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Biomedical subjects

Hideo Yamanouchi

Publications and source records attributed to Hideo Yamanouchi.

At least 19 recordsLinked to original sources
PubMed2007

Genotype-phenotype correlations of KCNJ2 mutations in Japanese patients with Andersen-Tawil syndrome.

Andersen-Tawil syndrome (ATS) is a rare inherited disorder characterized by periodic paralysis, mild dysmorphic features, and QT or QU prolongation with ventricular arrhythmias in electrocardiograms (ECGs). Mutations of KCNJ2, encoding the human inward rectifying potassium channel Kir 2.1, have been identified in patients with ATS. We aimed to clarify the genotype-phenotype correlations in ATS patients. We screened 23 clinically diagnosed ATS patients from 13 unrelated Japanese families. Ten different forms of KCNJ2 mutations were identified in the 23 ATS patients included in this study. Their ECGs showed normal QTc intervals and abnormal U waves with QUc prolongation and a variety of ventricular arrhythmias. Especially, bidirectional ventricular tachycardia (VT) was observed in 13 of 23 patients (57%). Periodic paralysis was seen in 13 of 23 carriers (57%), dysmorphic features in 17 (74%), and seizures during infancy in 4 (17%). Functional assays for the two novel KCNJ2 mutations (c. 200G>A (p. R67Q) and c. 436G>A (p. G146S)) displayed no functional inward rectifying currents in a heterologous expression system and showed strong dominant negative effects when co-expressed with wild-type KCNJ2 channels (91% and 84% reduction at -50 mV respectively compared to wild-type alone). Immunocytochemistry and confocal imaging revealed normal trafficking for mutant channels. In our study, all of the clinically diagnosed ATS patients had KCNJ2 mutations and showed a high penetrance with regard to the typical cardiac phenotypes: predominant U wave and ventricular arrhythmias, typically bidirectional VT.

Adolescent↗
PubMed2006

Acute infantile encephalopathy predominantly affecting the frontal lobes (AIEF): a novel clinical category and its tentative diagnostic criteria.

Acute infantile encephalopathy predominantly affecting the frontal lobes (AIEF) is proposed as a novel form of acute encephalopathy in infancy. To establish the diagnostic criteria for AIEF, we reviewed the clinical data of 10 patients who were seen by us and diagnosed as having AIEF, and those of 7 patients in the literature compatible with the diagnosis of AIEF. The mean age of onset was 1 year and 7 months. Boys and girls were equally affected. There is always an association with hyperpyrexia due to viral illness. Manifestations at the onset were convulsive status epilepticus and prolonged coma followed by signs of frontal lobe dysfunction such as a lack of spontaneity and regression of verbal functions. Imaging studies demonstrated edematous changes of the bilateral frontal lobes, which showed increased cerebral perfusion initially but attenuated perfusion several weeks later. The recovery of intellectual deficit was generally slower than that of motor disability. Based on these findings, we propose tentative diagnostic criteria of AIEF.

Acute Disease↗
PubMed2006

Acute infantile encephalopathy predominantly affecting the frontal lobes.

To establish a novel subtype of acute infantile encephalopathy, the clinical and radiologic features of nine infants with acute encephalopathy involving the bilateral frontal lobes were examined. These patients had convulsive status epilepticus with hyperpyrexia followed by a prolonged impairment of consciousness for 2-20 days. After the recovery of consciousness, all the patients manifested regression of verbal function and lack of spontaneity. Some of them also exhibited stereotypic movements, instability of mood, or catalepsy. Transient postictal edema in both frontal lobes was suggested by diffusion-weighted magnetic resonance imaging. Attenuated cerebral perfusion in the frontal lobes was demonstrated by single-photon emission computed tomography at the tenth day after onset or subsequently. Serial studies disclosed atrophic changes in the frontal lobes. All patients manifested regression or retardation of motor and verbal functions. The recovery of intellectual deficit was slower and less prominent than that of motor dysfunction. These unique features suggest that the frontal lobes are the focus of this novel subtype of acute encephalopathy, which we propose to call acute infantile encephalopathy predominantly affecting the frontal lobes.

Brain Diseases↗
PubMed2006

Callosal agenesis followed postnatally after prenatal diagnosis.

Callosal agenesis is a congenital brain anomaly caused by embryonal hypogenesis of the corpus callosum. Concerning the neurological prognosis, epilepsy and motor disturbance are noted in some cases, while many cases are asymptomatic and the prognosis is good. We report a fetus tentatively diagnosed with hydrocephaly on prenatal echo-encephalography, which was performed without adequate explanation to and understanding of the parents. The parents had not expected an abnormality before the screening, and were subsequently not psychologically prepared for the discovery of the congenital brain anomaly on imaging. Moreover, they received no guidance on how to deal with any possible abnormalities. The pregnant mother was referred to our hospital. Prenatal MRI was performed after informed consent was obtained, and the fetus was diagnosed with callosal agenesis. The patient was followed for 5 years, and neurological development was normal. However, the parents have remained anxious while raising the child. Thus, the prenatal diagnosis of callosal agenesis in this case caused unnecessary mental burden to the parents. Here, we report the course of the case, and discuss the way prenatal ultrasonography should be used as a prenatal screening method, and the importance of counseling before the test.

Agenesis of Corpus Callosum↗
PubMed2006

Expression of the N-methyl-D-aspartate receptor subunit R1 in the developing human hippocampus.

It has been suggested that the N-methyl-D-aspartate (NMDA) receptor family plays a key role in synaptic plasticity and synaptogenesis that is essential for memory, learning, differentiation, and development. Although gene expression of these receptors has been analyzed in the experimental animal brain and in some diseases of the adult or elderly human brain, it has not been studied in the developing human brain. Using in situ hybridization, we investigated the expression of the NMDAR1 gene in the hippocampi of 16 human neonates who were between 22 and 40 weeks of gestation and had no evidence of critical episodes of brain insult at autopsy. Signals for NMDAR1 were detected ubiquitously at all developmental stages. Dense hybridization signals were uniformly detected in the granular cells of the dentate gyrus in all specimens. Stronger signals were observed in the larger-type pyramidal cells in the CA2 and CA3 regions compared with the pattern seen in the CA1 region in the smaller-type pyramidal cells. These results suggest that the NMDAR1 gene is expressed at 22 weeks and possibly occurs earlier in neuronal cell bodies of the dentate gyrus and all CA fields of Ammon's horn and that the NMDAR plays an important role in constructing neuronal networks in developing human brains.

Age Factors↗
PubMed2006

[Etiology and management of neonatal seizures--successful treatment by midazolam].

Etiology and management of neonatal seizures was retrospectively studied in 39 patients, who were admitted in our neonatal intensive care unit. Midazolam was administered to 22 patients by intravenous bolus injection (0.15 +/- 0.08 mg/kg) and/or continuous intravenous infusion (0.33 mg +/- 0.11 mg/kg/hr), both of which were judged as effective in 71% and 76% of the patients, respectively. Seven patients showed decrease of blood pressure possibly related with administration of midazolam, but five of them were managed by decreasing dose of the drug or observation of clinical pictures. We consider that midazolam is effective and relatively safe for the management of neonatal seizures.

Humans↗
PubMed2006

[Neurological complications during and after the treatment of acute lymphocytic leukemia].

To explore the frequency and prognosis of neurological complications of acute lymphocytic leukemia, retrospective studies were made of patients with acute lymphocytic leukemia. Neurological complications were found in 13 of 100 patients during and after treatment. They were caused by chemotherapy in 8 patients, irradiation therapy in 2, vitamin B1 deficiency in 1, and unknown in 2. Medications primarily relevant to these complications were methotrexate in 5 patients, L-asparaginase in 2, cytosin arabinoside in 1. The patients were diagnosed as having leukoencephalopathy (8), cerebrovascular injury (4), and Wernicke's encephalopathy (1). Symptomatic epilepsy was found in one patient, and mental retardation was seen in three patients during a 2-year course of treatment. We conclude that careful management is required in the treatment of acute lymphocytic leukemia, because of the persistence of neurological complications, although their severity is decreasing with advances in treatment.

Adolescent↗
PubMed2005

An analysis of epilepsy with chromosomal abnormalities.

We retrospectively reviewed the medical records of neonates with chromosomal abnormalities and epilepsy who had been admitted to the neonatal intensive care unit (NICU) and followed up at the outpatient clinic of Dokkyo University School of Medicine. Chromosomal anomalies were diagnosed in 128 of 5789 patients admitted from 1978 through 2001. Seventy-one neonates had trisomy 21, 29 had trisomy 18, 8 had trisomy 13, and 20 had other chromosomal anomalies. Seizures occurred in five patients with trisomy 21 and in one patient each with trisomy 18, 6q-, 13q-, 21q-, and mosaicism trisomy 13. Two patients with 4p- [Wolf-Hirschhorn syndrome] were admitted to the NICU, but were not followed up at our outpatient clinic. The boy with 6q- (46,XY,-6, +der(6)t(6;11)(q25.1;q23.3)mat) had agenesis of the corpus callosum and multiple congenital anomalies as well as intractable epilepsy. The girl with 13q- (46, XX, t(2,4)(q24.2;p14), del (13)(q21.2q31.2)) had infantile spasms at 12 months, which were well controlled with nitrazepam and vitamin B6. The girl with mosaic trisomy 8q; (46, XX, der(8) (qter-->q11.2::p23.3-->qter)/46, XX), was not born at our hospital, but showed unique clinical features. She had intractable epilepsy characterized by episodes of vomiting and staring with astatic seizures. Computed tomography of the brain revealed bilateral calcification in the globus pallidus, associated with bursts of high-amplitude slow waves on electroencephalography. One of the two patients with del(15)(q12)[Angelman syndrome] had giant-amplitude visual evoked potential, suggesting hyperexcitability of the visual cortex.

Brain↗
PubMed2005

Is the questionnaire for the assessment of gastroesophageal reflux useful for diabetic patients?

OBJECTIVE: It has been suggested that the questionnaire reported by Carlsson et al. has high sensitivity in diagnosing gastroesophageal reflux disease (GERD) and is considered to be one of the most useful diagnostic tools for GERD. The aim of the present study was to evaluate the ability of the questionnaire to identify gastroesophageal reflux (GER) diagnosed by 24-h pH monitoring in diabetic patients. MATERIAL AND METHODS: Fifty-three patients with type 2 diabetes were enrolled in the present study. GER was monitored by means of an antimony electrode. Patients completed the questionnaires immediately before undergoing pH monitoring. RESULTS: Diabetic patients were found to have few symptoms, and the average score on the questionnaire was extremely low. No significant difference in scores on the questionnaire was observed between patients with and those without GER. CONCLUSIONS: The questionnaire was shown not to be useful for diagnosing GER as a complication in diabetic patients. We, therefore, should not diagnose GER as a complication in diabetes mellitus on the basis of the questionnaire.

Adult↗
PubMed2005

Activated remodeling and N-methyl-D-aspartate (NMDA) receptors in cortical dysplasia.

Cortical dysplasia is now recognized as one of the major etiologies causing intractable epilepsy in childhood. Dysplastic cortex displays cortical dyslamination, which is often associated with dysmorphic large neurons and less frequently with balloon cells. The dysmorphic large neurons are commonly located in the subcortical white matter and cerebral cortex, with enlarged nuclei with a single prominent nucleolus and showing aberrant cytoskeletal changes. I have shown that dysmorphic large neurons have several immature types of cytoskeletal proteins, such as the low-molecular-weight form of microtubule-associated protein 2 (MAP2) and MAP1B, which are involved in the outgrowth and modeling of neuronal processes in the immature brain. I have also reported that dysmorphic large neurons also have enhanced gene expression of growth-associated protein GAP43, which is a phosphoprotein enriched at presynaptic nerve terminals and is thought to be involved in axonal outgrowth and plasticity in synaptic connections. Finally, I have shown that the N-methyl-D-aspartate acid (NMDA) receptor R1 gene is up-regulated in the dysmorphic large neurons and nearly normal-sized neurons located in the dysplastic cortex. This evidence suggests that growth of neuronal processes and activated excitatory synaptic remodeling exist in the epileptic conditions of cortical dysplasia.

Cerebral Cortex↗
PubMed2004

Spontaneous improvement of intractable epileptic seizures following acute viral infections.

In general, epileptic seizures become more serious following infections. However, transient and permanent improvement of epileptic seizures has been observed following acute viral infections, without a recent change in anti-epileptic therapy. Questionnaires were sent to 73 institutions, throughout Japan, where pediatric neurologists care for children with epilepsy to characterize this phenomenon through clinician survey. Completed surveys were received from 11 institutions, and 21 cases were selected for the study. The age of the patients were 6 months to 17 years. The West syndrome or epilepsy subsequent to West syndrome cases were 16 out of 21. Two cases of symptomatic generalized epilepsy and one case each of symptomatic partial epilepsy, continuous spike-waves of slow sleep and severe myoclonic epilepsy in infancy were also reported. These seizures disappeared within 2 weeks subsequent to viral infections such as, exanthema subitum, rotavirus colitis, measles and mumps. The disappearance of intractable epileptic seizures following acute viral infections might be related to the inflammatory processes or the increased levels of antibodies after viral infections.

Acute Disease↗
PubMed2003

Worldwide distribution and broader clinical spectrum of muscle-eye-brain disease.

Muscle-eye-brain disease (MEB), an autosomal recessive disorder prevalent in Finland, is characterized by congenital muscular dystrophy, brain malformation and ocular abnormalities. Since the MEB phenotype overlaps substantially with those of Fukuyama-type congenital muscular dystrophy (FCMD) and Walker-Warburg syndrome (WWS), these three diseases are thought to result from a similar pathomechanism. Recently, we showed that MEB is caused by mutations in the protein O-linked mannose beta1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) gene. We describe here the identification of seven novel disease-causing mutations in six of not only non-Finnish Caucasian but also Japanese and Korean patients with suspected MEB, severe FCMD or WWS. Including six previously reported mutations, the 13 disease-causing mutations we have found thus far are dispersed throughout the entire POMGnT1 gene. We also observed a slight correlation between the location of the mutation and clinical severity in the brain: patients with mutations near the 5' terminus of the POMGnT1 coding region show relatively severe brain symptoms such as hydrocephalus, while patients with mutations near the 3' terminus have milder phenotypes. Our results indicate that MEB may exist in population groups outside of Finland, with a worldwide distribution beyond our expectations, and that the clinical spectrum of MEB is broader than recognized previously. These findings emphasize the importance of considering MEB and searching for POMGnT1 mutations in WWS or other congenital muscular dystrophy patients worldwide.

Adult↗
PubMed2003

Reversible altered consciousness with brain atrophy caused by valproic acid.

A 5-year-old female developed alteration of consciousness during 3 days of long-term treatment with valproic acid for localization-related epilepsy. Computed tomography revealed cerebral atrophy, and electroencephalography presented slow background activity. Consciousness cleared only 12 hours after valproic acid was discontinued, and normal electroencephalography results were evident 1 week later. Cerebral atrophy was nonexistent 2 months later. This rapidly developing but reversible alteration of consciousness in parallel with brain atrophy is recognized as a rare idiosyncratic adverse effect of valproic acid.

Atrophy↗
PubMed2002

Doublecortin immunoreactivity in giant cells of tuberous sclerosis and focal cortical dysplasia.

Cerebral cortical lesions of tuberous sclerosis (TSC) and focal cortical dysplasia (FCD) show disturbances in laminar architecture and cellular differentiation. We immunohistochemically studied the expression of doublecortin, a fetal neuronal protein that regulates neuronal migration, in the surgical specimens of five TSC and eight FCD patients. In both TSC and FCD, bizarre giant cells showed a variable degree of doublecortin immunoreactivity. Both cytomegalic neurons and balloon cells were positive. The staining tended to be more intense in TSC than in FCD, although there were exceptional cases in both groups. Doublecortin immunoreactivity of normal-sized neural cells was restricted to a small number of astrocytes, and comparable to that in control patients. The persistent expression of doublecortin by giant cells in the postnatal cerebrum is additional evidence of abnormal differentiation, which may be relevant to the pathogenesis of cortical disarray in TSC and FCD.

Cerebral Cortex↗
PubMed2002

An autopsy case of ornithine transcarbamylase deficiency.

We present an autopsy case of ornithine transcarbamylase (OTC) deficiency with grumose degeneration in the dentate nucleus of the cerebellum. The patient had intractable neonatal convulsions and hyperammonemia from the 3rd day after birth. Diagnosis of OTC deficiency was made based on null activity of the enzyme and four-base deletions in exon 9 of the OTC gene. Death was due to sepsis as well as disseminated intravascular coagulation at 1 year and 2 months of age. Neuropathology showed multiple cystic changes and ulegyria in the bilateral frontal and parietal lobes. Multiple cysts were associated with the region, which was infiltrated with macrophages surrounded by astroglia showing palisading pattern. Ferrugination was marked in the thalamus and severe neuronal loss with astrogliotic change in the CA1-2 area of the hippocampus. Grumose degeneration was noted in the dentate nucleus of the cerebellum. This is the first report of grumose degeneration in OTC deficiency.

Autopsy↗
PubMed2002

Congenital bilateral perisylvian syndrome associated with congenital constriction band syndrome.

We report a 7-year-old boy with congenital bilateral perisylvian syndrome and congenital constriction band syndrome. The former is a congenital neurologic syndrome characterized by pseudobulbar palsy, mental retardation, epilepsy, and bilateral perisylvian polymicrogyria The latter is a malformative disorder with digital ring constrictions and amputations, probably caused by early amnion rupture resulting in entanglement of fetal parts by amniotic strands. We believe that the combination of these two malfornative disorders was not coincidental; instead, fetal circulatory disturbance related to chronic abruptio placentae could account for this combination.

Amniotic Band Syndrome↗
PubMed2002

The distribution and number of Leu-7 (CD57) positive cells in lung tissue from patients with pulmonary fibrosis.

Leu-7 positive lymphocytes, including natural killer cells, play an important role in the immune system's surveillance function to prevent the development of cancer. The incidence of lung cancer is significantly high in patients with end-stage pulmonary fibrosis. We hypothesized that the number of Leu-7 positive cells may be decreased in areas of severe pulmonary fibrosis. To demonstrate this, Leu-7 positive cells were immunohistochemically stained in 41 lung specimens obtained from patients with idiopathic pulmonary fibrosis and pulmonary fibrosis associated with collagen vascular disorders. The number of Leu-7 positive cells was evaluated according to the pathological findings. In pathologically normal lung, Leu-7 positive cells were mostly found within the capillaries of the septa and rarely in the alveolar space or the stroma. The number of Leu-7 positive cells was 0.69 +/- 0.15 in areas of advanced fibrosis (n = 41), 2.39 +/- 0.60 in areas that had newly developeing fibrosis (n = 41), 1.14 +/- 0.57 in bronchiolitis obliterans organizing pneumonia (n = 9), and 1.35 +/- 0.87 in diffuse alveolar damage (DAD) (n = 11). The number of Leu-7 positive cells in areas of newly developing fibrosis (2.39 +/- 0.60) was significantly higher than that in areas of established fibrosis (0.69 +/- 0.15, P < 0.05). Our present study demonstrates a significant decrease in the number of Leu-7 positive cells in areas of advanced fibrosis. This evidence may partly explain the high incidence of lung cancer associated with pulmonary fibrosis.

Aged↗