Search PubMed⌕ Search

Biomedical subjects

T Yoshimura

Publications and source records attributed to T Yoshimura.

At least 631 records · Page 35Linked to original sources
PubMed1987

Cell-free acylation of rat brain myelin proteolipid protein and DM-20.

Incubation of rat brain myelin with [3H]palmitic acid in the presence of ATP, CoA and MgCl2 or [14C]-palmitoyl-CoA in a cell-free system resulted in the selective labelling of 'PLP' [proteolipid protein; Folch & Lees (1951) J. Biol. Chem. 191, 807-817] and 'DM-20' [Agrawal, Burton, Fishman, Mitchell & Prensky (1972) J. Neurochem. 19, 2083-2089] which, after polyacrylamide-gel electrophoresis in SDS, were revealed by fluorography. These results provide evidence of the association of fatty acid-CoA ligase and acyltransferase in isolated myelin. Palmitic acid is covalently bound to PLP and DM-20, because 70 and 92% of the radioactivity was removed from proteolipid proteins after treatment with hydroxylamine and methanolic NaOH respectively. Incubation of myelin with [3H]palmitic acid in the absence of ATP, CoA, MgCl2, or all three, decreased incorporation of fatty acid into PLP to 3, 55, 18 and 2% respectively. The cell-free system exhibits specificity with respect to the chain length of the fatty acids, since myristic acid is incorporated into PLP at a lower rate when compared with palmitic and oleic acids. The acylation of PLP is an enzymic reaction, since (1) maximum incorporation of [3H]palmitic acid into PLP occurred at physiological temperatures and decreased with an increase in the temperature; (2) acylation of PLP with [3H]palmitic acid and [14C]palmitoyl-CoA was severely inhibited by SDS (0.05%); and (3) the incorporation of fatty acid and palmitoyl-CoA into PLP was substantially decreased by the process of freezing-thawing and freeze-drying of myelin. We have provided evidence that all of the enzymes required for acylation of PLP and DM-20 are present in isolated rat brain myelin. Acylation of PLP in a cell-free system with fatty acids and palmitoyl-CoA suggests that a presynthesized pool of non-acylated PLP and DM-20 is available for acylation.

Acylation↗
PubMed1987

Neutrophil chemotactic factor produced by lipopolysaccharide (LPS)-stimulated human blood mononuclear leukocytes: partial characterization and separation from interleukin 1 (IL 1).

LPS stimulated human blood mononuclear leukocytes to produce a chemotactic factor for human neutrophils. The effect of LPS was dose-dependent; 10 micrograms/ml was optimal for production of chemotactic factor. Chemotactic activity was detected 3 hr after LPS stimulation, and reached its peak at 12 hr. No activity was detected in culture supernatants of unstimulated cells, provided LPS-free media were selected. Isoelectric point of the factor, determined by chromatofocusing, was approximately 8 to 8.5. Molecular weight was approximately 10 kilodaltons by Sephacryl S-200 gel filtration or by HPLC gel filtration on TSK-2000 and -3000 columns in succession. The gel filtration fractions were also assayed for IL 1 activity. The elution position of IL 1 activity corresponded to a m.w. of 18. There was no chemotactic activity in the IL 1 activity peak. Furthermore, highly purified natural Il 1 alpha and -beta and recombinant Il 1 alpha and -beta did not exhibit chemotactic activity for neutrophils in our assay. Among mononuclear leukocytes, the monocyte was the principal producer of neutrophil chemotactic factor. These results suggest that a chemotactic factor for neutrophils, different from IL 1, is produced by LPS-stimulated blood monocytes.

Chemotactic Factors↗
PubMed1987

Spectral properties of nitric oxide complex of cytochrome c' from Rhodopseudomonas capsulata B100.

The spectral properties for NO complexes of ferric and ferrous cytochrome c' from photosynthetic bacterium Rhodopseudomonas capsulata B100 are reported. The electronic absorption, MCD, and EPR spectra have been compared with those of the NO complexes of the other cytochromes c' and horse heart cytochrome c. The NO-ferrous cytochrome c' would be a mixture of NO complexes with six- and five-coordinate nitrosylheme, suggesting that the heme-iron to histidine bond in the ferrous cytochrome c' is more stable than that from chemoheterotrophic bacteria. The reaction product of ferric cytochrome c' with NO exhibited the spectra similar to NO-ferric derivatives of the other hemoproteins, which indicates the formation of NO-ferric cytochrome c'.

Animals↗
PubMed1987

Spectral properties of cytochrome c' from Rhodopseudomonas capsulata B100 and its CO complex.

The spectral properties of cytochrome c' from photosynthetic bacterium Rhodopseudomonas capsulata (= Rhodobacter capsulatus) B100 and its CO complex are reported. The electronic absorption, MCD, and EPR spectra have been compared with those of the other cytochromes c' and horse heart cytochrome c. EPR and electronic spectral results for the ferric cytochrome c' suggest that the ground state of heme-iron(III) at neutral pH consists of a quantum mechanical admixture of an intermediate-spin and a high-spin state and that at pH 11.0 is in a high-spin state. In the MCD spectrum of the CO-ferrous cytochrome c', the MCD intensity in the Soret band region was much higher than that of CO complexes of hemoproteins with a protoheme. The differences in a stereochemistry of the sixth-coordination position is discussed.

Carbon Monoxide↗
PubMed1987

Different and synergistic actions of human tumor necrosis factor and interferon-gamma in damage of liposome membranes.

The effects of human recombinant tumor necrosis factor (TNF) and interferon-gamma (IFN-gamma) in damage of liposome membranes were examined to elucidate the molecular mechanism of their antiproliferative actions on tumor cells. The extent of membrane damage was assayed by measuring the rate of release of the fluorescent dye calcein encapsulated in the liposomes at different pH values in the presence of TNF and/or IFN-gamma. At pH values below about 5, TNF bound to phospholipid liposomes composed of mixtures of phosphatidyl-serine and phosphatidylcholine in molar ratios of 2:1 and 1:2 and caused rapid release of calcein. In contrast, IFN-gamma induced very slow leakage of dye although it bound almost completely to the membranes, suggesting that it causes much less membrane damage than TNF. Small amounts of these two antitumor factors bound to phosphatidylcholine liposomes in the pH range of 4-7, inducing relatively slow leakage of calcein. In the presence of both TNF and IFN-gamma at pH 5, the maximal leakage rate was twice the sum of the rates with the two proteins individually, and the rate depended on the TNF/IFN-gamma ratio, indicating synergistic effects of TNF and IFN-gamma in induction of membrane damage. These different and synergistic actions on liposome membranes may account for the different antitumor properties of the two antitumor cytokines and their synergism.

Antineoplastic Agents↗
PubMed1987

Establishment of a common acute lymphoblastic leukemia cell line (LC4-1) and effects of phorbol myristate acetate (PMA) on the surface antigen expression of the cell line.

A common acute lymphoblastic leukemia (ALL) cell line, designated LC4-1, was established from peripheral blood mononuclear cells of a patient with acute non-T-cell ALL. LC4-1 cells were characteristically positive for Ia, B4, and common ALL antigens (CALLA), but negative for B2, Tac, T3, T4, T8, T11, and M1 antigens and E-rosette formation. Approximately 30% of LC4-1 cells expressed detectable amounts of B1 antigens. LC4-1 cells expressed neither Epstein-Barr-virus-associated nuclear antigen (EBNA), cytoplasmic immunoglobulins (cIg) nor surface immunoglobulins (sIg). Gene rearrangements had already occurred in LC4-1 in the D-J region of immunoglobulin heavy chain genes, but not in T-cell receptor (beta-chain) genes, suggesting that LC4-1 is a progenitor cell line of B-cell lineage earlier than pre-B-cells. The expression of cell surface antigens of LC4-1 was changed by treatment with 4-phorbol 12-myristate 13-acetate (PMA) (0.1 ng/ml) for 2 days. Before treatment with PMA, about 98% of LC4-1 cells were positive for B4, CALLA, and Ia. However, following treatment they lost CALLA expression without any change in expression of Ia and B4. There was no change in B1-positive population. The change in surface antigens on LC4-1 cells seems to be due to differentiation induced in the cells by PMA. These results support the hypothesis that CALLA is a differentiation antigen and suggest one possible differentiation pathway for pre-B-cells.

Antibodies, Monoclonal↗
PubMed1987

In vitro acylation of myelin PLP and DM-20 in the quaking mouse brain.

Both proteolipid proteins (PLP) and DM-20 were found to be present by the immunoblot technique in myelin isolated from quaking mouse brain; however, the relative concentration of these proteins in myelin from quaking brain was substantially reduced when compared to the control. Brain slices from littermate control and quaking mice were incubated with [3H]palmitic acid to determine the incorporation of fatty acid into myelin proteolipid proteins. Fluorography of gels containing myelin proteins from control and quaking mice brain revealed that both PLP and DM-20 were acylated. The incorporation of [3H]palmitic acid into quaking myelin PLP and DM-20 was reduced by 75% and 20% respectively of those in control brain. The significance of differential acylation of quaking myelin PLP and DM-20 is discussed with respect to availability of non-acylated pools of proteolipid proteins and the activities of acylating enzymes.

Acylation↗
PubMed1987

Kinetic analysis of the fluorescence reaction of histamine with orthophthalaldehyde.

Histamine reacts with orthophthalaldehyde (OPA) in an alkaline medium to form an unstable fluorescent adduct (Fbase). Acidification of the solution gives a stable adduct (Facid). In order to elucidate the mechanism of this fluorescence reaction, a kinetic study of this reaction was carried out. Although Fbase was believed to be the precursor of Facid, it was shown not to be the precursor of Facid owing to the effects of the reaction time in an alkaline medium and OPA concentration on the yields of Fbase and Facid. The kinetic analysis of the formation and degradation of Fbase revealed the pathway of the fluorescence reaction. On the basis of the results obtained in this study, the mechanism of the fluorescence reaction is proposed.

Aldehydes↗
PubMed1987

Gastric cancer diagnosed by biopsy of the uterine cervix.

Biopsy of the uterine cervix from a 46-year-old woman who suffered from epigastric pain and weight loss showed metastatic adenocarcinoma. The primary site of the tumor was the stomach. At laparotomy, disseminated adenocarcinoma on the peritoneum and Krukenberg's tumor in the right ovary were found. A palliative partial gastrectomy, resection of the right ovary, and postoperative chemotherapy were performed. The possible mechanism of metastasis of extragenital cancer to the uterus is discussed.

Adenocarcinoma↗
PubMed1987

Peritoneal tuberculosis with elevated serum CA 125 levels: a case report.

Laparotomy in a 62-year-old woman with elevated serum CA 125 antigen levels with the provisional diagnosis of ovarian carcinoma revealed peritoneal tuberculosis. After treatment with the bacteriocidal chemotherapeutic agents, the antigen level returned to the normal, and she has been well for 24 months postoperatively.

Antigens, Neoplasm↗
PubMed1987

The activities of cytokines are pleiotropic and interdependent.

Many cytokines with multiple effects on the growth and functions of a wide variety of target cells have been discovered. Consequently, cytokines may exhibit considerable overlap in their biological effects on lymphoid, myeloid and connective tissue target cells. Even biologically distinct cytokines may have similar effects by initiating the production of a cascade of identical cytokines or of one another. The benefits of this apparent redundancy and interdependence of these activities remain to be established. Our information concerning cytokines is still far from complete, as illustrated by the recent characterization of a novel chemotactic cytokine and identification of a family of related mediators.

Animals↗
PubMed1987

Purification of a human monocyte-derived neutrophil chemotactic factor that has peptide sequence similarity to other host defense cytokines.

Stimulated human monocytes release several proteins thought to play a role in inflammation, including interleukin 1, tumor necrosis factor, and plasminogen activator. We have purified another proinflammatory protein that is chemotactic for human neutrophils from conditioned medium of lipopolysaccharide-stimulated monocytes. After a series of steps that included anion-exchange chromatography, gel filtration, and HPLC on cation-exchange and reverse-phase columns, an apparently pure protein was obtained that migrated as a single 7-kDa band on NaDodSO4/polyacrylamide gels under reducing or nonreducing conditions. The amino acid composition of this monocyte-derived neutrophil chemotactic factor was different from that of interleukin 1 and tumor necrosis factor. N-terminal amino acid sequence of the first 42 residues was determined. This portion of the molecule has up to 56% sequence similarity with several proteins that may be involved in host responses to infection or tissue injury. It is identical to a portion of a sequence deduced from an mRNA induced by staphylococcal enterotoxin treatment of human leukocytes. At the optimal concentration of 10 nM, 50% of neutrophils added to chemotaxis assay wells migrated toward the pure attractant. Potency and efficacy are comparable to that of fMet-Leu-Phe, which is often used as a reference. In contrast to many attractants, the protein was not chemotactic for human monocytes.

Amino Acid Sequence↗
PubMed1987

Cause-specific mortality among Koreans, Chinese and Americans in Japan, 1973-1982.

Mortalities from selected causes from 1973 to 1982 among Koreans, Chinese, and Americans residing in Japan were compared with those of Japanese. In the Korean population, besides the well-documented excess in mortalities from liver cancer, lung cancer, liver cirrhosis and male tuberculosis, a rather prominent elevation was observed for mortalities from female tuberculosis and diabetes mellitus in both sexes. Distinctive features in the Chinese population were increased mortalities from liver cancer and female lung cancer and lowered mortality from stomach cancer, and these findings are consistent with the observations among Chinese in other areas. Mortalities from diabetes mellitus and liver cirrhosis was moderately increased in this population as well. Americans in Japan by and large showed a mortality pattern similar to that in the US although mortality from stroke among female Americans was rather elevated during the period 1973-1977. Epidemiological studies on Koreans and Chinese in Japan with reference to their lifestyle are strongly required.

Cause of Death↗
PubMed1987

Exposure of hydrophobic domains of clathrin in its membrane fusion-inducible pH region.

Clathrin induces fusion of phospholipid membranes containing phosphatidylserine when the pH of the medium is reduced below about 6. The hydrophobicity of clathrin in the membrane fusion-inducible pH region was examined. In the presence of clathrin, the fluorescence maximum of 1-anilinonaphthalene-8-sulfonate was shifted to shorter wavelengths and its fluorescence intensity increased at pH values below about 6. Steep increase of the fluorescence intensity of the fluorescent probe, N-(1-anilinonaphthyl-4)maleimide covatently bound to clathrin was observed in a similar pH region. The efficiency of resonance energy transfer from tryptophan to anilinonaphthyl residues in the clathrin molecule showed similar pH dependency. When Triton X-114 solutions containing clathrin were subjected to phase separation by raising the temperature from 0 degree to 30 degrees C at different pH values, clathrin remained in the aqueous phase above pH 6, whereas the protein was partitioned between the aqueous and detergent phases at pH 5-6, and was present only in the detergent phase below pH 5. The effective hydrophobicity of clathrin determined by the fluorescence method using cis-parinaric acid also increased at pH values below 6. Moreover, clathrin was aggregated by lowering the pH below 6. These results show that exposure of hydrophobic domains of clathrin through conformational change occurs in its membrane fusion-inducible pH region, suggesting the crucial role of protein hydrophobicity in the initiation of membrane fusion.

Clathrin↗
PubMed1987

Freeze fracture analysis of muscle plasma membrane in bupivacaine HCl-induced degeneration and regeneration.

We did freeze fracture analysis of bupivacaine HCl-induced muscle fiber damage. The muscle plasma membrane in rat extensor digitorum longus and soleus muscle was analyzed for the density of orthogonal arrays and caveolae at periods of five minutes to 60 days after application of the myotoxin. In degenerating muscle a decrease in the density of caveolae was observed. In regenerating extensor digitorum longus muscle, a decrease in the density of orthogonal arrays and an increase in the density of caveolae was present. The results show that freeze fracture alterations in fast twitch regenerating muscle are similar to those seen in the muscles of patients with Duchenne muscular dystrophy.

Animals↗
PubMed1987

Colony-stimulating factor and leukemia cell-growth factor produced by a murine endothelial cell line, MKM-O.

A murine cultured cell line (MKM-O) was established from a tumor of a BALB/C (nu/nu) mouse that had been subcutaneously inoculated with human hepatoma tissue fragments in the same location. The MKM-O cell line was proven to be of endothelial origin by morphological examinations and positive staining with fluorescein-labeled antibody against factor VIII antigen. MKM-O cells grown in vitro produced a colony-stimulating factor (CSF) and a leukemia cell-growth factor (LC-GF). CSF from MKM-O acted on both human and murine bone marrow-derived granulocytes and macrophage colony-forming units (CFU-GM). The activity of LC-GF on human leukemia cell lines (HL-60, HSB-2, CEM, DAUDI and K562) was demonstrated both in conditioned medium (CM) of MKM-O and of rat vascular endothelial cells. The CM of MKM-O also demonstrated a limited growth promoting activity against the mononuclear cells from human cord blood and improved their survival, suggesting that endothelial cells play an important role in the proliferation and differentiation of blood cells.

Animals↗
PubMed1987

Low burst promoting activity production by phytohemagglutinin-stimulated mononuclear cells of cord blood.

Burst-promoting activity (BPA) produced by phytohemagglutinin(PHA)-stimulated cord blood mononuclear cells (MNC) was examined using the two-stage cell culture assays. Burst-promoting activity was measured as the increase in the number of early erythroid progenitor cells in 2-day incubation of peripheral blood MNC with or without the conditioned medium of PHA-stimulated MNC (PHA-LCM). Burst-promoting activity in PHA-LCM of cord blood was significantly lower than that of adult blood (37 +/- 13 versus 105 +/- 19%, mean +/- SD, p less than 0.01). No elevation of inhibitors to the erythroid colony growth was noted in PHA-LCM of cord blood. In contrary, the response of cord blood MNC to PHA was similar to that of adult blood MNC, as determined by colony-stimulating activity production and cell proliferation. These results showed that burst-promoting activity production by PHA-stimulated MNC of cord blood was lower than that of adult blood.

Cells, Cultured↗