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Biomedical subjects

O S Marin

Publications and source records attributed to O S Marin.

13 recordsLinked to original sources

Transient global amnesia: an extensive case report.

A case of transient global amnesia was studied in detail. Of note was a temporally extensive, although quite patchy, retrograde amnesia during the event for information recallable at other times. While a consolidation block can explain the anterograde amnesia in transient global amnesia, the profound retrograde amnesia requires an additional block in the retrieval of old, established memories.

Amnesia

[Nature of repetition disorders in conduction aphasia].

The skeptic over the existence of this important clinical entity, are now very few. Anatomo-clinical studies and the analysis of altered cognitive procedures suggest, however, that we are dealing with a heterogeneous group. Two models of conduction apahasias are presented, in which the mechanism of the altered repetition, as well as the probable localization of the lesion, differ considerably. One has a lesion in the posterior parietal region of the left hemisphere and it exemplifies an acoustic verbal memory deficit (short term memory). The other points at a functional disconnection between the decodification and verbal processes and those of expression. In this case, we are dealing with a left temporal lesion in a left-handed individual. The analysis of our material and of the clinical literature upholds the idea of a plurality of the altered mechanisms in the verbal repetition and suggest that the conduction aphasia is a syndrome.

Adolescent

Mechanism of the inverted supinator reflex. A clinical and neurophysiological study.

The inverted supinator reflex sign was analysed in two patients by recording the response of the finger flexor muscles of the forearm to tapping of the styloid process of the radius before and after procain infiltration of these muscles. It was found that the response persisted despite the block. The findings support the concept that the underlying mechanism is increased alpha motoneurone excitability below the level of the lesion; however, a possible contribution of the dynamic muscle spindles could not be excluded.

Evoked Potentials

Agnosic behavior in anomia: a case of pathological verbal dominance.

The interrelation of perceptual and verbral process was explored in a fluent aphasic with a naming disorder. This patient performed extremely well on complex perceptual tasks as long as he was instructed to remain silent or to count aloud. Whe he began to talk about what he was doing, he misnamed many test items and behaved as if they were what he had called them. The verbal interference effect is explained in terms of cerebral dominance and interhemispheric interaction and it is suggested that a similar mechanism may apply in classical cases of agnosia.

Agnosia

Cardiac arrhythmias and sudden death in subarachnoid hemorrhage.

Life-threatening cardiac arrhythmias can occur in patients with subarachnoid hemorrhage secondary to rupture of intracranial aneurysms. The arrhythmias are secondary to acute dysfunction of the central nervous system and possibly to sudden increase in intracranial pressure. The autonomic nervous system is the mediator in the production of these disorders. The clinical significance of these rhythm disorders is discussed, particularly in regard to the sudden, unexpected death seen in this type of patient. The possible mechanisms of production are analyzed and their therapeutic implications are stressed.

Adult

Atheromatous emboli to the lumbosacral spinal cord.

The lumbosacral spinal cords of 28 patients with atheromatous emboli to abdominal viscera and/or grafts to the abdominal aorta were examined by serial sections. In 12 patients, atheromatous emboli were found in spinal arteries, most commonly in the sacral cord, and most frequently in the anterior spinal artery. The general absence of spinal cord infarctions was attributed to the nature of the emboli, apparent good collateral circulation, and the absence of diffuse atherosclerosis. However, 38% of the patients had arteriosclerosis; this was generally focal and not associated with significant luminal narrowing. Only one patient had infarction, which was limited primarily to the gray matter. It would appear that hypoperfusion must exist in conjunction with atheromatous emboli in order for infarction to develop. Organized atheromatous emboli also caused focal ischemic atrophy of neurons. It is postulated that this change may be the morphological basis for some of the atypical lower motor neuron diseases found in the elderly.

Arteriosclerosis