Role of Hydrogen in C and Si (001) Homoepitaxy.
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Journal Article↗
Biomedical subjects
M Okazaki
Publications and source records attributed to M Okazaki.
Cloning and sequencing of the membrane-bound hydrogenase-encoding genes (hupS and hupL) from Pseudomonas hydrogenovora.
The membrane-bound hydrogenase (Hdg)-encoding structural genes were isolated from the hydrogen-utilizing bacterium Pseudomonas hydrogenovora (Ph). Nucleotide sequence analysis revealed two genes, hupS and hupL. The hupS gene encoded a 363-amino-acid (aa) polypeptide (40.4 kDa). The deduced aa sequence contained a putative 43-aa leader peptide sequence. The hupL gene started at 55 bp downstream from the stop codon of hupS and encoded a 622-aa polypeptide (69.3 kDa). The disruption of Ph hupS resulted in the loss of Hdg activity.
Amino Acid Sequence↗
rap1 p21 regulates the interaction of ras p21 with RGL, a new effector protein of ras p21.
We have recently found that ralGDS family members (RGL and ralGDS) are putative effector proteins of ras p21. rap1 p21 is a small GTP-binding protein which has the same amino acid sequence as the effector loop of ras p21. We examined the effect of rap1 p21 on the interaction of ras p21 with RGL. The GTP-bound form of rap1 p21 interacted with RGL as well as did ras p21. rap1 p21 inhibited the interaction of ras p21 with RGL. RGL was phosphorylated by cyclic AMP-dependent protein kinase (protein kinase A). Phosphorylation of RGL did not affect its binding to ras p21 and rap1 p21 under the conditions that phosphorylation of Raf-1 reduced its affinity for ras p21. These results demonstrate that rap1 p21 but not protein kinase A regulates the interaction of ras p21 with RGL and suggest that rap1 p21 and protein kinase A may cooperate to distinguish the signal or ras p21 to RGL from that to Raf-1.
Cloning, Molecular↗
Enhanced formation of isoamyl alcohol in Zygosaccharomyces rouxii due to elimination of feedback inhibition of alpha-isopropylmalate synthase.
Mutants of the 'miso' yeast, Zygosaccharomyces rouxii, that produced a large amount of isoamyl alcohol, an important flavour in miso fermentation, were isolated from 5,5,5-trifluoro-DL-leucine-resistant mutants, an analogue of L-leucine. One of the mutants, M21-10, produced a three-fold higher level of isoamyl alcohol than the wild-type strain MY21 in miso fermentation. The activity of alpha-isopropylamalate synthase, one of the enzymes used for L-leucine synthesis, in the mutant M21-10 was not inhibited by the addition of L-leucine, a feedback inhibitor.
2-Isopropylmalate Synthase↗
Cell death of human multinucleated giant macrophages induced by conditioned medium obtained from rat liver cells.
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Animals↗
Glycine-to-arginine substitution at codon 145 of HBsAg in two infants born to hepatitis B e antigen-positive carrier.
Two daughters born to an HBeAg-positive carrier became hepatitis B virus carriers despite immunoprophylaxis with hepatitis B immune globulin or hepatitis B vaccine. The elder daughter received hepatitis B immune globulin alone and the younger daughter received both hepatitis B immune globulin and hepatitis B vaccine. They acquired anti-HBs passively immediately after birth, and the younger daughter did not respond to active immunization. The nucleotide sequence of the S gene of hepatitis B virus DNA from the four carriers in the family was determined. A 531-bp fragment within the S gene, which includes a region encoding both the common a and type-specific d/y or r/w determinants, was amplified by polymerase chain reaction and sequenced. Antigenic subtypes of HBV were identified as adr in the father and adw in both the mother and two daughters. Amino acid residues 122-160 of HBsAg were identical between the daughters and their mother except for a glycine-to-arginine substitution at codon 145. A possibility that this escape mutant had selective advantage over wild-type hepatitis B virus under immune pressure is discussed.
Amino Acid Sequence↗
"Rebound" phenomenon of hepatitis C viremia after interferon therapy in "relapsed" patients with chronic hepatitis C.
The correlation between serum hepatitis C virus (HCV)-RNA and aminotransferase levels following completion of interferon therapy was evaluated in eight relapsed patients with chronic hepatitis C. Both HCV-RNA and aminotransferase levels were significantly increased in the relapsed patients 1 month after completion of therapy, compared to pretreatment values, despite aminotransferase levels being normal and HCV-RNA being undetectable by reverse transcription polymerase chain reaction assay at the end of therapy. The serum levels of HCV-RNA and aminotransferase were significantly elevated 1 and 2 months post-treatment. They then decreased to pretreatment values 3-5 months after the completion of therapy. Thus, in relapsed patients after the completion of therapy, the changes in HCV-RNA levels preceded the elevation in aminotransferase levels. These findings suggest a correlation between serum HCV-RNA levels and aminotransferase levels in relapsed patients with chronic hepatitis C after the completion of interferon therapy.
Adult↗
Space-cutting model of hydroxyapatite.
The possibility of substitution of trace elements such as Mg2+, Sr2+ and Ba2+ into the columnar Ca2+ positions of hydroxyapatite was examined by computer graphics with a personal computer and a space-cutting method. Data on the structural coordinates of the hydroxyapatite were put into a protein graphics program in Angstrom units. The connection of each element, with front and rear, was displayed by the shade-line erasing method, and the solidity of the image was expressed by the degree of lightness from the light source. The space-cutting model was obtained by selecting the cutting plane with three atoms in the crystal. Rotating the graphics freely around the X, Y and Z axes gives a view from any direction. The computer graphics suggested visually how the lattice dimensions expand with Sr2+ and Ba2+ substitution and contract with Mg2+ substitution.
Algorithms↗
Transmission electron microscopic observation of heterogeneous fluoridated hydroxyapatites.
Two different types of heterogeneous fluoridated hydroxyapatites previously synthesized at 80 degrees C and pH 7.4, which might be composed of hydroxyapatite covered with fluorapatite (H-FAp) and fluorapatite covered with hydroxyapatite (F-HAp), were observed by high-resolution transmission electron microscopy. The transverse-sectional shapes of both apatites were clearly hexagonal. This confirmed that both apatites were highly crystallized. However, their shapes differed slightly from each other in detail:H-FAp was more slender and F-HAp was typically hexagonal, probably reflecting the shapes of the original core apatites, hydroxyapatite and fluorapatite. The portions thought to be synthesized with fluoride-free solution showed clear electron beam damage. The expanded lattice image observed at the edge of the F-HAp crystal coincided approximately with the a-axis dimension of 0.9443 nm obtained from the X-ray diffraction data of synthetic hydroxyapatite. After incubation in 0.5 mol l-1 acetate buffer solution (37 degrees C, pH 4.0) for one month, the fluorapatite-covered H-FAp maintained its sharp corners, while the hydroxyapatite-covered F-HAp showed rounded corners.
Hydroxyapatites↗
Crystallographic properties of heterogeneous Mg-containing fluoridated apatites synthesized with a two-step supply system.
Mg-containing fluoridated hydroxyapatites (Mg-MgFAp and MgF-MgAp) were synthesized heterogeneously with two different modes of fluoride supply. The expanded (300) reflections of the X-ray diffraction of both apatites were broader than and different from those of the mechanical mixture of the homogeneous apatites (MgAp and MgFAp). Scanning electron microscopy (SEM) showed that the crystal size and shape of Mg-MgFAp and MgF-MgAp were different. Energy dispersive spectroscopy (EDS) indicated that the fluoride intensity of Mg-MgFAp synthesized with the fluoride supply in the latter half of the experimental period was higher than that of MgF-MgAp. The apparent solubility of Mg-MgFAp was lower than that of MgF-MgAp. These results suggested that two different types of Mg-containing fluoridated hydroxyapatites might be formed: surface fluoride-rich apatites (Mg-MgFAp) and inner fluoride-rich apatites (MgF-MgAp).
Crystallography↗
Detection of p53 gene mutations in aspiration biopsy specimens from suspected breast cancers by polymerase chain reaction-single strand conformation polymorphism analysis.
Genomic DNA was extracted from aspiration biopsy specimens taken from 15 suspected cases of breast cancer, including 7 known cases of breast cancer, and the p53 gene was studied for evidence of mutation by using a polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. In 5 of the 15 cases (33%), p53 gene mutation was identified and these tumors were subsequently histologically diagnosed as malignant. Further, DNA flow cytometry of the 15 tumors demonstrated that 6 (40%) were aneuploid and malignant, whereas 9 (60%) were diploid and benign. It was also found that the tumor cells in 5 aspirated cases that showed p53 gene mutations were all aneuploid, the p53 protein expression was positive, and the tumors were proved to be histologically malignant. It was thus concluded that the detection of p53 gene mutation by PCR-SSCP analysis of aspirated biopsy specimens from suspected breast cancers is a helpful method for achieving a more accurate diagnosis.
Adult↗
Giant cell tumors of tendon sheath: a single and multiple immunostaining analysis.
Nineteen giant cell tumors of tendon sheath (GCTTS) were studied to elucidate the origin of the proliferating cells of these tumors, using single and multiple immunostaining techniques with a labeled avidin-biotin [LAB] method in paraffin-embedded tissues. Proliferating cell nuclear antigen (PCNA) and Ki-67 (MIB-1) antigen were present in mononuclear cells (PCNA 26%; MIB-14%) but were absent in giant cells. These findings indicate that mononuclear cells, but not giant cells, participate in the proliferative compartment of GCTTS. A histiocytic marker, HAM56, was positive in many mononuclear cells (mean 81%), but was totally negative in osteoclastic giant cells. Another histiocytic antigen, CD68, was expressed in both mononuclear cells (mean 28%) and most of the giant cells (mean 89%). By triple immunostaining for PCNA, HAM56 and vimentin, 83% of PCNA-positive mononuclear cells co-expressed HAM56. Because of the frequent co-expression of PCNA and HAM56, the main portion of proliferating cells in GCTTS may represent a monocyte/macrophage lineage. However, there is a small but definite mesenchymal/fibroblastic component, characterized by PCNA+vimentin+HAM56-, relating to the proliferative compartment of GCTTS. Multiple immunostainings with MIB-1 showed similar patterns to those with PCNA. These observations indicate that the GCTTS represent bimodal proliferative lesions consisting of histiocytic and mesenchymal/fibroblastic elements.
Adolescent↗
Photochemistry of acetylenic ketones in micellar solutions as studied by product-yield-detected ESR and transient absorption techniques.
The electron spin resonance (ESR) spectra of the transient radical pairs in the photoreduction of 1,5-diphenyl-1,4-pentadiyn-3-one(I) and 1,3-diphenyl-2-propyn-1-one(II) in sodium dodecyl sulfate (SDS) micellar solutions have been obtained by using the product-yield-detected ESR (PYESR) technique. The PYESR spectra, detected by tracing the microwave effect on the spin-adduct yield as functions of the magnetic field, show the ESR spectra of the ketyl radical of the ketone and SDS radical as the components of the radical pairs. In addition, the growth and the decay processes of the radical pair were observed through detecting the effect of microwave pulse as functions of the delay period between a laser pulse and the off and on time, respectively, of a microwave pulse. The absorption spectra of transient species have also been obtained by using the laser flash photolysis technique. Through the analysis of these data and molecular orbital calculations, the role of acetylenic groups in the photoreactivity of acetylenic ketones is discussed.
Alkynes↗
Influences of immobilization and footshock stress on pharmacokinetics of theophylline and caffeine in rats.
The influences of immobilization and footshock stress on pharmacokinetics of theophylline (20 mg kg-1) and caffeine (30 mg kg-1) administered orally were examined in rats. The immobilization stress for 30 min or 1 h immediately after oral administration caused marked immobilization period-related decreases in plasma theophylline concentrations during the absorption phase, but did not affect plasma caffeine concentrations. The ka and Cmax values for theophylline were significantly decreased, and the tmax was significantly increased. On the other hand, when the immobilization stress was loaded for 1 or 3 h before the oral administration, the plasma theophylline or caffeine concentrations were not affected. The footshock stress for 30 min immediately after oral administration did not significantly decrease plasma theophylline concentrations during the absorption phase. These results suggest that the pharmacokinetics of theophylline are influenced by strong stress, possibly due to the inhibition of its absorption from the gastrointestinal tract, but the pharmacokinetics of caffeine are not influenced by stress, probably due to its central action.
Animals↗
Production of Two Chitosanases from a Chitosan-Assimilating Bacterium, Acinetobacter sp. Strain CHB101.
A bacterial strain capable of utilizing chitosan as a sole carbon source was isolated from soil and was identified as a member of the genus Acinetobacter. This strain, designated CHB101, produced extracellular chitosan-degrading enzymes in the absence of chitosan. The chitosan-degrading activity in the culture fluid increased when cultures reached the early stationary phase, although the level of activity was low in the exponential growth phase. Two chitosanases, chitosanases I and II, which had molecular weights of 37,000 and 30,000, respectively, were purified from the culture fluid. Chitosanase I exhibited substrate specificity for chitosan that had a low degree of acetylation (10 to 30%), while chitosanase II degraded colloidal chitin and glycol chitin, as well as chitosan that had a degree of acetylation of 30%. Rapid decreases in the viscosities of chitosan solutions suggested that both chitosanases catalyzed an endo type of cleavage reaction; however, chitosan oligomers (molecules smaller than pentamers) were not produced after a prolonged reaction.
Journal Article↗
Angiotensin II induces transcription and expression of alpha 1-adrenergic receptors in vascular smooth muscle cells.
Angiotensin II (ANG II) induces vascular smooth muscle contraction and functions as a growth factor stimulating vascular smooth muscle cell (VSMC) hypertrophy. We wondered whether ANG II might induce expression of alpha 1-adrenergic receptors (ARs) in cultured VSMCs, which would then potentially accentuate the effects of catecholamines in the cells. Rat VSMCs were preincubated with phenoxybenzamine to inactivate alpha 1-ARs; the cells were then treated with ANG II for 24 h. ANG II-treated cells expressed an increased number of alpha 1-ARs compared with controls, suggesting that ANG II increased the rate of alpha 1-AR synthesis. ANG II markedly induced accumulation of alpha 1A/D- and alpha 1B-AR mRNAs in a concentration- and time-dependent manner. This effect of ANG II was blocked by the specific ANG II-receptor agonist [Sar1-Ile8]ANG II. ANG II-induced accumulation of alpha 1A/D-AR mRNAs was completely abolished by transcriptional inhibitor actinomycin D. ANG II markedly increased the transcriptional rate of the alpha 1A/D-AR gene without changing stability of alpha 1A/D-AR mRNAs. Protein kinase C (PKC) activator 4 beta-phorbol 12-myristate 13-acetate also induced accumulation of alpha 1A/D-AR mRNAs, and PKC inhibitor H-7 completely blocked ANG II-induced accumulation of the alpha 1A/D-AR mRNAs. Neither the biologically inactive ANG II analogue des-Phe8-ANG II nor the calcium ionophores A-23187 and BAY K-8466 induced alpha 1A/D-AR mRNAs. Finally, ANG II preincubation increased alpha 1-AR agonist phenylephrine-stimulated expression of the c-fos gene.(ABSTRACT TRUNCATED AT 250 WORDS)
1-Sarcosine-8-Isoleucine Angiotensin II↗
Structure-activity relationship of (1-->3)-beta-D-glucans in the induction of cytokine production from macrophages, in vitro.
In a previous study, we reported that one of the gel-forming (1-->3)-beta-D-glucans, grifolan (from Grifola frondosa, GRN), stimulated cytokine production from macrophages in vitro. However, several other gel-forming (1-->3)-beta-D-glucans, such as sonifilan (SPG) and SSG, did not induce cytokine production from macrophages. The ultrastructure of gel-forming (1-->3)-beta-D-glucans, especially the triple- and single-helix, does not affect the cytokine-inducing activity. The action on tumor necrosis factor alpha (TNF alpha) release was correlated with the molecular weight of GRN, since the highest molecular weight fraction of GRN, Mr > or = 45000, exhibited the strongest activity. Although, native SSG (Mr > or = 2000000) did not induce cytokine production, chemical modification involving debranching of the side chain glucosyl residues of SSG resulted in TNF alpha inducing activity. These results suggest that the branching ratio and molecular weight of (1-->3)-beta-D-glucans are important factors for the production of cytokines from macrophages. GRN-inducible TNF alpha release was reduced by co-culturing with SPG, SSG, or the soluble beta-glucan, laminarin (LAM). Pretreatment alone with SPG or LAM was not sufficient for significant inhibition of GRN-inducible TNF alpha release. TNF alpha production induced with 50 micrograms/ml of zymosan (ZyM) was also reduced by addition of SPG, but TNF alpha production, stimulated with a higher concentration (100 micrograms/ml) of ZyM or with lipopolysaccharide (LPS), was not reduced significantly. The inhibitory effect of LAM on the uptake of GRN by RAW264.7 cells was not completely correlated with TNF alpha release. These results suggest that macrophages may incorporate beta-glucans through certain (1-->3)-beta-D-glucan-specific mechanisms and/or other endocytosis pathways, and that the beta-glucan-specific route is partially associated with cytokine production. In conclusion, TNF alpha release by macrophages is induced only by beta-glucans with high molecular weights and lower branching ratios, and the mechanism for the recognition of beta-glucans is multiple and assumed to be divided into several parts involving various cellular functions.
Adjuvants, Immunologic↗
Effects of exposure to cigarette smoke on intestinal propulsion in rats.
The effects of acute exposure to cigarette smoke and systemic administration of nicotine on intestinal propulsion were investigated in rats. The propulsive activity was measured as migration of charcoal powder in the intestine. This activity was suppressed by acute exposure (10 min) to cigarette smoke and by nicotine (0.5 mg/kg x 2, s.c.) administration. This intestinal suppression was more marked in the rats given nicotine than in those exposed to cigarette smoke, whereas the plasma concentrations of nicotine in both rats were similar. These results suggest that acute exposure to cigarette smoke and nicotine administration delay gastric emptying and/or suppress intestinal propulsion, and that some components other than nicotine contained in cigarette smoke may attenuate the suppression of intestinal propulsion induced by nicotine.
Animals↗