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Biomedical subjects

Y Ohshima

Publications and source records attributed to Y Ohshima.

At least 217 records · Page 12Linked to original sources
PubMed1979

Assumed initiation site of fibroin gene transcription.

To map the initiation site of fibroin gene transcription on cloned genomic fibroin DNA (pFb29), we looked for precursors of fibroin mRNA, first by applying the hybridization mapping method to the RNA from the posterior silk gland of Bombyx mori. The 6.2-kilobase (kb) DNA fragment used for the assay, from 5.7 kb upstream to 0.5 kb downstream from the cap site, was end-labeled at the Xho I site (position +514) within the intervening sequence of the fibroin gene. By analyzing the labeled DNA protected by the RNA from nuclease S1 treatment, we have shown that the intervening sequence is transcribed together with the surrounding gene sequences in the posterior silk gland (producer) but not in the middle silk gland (nonproducer). Large transcripts that could include entire intervening (1 kb) and fibroin mRNA (16 kb) sequences were found. The 5' end of such transcripts was located around or near the cap locus. Synthesis and analysis of the DNA complementary to the transcripts primed within the intervening sequence region also confirmed that the 5' end of the transcripts is near the cap locus. These results strengthen the possibility that the cap site is the transcription initiation site of fibroin gene.

Animals↗
PubMed1979

Primitive neuroectodermal tumor (neuroepithelioma) of spinal nerve root -- Report of an adult case and establishment of a cell line.

A case of primitive neuroectodermal tumor arising in the cervical nerve root of a 28-year-old man is presented. Histologically, the tumor was characterised by proliferation of primitive neuroectodermal cells and formation of numerous Homer-Wright type rosettes. A cell line (Nagai line) was established from the tumor. Electron microscopic examination of Nagai cells revealed numerous microrosette formation with microvilli-like cytoplasmic processes projecting into the central lumina. Neurosecretory granules appeared in the cytoplasmic processes when Nagai cells were treated with dibutyryl cyclic AMP. Primitive satellite cells which completely surrounded other tumor cells with their tongue-like slender cytoplasmic processes were also found. Histogenesis of this unique tumor was discussed comparing with the neuroblastoma of sympathetic nervous system, medulloblastoma of the central nervous system, and with the tumors induced by Adenovirus type 12 in animals. It was concluded that the tumor was neuroepithelioma derived from a primitive stem cell of neural crest origin which possesses the bipotency to differentiate toward either neuroblastic or neurilemmal line.

Adult↗
PubMed1977

Cloning of the silk fibroin gene and its flanking sequences.

Thirteen Escherichia coli clones containing the whole or a part of the fibroin gene (16 kilobases long) have been isolated. The starting material was DNA extracted from the posterior silk glands of Bombyx mori. Most clones were obtained from sheared DNA fragments linked by poly(dA)-poly(dT) joints to the plasmid pMB9. One of them includes the 5' end of the fibroin gene with a flanking sequence of 12 kilobases, and another includes the 3' end of the gene with a flanking sequence of about 1 kilobase. One clone was obtained by ligation, to pMB9, of a fragment generated by endodeoxy-ribonuclease EcoRI. This clone has a 21-kilobase insertion that probably includes the entire fibroin gene with flanking sequences at both ends. The cleavage sites for endodeoxyribonucleases EcoRI, HindIII, and BamHI have been established for the cloned sequences.

Base Sequence↗
PubMed1977

An electron microscope study of the intestinal absorption of medium chain and long chain triglycerides in the rat.

The ultrastructural changes in the intestinal absorptive cells of the rat during the absorption of triglycerides, Particularly medium chain triglyceride (MCT), were studied by electron microscopy. In the absorptive cell of rats fed with MCT, the agranular endoplasmic reticulum in tubular form was remarkably proliferated throughout the cytoplasm as compared with that of fasting rats. The granular endoplasmic reticulum was mostly transformed into the same tubulo-vesicular form as the agranular endoplasmic reticulum. Chylomicra, which were consistently observed in the endoplasmic reticulum of the intestinal absorptive cell of rats fed with long chain triglyceride (LCT), did not appear in that of MCT-fed rats, although small lipid particles were noticed within it. The Golgi lamellae decreased in number and length. During the absorption of MCT, the central lacteal contained some lipid particles which were smaller in size than the chylomicron which appeared in the LCT-fed rats. These evidences might suggest that the majority of MCT administered was transported through the absorptive cell without reesterification in the endoplasmic reticulum into the portal vein system, and only a minor part of the MCT given was transported via the central lacteal after reesterification.

Animals↗
PubMedDate not supplied

Induction of eosinophilic granules, nonspecific esterase activity and CD14 expression in the human eosinophilic leukemia cell line, EOL-1.

We examined the expression of eosinophilic granules, esterase activity and CD14 in a human eosinophilic cell line, EoL-1. Unstimulated EoL-1 cells were weakly positive for nonspecific esterase, but negative for surface CD14, and contained a few eosinophilic granule-positive cells. A combination of G-CSF and TNF-alpha increased the eosinophilic granule-containing cells, but failed to increase esterase activity or CD14 expression. IFN-gamma alone or in combination with TNF-alpha enhanced nonspecific esterase activity but failed to induce CD14 expression or increase eosinophilic granule-containing cells. dbcAMP increased eosinophilic granule-containing cells, nonspecific esterase activity and CD14 expression. Specific esterase activity was not detected in any circumstances. EoL-1 cells fractionated by density gradients or CD14 expression showed nonspecific esterase activity and CD14 expression in both the eosinophilic granule-positive and negative cell populations. Forskolin and butyrate had a synergistic effect on CD14 induction and protein kinase A was suggested to play a role in dbcAMP-induced CD14 expression. A protein kinase C activator, phorbol 12-myristate 13-acetate, did not increase eosinophilic granules, nonspecific esterase activity or CD14 expression in EoL-1 cells. The results show that EoL-1 cells can express nonspecific esterase and CD14, but the expression is not necessarily restricted to cells which have differentiated into the monocyte/macrophage lineage.

Antigens, CD↗
PubMedDate not supplied

Maturation of human neonatal CD4+ and CD8+ T lymphocytes into Th1/Th2 effectors.

The increased susceptibility of neonates to infections has been ascribed to the immaturity of their immune system. More particularly, T cell-dependent responses were shown to be biased towards a Th2 phenotype. Our studies on the in vitro maturation of umbilical cord blood T cells suggest that the Th2 bias of neonatal response cannot be simply ascribed to intrinsic properties of neonatal T cells. Phenotypically, neonatal CD4+ T cells are more immature than their adult CD45RO-/RA+ naive counterparts and they contain a subset (10-20%) of CD45RO-/RA+ CD31- cells which is very low in adults and displays some unique functional features. The activation and maturation of neonatal CD4+ T cells is particularly dependent upon the strength of CD28-mediated cosignal which dictates not only the cytokine profile released upon primary activation but also the response to IL-12. Activation of adult as well as neonatal CD4+ T cells in the context of low CD28 costimulation yields to the production of low levels of only one cytokine, i.e. IL-2. In contrast, strong CD28 costimulation supports the production of high levels of type 1 (IL-2, IFN gamma and TNF beta) and low levels of type 2 (IL-4 and IL-13) cytokines by neonatal T cells. The low levels of naive T cell-derived IL-4 are sufficient to support their development into high IL-4/IL-5 producers by an autocrine pathway. The ability of IL-12 to prime neonatal CD4+ T cells for increased production of IL-4 (in addition to IFN gamma) is observed only when CD28 cosignal is minimal. Under optimal activation conditions (i.e. with anti-CD3/B7.1 or allogenic dendritic cells) the response and the maturation of neonatal and adult naive T cells are similar. Thus the Th2 bias of neonatal immune response cannot be simply ascribed to obvious intrinsic T cell defect but rather to particular conditions of Ag presentation at priming. Unlike CD4+ T cells, neonatal CD8+ T cells strictly require exogenous IL-4 to develop into IL-4/IL-5 producers. Most importantly, anti-CD3/B7-activated neonatal CD8 T cells coexpress CD4 as well as CCR5 and CXCR4 and are susceptible to HIV-1 infection in vitro.

Adult↗
PubMedDate not supplied

Comparison of cell wall teichoic acid fractions isolated from three different encapsulated strains of Staphylococcus epidermidis.

Teichoic acid preparations extracted from the cell wall of three serologically different encapsulated strains of Staphylococcus epidermidis, ATCC-31432 (capsular type I), SE-360 (capsular type II) and SE-10 (capsular type III) were purified by DEAE-cellulose and Sephadex G-50 column chromatography. The preparations showed immunological heterogeneity by an agar diffusion test. The chemical properties of the cell wall teichoic acid preparations of capsular types I and III were regarded as N-acetyl-glucosaminyl glycerol-phosphate polymers containing N-acetylglucosamine and phosphate at molar ratios of 0.22-1.0 and 0.33-1.0, respectively. The preparation of capsular type II was assumed to be an alpha-glucosyl glycerol-phosphate polymer containing glucose and phosphate at a molar ratio of 0.49-1.0, and it reacted strongly with concanavalin A. Moreover, alanine, glycine, serine and lysine were shown, among these preparations, to be a common amino acid composition. These results indicate that cell wall teichoic acids obtained from these strains were biochemically and immunologically different from each other.

Cell Wall↗
PubMedDate not supplied

The let-23 gene necessary for Caenorhabditis elegans vulval induction encodes a tyrosine kinase of the EGF receptor subfamily.

The let-23 gene is required for induction of the Caenorhabditis elegans vulva. It is shown that let-23 encodes a putative tyrosine kinase of the epidermal growth factor receptor subfamily. Thus, let-23 might encode the receptor for the inductive signal required for vulval development. Because let-23 acts upstream of let-60 ras in the vulval determination pathway, the identification of the let-23 product provides support for a link in vivo between tyrosine kinase growth factor receptors and ras proteins in a pathway of cell-type determination.

Amino Acid Sequence↗
PubMedDate not supplied

Systemic inflammatory response syndrome and acute renal failure associated with Hemophilus influenzae septic meningitis.

Sepsis is often associated with a downward spiral through a spectrum of systemic inflammatory response syndrome (SIRS) culminating in organ failure and death. Here we present a 3-year-old girl with Hemophilus influenzae septic meningitis who developed SIRS and acute renal failure. In the initial stage, the patient showed uremia, cytopenia, disseminated intravascular coagulation, elevation of tissue enzyme and ferritin values, hemophagocytosis and overproduction of nitric oxide. The serum cytokine profile revealed increased levels of soluble interleukin (IL)-2 receptor, IL-6, IL-10 and tumor necrosis factor alpha. The patient responded positively to early and intensive interventions including antibiotics, repeated exchange transfusions, dexamethasone and high-dose gamma-globulin. The above laboratory abnormalities almost normalized with clinical improvement. We consider that SIRS was probably responsible for the sequence of events resulting in renal failure in this case, and suggest that renal failure should be included among the serious complications of SIRS associated with Hemophilus influenzae septic meningitis.

Acute Kidney Injury↗
PubMedDate not supplied

OX40-Mediated cosignal enhances the maturation of naive human CD4+ T cells into high IL-4-producing effectors.

Our previous studies have indicated that naive human CD4+ T cells of neonatal or adult origin may be the initial source of IL-4 which is required for their development into Th2 effectors. In addition to minute amounts of IL-4, anti-CD3/B7.1-activated naive cells also release readily detectable levels of IL-13 and IFN-gamma. The production of IL-4 and IL-13 by naive T cells is differentially regulated by TGF-beta and IL-12. Shortly after activation, naive T cells express surface OX40, a TNF-R family member whose ligand (OX40L) is constitutively expressed on a subset of dendritic cells. Engagement of OX40 on activated naive T cells increases their expression of IL-4 and IL-13, suppresses that of IFN-gamma and promotes their development into Th2-like effectors.

Adult↗