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Biomedical subjects

S Lavy

Publications and source records attributed to S Lavy.

At least 37 records · Page 2Linked to original sources
PubMed1977

Changes in local brain tissue Po2 and electrocortical activity of unanesthetized rabbits under high oxygen pressure.

Po2 changes in the thalamus, hippocampus, reticular formation, and cortex, and cortical electrical activity, were recorded simultaneously in unanesthetized, unrestrained rabbits breathing air or hyperbaric oxygen. The average tissue Po2 of investigated brain structures during exposure to 100% oxygen at 7 ATA pressures, was two to three times greater than that during air breathing at 1 ATA. In seven out of 10 rabbits, successive myoclonic fits were observed before the appearance of the first electrical discharge or abnormal EEG. Postmortem examination of the lungs showed signs of edema and hemorrhage in all the animals. Because of the possibility that the lung damage took place before the development of brain oxygen toxicity, we concluded that the rabbits are not animals of choice for the investigation of brain oxygen toxicity. The possible interrelationship between cerebral metabolic rate-O2, cerebral blood flow, and lung pathology in determining the level of tissue Po2 and the appearance of oxygen toxicity in the brain under hyperbaric conditions are discussed.

Animals↗
PubMed1976

Aseptic cavernous sinus thrombosis after internal carotid arterial occlusion in polycythaemia vera.

Two patients with untreated polycythaemia vera developed intracranial internal carotid arterial occlusion followed by monocular blindness and the characteristic features of ipsilateral cavernous sinus thrombosis. Primary septic source and signs of systemic infection were absent. It is suggested that the predisposing factors in this unusual syndrome were hyperviscosity and venous sludging induced by the basic haematological disorder and progression of the thrombotic process within the internal carotid artery towards its intracavernous portion with occlusion of the ophthalmic artery and of the arterial branches which supply the walls of the sinus.

Adult↗
PubMed1976

Interictal regional cerebral blood flow in patients with partial seizures.

Interictal regional cerebral blood flow was determined in 11 adult patients with partial epilepsy and lateralized electroencephalographic abnormalities by means of the xenon 133 intracarotid injection method. A hemispheric area demonstrating significantly low regional cerebral blood flow values as compared with the hemispheric mean cerebral blood flow was observed in each of the patients. In 10 of the 11 patients the localized reduced regional cerebral blood flow levels deviated significantly from levels obtained from parallel regions and hemispheres of normal controls. In the majority of patients, the site of low regional cerebral blood flow closely correlated with the clinical type of partial seizures and/or the site of main electroencephalographic abnormality. On the basis of these data, we suggest that the epileptogenic focus responsible for the partial seizures may be localized within the hemispheric area demonstrating the abnormal regional cerebral blood flow reduction.

Adult↗
PubMed1975

Correlation between regional cerebral blood flow and EEG frequency in the contralateral hemisphere in acute cerebral infarction.

The relationship between the rCBF and the electroencephalographic (EEG) frequency was investigated in the contralateral hemisphere of 22 patients with acute cerebral infarction. Reduced rCBF was observed in all patients studied. The degree of rCBF reduction was mild, moderate, or severe and ranged between 6 and 80% from the lowest age-matched normal values obtained in our laboratory. The frequency indices remained within normal limits (mean - 10.4 Hz) in 16 patients. Slower frequencies (mean - 6.3 Hz) were recorded in 6 patients. No correlation was found between the two parameters (P = 0.89). Both the EEG frequency and the rCBF are known to be closely related to the cerebral metabolic rate. The observed rCBF depression without concomitant changes in the EEG frequency raises the question of the role of globally-reduced cerebral metabolism as the cause of rCBF reduction in the noninfarcted hemisphere in stroke patients. Our findings constitute additional evidence that the contralateral hemisphere is involved in the haemodynamic changes occurring in acute cerebral infarction.

Acute Disease↗
PubMed1975

Prognostic value of visual evoked potentials in occipital blindness following basilar artery occlusion.

Three patients suffering from sudden occipital blindness following basilar artery occlusion underwent electroretinography and visual evoked potential (VEP) examinations. The VEPs performed early in those blind patients and repeated later seem to be of prognostic value. Responses of normal shape and amplitude after monocular and binocular stimulation were followed by complete recovery of vision. Unequal and subnormal VEPs obtained following monocular stimulation, and even smaller responses reached after binocular stimulation, accompanied permanent unilateral occipital damage resulting in homonymous hemianopsia. Lack of VEP was proved to be a preceding sign of permanent blindness.

Aged↗
PubMed1975

Central nervous system complication in a patient with chronic gaucher's disease.

Central nervous system manifestations developed in a patient suffering from the chronic, adult form of Gaucher's disease. At autopsy, massive systemic fat embolism was found, involving mainly the brain and the lungs. As there was no evidence of bone fracture, or trauma to the adipose tissues, it is presumed that the severe skeletal involvement by the Gaucher's disease led to the development of the fat embolization.

Autopsy↗
PubMed1975

Chronic subdural hematoma simulating transient cerebral ischemic attacks. Case report.

A patient is presented in whom chronic subdural hematoma simulated transient ischemic attacks. The neurological manifestations were those of recurrent, transient episodes of expressive dysphasia preceded by focal sensory deficit. Various pathophysiological mechanisms which could have caused the unusual clinical picture are briefly considered.

Aphasia↗
PubMed1975

Excitability of the cortex in normal and adrenalectomized rats during repeated exposures to high oxygen pressure.

The excitability of the cortex in adrenalectomized and normal adult male rats to High Oxygen Pressure (HOP) was studied 2, 3, 4, 6, 8, 12 and 22 d after bilateral adrenalectomy and implantation of cerebral electrodes. Continuous electroencephalographic (EEG) recordings were obtained until the appearance of the first paroxysmal electrical discharges, which was considered to be the first indicator of the toxic effects of hyperbaric oxygen. A statistically significant change in excitability of the cortex to oxygen toxicity from 2 to 22 d following adrenalectomy was shown. Comparison of the sensitivity of the normal and adrenalectomized rats to HOP 2 d after the operation showed significant resistance of adrenalectomized rats at this time. This resistance disappeared gradually, when compared with normal rats, and cortical susceptibility increased significantly 22 d after adrenalectomy. The possible disturbances responsible for the changes in excitability of the cortex to HOP in adrenalectomized rats are discussed.

Adrenalectomy↗