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Biomedical subjects

Mariko Y Momoi

Publications and source records attributed to Mariko Y Momoi.

At least 19 recordsLinked to original sources
PubMed2006

Intracellular distribution of a speech/language disorder associated FOXP2 mutant.

Although a mutation (R553H) in the forkhead box (FOX)P2 gene is associated with speech/language disorder, little is known about the function of FOXP2 or its relevance to this disorder. In the present study, we identify the forkhead nuclear localization domains that contribute to the cellular distribution of FOXP2. Nuclear localization of FOXP2 depended on two distally separated nuclear localization signals in the forkhead domain. A truncated version of FOXP2 lacking the leu-zip, Zn2+ finger, and forkhead domains that was observed in another patient with speech abnormalities demonstrated an aggregated cytoplasmic localization. Furthermore, FOXP2 (R553H) mainly exhibited a cytoplasmic localization despite retaining interactions with nuclear transport proteins (importin alpha and beta). Interestingly, wild type FOXP2 promoted the transport of FOXP2 (R553H) into the nucleus. Mutant and wild type FOXP2 heterodimers in the nucleus or FOXP2 R553H in the cytoplasm may underlie the pathogenesis of the autosomal dominant speech/language disorder.

Amino Acid Sequence↗
PubMed2006

Secretin receptor-deficient mice exhibit impaired synaptic plasticity and social behavior.

Secretin is a peptide hormone released from the duodenum to stimulate the secretion of digestive juice by the pancreas. Secretin also functions as a neuropeptide hormone in the brain, and exogenous administration has been reported to alleviate symptoms in some patients with autism. We have generated secretin receptor-deficient mice to explore the relationship between secretin signaling in the brain and behavioral phenotypes. Secretin receptor-deficient mice are overtly normal and fertile; however, synaptic plasticity in the hippocampus is impaired and there are slightly fewer dendritic spines in the CA1 hippocampal pyramidal cells. Furthermore, secretin receptor-deficient mice show abnormal social and cognitive behaviors. These findings suggest that the secretin receptor system has an important role in the central nervous system relating to social behavior.

Animals↗
PubMed2006

Elevated CSF IL-6 in a patient with respiratory syncytial virus encephalopathy.

The patient was an 11-month-old boy who developed encephalopathy associated with respiratory syncytial virus bronchiolitis. Right hemispheric encephalopathy was indicated by left hemiparesis and a diffuse right hemispheric lesion detected with magnetic resonance imaging. Elevated levels of interleukin-6 in the cerebrospinal fluid during the acute phase suggested the involvement of increased production of one or more cytokines in the pathogenesis of viral related encephalopathy, similarly to that proposed for influenza encephalopathy.

Brain Diseases↗
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↗
PubMed2005

Blood chimerism in monochorionic twins conceived by induced ovulation: case report.

A case of monochorionic twin boys delivered at 34 weeks of gestation following induced ovulation with clomiphene is described. One twin was typed as blood group AB and the other as B. Flow cytometry showed blood group chimerism. DNA polymorphism analysis of peripheral lymphocytes and hair root cells showed that the chimerism was confined to the blood cells and they were dizygotic.

ABO Blood-Group System↗
PubMed2005

RSK2 gene mutations in Coffin-Lowry syndrome with drop episodes.

Coffin-Lowry syndrome is an X-linked mental retardation disorder with dysmorphism caused by mutation of the ribosomal S6 kinase (RSK2) gene. Coffin-Lowry syndrome patients can experience unusual drop episodes whereby an abrupt loss of muscle tone and falling down can be induced by sudden, unexpected tactile or auditory stimuli. We detected a C913T (R305X) mutation in a female Coffin-Lowry syndrome patient with drop episodes. All mutations in our patient and those previously reported in patients with drop episodes result in premature truncation of the RSK2 protein in the N-terminal kinase domain or upstream of this domain.

Adult↗
PubMed2005

Absence of causative mutations and presence of autism-related allele in FOXP2 in Japanese autistic patients.

We analyzed the FOXP2 gene, which encodes a putative transcription factor containing a polyglutamine tract and a forkhead DNA-binding domain, for a possible causative mutation in autism. FOXP2 was reported to be mutated in patients with a severe speech and language disorder. FOXP2 was located on chromosome 7q31, which is one of the loci involved in autism. Autism and specific language impairment share some of their clinical phenotypes. In addition, FOXP2 was expressed abundantly in the brain. We screened all of the exons of FOXP2 for causative mutations in 53 Japanese autistic patients using denaturing high-performance liquid chromatography and direct sequencing. A delCAA in exon 5 causing one glutamine deletion in the first polyglutamine tract was detected in four patients and in 2 of 50 control individuals. The frequency of the TT allele with the G to T base change in intron 15 was significantly high in the autistic population. The other base changes included one silent base change (A569G) in exon 5 and three in introns. Our results may suggest a relationship between autism and the FOXP2 gene or a gene located nearby.

Adolescent↗
PubMed2005

Mutation analysis of methyl-CpG binding protein family genes in autistic patients.

Methyl-CpG binding protein 2 gene (MECP2), the gene implicated in Rett syndrome, was also reported to be involved in mental retardation and autism. MECP2, MBD1, MBD2, MBD3, and MBD4 comprise a nuclear protein family sharing the methyl-CpG binding domain (MBD) and are related to transcriptional repression. In 65 Japanese autistic patients, all the exons of each gene were screened for mutations by DHPLC, and the results were confirmed by direct sequencing. An R269C mutation that resulted in the addition of cysteine near a cysteine rich region was found in the MBD1 gene in one patient. This mutation was also detected in the patient's father with some phenotypes of autism and his normal sister, but not in 151 controls. Two repeat length polymorphisms, (GGGGCC)2 to 3 and (GGC)4 to 5, were detected in MBD2, and several polymorphisms were detected in each gene. Although our findings could not confirm that the genes of this family are responsible for the etiology in the majority of autistic patients, the R269C mutation in the MBD1 gene may relate to autism. The potential association of the high-polymorphic gene variants with autism needs to be studied further. Furthermore, these polymorphisms are useful for linkage analysis.

Amino Acid Sequence↗
PubMed2005

Early-onset ataxia with oculomotor apraxia with a novel APTX mutation.

Early-onset ataxia with oculomotor apraxia and hypoalbuminemia is an autosomal recessive cerebellar ataxia characterized by oculomotor apraxia, peripheral neuropathy, and hypoalbuminemia. Mutations in aprataxin gene located at chromosome 9q13 have been identified recently in Japanese and European patients. This study reports two cases of siblings with early-onset ataxia with oculomotor apraxia and hypoalbuminemia, which manifested early onset before 2 years of age with relatively rapid progression and severe dystonia. Both of the siblings were compound heterozygotes with aprataxin gene mutations, 689 insT and G692A, in exon 5 that encodes the histidine triad domain of the aprataxin protein. The novel missense mutation, G692A, was not present in 40 unrelated and unaffected individuals.

Adolescent↗
PubMed2005

Obstructive jaundice as a presentation of ganglioneuroblastoma.

Obstructive jaundice is a rare symptom in the neuroblastic tumor. Seven cases of obstructive jaundice caused by neuroblastoma have been reported, and only three of these patients had the symptom at the onset of the disease. The authors report a case of ganglioneuroblastoma presenting with obstructive jaundice as a rare initial feature. After the histologic diagnosis with open biopsy, chemotherapy consisting of cisplatin, pirarubicin hydrochloride/doxorubicin, cyclophosphamide, and vincristine was given. The treatment resulted in reduction in the tumor size and relief of the obstructive jaundice. Complete resection of the tumor was possible after five courses of chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Two new XPD patients compound heterozygous for the same mutation demonstrate diverse clinical features.

Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are both rare autosomal recessive disorders with defects in DNA repair. They are usually distinct both clinically and genetically but in rare cases, patients exhibit the clinical characteristics of both diseases concurrently. We report two new phenotypically distinct cases of XP with additional features of CS (xeroderma pigmentosum and Cockayne syndrome crossover syndrome (XP/CS)) carrying an identical mutation (G47R) in the XPD gene within the N terminus of the protein. Both patients had clinical features of XP and CS but only one fulfilled most criteria for diagnosing CS. Unusually, patient 1 developed early skin cancer, in contrast to patient 2, who never developed any malignancies. Cells from both these patients have repair defects typical of xeroderma pigmentosum complementation group D (XPD) cells, but also had the phenotype of uncontrolled DNA breakage found specifically in XPD/CS cells and similarly reduced levels of TFIIH. Despite these similarities between our two patients, their clinical features are quite different and the clinical severity correlates with other cellular responses to ultraviolet irradiation.

Adult↗
PubMed2005

[Pediatric neurology practice after adolescence].

To evaluate the current situations in child neurology practice for the patients after adolescence, a questionnaire was sent to 205 child neurologists. Major issues encountered in such practice included inpatient facilities, community medical networks, a training system for adult medicine, and financial support for such patients. Not only a system for practice, but also a continuing information transfer system between child specialists and adult specialists is needed.

Adolescent↗
PubMed2004

Non-invasive screening of fragile X syndrome A using urine and hair roots.

The diagnosis of fragile X A syndrome (FRAXA) during childhood depends largely on DNA-based diagnostic tests due to the lack of the specific clinical features. To determine a non-invasive screening method for fragile X syndrome, we studied the method of DNA-based diagnosis using urine or hair roots instead of routinely used peripheral blood cells. The amplification of repeat-containing alleles of FMR-1 by PCR using Pfu polymerase was applied on DNA extracted from urine sediments or hair roots of 50 and 28 normal individuals, respectively. Consistent amplification of repeat-containing DNA fragments of normal size to ethidium-visible quantities were obtained in 92% (46/50) of urine samples and 100% (28/28) of hair roots. No bands of normal size or abnormal or artificial smears were detected in two male FRAXA patients. No female samples were examined in the present study because the separation of two alleles was unsatisfactory on agarose gels with DNA from blood samples. Our results indicate that the use of hair roots in a DNA-based test constitutes a rapid, simple and less-invasive screen to diagnose males with FRAXA.

Adolescent↗
PubMed2004

Dichloroacetate treatment for mitochondrial cytopathy: long-term effects in MELAS.

The long-term effects of the sodium salt of dichloroacetic acid (DCA) were evaluated in four patients with mitochondrial encephalomyelopathy with lactic acidosis and stroke-like episodes (MELAS) carrying A3243G mutation. Oral administration of DCA in MELAS patients was followed for an average of 5 years 4 months. Serum levels of lactate and pyruvate were maintained at around 10 and 0.6 mg/dl, respectively. Serum levels of DCA were 40-136 microg/ml. Symptoms responding to treatment included persistent headache, abdominal pain, muscle weakness, and stroke-like episodes. In contrast, no improvements in mental status, deafness, short stature, or neuroelectrophysiological findings were observed. Adverse effects included mild liver dysfunction in all patients, hypocalcemia in three and peripheral neuropathy in one. None of these adverse events was severe enough to require discontinuation of treatment. To determine suitable indications for DCA therapy, analysis of many more patients who have undergone DCA administration is required.

Abdominal Pain↗
PubMed2004

[Magnetic resonance findings in a case of Gradenigo syndrome: widespread inflammation involving the paranasal sinuses and middle ear].

Gradenigo syndrome is a rare condition consisting of otitis media, trigeminal neuralgia and abducens palsy. We report here a 6-year-old girl with this syndrome. Cranial magnetic resonance imaging (MRI) demonstrated inflammatory lesions in the left petrous apex and cavernous sinus, as well as stenosis of the left carotid artery. She was conservatively treated with antibiotics, which successfully improved her clinical and MRI findings. Surgical treatment including mastoidectomy was avoided. This case illustrates the usefulness of MRI in the diagnosis and management of Gradenigo syndrome.

Abducens Nerve Diseases↗
PubMed2003

Absence of allelic loss in cytomegalic neurons of cortical tuber in the Eker rat model of tuberous sclerosis.

The Eker rat is an animal model of tuberous sclerosis caused by a mutation in the Tsc2 gene encoding a tumor suppressor protein, tuberin. According to Knudson's two-hit theory, renal carcinomas and other tumors develop in various organs. Although the incidence of brain lesions is lower in the Eker rat than in human tuberous sclerosis, a cortical tuber was recently found in the cerebrum of an Eker carrier. In this study, we examined whether neuronal cytomegaly in the Eker rat tuber is caused by deletion of the normal Tsc2 allele and resultant loss of tuberin, as is the case with the majority of renal carcinomas. A combination of laser capture microdissection and semi-nested polymerase chain reaction demonstrated the presence of the wild-type Tsc2 allele in the cytomegalic neurons isolated individually. Immunohistochemistry also detected positive tuberin immunoreactivity in many of these giant neurons. These findings were in sharp contrast to those of renal carcinoma cells deriving from allelic loss. Our results provide evidence that many if not all cytomegalic neurons of a cortical tuber occur in the absence of allelic loss.

Animals↗
PubMed2003

Autonomic function in Kawasaki disease with myocardial infarction: usefulness of monitoring heart rate variability.

BACKGROUND: Despite anticoagulant therapy, many patients with Kawasaki disease and giant coronary artery aneurysm develop myocardial infarction. These patients have a high risk of sudden death, but the etiology is not clear. We studied autonomic function and the possibility of malignant ventricular arrhythmia through heart rate variability. METHODS: We studied six Kawasaki disease patients with myocardial infarction and 16 normal controls. Heart rate variability was investigated using a 24 h electrocardiogram. We assessed the standard deviation from the mean of the normal R-R intervals (SDNN), the proportion of adjacent R-R intervals with a difference greater than 50 msec (pNN50) and the root-mean square of successive R-R differences as time-domain analysis (rMSSD). We assessed very low-frequency power, low-frequency power (LF), high-frequency power (HF) and the LF/HF ratio in frequency-domain analysis. RESULTS: There was no significant difference in SDNN, but there was a significant difference in pNN50 and rMSSD. Patients with Kawasaki disease showed lower HF and higher LF/HF than normal controls. CONCLUSION: Our findings suggest that patients with Kawasaki disease and myocardial infarction show decreased vagal activity, which could cause malignant arrhythmia.

Adolescent↗