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Ken Inoue

Publications and source records attributed to Ken Inoue.

At least 37 records · Page 2Linked to original sources
PubMed2005

Prenatal diagnosis of PLP1 copy number by array comparative genomic hybridization.

OBJECTIVES: To report a family with a history of Pelizaeus-Merzbacher disease (PMD) for which prenatal diagnosis of PLP1 gene duplication status was attempted by the use of custom array comparative genomic hybridization (aCGH). METHODS: A 28-year-old woman was referred for genetic counseling for her then current pregnancy because her existing 3-year-old son was diagnosed with a classic form of PMD. At 11 and 3/7 weeks gestation, chorionic villus sampling (CVS) was performed. Custom aCGH and fluorescence in situ hybridization (FISH) analyses were also performed on the DNA from family members. Fetal karyotyping revealed 46,XY. RESULTS: Analysis by aCGH revealed that the male fetus was not duplicated for the PLP1 gene, but confirmed a duplicated PLP1 gene in the 3-year-old son, and that the mother was a duplication carrier. These results were independently confirmed by FISH analysis. aCGH and FISH analyses on DNA and cells derived from cord blood confirmed PLP1 nonduplication in the newborn. CONCLUSION: aCGH is a reliable alternative method for detection of PLP1 copy number for prenatal diagnosis of Pelizaeus-Merzbacher disease.

Adult↗
PubMed2005

Underlying factors for the rapid increase of suicide in Mie Prefecture, Japan.

The number of suicides in Japan increased from about 22,000 per year during the period 1988 to 1997 to over 30,000 since 1998. The number of suicides has also been increasing in Mie Prefecture. In the present study we examined the incidence and the circumstances for all suicidal cases during the seven-year period, 1996-2002, that were reported to Mie Prefectural Police Headquarters. In Mie Prefecture, the number of suicides per year averaged 421 cases: from a minimum of 319 in 1997 to a maximum of 501 in 1998. The most frequent month for suicides was July, while the lowest number occurred in February. Suicide was most common in the 50-59 year age group in men, and in the 70-79 year group in women. Regarding the means of suicide, hanging was the most frequent (61.6%) in both sexes. Psychiatric disorders were the most serious causative factors in all generations, accounting for 23.8% in general but being especially prevalent in the younger generation of people under 39 years. Further reasons for suicide were economic problems for the 40-64 age-group in men and suffering from illness for the elderly age-groups in both sexes. In order to prevent suicide, urgent strategies for effective medical treatments and improved working circumstances are required.

Adult↗
PubMed2004

PLP1-related inherited dysmyelinating disorders: Pelizaeus-Merzbacher disease and spastic paraplegia type 2.

Pelizaeus-Merzbacher disease (PMD) and its allelic disorder, spastic paraplegia type 2 (SPG2), are among the best-characterized dysmyelinating leukodystrophies of the central nervous system (CNS). Both PMD and SPG2 are caused by mutations in the proteolipid protein 1 (PLP1) gene, which encodes a major component of CNS myelin proteins. Distinct types of mutations, including point mutations and genomic duplications and deletions, have been identified as causes of PMD/SPG2 that act through different molecular mechanisms. Studies of various PLP1 mutants in humans and animal models have shed light on the genomic, molecular, and cellular pathogeneses of PMD/SPG2. Recent discoveries include complex mutational mechanisms and associated disease phenotypes, novel cellular pathways that lead to the degeneration of oligodendrocytes, and genomic architectural features that result in unique chromosomal rearrangements. Here, I review the previous and current knowledge of the molecular pathogenesis of PMD/SPG2 and delineate future directions for PMD/SPG2 studies.

Gene Duplication↗
PubMed2004

NMDA receptor-dependent long-term potentiation is dependent on low-voltage-activated calcium currents in the sensorimotor cortex of cats.

The role of low-voltage-activated (LVA) calcium channels in the expression of long-term potentiation (LTP) was examined by intracellular recording in slices from cat agranular cortex. In the normal solution, LTP was induced, and the potentiation of low-threshold rebound potential was evoked by negative current injection. In the cells, in which resting membrane potential was depolarized, the incidence of LTP was very low. LTP was blocked completely in the presence of NMDA receptor antagonist or 50-100 microM nickel. It was suggested that LVA calcium channels function downstream of NMDA receptor-dependent signaling.

2-Amino-5-phosphonovalerate↗
PubMed2004

Human reactions to physical stimulus and the removal of such stimulus as recorded by magnetoencephalography.

We studied the cortical evoked fields elicited by the examiner's touch on glabrous skin of the subject's index finger. Two main components of evoked fields were elicited, and these dipoles were located in the primary somatosensory cortex contralateral to the side of the subject's index finger touched by the examiner. When the timing of removal of the examiner's finger triggered the data acquisition using the photosensor, the strength of the dipole from early evoked fields was stronger than that from late ones. We showed that these evoked fields were elicited by removal and touch of the examiner's finger respectively in response to the mechanical compression and decompression of the skin.

Adult↗
PubMed2004

Molecular mechanism for distinct neurological phenotypes conveyed by allelic truncating mutations.

The molecular mechanisms by which different mutations in the same gene can result in distinct disease phenotypes remain largely unknown. Truncating mutations of SOX10 cause either a complex neurocristopathy designated PCWH or a more restricted phenotype known as Waardenburg-Shah syndrome (WS4; OMIM 277580). Here we report that although all nonsense and frameshift mutations that cause premature termination of translation generate truncated SOX10 proteins with potent dominant-negative activity, the more severe disease phenotype, PCWH, is realized only when the mutant mRNAs escape the nonsense-mediated decay (NMD) pathway. We observe similar results for truncating mutations of MPZ that convey distinct myelinopathies. Our experiments show that triggering NMD and escaping NMD may cause distinct neurological phenotypes.

Alleles↗
PubMed2004

Disinhibition of the somatosensory cortex in cervical dystonia-decreased amplitudes of high-frequency oscillations.

OBJECTIVE: To determine whether patients with cervical dystonia have electrophysiological signs of disinhibition in the somatosensory cortex by recording high-frequency oscillations (HFOs) in somatosensory evoked potentials (SEPs). METHODS: HFOs were recorded in 13 patients and 10 age-matched control subjects, and the data were analyzed statistically by paired comparison and by Pearson's correlation. RESULTS: In patients with cervical dystonia, the early part of HFOs showed a significant decrease in amplitude, and the amplitude ratios of both early and late parts of HFOs/N20 potential were also significantly decreased. The amplitudes of HFOs and N20 potential were linearly correlated in the control subjects but not in dystonia patients. CONCLUSIONS: Patients with cervical dystonia may suffer from a disturbance of inhibition in the sensory cortex. This disturbance is reflected by decreased HFO amplitude, representing decreased activities of inhibitory interneurons in area 3b.

Adult↗
PubMed2004

Serial segmental duplications during primate evolution result in complex human genome architecture.

The human genome is particularly rich in low-copy repeats (LCRs) or segmental duplications (5%-10%), and this characteristic likely distinguishes us from lower mammals such as rodents. How and why the complex human genome architecture consisting of multiple LCRs has evolved remains an open question. Using molecular and computational analyses of human and primate genomic regions, we analyzed the structure and evolution of LCRs that resulted in complex architectural features of the human genome in proximal 17p. We found that multiple LCRs of different origins are situated adjacent to one another, whereas each LCR changed at different time points between >25 to 3-7 million years ago (Mya) during primate evolution. Evolutionary studies in primates suggested communication between the LCRs by gene conversion. The DNA transposable element MER1-Charlie3 and retroviral ERVL elements were identified at the breakpoint of the t(4;19) chromosome translocation in Gorilla gorilla, suggesting a potential role for transpositions in evolution of the primate genome. Thus, a series of consecutive segmental duplication events during primate evolution resulted in complex genome architecture in proximal 17p. Some of the more recent events led to the formation of novel genes that in human are expressed primarily in the brain. Our observations support the contention that serial segmental duplication events might have orchestrated primate evolution by the generation of novel fusion/fission genes as well as potentially by genomic inversions associated with decreased recombination rates facilitating gene divergence.

Animals↗
PubMed2004

[Somatosensory evoked potentials/fields--exploration of brain function].

We have summarized the history of electroencephalography(EEG) since 1875, when a paper by Richard Caton was published describing the first EEG recordings in animals. Somatosensory evoked potentials (SEPs) were recorded by George Dawson in 1951. Thereafter, SEPs were developed for clinical use with other evoked potentials such as auditory evoked potentials(VEPs). To understand evoked potentials, related mechanism of induction of far-fields-potentials(FFP) following stimulation of the median nerve has been discussed. SEPs consisted of P9, N9, N10, P11, N11, N13, P13, P14, N18, N20 and P20/P22. Scalp recorded P9 FFP arises from the distal portion of the branchial plexus as reflected by N9 stationary negative potential recorded over the stimulated arm. Cervical N11 and N13 arise from the root entry zone and dorsal horn, respectively. Scalp recorded P13, P14 and N18 FFP originate from the brainstem. In this communication, magnetoencephalography(MEG) and results of one of our recent studies on somatosensory evoked fields(SEFs) are also discussed. One of the important features of MEG is that magnetic signals detected outside the head arise mainly from cortical currents tangential to the skull. Since the net postsynaptic current follows the orientation of cortical pyramidal cells, the MEG signals mainly reflect activity of the fissural cortex, whereas radial current may remain undetected. In our study, we demonstrated SEFs elicited by compression and decompression of a subject's glabrous skin by a human operator. Their dipoles were tangentially oriented from the frontal lobe to parietal lobe.

Animals↗
PubMed2003

Intestinal aganglionosis associated with the Waardenburg syndrome: report of two cases and review of the literature.

The authors report two cases of the rare concurrence of intestinal aganglionosis and Waardenburg syndrome in Japanese infants. The patients were a 1-month-old girl and a 3-month-old boy at diagnosis, and both of them had either short segment or ultra-short segment aganglionosis. A review of 48 cases in the literature showed that the extent of the aganglionic segment is quite variable, from nearly total to ultra-short. The clinical features of aganglionosis in Waardenburg syndrome would appear to bear similarity in sex ratio and the extent of aganglionosis with those of Hirschsprung's disease associated with Ondine's curse, another type of neurocristopathy.

Comorbidity↗
PubMed2003

Genetics and genomics of behavioral and psychiatric disorders.

Psychiatric conditions are to some degree under genetic influences. Despite the application of advanced genetic and molecular biological technologies, the genetic bases of the human behavioral traits and psychiatric diseases remains largely unresolved. Conventional genetic linkage approaches have not yielded definitive results, possibly because of the absence of objective diagnostic tests, the complex nature of human behavior or the incomplete penetrance of psychiatric traits. However, recent studies have revealed some genes of interest using multifaceted approaches to overcome these challenges. The approaches include using families in which specific behaviors segregate as a mendelian trait, utilization of endophenotypes as biological intermediate traits, identification of psychiatric disease phenotypes in genomic disorders, and the establishment of mouse models.

Animals↗
PubMed2003

Severe localized stenosis and marked dilatation of the main pancreatic duct are indicators of pancreatic cancer instead of chronic pancreatitis on endoscopic retrograde balloon pancreatography.

BACKGROUND: Differentiation between benign and malignant localized stenoses of the main pancreatic duct is difficult by pancreatography. METHODS: A total of 48 patients with such localized stenosis who underwent endoscopic retrograde balloon pancreatography with abdominal compression were retrospectively studied. The following were examined: (1) diameter of the stenotic, prestenotic, and poststenotic ductal segments; (2) ratios of prestenotic/poststenotic, stenotic/prestenotic, and stenotic/poststenotic ductal segments; (3) length of stenosis and steepness of transition to the stenosis (proximal angle, distal angle); and (4) main duct and branch findings for peristenotic segments. RESULTS: The stenosis was diagnosed as caused by chronic pancreatitis in 27 patients and pancreatic cancer in 21 by histopathology, cytology, or clinical follow-up. The prestenotic/poststenotic ductal segments ratio and proximal angle were greater in pancreatic cancer compared with chronic pancreatitis. Severe stenosis (stenotic ductal segments less than 20% of prestenotic or poststenotic ductal segments); moderate (prestenotic ductal segments 2.5 to 3.5 times larger than poststenotic ductal segments), and severe (prestenotic ductal segments more than 3.5 times larger than poststenotic ductal segments) dilatation of the proximal duct were more frequent in pancreatic cancer than in chronic pancreatitis. Multivariate regression analyses showed that severe stenosis and dilatation were independently significant parameters that indicated a diagnosis of pancreatic cancer. Various combinations of severe stenosis, proximal dilatation, and double duct sign gave high predictive values. CONCLUSIONS: Severe stenosis, marked proximal dilatation, double duct sign, and combinations of these findings are useful indicators of malignant localized stenosis of the pancreatic duct.

Adult↗
PubMed2003

Reelin and disabled-1 expression in developing and mature human cortical neurons.

In developing mammalian (mouse) brain, Reelin (Reln) is secreted by the Cajal-Retzius (CR) neurons in the marginal zone, binds apolipoprotein E receptor 2 (ApoER2) and very low density lipoprotein receptor (Vldlr), and induces the phosphorylation of the downstream cytoplasmic molecule disabled-1 (Dab1) in cortical plate neurons. Although this is a well-characterized signaling pathway in mice, it has not been well defined in human brain. In this paper we examined the expression of RELN, APOER2, VLDLR, and DAB1 in the developing human brain by RT-PCR. We further determined the cellular expression of the proteins RELN and DAB1 in 50 human brains ranging in age from 10 gestational weeks (GW) to 62 years using immunochemistry. We found that the pattern of expression of RELN and DAB1 in the human brain isnot identical to that observed in the mouse brain. In particular, we report the novel finding that human DAB1and RELN are coexpressed in CR neurons during cortical development and in cortical pyramidal neurons after neuronal migration is complete. Thus, in the human brain, the whole RELN signaling pathway is present within selected populations of cortical neurons throughout life. We speculate that RELN and DAB1 coexpression in these neurons is necessary for both normal cortical development and mature function.

Adolescent↗
PubMed2002

Effects of movement on somatosensory N20m fields and high-frequency oscillations.

Somatosensory evoked fields were recorded to determine the effects of movement and attention on high-frequency oscillations during active finger movements of the ipsilateral and contralateral sides in response to electrical stimulation of the median nerve. A whole-scalp neuromagnetometer was used to record somatosensory evoked fields from eight subjects following electric median nerve stimulation at the wrist. The following three sessions were performed: (1). rest, (2). movement of fingers on the ipsilateral in response to stimulation and (3). movement of fingers on the contralateral in response to stimulation. The somatosensory evoked fields with a wide-bandpass (0.1-1000 Hz) were recorded. High-frequency oscillations and N20m were separated by subsequent high-pass (> 300 Hz) and low-pass (< 300 Hz) filtering. The maximum amplitude of high-frequency oscillations decreased during finger movements accompanying a decrease in somatosensory N20m dipole strength. Activation of the motor cortex appeared to suppress both the amplitude of high-frequency oscillations and the N20m dipole strength.

Adult↗
PubMed2002

Novel mutation in X-linked Charcot-Marie-Tooth disease associated with CNS impairment.

The authors describe a 16-year-old boy with severe muscular atrophy and signs of peripheral neuropathy compatible with Charcot-Marie-Tooth disease. Abnormalities in the cerebellum and central somatosensory pathway were also noted. Gene analysis revealed a novel gross insertion mutation in exon 2 of the connexin32 gene along with a 21-base pair duplication resulting in a seven-amino acid insertion in the first extracellular loop of the protein.

Adolescent↗
PubMed2002

Genomic rearrangements resulting in PLP1 deletion occur by nonhomologous end joining and cause different dysmyelinating phenotypes in males and females.

In the majority of patients with Pelizaeus-Merzbacher disease, duplication of the proteolipid protein gene PLP1 is responsible, whereas deletion of PLP1 is infrequent. Genomic mechanisms for these submicroscopic chromosomal rearrangements remain unknown. We identified three families with PLP1 deletions (including one family described elsewhere) that arose by three distinct processes. In one family, PLP1 deletion resulted from a maternal balanced submicroscopic insertional translocation of the entire PLP1 gene to the telomere of chromosome 19. PLP1 on the 19qtel is probably inactive by virtue of a position effect, because a healthy male sibling carries the same der(19) chromosome along with a normal X chromosome. Genomic mapping of the deleted segments revealed that the deletions are smaller than most of the PLP1 duplications and involve only two other genes. We hypothesize that the deletion is infrequent, because only the smaller deletions can avoid causing either infertility or lethality. Analyses of the DNA sequence flanking the deletion breakpoints revealed Alu-Alu recombination in the family with translocation. In the other two families, no homologous sequence flanking the breakpoints was found, but the distal breakpoints were embedded in novel low-copy repeats, suggesting the potential involvement of genome architecture in stimulating these rearrangements. In one family, junction sequences revealed a complex recombination event. Our data suggest that PLP1 deletions are likely caused by nonhomologous end joining.

Base Sequence↗