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Biomedical subjects

R Morawetz

Publications and source records attributed to R Morawetz.

44 records · Page 3Linked to original sources
PubMed1987

Brain tumors presenting as a seizure disorder in infants.

Seizures occur in 25% to 40% of children with supratentorial tumors and are the presenting complaint in 10% to 15%. However, when divided by age, only 2% of children with seizures as the presenting complaint of brain tumors were less than 1 year of age. Three children, ranging in age from 20 days to 7 months and seen within the past 2 years, form the basis of this report. The presenting complaint in all children was seizures. Computed tomographic (CT) scan was indicated in all children because of intractability to anticonvulsant drug therapy (one patient) and focal electroencephalographic (EEG) abnormality with clinical evidence of complex partial seizure activity (two patients). CT scan showed a contrast-enhancing mass in the medial temporal lobe in all patients. At surgery, a temporal lobe tumor was found and resected in all children. Histopathologic examination revealed a ganglioglioma, a fibrillary astrocytoma, and an anaplastic astrocytoma. All children did well postoperatively and are seizure free to date. Our experience suggests that supratentorial tumors should be considered as a cause of intractable and/or focal seizures in children under 1 year of age, and that such tumors should be attacked aggressively neurosurgically. Our experience is also in agreement with that of Tadmor et al, who have suggested that with the advent of CT scanning supratentorial tumors in this age group have been found to be more common than previously realized.

Astrocytoma↗
PubMed1983

Transient focal ischemia in subhuman primates. Neuronal injury as a function of local cerebral blood flow.

Unilateral, transient (30, 60, and 120 minutes (min)) middle-cerebral-artery (MCA) occlusion was induced via transorbital craniotomy in 11 waking subhuman primates. Local cerebral blood flow (LCBF) was calculated from hydrogen clearance curves obtained through the use of intracerebral platinum microelectrodes. Unilateral MCA occlusion decreased LCBF in the territory of the ipsilateral MCA. Within minutes of the arterial occlusion all monkeys developed contralateral neurologic deficits that began disappearing three hours (h) after reopening the MCA. Regional ischemia, followed by 24 h of reperfusion, produced varying degrees of tissue vacuolation which correlated (r = 0.60, p less than 0.01, n = 49) with the percent reduction in LCBF multiplied by the occlusion time. Neurons were classified according to the structural features of their perikaryon. A plot of neuron types versus percent vacuolation suggested that normal neurons become increasingly scalloped under increasingly severe ischemic conditions. The number of scalloped neurons decreased precipitously in areas of marked sponginess coincident with the appearance of irreversibly damaged neurons. Local tissue edema values exceeding 30% correlated with irreversible injury to all neurons in the same area. Regional cerebral ischemia of increasing severity was acompanied by increasing numbers of lethally injured neurons.

Animals↗
PubMed1979

Familial arteriovenous malformation.

A family is reported in which 3 siblings, 2 with the same and the third with a different father, were demonstrated to have cerebral arteriovenous malformations.

Adolescent↗
PubMedDate not supplied

Effects of ischemia on the oxygen diffusion coefficients in the brain cortex (studies on Macaca irus).

In this series of experiments changes in oxygen diffusion coefficients were measured in waking primates undergoing focal middle cerebral artery ischemia; Ligation of the middle cerebral artery followed by a decrease of the oxygen diffusion coefficient in the areas supplied by that vessel to levels ten to twenty per cent below normal by twenty-five minutes following onset of ischemia. Following release and re-perfusion diffusion coefficient gradually increases and reaches a super normal peak value three hours after release of ligation. This is followed by a gradual reduction in diffusion coefficient with stabilization at preocclusion levels. In the three experiments described these changes following re-perfusion corresponded with clinical improvement of the neurological status of the monkeys;

Animals↗
PubMedDate not supplied

Electroencephalographic correlations of extracranial and epidural electrodes in temporal lobe epilepsy.

Thirty patients with medically intractable complex partial seizures of temporal lobe origin, but no structural abnormalities on neuroradiologic investigations, had both extracranial (scalp) and epidural EEG recordings. Fifteen patients (50%) had localized, unilateral, ictal, scalp EEGs, but one of these had bilateral independent temporal seizure onset according to epidural recordings. Of the 15 patients in whom scalp EEGs were non-localizing, 12 had well-localized epidural ictal EEGs, and 3 had multifocal or bilateral independent temporal ictal recordings. Epidural recordings provide information for determination of site of onset of temporal lobe seizures in selected patients.

Adult↗
PubMedDate not supplied

Antiepileptic drug treatment after temporal lobe epilepsy surgery: a randomized study comparing carbamazepine and polytherapy.

Temporal lobectomy is an effective treatment in selected patients with medically intractable temporal lobe epilepsy (TLE). Postoperative antiepileptic drug (AED) treatment guidelines have not been established, and patients are often treated with polytherapy postoperatively. We prospectively randomized 40 patients undergoing temporal lobectomy to monotherapy with carbamazepine (CBZ, 20) or to continuation of their presurgical polytherapy (20) to assess the efficacy and safety of each regimen during the first year after operation. No significant differences between groups were noted with respect to seizure recurrence rate and type or time of recurrence. Patients in the polytherapy group had a 30% incidence of drug-related side effects as compared with only 10% in the CBZ group. These results suggest that after temporal lobectomy for intractable epilepsy, patients can be safely treated with CBZ monotherapy and that treatment with multiple AEDs is not necessary.

Adolescent↗