[Toothbrushing before and after prosthodontic management].
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Adult↗
Biomedical subjects
T Tokunaga
Publications and source records attributed to T Tokunaga.
Cell surface markers to monitor the process of visceral endoderm differentiation from embryonal carcinoma cells: identification of the stage sensitive to high concentration of retinoic acid.
Two cell surface antigens, brushin and FT-1 were effective in analysis of the process of visceral endoderm differentiation. Brushin was detected on both primitive and visceral endoderm, while FT-1 was detected only on visceral endoderm. When aggregates of N4-1 embryonal carcinoma cells were exposed to 10(-8) M-retinoic acid for more than 2 days, external cells differentiated to multilayered and vacuolized visceral endoderm. However, aggregates treated with 10(-6) M-retinoic acid developed an endoderm layer, which remained one cell thick and was not vacuolized. Cell surface properties of the endoderm cells indicated that the high concentration of retinoic acid inhibited the differentiation pathway at the stage between primitive endoderm cells and visceral endoderm cells. By pulsed exposure to 10(-6) M-retinoic acid, the period sensitive to the high concentration of retinoic acid was shown to be around day 4 after the initial exposure to retinoic acid.
Animals↗
Synthesis and expression of the native RNase T1 gene and several mutant genes.
RNase T1 gene and several mutant genes were constructed by joining of chemically synthesized deoxyoligonucleotides. These genes were inserted into an expression vector and expressed as fused protein in E. coli. RNase T1 and its mutant enzymes were liberated by cyanogen bromide treatment and their activities were measured.
Amino Acid Sequence↗
A new differentiation antigen (FT-1) shared with fetal thymocytes and leukemic cells in the mouse.
A mouse monoclonal antibody (IgM) was obtained by cell hybridization between X63-Ag8.653 myeloma cells and spleen cells from a BALB mouse that was immunized with GRSL leukemia cells of the GR strain. This antibody identified a unique fetal antigen, which is expressed exclusively on embryonic thymocytes of all strains tested. Therefore, the antigen defined was named fetal thymus antigen-1, FT-1. The proportion of FT-1+ fetal thymocytes detected by immunofluorescence assay sharply decreases as gestation time increases, and finally they disappear from the thymus. On the other hand, Thy-1+ cells increase in inverse proportion. The immunofluorescence studies and absorption tests showed that FT-1 antigen is not detectable on brain, liver, kidney, or lymphoid tissue cells of adult mice. However, it is expressed on some leukemia cells of various mouse strains, which demonstrated that this is the first example of an oncofetal antigen of a mouse leukemia. The molecular weight of FT-1 antigen on leukemia cells was estimated to be 130,000 by means of biosynthetic labeling with [3H]galactose and [35S]methionine. The two-dimensional gel electrophoresis pattern of FT-1 antigen shows a family of glycoproteins with extensive charge heterogeneity. It was also shown that the FT-1 antigen molecule carries the receptor for DBA lectin.
Aging↗
Muscarinic cholinergic receptors in human gastric mucosa.
Muscarinic cholinergic receptor sites in human gastric mucosa were analyzed directly by using radioligand binding techniques with the specific muscarinic antagonist 3H-quinuclidinyl benzilate (QNB) as ligand. Specific binding of 3H-QNB to membrane preparations from human gastric mucosa was saturable, of high affinity (Kd = 4.17 +/- 1.94 nM, Bmax = 0.37 +/- 0.04 pmol/mg protein) and selectively inhibited by muscarinic antagonists (atropine, scopolamine) and agonists (acetylcholine, pilocarpine). These findings provide direct evidence for the existence of muscarinic cholinergic receptors in human gastric mucosa. The specific 3H-QNB binding to its receptor was blocked by atropine but not by histamine, cimetidine, pentagastrin, or synthetic human gastrin. The muscarine and histamine H2-receptor, or muscarine and gastrin receptor, probably do not share the same locus.
Acetylcholine↗
A specific gastrin receptor in human gastric mucosa.
Biological active 125I-synthetic human gastrin (125I- SHG ) appeared to bind specifically on human gastric mucosal membrane preparations. Gastrin binding was reversible, saturable and of high affinity (Kd = 3.44 +/- 3.44 X 10(-10)M) with the binding site (3.66 +/- 0.34 fmol/mg protein) at 37 degrees C for 30 min (pH 7.4). Specific gastrin binding was present in the fundic mucosa and absent from the antral, duodenal, jejunal, and colonic mucosa. Gastrin analogues (tetragastrin, pentagastrin, caerulein, and synthetic human gastrin) inhibited 125I- SHG specific binding. However, the specific gastrin binding was not inhibited by glucagon, insulin, acetylcholine, atropine, histamine, or cimetidine. It was suggested that gastrin and histamine H2 receptor or gastrin and muscarinic cholinergic receptor did not share the same locus.
Adenylyl Cyclases↗
Muscarinic and nicotinic effects on yawning and tongue protruding in the rat.
Physostigmine, an anticholinesterase agent, elicited yawning with a marked protrusion of the tongue and teeth chattering. Yawning and chattering were also observed after pilocarpine, a cholinergic agonist predominantly acting upon muscarinic receptors. Apomorphine at low doses (0.1-0.5 mg/kg), which preferentially activates presynaptic dopamine autoreceptors, elicited yawning, whereas at high doses (1-2 mg/kg) it produced stereotypy. Yawning induced by both cholinergic agonists and apomorphine was inhibited by scopolamine, a muscarinic receptor blocking agent, but not by methylscopolamine, a peripheral anticholinergic agent and mecamylamine, a nicotinic receptor blocking agent. Low dose (0.02 mg/kg) of haloperidol, which has been reported to block presynaptic dopamine autoreceptors, inhibited apomorphine-induced yawning but did not affect cholinergic agonist-induced yawning. Physostigmine-elicited tongue protruding was inhibited by mecamylamine. The results imply that yawning behavior is essentially associated with the stimulation of central muscarinic receptors, and that physostigmine also induces tongue protruding by activating the central nicotinic receptors.
Animals↗
Synthesis of a gene for human growth hormone and its expression in Escherichia coli.
A gene coding for human growth hormone, which consists of 192 amino acids, was chemically synthesized. The synthesis entailed ligating 78 deoxyribooligonucleotides, which had been synthesized on polymer supports by the phosphotriester method with frequently occurring amino acid codons of Escherichia coli. The chemically synthesized gene was inserted into an E. coli plasmid downstream from the E. coli trp promoter, with a modified ribosome-binding region carried on pBR322. E. coli cells transformed with this recombinant plasmid synthesized 2.9 X 10(6) molecules per cell of human growth hormone upon induction. The induced polypeptide was identical with natural human growth hormone in size and in immunological properties, as well as in biological activity as examined by the tibial test with hypophysectomized rats.
Amino Acid Sequence↗
Nondigestibility of a new sweetener, "Neosugar," in the rat.
The digestion of Neosugar, a mixture of 1F-(1-beta-fructofuranosyl)n-1 sucrose [n = 2, 1-kestose (GF2); n = 3, nystose (GF3); n = 4, 1F-beta-fructofuranosyl nystose (GF4)] was investigated in vitro and in vivo by using the rat. The results obtained were as follows. GF2 and GF3 were not hydrolyzed by a pancreatic homogenate. The GF2- and GF3-hydrolyzing activities of the enzymes in the intestinal mucosa homogenate were negligible compared with the activities of maltase and sucrase. GF2 and GF3 added to the incubation mixture did not affect the activities of sucrase and maltase in the intestinal mucosa. Long-term ingestion of Neosugar did not cause induction or suppression of GF2- and GF3-hydrolyzing enzymes in the small intestine. [U-14C]Neosugar injected intravenously was rapidly excreted in the urine without having undergone any degradation. These results indicate that Neosugar, which consists of GF2, GF3 and GF4, is scarcely hydrolyzed by the digestive enzymes of the gastrointestinal tract and internal organs, and that suggests to us that Neosugar is not utilized as an energy source in the body.
Animals↗
Two new fetal thymocyte antigens, FT-1 and FT-2.
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Animals↗
Genetic control of resistance to Mycobacterium intracellulare infection in mice.
The susceptibilities of various strains of mice to a highly pathogenic strain of Mycobacterium intracellulare, the Mino strain, were determined by intravenous injection of 5 X 10(6) bacteria. CFU were counted on days 1 and 21 of infection. Among 10 strains of mice, C57BL/6, C57BL/10, BALB/c, B10.BR, B10.A, and B10.D2 were susceptible, whereas DBA/2, A/J, CBA, and C3H/He were resistant. In the susceptible mouse strains, the number of bacteria increased during 21 days of infection, whereas no bacterial growth was observed in the resistant strains. Susceptible mice showed weak but positive delayed-type hypersensitivity to M. intracellulare purified protein derivative 20 days after injection of bacteria. Resistant mice developed no delayed-type hypersensitivity. Histological examination showed severe granulomatous lesions in livers or spleens of the susceptible mice after M. intracellulare injection. Analysis of F1 hybrids of susceptible and resistant strains and of F2 and backcross mice showed that the resistance to M. intracellulare seems to be controlled genetically by a single dominant gene. The pattern of distribution of resistance to M. intracellulare among the mouse strains was consistent with that of natural resistance to Mycobacterium bovis to BCG. Thus, resistance to M. intracellulare infection may be regulated by a gene linked to the Bcg gene on chromosome 1.
Animals↗
Antitumor activity of deoxyribonucleic acid fraction from Mycobacterium bovis BCG. I. Isolation, physicochemical characterization, and antitumor activity.
A fraction extracted from Mycobacterium bovis strain BCG, which was composed of 70.0% DNA, 28.0% RNA, 1.3% protein, 0.20% glucose, and 0.1% lipid and of no detectable amounts of cell wall components such as alpha, epsilon-diaminopimelic acid and hexosamine, was found to possess strong antitumor activity. Repeated intralesional injection of this fraction, designated MY-1, without attachment to oil or a single intralesional injection of MY-1 emulsified in mineral oil caused the IMC carcinoma of CDF1 mice and line 10 tumor of strain 2 guinea pigs to regress and/or prevented metastasis very effectively. MY-1 after digestion with RNase, which contained 97.0% single-stranded DNA with a guanine-cytosine content of 69.8%, was more effective than undigested MY-1 against IMC and line 10 tumor, while MY-1 digested with DNase, which contained 97.0% RNA, had reduced activity, suggesting that the DNA from BCG possessed strong antitumor activity under certain conditions. Details of the extraction procedures and physicochemical characterization of MY-1 were also described.
Animals↗
Synthesis and expression of RNase T1 gene.
In order to obtain knowledges about structure-function relationship of ribonuclease T1, we synthesized a structural gene for RNase T1 and several its modified genes. Using amino acid codons frequently used in Escherichia coli we designed genes consist of 328 X 2 bases. Synthesis of oligodeoxynucleotides with 9-20 base lengths was performed by 1% polystyrene supported triester approach and resulting 42 oligomers were joined together using T4 DNA ligase. The product was analyzed and utilyzed to construct expression vectors, which produced effectively fused proteins.
Amino Acid Sequence↗
Role of lymphokines in regulation of macrophage differentiation.
The regulatory mechanism of guinea pig lymphokines was investigated in regard to differentiation of myeloid cells to macrophages. The Ml-cell line, established from a myeloid leukemia of an SL-strain mouse, was induced to differentiate in vitro into mature macrophages possessing Fc receptors and the ability to phagocytize latex particles by treatment with crude lymphokines. Both concanavalin A- and antigen-induced lymphokines showed the differentiation-inducing factor (D factor) activity. However, macrophage migration inhibitory factor/ macrophage activation factor (MIF/MAF) purified by an immunoadsorbent column with anti-MIF antibody had no such an activity. The D-factor activity was detected in the lymphokine preparation that was not retained on the immunoadsorbent column. In contrast, colony-stimulating factor (CSF) was adsorbed to the immunoadsorbent column, and could be recovered in the purified MIF/MAF preparation. These findings suggest that the molecular entity of D factor is distinct from MIF/ MAF and CSF. A culture supernatant of guinea pig peritoneal macrophages activated with MIF/ MAF (CSF) exhibited strong D-factor activity. However, the supernatant possessed rather reduced CSF activity as compared to that of the original MIF/MAF (CSF) preparation. Thus, MIF/MAF may play an important role in macrophage differentiation by regulating the production of D factor or CSF from macrophages.
Animals↗
High-performance liquid chromatography of alpha-keto acids in human saliva.
alpha-Keto acids in human mixed saliva collected without stimulation were analysed by reversed-phase ion-pair high-performance liquid chromatography (HPLC). Several alpha-keto acids were found in saliva and their concentrations were: alpha-ketoglutaric acid (KGA), 221 +/- 142; pyruvic acid (PA), 7490 +/- 5600; alpha-ketoisovaleric acid (KIVA), 61 +/- 23; alpha-ketoisocaproic acid (KICA), 137 +/- 79; alpha-keto-beta-methylvaleric acid (KMVA), 41 +/- 19 nmol/dl (mean +/- SD, n = 40). Their levels proved to be lower than those in plasma, except that of PA. Their concentrations in saliva showed individual variation compared with those in blood.
Adult↗
NK cell activity in pulmonary tuberculosis.
Natural killer (NK) cell activity, which may provide defence mechanism in the immune surveillance system, was studied in 38 patients with active pulmonary tuberculosis and 54 sex-, and age-matched healthy controls. The mean NK cell activity in patients with active pulmonary tuberculosis (58.7 +/- 26.4%) was significantly higher (P less than 0.001) than that in healthy controls (17.4 +/- 12.2%). Classifying the patients into three groups according to the state of excretion of tubercle bacilli, the mean NK cell activity in newly diagnosed patients was 43.2 +/- 20.7%, in advanced disease 59.4 +/- 30.3%, and in successfully treated patients 71.9 +/- 25.9%.
Adult↗
Absence of detectable cytotoxic lymphocytes in the spleens of guinea pigs immunized with allogeneic cells.
Using inbred guinea pigs of strains JY 1, JY 2, 2 and 13, whose major histocompatibility gene complexes are different from each other at the B region and/or the I region, the authors aimed to detect cytotoxic thymus-derived lymphocytes (CTL) against allogeneic target cells. Various in vivo and in vitro sensitization methods that have been described for murine CTL systems were used. For detection of CTL, Con A- or PHA-induced 51Cr-labeled lymphoblasts were incubated with sensitized spleen cells or lymph node cells for 4 hr, and 51Cr released into the supernatant was assayed. Under these conditions, no significant lysis of the target cells was observed. On the other hand, significant levels of both delayed-type hypersensitivity and humoral antibodies were detected in the animals sensitized by in vivo methods.
Animals↗
Comparative studies with various substrains of Mycobacterium bovis BCG on the production of an antigenic protein, MPB70.
A protein, isolated and purified from the unheated culture filtrate of Mycobacterium bovis BCG (substrain Tokyo 172) and designated MPB70, elicited a delayed skin reaction in guinea pigs sensitized with viable cells of BCG but not in those sensitized with heat-killed cells. The skin reaction reached the maximum 4 to 8 weeks after the inoculation of the BCG and then decreased gradually, resulting in conversion to negative after 20 weeks, whereas the skin reaction to purified protein derivative (PPD) continued to be positive. Guinea pigs immunized with viable cells of various substrains of BCG were skin tested with MPB70 and PPD. Guinea pigs immunized with the BCG substrain Tokyo 172 and the substrain Moreau (Brazil) showed strong delayed skin reactions to both MPB70 and PPD. On the other hand, guinea pigs immunized with the Pasteur substrain 1173P2, the Glaxo substrain 1077, the Copenhagen substrain 1331, the Tice substrain, or the Beijing substrain 64-42 showed negative skin reactions to MPB70, whereas they were strongly positive to PPD. In a two-dimensional acrylamide gel electrophoretic analysis of proteins from the culture filtrates of the BCG substrains, the culture filtrates of the Tokyo and Moreau substrains showed the spot of MPB70 on the gel slabs, whereas those of the other BCG substrains did not.
Animals↗