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Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 793 records · Page 44Linked to original sources
PubMed1994

Subcellular localization and characterization of interleukin-1 alpha produced by rat bladder cancer cells.

A rat bladder cancer cell line BC31ad, previously reported to constitutively release tumor necrosis factor alpha (TNF alpha), was found to produce an interleukin (IL)-1-like factor inducing proliferation of murine thymocytes in a standard costimulation assay (LAF activity). IL-1-like factor was partially purified by DEAE-Sephacel, Sephacryl S-200 and MonoQ-FPLC chromatographies from the serum-free conditioned medium of a BC31 adderived clone, C19, to the specific activity of 3.2 x 10(6) U/mg and characterized as a protein of molecular weight 17 kDa with isoelectric point 5.2. LAF activity of IL-1-like factor was specifically neutralized with anti-rat IL-1 alpha but not with anti-rat IL-1 beta. These findings show that the IL-1-like factor is rat IL-1 alpha, although the precise molecular relationship with monocyte IL-1 alpha is unclear. Furthermore, IL-1 alpha was shown to be primarily located in the cytosol and plasma membrane without spontaneous release. A kinetics study indicated that it was leaked into the medium late in culture resulting from cell destruction, in contrast to TNF alpha which was released as the cell number was increased. We discussed the possible role of IL-1 alpha as an autocrine or paracrine growth regulator.

Animals↗
PubMed1994

Precocious cessation of intestinal macromolecular transport and digestive enzymes development by prostaglandin E2 in suckling rats.

The effect of repeated oral administration of prostaglandin analogue (dmPGE2) on intestinal macromolecular transport and digestive enzymes development were investigated in the suckling rats. By the administration of dmPGE2 for 7 days, precocious induction of maltase activity, depression of amylase activity and enhancement of trypsin activity in the pancreas occurred. Absorption of bovine IgG was dose dependently depressed by dmPGE2 treatments. The intestinal cessation was also observed in the adrenalectomized pups, but was not influenced by difluoromethyl ornithine administration. These results suggest that oral administration of PGE2 induces precocious maturation of the small intestine and exocrine pancreas and that the intestinal cessation is not directly related to ornithine decarboxylase activity in the suckling rats.

Adrenalectomy↗
PubMed1994

Orally administered spermine induces precocious intestinal maturation of macromolecular transport and disaccharidase development in suckling rats.

The effect of orally administered spermine on intestinal cessation in bovine IgG transport and digestive enzymes in the small intestine was examined in the suckling rats. By the repeated oral administration of spermine (0.1 or 0.25 mumol/g bwt) for 5 days, the ratio of protein to DNA was significantly increased. Maltase and lactase activities changed dose dependently in the spermine treated pups. Absorption of bovine IgG transport in the intestine was dose dependently depressed by spermine treatments. Morphological inspection of treated pups showed a decline in the number of epithelial cells that absorb bovine IgG and in their vesicle sizes from basal to upper regions of the villi. The ratio of mitosis in the crypt of treated pups significantly increased in the small intestine and cecum. These results suggest that exogenously administered spermine induces precocious maturation of the macromolecular transmission and disaccharidase activity in the small intestine of the suckling rats.

Animals↗
PubMed1994

The Schwann cell precursor and its fate: a study of cell death and differentiation during gliogenesis in rat embryonic nerves.

We have characterized a cell, the Schwann cell precursor, that represents a distinct intermediate differentiation stage in the process by which Schwann cells are generated from neural crest cells. The Schwann cell precursor shows radical differences from Schwann cells which include death regulation, antigenic phenotype, pattern of cell-cell interaction, migratory behavior, and morphology. In the nerves of the rat hind limb, Schwann cells are irreversibly generated from these during a brief period, essentially embryonic days 15-17. We also provide evidence that the survival of Schwann cell precursors is regulated by neurons and identify basic fibroblast growth factor as a potential key regulator of apoptosis in Schwann cell precursors and of precursor to Schwann cell conversion. These findings have implications for our understanding of gliogenesis in the peripheral nervous system.

Animals↗
PubMed1994

Anatomical and histological re-examination of Appendices colli in the goat.

Appendices colli (App. colli) were investigated by anatomical and histological methods in the goat. App. colli were composed of elastic cartilage located at central and the skin covering the cartilage, which included arterioles along the cartilage and nerve bundles. Three types of muscles connected to App. colli; superficial muscle bundles, a branch of the omohyoideus muscle, and a muscle arising from the pharyngeal raphe (appendico-pharyngeal muscle). The latter two muscles were connected to the root of the App. colli where the muscle fibers transformed into the perichondrium of the elastic cartilage. The appendico-pharyngeal muscle was innervated by branches from the glossopharyngeal nerve which were composed of myelinated nerve fibers. The subcutaneous area of the App. colli was supplied by cutaneous rami of the vagus and the second cervical nerves. The innervation and the musculature confirmed that the cartilage of the App. colli were derived from third and fourth branchial arches.

Animals↗
PubMed1994

Natriuretic peptide-potentiating actions of neutral endopeptidase inhibition in rats with experimental heart failure.

We developed a rat model of heart failure induced by myocardial infarction (MI) which preserves responsiveness to exogenously administered natriuretic peptide, and investigated the potentiating action of neutral endopeptidase (NEP) inhibition on the renal response to endogenous natriuretic peptide in MI rats, comparing with that in the established cardiac-failing model with arterio-venous fistula (AVF). The endogenous plasma concentration of alpha-rat atrial natriuretic peptide (alpha-rANP) in the MI rat was 6.4-fold higher than that in the normal rat, and intravenous infusion of phosphoramidon (165 nmol/min/kg), an NEP inhibitor, induced larger increases in circulating alpha-rANP levels and natriuresis in MI rats than in normal controls. The maximal natriuretic effect of phosphoramidon (165 nmol/min/kg) was equal to that of exogenously administered alpha-rANP (100 pmol/min/kg) in MI rats, whereas plasma alpha-rANP concentration under NEP inhibition was much lower than that after administration of alpha-rANP. The endogenous alpha-rANP levels in AVF rats were as high as those in MI rats. However, the natriuretic effect of phosphoramidon was less in AVF rats than in MI rats, which was consistent with the decreased natriuretic activity observed with administration of exogenous to alpha-rANP in the AVF rat. These results indicate that the natriuretic effect of NEP inhibition is dependent on elevated endogenous alpha-rANP levels in cardiac-failing rats, but cannot be accounted for simply in terms of the increase in circulating alpha-rANP levels. Endogenous natriuretic peptide-mediated natriuresis under NEP inhibition also appears to correlate with the responsiveness to the exogenously administered peptide.

Animals↗
PubMed1994

Simulation for the analysis of distorted pharmacodynamic data.

A simulation study was conducted to compare the performance of alternative approaches for analyzing the distorted pharmacodynamic data. The pharmacodynamic data were assumed to be obtained from the natriurertic peptide-type drug, where the diuretic effect arises from the hyperbolic (Emax) dose-response model and is biased by the dose-dependent hypotensive effect. The nonlinear mixed effect model (NONMEM) method enabled assessment of the effects of hemodynamics on the diuretic effects and also quantification of intrinsic diuretic activities, but the standard two-stage (STS) and naive pooled data (NPD) methods did not give accurate estimates. Both the STS and the NONMEM methods performed well for unbiased data arising from a one-compartment model with saturable (Michaelis-Menten) elimination, whereas the NPD method resulted in inaccurate estimates. The findings suggest that nonlinearity and/or bias problems result in poor estimation by NPD and STS analyses and that the NONMEM method is useful for analyzing such nonlinear and distorted pharmacodynamic data.

Antihypertensive Agents↗
PubMed1994

Clearance mechanisms of atrial and brain natriuretic peptides in rats.

To assess clearance mechanisms of atrial and brain natriuretic peptides in the circulation, we examined the effects of a neutral endopeptidase (NEP) inhibitor and a clearance receptor ligand on plasma concentrations of the peptides in normal rats. Plasma concentrations of endogenous alpha-rat atrial natriuretic peptide (alpha-rANP) were not significantly elevated by intravenous infusion of a NEP inhibitor, phosphoramidon, but were elevated threefold by intravenous infusion of a clearance receptor ligand, des(Gln18-Gly22)-rANP(4-23)-NH2 [C-ANF(4-23)]. On the other hand, the clearance of alpha-rANP given intravenously at the pharmacological dose, 600 pmol/min/kg for 2 min, was decreased to one-third by the administration of phosphoramidon, although the administration of C-ANF(4-23) did not significantly decrease the clearance. The clearance of rat brain natriuretic peptide (rBNP) given at 600 pmol/min/kg for 2 min was approximately 38% lower than that of alpha-rANP. The effect of phosphoramidon on the clearance of rBNP was not significant and was similar to that of C-ANF(4-23). These results suggest that clearance receptor is involved in the clearance of the physiological levels of alpha-rANP and that NEP plays a major role in the clearance of a pharmacological dose of alpha-rANP, at which clearance receptors are thought to be saturated, and also indicate a pharmacokinetic difference between alpha-rANP and rBNP.

Amino Acid Sequence↗
PubMed1994

Correlative regulation of nerve growth factor level and choline acetyltransferase activity by thyroxine in particular regions of infant rat brain.

Effects of thyroxine (T4) on nerve growth factor (NGF) level and choline acetyltransferase (ChAT) activity of rat brains were investigated. Repetitive intraperitoneal administration of T4 caused increases in both NGF level and ChAT activity in the frontal cortex, septum, hippocampus, and striatum and decreases in the cerebellum in 2-day-old rats. Only ChAT activity was elevated in the olfactory bulb, and the NGF level remained unchanged there. No changes were observed in the midbrain and pons/medulla. Furthermore, T4 was effective on the postnatal rats only up to day 11. These results suggest that T4 plays a role in the developmental regulation of NGF level and ChAT activity in rat brain in a region- and/or stage-specific manner. That (1) changes in NGF level and ChAT activity occurred in regions nearly identical to those that contained NGF-responding neurons, and (2) the change in NGF level in the hippocampus and frontal cortex was followed by the change of ChAT activity after a single injection of T4 suggest that the effects of T4 on cholinergic differentiation are, at least in part, mediated via NGF, which itself is quantitatively regulated by T4.

Aging↗
PubMed1994

Autoimmune antibody in a patient with idiopathic thrombocytopenic purpura reacted to the platelet low molecular weight glycoproteins and activated platelets.

The authors characterized antiplatelet membrane antibodies in the sera of patients with idiopathic thrombocytopenic purpura (ITP) and cirrhosis of the liver. Antibodies were detected in five of the 22 patients with chronic ITP and in none of the eight patients with cirrhosis of the liver. The authors report a patient with chronic ITP in complete remission. Antibody to platelet glycoproteins (GP), with molecular weights of 55 and 49 kDa, was detected in the serum. The patient's immunoglobulin G (IgG) alone could cause the aggregation of platelet-rich plasma. Anti-GPIIb/IIIa antibody (LJ-CP8) inhibited the aggregation of platelet-rich plasma induced by the patient's IgG in a dose-dependent manner. The F(ab')2 of the patient's IgG had a synergetic effect on the aggregation of PRP induced by adenosine 5-diphosphate. This demonstrates that in ITP, the binding of IgG via its fragment of antigen binding site portion may activate platelets.

Aged↗
PubMed1994

Entry of CD4-CD8- immature thymocytes into the CD4/CD8 developmental pathway is controlled by tyrosine kinase signals that can be provided through TCR components.

Entry of thymus-migrated precursor cells into the CD4/CD8 developmental pathway was analyzed by using the short-term organ cultures of day 14 fetal mouse thymus lobes. Organ cultures of CD4-CD8- day 14 fetal thymocytes for 1-2 days resulted in the generation of CD4-CD8+ cells, which were mostly immediate precursor cells for CD4+CD8+ thymocytes. This differentiation of CD4-CD8- thymocytes into CD4-CD8+ cells was strongly enhanced by anti-CD3 antibodies. The anti-CD3- induced generation of CD4-CD8+ cells was even found in the immunodeficient scid fetal thymus cultures, and the cell surface CD3 expression on the scid fetal thymocytes could be directly visualized, indicating that functional CD3 could be expressed on CD4-CD8- immature thymocytes without being associated with rearranged TCR components. The anti-CD3-induced generation of CD4-CD8+ cells from scid and normal fetal thymus cultures was inhibited by tyrosine kinase inhibitors Herbimycin A and Tyrphostin. The generation of CD4-CD8+ cells in unstimulated normal fetal thymus cultures was also markedly inhibited by the tyrosine kinase inhibitors but not by Cyclosporin A, suggesting that tyrosine kinase-dependent but calcineurin-independent signals were essential for the differentiation of CD4-CD8- thymocytes. Interestingly, the generation of CD4-CD8+ cells from the normal fetal thymus cultures was modestly but consistently enhanced by anti-TCR beta antibody, suggesting that functional TCR beta in addition to CD3 was expressed on normal CD4-CD8- immature thymocytes. On the other hand, anti-TCR delta antibody did not affect this differentiation in the normal fetal thymus cultures and the generation of CD4-CD8+ cells from the fetal thymus cultures of TCR delta-deficient mice was still enhanced by anti-TCR beta or anti-CD3 antibodies, indicating that either TCR delta chains or TCR delta+ cells were not involved in the control of the differentiation into CD4-CD8+ cells. These results indicate that the entry of CD4-CD8- immature thymocytes into the CD4/CD8 developmental pathway is controlled by tyrosine kinase signals and that these signals can be provided through the engagement of TCR-CD3 complexes with or without TCR beta chains expressed on the CD4-CD8- immature thymocytes.

Animals↗
PubMed1994

Binding of serum albumin on tumor cells and characterization of the albumin binding protein.

The binding of bovine (BSA) and human serum albumin (HSA) to the surface of human and mouse tumor cells in vitro was examined by flow cytometry using monoclonal antibodies against these albumins. Both isologous and heterologous types of albumin bound firmly on several lines of human and mouse tumor cells. The cell-bound albumin was removable by protease (actinase) treatment or by culture in albumin-free medium for more than 2 days, but not by simple washing. The amount of albumin capable of binding to the tumor cell surface differed among the 9 tumor cell lines tested. As determined with radioiodinated BSA, about 2.6 x 10(6) BSA molecules/cell could bind to MDA-MB-453 human mammary cancer cells, which exhibit high binding capacity as to BSA. A unique peptide having a molecular weight of 18 kDa was detected on gel electrophoresis in extracts of tumor cells or normal aortic endothelial cells which had been treated with radioiodinated, photocross-linker-labeled BSA or HSA, followed by UV-irradiation. This peptide was also immuno-precipitated with an anti-BSA or anti-HSA monoclonal antibody. With both methods, the yield of the peptide was decreased by previous addition of an excess amount of unlabeled BSA or HSA. These findings indicated that the 18-kDa peptide expressed on both normal aortic endothelial cells and tumor cells is a principal serum albumin-binding protein, and that this protein binds both BSA and HSA.

Animals↗
PubMed1994

Pre-Kupffer like CD4/CD8 double positive mononuclear cells present in rat liver.

Nonparenchymal cells isolated from Fischer rat liver were separated into subpopulations by passage through a nylon wool column and/or culturing in a plastic plate. Besides typical Kupffer cells, we detected a unique population of cells (called PKu cells) which were plastic adherent but did not spread on a short term culture, were nonadherent on nylon wool, and were nonphagocytic, as opposed to Kupffer cells. Both Kupffer cells and PKu cells expressed CD4 (recognized with W3/25 mAb), CD8 (OX-8), a NK cell antigen (3.2.3), and a monocyte antigen (OX-41), as assessed by flow cytofluorometry. However, the proportion of cells bearing high densities of CD8 and 3.2.3 antigens was much larger for PKu cells than for Kupffer cells. Reverse transcriptase-PCR analysis of CD8 mRNA revealed that PKu cells expressed the CD8 alpha chain but not the beta chain. When PKu cells were treated with phorbol 12-myristate 13-acetate (PMA), they exhibited spreading and phagocytic activities, and showed a similar morphology to Kupffer cells in the spread form. Moreover, PMA treatment decreased the high density of CD8 antigen on PKu cells. These findings indicated that PKu cells present in normal rat liver are precursors of Kupffer cells.

Animals↗
PubMed1994

Epitope mapping of bovine serum albumin using monoclonal antibodies coupled with a photoreactive crosslinker.

Antigenic determinants (epitopes) on bovine serum albumin (BSA) to anti-BSA monoclonal antibodies (mAbs) were assessed by means of photoaffinity labeling. Anti-BSA mAbs, AB3 and AB6, were modified with an 125I-labeled photoreactive crosslinker, sulfosuccinimidyl 2-(p-azidosalicylamido)ethyl-1,3'-dithiopropionate (SASD) and then bound with BSA. The complex yielded was irradiated with UV light to facilitate covalent binding of the modified mAb with BSA. Reduction of the product with 2-mercaptoethanol revealed that radioactivity of 125I-SASD was specifically introduced into BSA, probably near the mAb combining site(s). The radiolabeled or native BSA was digested with V8 protease and the peptides produced were assessed for their amino acid sequence, the radiolabeled amino acids contained, and their reactivity to mAb. The results indicated that AB3 mAb recognized an epitope in the region of Ala-537 to Asp-554 on a linear part of the BSA molecule, whereas AB6 mAb probably recognized an epitope of the assembled form present in a peptide of Asp-299 to Glu-338.

Amino Acid Sequence↗
PubMed1994

16S ribosomal DNA sequences of anaerobic cocci and proposal of Ruminococcus hansenii comb. nov. and Ruminococcus productus comb. nov.

The 16S ribosomal DNA sequences of representative members of the family Peptococcaceae were determined. The members of the family examined were divided into the following four phylogenetic groups: Peptococcus niger ATCC 27731T (T = type strain), the Sarcina-Peptostreptococcus anaerobius group, the ruminococcus-coprococcus group, and the peptostreptococcus group. Peptococcus niger, the type species of the family, was not related to other members of the family. Peptostreptococcus anaerobius ATCC 27337T, the type strain of the type species of the genus Peptostreptococcus, was closely related to Clostridium sordellii NCIB 10717T (level of sequence similarity, 85%). Sarcina ventriculi GIFU 7886, a spore-forming anaerobic gram-positive coccus, clustered with Clostridium perfringens ATCC 13124T at a similarity value of 91%. Members of the Sarcina-Peptostreptococcus anaerobius group clustered with clostridia at similarity values ranging from 85 to 91%. The type strains of Peptostreptococcus prevotii, Peptostreptococcus asaccharolyticus, Peptostreptococcus micros, and Peptostreptococcus magnus clustered at levels of sequence homology of 84 to 93%. This cluster was not included in the Peptococcus niger group or the Peptostreptococcus anaerobius group. Thus, these members of the genus Peptostreptococcus should be separated from the other members of the genus and also from members of the family Peptococcaceae. The sequence of Peptostreptococcus productus ATCC 27340T was different from the sequences of Peptostreptococcus anaerobius and Peptococcus niger. The sequence of Streptococcus hansenii ATCC 27752T, a strictly anaerobic strain, was different from the sequences of other streptococci; this strain clustered with Peptostreptococcus productus, coprococci, and ruminococci. Several phenotypic characteristics of Streptococcus hansenii ATCC 27752T were similar to characteristics of ruminococci.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaerobiosis↗
PubMed1994

The p10 gene of natural isolates of Bombyx mori nuclear polyhedrosis virus encodes a truncated protein with an M(r) of 7700.

Sequence analysis of the p10 genes of three Bombyx mori nuclear polyhedrosis virus (BmNPV) isolates collected in Taiwan (Ta) and Japan (T3 and D1) showed that all possessed a deletion of an adenine residue, 210 bp downstream from the first base of the initiation codon when compared to the p10 gene of Autographa californica (multinucleocapsid) NPV (AcMNPV). This deletion caused a downstream termination codon to come inframe with the coding sequence of p10, so that the p10 gene of BmNPV encoded a protein of 70 amino acid residues with an M(r) of 7700. This is considerably shorter than the 10,000 M(r) protein encoded by the closely related AcMNPV.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of a novel hair follicle-specific gene, Hacl-1.

We have isolated a hair-follicle-specific gene, termed hacl-1, from a cDNA library of ICR mouse skin. Hacl-1 is expressed specifically in skin, and its mRNA level is correlated with the active state of hair follicles in developmental and regenerative processes of hair. Its mRNA is approximately 1 kilobase pairs (kb). Its cDNA was completely co-linear with the genomic clone, indicating that the hacl-1 gene is composed of one exon. The hacl-1 gene has an open reading frame of 579 base pairs (bp). The deduced amino acid sequence showed six direct repeats of a decapeptide on the C-terminal side. The repetitive unit contains a CQP motif, which is present in repetitive peptide sequences of some hair- and epidermal-cell-specific proteins. In situ hybridization with a 3' untranslated region of the hacl-1 cDNA as a probe showed that hacl-1 was expressed specifically in the keratogenous zone of the cortical cells of the hair shaft. No other components of hair follicles or epidermis showed a positive signal. Thus, hacl-1 is a novel, hair-follicle-specific gene.

Amino Acid Sequence↗