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Biomedical subjects

M Seino

Publications and source records attributed to M Seino.

At least 37 records · Page 2Linked to original sources
PubMed1995

Wavelength specificity of photoparoxysmal responses in idiopathic generalized epilepsy.

Using optic filters, we analyzed the wave-length specificity of photoparoxysmal responses (PPR) in photosensitive patients with idiopathic generalized epilepsy (IGE). We specified the wavelength spectrum approximately 700 nm (660-720 nm) as the only visible spectrum essential for eliciting PPR in some normal trichromat IGE patients and showed that any flashing lights containing this essential wavelength spectrum could elicit PPR independent of the number of stimulated cones. Absorption of the wavelength spectrum approximately 700 nm by optic filters eliminated PPR in normal trichromat IGE patients. In an IGE patient with deuteranomaly, intermittent flashing lights containing a part of the wavelength spectrum from 580 to 700 nm elicited PPR. These data suggest a new interpretation of wavelength specificity of PPR: Flashing lights containing the wavelength spectrum that does not produce antagonistic cone interactions at the level of retinal ganglion cells can elicit PPR in some photosensitive IGE patients.

Adolescent↗
PubMed1995

Self-induced photogenic seizures in a child with severe myoclonic epilepsy in infancy: optical investigations and treatments.

In a 2-year-old patient with severe myoclonic epilepsy in infancy, we studied self-induced photogenic seizures using optical filters and blue-tinted contact lenses. The patient induced absences and/or myoclonic jerks by two kinds of behaviors: flickering hand movement (FHM) and forced eye closure (FEC). The placebo inhibitory effect on FHM by a blank goggle frame indicated that acquisition of learning affected the frequency of FHMs per se. Optical studies suggested that the degree of absorption from approximately 600-700 nm might determine the inhibitory effect of filters on FHM. Investigations using contact lenses showed that blue-tinted lenses gradually reduced photosensitivity and inhibited FHMs.

Child, Preschool↗
PubMed1995

Nonphotosensitive video game-induced partial seizures.

We report a 9-year-old boy with a ring 20 chromosome anomaly whose complex partial seizures (CPS), presumably of frontal lobe origin, were often induced by playing video games. Neither photosensitivity nor pattern sensitivity was observed. An intensive video-EEG investigation showed that video games as well as mental calculation elicited rhythmic runs of bilateral high-voltage slow waves, which eventually evolved into ictal discharges. This case suggests that higher brain functions can be involved in seizure induction.

Brain↗
PubMed1995

Can absence status epilepticus be of frontal lobe origin?

Five women with an unclassifiable nonconvulsive status epilepticus (NCSE) characterized by young age at onset, prolonged confusions, focal motor seizures, and both generalized spike-and-wave discharges and focal epileptic discharges on the EEG were studied with video-EEG monitoring. Electrographically, the NCSE originated from the left frontal lobe in 4 patients, and the left hemisphere with multifocal seizure discharges in 1 patient. Focal motor seizures seemed to originate from the left hemisphere in all 5 patients, particularly from its anterior part in 3 of them. Results show that the NCSE is complex partial status epilepticus of frontal lobe origin electroclinically mimicking absence status epilepticus once it reaches a full-blown phase.

Adult↗
PubMed1995

Recombinant human erythropoietin stimulates tubular reabsorption of sodium in anesthetized rabbits.

To determine whether recombinant human erythropoietin (rHuEPO) exerts a direct vasoconstrictive effect on renal arteries or affects renal function, we measured renal hemodynamics and renal function during a 30-min intrarenal infusion of rHuEPO in anesthetized rabbits without renal failure. Intrarenal infusion of rHuEPO at a rate of 100 U/min did not alter mean arterial pressure, renal blood flow, or renal vascular resistance, as compared with controls treated with vehicle. There were no significant rHuEPO-associated changes in glomerular filtration rate, filtration fraction, or arterial hematocrit. However, urine volume, urinary excretion of sodium and potassium, and fractional sodium excretion were significantly reduced by intrarenal infusion of rHuEPO. These observations indicate that rHuEPO has no direct effects on mean arterial pressure or renal hemodynamics, but that it stimulates net tubular sodium reabsorption, and reduces urine volume and urinary excretion of sodium and potassium in anesthetized rabbits without renal failure.

Animals↗
PubMed1995

[The practical benefits of magnetoencephalography in comparison with electroencephalography in a patient with epilepsia partialis continua].

A concurrent recording of electroencephalography (EEG), magnetoencephalography (MEG) and electromyography (EMG) was carried out in a patient with epilepsia partialis continua. He had continuous clonic jerks in his right hand and fingers. The EMG electrodes were placed on the thumb of his right hand. We observed numerous MEG spikes in the left central region and about half of them were accompanied by EMG potentials with a latency of about 20 msec. The EEG spikes appeared less frequently, had low amplitudes, and had unclear morphologies and further, no clear association with EMG potentials. MEG spikes were more reliably associated with individual jerks, exemplified by EMG potentials, than the EEG spikes. The MEG spikes were sharper than EEG spikes and were about 20 msec wide. The intracranial dipole localization of the MEG spikes was estimated by overlaying the calculated generator sites on magnetic resonance images. It was found that the spikes converged along a line, presumably the central sulcus. The practical benefits of the MEG as a diagnostic tool in epilepsy are illustrated.

Adult↗
PubMed1994

Bromide, in the therapeutic concentration, enhances GABA-activated currents in cultured neurons of rat cerebral cortex.

We investigated the effect of bromide on gamma-aminobutyric acid (GABA)-activated currents in cultured cerebral neurons of the rat, employing whole-cell voltage- and current-clamp techniques. Application of 100 microM GABA elicited currents whose reversal potential was 0 mV with equal concentrations of chloride in both pipette and bath solutions and more negative than -60 mV with 159 mM chloride extracellularly and 4 mM chloride inside. Bicuculline blocked the currents. These findings showed that the currents were composed of chloride flux through GABAA receptor-coupled channels. Reversal potential revealed a permeability ratio of bromide with respect to chloride (PBr/PCl) of 1.51. When 100 microM GABA was applied with the extracellular solution containing 140 mM bromide and 19 mM chloride, the currents were enhanced 2.00- and 1.91-fold at the holding potentials of -20 mV and 0 mV, respectively. Extracellular solutions containing various concentrations of bromide substituted for the same amount of chloride were applied with 100 microM GABA. The therapeutic concentration of 10 mM and 20 mM bromide enhanced the currents 1.28- and 1.36-fold of the control currents at the holding potential of -20 mV, respectively. Under current-clamp recording, a larger hyperpolarization was obtained by the application of GABA with a 140 mM bromide-containing solution. These findings suggest that bromide potentiated GABA-activated currents at the therapeutic concentrations ranging from 10 mM to 20 mM, causing the larger GABA-induced hyperpolarization. It is postulated that the antiepileptic effect of bromide might occur through the potentiation of inhibitory postsynaptic potentials elicited by GABA.

Animals↗
PubMed1994

Improvement of quality-of-life following resective surgery for temporal lobe epilepsy: results of patient and family assessments.

In order to evaluate the quality-of-life (QOL) of epilepsy surgery patients, we surveyed patients' degree of life satisfaction and their families' degree of satisfaction with patient's status in a range of domains both pre- and post-operatively. Of 100 patient-family sets of surveys that were mailed out, 93 were completed and returned from patients and 91 from their families. All patients surveyed had temporal lobe epilepsy and had been followed for longer than 2 years after resective surgery. Patients and their families rated overall QOL as having markedly improved following surgery. However, they rated social domains of QOL, including role activities, financial status, and social and family relationships as having improved relatively little. Despite freedom from seizures, a few patients' families were dissatisfied with the patients' post-operative status, primarily for psychosocial reasons. Patients operated on at a later age reported little gains in life satisfaction following surgery. This study supports the conclusion that surgical intervention should occur before patients are subjected to the psychological conflicts and social handicaps associated with chronic intractable epilepsy.

Adaptation, Psychological↗
PubMed1994

A comment on the efficacy of valproate in the treatment of partial seizures.

Discrepancies in the findings of studies sponsored by the Department of Veterans Affairs (VA) in the United States and the Medical Research Council (MRC) in the United Kingdom concerning the efficacy of valproate (VPA) in controlling simple or complex partial seizures, particularly those without secondarily generalized seizures, were reviewed. It was noted that the two studies differed with respect to their subjects' pretreatment seizure frequency. The frequency of complex partial seizures before treatment was obviously greater in the VA study, where carbamazepine (CBZ) provided better seizure control than VPA. Based on other comparative and non-comparative studies as well as the author's over 20 years of experience in the use of VPA in a tertiary epilepsy clinic, it is suggested that although VPA may be effective in controlling both the secondarily generalized seizures of symptomatic localization-related epilepsies and the generalized tonic-clonic seizures of idiopathic and, if not always, symptomatic generalized epilepsies, the efficacy of VPA in controlling simple or complex partial seizures is likely limited to patients with infrequent seizures.

Carbamazepine↗
PubMed1993

Human somatostatin receptor genes: localization to human chromosomes 14, 17, and 22 and identification of simple tandem repeat polymorphisms.

The genes encoding three different human somatostatin receptor subtypes, designated SSTR1, SSTR2, and SSTR3, were mapped to chromosomes 14, 17, and 22, respectively, by analyzing their segregation in a panel of reduced human-hamster somatic cell hybrids. These assignments were confirmed independently using fluorescence in situ hybridization to metaphase chromosomes and the genes were further localized to 14q13, 17q24, and 22q13.1, respectively. Highly informative simple tandem repeat DNA polymorphisms were identified in SSTR1 and SSTR2.

Base Sequence↗
PubMed1993

Localizing value of seizure manifestations of temporal lobe epilepsies and the consequence of analyzing their sequential appearance.

We investigated the localizing and lateralizing value of principal seizure manifestations in temporal lobe epilepsies (signal symptoms, oroalimentary automatisms, somatomotor manifestations, unilateral dystonic posturing, ictal speech, motionless stare) of 223 complex partial seizures in 50 patients. All the patients had invasive long-term monitoring with the combined implantation of intracerebral electrodes in and subdural electrodes on the bilateral temporal lobes. Postoperative freedom from seizures was ascertained for longer than one year. We found that 35 patients had amygdalohippocampal seizures and 15 had lateral temporal seizures. The value of the manifestations was established in relation to the site and side of seizure origin and to the progression of seizure discharges within the unilateral temporal lobe or to the contralateral cerebral hemisphere. Several signs among the manifestations were found to be reliable in predicting the site or side of the temporal lobe seizure focus. We emphasized the importance of investigating sequential changes of seizure manifestations in relation to ictal EEG findings by means of simultaneous recording.

Amygdala↗
PubMed1993

Drop attacks and epileptic syndromes.

1. In addition to 4 types of drop attacks previously described by Ikeno et al., we could ascertain the falls of the myoclonic-tonic type in genuine drop attacks. The genuine drop attacks were seen in Lennox-Gastaut syndrome, epilepsy with myoclonic-astatic seizures and other symptomatic generalized epilepsies, and never in partial epilepsies. 2. None of the patients with partial epilepsy revealed genuine drop attacks as defined. Their drop attacks were slower (i.e. the falls were completed in more than 1 sec.). 3. In the 15 patients with Lennox-Gastaut syndrome, the drop attacks disappeared in 8 patients, and decreased in severity and frequency in 3 patients. Namely, the intractability of drop attacks in two-thirds of the children decreased as the patients grew older. This finding must be taken into consideration when patients with drop attacks are considered for surgical treatment of their epilepsy.

Adolescent↗