diagnosis of brain death can be made by the demonstration of prolonged cessation of cerebral blood flow. This report describes a simple method to determine the presence or absence of the blood flow in the brain by recording the pulsatile midline echo on one channel of the electroencephalogram (EEG) or on any four-channel monitoring system in the intensive care unit. A firm transducer holder has been developed to eliminate artifacts caused by transducer motion, The pulsations of the midline echo are assumed to be the result of displacement of the midline structures by the arterial injection of each cardiac systole. Thus, the absence of these midline pulsatile echoes correlates with the absence of cerebral blood flow and, if the absence persists over 30 minutes in the presence of normal blood pressure, then the result is brain death. Twenty-eight cases of clinical brain death with electrocerebral silence of EEG and 18 obtained patients with various types of cerebral pathology were examined by the echo-pulsation technique. Twenty-six of the 28 cases showed no pulsation of the midline echo. The validity of the technique was documented in four cases by four-vessel cerebral angiogram.

Adolescent↗

Histological reaction to various conductive and dielectric films chronically implanted in the subdural space.

Thirty different test patches of various thin film materials were chronically implanted in the subdural space of cats to determine their suitability as components for proposed neuroprosthetic devices. In particular, materials employed by the microelectronics industry were screened, and reactions were found to be quite dependent on specific formulations or surface preparations of otherwise similar materials. A nonspecific but severe complication of pressure necrosis under thin films that spontaneously roll and curl in vivo was noted.

Animals↗