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S Tsuboi

Publications and source records attributed to S Tsuboi.

At least 19 recordsLinked to original sources
PubMed1995

Effect of stopping fluoride administration on the distribution profiles of fluoride in three different kinds of rat bones.

The aim of this work was to explore the reduction of fluoride concentrations in the skeleton after stopping experimental fluoride administration. Fluoride was administered to the rats at varying doses (0, 50, 100 ppm in drinking water) and for different lengths of time (4, 13, 25 weeks). A series of fluoride concentrations across the full thickness of humerus, parietal bone, and vertebra arch in rats were measured by means of an abrasive micro-sampling technique. The distribution profiles of fluoride from periosteal to endosteal surfaces, which were apparently related to the histological structure of these bones, were U shaped in the humerus, V shaped in the parietal bone, and W shaped in the vertebra arch. The average fluoride concentrations in the bones increased significantly with each increasing dose and length of fluoride administration. The relative increments were similar between the different regions or the different bones. After stopping fluoride administration, on the other hand, the relative reduction of the average fluoride concentrations in the bones were 30-100%. They were greatly related to the length after stopping fluoride administration and the dose and length of fluoride administration, but also dependent upon the type of bone and the region examined.

Animals↗
PubMed1995

Changes in levels of glutathione and related compounds and activities of glutathione-related enzymes during rat liver regeneration.

The levels of glutathione and glutathione disulfide increased during the regeneration process of rat liver, reaching a maximum (about twice the control value) on day 2 and reverting to the normal level within 5 days. During this regeneration process, changes in the hepatic level of cysteine, glycine and glutamate, the substrates for glutathione synthesis, were determined. The cysteine level in liver increased, reaching a maximum on day 2 and returned to the normal level after 5 days. The levels of glycine and glutamate did not change. The enzyme activities of cystathionine-beta synthase and gamma-cystathionase for cysteine synthesis, and of gamma-glutamylcysteine synthetase, which is a limiting enzyme for glutathione synthesis, were clearly increased in regenerating liver. The increase of glutathione level could be clearly accounted for by the elevation of these enzyme activities.

Animals↗
PubMed1995

[Desensitization immunotherapy on patients with mite-positive bronchial asthma using purified mite feces antigen fractions].

At present, we are performing desensitization immunotherapy on patients with mite-positive bronchial asthma using purified mite feces antigen fractions. We obtained the following results in 13 patients 4 to 12 months after the start of treatment. 1) The fraction showing the maximum reaction in the skin test was HM1-2 (molecular weight: 150-155 kD) in two patients, HM2 (30-40 kD) in nine patients and HM3 (10-20 kD) in two patients, and immunotherapy was performed using these fractions. None of the patients showed the maximum skin reactions or was treated with HM4 (less than 10 kD). 2) In nine patients with perennial asthma, the effects of treatment were excellent in four and moderate in three, while two cases remained unchanged. In four patients with seasonal asthma, the treatment was effective in all cases. 3) In patients in whom immunotherapy was effective, specific IgG antibody increased after the treatment, but it did not increase in the unchanged cases. Among the subclasses of specific IgG antibody increased by the treatment, no clear changes were seen in IgG4 antibody and no conclusion has been reached at present. 4) None of the patients had definite adverse reactions such as the occurrence of asthma attacks or anaphylaxis. These results suggested that purified mite feces antigens are safe and effective. We plan to continue this study with more patients in the future.

Adolescent↗
PubMed1994

Expression of distinct fucosylated oligosaccharides and carbohydrate-mediated adhesion efficiency directed by two different alpha-1,3-fucosyltransferases. Comparison of E- and L-selectin-mediated adhesion.

Among five different human alpha 1 --> 3 fucosyltransferases cloned, fucosyltransferases III (Fuc-TIII) and IV (Fuc-TIV) differ significantly from each other. Fuc-TIII transfers a fucose to both sialylated and nonsialylated N-acetyllactosamine, but Fuc-TIV apparently transfers a fucose only to neutral N-acetyllactosamine. In this study, Chinese hamster ovary (CHO) cells were stably transfected with Fuc-TIII or Fuc-TIV, and the resultant cell lines, CHO-FTIII and CHO-FTIV, were compared for the carbohydrate structures and for their binding to E-selectin or L-selectin. CHO-FTIII and CHO-FTIV cells were labeled metabolically with [3H]galactose, and glycopeptides obtained from these cells were fractionated by serial lectin affinity chromatography. The fractionated glycopeptides were then subjected to various combinations of exoglycosidase treatment or endo-beta-galactosidase digestion. The results obtained can be summarized as follows. CHO-FTIII cells express sialyl Lewisx, Lewisx, and VIM-2 structures, whereas CHO-FTIV cells express only an Lex structure with a small amount of VIM-2 structure. When CHO-FTIII and CHO-FTIV cells were tested for adhesion to E-selectin expressed by tumor necrosis factor-activated endothelial cells and to an E-selectin chimeric protein, only CHO-FTIII cells were found to adhere well to E-selectin. Moreover, both CHO-FTIII and CHO-FTIV cells failed to adhere to an L-selectin chimeric protein. These results clearly indicate that FT-III and FT-IV direct distinctly different fucosylated oligosaccharides. This difference in oligosaccharide structures results in an entirely different efficiency in adhesion to E-selectin. The results also demonstrate that expression of sialyl Lex itself is not sufficient for L-selectin binding.

Animals↗
PubMed1994

Phosphorylation of an inhibitory subunit of cGMP phosphodiesterase in Rana catesbeiana rod photoreceptors. II. A possible mechanism for the turnoff of cGMP phosphodiesterase without GTP hydrolysis.

In amphibian rod photoreceptor membranes, P gamma, an inhibitory subunit of cGMP phosphodiesterase, is phosphorylated by a protein kinase when P gamma is complexed with the guanosine 5'-O-(3-thiotriphosphate)-bound alpha subunit of transducin (GTP gamma S.T alpha). Five different experiments support the conclusion that the phosphorylated P gamma loses its interaction with GTP gamma S.T alpha. These observations include 1) detection of the inhibitory effect of the GTP gamma S.T alpha.P gamma complex on cGMP phosphodiesterase activity after P gamma in the complex is phosphorylated in a system reconstituted from isolated components, 2) no stimulating effect of GTP gamma S.T alpha on the phosphorylated P gamma-inhibited cGMP phosphodiesterase in the reconstituted system, 3) physical release of phosphorylated P gamma from GTP gamma S.T alpha in the reconstituted system, 4) no inhibitory effect of phosphorylated P gamma on both GTP hydrolysis by T alpha and GTP gamma S/GDP exchange on T alpha in the reconstituted system, and 5) no enhanced activity of cGMP phosphodiesterase by GTP gamma S.T alpha in rod outer segment membranes after incubation of the membranes with the kinase preparation in the presence of ATP. Together with our data that P gamma released with GTP.T alpha is not phosphorylated, and that phosphorylated P gamma inhibits more effectively cGMP phosphodiesterase activity than nonphosphorylated P gamma (Tsuboi, S., Matsumoto, H., Jackson, K. W., Tsujimoto, K., Williams, T., and Yamazaki, A. (1994) J. Biol. Chem. 269, 15016-15023), these observations suggest that, after P gamma is released with GTP.T alpha from catalytic subunits of cGMP phosphodiesterase, P gamma complexed with GTP.T alpha is phosphorylated by a kinase. Then, the phosphorylated P gamma is released from GTP.T alpha and binds to active cGMP phosphodiesterase to inhibit the cGMP hydrolysis. It is suggested that in some G-protein-dependent signal transduction systems G-protein-activated effector may be phosphorylated with a specific kinase and that phosphorylation of the effector results in the turnoff of signal transduction without GTP hydrolysis.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1994

Phosphorylation of an inhibitory subunit of cGMP phosphodiesterase in Rana catesbeiana rod photoreceptors. I. Characterization of the phosphorylation.

Interaction between the inhibitory subunit (P gamma) and catalytic subunits of cGMP phosphodiesterase is essential for the regulation of cGMP phosphodiesterase in vertebrate rod photoreceptors. P gamma phosphorylation in vitro has been studied using a kinase which is extracted from amphibian rod outer segments. Various chromatographies of the kinase preparation using ionic exchange, gel filtration, and heparin-Sepharose columns indicate that a kinase with M(r) 70,000 is responsible for the P gamma phosphorylation. The kinase does not require any of the known activators for protein kinases but is inhibited by cGMP in a concentration-dependent manner. Together with analysis by laser-desorption mass spectrometry, measurement of 32P radioactivity in phosphorylated P gamma indicates that P gamma extracted with GTP-bound transducin alpha subunit is not phosphorylated and that a phosphate is incorporated into more than 80% of the P gamma by the kinase. Phosphoamino acid analysis, sequencing of phosphorylated peptides derived from phosphorylated P gamma, and phosphorylation of synthetic peptides indicate threonine 22 in P gamma is phosphorylated by the kinase. Phosphorylated P gamma has a higher inhibitory activity for active cGMP phosphodiesterase than non-phosphorylated P gamma. These data suggest that threonine 22 in P gamma is phosphorylated by a specific kinase and that the P gamma phosphorylation governs the interaction between P gamma and catalytic subunits of cGMP phosphodiesterase in vertebrate rod photoreceptors.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1994

Differential E-selectin-dependent adhesion efficiency in sublines of a human colon cancer exhibiting distinct metastatic potentials.

Previously we have shown that high metastatic colonic carcinoma cells express relatively more lamp molecules and sialyl Le(x) structures on the cell surface than their corresponding low metastatic counterparts (Saitoh, O., Wang, W.-L., Lotan, R., and Fukuda, M. (1992) J. Biol. Chem. 267, 5700-5711). In the present study, we extended these findings by testing whether these high and low metastatic colonic carcinoma cells differ in their adhesion efficiency to E-selectin-expressing cells. First, it was found that the high metastatic cells, as compared to their low metastatic counterparts, bind more efficiently to activated human endothelial cells that express E-selectin. This was also true when the adhesion was tested for Chinese hamster ovary cells stably expressing E-selectin. In addition, it was found that the high metastatic cells also adhere more efficiently to mouse endothelioma cells after activation with interleukin-1 beta. It was also shown that the adhesion can be inhibited by soluble lamp-1 or soluble leukosialin that contain sialy Le(x) termini. The inhibition was not, however, observed when these soluble glycoproteins lack sialyl Le(x) structures. The results indicate that the efficiency of the E-selectin-mediated binding of colonic carcinoma cells to human and mouse endothelial cells correlates with the metastatic potential of the cells and suggest that this adhesive event may be one of the critical factors for the metastatic spread of tumor cells. Soluble forms of leukosialin or lamp-1 may be useful as therapeutic agents for the inhibition of E-selectin-mediated binding to tumor cells.

Animals↗
PubMed1994

Increase in production of hepatocyte growth factor by human embryonic lung fibroblasts in the process of aging in culture.

It was determined whether human hepatocyte growth factor (hHGF)-producing ability would change in the human embryonic lung fibroblast cell strains (MRC-5 and IMR-90) until the cells senesced in culture. The effects of phorbol 12-myristate 13-acetate (PMA), dexamethasone, and transforming growth factor-beta 1 (TGF-beta 1) on hHGF production were also studied in these cell strains. For stimulation of DNA synthesis of adult rat hepatocytes in primary culture, hHGF secreted by MRC-5 cells at 39.9 and 69.8 population doubling levels (PDLs) showed almost the same activity as recombinant hHGF. Secretion of hHGF by MRC-5 cells increased about threefold between 37.3 and 67.8 PDLs. IMR-90 cells also showed about a threefold increase in hHGF secretion with increased passage from 37.8 to 66.0 PDL. Both cell strains showed almost the same ratio of hHGF amount in the cell extracts to that secreted into the medium around 40 and 70 PDLs. Northern blot analysis showed that the transcriptional level of the hHGF gene in MRC-5 cells increased about three-fold from 42.0 to 73.6 PDL in culture. These findings indicated that hHGF production increased in both cell strains with aging in culture. Production of hHGF in both cell strains was remarkably stimulated by treatment with 10 nM PMA. On the other hand, hHGF production in both cell strains was slightly suppressed by treatment with 1 microM dexamethasone. TGF-beta at a concentration of 5 ng/ml prominently inhibited hHGF production in both cell strains. The response of both cell strains to these regulators for hHGF production was almost the same around 40 and 70 PDLs in culture.

Animals↗
PubMed1994

Magnesium distribution in human bone.

The present study was undertaken to reveal the magnesium distribution in human bone. Sixty human ribs, obtained from subjects aged 10-80 years of age, were used. Transverse sections were prepared from the middle region of the human ribs. Adjacent sections were ground to a thickness of about 1000 microns. One section was used for magnesium determination by atomic absorption spectrophotometry, and the other was used for analysis with X-ray microanalysis. Thirty micron thick samples were abraded continuously from the periosteal and the endosteal surfaces by abrasive microsampling, as previously described by Weatherell et al. Results showed that magnesium concentrations were higher in both the periosteal and endosteal surfaces and did not change with age in general, although it tended to be higher among teenagers and lower over 80 years old.

Adolescent↗
PubMed1994

Fluoride profiles in different surfaces of human permanent molar enamels from a naturally fluoridated and a non-fluoridated area.

The surfaces, sites and depths of fluoride profiles of enamel from a naturally fluoridated area (West Hartlepool, WHP, 1.9 parts/10(6) F in drinking water) and a non-fluoridated area (Leeds, LDS, < 0.1 parts/10(6) F in drinking water) were examined in detail. Using a regression curve, y = ax-b, comparisons of fluoride concentrations were made at depths of 1, 3, 5, 10, 20 and 30 microns at occlusal, middle and cervical sites of buccal, lingual, mesial and distal molar enamel surfaces. In the outermost enamels (< 10 mu in depth), fluoride concentrations tended to be lower in the occlusal sites than in the cervical sites. In interior enamels (> 20 microns in depth), the fluoride concentrations of molars from WHP were statistically higher than those from LDS, while few significant differences were found in the outermost layers. In the mesio- and disto-occlusal sites of approximal surfaces, there were some significant differences in the exponential regression coefficients of fluoride profiles between the two groups of molars.

Dental Enamel↗
PubMed1994

Comparative study of intraocular lens implantation through 3.2- and 5.5-mm incisions.

PURPOSE: To prospectively and comprehensively compare the clinical results of two small-incision cataract surgery procedures, silicone intraocular lens (refractive index of 1.46) implantation through a 3.2-mm incision and polymethylmethacrylate intraocular lens implantation through a 5.5-mm incision. METHODS: Two hundred eyes with cataract randomly were assigned to either procedure. Except for incision size, identical surgical methods were used in every case. Data on uncorrected and corrected visual acuity, keratometry, corneal topography, flare-cell measurement, fluorophotometry, specular microscopy, glare disability measurement, and photographic examination of intraocular lens decentration were analyzed up to 6 months after surgery. RESULTS: Eyes in the 3.2-mm incision group displayed significantly better uncorrected and corrected visual acuity in the early postoperative period, lower aqueous flare intensity and cell counts immediately after surgery, less operatively induced astigmatism throughout the study period, and less corneal topographic changes taken 3 months after surgery. No significant between-group differences were noted for other parameters. Complications in the two groups were few and comparable. CONCLUSION: Both procedures of small-incision cataract surgery offered satisfactory clinical results, but 3.2-mm incision cataract surgery allowed significantly earlier recovery of visual function and better preservation of corneal shape.

Aged↗
PubMed1994

Amino acids and peptides. XXXVII. Synthesis of stereoisomeric nonapeptides corresponding to sequence 41-49 of eglin c and examination of their inhibitory activity against human leukocyte cathepsin G and alpha-chymotrypsin.

A nonapeptide, H-Ser-Pro-Val-Thr-Leu-Asp-Leu-Arg-Tyr-OH, corresponding to sequence 41-49 of eglin c inhibited leukocyte cathepsin G and alpha-chymotrypsin with Ki values of 2.2 x 10(-5) and 7.2 x 10(-6) M, respectively, although eglin c itself inhibited leukocyte elastase, cathepsin G and alpha-chymotrypsin with Ki values of 6.0 x 10(-9), 5.5 x 10(-9) and 2.5 x 10(-9) M, respectively. The inhibitory activity of the nonapeptide decreased following incubation with cathepsin G due to the cleavage of the Leu45-Asp46 peptide bond. Therefore, Leu45 and/or Asp46 were replaced with D-amino acids and the inhibitory activities of the resultant nonapeptides were examined. Their inhibitory activities against cathepsin G and alpha-chymotrypsin were much weaker than those of the all-L-type nonapeptide, suggesting that the amino acids at the active site, Leu45 and Asp46 are required to be in the L-configuration for potent activity.

Amino Acid Sequence↗
PubMed1994

Differences in protein structure and similarities in catalytic function of two L-stereoselective carbonyl reductases from bakers' yeast.

We purified and studied two L-stereoselective carbonyl reductases from bakers' yeast (Saccharomyces cerevisiae). One catalyzed exclusively the enantioselective reduction of carbonyl compounds such as beta-keto esters and the other acted on alpha-acetoxy ketones and beta-keto esters. The enzymes had identical molecular weights and catalyzed the L-stereoselective reduction of various carbonyl compounds with similar substrate specificity, but they were different proteins coded by different genes.

Alcohol Oxidoreductases↗
PubMed1994

Low-molecular-size allergens, LM-1s, in feces extract of Dermatophagoides farinae which elicit histamine release from washed blood cells of patients with bronchial asthma.

A significant activity to elicit histamine release was found in an ultrafilterable (Mr-cutoff < 10 kD) fraction of a mite feces extract from a spent mite medium. The activity was divided into two fractions (LM1 and LM2) on an Ultrogel AcA 54 column when monitored by histamine release assay using washed peripheral blood cells from mite-allergic patients. The larger-molecular-size antigen, LM1 was further separated into three allergenic fractions by consecutive chromatography on Sephadex G-50, GM-DEAE, and TSKgel ODS-120T. All the purified allergens, LM1s (LM1a, LM1b, and LM1c), which produced positive reactions in skin tests on allergic patients, were glycoproteins (molecular weight: 8 kD on SDS-PAGE; 12.5 kD on Gel filtration) with different carbohydrate contents and pI values ranging from 4 to 5 on an IEF plate. LM1s were cross-reactive with anti-Der f II but not with anti-Der f I. The reaction of LM1c to anti-Der f II serum was completely inhibited with the other antigens, while the reactions of LM1a and LM1b to the serum were partially inhibited with LM1c or the other antigens, respectively.

Allergens↗
PubMed1994

A low-molecular-size LM2 allergen in mite, Dermatophagoides farinae, extracts containing feces which elicits conjunctival reactions in patients with bronchial asthma.

A low-molecular-size antigen, LM2, which possesses a significant activity to elicit histamine release, was isolated from an ultrafilterable (Mr-cutoff < 10k) fraction of a mite extract containing feces by consecutive chromatography on Ultrogel AcA 54 and Sephadex G-25. The isolated antigen was still heterogeneous glycoproteins, giving a smeary band around pI 3-5 on an Ampholine PAG plate, with molecular weights of 6-8k and 4k on SDS-PAGE and Sephadex G-50 gel filtration, respectively. Chemical treatments of the antigen suggested that the epitope responsible for the elicitation of histamine release resided in the protein moiety. The antigen had activities to provoke conjunctival congestion and histamine release in mite-allergic patients, but not immunogenicity by itself. The antigen competitively inhibited the reactions of HM1, HM2, and HM3 fractions to corresponding antisera, but did not cross-react with anti-Der f I or anti-Der f II sera.

Allergens↗
PubMed1994

[Refractive changes following cataract extraction with intraocular lens implantation].

Refractive changes after six cataract surgery procedures with intraocular lens implantation were assessed; namely, (1) 11 mm incision with running suture closure (n = 25 eyes), (2) 6.5 mm incision with running suture closure (n = 23). (3) 6.5 mm incision with horizontal suture closure (n = 21), (4) 6.5 mm incision without suture closure (n = 40), (5) 5.5 mm incision without suture closure (n = 46), and (6) 3.2 mm incision without suture closure (n = 46). The axis-based keratometric cylinder, absolute value of the induced cylinder vector, and spherical equivalent of the refractive power were analyzed up to 6 months after surgery. Refractive changes did not reach a stable state at 3 months postoperatively for the 11 mm and 6.5 mm running suture closure groups, but they stabilized at 3 months postoperatively for the 6.5 mm horizontal suture and sutureless closure groups, at 1 month postoperatively for the 5.5 mm sutureless closure group, and at 2 weeks postoperatively for the 3.2 mm sutureless closure group. It is concluded that the timing of refractive stabilization differs significantly among procedures, and smaller incisions with wound closure methods which do not exert a vertical force cause fewer postoperative refractive changes.

Aged↗
PubMed1994

[Small incision cataract surgery-silicone intraocular lens vs polymethylmethacrylate intraocular lens].

We compared the postsurgical results of two small incision cataract surgery procedures: silicone intraocular lens implantation through a 3.2 mm incision and polymethylmethacrylate intraocular lens implantation through a 5.5 mm incision. One hundred fifty eyes of 124 patients were randomly assigned to either procedure, and the patients underwent phacoemulsification and intraocular lens implantation without sutures or scleral cautery. Identical surgical techniques were employed in each case except for the size of the incision. Patients in the 3.2 mm incision group showed: (1) better uncorrected and corrected visual acuity in the early postoperative period, (2) lower aqueous flare intensity immediately after surgery, (3) less operatively induced corneal astigmatism throughout the study period up to 3 months after surgery, and (4) less corneal topographic change, i.e., less corneal flattening, 3 months after surgery. There were no significant differences between groups in the corneal endothelial cell loss, blood-aqueous barrier permeability measured by fluorophotometry, or postoperative complications. It was concluded that both procedures offer highly satisfactory clinical results, but that the 3.2 mm incision surgery allows a significantly earlier recovery of visual function and less surgery-induced corneal astigmatism.

Aged↗