Biomedical subjects

K Tashiro

Publications and source records attributed to K Tashiro.

At least 19 recordsLinked to original sources

PubMed1997

Autosomal dominant spastic paraplegia linked to chromosome 2p: clinical and genetic studies of a large Japanese pedigree.

Autosomal dominant spastic paraplegia (ADSP) is a genetically heterogenous disorder. To date, 3 loci of ADSP have been identified on chromosome 2p, 14q, and 15q, but specific gene mutations remain unknown. To determine the genetic background of ADSP in the Japanese, we studied a large 3-generation pedigree, clinically and genetically. Of the 36 individuals clinically examined, 15 were affected. The main feature in the affected individuals was a slowly progressive spastic paraplegia, associated with upper limb hyperreflexia (58%), reduction of vibration sense (27%) and bladder disturbance (13%). Age at onset ranged from 13 to 50 years with a mean of 30.3 +/- 14.2 (SD). There were 6 parent-child pairs with anticipation and at least 3 others with 'anti-anticipation'. Linkage with 14q and 15q ADSP loci was excluded, and a highly significant lod score was obtained only in the case of the 2p locus (Zmax = 3.53 for D2S400/D2S352, at theta = 0.00). Our study is the first to confirm the existence of 2p-linked ADSP in the Japanese. There is a significant variety in age at onset and disease severity in these 2p-linked families, but the implication for underlying ADSP mutation is not clear.

Adolescent↗

PubMed1997

Somatodendritic localization of phosphorylated tau in neonatal and adult rat cerebral cortex.

We studied the distribution of phosphorylated tau (p-tau) in neonatal and adult rat cerebrum using monoclonal antibodies that recognize distinct tau epitopes in a phosphorylation-dependent manner. In neonatal cortex, p-tau was detected in the apical dendrites and somata of pyramidal neurons as well as in axons. In adults, p-tau was present predominantly in neuronal somata and dendrites and, to a lesser extent, in axons, whereas tau-1, that recognizes a dephosphorylated tau epitope, immunolabeled neuropil and axons, and not the neuronal somata and dendrites. These results suggest that tau phosphorylated at multiple sites is present in somatodendritic compartments of rat cortical neurons throughout life, and that phosphorylation may be one of the determinants for the compartmentalization of tau in the brain.

Animals↗

PubMed1997

Clonal HTLV-I-infected CD4+ T-lymphocytes and non-clonal non-HTLV-I-infected giant cells in incipient ATLL with Hodgkin-like histologic features.

Lymph nodes from the incipient or early neoplastic phase of adult T-cell leukemia/lymphoma (ATLL) histologically resemble Hodgkin's disease. Integrated proviral human T-lymphotrophic virus type I (HTLV-I) has been demonstrated in such lesions. We studied 18 patients with this disease, and about half of the cases developed typical ATLL within 2 or 3 years. In all cases, either mono- or oligoclonal cell populations with proviral HTLV-I DNA were detected by Southern blot analysis and/or inverse polymerase chain reaction (IPCR). In addition, either a mono- or oligoclonal rearrangement of T-cell receptor genes was demonstrated. Giant cells with Reed-Sternberg-like histological features revealed CD15 and CD30 positivity. The background infiltrating lymphocytes represented either no or only minimal nuclear abnormalities with a CD4+ T-cell phenotype. In less than half of all cases, Epstein-Barr virus (EBV) infected the giant cells. A mixed EBV-A and -B type was found in 3, and a multiple genotype of EBV lymphocyte-determined membrane antigen (LYDMA) was found in 6 cases. These results could have been due to the immunodeficient status of the patients. A single-cell PCR of the giant cell, B cell, CD4+ or CD8+ T cells could be performed after cell sorting in 4 cases. HTLV-I infection was frequently found in the CD4+ T cells, but in neither the giant cells nor the B cells. The CD4+ T cells exhibited clonality. The giant cells showed various PCR products of IgH, and also expressed recombination activating genes (RAG). In summary, the giant cells were reactive cells, which resembled the immature B-lineage cells, while HTLV-I infected the CD4+ T cells, which demonstrated clonality. Based on these above findings, we consider CD4+ cells to play an important role in ATLL tumorigenesis.

Adolescent↗

PubMed1997

Direct involvement of the ubiquitin-conjugating enzyme Ubc9/Hus5 in the degradation of IkappaBalpha.

The NF-kappaB/Rel proteins are sequestered in the cytoplasm in association with IkappaBalpha. In response to external signals, IkappaBalpha is phosphorylated, multi-ubiquitinated, and degraded by proteasomes, thereby releasing NF-kappaB/Rel proteins to migrate to the nucleus. We have cloned a mouse ubiquitin-conjugating enzyme (mE2), which associates with IkappaBalpha. mE2 is homologous to the yeast Ubc9/Hus5 ubiquitin-conjugating enzyme. A transdominant-negative mutant of mE2 had no effect on phosphorylation of IkappaBalpha, but delayed its degradation. Correspondingly, tumor necrosis factor-alpha-inducible NF-kappaB activity was diminished. We propose that mE2 is directly involved in the ubiquitin conjugation of IkappaBalpha, a pivotal step in its degradation pathway.

Amino Acid Sequence↗

PubMed1997

Calumenin, a Ca2+-binding protein retained in the endoplasmic reticulum with a novel carboxyl-terminal sequence, HDEF.

We have identified and characterized a cDNA encoding a novel Ca2+-binding protein named calumenin from mouse heart by the signal sequence trap method. The deduced amino acid sequence (315 residues) of calumenin contains an amino-terminal signal sequence and six Ca2+-binding (EF-hand) motifs and shows homology with reticulocalbin, Erc-55, and Cab45. These proteins seem to form a new subset of the EF-hand protein family expressed in the lumen of the endoplasmic reticulum (ER) and Golgi apparatus. Purified calumenin had Ca2+-binding ability. The carboxyl-terminal tetrapeptide His-Asp-Glu-Phe was shown to be responsible for retention of calumenin in ER by the retention assay, immunostaining with a confocal laser microscope, and the deglycosylation assay. This is the first report indicating that the Phe residue is included in the ER retention signal. Calumenin is expressed most strongly in heart of adult and 18.5-day embryos. The calumenin gene (Calu) was mapped at the proximal portion of mouse chromosome 7.

Amino Acid Sequence↗

PubMed1997

D-aspartic acid localization during postnatal development of rat adrenal gland.

Developmental changes in cellular localization of D-aspartic acid (D-Asp) were investigated in rat adrenal gland with polyclonal anti-D-Asp antibody. At 1 and 3 weeks of age, immunoreactivity (IR) toward this amino acid was intense in the cytoplasm of cells in the zona fasciculata (ZF) and zona reticularis (ZR) of the adrenal cortex but was less so in the zona glomerulosa (ZG). Conversely at 8 weeks of age, intense IR was observed in the ZG and less in the ZF and ZR. In the adrenal medulla, IR was evident in large clusters of cells which were identified as adrenaline-storing cells. The emergence of D-Asp in specific types of cells at distinct periods of development of rat adrenal gland suggests that this amino acid may have a physiological role in the maturation of the organ.

Adrenal Cortex↗

PubMed1997

Cloning of human chromosome 17-specific cDNAs using representational difference analysis and human-mouse hybrid cells.

We employed cDNA representational difference analysis (RDA) with human-mouse somatic hybrid cells containing human chromosome 17 and obtained several cDNA clones specific for this chromosome. A cDNA library from PHA-stimulated T cells was screened with unknown cDNA clones obtained by RDA as probes. Subsequently, 1 complete gene and 1 partial cDNA clone were obtained. Our successful result implies that this subtractive amplification technique with hybrid cells will be a useful aid in positional cloning in large-spanning regions.

Amino Acid Sequence↗

PubMed1997

Cloning of Xenopus Dr1 (TBP-binding repressor) and its expression in oocytes and early embryos.

With a final goal to study how TBP-binding repressor Dr1 regulates transcription in Xenopus early embryos, we cloned its cDNA from Xenopus liver cDNA library. The cDNA was 1,986 bp long, with the open reading frame coding for 175 amino acids, whose sequence was highly homologous to its human counterpart. Xenopus Dr1 mRNA was expressed from the earliest stage of oogenesis, inherited as maternal mRNA at a high level, but its level became low at and after the neurula stage where RNA synthetic activity is strongly activated. Dr1 mRNA occurred in larger amounts in the animal half than in the vegetal half in 8-cell stage embryos, and in neurula and tailbud stage embryos its distribution was slightly larger in the anterior part than in the posterior part. These data show that Dr1 mRNA is expressed in a temporally and spatially regulated manner, and its occurrence at higher levels in earlier stage embryos may be responsible for their low transcriptional activity.

Amino Acid Sequence↗

PubMed1997

Immunohistochemical localization of D-aspartate in the rat pineal gland.

Specific polyclonal antibody was raised against D-aspartate (D-Asp) which had been conjugated to glutaraldehyde and was purified by affinity chromatography. Immunohistochemical staining of rat pineal gland with the antibody demonstrated the presence of D-Asp in the cytoplasm of pinealocytes, the predominant cell type in this gland. D-Asp immunoreactivity was more evident in the distal region than in the proximal region of the gland. Pinealocytes in the distal region are presumably involved in the synthesis and secretion of the pineal hormone, melatonin, and the results of staining may indicate some yet unknown role of D-Asp in the regulation of melatonin secretion.

Animals↗

PubMed1997

Molecular cloning of a novel mouse aspartic protease-like protein that is expressed abundantly in the kidney.

By use of the signal sequence trap method, we isolated a cDNA encoding a novel aspartic protease-like protein from the mouse kidney, and termed it 'kidney-derived aspartic protease-like protein (KAP).' The protein, a 419-amino-acid polypeptide with a 16-amino-acid signal sequence, had 47% identity with mouse cathepsin D, and its overall structure was closely related to known aspartic proteases. Northern blot analysis revealed that KAP mRNA is expressed at the highest level in the kidney, at a moderate level in the lung, and at low levels in the spleen and adipose tissue. In situ hybridization analysis demonstrated that the mRNA is expressed abundantly in the proximal straight tubule and slightly, but significantly, in the proximal convoluted tubule in the kidney. This intra-renal distribution differs distinctly from those of previously reported proteases such as cathepsins B, D, and H.

Amino Acid Sequence↗

PubMed1997

Clonal integration and expression of human T-cell lymphotropic virus type I in carriers detected by polymerase chain reaction and inverse PCR.

Adult T-cell leukemia (ATL) is a neoplasm of mature helper (CD4) T lymphocytes, and human T-cell lymphotropic virus type-I (HTLV-I) has been suggested to be the causative virus of ATL. HTLV-I integrates its proviruses into random sites in host chromosomal DNA. Clonal integration has been observed in patients with ATL, including smoldering, chronic, and acute states. However, random and/or polyclonal integration has only been reported in a few asymptomatic HTLV-I carriers. To clarify the clonality of HTLV-I-infected cells in carriers, we used an inverse polymerase chain reaction (IPCR), which is more sensitive than Southern blot analysis. We used the peripheral blood momonuclear cells (PBMC) from 16 asymptomatic carriers and the separated CD4-positive cells. No cases showed either a monoclonal or polyclonal integration of the HTLV-I provirus by Southern blot. But, using IPCR, 7 of 16 cases showed either mono- or oligoclonal integration. In addition, the populations of clonal provirus in the total PBMC were frequently different from those in the CD4-positive cells. Three cases showed expression of HTLV-I tax/rex mRNA in the total PBMC, but no such expression was found in CD4-positive cells. In this study, an unexpected frequency of clonal HTLV-I provirus DNA was observed in HTLV-I carriers. These findings indicate that the clonal but nonmalignant proliferation of HTLV-I-infected cells already occurs even in HTLV-I carriers, and therefore that some other step is necessary to induce malignant proliferation.

Adolescent↗

PubMed1997

Terminal deoxynucleotidyl transferase staining of malignant lymphomas in paraffin sections: a useful method for the diagnosis of lymphoblastic lymphoma.

Terminal deoxynucleotidyl transferase (TdT) is a DNA polymerase located in the cell nucleus which catalyses the polymerization of deoxynucleotides at the 3'hydroxyl ends of oligo- or polydeoxynucleotide initiators without a template. TdT is known as a useful marker for the diagnosis of acute lymphoblastic leukaemia/lymphoma, but its detection usually requires fresh tissue specimens or cell suspensions, using either an enzyme analysis or immuno-fluorescence or -peroxidase staining. Until the recent development of the use of microwave-treated paraffin sections for immunoperoxidase staining, detection of TdT in paraffin sections required rather complicated processes. This new simple technique was applied to paraffin sections from the tumour tissue specimens of 16 patients with lymphoblastic lymphoma and of seven patients with non-endemic Burkitt's lymphoma, which is sometimes difficult to differentiate from lymphoblastic lymphoma because of their similar clinicopathological characteristics. In addition, as a control, ten cases each were examined of adult T-cell leukaemia/lymphoma (ATLL) and angioimmunoblastic lymphoma (AILD), which are both peripheral T-cell lymphomas. The tumour cells from 15 of the 16 (94 per cent) patients with lymphoblastic lymphoma were found to be TdT-positive. The specificity of the anti-TdT antibody used was confirmed by immunoblot and the specific 60 kD band was detected only in a specimen of lymphoblastic lymphoma. These results show that the immunostaining of TdT on paraffin-embedded sections is a useful method for differentiating lymphoblastic lymphoma from other lymphomas. This method is applicable to a routine diagnostic service.

Adolescent↗

PubMed1997

Assignment of the possible HTLV receptor gene to chromosome 17q21-q23.

We have determined the HTLV (Human T-cell leukemia virus) receptor localization more precisely on the human chromosome 17. Based on the fact that HTLV infection induces syncytium formation of infected cells as a result of interaction between the viral envelope and viral receptor, we performed the sensitive biological assay using recombinant vaccinia expression system. Our results from the induced syncytium pattern of the somatic hybrid cell lines with different deletions indicated that the HTLV receptor gene may reside from q21 to q23 on the long arm of the human chromosome 17.

Animals↗

PubMed1997

Dominantly inherited leukodystrophy showing cerebellar deficits and spastic paraparesis: a new entity?

We studied a dominant hereditary disorder showing progressive spastic paraparesis. The symptoms began in early childhood, with cerebellar deficits and mild mental deterioration, and the subsequent appearance of limb spasticity resulted in severe disability in the 3rd-4th decades of life. None of the patients were associated with any somatic abnormalities. Brain MRI showed diffuse white-matter involvement in all affected patients, but not in unaffected siblings. Although dominant, recessive, or X-linked leukodystrophies cause similar clinical features, our family did not show any known biochemical or gene deficits characteristic of these disorders. The clinical, radiological, and biochemical findings of this family are reported and suggest a possible novel genetic disorder.

Adult↗

PubMed1997

Anti-nuclear antibodies and the optic-spinal form of multiple sclerosis.

We found anti-nuclear antibodies (ANA) (1:20 or higher) in sera from 11 of 16 patients with a diagnosis of the optic-spinal form of multiple sclerosis (OpS-MS) and 13 of 59 patients with other forms of MS (other MS), both rates being significant (P = 0.0004). Six of the OpS-MS patients had a high level of ANA (1:80 or higher), while levels were high in only three of the other MS patients, showing a significant difference (P = 0.0022). Titres of ANA were significantly higher in OpS-MS patients than in other MS patients (P < 0.0001). There was no relationship between the presence of ANA and age in OpS-MS patients, while patients with were older than those without high ANA levels among other MS patients. ANA-positive rate and titres were significantly higher in OpS-MS patients than in sex- and age-matched other MS patients. These results support the concept that OpS-MS constitutes a distinct subgroup among patients with a clinical diagnosis of MS and may indicate that systemic dysregulation of the inflammatory or immune response is more common in OpS-MS patients; the possible pathogenetic relevance of ANA-associated vasculopathy to some patients with a clinical diagnosis of OpS-MS should be considered.

Adult↗

PubMed1997

Identification of cell types producing RANTES, MIP-1 alpha and MIP-1 beta in rat experimental autoimmune encephalomyelitis by in situ hybridization.

The chemokines RANTES, macrophage inflammatory protein (MIP)-1 alpha and MIP-1 beta are members of the beta-family of chemokines and potent chemoattractants for lymphocytes and monocytes. To investigate the factors which regulate lymphocyte traffic in experimental autoimmune encephalomyelitis (EAE), we studied, by in situ hybridization analysis, the kinetics of mRNA expression and the potent cellular sources of RANTES, MIP-1 alpha and MIP-1 beta in the central nervous system (CNS) during the course of EAE. RANTES-positive cells appeared in the subarachnoid space and infiltrated the subpial region at around day 10, increased to a peak at days 12-13 and then decreased following the resolution of the acute phase of EAE, though elevated RANTES message expressions still remained on chronic subclinical stage. Most of RANTES positive cells were identified as T-lymphocytes located mainly around blood vessels, by combined studies of in situ hybridization and immunohistochemistry. The remainder of the RANTES-positive cells were astrocytes and macrophages/microglia. MIP-1 alpha and MIP-1 beta mRNA-positive cells appeared around day 10, increased further on days 12-13 and then gradually decreased. Most of the MIP-1 alpha- and MIP-1 beta-positive mononuclear cells were located around blood vessels. The kinetics of RANTES, MIP-1 alpha and MIP-1 beta expression paralleled those of the recruitment of infiltrating inflammatory cells and disease severity. Our observations support the possibility that chemokine production by T-cells, macrophages and astrocytes lead to the infiltration of inflammatory cells into the CNS parenchyma during the acute phase of EAE.

Animals↗

PubMed1997

Two closely-related left-right asymmetrically expressed genes, lefty-1 and lefty-2: their distinct expression domains, chromosomal linkage and direct neuralizing activity in Xenopus embryos.

BACKGROUND: Vertebrates have numerous lateral asymmetries in the position of their organs, but the molecular basis for the determination of left-right (L-R) asymmetries remains largely unknown. TGFbeta-related genes such as lefty and nodal are L-R asymmetrically expressed in developing mouse embryos, and may be involved in L-R determination. RESULTS: We have identified two highly conserved genes, lefty-1 and lefty-2, in the mouse genome. These two genes are tightly linked on mouse chromosome 1. lefty-1 and lefty-2 are both expressed in a L-R asymmetric fashion in mouse embryos. However, the major expression domains of the two genes are different: lefty-1 expression is predominantly confied to the left side of ventral neural tube, whereas lefty-2 is strongly expressed in the lateral plate mesoderm on the left side. In embryos homozygous for the iv and inv mutation, which cause situs inversus, the expression sites of both genes are affected, either reversed or bilaterally, indicating that lefty-1 and lefty-2 are downstream of iv and inv. Although Lefty-1 and Lefty-2 prepro-proteins are not readily processed in cultured cells, BMP2-Lefty chimeric proteins can be processed to a secreted form. We have examined the activities of Lefty-1 and Lefty-2 in Xenopus embryos. In animal cap explants, Lefty-1 and Lefty-2 induce neural cells in the absence of mesoderm induction. The direct neuralizing activities of Lefty-1 and Lefty-2 thus seem remarkably similar to those of BMP antagonists such as noggin and chordin, suggesting that the action of Lefty-1 and Lefty-2 may be to locally antagonize BMP (bone morphogenic protein)-mediated signals in tissues positioned on the left side of the mouse embryos. CONCLUSION: There are two lefty genes in mice (lefty-1 and lefty-2), both of which are expressed in a L-R asymmetric fashion and are downstream of iv and inv. Lefty-1 and Lefty-2 possess direct neuralizing activity in Xenopus embryos, resembling the activities of BMP antagonists.

Amino Acid Sequence↗

PubMed1997

Effects of surfactant proteins SP-B and SP-C on dynamic and static mechanics of immature lungs.

To investigate the effects of surfactant proteins B (SP-B) and C (SP-C) on lung mechanics, we compared tidal and static lung volumes of immature rabbits anesthetized with pentobarbital sodium and given reconstituted test surfactants (RTS). With a series of RTS having various SP-B concentrations (0-0.7%) but a fixed SP-C concentration (1.4%), both the tidal volume with 25-cmH2O insufflation pressure and the static volume deflated to 5-cmH2O airway pressure increased, significantly correlating with the SP-B concentration: the former increased from 6.5 to 26.0 ml/kg (mean), and the latter increased from 6.4 to 31.8 ml/kg. With another series of RTS having a fixed SP-B concentration (0.7%) but various SP-C concentrations (0-1.4%), the tidal volume increased from 5.1 to 24.8 ml/kg, significantly correlating with the SP-C concentration, whereas the static volume increased from 3.4 to 32.0 ml/kg, the ceiling value, in the presence of a minimal concentration of SP-C (0. 18%). In conclusion, certain doses of SP-B and SP-C were indispensable for optimizing dynamic lung mechanics; the static mechanics, however, required significantly less SP-C.

Animals↗