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Biomedical subjects

Y Shimizu

Publications and source records attributed to Y Shimizu.

At least 91 records · Page 5Linked to original sources
PubMed2002

Regenerative repair of the mandible using a collagen sponge containing TGF-beta1.

INTRODUCTION: Alveolar bone resorption and atrophy of the mandible are a major challenge for regeneration medicine. In the present investigation, a collagen sponge that contained TGF-beta1 was placed at a mandibular defect and the osteogenic effects of collagen-TGF-beta1, complex were evaluated. MATERIAL AND METHODS: The Pm2, Pm3, and Pm4 teeth on both sides of the mandibles of 12 adult beagle dogs (9.0-12.0 kg) were extracted. After the extraction-site wounds healed, a bone defect (10.0 x 15.0 mm-wide, 10.0 mm-deep or 10.0 x 10.0 mm-wide, 10.0 mm-deep) was created on the mandible. A collagen sponge (10.0 x 10.0 x 10.0 mm) that contained TGF-beta1 (1.0 microg, 5.0 microg, or 10.0 microg, in physiological saline) was placed at the bottom of the defect and the overlying mucous membrane was sutured with 4-0 prolene. As a control, a collagen sponge that contained physiological saline only was placed in a defect on the opposite side. Two weeks after the surgery the wounds above the bone defects on both the control and TGF-beta1-treated sides had healed completely. RESULTS: At four, six, or eight weeks post-operatively animals were killed. Soft X-ray and bone-salt measurement analyses confirmed clearly that there was greater calcified bone formation in the defects into which TGF-beta1 had been incorporated than with the control defects. The implanted collagen sponges were fully resorbed and the bone tissue had regenerated from the bottom of the defects on the TGF-beta1, side by four weeks. On the control side, no such regeneration was observed. CONCLUSIONS: These results indicate that TGF-beta1, released slowly from a collagen sponge was effective in promoting bone remodeling when applied to mandibular defects in adult dogs.

Alveolar Bone Loss↗
PubMed2002

Surface expression of toll-like receptor 4 on THP-1 cells is modulated by Bu-Zhong-Yi-Qi-Tang and Shi-Quan-Da-Bu-Tang.

Human Toll-like receptor 4 (TLR4) has recently been identified and has been shown to be the main protein involved in recognizing Gram-negative bacteria. We examined the regulation of TLR4 surface expression in a human monocytic cell line (THP-1 cells) by two traditional Chinese herbal medicines. Bu-Zhong-Yi-Qi-Tang (TJ-41) and Shi-Quan-Da-Bu-Tang (TJ-48). TJ-41 and TJ-48 upregulated TLR4 surface expression in THP-1 cells, as well as enhanced TLR4 surface expression in these cells both dose- and time-dependently. These findings suggest that TJ-41 and TJ-48 increase the receptor involved in the response to Gram-negative bacteria and may enhance defenses against these pathogens.

Animals↗
PubMed2002

Increased levels of platelet-associated immunoglobulin G in a patient with mixed connective tissue disease.

We report the case of a 71-year-old Japanese woman with mixed connective tissue disease and increased levels of platelet-associated immunoglobulin G. After administration of oral prednisolone, platelet-associated immunoglobulin G levels decreased with a simultaneous increase in the number of platelets, suggesting that the thrombocytopenia observed in this patient was mediated by immune mechanisms. This is the first reported case of increased platelet-associated immunoglobulin G levels in a patient with mixed connective tissue disease.

Aged↗
PubMed2002

Effect of solution parameters on the removal efficiency of humic substances by a reuse material.

This paper provides an overview of the ability of polypropylene (PPL), a synthetic polymeric adsorbent made from reused plastic material. The removal of humic substances (HS) in a solution pretreated with dedoxyltrimethylammoniumbromide (DDTMAB), a cationic quaternary ammonium compound (QAC), was studied under various conditions. The removal of HS was achieved in its solute complexed form but also as suspended solids. The conditions of the HS solution, which fluctuation was suspected to have an impact on the performance of the adsorbent, were tested. The parameters investigated included the pH, the initial concentration of the surfactant, and the presence of suspended solids in solution. The results of the laboratory scale experiments showed that PPL removal efficiency of HS is strongly pH dependant with higher removal achieved at pH greater than 7. However, the shift for pH above 7 induced an increase in the optimum doses of DDTMAB as more and more deprotonated HS become available to react with DDTMAB. Ionic strength did have the opposite effect: the increase of ionic strength by addition of NaCl decreased PPL removal of HS.

Adsorption↗
PubMed2001

Analysis of Ca(2+) currents in spermatocytes from mice lacking Ca(v)2.3 (alpha(1E)) Ca(2+) channel.

In mammalian male germ-line cells, low-voltage-activated (LVA) Ca(2+) current has been identified and its electrophysiological properties have been studied. To investigate whether alpha(1)2.3 (alpha(1E)) subunit of the voltage-dependent Ca(2+) channel codes for the LVA current, whole-cell patch clamp and following reverse transcription-polymerase chain reaction (RT-PCR) experiments were performed in pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice. Whole-cell current in acutely dissociated pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice displayed a typical profile of LVA Ca(2+) currents and kinetics with no significant differences. Single-cell RT-PCR revealed the expression of Cacna1g in the pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice in which LVA Ca(2+) currents were actually recorded. These results suggest that the Ca(v)2.3 channel makes no detectable contribution to the LVA Ca(2+) current in the pachytene spermatocyte. Instead, Ca(v)3 family such as Ca(v)3.1 may be the likely candidates responsible for the LVA currents in pachytene spermatocytes.

Animals↗
PubMed2001

Coupling of the TCR to integrin activation by Slap-130/Fyb.

SLAP-130/Fyb (SLP-76-associated phosphoprotein or Fyn-binding protein; also known as Fyb/Slap) is a hematopoietic-specific adapter, which associates with and modulates function of SH2-containing leukocyte phosphoprotein of 76 kilodaltons (SLP-76). T cells from mice lacking SLAP-130/Fyb show markedly impaired proliferation following CD3 engagement. In addition, the T cell receptor (TCR) in SLAP-130/Fyb mutant cells fails to enhance integrin-dependent adhesion. Although TCR-induced actin polymerization is normal, TCR-stimulated clustering of the integrin LFA-1 is defective in SLAP-130/Fyb-deficient cells. These data indicate that SLAP-130/Fyb is important for coupling TCR-mediated actin cytoskeletal rearrangement with activation of integrin function, and for T cells to respond fully to activating signals.

Actins↗
PubMed2001

Gelatin sheet incorporating basic fibroblast growth factor enhances healing of devascularized sternum in diabetic rats.

BACKGROUND: Poor healing of the sternum often limits the use of bilateral internal thoracic arteries (BITAs) after coronary bypass surgery in diabetic patients. We have reported that a gelatin sheet that incorporates basic fibroblast growth factor (bFGF) accelerates sternal healing after BITA removal in normal rats. This study evaluated the effects of the above method for sternal healing in diabetic animals. METHODS AND RESULTS: Diabetic Wistar rats with blood glucose levels >400 mg/dL and body-weight loss >20 g were established by a single intravenous injection of streptozotocin (55 mg/kg). After median sternotomy and BITA removal, 16 diabetic rats received either a gelatin sheet that incorporated bFGF (100 microg/sheet) on the posterior table of the sternum (FGF group, n=9) or no gelatin sheet (control, n=7). Peristernal blood flow, as measured by a noncontact laser Doppler 4 weeks after surgery in the FGF group, recovered to the preoperative level (106+/-10% versus 82+/-9%, P<0.01), and marked angiogenesis was also observed around the sternum in the FGF group (30.5+/-3.2 versus 15.8+/-2.7 vessels/unit area, P<0.01). Deep sternal wound complications developed in 5 control rats but only in 1 rat in the FGF group (P<0.05). In the FGF group, histological examination showed improved sternal healing (excellent in 6 rats and slow/poor healing in 3). Bone mineral content as assessed by dual-energy x-ray absorptometry was greater in the FGF group (75.9+/-18.1 versus 48.9+/-10.7 mg, P<0.05). Bone mineral density of the sternum was similar between the 2 groups. CONCLUSIONS: A gelatin sheet that incorporates bFGF may offset sternal ischemia and accelerate sternal bone regeneration and healing, even in diabetic patients.

Administration, Topical↗
PubMed2001

Accumulation of beta-catenin protein and mutations in exon 3 of beta-catenin gene in gastrointestinal carcinoid tumor.

The molecular basis of carcinogenesis in gastrointestinal carcinoid tumors is not well understood. To clarify the contribution of the Wnt/beta-catenin signaling to this type of carcinogenesis, we investigated 72 cases of gastrointestinal carcinoid tumor both immunohistochemically and by direct sequencing of beta-catenin. Accumulation of beta-catenin in the cytoplasm and/or nucleus was observed in 57 cases (79.2%). We also detected mutations in exon 3 of beta-catenin in 27 cases (37.5%) and one mutation in APC (1.4%). Our results suggest that alterations in the Wnt/beta-catenin signaling pathway may be involved in the development of gastrointestinal carcinoid tumors.

Carcinoid Tumor↗
PubMed2001

Vitamin A deprivation results in reversible loss of hippocampal long-term synaptic plasticity.

Despite its long history, the central effects of progressive depletion of vitamin A in adult mice has not been previously described. An examination of vitamin-deprived animals revealed a progressive and ultimately profound impairment of hippocampal CA1 long-term potentiation and a virtual abolishment of long-term depression. Importantly, these losses are fully reversible by dietary vitamin A replenishment in vivo or direct application of all trans-retinoic acid to acute hippocampal slices. We find retinoid responsive transgenes to be highly active in the hippocampus, and by using dissected explants, we show the hippocampus to be a site of robust synthesis of bioactive retinoids. In aggregate, these results demonstrate that vitamin A and its active derivatives function as essential competence factors for long-term synaptic plasticity within the adult brain, and suggest that key genes required for long-term potentiation and long-term depression are retinoid dependent. These data suggest a major mental consequence for the hundreds of millions of adults and children who are vitamin A deficient.

Adult↗
PubMed2001

Production of (4)(double Lambda)H hypernuclei.

An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.

Journal Article↗
PubMed2001

Toll-like receptor 2 and 4 surface expressions on human monocytes are modulated by interferon-gamma and macrophage colony-stimulating factor.

Human Toll-like receptor 2 (TLR2) and TLR4 are recently identified receptors. TLR4 was shown to be the main protein involved in recognizing Gram-negative bacteria, whereas TLR2 is apparently the key factor in responses to other types of microbial pathogens. We examined regulations of TLR2 and TLR4 surface expressions in human peripheral blood monocytes by interferon-gamma (IFN-gamma) and macrophage colony-stimulating factor (M-CSF). IFN-gamma up-regulated both TLR2 and TLR4, but enhanced the surface expression, on human peripheral blood monocytes of TLR4 more than that of TLR2. On the other hand, M-CSF up-regulated both TLR2 and TLR4 surface expression on human peripheral blood monocytes, with no change in the ratio of TLR2/TLR4 surface expression. These results indicate that IFN-gamma enhances receptors involved in the response to Gram-negative bacteria more than those involved in responses to other types of microbial pathogens, whereas M-CSF enhances the receptor response to Gram-negative bacteria in the same manner as to other types of microbial pathogens.

Adjuvants, Immunologic↗
PubMed2001

Cutting edge: T cell migration regulated by CXCR4 chemokine receptor signaling to ZAP-70 tyrosine kinase.

Chemokines regulate the homeostatic trafficking of lymphocytes and lymphocyte influx into sites of injury and inflammation. The signaling pathways by which chemokine receptors regulate lymphocyte migration remain incompletely characterized. We demonstrate that Jurkat T cells lacking the ZAP-70 tyrosine kinase exhibit reduced migration in response to the CXCR4 ligand CXCL12 when compared with wild-type Jurkat T cells. Expression of wild-type, but not kinase-inactive, ZAP-70 resulted in enhanced migration of ZAP-70-deficient Jurkat T cells. The tyrosine residue at position 292 in the interdomain B region of ZAP-70 exerts a negative regulatory effect on ZAP-70-dependent migration. Stimulation of Jurkat T cells with CXCL12 also resulted in ZAP-70-dependent tyrosine phosphorylation of the Src homology 2 domain-containing leukocyte protein of 76 kDa (SLP-76) adapter protein. Although CXCL12-dependent migration of SLP-76-deficient Jurkat T cells was impaired, re-expression of SLP-76 did not enhance migration. These results suggest a novel function for ZAP-70, but not SLP-76, in CXCR4 chemokine receptor signaling in human T cells.

Cell Movement↗
PubMed2001

Abnormal elution behavior of ornitine derivatized with 1-fluoro-2,4-dinitrophenyl-5-leucinamide in advanced Marfey's method.

During the course of establishing the advanced Marfey's method that has been developed to non-empirically determine the absolute configuration of constituent amino acids in a peptide using LC-MS, we encountered the "ornitine mystery" in the di-DLA (2,4-dinitrophenyl-5-leucinamide) derivative such that the elution order of ornitine (Orn) was opposite (D-->L) in spite of their relatively long retention time. In order to resolve this problem, the elution behavior of several mixed DLA and DPEA (2,4-dinitrophenyl-5-phenylethylamine) derivatives with different absolute configurations was carefully observed during HPLC. The length of the methylene chain in basic amino acids was obviously critical for this behavior, because Dab (2,4-diamino-n-butyric acid) and lysine (Lys) did not exhibit this abnormality. The presence of the carboxyamide moiety at the omega position was also essential for this phenomenon, because it was never observed in the DPEA derivatives at the omega position. Furthermore, it was found that the following combination of absolute configurations of Orn and DLA at the omega position only induced this abnormality: D-Orn and L-DLA, and L-Orn and D-DLA. This suggested that the structural interaction such as hydrogen bonding between the carboxyamide of DLA at the omega position and carboxylic acid at the alpha position in these derivatives reduced their retention power on the reversed-phase column.

Amino Acids↗
PubMed2001

C-reactive protein is an independent predictor of the rate of increase in early carotid atherosclerosis.

BACKGROUND: An elevated plasma concentration of high-sensitivity C-reactive protein (hs-CRP) is a strong predictor of cardiovascular events. However, there have been no longitudinal studies of the relations between development of atherosclerotic lesions and hs-CRP concentrations. Furthermore, it remains unknown whether increased hs-CRP concentrations result in the development of atherosclerosis. METHODS AND RESULTS: The study included 179 outpatients 40 to 79 years of age who were treated at our institute for traditional risk factors for cardiovascular disease. The patients had no evidence of advanced carotid atherosclerosis at the time of baseline examination. Patients underwent repeated ultrasonographic evaluation of the carotid arteries for 35+/-10 months. Blood samples were collected for hs-CRP measurements. Based on focal intima-media thickening >/=1.1 mm representing plaque, plaque number (PN) and plaque score (PS; the sum of all plaque thicknesses) were calculated. The development of atherosclerosis was estimated by the formula Deltavalue/year=(last value-baseline value)/number of follow-up years. Multivariate linear regression analysis revealed that the log-transformed value for hs-CRP concentration was not related to baseline PN or PS but was related to DeltaPN/year and DeltaPS/year (beta=0.29 and 0.30; P<0.001 for both) independently of the effect of traditional risk factors. CONCLUSIONS: During the early stages of carotid atherosclerosis, the hs-CRP concentration is a marker of carotid atherosclerotic activity rather than extent of atherosclerosis.

Adult↗
PubMed2001

Photoinduced group transfer radical addition of carbamotelluroates to acetylenes.

[reaction: see text] Te-Phenyl carbamotelluroates 1 add to acetylenes under irradiation of visible light to yield beta-telluroacrylamides 2 regioselectively. This reaction would be initiated by homolytic cleavage of the carbamoyl carbon-tellurium bond, producing carbamoyl and PhTe radicals. The addition reaction proceeds via a radical chain mechanism comprising two processes: (i) addition of carbamoyl radicals at the terminal carbon of the triple bond, giving vinylic radicals, and (ii) S(H)2 reaction on the Te atom caused by the attack of the vinyl radicals to 1.

Journal Article↗
PubMed2001

Rapid and simple preparation of N-linked oligosaccharides by cellulose-column chromatography.

As a means of preparing N-linked oligosaccharides from hydrazinolysates of glycoproteins in a rapid and simple manner, a method has been developed using cellulose-column chromatography. Hydrazinolysates of human IgG, containing a series of biantennary complex type oligosaccharides, were applied to a cellulose column equilibrated with (4:1:1, v/v) 1-butanol-ethanol-water. The N-linked oligosaccharides were eluted with (1:1, v/v) ethanol-water, and analyzed by HPLC in combination with sequential glycosidase digestion. The oligosaccharides, with or without sialic acid, were quantitatively recovered in the fraction eluted with (1:1, v/v) ethanol-water without UV-detectable contamination by impurities derived from protein or the cellulose. Other types of N-linked oligosaccharides of alpha1-acid glycoprotein (tetraantennary complex-type), ovalbumin (hybrid-type), and ribonuclease B (high mannose-type) were also quantitatively prepared from the hydrazinolysates by elution of the cellulose column with (1:1, v/v) ethanol-water and these had as high a quality as those prepared by conventional paper chromatography.

Animals↗