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Biomedical subjects

J A Wada

Publications and source records attributed to J A Wada.

At least 73 records · Page 4Linked to original sources
PubMed1985

Differential diagnosis of epilepsy.

Elements relevant to differential diagnosis between epileptic seizure and non-epileptic seizure as a consequence of syncope, cardiac arrhythmia or pseudoepilepsy are reviewed and discussed. Our experience with long-term monitoring of closed circuit TV-EEG of 136 medically refractory seizure patients showed that (a) about 19% have pseudoepileptic seizures, (b) only 36% of those verified pseudoepileptic seizure patients had epileptic seizures as well, and (c) 77% of pseudoepileptic seizures mimicked aspects of complex partial seizures. Pseudoepileptic seizures were not suspected by referring clinicians in the majority of cases, while a small but significant number of patients with verified complex partial seizures were suspected of having pseudoepileptic seizures. Failure to identify these non-epileptic seizures has serious medical and psychosocial implications and, therefore, astute clinical judgment is necessary in the differential diagnosis of epilepsy. Despite some technical limitations inherent in its current practice, the judicious use of long-term monitoring significantly enhances the quality of such judgment upon which the development of a management approach most meaningful to those medically refractory patients and society depends.

Adolescent↗
PubMed1984

Reversible suppression of amygdaloid kindled convulsion following unilateral gabaculine injection into the substantia innominata.

Amygdaloid kindled generalized convulsion was reversibly blocked despite continued afterdischarge generation by amygdaloid stimulation for about 60 h following intracerebral administration of gabaculine, a GABA-transaminase inhibitor, into the substantia innominata (SI) ipsilateral to the side of amygdaloid kindling. It is suggested that the SI plays an important role in convulsive seizure generalization of amygdaloid origin.

Action Potentials↗
PubMed1984

Amygdaloid kindling in Papio cynocephalus and subsequent recurrent spontaneous seizures.

Three baboons, Papio cynocephalus, (two photosensitive and one nonphotosensitive) were subjected to amygdaloid kindling. Electroclinical profile of seizure development-developed seizure compares very favourably to that described in photosensitive baboons, Papio papio, with rapid seizure progression and ultimate emergence of Stage 5 bisymmetrical and bisynchronous generalized convulsive state. In addition, one baboon developed spontaneous recurrent seizures which were identical to the kindled Stage 5 seizure. It is concluded that the state of exceptional seizure susceptibility observed in Papio papio is shared by Papio cynocephalus, although photosensitivity and kindled generalized convulsion appear to be independent variables.

Amygdala↗
PubMed1984

A study of somatostatin receptors in amygdaloid-kindled rat brain.

Kindling is an animal model of epilepsy. Previously somatostatin (SRIF) was implicated in seizure activity in the brain. Recently we reported a significant increase in brain SRIF content in the temporal cortices and cortices of kindled rats. Since the interaction between the neurotransmitter and the receptor eventually is responsible for the biological response, the present study was undertaken to examine evidence for the participation of SRIF receptor in the kindled state. In this study we present a procedure for detection of SRIF receptors using radiolabeled (D-Tyr8)-SRIF as a tracer. The present study indicates that in kindled rats there are no differences in the total number or affinity of the binding sites in the temporal cortex and a slight increase in the total number of binding sites in the cortex when compared with controls. These results, in view of our other observations, suggest that in kindled rat brain there may be an increased release of SRIF but no down-regulation of SRIF receptors in temporal cortex and cortex. There appears to be a significant decrease in the number of SRIF receptors in kindled hippocampus. The mechanism by which this occurs remains unclear.

Amygdala↗
PubMed1984

Antiepileptic effects of thyrotropin-releasing hormone and its new derivative, DN-1417, examined in feline amygdaloid kindling preparation.

The comparative antiepileptic effects of the thyrotropin-releasing hormone and its new derivative, gamma-butyrolactone-gamma-carbonyl-L-histidyl-L-prolinamide citrate (DN-1417), were examined in feline amygdaloid kindling preparations. When tested in kindled animals, both agents showed a transient and non-dose-dependent anticonvulsant effect, in addition to raising the generalized convulsive seizure-triggering threshold for a prolonged period of time. Furthermore, DN-1417 exerted a significant effect on postictal events: shortening the electrographic silence, leaving the duration of slow activity intact, while prolonging the period of seizure refractoriness. When tested in kindling animals, DN-1417 showed a significant but non-dose-dependent prophylactic effect on both primary and secondary amygdaloid sites.

Amygdala↗
PubMed1984

Limbic kindling in the forebrain-bisected photosensitive baboon, Papio papio.

When forebrain-bisected photosensitive baboons, Papio papio, were kindled from the amygdala or hippocampus, bilateralization of convulsive seizure proved difficult, and the final stage of bisymmetrical and bisynchronous convulsive seizure unique to this species did not develop despite more than twice the number of kindling stimulations required for its development in nonbisected baboons. At the secondary site amygdala, convulsive seizure development was suppressed. Findings of the present and previous studies suggest that the corpus callosum plays: (a) a major, if not an exclusive, role in convulsive seizure bilateralization ; and (b) a critical role in the development of primarily generalized convulsive seizures unique to this epileptic baboon. Finally, in the absence of the corpus callosum (and the hippocampal commissure) the transhemisphere seizures suppressing effect generated by amygdaloid kindling appears to be mediated through the subcortical pathway which presumably exists in the brainstem.

Amygdala↗
PubMed1983

Profound suppression of kindled seizures by cysteamine: possible role of somatostatin to kindled seizures.

Recently we reported significant increase in immunoreactive somatostatin content in various brain regions of amygdaloid-kindled rats. We report here that acute intraperitoneal administration of cysteamine, an agent reported to deplete brain and gastrointestinal immunoreactive somatostatin content in kindled rats, led to profound suppression of kindled seizures. Purified anti-somatostatin antibody injected intracerebroventricularly also blocked the kindled seizures. The results show that endogenous immunoreactive somatostatin has a role in the development of seizures in amygdaloid kindled rats.

Animals↗
PubMed1983

Changes of immunoreactive somatostatin and beta-endorphin content in rat brain after amygdaloid kindling.

A possible contribution of brain beta-endorphin and somatostatin to the epileptogenicity established by amygdaloid kindling was investigated in rats. Fourteen male rats were chronically implanted with electrodes placed bilaterally into the amygdala. The rats received 1 sec of electrical stimulation to the left amygdala each day. Generalized seizures were observed on average 10 days after initiation of kindling and the electrical stimulation was continued up to twenty-one days. Two months after the completion of the kindling procedure, each kindled and control rat was killed by microwave irradiation and the brains were dissected on ice into thirteen subregions. Each region was homogenized and centrifuged twice in 0.1 N acetic acid. The supernatant extracts were decanted and stored at - 20 degrees C until assay. Immunoreactive beta-endorphin and somatostatin were measured by radioimmunoassays. There were no significant differences in brain beta-endorphin contents between the two groups. In kindled rats, immunoreactive somatostatin was increased significantly in amygdala, sensorimotor, piriform, and entorhinal cortex. The results suggest that changes in somatostatin may be associated with epileptic susceptibility induced by the electrical kindling procedure.

Amygdala↗
PubMed1982

Forebrain bisection and feline amygdaloid kindling.

Callosal (CC) bisection following completion of primary site amygdaloid kindling modified the established generalized electroclinical seizures into lateralized and asymmetrical ones. Secondary site amygdaloid kindling following the bisection showed not only a lack of transhemispheric positive transfer effect but also a significant interference effect which became maximal with complete CC bisection. It is postulated that the transhemispheric positive transfer effect is primary site hemisphere dependent and is mediated via the cropus callosum, whereas the transhemispheric interference effect is secondary site hemisphere dependent and is mediated via the extracallosal route, probably the brainstem. Our findings suggest that the dynamic functional integrity of the corpus callosum, particularly its anterior to midportion, plays a major role in the mechanisms of generalized convulsive seizure of amygdaloid origin by readily enabling either ictal participation of the secondary site hemisphere during primary site kindling or ictal accession of the primary site kindled mechanisms from the contralateral hemisphere during secondary site kindling.

Amygdala↗
PubMed1982

Long-term follow-up after cerebral hemispherectomy: neurophysiologic, radiologic, and psychological findings.

Eight patients were studied 3 to 16 years (mean, 10 years) after cerebral hemispherectomy. Seven have infantile hemiplegia, and one had Sturge-Weber disease. Preoperative assessment included EEG responses to intracarotid drug injections. Postoperative complications occurred in seven patients. The operation was followed by a marked reduction in seizure frequency and improvement in behavior, with little change in intellect or hemiplegia. Neuropsychological assessment performed in four patients showed that they were not aphasic, but nonverbal spatial abilities were poor. CT showed marked shift of the remaining hemisphere in five of six patients scanned.

Adolescent↗
PubMed1981

Neuropsychiatric and electroencephalographic aspects in the diagnosis of complex partial seizures.

The authors review from a psychiatric perspective some of the electroencephalographic techniques that may assist the clinician in diagnosing complex partial seizures (temporal lobe epilepsy). Routine scalp electroencephalograms may not detect temporal lobe EEG abnormalities, leading to the false impression of pseudo or hysterical seizures. Knowledge of the advantages of a sleep recording, specialized EEG electrodes (nasopharyngeal, sphenoidal), and natural or pharmacological activation techniques will increase one's diagnostic acumen. The authors discuss the appropriate use of these methods and their relevance to psychiatry.

Adult↗