Biomedical subjects

Tomohiro Kumada

Publications and source records attributed to Tomohiro Kumada.

6 recordsLinked to original sources

PubMed2006

A neurosphere-derived factor, cystatin C, supports differentiation of ES cells into neural stem cells.

Although embryonic stem (ES) cells are capable of unlimited proliferation and pluripotent differentiation, effective preparation of neural stem cells from ES cells are not achieved. Here, we have directly generated under the coculture with dissociated primary neurosphere cells in serum-free medium and the same effect was observed when ES cells were cultured with conditioned medium of primary neurosphere culture (CMPNC). ES-neural stem cells (NSCs) could proliferate for more than seven times and differentiate into neurons, astrocytes, and oligodendrocytes in vitro and in vivo. The responsible molecule in CMPNC was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, which turned out to be cystatin C. Purified cystatin C in place of the CMPNC could generate ES-NSCs efficiently with self-renewal and multidifferentiation potentials. These results reveal the validity of cystatin C for generating NSCs from ES cells.

Animals↗

PubMed2006

Focal glucose hypermetabolism in interictal state of West syndrome.

This report concerns two siblings from a tetrad, both of whom had West syndrome with atypical findings on positron emission tomography using [(18)F] fluorodeoxyglucose. One manifested periventricular leukoencephalopathy, and the other had periventricular leukoencephalopathy as well as porencephaly because of fetal distress and brain parenchymal hemorrhage in the neonatal period. They developed West syndrome at the age of 9 months. Fluorodeoxyglucose-positron emission tomography study performed after cessation of their seizures revealed an increase in glucose metabolism. The corresponding region presented low-level accumulation in [(11)C]flumazenil positron emission tomography. The patients remained seizure-free for more than 1 month, and their electroencephalograms only occasionally disclosed sporadic paroxysmal discharges. Because of the decreased density of benzodiazepine receptor in these lesions, the activity of the excitatory neuron system may overexpress that of the inhibitory neuron system, thus resulting in epileptogenesis of the lesions. It is suggested that fluorodeoxyglucose and flumazenil-positron emission tomography revealed functional abnormalities and that epileptogenesis of these patients is still active even when the patient is seizure-free and there are mild epileptogenic discharges on electroencephalogram.

Brain↗

PubMed2005

Multi-institutional study on the correlation between chromosomal abnormalities and epilepsy.

While there is an abundance of literature describing the association of chromosome aberrations with epilepsy, only a few refer to the detailed features of epilepsy. It is important to investigate the associations between specific chromosome abnormalities and features of epilepsy to identify genes involved in epilepsy and treat them more effectively. We investigated the correlation between specific chromosome aberrations and epilepsy by sending questionnaires to the members of Kyoto Multi-institutional Study Group of Pediatric Neurology. Seventy-six patients were collected from 10 institutions. Chromosome abnormalities included: Down syndrome (n = 19); Angelman syndrome (n = 8); Prader-Willi syndrome (n = 4); 4p- syndrome (n = 3); 1q- syndrome (n = 2); 5p- syndrome (n = 2); Miller-Dieker syndrome (n = 2); 18q- syndrome; (n = 2); Klinefelter syndrome; (n = 2); and 32 other individual chromosomal aberrations. Overall, the severity of mental retardation correlated with the severity of epilepsy. We could abstract characteristic features of epilepsy in some syndromes. In Angelman and Prader-Willi syndromes, febrile seizures occurred frequently, the onset of epilepsy was in early childhood and seizure phenotype was multiple. Paroxysmal discharge of the occipital region and diffuse high voltage slow wave on electroencephalography were characteristic in Angelman syndrome. In Down syndrome, West syndrome and focal epilepsy were common and the prognosis of epilepsy in West syndrome with Down syndrome was good. In 4p- syndrome, febrile seizures were often seen, and unilateral or generalized clonic or tonic-clonic status epilepticus were characteristic. For the other chromosomal aberrations investigated here, the patient numbers were too small to abstract common features of epilepsy.

Adolescent↗

PubMed2005

[Postoperative complete atrioventricular block induced by carbamazepine in a patient with congenital heart disease].

We report here a boy with epilepsy and congenital heart defect, complicated postoperatively by complete atrioventricular (A-V) block caused by an adverse effect of carbamazepine (CBZ). He had been taking CBZ for 7 years to treat complex partial seizures. He also had endocardial cushion defect and first-degree A-V block, and underwent cardiac surgery at the age of 17 years. The postoperative course was unremarkable except transient complete left bundle branch block occuring one day after the surgery. Oral CBZ (400 mg per day) was continued. Five days after the surgery, bradycardia (20 beats per minute) suddenly developed, and electrocardiography (ECG) showed complete A-V block. Pervenous pacing was begun, and the heart rate gradually recovered. CBZ was discontinued on the suspicion that it caused the arrhythmia, although its serum level was estimated to be within the therapeutic range (4 to 5 microg/ml). He underwent pervenous pacing for 12 days. He was discharged 27 days after the surgery, when ECG returned to first-degree A-V block. In this case, the cardiac conduction system was affected by an adverse effect of CBZ, in combination with the preoperative first-degree A-V block and the effects of cardiac surgery, resulting in complete A-V block. Although reports of similar cases are scarce, caution should be made in prescribing CBZ to patients who either have cardiac conduction abnormalities or undergo cardiac surgery.

Adolescent↗

PubMed2003

[A spontaneous bilateral subdural effusion in an 11-year-old boy with middle cranial fossa arachnoid cyst].

An 11-year-old boy gradually developed headache, vomiting and diplopia over a period of 1 month. Repeated examinations of head CT scan revealed an arachnoid cyst in the right middle cranial fossa and bilateral subdural effusion of enlarging size. Papilledema was absent on admission, but it became evident after 1 week, and lumbar puncture disclosed very high pressure (800 mmH2O) of the cerebrospinal fluid. Fenestration of the cyst to the basal cisterms quickly alleviated his symptoms of intracranial hypertension as well as the bilateral subdural effusion on CT. Macroscopically, there was a small tear on the wall of the arachnoid cyst, and it probably served as a communication valve with the subdural space. Since he had no history of head trauma in the past few months, the reason of the tear formation was unclear. Intracranial arachnoid cyst is a relatively common congenital malformation of usually benign and non-pathogenic nature. However, it may occasionally cause non-traumatic subdural effusion and intracranial hypertension.

Arachnoid Cysts↗

PubMed2003

[Intractable epilepsy (apneic seizure) in an infant with 18q deletion syndrome].

We report here an infant with 18q deletion syndrome, and intractable apneic seizures. He had intrauterine growth retardation and dysmorphic features. Chromosomal analysis demonstrated mosaicism of 18q interstitial deletion (q12.3-q22.3). From the age of 3 months, apneic attacks occurred from once a week to over 10 times a day despite many oral antiepileptic agents, and were diagnosed as complex partial seizures. Ictal electroencephalogram and 18F-fluorodeoxyglucose-positron emission tomography at the age of 10 months identified the epileptic focus in the right parieto-temporal region. He also had severe psychomotor retardation. Head MRI examination revealed diffuse cerebral atrophy and severe white matter dysmyelination, which was caused by the deletion of myelin basic protein gene at the locus of 18q22.3. This locus may be responsible for the clinical manifestations of 18q deletion syndrome. Detailed description of the onset, seizure types, and prognosis of epilepsy associated with 18q deletion syndrome is rare. It was suggested that the locus of 18q21.3-q22.3 was responsible for autonomic seizures in 18q deletion syndrome.

Apnea↗