Dynamic Influence of pH on Metalloproteinase Activity in Human Coronal and Radicular Dentin

2018 ◽  
Vol 52 (1-2) ◽  
pp. 113-118 ◽  
Author(s):  
Stella F. do Amaral ◽  
Polliana M.C. Scaffa ◽  
Renata D.S. Rodrigues ◽  
Douglas Nesadal ◽  
Marcia M. Marques ◽  
...  
Keyword(s):  
Low Ph ◽  
Buffer Solution ◽  
The Matrix ◽  
Matrix Bound ◽  
Dentin Collagen ◽  
And Control ◽  
Influence Of Ph ◽  
Incubation Buffer ◽  
Metalloproteinase Activity ◽  
Demineralized Dentin

The aim of this study was to evaluate the effect of pH on the activation of matrix metalloproteinases (MMPs) of human coronal (CD) and radicular dentin (RD). CD and RD were pulverized to powder, and proteins were extracted with 1% phosphoric acid. The extracted proteins and the demineralized powder were separately incubated in the following solutions: 4-aminophenylmercuric acetate (control) or a buffer solution at different pHs (2.5, 4.5, 5.0, 6.0, and 7.0). After incubation, proteins were separated by electrophoresis to measure MMP activities by zymography. To assess the solubilized dentin collagen, the demineralized dentin powder was sustained in incubation buffer, and the amount of hydroxyproline (HYP) released was measured. Zymography revealed MMP-2 gelatinolytic activities for CD and RD in all experimental groups. For both substrates, the lowest pH solutions (2.5, 4.5, and 5.0) yielded higher gelatinolytic activity than those obtained by the highest pH solutions (6.0 and 7.0). For HYP analysis, no detectable absorbance values were observed for pHs of 2.5 and 4.5. The amount of HYP was higher for pH 7.0 than those of all other groups (p < 0.05), except for pH 6.0. No statistical differences were found between pHs 6.0 and 5.0 and control (p > 0.05). The MMP-2 enzyme from human CD and RD is dynamically influenced by pH: at low pH, the extracted enzyme activates this latent form, whereas collagen degradation by the matrix-bound enzyme is only observed when pHs are close to neutral.

scholarly journals SYNTHESIS, MIGRATION, AND RELEASE OF PRECURSOR COLLAGEN BY ODONTOBLASTS AS VISUALIZED BY RADIOAUTOGRAPHY AFTER [3H]PROLINE ADMINISTRATION

1974 ◽  
Vol 60 (1) ◽  
pp. 92-127 ◽  
Author(s):  
Melvyn Weinstock ◽  
C. P. Leblond
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Phosphotungstic Acid ◽  
Secretory Granules ◽  
Low Ph ◽  
Collagen Fibrils ◽  
Dentin Collagen ◽  
Odontoblast Process ◽  
High Radioactivity

The elaboration of dentin collagen precursors by the odontoblasts in the incisor teeth of 30–40-g rats was investigated by electron microscopy, histochemistry, and radioautography after intravenous injection of tritium-labeled proline. At 2 min after injection, when the labeling of blood proline was high, radioactivity was restricted to the rough endoplasmic reticulum, indicating that it is the site of synthesis of the polypeptide precursors of collagen, the pro-alpha chains. At 10 min, when the labeling of blood proline had already declined, radioactivity was observed in spherical portions of Golgi saccules containing entangled threads, and, at 20 min, radioactivity appeared in cylindrical portions containing aggregates of parallel threads. The parallel threads measured 280–350 nm in length and stained with the low pH-phosphotungstic acid technique for carbohydrate and with the silver methenamine technique for aldehydes (as did extracellular collagen fibrils). The passage of label from spherical to cylindrical Golgi portions is associated with the reorganization of entangled into parallel threads, which is interpreted as the packing of procollagen molecules. Between 20 and 30 min, prosecretory and secretory granules respectively became labeled. These results indicate that the cylindrical portions of Golgi saccules transform into prosecretory and subsequently into secretory granules. Within these granules, the parallel threads, believed to be procollagen molecules, are transported to the odontoblast process. At 90 min and 4 h after injection, label was present in predentin, indicating that the labeled content of secretory granules had been released into predentin. This occurred by exocytosis as evidenced by the presence of secretory granules in fusion with the plasmalemma of the odontoblast process. It is proposed that pro-alpha chains give rise to procollagen molecules which assemble into parallel aggregates in the Golgi apparatus. Procollagen molecules are then transported within secretory granules to the odontoblast process and released by exocytosis. In predentin procollagen molecules would give rise to tropocollagen molecules, which would then polymerize into collagen fibrils.

Fluorescence imaging to assess the matrix metalloproteinase activity and its inhibitor in vivo

2008 ◽  
Vol 13 (1) ◽  
pp. 011006 ◽  
Author(s):  
Zhihong Zhang ◽  
Jie Yang ◽  
Jinling Lu ◽  
Juqiang Lin ◽  
Shaoqun Zeng ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Fluorescence Imaging ◽  
The Matrix ◽  
Metalloproteinase Activity

Delayed methylation and the matrix bound DNA methylase

1985 ◽  
Vol 126 (2) ◽  
pp. 678-684 ◽  
Author(s):  
Terence Davis ◽  
David Kirk ◽  
Angela Rinaldi ◽  
Roy H. Burdon ◽  
Roger L.P. Adams
Keyword(s):  
Dna Methylase ◽  
The Matrix ◽  
Matrix Bound

Sensing of Protein Adsorption by Composites Consisting of Silver Nanoparticles and Hydroxyapatite

2010 ◽  
Vol 76 ◽  
pp. 90-99
Author(s):  
Chikara Ohtsuki ◽  
Yuji Ichikawa ◽  
Hiroyuki Shibata ◽  
Tsukasa Torimoto ◽  
Ill Yong Kim
Keyword(s):  
Silver Nanoparticles ◽  
Protein Adsorption ◽  
Phosphate Buffer Solution ◽  
Trisodium Citrate ◽  
Localized Surface Plasmon ◽  
Surface Charges ◽  
Buffer Solution ◽  
Promising Candidate ◽  
Hydroxyapatite Powder ◽  
The Matrix

The sensing of protein adsorption by silver nanoparticles/hydroxyapatite composites was investigated using a phosphate buffer solution containing bovine serum albumin (BSA) or lysozyme (LSZ). The adsorption of BSA and LSZ on the composites prepared without using trisodium citrate was similar to plain hydroxyapatite, whereas composites prepared with trisodium citrate showed lower BSA adsorption and higher LSZ adsorption than plain hydroxyapatite powder. Because the ability of the adsorption is mainly governed by surface charges of the powders, the usage of trisodium citrate during the preparation is assumed to produce high negative charges on the surface. The protein adsorption resulted in peak shifts in localized surface plasmon resonance (LSPR) spectra. The peak shifts clearly corresponded to the concentration of the surrounding proteins up to the point of saturation of adsorption on the hydroxyapatite. The silver nanoparticles/hydroxyapatite composites are promising candidate materials for detection of protein adsorption by measurement of LSPR peak shifts, that may be attributed to changes in the dielectric properties of the matrix fluid surrounding the silver nanoparticles.

Abstract 2838: Bone Marrow Mesenchymal Stem Cells Differentiated into Beating Cardiomyocytes In Vivo and Improved Myocardial Function

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Tong Wang ◽  
Wanchun Tang ◽  
Shijie Sun ◽  
Min-shan Tsai ◽  
Max Harry Weil
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Myocardial Function ◽  
Phosphate Buffer Solution ◽  
Sprague Dawley ◽  
Buffer Solution ◽  
Marrow Mesenchymal Stem Cells ◽  
And Control

Background: In settings of heart failure, infusion of bone marrow mesenchymal stem cells (MSCs) improves myocardial function both in experimental and clinical studies. The mechanism by which MSCs improve myocardial function remains unknown. Hypothesis: MSCs may differentiate into beating myocytes in vivo. The contractility of these cells is comparable with those of myocytes. Methods: A thoracotomy was performed in 10 male Sprague-Dawley rats, weighing 350 – 450g. Myocardial infarction was induced by ligation of the left anterior descending artery (LAD). One week later, animals were randomized to receive 5×10 6 MSCs marked with PKH26 in phosphate buffer solution (PBS) or as a PBS bolus injection into local infarcted myocardium. Six weeks after the MSCs or PBS injection, the hearts were harvested and digested with collagease type II and single cardiomyocytes were obtained. PKH26 labeled myocytes differentiating from MSCs were observed with a microscope Olympus I×71. The contractility of labeled and unlabeled beating cells in MSCs-treated animals was compared. The contractility of unlabeled myocytes was compared between MSCs-treated and control groups. Result: The beating fluorescent labeled myocytes can be found in MSCs-treated animals [(1.2±0.4) ×10 6 ] and contractility of these cells were the same as that of unlabeled beating myocytes (Table 1 ). The contractility of unlabeled myocytes, however, was significantly better in MSCs-treated animals. Conclusion: MSCs could differentiate into the beating myocytes. However, this may not be the sole mechanism of improved myocardial function. Table 1 Cells contractility (%)

Automated System of Stabilization and Position Control of Aviation Equipment

2019 ◽  
pp. 297-330
Author(s):  
Olha Sushchenko
Keyword(s):  
Position Control ◽  
Transfer Functions ◽  
Controller Design ◽  
Robust Stabilization ◽  
Automated System ◽  
Simulink Model ◽  
The Matrix ◽  
Stabilized Platform ◽  
And Control ◽  
The Mathematical Model

In this chapter, the author presents the problems of design of the robust automated system for stabilization and control of platforms with aircraft observation equipment. The mathematical model of the triaxial stabilized platform is developed. The procedure of synthesis of robust stabilization system based on robust structural synthesis is represented. The above-mentioned procedure uses loop-shaping approach and method of the mixed sensitivity. The matrix weighting transfer functions are obtained. The optimization programs in MatLab are developed. The developed procedures are approved based on the results of simulation by means of the appropriate Simulink model. The obtained results can be useful for unmanned aerial vehicles and aircraft of special aviation, which are used for monitoring technical objects and aerial photography. The technical contributions are procedures of the robust controller design represented as the flowchart. The proposed approach is validated by application of the theoretical suppositions to the concrete example and appropriate simulation results.

scholarly journals 169 CULTURE OF MURINE EMBRYONIC STEM CELLS ON NWPF DISCS

2005 ◽  
Vol 17 (2) ◽  
pp. 235 ◽  
Author(s):  
G. Cetinkaya ◽  
S. Arat ◽  
H. Odaman Mercan ◽  
M.A. Onur ◽  
A. Tumer
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Es Cells ◽  
Three Dimensional ◽  
Embryonic Stem ◽  
Signalling Pathways ◽  
Feeder Layers ◽  
The Matrix ◽  
Matrix Bound

Murine embryonic stem cells derived from the inner cell mass of mouse blastocysts can be maintained in culture for extended periods by using feeder layers and leukemia inhibitory factor (LIF). Maintenance of undifferentiated status occurs via LIF-mediated signalling pathways. In this study we cultured embryonic stem (ES) cells in Knockout-DMEM with serum replacement on a three-dimensional matrix, non-woven polyester fabric (NWPF), which is formed from non-arrayed polyethylene teraphthalate fibers. The surface of the fibers was modified by immobilizing LIF. While stimulating the matrix-bound form of LIF in vitro, we also tried to induce LIF-mediated signalling pathways continually. Our goal was to constitute a synthetic microenvironment that would support the undifferentiated growth of murine ES cells. Experimental groups were examined according to colony morphology, alkaline phosphatase activity, SSEA-1 antibody immunoreactivity, and SEM analyses. It was shown that three dimensional macroporous fibrous matrix, NWPF could support growth of undifferentiated ES cells. However, the ratio of undifferentiated colonies was higher on feeder layers than an polymeric surfaces (93% on mouse embryonic fibroblasts; 63,7% on hydrolized polymeric surface, P < 0,05). Results showed that LIF-immobilized surfaces supported undifferentiated growth of ES cells better than hydrolyzed surfaces. Colonies cultured on LIF-immobilized surfaces, had higher alkaline phosphatase activity and undifferentiated phenotype ratio than those on hydrolyzed surfaces. When the soluble or the matrix-bound form of LIF was used, the number of undifferentiated colonies increased in the polymeric groups (77.8% soluble LIF; 81.6% matrix bound LIF P < 0,05). On NWPF discs, ES cells formed big cell aggregates which had high alkaline phosphatase activity but low SSEA-1 immunoreactivity . When they were passaged to feeder layers, SSEA-1 activity increased. We managed to obtain undifferentiated colonies on NWPF discs by using LIF but the skeletal structure of polymeric matrix would be more convenient for differentiation studies. This study was performed in TUBITAK-RIGEB and supported by a part of grant from Hacettepe University (0102601001).

scholarly journals Calcium-dependent opening of a non-specific pore in the mitochondrial inner membrane is inhibited at pH values below 7. Implications for the protective effect of low pH against chemical and hypoxic cell damage

1991 ◽  
Vol 278 (3) ◽  
pp. 715-719 ◽  
Author(s):  
A P Halestrap
Keyword(s):  
Protective Effect ◽  
Adenine Nucleotide ◽  
Cell Damage ◽  
Liver Mitochondria ◽  
Low Ph ◽  
Hypoxic Cell ◽  
Inner Membrane ◽  
Calcium Dependent ◽  
Mitochondrial Inner Membrane ◽  
The Matrix

1. The rate of opening of the Ca(2+)-induced non-specific, cyclosporin A-inhibited, pore of the mitochondrial inner membrane of rat heart and liver mitochondria at pH 6.0 was less than 10% of that at pH 7.4. 2. The effect could not be explained by inhibition of Ca2+ uptake into the mitochondria, or of the matrix peptidyl-prolyl cis-trans isomerase (PPIase), or of the Ca(2+)-induced conformational change of the adenine nucleotide translocase. 3. It is suggested that the proposed interaction of matrix PPIase with the ‘c’ conformation of the adenine nucleotide carrier in the presence of Ca2+ [Griffiths & Halestrap (1991) Biochem. J. 274, 611-614] is inhibited by low pH. 4. The relevance of this to the protective effect of low pH on hypoxic and chemical-induced cell damage is discussed.

scholarly journals Living in the matrix: assembly and control of Vibrio cholerae biofilms

2015 ◽  
Vol 13 (5) ◽  
pp. 255-268 ◽  
Author(s):  
Jennifer K. Teschler ◽  
David Zamorano-Sánchez ◽  
Andrew S. Utada ◽  
Christopher J. A. Warner ◽  
Gerard C. L. Wong ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Matrix Assembly ◽  
The Matrix ◽  
And Control

Spent Fuel Corrosion Behavior in Salt Solution in the Presence of Hydrogen Overpressure

2001 ◽  
Author(s):  
Andreas Loida ◽  
Bernd Grambow ◽  
Horst Geckeis
Keyword(s):  
Gas Phase ◽  
Spent Fuel ◽  
Nacl Solution ◽  
Release Rates ◽  
Corrosion Rates ◽  
The Matrix ◽  
Matrix Bound ◽  
Safety Assessments ◽  
Container Material

Abstract The simultaneous corrosion of spent fuel and Fe-based container material is characterized by the formation of large amounts of hydrogen, which control the composition of the gas phase. Various experimental data indicate that the matrix dissolution rate and the release rates of important radionuclides decrease, if the H2 overpressure increases. To quantify to what extent the hydrogen overpressure may counteract radiolysis enhanced matrix dissolution rates, and to take credit from the effect of hydrogen overpressure in long-term safety assessments of the repository, a detailed experimental investigation has been initiated. High burnup spent fuel is being corroded under anoxic conditions in the absence of carbonate in 5m NaCl solution under an external H2 overpressure of 3.3 bar. This pressure is in the same range as observed in a long-term test using spent fuel and Fe-powder. Results obtained after 117 days of testing show that due to constant or decreasing concentrations of Sr and other matrix bound radionuclides, corrosion rates were not measurable indicating a stop of matrix dissolution or very low long-term rates. Grain boundary release of Cs and fission gases was found to continue under hydrogen overpressure. Compared to tests in the absence of hydrogen solution concentrations decreased by about ca. 1.5 orders of magnitude for U (10−8 M), Am, Eu (10−10 M), whereas the decrease of Np (3×10−10 M), Tc (5×10−9 M) and Pu (4×10−9 M) concentrations was found to be less significant.

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