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Biomedical subjects

K Takatsuki

Publications and source records attributed to K Takatsuki.

At least 307 records · Page 17Linked to original sources
PubMed1989

Possible involvement of protein kinase C in proliferation and differentiation of osteoblast-like cells.

In cloned osteoblast-like cells, MC3T3-E1, 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C activating phorbol ester, and 1-oleoyl-2-acetylglycerol (OAG), a specific activator for protein kinase C, stimulated DNA synthesis in a dose-dependent manner. Both TPA and OAG acted synergistically with insulin-like growth factor I to stimulate DNA synthesis. TPA as well as OAG suppressed the increase in alkaline phosphatase activity of MC3T3-E1 cells induced by parathyroid hormone. These results suggest that protein kinase C is involved in the process which directs osteoblast-like cells toward proliferation.

Alkaline Phosphatase↗
PubMed1989

An interesting syndrome of hemolytic anemia, degeneration of the liver and diabetes associated with a high red cell Mg-ATPase, detected by 31P NMR spectroscopy.

31P NMR was used to study the erythrocytes of three patients who exhibited a familial multisystem disease characterized by fatty liver, diabetes and nonspherocytic hemolytic anemia of unknown etiology. 31P NMR measurements disclosed an abnormally high level of intracellular inorganic phosphate (Pi) and an abnormally low level of ATP in the erythrocytes 6 h after blood withdrawal from proband (I-1). This finding suggested that ATP was markedly decreased in the red cells of this proband, as compared with those of normal subjects. Time-dependent changes of 31P NMR spectra of the erythrocytes from the two daughters (II-1, II-2) of the proband demonstrated clearly an enhanced decomposition of ATP with a concomitant increment of Pi. Several ATP-consuming enzymes in erythrocytes, such as those in the Embden-Meyerhof system, pentose phosphate pathway enzymes, Na+, K(+)-ATPase and Ca2+, Mg2(+)-ATPase, were within normal limits of activity, but Mg2(+)-ATPase was drastically above the normal limit. The Mg2(+)-ATPase activity was 3 times higher in the red cell membranes of these patients than in those from normal subjects.

Adult↗
PubMed1989

Amylase-producing multiple myeloma. Cytochemical, immunohistochemical and immunoelectron microscopic studies.

The first autopsy case of amylase-producing IgA-lambda-type multiple myeloma is described. Immunohistochemically, amylase and alpha and lambda chains of immunoglobulin were demonstrated in the cytoplasm of the myeloma cells. Secretion of amylase by cultured myeloma cells obtained from the patient's pleural effusion was clearly demonstrated by the starch film method. Immunoelectron microscopically, positive reaction products for amylase and the alpha chain of immunoglobulin were observed in the well developed endoplasmic reticulum. Since no secretory granules were observed, we postulated that the secretory process of amylase was not via the zymogen granules but via a mechanism similar to that for immunoglobulin.

Amylases↗
PubMed1989

A neutralizing epitope of human immunodeficiency virus type 1 has homologous amino acid sequences with the active site of inter-alpha-trypsin inhibitor.

A neutralizing epitope (epitope beta) of the HTLV-IIIB strain of HIV-1 was mapped to 24 amino acids of an external envelope glycoprotein (gp120) using a neutralizing monoclonal antibody (0.5 beta) and hetero-antisera against synthetic peptides encoding gp120. Proteins that have homologous sequences with epitope beta were sought from a databank of protein sequences to assess biological features of epitope beta. The results showed that epitope beta was found to have homologous sequences to inter-alpha-trypsin inhibitor (ITI). The homologous region of ITI included the active site of the protein. Synthesized peptides including epitope beta were good substrates for trypsin, because these peptides inhibited trypsin activities in a competitive manner (Ki = 24.5 microM). Human urinary trypsin inhibitor (UTI), a protein indistinguishable from ITI, as well as synthetic peptides including epitope beta inhibited syncytium formation caused by the LAV-1-infected CCRF-CEM and uninfected Molt-4 cells in a dose-dependent manner (0.1-1 mM). These findings suggest that epitope beta of HIV-1 could be substrate of protease upon HIV-1 infection and also suggest that protease inhibitory activity of epitope beta may play a role in the pathophysiology of HIV-1-infected individuals.

Alpha-Globulins↗
PubMed1989

Inhibition of human immunodeficiency virus infection of human lymphocytes by gangliosides.

As the first step in human immunodeficiency virus (HIV) infection, HIV binds to CD4 molecules on the surface of human T lymphocytes. Expression of CD4 by the cells is remarkably modulated by exogenously added gangliosides, which are normal components of the surface of animal cells. We report here that these physiological molecules also clearly inhibited HIV infection of lymphocytes in vitro in a dose-dependent manner through the selective modulation of CD4 from the cell surface. This raises the possibility of in vivo application of gangliosides as a new strategy for treating acquired immunodeficiency syndrome.

Antibodies, Monoclonal↗
PubMed1989

Phagocytic multiple myeloma with disseminated intravascular coagulation.

We describe an atypical case of IgG lambda multiple myeloma in a 28-year-old patient. He developed multiple cutaneous plasmacytomas, and the terminal event, leukemic conversion by phagocytic plasma cells and disseminated intravascular coagulation. Secretion of monoclonal immunoglobulin (IgG lambda) from myeloma cells was demonstrated by plaque-forming cell assay. Electron microscopy showed myeloma cells with well-developed rough endoplasmic reticulum and erythroid cells or platelets in intracytoplasmic vacuoles.

Adult↗
PubMed1989

Characterization of the fibrinolytic state by measuring stable cross-linked fibrin degradation products in disseminated intravascular coagulation associated with acute promyelocytic leukemia.

Plasma samples from patients with disseminated intravascular coagulation (DIC) associated with acute promyelocytic leukemia (APL) exhibited higher levels of the D-fragment of fibrin and fibrinogen degradation products [FDP(D)], with relatively lower levels of cross-linked fibrin degradation products (XDP), than samples of DIC with non-APL. The difference between FDP(D) and XDP levels increased only when alpha 2-plasmin inhibitor (alpha 2-PI) fell below 60% of the normal level in APL patients. These findings suggest that fibrinogenolysis occurs in APL patients when the alpha 2-PI level has decreased significantly.

Cross-Linking Reagents↗
PubMed1989

Synthesis of a novel cytokine and its gene (LD78) expressions in hematopoietic fresh tumor cells and cell lines.

The gene coding for the protein LD78 was isolated from stimulated human tonsillar lymphocytes by differential hybridization. The gene product consisted of 92 amino acids with characteristics of cytokines. LD78 gene transcripts were detected in eight of eight fresh samples of cells from patients with acute nonlymphocytic leukemia (ANLL) by Northern blot analysis. ANLL cells with monocytic features gave the strongest bands. RNA transcripts were found in two of three samples of cells from patients with adult T cell leukemia (ATL), eight of nine samples from patients with acute lymphocytic leukemia (ALL) of B cell lineage, and one of the three samples from patients with T cell ALL. KG-1, HL-60, HUT 102, MT-2, and MJ cell lines expressed the LD78 gene constitutively. The LD78 protein was detected in culture supernatants and cell lysates of HUT 102, MT-2, MJ, and fresh ATL cells by Western blot analysis. This protein was not found in culture supernatants or cell lysates of monocytic leukemia cells and HL-60 cells, although LD78 transcripts were found in those cells. The discrepancy between gene and protein expression might be explained by the stability of the mRNA. Thus, the protein may be involved in the neoplastic transformation of hematopoietic cells.

Biological Factors↗
PubMed1989

Neurohypophyseal function in postpartum hypopituitarism: impaired plasma vasopressin response to osmotic stimuli.

We studied neurohypophyseal function in 12 women with postpartum hypopituitarism (Sheehan's syndrome) by measuring plasma arginine vasopressin concentrations during 5% hypertonic saline infusions. All patients had a history of obstetric shock or massive bleeding, and were receiving cortisol and/or L-T4 replacement therapy. None had any symptoms of diabetes insipidus. The mean basal plasma vasopressin level in the patients [0.6 +/- 0.1 (+/- SE) pmol/L] was significantly lower (P less than 0.01) than that in normal adults (2.5 +/- 0.5 pmol/L; n = 12), whereas mean plasma osmolality values were similar in the two groups. During hypertonic saline infusion, the 10 hypopituitary patients had varying degrees of subnormal arginine vasopressin responses to the increase in plasma osmolality. Urine-concentrating ability after dehydration also was lower in the patients, although overt polyuria was absent at the time of this study. These results indicate that the osmoregulation of arginine vasopressin secretion is frequently impaired in postpartum hypopituitarism, suggesting neurohypophyseal damage.

Adult↗
PubMed1989

Association of HLA antigen and restriction fragment length polymorphism of T cell receptor beta-chain gene with Graves' disease and Hashimoto's thyroiditis.

HLA antigen phenotypes and BglII restriction fragment length polymorphism of T cell receptor beta-chain (TCR beta) gene were analyzed in 61 patients with Graves' disease and 50 patients with Hashimoto's thyroiditis. The antigen frequency of HLA-Bw46 in both Graves' disease (23.0%) and Hashimoto's thyroiditis (24.0%) was significantly higher than that in normal population (8.0%), with relative risks (RR) of 3.45 [corrected P (Pc) less than 0.009] and 3.66 (Pc less than 0.02), respectively. Significantly increased frequency of HLA-B51 antigen was also found in Hashimoto's thyroiditis (40.0% vs. 16.3% in controls; RR, 3.42; Pc less than 0.002). Hybridization of BglII-digested DNA with TCR beta probe revealed two alleles of 9.3 and 8.6 kilobases. The allele frequency of 8.6 kilobases in Graves' disease (79%) and Hashimoto's thyroiditis (76%) was significantly higher (P less than 0.01 and P less than 0.05, respectively) than that in controls (64%). The frequency of homozygous state 8.6/8.6 was significantly increased in both Graves' disease (62%) and Hashimoto's thyroiditis (60%) over that in controls (39%); the RR of 8.6/8.6 in Graves' disease and Hashimoto's thyroiditis were 2.55 (P less than 0.01) and 2.31 (P less than 0.05), respectively. These results indicate that in Japanese subjects at least two loci are involved in the susceptibility to Graves' disease and Hashimoto's thyroiditis, one related to HLA and another to TCR beta.

Alleles↗
PubMed1989

Mode of action of erythropoietin (Epo) in an Epo-dependent murine cell line. I. Involvement of adenosine 3',5'-cyclic monophosphate not as a second messenger but as a regulator of cell growth.

A subclone of the interleukin 3 (IL-3)-dependent murine cell line DA-1 was recently established, and its growth found to be dependent on erythropoietin (Epo) as well as on IL-3. This subclone, named DA-1ER, has been used to study the mechanisms of action of these two growth factors, though most especially of Epo. In the present study, the involvement of adenosine 3',5'-cyclic monophosphate (cAMP) in the growth of DA-1ER cells was analyzed. In initial experiments, cAMP levels in cells stimulated with either recombinant Epo or recombinant IL-3 were monitored. The results showed that no significant changes in cellular cAMP levels had occurred. The cAMP-enhancing agents, N6-2'-o-dibutyryl-adenosine 3',5'-cyclic monophosphate (dbcAMP), 3-isobutyl-1-methyl-xanthine (IBMX), and cholera toxin (CT) were then applied to DA-1ER cells to see whether they could induce cell growth, but none of them was effective. The data indicated that cAMP was not the so-called second messenger for Epo or IL-3. The regulatory effects of cAMP on Epo- and IL-3-stimulated cell growth were next examined. It was found that whereas Epo-stimulated growth was markedly inhibited by cAMP-enhancing agents, IL-3-stimulated growth was relatively resistant and inhibited only by high doses of these agents. These data suggested that cAMP could play different roles in the same cells, depending on which growth factors were applied, and that it finely regulated proliferation and differentiation of multireceptor-bearing hematopoietic precursor cells.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Highly sensitive enzyme immunoassay for bovine chromogranin A: application for studies of regional distribution in bovine central nervous system.

Bovine chromogranin A (CGA) was purified by three steps of column chromatography to a single-band purity in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antibody against this preparation was purified by a CGA-coupled Sepharose column, and F(ab')2 and Fab' of the antibody IgG were prepared by enzymatic digestion. An enzyme immunoassay (EIA) system was developed with the F(ab')2 immobilized on polystyrene balls and the Fab' labeled with beta-D-galactosidase. The EIA was able to detect 1 pg of CGA and was three to four orders more sensitive compared with any radioimmunoassay systems hitherto reported. Several neural acidic proteins (dopamine beta-hydroxylase, neuron specific enolase, S-100a protein, and brain-type creatine kinase) showed no cross-reaction. Using this EIA, CGA was detected in all regions of bovine central nervous system. CGA concentrations were within a narrow range, being lowest in the cerebellar white matter and highest in the putamen (17.3 and 78.1 ng/mg protein, respectively). The concentrations were extremely low compared to the concentration in the adrenal medulla (205,000 ng/mg protein). The highly sensitive EIA system should be useful for studies of materials containing very small amounts of CGA.

Animals↗
PubMed1989

[Glycosphingolipids affect on the functional properties of human lymphocytes--in relation to HIV-infection of lymphocytes].

Glycosphingolipids, which are functionally present on plasma membrane of mammalian cells, have a variety of functions in immune system such as surface markers of lymphocytes and mediators or modulators of the cells. Interestingly, gangliosides induced selective modulation of CD4, which is not only the subset marker of T-lymphocytes but also the receptor for human immunodeficiency virus. Here, we raised a process of endocytosis as a possible mechanism for the modulation of CD4. We also found that gangliosides inhibited HIV-infection in vitro.

Animals↗