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Biomedical subjects

J Engel

Publications and source records attributed to J Engel.

At least 541 records · Page 30Linked to original sources
PubMed1982

Patterns of human local cerebral glucose metabolism during epileptic seizures.

Ictal patterns of local cerebral metabolic rate have been studied in epileptic patients by positron computed tomography with 18F-labeled 2-fluoro-2-deoxy-D-glucose. Partial seizures were associated with activation of anatomic structures unique to each patient studied. Ictal increases and decreases in local cerebral metabolism were observed. Scans performed during generalized convulsions induced by electroshock demonstrated a diffuse ictal increase and postictal decrease in cerebral metabolism. Petit mal absences were associated with a diffuse increase in cerebral metabolic rate. The ictal fluorodeoxyglucose patterns obtained from patients do not resemble autoradiographic patterns obtained from common experimental animal models of epilepsy.

Brain↗
PubMed1982

Interictal cerebral glucose metabolism in partial epilepsy and its relation to EEG changes.

Interictal positron computed tomography (PCT) with 18F-fluorodeoxyglucose was performed on 50 patients with partial seizures disorders. Electroencephalographic (EEG) monitoring was carried out during the metabolic studies using scalp and sphenoidal electrodes in 33 patients and stereotaxically implanted depth electrodes in 17. Four patients in this series had focal abnormalities on x-ray computed tomographic scans, but these were at the site of the presumed epileptogenic lesion in only 2. One or more discrete zones of hypometabolism were identified in 35 patients, and only 1 patient appeared to show focal interictal hypermetabolism. No quantitative relationship could be demonstrated between the degree of focal hypometabolism and either the frequency of interictal EEG spikes of the presence of focal nonepileptiform EEG changes. It was concluded that metabolic and electrophysiological techniques measure different aspects of cerebral dysfunction in seizure disorders. Although interictal PCT in patients with partial epilepsy usually demonstrates zones of hypometabolism this finding, per se, does not reveal the epileptic nature of the abnormality.

Adolescent↗
PubMed1982

Pathological findings underlying focal temporal lobe hypometabolism in partial epilepsy.

Histopathological studies were carried out on temporal lobe tissue from 25 patients with partial complex seizures who were studied by interictal positron computed tomography (PCT) with 18F-fluorodeoxyglucose and subsequently underwent anterior temporal lobe resection. Abnormalities were identified on x-ray computed tomographic scans in 7 patients, but none indicated the site of a pathologically confirmed structural lesion. Hypometabolic zones were observed on PCT scans of 22 patients and corresponded to focal pathological abnormalities in 19 (15 mesial temporal sclerosis, 2 small neoplasms, 1 angioma, 1 heterotopia). In 1 patient with a focally abnormal PCT scan and no pathological changes, the lesion may have been located posterior to the resection. In the remaining 2 patients, the hypometabolic zones later disappeared and may have represented a transient response induced by depth electrode implantation. Three patients with normal PCT scans had no pathological abnormalities in their resected tissue. The degree of relative hypometabolism measured by PCT correlated well with the severity of the pathological lesion, but the size of the hypometabolic zone was generally much larger than the area of pathological involvement. This discrepancy could not be considered an artifact of technique and must represent either structural abnormalities below the resolution of routine histopathological studies (e.g., loss of synapses) or functional inactivation of neuronal elements associated with the epileptogenic lesion.

Adolescent↗
PubMed1982

Comparative localization of epileptic foci in partial epilepsy by PCT and EEG.

One or more interictal positron computed tomograms of 18F-fluorodeoxyglucose were obtained on 50 patients with partial seizure disorders. Ictal as well as interictal electroencephalographic (EEG) data were available for all 50 patients, with scalp, sphenoidal, and depth electrode recordings done on 27 and scalp and sphenoidal recordings alone on 23. Thirty-five patients demonstrated one or more abnormal interictal zones of hypometabolism, while combined EEG studies were localizing for 36. There were considerable disagreements between the location of metabolic deficits and the epileptic focus revealed by individual scalp and depth EEG recorded ictal and interictal epileptiform activity; however, there was good correlation between the site of focal hypometabolism and the epileptic focus determined by the combined results of all electrophysiological studies. When focal hypometabolism and focal nonepileptiform EEG abnormalities (i.e., slow waves and attenuation of fast rhythms) were both present in the same patient, their localization agreed completely. Metabolic and combined electrophysiological techniques both occasionally produced false positive as well as false negative results. When used together, the EEG can confirm that a hypometabolic zone is epileptogenic, while FDG scans may indicate whether an epileptic EEG focus represents a lesion or propagation from a distant site.

Adolescent↗
PubMed1982

Recurrent volar carpal perilunate subluxation.

Recurrent volar carpal perilunate subluxation (RVCPS) is a rare injury (Linschied 1972). Reviewing the literature we found only 5 reported cases of this condition. Four of them were due to congenital ligamentous laxity, two described by Suturo (1946), and the rest by Linschied and Dobyns (1972). Stark reported on a post traumatic case (Stark 1970). The purpose of this paper is to present an additional case of post traumatic RVCPS.

Adult↗
PubMed1982

Effects of GABAergic agonists and antagonists on various ethanol-induced behavioral changes.

The interaction between ethanol and various GABAergic drugs (muscimol, bicuculline, picrotoxin) with regard to their effects on locomotor activity, drug-induced sleep, body temperature, and convulsions was studied. It was demonstrated that the GABA receptor agonist muscimol potentiated the sedative properties of ethanol, while the opposite effect, a reduction of ethanol-produced sedation, was seen upon administration of the GABA receptor blocking agent picrotoxin. Consequently, the results from the present series of experiments indicate that ethanol enhances central GABAergic activity.

Animals↗
PubMed1982

The effect of chronic ethanol administration of high affinity 3H-nicotinic binding in rat brain.

The effect of chronic ethanol administration on high affinity 3H-nicotinic binding rat brain was investigated. Chronic ethanol administration for 5 months included a significant decrease in the number of specific nicotinic binding sites in the hippocampus, whereas a significantly increase in the number of nicotinic binding sites both in the hypothalamus and in the thalamus was found. Similar effects were observed both after administration of a lower concentration (8% W/V) ethanol and a higher concentration (16% W/V) indicating that the duration of the administration seems to be of importance for the biochemical changes observed.

Animals↗
PubMed1982

Dissociation of C1 and concentration dependence of its activation kinetics.

The activation of the zymogen C1s to the enzyme C1s in the human C1 complex [C1q(c1rC1s)2] was studied as a function of the concentrations of (C1rC1s)2 and C1q which were saturated with oligomers of rabbit IgG. A large concentration dependence of the sigmoidal kinetics was observed in the 2-180 nM concentration range. This was explained by association-dissociation equilibria between the antibody-saturated C1q and various forms of the (C1rC1s)2 complex (unactivated to activated). The establishment of these equilibria (binding constant 2 x 10(7) M-1) was assumed to be fast as compared to the rates of the activation steps (rate constants 10(-3) and 10(-2) sec-1 at 30 degrees C). The fast re-equilibration of the C1 complex explains the finding that small amounts of antibody-saturated C1q catalysed the activation of large amounts of C1s. The interpretation of the kinetic results was supported by a direct demonstration of the dissociation of C1 into C1q and (C1rC1s)2 by analytical and density gradient centrifugation. No difference was found between the rates of activation and the dissociation properties of reconstituted C1 and C1 isolated from serum.

Centrifugation, Density Gradient↗
PubMed1982

Haemophiliac hands--a three year follow-up study.

The total absence of literature regarding the affects of haemophilia on the hand prompted this three year study at the Israel National Haemophilia Centre. The hands of all haemophiliacs were examined and X-rayed at the time of their annual check-up. Apart from a number of established Volkmann's contractures in elderly patients and multiple bone cysts of the carpus, surprisingly little pathology was found. When considering the extensive damage done to the musculoskeletal system by this haemarthritic pathogenesis it is astounding how the hand, with its multiple small joints, constant movement and trauma, escapes significant damage.

Adult↗
PubMed1982

Possible fatigue fracture of the pisiform bone in volleyball players.

Volleyball players commonly complain of pain in the hypothenar area. Fatigue fracture of the pisiform bone is suggested as a cause of this sport incapacity. The diagnostic importance of oblique and axial X-ray views of the Wrist is demonstrated. Early treatment by immobilization for 6 weeks usually results in complete functional recovery.

Adult↗
PubMed1982

Increased salsolinol levels in rat striatum and limbic forebrain following chronic ethanol treatment.

Endogenous levels of salsolinol and its methylated metabolite were measured by combined gas chromatography and mass spectrometry in rats chronically exposed to ethanol for 150 days. The chronic ethanol administration produced a significant increase of salsolinol concentrations in dopamine-rich brain areas, e.g., the striatum and the limbic forebrain. A negative correlation was observed between plasma ethanol concentration and the level of salsolinol in the brain. A possible role for salsolinol in the regulation of ethanol drinking and/or in the development of ethanol dependence is discussed.

Alcoholism↗
PubMed1982

Changes in intelligence following temporal lobectomy: relationship to EEG activity, seizure relief, and pathology.

Pre- and posttemporal lobectomy measures of intelligence and memory in 36 patients with medically refractory complex partial seizures were compared with (1) various aspects of presurgical ictal and interictal EEG activity derived from surface and deep electrodes, (2) postlobectomy seizure relief, and (3) pathological findings in the resected lobe. With respect to interictal EEG data, bilaterally synchronous surface spikes (accompanied or unaccompanied by simultaneous deep spikes) and sharp waves were significantly correlated with lower prelobectomy intelligence scores and a drop in these scores following lobectomy. With respect to ictal EEG data, bilaterally synchronous and multifocal onsets were significantly correlated with a postlobectomy drop in intelligence scores. Patients with poor postlobectomy seizure relief tended to have lower presurgical intelligence scores and a drop in intelligence scores following lobectomy. The patients most likely to show a postlobectomy drop in intelligence were those demonstrating some combination of poor seizure relief, an absence of pathology in the resected specimen, or EEG signs indicative of poor seizure relief. Postlobectomy changes in intellectual status are therefore not necessarily exclusively attributable to the amount of postlobectomy seizure relief experienced by these patients, but might be due to a combination of factors.

Adult↗