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Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 19 recordsLinked to original sources
PubMed1997

T-cell subset-specific expression of the IL-4 gene is regulated by a silencer element and STAT6.

During development of CD4+ T lymphocytes in the periphery, differential expression of cytokine genes, such as those of interleukin (IL)-2 and IL-4, occurs in distinct T-cell subsets. IL-4 is a cytokine produced by T-helper 2 (Th2) cells, and the IL-4 receptor (IL-4R)-mediated signaling pathway is thought to be required for commitment to the Th2 phenotype. However, the molecular basis for development of the Th subset-specific production of IL-4 remains unclear. We demonstrate here that the IL-4 promoter is functional in Th1 and B cells which do not normally form IL-4 transcripts as well as in IL-4-producing T cells. Based on studies of the effect of several different upstream and downstream regions of the IL-4 gene on IL-4 promoter activity, a Th1-specific IL-4 silencer element was identified in the 3'-untranslated region. The silencer region contained a consensus sequence for a transcriptional factor that is normally regulated by the IL-4 R signaling pathway, STAT6. Nuclear expression of STAT6 protein, which was shown to bind to the silencer region, was observed in Th2 cells but not in Th1 cells. Deletion of the STAT6-binding site from the silencer region and inhibition of STAT6 function resulted in the appearance of silencing function even in Th2 cells. These results provide evidence that the silencer element, and the binding of STAT6 to this element, play a permissive role in determining the commitment into Th2 phenotype.

Animals↗
PubMed1997

Structural features of the gene encoding human muscle type carnitine palmitoyltransferase I.

We isolated a human muscle type of carnitine palmitoyltransferase I (CPTI-M) genomic clone and determined its entire nucleotide sequence. By comparison of the nucleotide sequence of the genomic clone with that of cDNA, we determined the intron/exon junctions. For detection of the exon(s) in the 5'-region of the CPTI-M gene, we isolated cDNA clones corresponding to the 5'-region of its transcript by 5'-rapid amplification of cDNA ends (5'-RACE method). Results showed two alternative exons, 1A and 1B, that do not encode amino acids in the 5'-region of the human CPTI-M gene. The gene encoding human CPTI-M was found to consist of two 5'-non-coding exons, 18 coding exons and one 3'-non-coding exon spanning approximately 10 kbp. Furthermore, on analysis of the 5'-flanking region, a putative gene encoding a 'choline kinase homologue' was found to be located only about 300 bp upstream from exon 1A of the human CPTI-M gene. Comparison of the gene structure of human CPTI-M with the reported partial gene structure of human liver type CPTI (CPTI-L) showed that the intron insertion sites were completely conserved in these two genes.

Amino Acid Sequence↗
PubMed1997

Effect of dibutyryl cyclic AMP on axoplasmic transport in the hippocampus.

The effect of dibutyryl cyclic AMP (dbcAMP) on axoplasmic transport of cultured hippocampal neuron cells from postnatal 1-day mice was analyzed with a computer-assisted video-enhanced differential interference contrast microscope system. Dibutyryl cyclic AMP increased the axoplasmic transport in both anterograde and retrograde directions. The number of particles flowing in the neurites was increased by 0.5 mM dbcAMP. The peak reached about 160% of the initial value. The instantaneous velocity of axoplasmic transport was also increased by 0.5 mM dbcAMP. The average velocity of anterograde and retrograde direction changed respectively from 1.95 +/- 1.01 microm/s (n = 55) to 2.66 +/- 1.26 microm/s (n = 58) and from 1.94 +/- 0.85 (n = 57) to 2.39 +/- 0.93 (n = 57). Rates were 136.1 and 123.1%, respectively. Previously, we have found that acetylcholine suppressed and adrenaline increased the axoplasmic transport in superior cervical ganglion cells. These effects are related to the amount of endogeneous cAMP. The results of the present report suggest that endogeneous cAMP is also related to hippocampal axoplasmic transport.

Animals↗
PubMed1997

A target of phosphatidylinositol 3,4,5-trisphosphate with a zinc finger motif similar to that of the ADP-ribosylation-factor GTPase-activating protein and two pleckstrin homology domains.

We have purified a protein that binds phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] using beads bearing a PtdIns(3,4,5)P3 analogue. This protein, with a molecular mass of 43 kDa, was termed PtdIns(3,4,5)P3-binding protein. The partial amino acid sequences were determined and a full-length cDNA encoding the protein was isolated from bovine brain cDNA library. The clone harbored an open reading frame of 373 amino acids which contained one zinc finger motif similar to that of ADP-ribosylation-factor GTPase-activating protein and two pleckstrin homology domains. The entire sequence was 83% similar to centaurin alpha, another PtdIns(3,4,5)P3-binding protein. The protein bound PtdIns(3,4,5)P3 with a higher affinity than it did inositol 1,3,4,5-tetrakisphosphate, phosphatidylinositol 4,5-bisphosphate, phosphatidylinositol 3,4-bisphosphate, and phosphatidylinositol 3-phosphate suggesting that the binding to PtdIns(3,4,5)P3 was specific. The binding activity was weaker in the mutants with a point mutation in the conserved sequences in each pleckstrin homology domain. Introduction of both mutations abolished the activity. These results suggest that this new binding protein binds PtdIns(3,4,5)P3 through two pleckstrin domains present in the molecule.

ADP-Ribosylation Factors↗
PubMed1997

Action mechanism of retinoid-synergistic dibenzodiazepines.

4-[5H-2,3-(2,5-Dimethyl-2,5-hexano)-5-methyldibenzo[b,e][1,4 ]diazepin-11-yl]benzoic acid (HX600), as well as its oxa- (HX620) and thia- (HX630) analogs, enhanced the activity of retinoic acid and a receptor alpha (RAR alpha)-selective agonist Am80 in HL-60 cell differentiation assays. HX600 synergizes with Am80 by binding to, and transactivating through, the RXR subunit of the RXR-RAR heterodimer. HX600 exhibited RXR pan-agonist activity in transient transfections with a DR1-based reporter gene and synergized with RA-bound RAR alpha and RAR beta in inducing transcription from a DR5-based reporter. In addition, all three compounds at high concentrations acted as RAR pan-antagonists in stably transfected RAR "reporter cells." These efficient synergists bind only weakly with RXRs in vitro, suggesting that they are RXR-RAR heterodimer-selective activators. These HX retinoids exhibited dual functionality, since they affected signalling through both retinoid receptor families (RARs and RXRs).

Benzoates↗
PubMed1997

Purification and characterization of low density lipoprotein containing apolipoprotein B-48 from the plasma of an apoE-deficient patient.

The plasma low density lipoprotein (LDL) of an apolipoprotein (apo) E-deficient patient was reported to contain apoB-48 (D. Kurosaka et al., Atherosclerosis 1988;88:15), which is a structural protein of chylomicrons and is not present in the fasting plasma LDL of normal subjects. We separated the LDLs containing apoB-48 (apoB-48 LDL) and apoB-100 (apoB-100 LDL) from the plasma of this patient using heparin-sepharose column chromatography. The apoB-48 LDL contained apoA-I, apoA-IV, and apoCs besides apoB-48. There were no differences in size and lipid composition of the apoB-48 and the apoB-100 LDLs, both of which contained more triglyceride than LDL from normal subjects. After incubation with apoE, the apoB-48 LDL contained twice the amount of apoE than the apoB-100 LDL and showed a marked decrease in apoA-I and apoA-IV content. These results suggest that lipoproteins containing apoB-48 in normal subjects can be quickly taken up through an apoE-mediated receptor mechanism after receiving apoE in exchange for apoA-I and A-IV.

Apolipoprotein B-100↗
PubMed1997

Dynamical analysis of schizophrenia courses.

In order to assess the working hypothesis that schizophrenia may be viewed as a nonlinear dynamical disease, we examined the long-term psychoticity dynamics of 14 patients. The data consist of daily ratings of psychopathology observed for 200 or more consecutive days in each patient. We implemented nonlinear dynamical analysis methods with a potential of being applicable even to relatively short and noisy time series: two different forecasting approaches combined with surrogate methods that allow statistical testing in each single case. The resulting classification of dynamics gives evidence that eight patients show nonlinear evolutions of symptom courses. Four cases can be modeled linearly, two as random processes. Thus, a larger proportion of the schizophrenic psychoses we studied shows nonlinear time courses. In this way the validity of the concept of dynamical diseases could be supported on statistical grounds in this important area of psychopathology. The nonlinear view-a low-dimensional nonlinear system generating psychotic symptoms--may provide the foundation for a more parsimonious theory of schizophrenia compared to traditional multicausal models. In several of the nonlinear cases we also observed the qualitative "fingerprint" of deterministic chaos: a decay of deterministic features of the course of disorder with time.

Adolescent↗
PubMed1997

Inhibition of IL-1-induced IL-6 production by synthetic retinoids.

The effects of retinoids and retinoid antagonists on IL-6 production in MC3T3-E1 cells were investigated. None of the synthetic retinoids examined stimulated IL-6 production, but all of them strongly inhibited IL-6 production induced by mouse IL-1 alpha. Their inhibitory activities correlated well with their differentiation-inducing activities in HL-60 assay or their binding affinities to nuclear retinoic acid receptors (RARs). Among three retinoid antagonists, two weak antagonists exhibited similar inhibition of mouse IL-1 alpha-induced IL-6 production, whereas a potent retinoid antagonist, 4-(13H-10,11,12,13-tetrahydro-10,10,13,13,15-pentamethyl-dinaph tho[2,3-b] [1,2-e]diazepin-7-yl)benzoic acid (LE540, 14), enhanced IL-6 production under the same conditions.

3T3 Cells↗
PubMed1997

Alternative expression of platelet glycoprotein Ib(beta) mRNA from an adjacent 5' gene with an imperfect polyadenylation signal sequence.

Glycoprotein (GP) Ib is a major component of the platelet membrane receptor for von Willebrand factor, designated the GP Ib-IX-V complex. GP Ib is composed of two subunits (GP Ib(alpha) and GP Ib(beta)) each synthesized from separate genes. The 206 amino acid precursor of GP Ib(beta) is synthesized from a 1.0-kb mRNA expressed by megakaryocytes and was originally characterized from cDNA clones of human erythroleukemic (HEL) cell mRNA, a cell line exhibiting megakaryocytic-like properties. The cell line CHRF-288-11 also exhibits megakaryocytic-like properties, but synthesizes two related GP Ib(beta) mRNA species of 3.5 and 1.0 kb. We performed cDNA cloning experiments to identify the origin of the 3.5-kb transcript and determine its relationship to the 1.0-kb GP Ib(beta) mRNA found in megakaryocytes, platelets, and HEL cells. Our cloning experiments demonstrate that the longer transcript results from a nonconsensus polyadenylation recognition sequence, 5'AACAAT3', within a separate gene located upstream to the platelet GP Ib(beta) gene. In the absence of normal polyadenylation the more 5' gene uses the polyadenylation site within its 3' neighbor, the platelet GP Ib(beta) gene. This newly identified 5' gene contains an open reading frame encoding 369 amino acids with a high degree of sequence similarity to an expanding family of GTP-binding proteins.

Amino Acid Sequence↗
PubMed1997

Isolation of a novel Sry-related gene that is expressed in high-metastatic K-1735 murine melanoma cells.

To identify genes differentially expressed in association with metastatic potential of K-1735 mouse melanoma cells, the mRNA differential display method was applied to compare mRNAs from high- and low-metastatic K-1735 cells. A novel gene was identified as being expressed in high-metastatic cells but not in low-metastatic cells. Sequence analysis revealed that this gene had an open reading frame of 538 amino acid residues containing a Sry high-mobility group (HMG) box domain, known as a DNA binding motif, particularly in the Sox family genes. This gene showed the highest homology to the human SOX9 gene, which is the responsible gene for an inherited disease, campomelic dysplasia. Thus, this gene was designated the Sox21 gene (the 21st Sox family gene). The Sox21 gene was mapped to mouse Chromosome 15, to which neither genes containing the HMG box region nor the loci of hereditary diseases similar to campomelic dysplasia have been previously mapped. This gene was highly conserved and specifically expressed in the brain. These results suggest that expression of the Sox21 gene is involved in the development of nerve systems and may function to enhance the metastatic potential of K-1735 mouse melanoma cells of nerve cell origin.

Amino Acid Sequence↗
PubMed1997

Quaternary structure-dependent idiotope and antigen binding of a monoclonal antibody specific for conformational epitope on type II collagen.

We previously generated a monoclonal antibody (mAb) against a putative pathogenic epitope on native type II collagen (CII) for the induction of collagen-induced arthritis in mice (mAb1), and an anti-idiotypic mAb which appears to possess the internal image of the CII epitope (mAb2). In the present study, the structural basis of the antigen/mAb1 and mAb1/mAb2 interactions was examined. When partially SH-reduced mAb1 was analysed on Western blots, only fragments containing both heavy (H) and light (L) chains were recognized by mAb2. When mAb2 was partially SH-reduced, only fragments containing both H and L chains were recognized by mAb1. H and L chains were separated from mAb1 in a reduced, denatured condition, and each chain and a mixture of the two were refolded. mAb2 reacted specifically to the renatured whole IgG molecule of mAb1, but not to the refolded L or to H chains. Recombinant single chain Fv (scFv) generated from mAb1 and mAb2 had properties of the original mAbs, whereas genetically constructed chimeric scFvs, consisting of VH from mAb1 and an irrelevant VL. or VL of mAb1 and an irrelevant VH. did not react either to CII or to mAb2. Thus, interactions among CII, mAb1 and mAb2 appear to depend on quaternary structures containing different protein subunits. These observations support the internal image property of the mAb2. In addition, this dependency on quaternary structure for recognition of proteins may also be relevant to other protein-protein interactions.

Amino Acid Sequence↗
PubMed1997

RT1.P, rat class Ib genes related to mouse TL: evidence that CD1 molecules but not authentic TL antigens are expressed by rat thymus.

CD1 and TL were once thought to be genetic homologues because of their thymus-specific expression. We investigated their equivalents in the rat to clarify whether their structure and pattern of expression are conserved in rodents. Two rat class Ib genes, containing 3' sequences very similar to mouse TL, were identified and designated RT1.P. Neither of them, however, can encode ordinary class I molecules due to the accumulation of harmful mutations in the 5' regions that are unique to RT1.P, while the 3' TL-like regions still retain protein-coding capacity. Comparison of the structural organization of three types of TL family genes, which include mouse T3/T18-encoding TL antigens, mouse T1/T16, and rat RT1. P1/P2 pseudogenes, revealed the presence of a clear demarcation between the type-specific and TL-specific sequences at intron 3. This finding suggests that recombination plays an important role in creating the TL family genes in rodents. Characteristic features of TL, such as a low level of polymorphism and linkage to the major histocompatibility complex, were also observed in the rat. On the other hand, rat CD1 molecules were expressed at a high level on the surface of thymocytes. Absence of authentic TL antigens and thymic expression of CD1d molecules in the rat suggest the plasticity and conservation of class Ib genes in rodent evolution. Functions of TL may be substituted with CD1 or other class Ib molecules expressed by rat thymus.

Amino Acid Sequence↗
PubMed1997

The Propionibacterium freudenreichii hemYHBXRL gene cluster, which encodes enzymes and a regulator involved in the biosynthetic pathway from glutamate to protoheme.

A clone that can complement both Escherichia coli hemB and hemL mutations was found among plasmids containing the Propionibacterium freudenreichii hemB gene, which encodes delta-aminolevulinic acid dehydratase. The regions upstream and downstream of the hemB gene were sequenced. Two open-reading frames (ORF1 and -2), which were similar to the hemY gene encoding protoporphyrinogen oxidase and the hemH gene encoding ferrochelatase from Bacillus subtilis, were found upstream of the hemB gene. ORF1 and -2 complemented the E. coli hemG mutation, defective in protoporphyrinogen oxidase, and the hemH gene respectively. Since ORF1 had no homology to hemG, the gene was designated hemY. The hemYHB genes appeared to be within the same transcription unit. Downstream from the hemB gene, three open-reading frames were found. One of these, transcribed in the same direction as the hemB gene, was identical to be the hemL gene, which encodes glutamate-1-semialdehyde 2,1-aminomutase. The other two open-reading frames, located between the hemYHB and hemL genes, were transcribed divergently, and their deduced amino acid sequences showed similarities to a membrane-bound transport protein and a transcriptional regulatory protein respectively. The two genes may thus be involved in hem transport and the regulation of hem gene expression respectively, and were tentatively named hemX and hemR. Although hemX and hemL are unlikely to be part of the same operon, hemYHBXRL are clustered on the P. freudenreichii chromosome.

Amino Acid Sequence↗
PubMed1997

Specific detection of kappa light chain in uric acid stones.

Proteins were extracted from uric acid stones with 6M guanidine chloride (pH 8.5), which were successively developed by 12% polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE). Amino acid sequence analysis of each band on SDS-PAGE revealed that major components in uric acid stones were immunoglobulin alpha heavy and kappa light chains. Although immunoglobulin heavy chain (gamma and mu, as well as alpha) and a kappa light chain were clearly detected in uric acid stones by Western blotting using their specific antibodies, no lambda chains whatsoever could be detected. The results suggest that immunoglobulins selectively containing kappa light chain might have specific functions in uric acid stone formation as stone matrices.

Amino Acid Sequence↗
PubMed1997

Preference of peanut agglutinin labeling for long-wavelength-sensitive cone photoreceptors in the dace retina.

Peanut agglutinin (PNA) was known for its selective binding to cone cells. In the present study, we investigated whether there was any difference in PNA binding among various subtypes of cone photoreceptor cells in the dace retina. The outer segments of the long-double- and long-single-cone cells were preferentially labeled with PNA. Ultrastructural pre-embedding labeling revealed that the binding sites of PNA were confined to the calycal processes of these cells. By contrast, only slight labeling was discerned on the corresponding regions of other types of cone cells. The results indicate that PNA can distinguish the long-wavelength-sensitive cone from the short-to-middle-wavelength-sensitive cone cells.

Animals↗
PubMed1997

Postnatal development of B lymphocytes and immunoglobulin-containing plasma cells in the chicken oviduct: studies on cellular distribution and influence of sex hormones.

Postnatal development of B lymphocytes and plasma cells containing different classes of immunoglobulins (IgG, IgA, and IgM) was immunohistochemically studied in the oviduct of the Dekalb strain of the White Leghorn chicken. B lymphocytes first appeared in the lamina propria of the chicken oviduct at 5 weeks of age. Their frequency of occurrence peaked at 15 weeks from the infundibulum to the uterus (glandular part), while in the vagina (aglandular part) it did so at 21 weeks. Intraepithelial B lymphocytes were very rare and exclusively located in the vagina at 19 and 21 weeks. Plasma cells first appeared in the lamina propria of the oviduct at 11 weeks of age, and this frequency peaked at 32 weeks. IgG-containing plasma cells were most numerous in the glandular part, whereas in the aglandular part IgA and IgM cells were more numerous than IgG cells. When 7-day-old-chickens were treated with sex hormones, B lymphocytes and plasma cells appeared 12 h and 5 days after the hormone injection, respectively. Their frequency of occurrence was statistically higher in diethylstibestrol (DES)-treated chickens than in DES plus progesterone-treated chickens. This suggests that the postnatal development of B lymphocytes and plasma cells in the oviduct of the chicken is correlated to estrogen secretion.

Animals↗
PubMed1997

Elevated plasma levels of interleukin-6, interleukin-8, and granulocyte colony-stimulating factor during and after major abdominal surgery.

STUDY OBJECTIVE: To evaluate the influence of major abdominal surgery on the plasma levels of inflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8) and granulocyte colony-stimulating factor (G-CSF). DESIGN: Prospective study. SETTING: University hospital. PATIENTS: 10 ASA physical status I and II patients undergoing upper abdominal surgery. INTERVENTIONS: All patients received combined general-epidural anesthesia with isoflurane and nitrous oxide, after insertion of an epidural catheter at T7-T9 dosed with 1.5% lidocaine. MEASUREMENTS AND MAIN RESULTS: Plasma cytokine (IL-6, IL-8, G-CSF) levels were determined with an enzyme-linked immunosorbent assay (ELISA) at pre-anesthesia, 0, 2, and 4 hours during surgery, and at the end of surgery, followed by sampling on the morning of postoperative days 1 (POD1) and 3 (POD3). Plasma cortisol levels were also determined. The plasma levels of IL-6 increased gradually after skin incision and reached the maximal value at the end of surgery (p < 0.001). IL-8 levels also increased from the baseline value to their maximum at the end of surgery (p < 0.05). G-CSF levels were elevated from the pre-anesthesia value to their maximum by the end of operation (p < 0.005). Plasma cortisol levels were increased after skin incision (p < 0.001). Postoperative cytokine levels correlated significantly with each other (r = 0.68, p < 0.05 for IL-6 vs. IL-8; r = 0.81, p < 0.005 for IL-6 vs. G-CSF; and r = 0.84, p < 0.005 for IL-8 vs. G-CSF). Postoperative IL-6 levels and intraoperative blood loss correlated significantly (r = 0.64, p < 0.05). CONCLUSIONS: These results suggest that major upper abdominal surgery stimulates the release of inflammatory cytokines presumably from the operation site. Further study is warranted to evaluate the modulation of inflammatory responses in the perioperative period.

Abdomen↗