Biomedical subjects
Publications and source records attributed to J A Byer.
Neurological assessment of certain movement disorders is described with emphasis on Parkinson's disease. In addition, abnormal behavior and changes in affect are given. Changes in neurological status, i.e., Bradykinesia, rigidity, gait changes, hand-writing irregularity, postural reflexes are outlined. The differential diagnosis of the disease is also indicated in addition to prognosis and to the biochemical correlates of Parkinson's disease.
We studied the effect of several clinically important variables on the characteristics of alpha 2-adrenergic receptors in human platelet membranes. The number and affinity of the receptor binding sites were determined from radioligand binding experiments, with [3H]yohimbine being the radioligand of choice. Platelets from female subjects had a cyclic variation in the number of alpha 2-adrenergic receptors that coincided with their menstrual cycles. The number of alpha 2-receptors was highest at the onset of menses and dropped to 74% to 79% of that value during the middle of the cycle. In concurrent experiments we did not observe comparable cyclic changes in receptor binding sites in platelets from male subjects. There was no age-dependent alteration in receptor number in a sample of 39 subjects ranging in age from 8 to 80 yr, but the number of alpha 2-receptors in platelets from male and female subjects differed. We also tested the possibility of a circadian rhythm in alpha 2-receptor number but found no cyclic changes as a function of time of day. There was no alteration in alpha 2-adrenergic receptor binding in the platelets from five subjects with Parkinson's disease. Finally, there was no change in receptor affinity as a function of any of the variables tested. These data should apply to the design of further studies on the clinical importance of platelet alpha 2-adrenergic receptors.
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The records of 100 consecutive cases of subarachnoid hemorrhage due to ruptured aneurysm were reviewed to determine the incidence and the prognostic implications of seizures during the acute phase. Seizures occurred in 26% of the patients. Sixty-three per cent of the seizures occurred near the onset of the initial hemorrhage. The occurrence of these early seizures did not correlate with the location of the aneurysm or the prognosis. Most of the remaining seizures occurred immediately after rebleeding, with no greater morbidity or mortality compared to all patients who rebled. Pathogenic mechanisms of seizures associated with subarachnoid hemorrhage are proposed and discussed.
An organist had an episode of transient global amnesia during a recital. Despite a severe immediate-memory deficit, he performed complex organ music. This case suggests that the localization of the cerebral deficit in transient global amnesia is distinct from the cerebral centers necessary for performance of instrumental music.
Major advances are being made in our understanding of the pathophysiology of ischemic stroke. In the past 25 years anticoagulation, carotid endarterectomy, and antiplatelet aggregation agents, along with less well-accepted therapies, have been introduced for the management of this complex disorder. Also, noninvasive diagnostic methods have been developed for evaluating these patients. This article reviews the pathophysiology of cerebral ischemia and the data on the effectiveness of the various therapies advocated for its management.
In an attempt to prevent morbidity and mortality in carotid endarterectomy, we monitored 47 operations with intraoperative EEG to determine which patients should have a shunt during endarterectomy. The EEG was recorded for up to five minutes during test carotid cross-clamping. When EEG asymmetry between the cerebral hemispheres occurred, the clamp was immediately removed. A shunt was used in all patients who had EEG asymmetry. In the absence of EEG asymmetry, no shunt was used. Of the 38 patients with no EEG asymmetry intraoperatively, one patient had transient deficits postoperatively. Electroencephalographic asymmetry occurred in nine patients during test carotid cross-clamping. Postoperatively, five of these shunted patients awakened neurologically intact and four patients had transient deficit. When the EEG was normal and no shunt was used, patients did well; when the EEG was abnormal and a shunt was used, there was a high incidence of transient neurologic deficit.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.