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T Kitamoto

Publications and source records attributed to T Kitamoto.

At least 73 records · Page 4Linked to original sources
PubMed1996

Mutation in the prion protein gene at codon 232 in Japanese patients with Creutzfeldt-Jakob disease: a clinicopathological, immunohistochemical and transmission study.

We describe the clinical, neuropathological, immunohistochemical and transmission findings in three patients with Creutzfeldt-Jakob disease (CJD) with a substitution from methionine to arginine at codon 232 (M232R) in the prion protein (PrP) gene. The patients with M232R presented clinically with rapidly progressive dementia, myoclonus, and periodic synchronous discharges in the electroencephalogram. These findings were mostly consistent with those for sporadic CJD. All patients reached the stage of akinetic mutism between 2 and 6 months, and died between 4 and 24 months after the onset of the disease. Histopathological examination revealed spongiform changes, neuronal loss and severe astrocytosis. Immunohistochemical staining for PrP showed diffuse gray matter staining, including synaptic structures. However, no plaque-type PrP deposition was observed in the affected brain tissue sections. The brain homogenates from two patients were successfully transmitted to experimental animals. Since the same mutation was not found in 100 healthy control individuals, the mutation might be associated with the disease. The clinicopathological and experimental transmission studies of CJD patients with this PrP gene mutation may thus help us to determine both phenotypic variations and the potential infectivities in different forms of prion diseases.

Aged↗
PubMed1996

Intron retention generates a novel isoform of the murine vitamin D receptor that acts in a dominant negative way on the vitamin D signaling pathway.

We identified and characterized a novel rat vitamin D receptor isoform (rVDR1), which retains intron 8 of the canonical VDR (rVDR0) during alternative splicing. In this isoform protein directed by the stop codon in this newly identified exon, a part of the ligand binding domain (86 amino acids) is truncated at the C-terminal end but contains 19 extra amino acids. The rVDR1 transcript was expressed at a level 1/15 to 1/20 of that of rVDR0 in the kidney and intestine in adult rats but not in embryos. The recombinant rVDR1 protein showed no ligand binding activity. Homo- and heterodimers of the recombinant rVDR0 and rVDR1 proteins bound to a consensus vitamin D response element (VDRE) but not to consensus response elements for thyroid hormone and retinoic acid. However, unlike rVDR0, rVDR1 did not form a heterodimeric complex with RXR on the VDRE. A transient expression assay showed that this isoform acted as a dominant negative receptor against rVDR0 transactivation. Interestingly, the dominant negative activities of rVDR1 differed among VDREs. Thus, the present study indicates that this new VDR isoform negatively modulates the vitamin D signaling pathway, through a particular set of target genes.

Alternative Splicing↗
PubMed1996

Differential expression of CD44 variants among meningioma subtypes.

Aims/background-CD44 is a widely distributed cell surface molecule which has numerous isoforms generated by alternative splicing. The diverse functions related to the CD44 variants (CD44v) have been reported in various physiological and pathological conditions. The pattern of expression of CD44v among meningioma subtypes was investigated to ascertain whether CD44 variants play a role in a variety of biological processes, such as epithelial differentiation and extracranial metastasis.Methods-Twenty three meningiomas were studied immunohistochemically using novel antibodies directed against CD44 isoforms. Six of the 23 samples were analysed by reverse transcription polymerase chain reaction (RT-PCR), followed by Southern blotting with CD44v specific probes.Results-In meningothelial, fibrous and anaplastic meningiomas, a standard form of CD44 was detected by RT-PCR and was homogeneously expressed in tumour cells when studied immunohistochemically. CD44v was not detected in these subtypes. In secretory meningiomas, however, CD44v isoforms were strongly expressed in the cell clusters that produce secretory granules and also accumulated in the granules. The population of tumour cells immunopositive for CD44v was similar to that which stained with antibodies directed against carcinoembryonic antigen, epithelial membrane antigen and ezrin. On RT-PCR with Southern blotting, only the secretory type showed high level expression of CD44v.Conclusions-CD44v in meningiomas is expressed in relation to tumour cell differentiation towards the epithelial type.

Journal Article↗
PubMed1996

Experimental transmission of Creutzfeldt-Jakob disease and related diseases to rodents.

Sporadic Creutzfeldt-Jakob disease (CJD) with 129M/M, and iatrogenic and familial CJD with E200K and M232R, showed similar clinicopathologic features, a synaptic type deposition of PrPCJD, and high transmission frequencies to mice. Sporadic patients with 129M/V or 129V/V, and mutation cases with V180I, showed slightly different features and low or null transmission frequencies to mice. Hereditary cases with P102L, P105L, A117V, Y145stop, and insertions had different features but all demonstrated a long clinical duration and the presence of PrP plaques. The experimental transmission to mice of these mutant forms was difficult, except for one-third of the cases with P102L. CJD and related diseases, even those that are hereditary, may thus be divided into two different groups, those that are easily transmissible and those that are either difficult to transmit or nontransmissible.

Adult↗
PubMed1996

Fatal familial insomnia with a mutation at codon 178 of the prion protein gene: first report from Japan.

Fatal familial insomnia (FFI), or familial selective thalamic degeneration with a mutation at codon 178 of the prion protein (PrP) gene, is a rapidly progressive autosomal dominant disease characterized by progressive insomnia, dysautonomia, and myoclonus. We report here the clinical and postmortem findings as well as genomic analysis in a first non-Western case with FFI. This patient also clinically had cognitive impairments such as memory disturbance, delirium, and hallucinations, along with insomnia, dysautonomia, and myoclonus. This case implies a worldwide distribution of FFI and also highlights the need for more aggressive clinical application of genomic analysis of the PrP gene and polysomnographic study in patients with insomnia and cognitive impairments.

Humans↗
PubMed1996

[A case of Creutzfeldt-Jakob disease (CJD) started with monoparesis of the left arm].

A 72-year-old man developed a sudden weakness in his left hand on October 5, 1991. He was admitted two weeks thereafter. Physical examination revealed minimal weakness, and clumsiness of the fingers on his left hand. Exaggerated tendon reflexes and spasticity were also noted only on his left upper limb. He had neither dementia nor psychiatric symptoms. Subsequently he developed weakness in his left leg on November 17. Within 12 days he developed left facial weakness, and myoclonic movements on the left side. By December 2, he developed spastic tetraparesis with bilateral facial palsy, and generalized myoclonic jerks. A few days after that he started to show decorticate posture. From December 16, his mental status deteriorated rapidly, and he became mute, and uncooperative within a week. His clinical course can be summarized as stepwise progression similar to a cerebrovascular accident. Electroencephalography was normal on admission, but periodic synchronous discharge developed in January 1992. Brain CT that showed only mild brain atrophy at first was considered to be compatible with his age, changed to have severe brain atrophy in March 1992. He died of pneumonia on May 24, 1992 after eight months of progressive clinical course. Autopsy was done. The brain weighed 930 grams. Macroscopically there was prominent cortical atrophy. Microscopic examination revealed severe spongy state throughout the cerebral cortex. Typical spongiform changes were confined to the hippocampus. The cerebral white matter appeared to be normal. In the cerebellar cortex, the granular cell layer disappeared and Purkinje's cells were reduced in number. Kuru plaques were not seen. The cerebellar white matter, dentate nucleus, and brainstem seemed to be normal. The spinal cord was not examined. There were no pathological changes to indicate cerebrovascular accident, except for a lacuna in the right basal ganglion and a small angionecrosis in the pons. Western blotting test using Anti-APC (amyloid plaque core) antibody was positive. Neuropathological changes of the present case were consistent with those of CJD. However, the sudden onset of monoparesis without dementia or ataxia is rare as the initial symptom of this disease. The subsequent clinical course with stepwise progression of hemiplegia, which was mimicking a progressive stroke, was also rare for CJD. In comparison to typical case of CJD, this case had a different clinical onset as acute monoparesis. We can find such cases of CJD presenting as stroke in 5.6% in the previous English literatures.

Aged↗
PubMed1996

[Prion diseases and a new variant of Creutzfeldt-Jakob disease].

The causal link of a new variant of CJD (v-CJD) with bovine spongiform encephalopathy (BSE) has led to world-wide panic. BSE emerged in 1986 through dietary products contaminated with scrapie pathogen, BSE case reports increased in number up to 37,000/year in 1993, then declined in 1994 when the first case of v-CJD emerged. There is a 3-year gap between the emergence of BSE and the introduction of a ban on the use of specified bovine offal in human food. People might have consumed dietary products contaminated with BSE pathogen for the period. Species barrier which has protected human from being transmitted with sheep scrapie pathogen might not work so well in cow-to-human transmission as in sheep-to-human. There are familial forms and sporadic forms of human prion diseases. The familial prion diseases are always related to prion protein (PrP) gene mutations. Sporadic forms of prion diseases are composed of sporadic CJD, iatrogenic CJD and kuru. Sporadic CJD occurs in elder people and shows cortical signs and periodic synchronous discharges (PSD) in short clinical course and pathologically spongiform degeneration and abnormal PrP deposition in synapse structures, but no amyloid plaque deposition in the brain is observed. Since the v-CJD patients had no mutations in PrP gene, v-CJD belongs to sporadic forms of prion diseases. v-CJD shows quite different clinicopathological features from those of sporadic CJD, rather shows similar features to iatrogenic CJD of pituitary hormone and kuru. These three diseases share several features, which are younger patient age, main clinical manifestation of cerebellar signs, negative or rare record of PSD, and PrP amyloid plaque deposition in the brain. The patients of v-CJD, however, had no history of exposure to iatrogenic factors and of cannibalism. Also they did not have a valine polymorphism at PrP codon 129 which is frequently observed in the patients with iatrogenic CJD and kuru. Thus, v-CJD is a quite novel entity in human prion diseases.

Animals↗
PubMed1995

Activation of the estrogen receptor through phosphorylation by mitogen-activated protein kinase.

The phosphorylation of the human estrogen receptor (ER) serine residue at position 118 is required for full activity of the ER activation function 1 (AF-1). This Ser118 is phosphorylated by mitogen-activated protein kinase (MAPK) in vitro and in cells treated with epidermal growth factor (EGF) and insulin-like growth factor (IGF) in vivo. Overexpression of MAPK kinase (MAPKK) or of the guanine nucleotide binding protein Ras, both of which activate MAPK, enhanced estrogen-induced and antiestrogen (tamoxifen)-induced transcriptional activity of wild-type ER, but not that of a mutant ER with an alanine in place of Ser118. Thus, the activity of the amino-terminal AF-1 of the ER is modulated by the phosphorylation of Ser118 through the Ras-MAPK cascade of the growth factor signaling pathways.

Amino Acid Sequence↗
PubMed1995

Immunocytochemical study of choline acetyltransferase in Drosophila melanogaster: an analysis of cis-regulatory regions controlling expression in the brain of cDNA-transformed flies.

We have analyzed the cis-regulatory regions in the 5' flanking DNA of the Drosophila melanogaster choline acetyltransferase (ChAT; E.C. 2.3.1.6) gene by using germline transformants. These transformants are carrying wild-type ChAT cDNA fused to different lengths of 5' flanking sequence of the ChAT gene. Appropriate genetic crosses were used to introduce the transgene into animals with a presumptive null genetic background for endogenous ChAT. Expression of ChAT protein could thus be attributed exclusively to the transgene. Using a monoclonal antibody against Drosophila ChAT, we have investigated the spatial distribution of transgenic ChAT and compared it to the normal distribution of ChAT protein in wild-type animals. The brains of 7.4 kb cDNA transformants showed a ChAT expression pattern similar to that of wild-type animals in the first- and second-order sensory neuropil but reduced expression in other highly ordered neuropil. Several lines that were transformed with 1.2 kb or 0.8 kb of 5' flanking DNA demonstrated relatively normal expression in sensory neuropil. In addition, these lines also showed ectopic expression in higher order neuropil. In the optic lobe, the expression pattern directed by 7.4 kb of 5' flanking DNA was very similar to that of wild-type ChAT expression. In contrast, 1.2 kb or 0.8 kb transformants showed reduced levels of expression and a more limited pattern of distribution in the optic lobe. Our results suggest that the 5' flanking DNA of the ChAT gene can be divided into several separable positive and negative regulatory regions, which define various subsets of cholinergic neurons in the nervous system.

Animals↗
PubMed1995

First experimental transmission of fatal familial insomnia.

Originally described by Lugaresi et al. in 1986 (ref. 1), fatal familial insomnia (FFI) is a rare inherited neurological disease characterized by the subacute progression of intractable insomnia and other autonomic abnormalities, cerebellar and pyramidal signs, myoclonus and dementia; neuropathologically, the major feature is severe neuronal loss with associated gliosis in the ventral and mediodorsal thalamic nuclei. The disease has been related to the group of spongiform encephalopathies by virtue of the presence of low levels of proteinase-resistant amyloid protein (PrPres) in the brain, and of a pathogenic single-allele mutation at codon 178 of the PRNP gene that encodes PrPres (refs 2, 5). Here we report the successful transmission of the disease to experimental animals, placing FFI within the group of infectious cerebral amyloidoses.

Amyloidosis↗
PubMed1995

Allelic variation of apolipoprotein E in Japanese sporadic Creutzfeldt-Jakob disease patients.

We analyzed apolipoprotein E (apo E) genotypes in 53 Japanese sporadic Creutzfeldt-Jakob disease (CJD) patients and 100 normal controls using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. The apo E allelic frequencies in Japanese sporadic CJD patients and our control population were as follows: epsilon 2, 6.6% versus 7.5%; epsilon 3, 82.1% versus 81.5%; epsilon 4, 11.3% versus 11.0%. The mean ages at onset in Japanese sporadic CJD patients were as follows: epsilon 3/epsilon 3, 63.8 years; epsilon 3/epsilon 4, 66.3 years; epsilon 2/epsilon 3, 68.6 years. These results indicate that there is no association between apo E genotype and sporadic CJD in Japan.

Alleles↗
PubMed1995

Regulation of choline acetyltransferase/lacZ fusion gene expression in putative cholinergic neurons of Drosophila melanogaster.

We have analyzed the distribution of putative cholinergic neurons in whole-mount preparations of adult Drosophila melanogaster. Putative cholinergic neurons were visualized by X-gal staining of P-element transformed flies carrying a fusion gene consisting of 5' flanking DNA from the choline acetyltransferase (ChAT) gene and lacZ reporter gene. We have previously demonstrated that cryostat sections of transgenic flies carrying 7.4 kb of ChAT 5' flanking DNA show reporter gene expression in a pattern essentially similar to the known distribution of ChAT protein. Whole-mount staining of these same flies by X-gal should thus represent the overall distribution of ChAT-positive neurons. Extensive staining was observed in the cephalic, thoracic, and stomodeal ganglia, primary sensory neurons in antenna, maxillary palps, labial palps, leg, wing, and male genitalia. Primary sensory neurons associated with photoreceptors and tactile receptors were not stained. We also examined the effects of partial deletions of the 7.4 kb fragment on reporter gene expression. Deletion of the 7.4 kb fragment to 1.2 kb resulted in a dramatic reduction of X-gal staining in the peripheral nervous system (PNS). This indicates that important regulatory elements for ChAT expression in the PNS exist in the distal region of the 7.4 kb fragment. The distal parts of the 7.4 kb fragment, when fused to a basal heterologous promoter, can independently confer gene expression in subsets of putative cholinergic neurons. With these constructs, however, strong ectopic expression was also observed in several non-neuronal tissues.

Acetylcholine↗
PubMed1995

Prion disease with 144 base pair insertion in a Japanese family line.

We describe an insert mutation in the prion protein (PrP) gene in a Japanese family line that encodes six octapeptide repeats. This is the second report to date of an inherited prion disease with a 144-base pair insertion, although the order of the repeat sequences differ from that reported for the disease in an English family line. The clinical features, like those of the English patients, were characterized by a slowly progressive generalized dementia with some neurological signs and cortical focal symptoms. Postmortem examination disclosed diffuse atrophy of cerebral gray matter and the cerebellar cortex; histologically, there were marked patchy and regional neuronal loss with astrocytosis in the frontal cortex, amygdala and hippocampus and PrP-immunoreactive plaques in the molecular layer of the cerebellum. These plaques were different from typical kuru plaques. The prion disease in the present Japanese family line is compared with that in the English family line.

Adult↗
PubMed1995

Localization of choline acetyltransferase-expressing neurons in the larval visual system of Drosophila melanogaster.

Choline acetyltransferase (ChAT) is the enzyme catalyzing the biosynthesis of acetylcholine and is considered to be a phenotypically specific marker for cholinergic neurons. We have examined the distribution of ChAT-expressing neurons in the larval nervous system of Drosophila melanogaster by three different but complementary techniques: in situ hybridization with a cRNA probe to ChAT messenger RNA, immunocytochemistry using a monoclonal anti-ChAT antibody, and X-gal staining of transformed animals carrying a reporter gene composed of 7.4 kb of 5' flanking DNA from the ChAT gene fused to a lacZ reporter gene. All three techniques demonstrated ChAT-expressing neurons in the larval visual system. In embryos, the photoreceptor organ (Bolwig's organ) exhibited strong cRNA hybridization signals. The optic lobe of late third-instar larvae displayed ChAT immunoreactivity in Bolwig's nerve and a neuron close to the insertion site of the optic stalk. This neuron's axon ran in parallel with Bolwig's nerve to the larval optic neuropil. This neuron is likely to be a first-order interneuron of the larval visual system. Expression of the lacZ reporter gene was also detected in Bolwig's organ and the neuron stained by anti-ChAT antibody. Our observations indicate that acetylcholine may be a neurotransmitter in the larval photoreceptor cells as well as in a first-order interneuron in the larval visual system of Drosophila melanogaster.

Animals↗
PubMed1995

Serial MRI in early Creutzfeldt-Jacob disease with a point mutation of prion protein at codon 180.

We report a 66-year-old woman with histologically diagnosed Creutzfeldt-Jacob disease (CJD), followed with MRI from an early clinical stage. MRI demonstrated expansion of the high cortical signal on T2-weighted images, which differs from previous MRI reports of CJD. This patient followed an atypical clinical course: 16 months had passed before she developed akinetic mutism, and periodic sharp waves had not been detected on EEG after 2 years in spite of her akinetic mutism. Brain biopsy showed primary spongiform changes in the grey matter, and a point mutation of the prion protein gene at codon 180 was discovered using polymerase chain reaction direct sequencing and Tth 111 I cutting. This is the first case with the point mutation of the codon 180 variant with an atypical clinical course and characteristic MRI findings.

Aged↗
PubMed1995

New variant prion protein in a Japanese family with Gerstmann-Sträussler syndrome.

We found novel variants in the open reading frame of the prion protein (PrP) gene in a family with Gerstmann-Sträussler syndrome (GSS). Codon 219Lys variant is a normal polymorphism which we found recently. Some GSS cases were identified with codon 102 mutation (proline to leucine) and codon 219Lys polymorphism. While two families had a codon 102 mutation and codon 219Lys polymorphism in different alleles, 4 patients in one family had both in the same allele. The clinicopathological features of these 4 patients were clearly different from previously reported GSS patients with codon 102 mutation. These cases should be reported as a new variant of GSS.

Adult↗