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Biomedical subjects

K Tashiro

Publications and source records attributed to K Tashiro.

At least 379 records · Page 21Linked to original sources
PubMed1991

Apolipoproteins in rat cerebrospinal fluid: a comparison with plasma lipoprotein metabolism and effect of aging.

Cerebrospinal fluid (CSF) apo E concentrations, determined by a sensitive sandwich ELISA, were 411.3 +/- 76.0 and 454.3 +/- 51.8 micrograms/dl (mean +/- S.D.) for young rats (8-12 weeks old, n = 7) and old rats (36-40 weeks old, n = 10), respectively. Age-related increase, which was conspicuous in serum apo E (21.2 +/- 2.4 vs 60.9 +/- 14.1 mg/dl for young and old rats, respectively), was not observed in CSF apo E. CSF apo A-I concentrations, determined by ELISA, were extremely low in the both groups (less than 10 micrograms/dl). Neither CSF apo A-I nor CSF apo E correlated to any of the plasma lipoprotein components, indicating the presence of largely independent lipoprotein metabolism in the rat central nervous system. Apo E is present in CSF in the form of apo E-rich HDL1 with particle sizes similar to those of plasma E-rich HDL1.

Aging↗
PubMed1991

Expression of the RAG-2 gene in murine central nervous system tumor cell lines.

Two tightly linked recombination activating genes, RAG-1 and RAG-2, are involved in VDJ recombination of the immune system. Although these genes were originally thought to be expressed exclusively in precursor B and T cells, RAG-1 transcripts were recently found in the murine central nervous system (CNS) [Chun et al., Cell 6, 189, (1991)]. We found that the RAG-2 gene was expressed in CNS tumor cell lines, melanoma (B-16) and skin fibroblast (A9). RAG-1 expression was not found in any non-lymphoid cell lines examined including CNS tumor cell lines. Another VDJ recombination-related gene RBP-Jk was expressed in all tumor cell lines examined. It remains to be seen whether expression of RAG-1 and RAG-2 in CNS is abortive or functionally important.

Animals↗
PubMed1991

Cell membrane signaling as target in cancer therapy. II: Inhibitory effect of N,N,N-trimethylsphingosine on metastatic potential of murine B16 melanoma cell line through blocking of tumor cell-dependent platelet aggregation.

Two phenotypic parameters, aberrant expression of protein kinase C and tumor cell-induced platelet aggregation (PA), have been correlated with abnormal growth behavior and metastatic potential of tumor cells. We recently observed that N,N,N-trimethylsphingosine (TMS) and N,N-dimethylsphingosine (DMS), but not sphingosine (SPN), had an inhibitory effect (via blocking of transmembrane signaling) on the growth of various human tumor cell lines in vitro as well as in vivo in nu/nu mice (K. Endo et al., Cancer Res., 51: 1613-1618, 1991). We therefore investigated the effects of TMS, DMS, and SPN on (a) PA induced by ADP and thrombin; (b) PA induced by melanoma cell line B16/BL6; and (c) experimental lung colonization as well as spontaneous lung metastasis of BL6 cells in syngeneic C57BL/6 mice. In experiments on agonist-induced PA, TMS inhibited PA and ATP secretion 5-fold more strongly than DMS or SPN. This effect may be based on the inhibition of Mr 47,000 platelet protein phosphorylation and/or inhibition of phosphatidylinositol turnover as a transmembrane signaling pathway in platelets. Tumor cell (BL6 melanoma)-induced PA and ATP secretion were also strongly inhibited by TMS, but not by DMS or SPN. Unlike ADP- or thrombin-induced PA, BL6 cell-induced PA was not inhibited by Calphostin-C (a potent protein kinase C inhibitor) or cilostazol (a potent inhibitor of PA based on inhibition of cyclic AMP phosphodiesterase). Since many previous studies suggested that the ability of tumor cells to induce PA is related to the degree of malignancy (e.g., metastatic potential) of tumor cells, we studied the effect of TMS on lung metastatic potential. Three independent sets of experiments, as described below, all showed clear inhibition of lung metastasis by administration of TMS: (a) i.v. coinjection of BL6 melanoma cells and TMS; (b) i.v. injection of TMS and, 1 h later, BL6 cells; (c) spontaneous metastasis to lung from s.c. BL6 tumor (TMS administered after establishment of tumor, followed by resection of tumor). In comparison to tumor growth inhibition produced by TMS or DMS, inhibition of melanoma metastasis by TMS is obvious at lower doses.

Adenosine Triphosphate↗
PubMed1991

Functional expression of furin demonstrating its intracellular localization and endoprotease activity for processing of proalbumin and complement pro-C3.

We have cloned a rat cDNA encoding furin which is structurally related to yeast Kex2 protease. Products of 88 and 94 kDa were obtained by in vitro transcription/translation of the cDNA in the absence and presence of microsomes. When the cDNA was transfected into COS-1 cells, furin was expressed as a major glycosylated form of 94 kDa, accompanied by a minor proteolytic form of 86 kDa, and found to be localized in the Golgi complex. Proalbumin and complement pro-C3 are intracellularly processed into their mature forms by cleavage at the dibasic residues Arg-Arg, a common cleavage signal found in many pro-type precursors. In cells transfected with the cDNA of C3 or albumin alone, only about half of each proform expressed was processed by an endogenous activity of the cells. When furin was coexpressed, the proforms of both C3 and albumin were completely processed into their mature forms. In addition, co-expression of rat alpha 1-protease inhibitor mutant (Met352----Arg) resulted in inhibition of the endogenous and exogenous processing activities, as observed for the naturally occurring mutant Pittsburgh which has been identified as a specific inhibitor for the processing enzyme. Taken together, these results indicate that furin is an endoprotease localized to the Golgi complex and capable of processing proalbumin and pro-C3 into the mature forms.

Amino Acid Sequence↗
PubMed1991

Deduced primary structure of a Xenopus proteasome subunit XC3 and expression of its mRNA during early development.

Proteasome is a non-lysosomal proteinase complex ubiquitously distributed in eukaryotic cells. We isolated here the cDNA clone for one of the proteasome subunits (XC3) from Xenopus ovary cDNA libraries using rat RC3 cDNA as a prove. The cDNA is 885 bp long and encodes 234 amino acids. The deduced amino acid sequence is highly homologous (95.3%) to those of rat RC3 and human HC3 subunits. The mRNA for XC3 is one of the maternal mRNAs and detected at all the embryonic stages investigated, but its level changes in a characteristic way especially at the gastrula stage. We suggest that the highly conserved XC3 subunit plays an essential role in proteasome function and also that during Xenopus embryogenesis mRNA for XC3 subunit is replaced from maternal to newly-synthesized one probably around the gastrula stage.

Amino Acid Sequence↗
PubMed1991

Different stromal cell lines support lineage-selective differentiation of the multipotential bone marrow stem cell clone LyD9.

An interleukin 3-dependent multipotential stem cell clone, LyD9, has been shown to generate mature B lymphocytes, macrophages, and neutrophils by coculture with primary bone marrow stromal cells. We report here that coculture with the cloned stromal cell lines PA6 and ST2 can support differentiation of LyD9 cells predominantly into granulocyte/macrophage colony-stimulating factor (GM-CSF)- and granulocyte (G)-CSF-responsive cells, respectively. However, these stromal cell lines were unable to support lymphopoiesis of LyD9 cells. The GM-CSF-dependent line, L-GM, which was derived from LyD9 cells cocultured with PA6 stromal cells, could differentiate into macrophages and granulocytes in the presence of GM-CSF. The L-GM line can further differentiate predominantly into neutrophils by coculture with ST2 stromal cells. The G-CSF-dependent line, L-G, which was derived from LyD9 cells cocultured with ST2 stromal cells, differentiated into neutrophils in response to G-CSF. Although the stromal cell-supported differentiation of LyD9 cells required the direct contact between LyD9 and stromal cells, a small fraction of LyD9 cells that were pretreated with 5-azacytidine could differentiate into neutrophils and macrophages without direct contact with stromal cells. These results indicate that different stromal cell lines support lineage-selective differentiation of the LyD9 stem cell and that 5-azacytidine treatment can bypass the requirement of direct contact with stromal cells, albeit with a lower frequency.

Animals↗
PubMed1991

Premature expression of the macrophage colony-stimulating factor receptor on a multipotential stem cell line does not alter differentiation lineages controlled by stromal cells used for coculture.

We are interested to know whether expression of a lineage-specific growth factor receptor is deterministic to lineage commitment during hematopoiesis. For this purpose, we introduced the human c-fms gene into the multipotential stem cell clone LyD9 and two myeloid progenitor clones, L-GM3 and L-G3, cells that differentiate in response to granulocyte/macrophage colony-stimulating factor (GM-CSF) and granulocyte (G)-CSF, respectively. Although LyD9 cells have differentiation potential to become macrophages, c-fms transfectants of LyD9 and L-GM3 cells did not differentiate in response to human macrophage (M)-CSF. However, c-fms transfectants of L-G3 cells differentiated to neutrophils in response to human M-CSF. These results indicate that the M-CSF receptor requires a specific signal transduction pathway to exert its differentiational and proliferative effects. Furthermore, the M-CSF receptor can convey a granulocyte-type differentiation signal possibly by cooperating with the G-CSF receptor signal transduction pathway. The c-fms-transfected LyD9 cells as well as the original LyD9 cells differentiated predominantly into GM-CSF- and G-CSF-responsive cells by coculturing with PA6 and ST2 stromal cells, respectively. The results indicate that differentiation lineage is not affected by premature expression of the M-CSF receptor. Instead, the stromal cell used for coculture apparently controls lineage-selective differentiation of the multi-potential stem cell line.

Animals↗
PubMed1991

Expression of mRNA for activin-binding protein (follistatin) during early embryonic development of Xenopus laevis.

Follistatin is a specific activin-binding protein and is supposed to control activin functions. During Xenopus embryonic development, activin is thought to act as a natural mesoderm-inducing factor. We isolated here the Xenopus follistatin cDNA from Xenopus ovary cDNA library and studied the expression of Xenopus follistatin gene during the course of early embryonic development. The Xenopus follistatin has an 84% homology at the level of deduced amino acid sequence with human and porcine follistatin. Its 3.5 kb mRNA is first expressed at the gastrula stage, when the expression of activin mRNA becomes first detectable, and increased thereafter. Another species of 2 kb mRNA become detectable from early neurula and also increased dramatically in tadpole. These results suggest that the follistatin acts also as a regulator of activin in inductive interactions during amphibian embryonic development.

Amino Acid Sequence↗
PubMed1991

The RGD containing site of the mouse laminin A chain is active for cell attachment, spreading, migration and neurite outgrowth.

The laminin A chain has been sequenced by cDNA cloning and was found to contain an RGD sequence. Synthetic peptides containing the RGD sequence and flanking amino acids were active in mediating cell adhesion, spreading, migration, and neurite outgrowth. Furthermore, endothelial cell attachment to a laminin substrate was inhibited by an RGD-containing synthetic peptide. Antisera against the integrin (fibronectin) receptor, and monoclonal antibody to the integrin, VLA-6, inhibited cell interaction with laminin, as well as with peptides containing an RGD sequence. These results suggest that the RGD containing site of laminin is active and interacts with the integrin family of receptors in certain cells.

Amino Acid Sequence↗
PubMed1991

Chronic multifocal demyelinating neuropathy associated with central nervous system demyelination.

We have carried out a long-term study of lesions found in a man who had a demyelinating disease of both central and peripheral nervous systems. During the 10 years of his clinical course, he suffered from optic neuritis, multifocal myelitis, and chronic multifocal demyelinating neuropathy, with persistent conduction block. Our study revealed that both central and peripheral nervous system demyelination occurred repeatedly and simultaneously.

Adult↗
PubMed1991

Germline transcripts of the immunoglobulin heavy-chain and T cell receptor genes in a murine hematopoietic stem cell line LyD9 and its derivative cell lines.

We compared germline transcript levels of immunoglobulin heavy chain and T cell receptor (TcR) genes in a murine hematopoietic stem cell line, LyD9, and its derivative cell lines. LyD9 cells can be induced to differentiate into at least three lineages, namely, B lymphocyte, macrophage, and granulocyte lineages. Although C mu transcripts were found in stem cells to B lymphocytes, other myeloid-committed cells also expressed significant amounts of C mu transcripts. Germline TcR transcripts did not show good correlation with differentiation potential and stages of hematopoietic cells. During this search we identified a novel germline transcript containing the JH-C microliter sequence in LyD9 and some of its derivative cells. Expression of mRNAs for immunoglobulin- and TcR-associated molecules (lambda 5, MB1 and CD3 delta) was widespread except for lambda 5 mRNA. Among three mRNAs encoding putative recombinase proteins, RAG-1 and RAG-2 mRNAs were not expressed in any cell lines tested, while RBP-2 mRNA was expressed ubiquitously.

Animals↗
PubMed1991

Demyelinating peripheral neuropathy in Devic disease.

This is a report of a 20-year-old man with typical features of Devic disease (neuromyelitis optica) associated with demyelinating peripheral neuropathy. A sural nerve biopsy showed markedly decreased myelinated fibers of a large diameter. Teased fiber preparations showed segmental remyelination in 50% of examined fibers, as well as a few demyelination. Demyelination of bilateral optic nerves, spinal cord, and peripheral nerves at the same time suggests a possibility of common pathogenetic mechanisms in both the central and peripheral nervous systems.

Adult↗
PubMed1991

Disseminated intravascular coagulation in a patient with progressive systemic sclerosis associated with necrotizing angiitis and generalized lymphadenopathy.

A 47-year-old woman with progressive systemic sclerosis developed disseminated intravascular coagulation in the course of her terminal illness. She also had complicating necrotizing angiitis and generalized lymphadenopathy. The likely relationship between disseminated intravascular coagulation and vasculitis is discussed.

Disseminated Intravascular Coagulation↗
PubMed1991

A multi-center, double-blind study on slow-release bromocriptine in the treatment of Parkinson's disease.

We report on the clinical efficacy of a slow-release formulation of bromocriptine studied in a multi-center, double-blind trial using standard bromocriptine as the control. We randomly allocated enrolled patients (N = 243) to either the slow-release or normal bromocriptine group. Sixty of them were de novo patients. The maintenance dose of slow-release bromocriptine was 14.2 +/- 0.7 mg/d and that of standard bromocriptine 13.5 +/- 0.7 mg/d (mean +/- SE). The slow-release formulation was taken twice and the standard three times a day. Forty-one percent of the patients treated with the slow-release bromocriptine and 32% of the patients treated with the standard bromocriptine showed moderate or marked improvement in the global improvement rating. There were no serious side effects, and the frequency of vomiting and epigastric discomfort was lower in the patients treated with the slow-release bromocriptine. Clinical efficacies for tremor, rigidity, akinesia, and gait disturbance were comparable between the two drugs tested. The slow-release bromocriptine seems to be a valuable drug for the treatment of Parkinson's disease with less severe side effects than regular bromocriptine.

Aged↗
PubMed1991

Two cases of neoplastic angioendotheliomatosis presenting with myelopathy.

We describe two patients with autopsy-proven neoplastic angioendotheliomatosis (NAE) presenting only as a transverse myelopathy for 10 to 12 months, followed by disseminated intracranial manifestations. Postmortem examination disclosed a vasculocentric distribution of neoplastic cells in various organs that stained positively with B-lymphocyte-specific monoclonal antibody. These cases were unusual because they manifested as an isolated myelopathy for many months.

Brain↗
PubMed1991

Survival of Yersinia enterocolitica in soil and water.

Yersinia enterocolitica O3, O4, O5A, O5B, O6, O6, 30, O9 and O13 and Yersinia intermedia were examined to clarify their survival in natural soil, river water and well water. The O3 strain disappeared most rapidly from soil at both temperature of 4 degrees C and 20 degrees C and from river water at 20 degrees C. Although the O5B and O9 strains disappeared before the O3 strain did from river water at 4 degrees C, the O9 strain survived as long as non-virulent strains did in soil at 4 degrees C. The O3, O5B and O9 strains survived longer at 4 degrees C than at 20 degrees C in soil and river water. Non-virulent strains of O4, O5A and O6 survived longer in well water than in soil and river water. Although the O3 and O5A strains disappeared from supernatant filtered with 100 microns and 5 microns pore size filters, they maintained their viable cell numbers in supernatant of soil filtered with 0.22 microns pore size filter and in the autoclaved supernatant.

Animals↗