scholarly journals Physicochemical and Tissue Response of PLA Nanofiber Scaffolds Sterilized by Different Techniques

2018 ◽  
pp. 169-180
Author(s):  
Isarai Mendieta-Barrañon DDS ◽  
Osmar A. Chanes-Cuevas DDS, MSc ◽  
Marco A. Álvarez-Pérez PhD ◽  
Patricia González-Alva DDS, PhD ◽  
Luis A. Medina PhD ◽  
...  
Keyword(s):  
Tissue Regeneration ◽  
Physicochemical Characterization ◽  
Biochemical Properties ◽  
Tissue Reaction ◽  
Tissue Response ◽  
Poly Lactic Acid ◽  
Response Analysis ◽  
Sterile Product

In recent years, tissue engineering has evolved considerably, due to the problems in the biomedical area concerning tissue regeneration therapies. Currently, work has been focused on the synthesis and physicochemical characterization of poly lactic acid scaffolds, a synthetic polyester that has been extensively study for its excellent biocompatibility and biodegradability. Moreover, sterilization strategies of scaffold are a crucial step for its application in tissue regeneration, however, the sterilization process have to maintain the structural and biochemical properties of the scaffold. Therefore, it is very important to carry out studies on the sterilization methods of the sample’s material, since translational medicine is intended for in vivo applications. The aim of the present study was designed to analyze the effects of different sterilization techniques, i.e. ethylene oxide (ETO), gamma radiation (GR) and hydrogen peroxide-based plasma (H2O2) in biodegradable PLA scaffolds, and to determine the best sterilization technique to render a sterile product with minimal degradation and deformation, and good tissue response. Analysis of surface morphology showed that ETO and GR modified the PLA scaffolds without any change in its chemical composition. Moreover, the histological response showed that the scaffolds are biocompatible and those sterilized by GR showed a more severe inflammatory response, accompanied with the presence of giant foreign body cells. In conclusion, the results show that among sterilization techniques used in the preset study, the best results were observed with H2O2 sterilization, since it did not significantly modify the surface structure of the PLA fibers and their in vivo response did not cause an unfavorable tissue reaction.

Characterization of Biomaterial and Tissue Response Analysis after Implantation

2018 ◽  
Vol 930 ◽  
pp. 48-52
Author(s):  
Eliana dos Santos Câmara-Pereira ◽  
Ana Emília Holanda Rolim ◽  
Isabela Cerqueira Barreto ◽  
Laise Monteiro Campos Moraes ◽  
Lilian Campos ◽  
...  
Keyword(s):  
Repair Process ◽  
Tissue Response ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Osteogenic Potential ◽  
Response Analysis ◽  
Defect Site ◽  
Critical Defect ◽  
Defect Repair

Some biomaterials can be used to promote tissue repair process. The biological substitutes (biomaterials such as hydroxyapatite beads) can be used with some advantages and purpose of mimicking responses to on-site repair of the injured bone. The objective of this study was to evaluate the osteogenic potential of the biomaterial composed of hydroxyapatite and alginate in place of the critical defect. bioceramic samples stoichiometric hydroxyapatite was produced by the precipitation method, wet method with ion molar ratio of Ca 10 (PO 4) 6 (OH) 2, in which the Ca / P ratio was equal to 1.67. The reaction conditions were favorable to the composition of a biomaterial with crystalline phase. The synthesis of the biomaterial composed of hydroxyapatite and alginate microspheres (HAAlg5%; 200 ø 425mm) was obtained from two primary solutions with the aim of, in optimal reactive conditions, to form the precipitate. After synthesis the microspheres were implanted into the defect site. The potential effects of using HAAlg5% and the application of vibratory waves in the critical defect repair were unknown and the results described in this study are promising, considering the systemic therapy and at the site of injury. The biomaterial used promoted repair the injured tissue.

scholarly journals Tyrosinases from crustaceans form hexamers

2003 ◽  
Vol 371 (2) ◽  
pp. 515-523 ◽  
Author(s):  
Elmar JAENICKE ◽  
Heinz DECKER
Keyword(s):  
Oxygen Carrier ◽  
Spiny Lobster ◽  
Physicochemical Characterization ◽  
Primary Immune Response ◽  
Freshwater Crayfish ◽  
Astacus Leptodactylus ◽  
Purification Protocol ◽  
Palinurus Elephas

Tyrosinases, which are widely distributed among animals, plants and fungi, are involved in many biologically essential functions, including pigmentation, sclerotization, primary immune response and host defence. In the present study, we present a structural and physicochemical characterization of two new tyrosinases from the crustaceans Palinurus elephas (European spiny lobster) and Astacus leptodactylus (freshwater crayfish). In vivo, the purified crustacean tyrosinases occur as hexamers composed of one subunit type with a molecular mass of approx. 71kDa. The tyrosinase hexamers appear to be similar to the haemocyanins, based on electron microscopy. Thus a careful purification protocol was developed to discriminate clearly between tyrosinases and the closely related haemocyanins. The physicochemical properties of haemocyanins and tyrosinases are different with respect to electronegativity and hydrophobicity. The hexameric nature of arthropod tyrosinases suggests that these proteins were the ideal predecessors from which to develop the oxygen-carrier protein haemocyanin, with its allosteric and co-operative properties, later on.

scholarly journals THE SEPARATION AND CHARACTERIZATION OF SUBMICROSCOPIC COMPONENTS OF HEPATIC CYTOPLASM

1959 ◽  
Vol 7 (2) ◽  
pp. 126-132 ◽  
Author(s):  
MITURU TAKANAMI
Keyword(s):  
Alkaline Phosphatase ◽  
Principal Components ◽  
Biochemical Properties ◽  
Sedimentation Rates ◽  
Differential Centrifugation ◽  
Ultrasonic Oscillation ◽  
Ribonucleoprotein Complexes ◽  
Acid And Alkaline Phosphatase

In an ultracentrifugal study on the cytoplasmic supernatant of rabbit liver, the following two principal components were separated from the supernatant by differential centrifugation and their biochemical properties investigated: (1) a granular substance sedimented at a rate of about 250s (250s component) and (2) a few macromolecular components the sedimentation rates of which were roughly in the range of from 40s to 100s (macromolecular components). The 250s component, which was rich in lipids and easily disintegrated into smaller units by treatments of ultrasonic oscillation and of Nadesoxycholate, exhibited much higher activities of dipeptidase, acid and alkaline phosphatase than the macromolecular components. By contrast, the latter macromolecular components which belonged to ribonucleoprotein complexes exhibited comparatively high activities of RNase and esterase. Uptake in vivo of radioactive phosphate (P32) by the RNA contained in the above two principal components markedly differed from each other. When the RNA contained in the 250s component was separated by the use of Nadesoxycholate into RNA in a non-sedimentable portion and that in a sedimentable portion corresponding to a ribonucleoprotein coplex, the RNA in the latter state showed an uptake rate extremely different from that of the macromolecular components. So it is emphasized that the ribonucleoprotein complex comprised in the 250s component and that existing free in the cytoplasm (i.e. macromolecular components) are metabolically different.

Physicochemical characterization of segmented polyurethanes prepared with glutamine or ascorbic acid as chain extenders and their hydroxyapatite composites

2014 ◽  
Vol 2 (14) ◽  
pp. 1966-1976 ◽  
Author(s):  
S. M. Cetina-Diaz ◽  
L. H. Chan-Chan ◽  
R. F. Vargas-Coronado ◽  
J. M. Cervantes-Uc ◽  
P. Quintana-Owen ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Bone Tissue ◽  
Tissue Regeneration ◽  
Physicochemical Characterization ◽  
Bone Tissue Regeneration ◽  
Chain Extenders ◽  
Segmented Polyurethanes

Segmented polyurethanes with glutamine or ascorbic acid as chain extenders and their hydroxyapatite composites for bone tissue regeneration.

Influence of hydroxyapatite granule size, porosity, and crystallinity on tissue reaction in vivo . Part A: synthesis, characterization of the materials, and SEM analysis

2015 ◽  
Vol 27 (11) ◽  
pp. 1331-1338 ◽  
Author(s):  
José E. Maté Sánchez de Val ◽  
José L. Calvo-Guirado ◽  
Gerardo Gómez-Moreno ◽  
Carlos Pérez-Albacete Martínez ◽  
Patricia Mazón ◽  
...  
Keyword(s):  
Sem Analysis ◽  
Tissue Reaction ◽  
Granule Size ◽  
Hydroxyapatite Granule

scholarly journals Characterization of the Yersinia enterocolitica Type III Secretion ATPase YscN and Its Regulator, YscL

2006 ◽  
Vol 188 (10) ◽  
pp. 3525-3534 ◽  
Author(s):  
Bill Blaylock ◽  
Kelly E. Riordan ◽  
Dominique M. Missiakas ◽  
Olaf Schneewind
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Atp Hydrolysis ◽  
Biochemical Properties ◽  
Host Cells ◽  
Gram Negative Bacteria ◽  
Type Iii ◽  
Bacterial Proteins

ABSTRACT Type III secretion is a mechanism used by a broad range of gram-negative bacteria to neutralize eukaryotic defenses by enabling translocation of bacterial proteins directly into the cytoplasm of host cells. The bacterial energy source for secretion is ATP, which is consumed by an ATPase that couples ATP hydrolysis to the unfolding of secreted proteins and the dissociation of their chaperones just prior to secretion. By studying the biochemical properties of YscN and YscL of Yersinia enterocolitica, we have characterized them as the ATPase and ATPase regulator, respectively, of the type III secretion system of this organism. In vivo, YscL and YscN interact with each other, and the overexpression of glutathione S-transferase-YscL abolishes secretion and down-regulates the expression of secretion apparatus components.

scholarly journals Potential of Sustained Release Microparticles of Metformin in Veterinary Medicine: An in Vivo Pharmacokinetic Study of Metformin Microparticles as Oral Sustained Release Formulation in Rabbits.

2020 ◽  
Author(s):  
Sihem Bouriche ◽  
Angela Alonso-García ◽  
Carlos M Cárceles-Rodríguez ◽  
Farouk Rezgui ◽  
Emilio Fernández-Varón
Keyword(s):  
Veterinary Medicine ◽  
Sustained Release ◽  
Pharmacokinetic Study ◽  
Half Life ◽  
Physicochemical Characterization ◽  
Absolute Bioavailability ◽  
Poly Lactic Acid ◽  
Metformin Hydrochloride ◽  
Sustained Release Formulation

Abstract Background: Metformin hydrochloride a biguanide derivative has been widely used in the treatment of type 2 diabetes in humans. In veterinary medicine, metformin has been increasing his potential in different species as equids for insulin dysregulation, dogs and cats with diabetes. It is a highly soluble hydrophilic drug, shows incomplete absorption from the gastrointestinal tract and the absolute bioavailability is 40-60 % with a short biological half-life of 1.5-1.6 h in humans. In this study, to improve its efficacy a sustained-release microparticles of metformin was developed by loading within poly lactic acid (PLA) polymer followed by an in vivo pharmacokinetics study in rabbits. Results: Pharmacokinetic study in rabbits showed the sustained-release characteristic from the prepared microparticles with delayed time to reach maximum concentrations Tmax, decreased Cmax, increased Mean Residence Time (MRT) and half-life compared to the pure drug solution. Physicochemical characterization suggested that PLA and metformin hydrochloride interacted within the microparticles via hydrogen bonds and that the drug was transformed to an amorphous state. Conclusions: The The pharmacokinetics parameters resulted in delayed Tmax, increased MRT and t1/2, decreased Cmax of metformin from microparticles that show promise for prolonged/sustained release of metformin after oral administration in different animal species affected by insulin disorders. PLA microparticles provided sustained release of the drug, and these systems can be useful as drug carriers for hydrophilic drugs in long term disease treatment such as diabetes.

scholarly journals Anti-Inflammatory and Physicochemical Characterization of the Croton rhamnifolioides Essential Oil Inclusion Complex in β-Cyclodextrin

Biology ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 114
Author(s):  
Anita Oliveira Brito Pereira Bezerra Martins ◽  
Almir Gonçalves Wanderley ◽  
Isabel Sousa Alcântara ◽  
Lindaiane Bezerra Rodrigues ◽  
Francisco Rafael Alves Santana Cesário ◽  
...  
Keyword(s):  
Essential Oil ◽  
Vascular Permeability ◽  
Inflammatory Diseases ◽  
Physicochemical Characterization ◽  
Major Constituent ◽  
Paw Edema ◽  
Popular Medicine ◽  
Anti Inflammatory

Croton rhamnifolioides is used in popular medicine for the treatment of inflammatory diseases. The objective of this study was to characterize and evaluate the anti-inflammatory effect of C. rhamnifolioides essential oil complexed in β-cyclodextrin (COEFC). The physicochemical characterization of the complexes was performed using different physical methods. The anti-inflammatory activity was evaluated in vivo by ear edema, paw edema, cotton pellet-induced granuloma, and vascular permeability by Evans blue extravasation. The mechanism of action was validated by molecular docking of the major constituent into the cyclooxygenase-2 (COX-2 enzyme). All doses of the COEFC reduced acute paw edema induced by carrageenan and dextran, as well as vascular permeability. Our results suggest the lowest effective dose of all samples inhibited the response induced by histamine or arachidonic acid as well as the granuloma formation. The complexation process showed that the pharmacological effects were maintained, however, showing similar results using much lower doses. The results demonstrated an involvement of the inhibition of pathways dependent on eicosanoids and histamine. Complexation of β-cyclodextrin/Essential oil (β-CD/EO) may present an important tool in the study of new compounds for the development of anti-inflammatory drugs.

DELIVERY OF STIMULI-SENSITIVE NANOPARTICLES FOR VISUALIZATION OF REACTIVE OXYGEN SPECIES IN LIVER DISEASES

2021 ◽  
Vol 1 (19) ◽  
pp. 67-69
Author(s):  
P.I. Vetosheva ◽  
A.G. Shokhina ◽  
D.M. Melnik ◽  
V.V. Belousov ◽  
T.S. Zatsepin
Keyword(s):  
Reactive Oxygen Species ◽  
Physicochemical Characterization ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Leuco Form ◽  
Effective Visualization ◽  
Stimuli Sensitive

We developed lipid nanoparticles for effective visualization of reactive oxygen species (ROS) in damaged hepatocytes. These nanoparticles contain ROS - sensor: 1) HyPer – plasmid DNA encoded the same protein that is sensitive to the hydrogen peroxide or 2) hydrocyanine (leuco-form of cyanine) 5). The physicochemical characterization of the obtained particles was carried out, as well as their efficacy in vitro and in vivo was evaluated.

Sign in / Sign up

Export Citation Format

Share Document