PREPARATION OF SPHERICAL GRANULES OF OCTACALCIUM PHOSPHATE FOR MEDICAL APPLICATION

2012 ◽  
Vol 05 (02) ◽  
pp. 1260009 ◽  
Author(s):  
NATSUKO ITO ◽  
MASANOBU KAMITAKAHARA ◽  
KOJI IOKU
Keyword(s):  
Single Phase ◽  
Treatment Time ◽  
Medical Application ◽  
Octacalcium Phosphate ◽  
Gelatin Solution ◽  
Shearing Force ◽  
Buffer Solution ◽  
Defect Site ◽  
Human Bones ◽  
Acetic Acid Buffer

Octacalcium phosphate (OCP) is regarded as a precursor of hydroxyapatite (HA) which is an inorganic constituent of human bones and teeth. OCP is also becoming regarded as one of the important biomaterials. Despite some studies on OCP as biomedical materials, there are few methods for shape forming of OCP. The objective of this study is preparing spherical granules of OCP. The spherical granular shape has an advantage for handling. The spherical granules can achieve easy injection into the defect site by a catheter. In the present study, preparation of spherical granules of OCP from α-tricalcium phosphate (α-TCP) was attempted. The starting material of α-TCP powder was dispersed in the gelatin solution. The resultant slurry was added into vegetable oil, and then the spherical granules of α-TCP/gelatin were formed by the surface tension of the slurry and the shearing force of stirring. By calcining the obtained α-TCP/gelatin granules, the spherical granules with α-TCP single phase were obtained. These spherical granules of α-TCP were immersed in the acetic acid buffer solution whose temperature and pH were controlled. The calcium phosphate spherical granules containing OCP were obtained. The shorter treatment time was favorable for preparing spherical granules containing more OCP.

In situ digestion of barley chromosomes with restriction endonucleases

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 793-798 ◽  
Author(s):  
Y. Kamisugi ◽  
Y. Ikeda ◽  
M. Ohno ◽  
M. Minezawa ◽  
K. Fukui
Keyword(s):  
Hordeum Vulgare ◽  
Restriction Endonuclease ◽  
Treatment Time ◽  
Band Pattern ◽  
Restriction Endonucleases ◽  
Chromosome Band ◽  
Buffer Solution ◽  
Hordeum Vulgare L

In situ digestion of barley chromosomes with restriction endonucleases was examined. All the treatments with five restriction endonucleases, MboII, RsaI, HaeIII, HinfI, and DraII, showed various band patterns on the barley chromosomes. Differences were observed in the band patterns produced with different restriction endonucleases. Uneven staining patterns, similar to the band patterns by the endonuclease treatments, also appeared when the chromosomes were treated with the buffer solution without the enzyme. The band patterns observed both with and without the endonucleases were classified into the four types and the frequency of each type among the different treatments was investigated. The change of the band types along with treatment time was accelerated by the addition of the restriction endonuclease. As a result, it was concluded that there existed chromosome band patterns that were specific to the endonuclease treatments and that the buffer solution also affected to the production of the bands on the chromosomes.Key words: Hordeum vulgare L., chromosome band pattern, in situ digestion, restriction endonuclease, restriction banding.

scholarly journals STUDY OF THE BEHAVIOURS OF SINGLE-PHASE TURBULENT FLOW AT LOW TO MODERATE REYNOLDS NUMBERS THROUGH A VERTICAL PIPE. PART I: 2D COUNTERS ANALYSIS

2020 ◽  
pp. 108-122
Author(s):  
Akeel M. Ali Morad ◽  
Rafi M. Qasim ◽  
Amjed Ahmed Ali
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Single Phase ◽  
Static Pressure ◽  
Fluid Velocity ◽  
Mixing Length ◽  
Shearing Force ◽  
Vertical Pipe ◽  
Moderate Reynolds Number

This study presents a model to investigate the behavior of the single-phase turbulent flow at low to moderate Reynolds number of water through the vertical pipe through (2D) contour analysis. The model constructed based on governing equations of an incompressible Reynolds Average Navier-Stokes (RANS) model with (k-ε) method to observe the parametric determinations such as velocity profile, static pressure profile, turbulent kinetic energy consumption, and turbulence shear wall flows. The water is used with three velocities values obtained of (0.087, 0.105, and 0.123 m/s) to represent turbulent flow under low to moderate Reynolds number of the pipe geometry of (1 m) length with a (50.8 mm) inner diameter. The water motion behavior inside the pipe shows by using [COMSOL Multiphysics 5.4 and FLUENT 16.1] Software. It is concluded that the single-phase laminar flow of a low velocity, but obtained a higher shearing force; while the turbulent flow of higher fluid velocity but obtained the rate of dissipation of shearing force is lower than that for laminar flow. The entrance mixing length is affected directly with pattern of fluid flow. At any increasing in fluid velocity, the entrance mixing length is increase too, due to of fluid kinetic viscosity changes. The results presented the trends of parametric determinations variation through the (2D) counters analysis of the numerical model. When fluid velocity increased, the shearing force affected directly on the layer near-wall pipe. This leads to static pressure decreases with an increase in fluid velocities. While the momentum changed could be played interaction rules between the fluid layers near the wall pipe with inner pipe wall. Finally, the agreement between present results with the previous study of [1] is satisfied with the trend

Effect of pH Values on Conversion of Calcite Crystals into Calcium Phosphate Phases in Buffer Solutions

2007 ◽  
Vol 353-358 ◽  
pp. 2183-2186 ◽  
Author(s):  
Ya Ping Guo ◽  
Bao Qiang Li ◽  
Yu Zhou ◽  
De Chang Jia
Keyword(s):  
Calcium Phosphate ◽  
Ph Value ◽  
Octacalcium Phosphate ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
Effect Of Ph ◽  
X Ray ◽  
Buffer Solutions ◽  
Ph Values

Calcium phosphate phases with laminar-plate structure were converted from calcite powders after soaking in phosphate buffer solutions of pH’s 6.0-8.0 at 37 °C for 9 days. The effect of pH values on the conversion of calcite crystals was investigated by X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy. If the pH value of a buffer solution is kept at 6.0, calcite powders are converted mainly to dicalcium phosphate dehydrate (DCPD) or octacalcium phosphate (OCP). If the pH value is kept at 6.4 or 7.0, calcite powders are converted mainly to OCP. Hydroxyapatite (HAP) with poorly crystalline can be obtained from calcite powders both by treatment of a basic buffer solution, and by treatment of an acid buffer solution without regulating its pH value during the reaction. The conversion mechanism of calcite crystals is a dissolution-precipitation reaction.

scholarly journals BISTABILITY AND CYTOTOXICITY OF MEDICAL DEVICES BASED ON CROSS-LINKED BIOPOLYMERS

2018 ◽  
Vol 20 (1) ◽  
pp. 79-85
Author(s):  
E. A. Nemets ◽  
A. P. Pankina ◽  
V. A. Surguchenko ◽  
V. I. Sevastianov
Keyword(s):  
Treatment Time ◽  
Weight Ratio ◽  
Farm Animals ◽  
Cross Linking ◽  
Residual Pressure ◽  
Buffer Solution ◽  
Simple Method ◽  
Constant Weight ◽  
Medical Products ◽  
High Level

The increase in biostability of medical products/materials based on proteins and their derivatives, including resorbable 2Dand 3D-matrices for tissue engineering and regenerative medicine is usually achieved by means of cross-linking with glutaraldehyde (GA). One of the serious fl aws of the products stabilized with GA is their cytotoxicity caused by trace amounts of GA which are diffi cult to remove from cross-linked biopolymer matrices, thus the search for chemical and physical methods of cross-linking of such medical products remains essential. Aim:to compare the infl uence of various cross-linking methods on the cytotoxicity of collagen and gelatin samples.Materials and methods.Samples – fi lms with diameter of 30 mm and thickness of ~ 150 μm, – were obtained by irrigation method usingthesolution of scleral collagen (SC) of Type farm animals or with gelatin with the subsequent drying at 37º С until constant weight on air. Samples of porous matrices in shape of tubes of gelatin and polyoxybutirate-co-valerate with the weight ratio 2:1 were obtained by electrospinning. The cytotoxicity of structurally stabilized samples was studied by fi ve methods: 1) dehydrothermal cross-linking with the residual pressure of 10–20 mm Hg and temperature of 120 °С; 2) injection of GA immediately into the biopolymer solution; 3) with GA vapors; 4) with GA vapors with the subsequent incubation in phosphate buffered saline (PBS) with рН = 7.4; 37 °С; 24 h; 5) with GA vapors with the subsequent incubation in 0.1% lysine solution with рН = 7.4; 37 °С; 24 hour in DMEM medium. Cytotoxicity of samples was evaluated according to the requirements of interstate standard GOST ISO 10993-5-2011 on the culture of mice fi broblasts of NIH 3Т3 line using extracts from samples (37 °С; 24 h) and by means of direct contact of samples with these cells.Results.Matrices treated hydrothermally demonstrated complete absence of cytotoxicity. Samples, fi xated in GA solution in the range of concentrations from 0.01 to 1.0% demonstrated a high level of cytotoxicity which does not answer the requirements of GOST ISO 10993-5-2011. Fixation of collagen and gelatin matrices with GA vapors during 48 h infl uences their cytotoxicity minimally but with the treatment time increased to 72 hours cytotoxicity escalates to severe levels. With the subsequent incubation of cytotoxic gelatin samples in PBS the decrease in cytotoxicity to the levels corresponding with the requirements of GOST ISO 10993-5-2011 was observed. For the analogous decrease in cytotoxicity of collagen fi lms treated with GA vapors during more than 48 h an additional incubation in lysine solution was needed.Conclusion.Dehydrothermal cross-linking method is optimal from the view point of absence of cytotoxicity of stabilized biopolymers, however its area of application is limited by the risk of infl uence of high temperatures on the medico-technical properties of the products. Fixation in GA vapors is a universally applicable and a rather simple method of treatment of medical products or biopolymer-based coatings, but it does not resolve the issue of their cytotoxicity at treatment times exceeding 48 h. Rinsing in buffer solution in case of gelatin or treatment with the amino acid (lysine) solution in case of collagen allow to decrease the level of cytotoxicity of products stabilized with GA vapors to the values corresponding with the requirements of GOST ISO 10993-5-2011.

Development of Bisphosphonate-Calcium Phosphate Composites and Drug Release Characteristic

2012 ◽  
Vol 1418 ◽  
Author(s):  
Hidekuni Kameda ◽  
Tomohiko Yoshioka ◽  
Toshiyuki Ikoma ◽  
Junzo Tanaka
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Drug Carrier ◽  
Phosphate Buffer Solution ◽  
Octacalcium Phosphate ◽  
Acetate Buffer Solution ◽  
Unit Weight ◽  
Unit Surface Area ◽  
Acetate Solution ◽  
Buffer Solution

ABSTRACTBisphosphonate (Bp) was adsorbed on the surface of crystalline calcium phosphates (CP); hydroxyapatite (HAp), octacalcium phosphate (OCP) and Dicalcium phosphate dehydrate (DCPD). The amount of Bp adsorbed was the largest for DCPD per unit surface area, while the amount was the largest for HAp per unit weight. The composites of Bp and amorphous calcium phosphate (ACP) were synthesized by titrating calcium acetate solution into phosphate buffer solution containing Bp. The amount of Bp doped in the composites was 366 μg / mg and was approximately 7 times larger than those of Bp adsorbed on the crystalline Calcium phosphates. TG-DTA measurements of a Bp-calcium and the composite indicated exothermic peaks due to Bp combustion, of which temperature were shifted to higher temperature for the composite. Bp in the composites was gradually released into phosphate buffered saline, while Bp was rapidly released into acetate buffer solution accompanied with the dissolution of ACP. This result suggests that the composite of Bp and ACP has potential for a drug-carrier releasing Bp in response to the condition of osteoclastic bone resorption.

Column-Chromatographic Analysis of Naturally Fluorescing Compounds: III. Rapid Analysis of Serotonin and Tryptamine

1974 ◽  
Vol 20 (4) ◽  
pp. 421-423 ◽  
Author(s):  
D D Chilcote
Keyword(s):  
Ammonium Acetate ◽  
Exchange Resin ◽  
Detection System ◽  
Cation Exchange Resin ◽  
Rapid Analysis ◽  
Buffer Solution ◽  
Column Temperature ◽  
Strong Cation Exchange ◽  
Acetic Acid Buffer

Abstract A previously described [Clin. Chem. 18, 778 (1972)] chromatographic separation and fluorimetric detection system has been adapted to the determination of serotonin and tryptamine. A strong cation-exchange resin, "Aminex A-6," is used. At a column temperature of 60 °C, serotonin and tryptamine are eluted in 0.5 and 1.0 h, respectively, with an ammonium acetate-acetic acid buffer solution (6 mol of acetate per liter). The sensitivity of the detector allows reliable quantitation of 100 ng of each amine in the sample loaded onto the column.

scholarly journals Radiation Crosslinked Smart Peptide Nanoparticles: A New Platform for Tumor Imaging

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 714
Author(s):  
Atsushi Kimura ◽  
Miho Ueno ◽  
Tadashi Arai ◽  
Kotaro Oyama ◽  
Mitsumasa Taguchi
Keyword(s):  
Surface Potential ◽  
Tumor Targeting ◽  
Tumor Imaging ◽  
Drug Carriers ◽  
Medical Application ◽  
Fluorescent Labeling ◽  
Amino Acid Residues ◽  
Buffer Solution ◽  
Peptide Nanoparticles ◽  
Tumor Accumulation

Nanoparticles have been employed to develop nanosensors and drug carriers that accumulate in tumors. Thus, it is necessary to control the particle size, surface potential, and biodegradability of these nanoparticles for effective tumor accumulation and safe medical application. In this study, to form a nanoparticle platform suitable for diagnostic and drug delivery system (DDS) applications, peptides composed of aromatic amino acid residues were designed and synthesized based on the radiation crosslinking mechanism of proteins. The peptide nanoparticles, which were produced by γ-ray irradiation, displayed a positive surface potential, maintained biodegradability, and were stable in water and phosphoric buffer solution during actual diagnosis. The surface potential of the peptide nanoparticles could be changed to negative by using a fluorescent labeling reagent, so that the fluorescent-labeled peptide nanoparticles were uptaken by HeLa cells. The radiation-crosslinked nanoparticles can be applied as a platform for tumor-targeting diagnostics and DDS therapy.

Determining the Critical Crevice Depth for Iron in a Sodium Acetate-Acetic Acid Buffer Solution

2003 ◽  
Vol 150 (9) ◽  
pp. B445 ◽  
Author(s):  
Marc Vankeerberghen ◽  
Mohammed Abdulsalam ◽  
Howard Pickering ◽  
Johan Deconinck
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate ◽  
Buffer Solution ◽  
Acid Buffer ◽  
Acetic Acid Buffer

Observation of Transformation Behavior of Octacalcium Phosphate to Hydroxyapatite

2012 ◽  
Vol 529-530 ◽  
pp. 11-14
Author(s):  
Natsuko Ito ◽  
Masanobu Kamitakahara ◽  
Koji Ioku
Keyword(s):  
Bone Formation ◽  
Heterogeneous Nucleation ◽  
Temporal Change ◽  
Octacalcium Phosphate ◽  
The Body ◽  
Distilled Water ◽  
Transformation Behavior ◽  
Transformation Mechanism ◽  
Human Bones ◽  
Apatitic Phase

Octacalcium phosphate (OCP) is regarded as a precursor of hydroxyapatite (HA) which is a main inorganic comstituent of human bones and teeth. OCP is becoming regarded as an important biomaterial. Recently, implanted OCP was found to be converted to apatitic phase in the body and support bone regeneration. Therefore, it is important to reveal the transformation mechanism of OCP to HA for revealing the mechanism of bone formation and for the development of biomedical materials for bone. In this study, we focused on the dissolution of OCP and precipitation of HA. OCP particles were immersed in distilled water at 60 °C. The temporal change of the immersed powders and immersing solution were examined, and the transformation mechanism of OCP to HA was discussed. As there was an unreactive period in the first stage of the transformation, HA crystals seemed to grow easily once HA nuclei were formed. It is speculated that HA nuclei formed on OCP crystals by heterogeneous nucleation, and then HA crystals grow using calcium and phosphoric ions supplied from dissolved OCP.

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