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Biomedical subjects

M Manrique

Publications and source records attributed to M Manrique.

10 recordsLinked to original sources

[Vestibular suppression].

Evaluation of the function was carried out by using unilateral caloric test in different arousal status. The goal of this investigation is to further investigate the normal parameters of vestibular function. Maximum speed, latency, frequency, medium speed and number of beats of the slow component of nystagmus were calculated, as well as, the morphological pattern of the standard outline. Voluntary suppression of vestibular response was tested. A test request method was proposed as the best way to fix attention of subjects.

Adult

Medial frontal epilepsy: histological, histochemical, and ultrastructural study. Preliminary observations.

The authors have studied the histological, histochemical, and ultrastructural aspects of eight corticectomies of epileptogenic foci in the medial surfaces of frontal lobes. In all cases they were able to see more gliosis and fewer neurons than normal. The shape and number of dendritic spines were thought to be normal with the Golgi-Cox method. The histochemical study showed an increment of activity of Glucose-6-Phosphatase, Glucose-6-Phosphatedehydrogenase, adenosintriphosphatase, and acid phosphatase. The electron microscope showed, in every case, a variety of changes, among which the authors can point to perivascular lipid accumulation, and an increase of lipofuscin bodies in the cytoplasm of pyramidal cells.

Adolescent

Chronic implanting of electrodes in the cerebellar vermis of the cat. Morphological findings.

The morphological modifications of the cerebellar cortex have been evaluated in eight cats with chronic electrodes implanted in the anterior vermis. In a control animal a silastic lamina without electrodes was implanted. Four animals received intermittent stimulations up to 11 hours in one case and 100 hours in the other 3. The stimulation was carried out with pulses of 0.5 msc, 200 cps, and a charge per phase of 0.68 muc. Microscopic examination of the cerebellum showed that the experimental implanting of prostheses of the cerebellar vermis produces tissue lesions consisting of fibrous reaction, imprinting of the cortex, gliosis, and loss of Purkinje cells. These lesions are independent of the electric stimulation, and seem to be related to the pressure of foreign material against the cortex.

Animals

Cytological alterations in alumina cream experimental epilepsy.

The cellular changes in the neighbourhood of an alumina cream epileptogenic focus and in the mirror focus in chronic experiments in cats have been studied. According to the neuroglial morphology, four layers are described around the alumina cream lesion. At an ultrastructural level, and increase in gap junctions with a great amount of gliofilaments in astroglial processes are observed. There is a decrease in the number of neurons in the vicinity of the alumina cream. Some are coated by glial processes filled with gliofilaments. The dendrites of the pyramidal neurons in the mirror focus show long mitochondria. The possible significance of these data, in relation with the current theories about epileptogenicity, are discussed.

Aluminum Oxide

Chronic paleocerebellar stimulation for the treatment of neuromuscular disorders. Four case report.

4 patients suffering severe neuromuscular diseases were subjected to a subtentorial implantation of electrodes over the anterior cerebellar lobe surface. Chronic stimulation was applied for 90 min to 7 h daily, with a rate of 20--180 Hz, 6--10 V and a schedule of 15 min "on", 15 min "off". Some improvement was observed in 3 patients treated with high frequency stimulation. 1 patient suffered seizures after three months of chronic stimulation. In 2 cases, posterior fossa explorations were necessary for revision of the stimulation apparatus and marked meningeal proliferation surrounding the electrodes was observed. Light and electron microscopic examination of the biopsies showed loss of Purkinje cells and gliofibrillar reaction. Effectiveness and side effects of chronic stimulation of the cerebellum are discussed.

Adult

Cerebral blood flow and behavior during brain stimulation in the goat.

Cerebral blood flow, heart rate, arterial blood pressure, and behavior were studied in conscious goats during electrical stimulation of the diencephalon and mesencephalon. Stimulation of the subthalamic area produced a considerable increase in ipsilateral cerebral blood flow and heart rate, accompanied by either a small or a large increase in systemic arterial blood pressure. Cardiovascular effects were associated with changes in alertness. The increase in cerebral blood flow was partially abolished by previous administration of atropine directly into the internal maxillary artery. Stimulation of the mesencephalic reticular formation caused a marked increase in blood pressure with no change or with some decrease in cerebral blood flow. After administration of phentolamine into the internal maxillary artery, stimulation produced increase in cerebral blood flow. The behavioral response consisted of restlessness and attempted flight. These results suggest the existence of cholinergic vasodilator and adrenergic vasoconstrictor pathways to cerebral blood vessels that may be stimulated electrically.

Animals

[Behavioral manifestations induced by electric stimulation of the anterior cingulate gyrus in man].

The electrical stimulation of a restricted part of area 24 in awake man elicits important behavioral changes. The present study is dealing with 83 epileptic patients whose brain activity was recorded in SEEG conditions, with a view to possible neurosurgery. In order to determine how seizures originate and propagate, 116 multileads electrodes (65 right, 51 left) were stereotaxically inserted in the anterior part of the cingular gyrus. 521 stimulations were performed. In 362 cases, this stimulation induced a particular behaviour which was characterized by an arousal, motor activities (involving fingers and hand, mouth, legs, eyes, associated movements of hand mouth, highly integrated movements), thymic modifications and hallucinatory manifestations. Topographical organization of the effective area in the cingular gyrus and the relation between the electrical responses and stimulation parameters are studied.

Adolescent

Posterior fossa subdural hematoma.

One case of traumatic posterior fossa subdural hematoma (PFSH) is described. This location represent 1% of the subdural hematomas. Computerized Tomography (CT) was used in the diagnosis and follow-up of the hematoma. The etiology and physiopathology of this process are discussed.

Adult