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Biomedical subjects

T Mimaki

Publications and source records attributed to T Mimaki.

At least 37 records · Page 2Linked to original sources
PubMed1990

Changes in cerebral white matter in a case of congenital muscular dystrophy (non-Fukuyama type).

A 3-year-old Japanese boy with congenital muscular dystrophy (CMD) and normal intelligence is presented. He had not learned to crawl, shuffled on his bottom, and could not walk. At 7 months, his CT-scan had showed periventricular low density and mild ventricular dilatation, and spike or sharp wave discharges were seen on EEG. At three years of age, his CT-scan revealed wide-spread hypodensity in the cerebral white matter, EEG showed multifocal discharges, and MRI showed abnormal high density area in the cerebrum on spin echo image. These findings suggest the existence of an intermediate form of CMD between the Fukuyama type of CMD and the classical occidental type of CMD. The combination of repeated CT and MRI scans seems necessary for the evaluation of CNS abnormalities in CMD.

Biopsy↗
PubMed1990

Auditory brain stem response and electrically elicited blink reflex in handicapped children.

The auditory brain stem response and the blink reflex were studied in 35 handicapped children in order to evaluate brain stem function. The auditory brain stem response and the blink reflex were abnormal in 20 and 16 cases, respectively. Of these, 14 had both auditory brain stem response and blink reflex abnormalities. The prevalence of auditory brain stem response and blink reflex abnormalities was high in severely handicapped children with difficulty in chewing or swallowing. The blink reflex was abnormal in four of 32 sides with a normal auditory brain stem response and 15 of 23 sides with an abnormal auditory brain stem response threshold, which reflects hearing loss or brain stem dysfunction. We conclude that the combined application of these two noninvasive tests is useful not only to delineate the extent of brain stem lesions but also to determine whether or not patients with an abnormal auditory brain stem response threshold have brain stem dysfunction.

Acoustic Stimulation↗
PubMed1990

Interaction of zonisamide with benzodiazepine and GABA receptors in rat brain.

The effects of zonisamide on [3H]flunitrazepam binding and [3H]muscimol binding were studied in Sprague-Dawley rat brain. Specific [3H]flunitrazepam bound was decreased to 64.6 +/- 5.6% (mean +/- SD, n = 5, p < 0.002) and 91.9 +/- 4.0% (p < 0.005) by the addition of 10(-3) M and 10(-4) M zonisamide, respectively. Scatchard plot analysis of [3H]flunitrazepam binding with 10(-3) M of zonisamide revealed an increased Kd value with no change in Bmax. No inhibitory effect of zonisamide was seen on the enhancement of specific [3H]flunitrazepam binding by GABA. As for the effects on GABA receptors, specific [3H]muscimol bound was decreased to 27.7 +/- 10.4% (mean +/- SD, n = 4, p < 0.005) and 68.3 +/- 3.7% (mean +/- SD, n = 4, p < 0.005) by the addition of 10(-3) M and 10(-4) M zonisamide, respectively. Since therapeutic serum level of zonisamide are around 10(-4) M, these results suggest that zonisamide neuropharmacologically interacts with the GABA/benzodiazepine receptor ionophore complex in a manner similar to phenytoin.

Animals↗
PubMed1990

[3H]zonisamide binding in rat brain.

We previously reported that zonisamide inhibits both [3H]flunitrazepam and [3H]muscimol binding in rat brain. In the present study, [3H]zonisamide was found to bind in a saturable fashion to the crude synaptosomal fraction of whole rat brain. Linear regression analysis of the binding data in the Scatchard plot indicated a Kd of 90 nM, and a maximal binding capacity of 1.40 x 10(3) fmol/mg protein. Displacement studies revealed an inhibitory effect of clonazepam and an enhancement effect of GABA on specific [3H]zonisamide binding. These results suggest that specific [3H]zonisamide binding sites may have a tight correlationship with benzodiazepine receptors in rat brain.

Animals↗
PubMed1989

Prognostic value of electrically elicited blink reflex in neonates.

The electrically elicited blink reflex (BR) was evaluated in 80 normal neonates and 12 neonates with neurologic abnormalities. In normal subjects, R1 and bilateral R2 responses were elicited both while awake and in a quiet sleep state. Whereas the R1 response was consistently elicited in the active sleep state, as well as while awake, the ipsilateral R2 response was markedly suppressed and the contralateral R2 response was almost absent. The BR in neonates with neurologic abnormalities showed the following variable results: normal, prolonged latency, or suppressed response at initial recording. Abnormal BRs were detected in most neonates with respiratory or sucking problems. While neonates in whom a suppressed response or prolonged latency persisted for over three months had a poor prognosis, those with normal BRs or early correction of the BR abnormality had almost normal development. The BR appears to be useful not only to evaluate brain-stem function in the neonatal period but also to predict subsequent outcome.

Blinking↗
PubMed1989

Cutis laxa with ultrastructural abnormalities of elastic fiber.

A case of a congenital, autosomal recessive form of generalized cutis laxa is reported. The patient was a 27-month-old boy with generalized flaccid skin and short stature. Radiologic examination revealed that the age of the bones of the wrist was compatible with a chronologic age of only 1 year. Elastic fibers were diminished throughout the dermis, and results of electron microscopic study showed globular and unstained elastin and relatively large amounts of the microfibrillar components of elastic fibers.

Biopsy↗
PubMed1989

EEG and CT abnormalities in xeroderma pigmentosum.

Xeroderma pigmentosum associated with neurological abnormalities is a less familiar neurocutaneous disorder. In this report, 35 patients with group A xeroderma pigmentosum were assessed for neurological complications. Of these, 17 showed microcephaly and 24 mental retardation. Of 25 patients over 7 years of age, 22 had sensorineural deafness and 12 showed spinocerebellar signs such as nystagmus, dysarthria, tremor and ataxia, while none below 7 years of age had such neurological complications. Thirty-five EEG studies were performed on 29 patients, and 15 showed intermittent spindles of grouped theta waves with abnormal slow background activity and a poorly developed alpha rhythm, suggesting immature brain development or a regression from normal brain function in many areas including the diencephalon. Twenty-six patients were examined by cranial CT scan, of whom 20 showed abnormal CT findings such as ventricular dilatation, diffuse cortical atrophy, and marked thickening of the calvarial bones. The incidence of abnormal EEG and CT findings increased with advancing age in accordance with the development of neurological complications in the CNS, thus suggesting a chronic progressive degenerative disease.

Adolescent↗
PubMed1989

Vitamin E status in pediatric patients receiving antiepileptic drugs.

Decreased vitamin E levels have been reported in epileptic children receiving antiepileptic drugs (AED). In order to investigate the tocopherol status of patients receiving AED, the alpha-, beta, gamma- and delta-tocopherol concentrations were each determined in 447 patients' serum samples using a high-performance liquid chromatographic method. In pediatric patient samples (n = 244, aged 1-16 years), there was a negative relationship (p less than 0.02; r = -0.153) between age and alpha-tocopherol levels, while there was a positive relationship (p less than 0.05; r = 0.142) between age and gamma-tocopherol levels. The mean (+/- SD) alpha-tocopherol levels (0.73 +/- 0.23 mg/dl) in the older children (n = 166, aged 7-16 years) were significantly lower (p less than 0.05) than the levels (0.83 +/- 0.23 mg/dl) found in the younger children (n = 78, aged under 7 years). Administration of alpha-tocopherol acetate, 3 mg/kg/day to 8 children and 5 mg/kg/day to 4 children, increased alpha- and total tocopherol levels (p less than 0.01 for both), while gamma-tocopherol levels and serum lipid peroxide levels were decreased (p less than 0.01 for both). In 203 epileptic patient samples (over 16 years of age), the mean alpha-tocopherol level (0.92 +/- 0.28 mg/dl) tended to be lower (p less than 0.1) than in 22 healthy adult controls (1.01 +/- 0.26 mg/dl).

Adolescent↗
PubMed1989

[Ultrasonic Doppler assessment of hemodynamics in extra-intracranial arterial anastomosis in children with Moyamoya disease].

Recently the extra-intracranial (EC/IC) arterial bypass operation has been introduced in the treatment of Moyamoya disease and excellent postoperative outcomes have been reported. To assess the cerebral hemodynamic changes after the bypass surgery, ultrasonic Doppler flowmetry was performed in 10 children with Moyamoya disease. Their surgical treatments included superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis or encephalo-duro-arterio-synangiosis. The flow velocity and pattern of the major cerebral arteries and STAs, the donor artery of the bypass, were studied both before and after the operation. The results of Doppler flowmetry were compared with clinical symptoms and angiographical findings. Though the Doppler sonography of the major cerebral arteries showed little change, the flow velocity of the STAs revealed a pronounced and rapid increase after the bypass surgery. The flow pattern of the STAs, which was of the external carotid type preoperatively, changed to the internal carotid type postoperatively. These ultrasonic Doppler findings were thought to be due to a decrease in the peripheral vascular resistance, and suggested a good patency of the bypass arteries. These results of the Doppler flowmetry were in good agreement with clinical and EEG improvement and the findings of the postoperative cerebral angiography. It is suggested that ultrasonic Doppler flowmetry is a noninvasive and reliable method of assessing the function of the EC/IC bypass in children with Moyamoya disease.

Adolescent↗
PubMed1989

[Studies on intraoperative cardiac mapping].

Precise determination of the arrhythmogenic area by the intraoperative cardiac mapping procedure is a prerequisite to successful surgical therapy for tachyarrhythmias. Because of the limitation of time during operation, mapping should be performed precisely and quickly. For this purpose we have developed and used an on-line portable minicomputer system (modified HPM-6500; Fukuda Denshi Co., Ltd.). A ventricular epicardial excitation sequence map is acquired by measuring the conduction time difference for 51 predetermined points on the whole ventricular surface. The measured data are instantaneously digitized and computed to be displayed as an isochornous map in real time basis. Similar program is available for atrial excitation map. With this system it takes only about ten minutes to get an epicardial isochornous map. Recently a multi-channel signal-processing unit has been incorporated in the HPM-6500. With the use of a sock electrode or a card electrode, a map can be obtained on a few cardiac contractions. Multi-point simultaneous mapping has been proved to be especially important to get a VT isochornous map, for induced VTs during operation are usually unstable and transient.

Arrhythmias, Cardiac↗
PubMed1988

Chiari I malformation with quadriplegia and respiratory disturbance in an infant.

Chiari I malformation consists of variable downward displacement of the cerebellar tonsils. Quadriplegia, respiratory disturbance and pain are common in Chiari I malformation in adults. However, there are no reports of this syndrome in early childhood. We report the case of a 9-month-old girl with Chiari I malformation who had quadriplegia with muscle weakness and who developed respiratory disturbance as an early symptom. The causes of the symptoms of Chiari I malformation are discussed. The use of MRI is proposed as a more useful diagnostic technique than myelography for these patients since MRI is less likely to aggravate the respiratory disturbance.

Age Factors↗
PubMed1988

Intravenous injection of flunitrazepam for status epilepticus in children--two case reports.

Two cases of status epilepticus are reported, whose seizures responded well to the injection of flunitrazepam. One patient had generalized tonic clonic seizures and the other had partial seizures. The improvement of their condition was confirmed by both clinical and electroencephalographic examinations. There were no serious side effects observed. Flunitrazepam might have a potential efficacy for the treatment of status epilepticus of both generalized and partial seizures.

Electroencephalography↗
PubMed1988

Delayed bone development in epileptic children assessed by microdensitometer.

Bone development of metacarpal bones was assessed by microdensitometer analysis of hand X-rays from 101 epileptic outpatients. Most of the patients were treated with two or three anticonvulsant drugs; however, 27 patients were treated with only one. A significantly larger number of patients showed a delay in bone development of 2 or more years when compared with either handicapped or normal control children. In epileptic children, physical activity and the duration of anticonvulsant therapy were correlated with bone development. Patients with delayed bone development had reduced levels of serum 25-OH-D (p less than 0.005) and elevated levels of 1,25-(OH)2D (p less than 0.01). Microdensitometer analysis of metacarpal bone radiographs is useful for detecting mild impairment of bone in groups of epileptic children.

Adolescent↗