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Biomedical subjects

K Hashimoto

Publications and source records attributed to K Hashimoto.

At least 487 records · Page 27Linked to original sources

Quantitative in situ PCR assay of HTLV-1 infected cells in peripheral blood lymphocytes of patients with ATL, HAM/TSP and asymptomatic carriers.

We established an in situ PCR (IS-PCR) method that amplified the pX region of human T cell lymphotropic virus type 1 (HTLV-1) proviral DNA. The procedure was highly sensitive in accurately detecting the number of cells infected with HTLV-1. We estimated the number of HTLV-1 infected cells in peripheral blood lymphocytes (PBL) from patients with HAM/TSP, ATL and asymptomatic carriers. ATL patients (n = 5) had 8-93% IS-PCR positive cells for HTLV-1 and these percentages correlated with the clinical stages. Asymptomatic carriers (n = 3) had 0.8-3.8% (mean 1.1%, S.D. 1.7) positive cells. HAM/TSP patients (n = 10) had 3.1-8.5% (5.8% (5.8%, 2.7) positive cells. Patients with shorter duration of illness showed larger percentages compared with patients with longer duration. In one HAM/TSP patient, the number of IS-PCR positive cells decreased from 5.1% to 1.5% coincident with the times of lymphocytapheresis treatment. Our studies may suggest that an increased viral load initiates the pathogenic process of HAM/TSP and the estimation of HTLV-1 proviral load by IS-PCR method is useful to understand the clinical state of HAM/TSP.

Adult↗

Expression of fos protein in rat brain following administration of a nicotinic acetylcholine receptor agonist epibatidine.

Epibatidine (exo-2-(6-chloro-3-pyridyl)-7-azabicyclo-[2.2.1]heptane), an extract of frog skin, is a novel and highly potent agonist for the nicotinic acetylcholine (ACh) receptor. The present study was undertaken to examine the expression of Fos protein in several rat brain regions following an acute administration of epibatidine. Furthermore, we also studied the role of the dopamine D1 and D2 receptors and the N-methyl-d-aspartate (NMDA) receptor, and nicotinic ACh receptor in the expression of Fos protein by epibatidine. A single administration of epibatidine (5, 10, 50 microgram/kg) caused a marked induction of Fos-immunoreactivity in the prefrontal cortex, medial striatum, nucleus accumbens, amygdala and superior colliculus of rat brain. In these regions, pretreatment with SCH 23390 (1.0 mg/kg), a dopamine D1 receptor antagonist, MK-801 (1.0 mg/kg), a NMDA receptor antagonist, and mecamylamine (5. 0 mg/kg), a nicotinic Ach receptor antagonist, inhibited the induction of Fos protein by epibatidine (10 microgram/kg). Pretreatment with sulpiride, a dopamine D2 receptor antagonist, blocked the induction of Fos protein in the prefrontal cortex and the core region of accumbens nucleus, but not in the medial striatum and the shell division of nucleus accumbens of rat brain. These results suggest that epibatidine induced the expression of Fos protein in several regions of rat brain, and that dopamine D1 receptor, NMDA receptor, and nicotinic ACh receptor may play a role in the expression of Fos protein by epibatidine in rat brain. Furthermore, dopamine D2 receptor may, in part, play a role in epibatidine induced expression of Fos protein in the prefrontal cortex and the core region of nucleus accumbens, but not in the medial striatum and the shell division of nucleus accumbens of rat brain.

Animals↗

Existence of a bovine LINE repetitive insert that appears in the cDNA of bovine protein BCNT in ruminant, but not in human, genomes.

A novel protein, BCNT, originally isolated from bovine brain and named after Bucentaur, contains an internal portion that is translated from part of bovine LINE repetitive sequence (Bov-B LINE). Human cDNA highly homologous to the bovine bcnt (bbcnt) cDNA has been isolated but does not contain a sequence similar to the Bov-B LINE insert (Nobukuni, T., Kobayashi, M., Omori, A., Ichinose, S., Iwanaga, T., Takahashi, I., Hashimoto, K., Hattori, S., Kaibuchi, K., Miyata, Y., Masui, T., Iwashita, S., 1997. An Alu-linked repetitive sequence corresponding to 280 amino acids is expressed in a novel bovine protein, but not in its human homologue. J. Biol. Chem. 272, 2801-2807). In this study, we conducted a polymerase chain reaction analysis to investigate whether such a Bov-B LINE insert is present in bcnt orthologs in other animals and in the genomic sequence of the human BCNT (hBCNT) gene. The results indicate that the Bov-B LINE insert is present in the genomic sequences of bcnt orthologs from sheep, goats, axis deer, and mouse deer (chevrotain), that is in Ruminantia, but not in pigs or human. Analysis of the bbcnt genomic sequence around the Bov-B LINE insert revealed a large part of the inserted Bov-B LINE sequence to be included in an exon; this is followed by a 54-nucleotide sequence that is highly homologous to Bov-B LINE in the 3'-side intron. The hBCNT gene was isolated and found to consist of seven exons and six introns, among which the intron corresponding to the Bov-B LINE insertion site in the bbcnt genome is 16.5kb in length with no sequence similar to Bov-B LINE. Based on these results, it seems likely that the Bov-B LINE insert is derived from a long Bov-B LINE repetitive sequence transposed to an ancestral bcnt gene in Ruminantia and reformed as a new exon through new splicing sites in the transposed sequence.

Amino Acid Sequence↗

Systematic method to obtain novel genes that are regulated by mi transcription factor: impaired expression of granzyme B and tryptophan hydroxylase in mi/mi cultured mast cells.

The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). We have reported that the expression of several genes was impaired in cultured mast cells (CMCs) of mi/mi genotype, and demonstrated the involvement of MITF in the transcription of these genes. To obtain new genes whose transcription may be regulated by MITF, we prepared a subtracted cDNA library using +/+ and mi/mi CMCs. We found two clones carrying the granzyme (Gr) B and tryptophan hydroxylase (TPH) cDNAs in the subtracted library. The expression of the Gr B and TPH genes decreased in mi/mi CMCs, and recovered to nearly normal level by the overexpression of normal (+) MITF but not of mutant (mi) MITF. The +-MITF bound three and one CANNTG motifs in the Gr B and TPH promoters, respectively, and transactivated these two genes, indicating the involvement of +-MITF in their expression. Because TPH is the rate-limiting enzyme for serotonin synthesis, we examined the serotonin content of +/+ and mi/mi CMCs. The serotonin content was significantly smaller in mi/mi CMCs than in +/+ CMCs. The introduction of +-MITF but not of mi-MITF normalized the serotonin content in mi/mi CMCs.

Animals↗

Proteolysis of highly polysialylated NCAM by the tissue plasminogen activator-plasmin system in rats.

Tissue-type plasminogen activator (tPA), a serine protease which converts the zymogen plasminogen to the active protease plasmin, is believed to regulate neurite extension and neural cell migration by modulating extracellular metabolism. The highly polysialylated form of the neural cell adhesion molecule (NCAM-H) is strongly expressed in the developing brain and is believed to play a role in organizing the neural network. In this report, we incubated neonatal rat brain homogenates with human tPA and rat plasminogen in order to determine whether NCAM-H would be degraded. NCAM-H was degraded by plasmin which was formed from rat plasminogen by human tPA. The degradation was inhibited by the addition of plasminogen activator inhibitor type 1 (PAI-1) or aprotinin. These results suggest a possible contribution of the tPA-plasmin system to NCAM-H turnover in the developing brain.

Aging↗

A new variant translocation of t(15;17) in a patient with acute promyelocytic leukemia (M3): t(15;19;17)(q22;p13;q12).

The reciprocal translocation (15;17) is specifically associated with acute promyelocytic leukemia [APL; M3 subtype according to French-American-British (FAB) classification]. A few patients with this disease have complex variant translocations. We describe a patient with M3 carrying t(15;19;17)(q22;p13;q12), which is a new type of variant translocation. The karyotypic interpretation was confirmed by Southern blot analysis with the use of RAR alpha and by fluorescence in situ hybridization (FISH) with the use of painting probes of chromosomes 15, 17, and 19 and a (15;17) translocation DNA probe. The results support the idea that the key event in APL is the formation of fusion gene PML/RAR alpha on the der(15).

Adolescent↗

Cloning and chromosomal localization of a paralog and a mouse homolog of the human transaldolase gene.

A sequence homologous to the transaldolase gene (TALDO) was identified in a polymorphic cosmid DNA mapped on human chromosome 11p15 by exon trapping with pSPL3. Analysis of lambda clones contiguous to the cosmid clone showed that the related gene (TALDOR) consists of 8 exons spanning approximately 19kb from the translation start site to the polyadenylation signal. The exon sequence of TALDOR was almost identical with that of TALDO localized on 1p33-34. 1, but its exons corresponding to exons 4 and 5 of TALDO were found to be split by 4 introns in TALDOR. To examine the evolutionary conservation of two genes for transaldolase, we have isolated the cDNA for its mouse homolog and determined the nucleotide sequence covering the complete coding region. Fluorescence in situ hybridization using the cDNA as a probe showed that the mouse transaldolase gene (Taldo) is localized on chromosome 7 F3-F4 as a single copy gene. This chromosomal region is known to be syntenic to human chromosome 11p15 rather than to 1p33-p34.1, suggesting that TALDOR is the ancestral form. The existence of TALDOR implies a duplication of the mammalian transaldolase gene after divergence of rodent and primate.

Amino Acid Sequence↗

Molecular cloning, structural characterization, and chromosomal mapping of the human LECT2 gene.

We originally isolated LECT2 (leukocyte cell-derived chemotaxin 2) as a 16-kDa secreted protein having a human neutrophil chemotactic activity, then cloned human and bovine LECT2 cDNAs and demonstrated the liver-specific expression of the protein. LECT2 is thought to be a multifunctional protein, because it was recently found to be identical to chondromodulin-II a growth stimulator of chondrocyte cells. We report here the cloning and the structural analysis of the human LECT2 gene. The gene spans approximately 8 kb and consists of four exons and three introns. Primer extension analysis revealed that several transcription initiation sites occur within 70-230 nucleotides upstream of the translation initiation codon. Several transcriptional control sequences relevant to the liver-specific expression have been identified at the 5' untranslated region of the human LECT2 gene. The human LECT2 gene was mapped to chromosome 5q31.1-q32 by fluorescence in situ hybridization. This region contains a cluster of cytokine genes including IL-4, IL-5, and IL-9.

Base Sequence↗

Delayed onset of hemolytic anemia in CBA-Pk-1slc/Pk-1slc mice with a point mutation of the gene encoding red blood cell type pyruvate kinase.

The Pk-1slc gene encodes a mutant red blood cell (RBC) type pyruvate kinase (PK), and adult CBA-Pk-1slc/Pk-1slc mice show a severe nonspherocytic hemolytic anemia. However, the number of RBCs and the proportion of reticulocytes were comparable between neonatal CBA-Pk-1slc/Pk-1slc mice and control -+/+ mice. Since the age-dependent increase of RBCs was much greater in CBA-+/+ mice than in CBA-Pk-1slc/Pk-1slc mice, significant anemia was observed in the latter mice on day 14 after birth. The increase of RBCs in CBA-+/+ mice was due to the prolongation of their survival time. The half life of RBCs increased in CBA-+/+ mice with ages, but it decreased in CBA-Pk-1slc/Pk-1slc mice. The relatively longer half life of RBCs in neonatal CBA-Pk-1slc/Pk-1slc mice appeared to be due to the delayed switching from M2-type PK that are expressed by undifferentiated erythroid precursor cells to RBC-type PK that are expressed by mature RBCs.

Age of Onset↗

Distribution of cerebellar cortical lesions in multiple system atrophy: a topographic neuropathological study of three autopsy cases in Japan.

We investigated neuropathologically the distribution of the cerebellar cortical lesions in three Japanese autopsy cases of multiple system atrophy (MSA) using hemisphere specimens. The lesions were classified as mild, moderate or severe. The distribution of cerebellar cortical lesions in all three cases were uniform: the cerebellar cortical lesions were more conspicuous in the vermis than in the hemisphere. These neuropathological findings differ from the established theory that cerebellar lesions of MSA are more pronounced in the hemisphere than in the vermis. The degree of cerebellar cortical lesions in our cases increased in relation to the duration of the disease. Our pathological data may contribute to the morphological differential diagnosis in various neurodegenerative disorders including late cortical cerebellar atrophy. Our neuropathological findings may also make a contribution to the neuroradiological progress in the differential diagnosis of spinocerebellar disease.

Brain Mapping↗

Structural and phylogenetic analyses of RGD-CAP/beta ig-h3, a fasciclin-like adhesion protein expressed in chick chondrocytes.

A cDNA for RGD-CAP/beta ig-h3 was cloned from a chick embryo chondrocyte cDNA library. The deduced amino acid sequence showed that the chick RGD-CAP/beta ig-h3 is 76-77% identical with human, mouse and pig forms of the protein, and 43% identical with human and mouse osteoblast specific factor 2 (OSF2). RGD-CAP/beta ig-h3 contained four internal repeat domains and two highly conserved sequences (H1 and H2) in each repeat. Chick RGD-CAP/beta ig-h3, as well as the mammalian RGD-CAP/beta ig-h3, contained an RGD sequence, which may serve as a recognition sequence for integrins, in the fourth repeat. Database searches revealed that the H1 and H2 sequences are conserved in some secreted or membrane proteins of several species including mammals, insects, sea urchins, plants, yeast and bacteria. Phylogenetic analysis showed that a portion of the common ancestor gene for RGD-CAP/beta ig-h3 and OSF2 was duplicated to form four repeat domains before the separation of the genes followed by the divergence of vertebrate species.

Amino Acid Sequence↗

A nitric oxide donor NOC 7 suppresses renal responses induced by norepinephrine and angiotensin II in the NO-depleted denevated rabbit kidney.

Intrarenal arterial infusion of norepinephrine (30 ng/kg per min) or of angiotensin II (4 ng/kg per min) reduced the glomerular filtration rate and urinary Na+ excretion in denervated kidneys of anesthetized rabbits pretreated intrarenally with a nitric oxide (NO) synthase inhibitor N(omega)-nitro-L-arginine methyl ester (50 microg/kg per min). Angiotensin II but not norepinephrine reduced fractional Na+ excretion. Intrarenal administration of a spontaneous NO donor 1-hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene (NOC 7, 30 ng/kg per min) in L-NAME pretreated kidneys did not affect basal values, but attenuated the reduction in urinary Na+ excretion induced by these agonists without affecting the angiotensin II-induced reduction in glomerular filtration rate. The results suggest that NOC 7 can suppress the norepinephrine-induced hypofiltration and the angiotensin II-evoked tubular reabsorption and thereby attenuates the agonist-induced antinatriuresis in the denervated and endogenous NO-depleted rabbit kidney.

Angiotensin II↗

Gain-of-function mutations of c-kit in human gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the human digestive tract, but their molecular etiology and cellular origin are unknown. Sequencing of c-kit complementary DNA, which encodes a proto-oncogenic receptor tyrosine kinase (KIT), from five GISTs revealed mutations in the region between the transmembrane and tyrosine kinase domains. All of the corresponding mutant KIT proteins were constitutively activated without the KIT ligand, stem cell factor (SCF). Stable transfection of the mutant c-kit complementary DNAs induced malignant transformation of Ba/F3 murine lymphoid cells, suggesting that the mutations contribute to tumor development. GISTs may originate from the interstitial cells of Cajal (ICCs) because the development of ICCs is dependent on the SCF-KIT interaction and because, like GISTs, these cells express both KIT and CD34.

Amino Acid Sequence↗

The second subunit of DNA polymerase III (delta) is encoded by the HYS2 gene in Saccharomyces cerevisiae.

DNA polymerase III (delta) of Saccharomyces cerevisiae is purified as a complex of at least two polypeptides with molecular masses of 125 and 55 kDa as judged by SDS-PAGE. In this paper we determine partial amino acid sequences of the 125 and 55 kDa polypeptides and find that they match parts of the amino acid sequences predicted from the nucleotide sequence of the CDC2 and HYS2 genes respectively. We also show by Western blotting that Hys2 protein co-purifies with DNA polymerase III activity as well as Cdc2 polypeptide. The complex form of DNA polymerase III activity could not be detected in thermosensitive hys2 mutant cell extracts, although another form of DNA polymerase III was found. This form of DNA polymerase III, which could also be detected in wild-type extracts, was not associated with Hys2 protein and was not stimulated by addition of proliferating cell nuclear antigen (PCNA), replication factor A (RF-A) or replication factor C (RF-C). The temperature-sensitive growth phenotype of hys2-1 and hys2-2 mutations could be suppressed by the CDC2 gene on a multicopy plasmid. These data suggest that the 55 kDa polypeptide encoded by the HYS2 gene is one of the subunits of DNA polymerase III complex in S.cerevisiae and is required for highly processive DNA synthesis catalyzed by DNA polymerase III in the presence of PCNA, RF-A and RF-C.

Amino Acid Sequence↗

Presynaptic origin of paired-pulse depression at climbing fibre-Purkinje cell synapses in the rat cerebellum.

1. Climbing fibre-mediated excitatory postsynaptic potentials (CF-EPSPs) or currents (CF-EPSCs) were recorded from Purkinje cells in rat cerebellar slices using the whole-cell recording technique. 2. Climbing fibre responses displayed prominent paired-pulse depression (PPD). In the current-clamp recording mode, PPD resulted in a decreased number of spikelets in the second complex spike of the pair, and depression of the after-depolarization and after-hyperpolarization. 3. The mechanism of PPD was examined under voltage clamp. Manipulations that reduce transmitter release significantly affected PPD. These included lowering extracellular Ca2+ concentration and bath application of baclofen or adenosine. 4. Changing the number of stimulated climbing fibres, equivalent to changing the number of release sites, had no effect on PPD. 5. Selective manipulations of postsynaptic responsiveness had no effect on PPD. These included partial blockade of CF-EPSCs by a non-NMDA receptor antagonist, 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX), and changing the holding potential. 6. A rapidly dissociating AMPA receptor antagonist, 2,3-cis-piperidine dicarboxylic acid, inhibited the second CF-EPSC of the pair proportionately more than the first, suggesting that presynaptic release by the second pulse is decreased. 7. PPD at interstimulus intervals of 50 ms or longer (up to 3000 ms) was not significantly affected by manipulations that change postsynaptic glutamate receptor desensitization. 8. Blockade of metabotropic glutamate, GABAB and adenosine receptors had no effect on PPD, suggesting that presynaptic autoreceptors do not contribute to PPD. 9. These results indicate that decreased transmitter release is a major cause of PPD at cerebellar climbing fibre-Purkinje cell synapses.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

Severe hypersensitivity syndrome due to sulfasalazine associated with reactivation of human herpesvirus 6.

BACKGROUND: A severe adverse reaction to sulfasalazine therapy has been associated with hypersensitivity syndrome, the clinical features of which are similar to infectious mononucleosis. No serologic evidence of viral infections has been reported with this syndrome; however, human herpesvirus 6 infection has not been specifically investigated, which could cause an infectious mononucleosislike syndrome. OBSERVATIONS: We report 2 cases of hypersensitivity syndrome induced by the use of sulfasalazine. The clinical features of the syndrome appeared 18 and 32 days after administration of sulfasalazine. Clinical signs included a maculopapular rash progressing to exfoliate erythroderma, fever, and lymphadenopathy. Leukocytosis, atypical lymphocytes, liver dysfunction, and renal disturbance were also observed. In 1 patient, human herpesvirus 6 variant B was isolated from peripheral blood mononuclear cells, and in both patients anti-human herpesvirus 6 IgG titers increased considerably. CONCLUSIONS: Two cases of hypersensitivity syndrome due to sulfasalazine use were associated with the reactivation of human herpesvirus 6, which may be a required cause of hypersensitivity syndrome.

Adult↗

A new congenital muscular dystrophy with mitochondrial structural abnormalities.

We report a new form of congenital muscular dystrophy (CMD) in 4 patients from three unrelated families with probable autosomal-recessive inheritance. All patients had the clinical characteristics of merosin-positive congenital muscular dystrophy, but had marked mental retardation. The disease was slowly progressive and 1 patient died from dilated cardiomyopathy at the age of 13 years. In addition to dystrophic changes with necrosis and regeneration in muscle, the most striking finding was mitochondrial depletion in the center of the sarcoplasm. Mitochondria at the periphery of fibers were markedly enlarged ("megaconial" appearance) with complicated cristae, and contained a normal amount of mitochondrial DNA by in situ hybridization. Mitochondrial enlargement may represent functional compensation for mitochondrial depletion in the central sarcoplasm, where myofibrillar degeneration occurred.

Adolescent↗