Addition Of HA Research Articles

Sodium Hyaluronate Supplemented Culture Media as a New hMSC Chondrogenic Differentiation Media-Model for in vitro/ex vivo Screening of Potential Cartilage Repair Therapies.

Surgical strategies to treat articular cartilage injury such as microfracture, expose human bone marrow stem cells (hMSCs) to synovial fluid and its components. High molecular weight hyaluronan (hMwt HA) is one of the most abundant bioactive macromolecules of healthy synovial fluid (hSF) and it plays an important role in the protection of opposing articular cartilage surfaces within the synovial joint. Although hMwt HA has been extensively used to attempt the engineering of the cartilage tissue, its effect as media supplement has not been established. Indeed, current media are often simple in their composition and doesn’t recapitulate the rheological and biological features of hSF. In addition, critical in vivo molecules that can potentially change the chondrogenic behavior of hBMSCs to make the in vitro results more predictive of the real in vivo outcome, are lacking. In order to be one step closer to the in vivo physiology of hSF, a new culture media supplemented with physiological level of hMwt HA was developed and the effect of the hMwt HA on the chondrogenesis of hMSCs that would be present in a traumatic defect after marrow stimulation techniques, was investigated. hBMSC-seeded fibrin-polyurethane constructs were cultured in a serum free chondropermissive control medium (HA- TGFβ-). This medium was further supplemented with 10 ng/mL TGFβ1 (HA- TGFβ+) or 2 mg/ml hMwt HA 1.8 MDa (HA+ TGFβ-) or both (HA+ TGFβ+). Alternatively, 1 MDa HA was mixed with the fibrin at 0.2 mg/ml (HASc TGFβ+). The effect of hMwt HA on hMSC differentiation was investigated at the gene expression level by RT-qPCR and total DNA, sulfated glycosaminoglycans and Safranin O staining were evaluated. Addition of hMwt HA to the culture media, significantly increased the synthesis of sulfated glycosaminoglycans, especially in the early days of chondrogenesis, and reduced the upregulation of the hypertrophic cartilage marker collagen X. hMwt HA added inside the fibrin gel(HASc TGF+) led to the best matrix deposition. hMwt HA can be one key medium component in a more reliable in vitro/ex vivo system to reduce in vitro artifacts, enable more accurate pre-screening of potential cartilage repair therapies and reduce the need for animal studies.

Facile fabrication of boronized Ti6Al4V/HA composites for load-bearing applications

The boronized Ti6Al4V/hydroxyapatite (HA) composites were fabricated by facile microwave sintering of mixed powders of Ti6Al4V, HA and TiB2 at 1050 °C for 30 min, with a focus on the effects of HA addition (0–10 wt%) on the mechanical properties of the resulting composites for loading-bearing biomedical applications. Due to phase and microstructural evolutions, there were two stages of the variations of mechanical properties. In stage I with addition of less than 5 wt% HA, there existed only modest decreases of the properties contributed by the “lens effect” of microwave and the “buffer effect” of TiB. In stage II with higher HA addition, the properties of the composite declined rapidly mainly due to more and unevenly distributed pores with poorer densification of the matrix. The composite synthesized with addition of 5 wt% HA exhibited the optimal and superior mechanical properties compared with other types of related composites and natural bones.

In-vitro bio-corrosion behavior of friction stir additively manufactured AZ31B magnesium alloy-hydroxyapatite composites.

Magnesium and its alloys have been considered for consumable bio-implant applications due to their similar mechanical properties to the natural bone and biodegradability. Nevertheless, uncontrollable corrosion rate and limited bioactivity of Mg based materials in biological environment restrain their application. In light of this, objective of the present study was to explore addition of hydroxyapatite (HA, Ca10(PO4)6OH2), a ceramic similar to bone mineral, into AZ31B Mg alloy and its effects on bio-corrosion behavior. Friction stir processing based additive manufacturing route was employed for producing AZ31B Mg-HA composites. Various HA contents (5, 10, and 20wt%) were incorporated into Mg matrix. The microstructural observation revealed that the size of α-Mg grains reduced significantly after friction stir process. HA incorporation took place at micro/nanoscale in α-Mg matrix under the thermo-mechanical forces exerted by friction stir process. The corrosion behavior of friction stir processed Mg-HA composites was investigated using electrochemical methods in simulated body fluid. The results indicated an improvement in corrosion resistance for the composites compared to untreated AZ31B which was attributed to significant grain refinement upon friction stir process. On the other hand, incremental addition of HA had an opposing effect due to localized micro/nano-galvanic couples. As a result, friction stir process Mg-5wt% HA composite demonstrated the highest corrosion resistance due to an optimum balance between beneficial effects of grain size refinement and limited number of local galvanic couples compared to the other friction stir process samples explored in the present work.

Micromorphology, mechanical, crystallization and permeability properties analysis of HA/PBAT/PLA (HA, hydroxyapatite; PBAT, poly(butylene adipate‐co‐butylene terephthalate); PLA, polylactide) degradability packaging films

AbstractIn this study, the self‐made nano‐hydroxyapatite (HA) and poly(butylene adipate‐co‐butylene terephthalate) copolyesters (PBAT) were used as fillers, and composite films of HA/PLA (PLA, polylactide) and HA/PBAT/PLA systems were prepared. The micromorphology, mechanical properties, thermal properties, crystallinity, water vapor permeability and oxygen permeability of the composite films were studied. The results show that the self‐made HA has a porous rod‐like structure with a size of 30–50 nm. PBAT was dispersed uniformly in the HA/PLA matrix in the form of spherical particles and formed many pores and holes. The tensile strength, elongation at break and modulus of elasticity of HA/PLA composite films were increased by adding 10 wt% PBAT. The addition of HA and PBAT played a synergistic function in improving the crystallinity of the composite films. The water vapor and oxygen permeabilities of HA/PLA and HA/10%PBAT/PLA composite films can be regulated by adjusting the amount of HA. The results of this study indicate that composite films with higher water vapor and oxygen permeabilities exhibit great potential for applications in green packaging and fresh‐keeping packaging. © 2019 Society of Chemical Industry

Synthesis of biomedical Ti-25Ni-15Si-10HA alloy by mechanical alloying and spark plasma sintering

In this research approach, a β-phase titanium alloy was produced successfully employing mechanical alloying and consolidated with spark plasma sintering (SPS) process. Herein, Ni, Si and HA powders with varied weight percentage were used to fabricate the Ti alloy. The influence of HA addition on microstructure of the alloy was assessed using optical microscopy route and further amplified using field emission scanning electron microscopy (FESEM). The elemental composition and phase of Ti-alloy was investigated using x-ray diffractometer. Vicker hardness (HV) tester was employed to estimate the micro hardness of the specimen surface. During the FESEM analysis, it was observed that within the sintering process, alloy exhibits complex reactions with HA, which leads to the progress of bioactive compounds (CaO, TiO2, Ca3 (PO4)2, Ti2Ni, CaTiO3 and CaTiSiO5) enhancing the bioactivity of the Ti alloy. The fabricated Ti alloy (Ti-25Ni-15Si-10HA) exhibited superior microhardness (∼458HV) at 900°C, comparative to the other alloys of the native category. Based upon the current investigation, Ti-25Ni-15Si-10HA alloy could find applications as bioimplants in dental and orthopedic areas.

Comment on “Arsenite biotransformation by Rhodococcus sp.: Characterization, optimization using response surface methodology and mechanistic studies”, Science of the Total Environment, 687, 577–589(2019)

Kumari et al. investigated the arsenic resistance and arsenic biotransforming ability in three bacterial species, mainly Rhodococcus sp.. But in the use of response surface methodology to optimize key parameters that affect the removal of arsenic, the effects of dissolved oxygen and the effect of HA addition on the adsorption or oxidation of arsenic by bacteria were ignored. We therefore recommend taking the impacts of the above-mentioned factors on the removal of arsenic into examination.

ACTR-50. PRESERVATION OF NEUROCOGNITIVE FUNCTION & PATIENT-REPORTED SYMPTOMS WITH HIPPOCAMPAL AVOIDANCE (HA) DURING WHOLE-BRAIN RADIOTHERAPY (WBRT) FOR BRAIN METASTASES: LONG-TERM RESULTS OF NRG ONCOLOGY CC001

Abstract BACKGROUND NRG-CC001 sought to evaluate the neuro-protective effects of avoiding the peri-hippocampal stem cell niche using intensity-modulated radiotherapy during WBRT. METHODS Patients with brain metastasis were stratified by RPA class and prior radiosurgery/surgery and randomized to WBRT+M or HA-WBRT+ Memantine (M) (30Gy in 10 fractions). Standardized NCF tests and the M.D. Anderson Symptom Inventory Brain Tumor (MDASI-BT) were obtained at baseline, 2, 4, 6, and 12 months (mos). The primary endpoint was NCF failure defined using the reliable change index. Pre-specified secondary endpoints included patient-reported symptoms using the MDASI-BT. Time to NCF was reported as cumulative incidence (with death without NCF failure as a competing risk); between-arms differences were tested using Gray’s test. Deterioration at discrete time-points were tested using chi-square tests. MDASI-BT symptom burden, interference, and cognitive and neurologic burden were analyzed using mixed effects models and t-tests within the model using Hochberg’s multiplicity adjustment. RESULTS A total of 518 patients were randomized from 7/2016 to 3/2018. Median follow-up for alive patients was 12.1 mos, with no difference between arms in terms of toxicity, overall survival or intracranial progression-free survival. HA-WBRT+M was associated with lower risk of NCF failure (adjusted HR=0.739, 95% CI: 0.577–0.945, p=0.0.016), with differences first noted at 4 mos in Trail Making Test Part-B (23.3% vs. 40.4% deteriorated, p=0.012). Age did not dilute treatment effect. HA-WBRT+M was associated with reduced cognitive symptom burden in an imputed model (estimate=-0.29, p=0.0425), and also reduced overall symptom burden (p< 0.0001) and interference (p< 0.0016) at 6 mos. CONCLUSIONS The addition of HA to WBRT+M preserved NCF and reduced patient reported cognitive symptom burden, overall symptom burden and symptom interference and should be considered standard of care for any patient fit enough to have WBRT. Supported by grants UG1CA189867 (NCORP), U10CA180868 (NRG Oncology Operations), DCP from the National Cancer Institute.

Chain conformation: A key parameter driving clustering or dispersion in polyelectrolyte – Colloid systems

The work presents the characterization of Pluronic F127 micellar solutions in presence of hyaluronic acid in semi-dilute regime. The effects of the nature and salt concentration are investigated by differential scanning calorimetry and small angle neutron scattering. Hyaluronic acid reduces the critical micellar temperature to the same extend as an increase of the ionic strength. Within the investigated HA concentration range, the size and shape of the micelles are not modified by the addition of HA but their dispersion state depends on the salt concentration. By increasing the ionic strength we observe the formation of small micellar clusters which organize into a face-centered cubic liquid crystalline phase at high salt concentration. This behavior is reinforced by increasing the HA concentration or molecular weight. The nature of the salt plays also a role and divalent cations such as Ca2+ promote the clustering of micelles and their crystallization. The origin of the aggregative behavior is the change of the HA chain conformation –from stretched to coil- by addition of salt which in turn induces an excluded volume around the micelles and exerts a depletion interaction.

Fabrication of gelatin/hydroxyapatite/3D-graphene scaffolds by a hydrogel 3D-printing method

In this study, we demonstrate the fabrication of three-dimensional reduced graphene oxide/hydroxyapatite (HA)/Gelatin scaffolds by employing two steps, including a hydrothermal autoclave with hydrogen gas injection to synthesize three-dimensional graphene (3DG)/HA powders and a hydrogel 3D-printing method to fabricate the scaffolds. Evaluations were performed separately for synthesized powders and fabricated scaffolds, which included field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, Raman spectroscopy, and instrumented compression experiments. The powders characterization results showed that the nanostructured hybrid powders were successfully synthesized. The graphene sheets were stacked in 3D and the HA nanorods were attached on the surface of the graphene. Interface analysis showed that the two phases (HA/Graphene) are connected coherently and various preferential directions played a role in the growth of hydroxyapatite crystals. Characterization of the scaffolds showed that the addition of HA and graphene/HA powders resulted in smaller pores and higher dimensional accuracy of the fabricated scaffolds. Mechanical evaluation showed that the addition of HA (0.3 gr) increased the mechanical properties of the scaffolds. Also, increasing the small amount of graphene (0.0045 gr) made the mechanical properties much higher than that of pure HA.

Adsorption, aggregation and sedimentation of titanium dioxide nanoparticles and nanotubes in the presence of different sources of humic acids.

Environmental behavior, bioavailability and risks posed by TiO2, nanomaterials (TiO2 NMs) in surface waters are affected by morphologies of the particles and geochemistry, including pH, inorganic and organic matter. Here, the adsorption, aggregation and sedimentation of TiO2 nanoparticles (TiO2 NPs) and nanotubes (TiO2 NTs) were investigated in the presence of Elliott Soil humic acid (HAE) and Suwannee River humic acids (HAS). The adsorption amount of HA on TiO2 NMs was inversely proportional to pH of solution. Maximum adsorption amount of HA on the surface of TiO2 NMs follows the order TiO2 NPs + HAE (236.05 mg/g) > TiO2 NTs + HAE (146.05 mg/g) > TiO2 NTs + HAS (70.66 mg/g) > TiO2 NPs + HAS (37.48 mg/g). Stability of TiO2 NPs and TiO2 NTs largely depended on their isoelectric point, morphology and solution pH in the absence of HA. Dispersion of TiO2 NMs was enhanced with solution pH deviated from the isoelectric point of nanomaterials due to electrostatic repulsion. Moreover, tubular structures of TiO2 NTs with higher length-diameter ratio seem to aggregate more easily than dose sphere-like TiO2 NPs. This might be due to their spherical structure enhancing steric repulsion. Notably, the adsorption of HA led to disagglomeration and significant stability of TiO2 NPs and TiO2 NTs due to steric hindrance under varying solution pH. In addition, adsorption time, concentration and sources of HA also influenced suspension/sedimentation behavior of TiO2 NPs and TiO2 NTs, and aromatic-rich HAE stabilized TiO2 NMs suspension more aggressively than aliphatic-rich HAS.

Incorporation of HA into porous titanium to form Ti-HA biocomposite foams

Ti foams are advanced materials with great potential for biomedical applications as they can promote bone ingrowth, cell migration and attachment through providing interconnected porous channels that allow the penetration of the bone-forming cells and provide them with anchorage sites. However, Ti is a bio-inert material and thus only mechanical integration is achieved between the porous implant and the surrounding tissue, not the chemical integration which would be desirable. In this work particles of a biologically active material (Hydroxyapatite, HA) are blended with titanium powder, and used to produce Ti foams through the use of Metal Injection Moulding (MIM) in combination with a space holder. This produces titanium foams with incorporated HA, potentially inducing more favourable bone response to an implant from the surrounding tissue and improving the osseointegration of the Ti foams. To be able to do this, samples need to show sufficient mechanical and biocompatibility properties, and the foams produced were assessed for their mechanical behaviour and in vitro biological response. It was found that the incorporation of high levels of HA into the Ti foams induces brittleness in the structure and reduces the load bearing ability of the titanium foams as the chemical interaction between Ti and HA results in weak ceramic phases. However, adding small amounts of HA (about 2 vol%) was found to increase the yield strength of the Ti foams by 61% from 31.6 MPa to 50.9 MPa. Biological tests were also carried out in order to investigate the suitability of the foams for biomedical applications. It was found that Ti foams both with and without HA (at the 2 vol% addition level) support calcium and collagen production and have a good level of biocompatibility, with no significant difference observed between samples with and without the HA addition.

Fulvic acid in foliar spray is more effective than humic acid via soil in improving coffee seedlings growth

ABSTRACTHumic (HA) and fulvic (FA) acids improve the nutrient availability and uptake by plants but some aspects of their agronomic use still need to be clarified. The effects of HA soil application and FA foliar application on the growth, Zn and B uptake by coffee seedlings were evaluated. HA was added to an Oxisol at concentrations 0, 10, 25, 50, 75 and 100 mg kg−1 (C-HA), in both limed (pH 6.2) and overlimed (pH 7.2) conditions. FA (0, 0.2, 0.5 and 1 g L−1 C-FA) was applied to coffee leaves in three different application modes (M): with 0.3% Zn and 0.6% B supplied via foliar (M1), 0.6% B and 1.2% Zn supplied via foliar (M2) and 1.2 mg kg−1 B and 6 mg kg−1 Zn supplied via soil (M3). HA addition in soil significantly (p < 0.05) reduced leaf B and Zn accumulation and coffee growth in both pH conditions. In the M1 and M2, FA application significantly (p < 0.05) increased the shoot growth at 0.59 and 0.45 g L−1 and B accumulation at 0.96 and 0.45 g L−1 C-FA. Foliar application of C-FA, instead soil application of C-HA, is a suitable practice to improve coffee seedlings growth and nutrition on Oxisol.

Researches Regarding the Improvment of Different Dental Contemporary Composite Materials Structure

The purpose of this study was to test the structural improving that may be acquired by adding hydroxyapatite microparticles bearing or not silver nanoparticles to three different commercial products commonly used in dental practice. The practical part of this study consisted in the preparation of a common protocol of nine samples resulting from the creation of cavities and their filling similarly to the solving of different clinical situations of carious processes, extracted teeth belonging to both the anterior and the posterior area, with different architectures of the loss of dental substance. Before use, both HA and HA/AgNP have been subjected to calcination in an oven at 6000C for three hours in order to eliminate the residual organic matter. The structural changes have been studied on three types of composites known in the medical practice under the tradenames of Ceram X Duo, Swiss Tec and Herculite XRV Ultra. The structural changes materialized at the level of dentinal component are clearly visible in the SEM images recorded for each starting commercial material. Thus, the addition of HA with high polydispersity (within the range of tens of nanometers and several microns) was effective on lowering the surface rugosity and apparent macro-porosity, while enhancing the phase mixing and component cohesion, but only in the case of Ceram X Duo and Swiss Tec materials. For Herculite XRV Ultra these effects seems to be limited or even reversed, phenomenon that could be explained by the fact that this material already contains nano-fillers, and their concentration tends to saturation.

Preparation and properties of polylactide/hydroxyapatite/polydopamine composites

A series of poly(lactic acid)/hydroxyapatite/polydopamine (PLA/HA/PDA) composites were fabricated via soution blending and casting method using CH2Cl2 as solvents. The physicochemical properties of the resulting composites were characterized by Fourier transform infrared spectroscopy, X‐ray powder diffraction, scanning electron microscopy, thermogravimetric analysis, and Rheological analysis. Particularly, the in vitro degradation, hydrophilic of PLA/HA/PDA composites was systematically investigated. The influences of DA content on thermal stabilities, hydrophilic, and rheological behavior properties of composites were evaluated. The results showed that the addition of DA and HA not only improved the thermal stability of PLA, but also improved the hydrophilic of PLA‐based composites. The obtained PLA/HA/PDA composites may be a promising material for load‐bearing orthopedic implants. POLYM. ENG. SCI., 58:2256–2263, 2018. © 2018 Society of Plastics Engineers

Studies Regarding the Architectural Design of Various Composites and Nanofibres Used in Dental Medicine

The aim of this study was represented by the definition and testing of a new formulation strategy and the functionality of composite materials, while ensuring the optimization of the relevant properties for the dental restoration processes through the use of precise techniques of characterization, the modification and functionality of the components in view of obtaining results that are characterized by an optimum biomechanical and bioactive relation, in full agreement with the particularities of the dental structure that requires restoration. In view of obtaining new resistant composite structures we made a number of 10 samples including extracted teeth with various losses of dental substance and the structural modifications included 3 types of composites, whose structure was improved by the introduction of inorganic fillings based on hydroxyapatite and silver nanoparticles. All these structures were reinforced with two types of fibers, Reforpost fiber glass kit (Angelus) and Fiber post Schulzer Pre-silanized; With regard to the use of composite structures improved by HA addition, we notice a slight lacunary structure on the SEM images due to the properties of HA, an aspect present at much smaller dimensions in the silver � HA mix. The size of the grains associated with their continuous uniformity and adherence for the fibrillar structure stands out at the samples with hydroxyapatite, the first place as uniformity and adherence going to the composite of the nanofiller technology category.

Impact of water chemistry on surface charge and aggregation of polystyrene microspheres suspensions

The discharge of microplastics into aquatic environment poses the potential threat to the hydrocoles and human health. The fate and transport of microplastics in aqueous solutions are significantly influenced by water chemistry. In this study, the effect of water chemistry (i.e., pH, foreign salts and humic acid) on the surface charge and aggregation of polystyrene microsphere in aqueous solutions was conducted by batch, zeta potentials, hydrodynamic diameters, FT-IR and XPS analysis. Compared to Na+ and K+, the lower negative zeta potentials and larger hydrodynamic diameters of polystyrene microspheres after introduction of Mg2+ were observed within a wide range of pH (2.0–11.0) and ionic strength (IS, 0.01–500mmol/L). No effect of Cl−, HCO3– and SO42− on the zeta potentials and hydrodynamic diameters of polystyrene microspheres was observed at low IS concentrations (<5mmol/L), whereas the zeta potentials and hydrodynamic diameters of polystyrene microspheres after addition of SO42− were higher than that of Cl− and HCO3– at high IS concentrations (>10mmol/L). The zeta potentials of polystyrene microspheres after HA addition were decreased at pH2.0–11.0, whereas the lower hydrodynamic diameters were observed at pH<4.0. According to FT-IR and XPS analysis, the change in surface properties of polystyrene microspheres after addition of hydrated Mg2+ and HA was attributed to surface electrostatic and/or steric repulsions. These investigations are crucial for understanding the effect of water chemistry on colloidal stability of microplastics in aquatic environment.

Dual targeting system by supramolecular complex of folate-conjugated methyl-β-cyclodextrin with adamantane-grafted hyaluronic acid for the treatment of colorectal cancer

In our previous study, we demonstrated that folate-appended methyl‑β‑cyclodextrin (FA-M-β-CyD) was a promising antitumor agent for the treatment of folate receptor-α (FR-α)-expressing tumors. In the present study, to enhance the antitumor effect of FA-M-β-CyD against FR-α- and CD44-expressing colorectal cancer cells, we synthesized a dual targeting supramolecular complex composed of FA-M-β-CyD and adamantane-grafted hyaluronic acid (Ad-HA). The supramolecular complex of Ad-HA/FA-M-β-CyD showed higher cytotoxic activity in HCT116 cells (FR-α (+), CD44 (+)), a human colon cancer cell line, than FA-M-β-CyD alone. In addition, the cytotoxic activity of Ad-HA/FA-M-β-CyD was significantly impaired by the addition of FA and HA, as inhibitors of FR-α and CD44, respectively. Furthermore, tetramethylrhodamine isothiocyanate (TRITC)-labeled FA-M-β-CyD was efficiently internalized into HCT116 cells through supramolecular complexation with Ad-HA, compared to that of TRITC-FA-M-β-CyD alone. Additionally, Ad-HA/FA-M-β-CyD induced mitophagy in HCT116 cells. These results suggest that Ad-HA/FA-M-β-CyD targeted HCT116 cells, as well as induced mitophagy-mediated cell death. Notably, an intravenous injection of the Ad-HA/FA-M-β-CyD complex in a mouse model of colorectal cancer significantly ameliorated the growth of tumor polyps. Collectively, these results suggest that Ad-HA/FA-M-β-CyD has antiproliferation effects in tumors, based on the dual targeting activity.

Effect of ozonation on minocycline degradation and N-Nitrosodimethylamine formation

ABSTRACTThe objective of this study was to assess reactivity of Minocycline (MNC) towards ozone and determine the effects of ozone dose, pH value, and water matrix on MNC degradation as well as to characterize N-Nitrosodimethylamine (NDMA) formation from MNC ozonation. The MNC initial concentration of the solution was set in the range of 2–20 mg/L to investigate NDMA formation during MNC ozonation. Four ozone doses (22.5, 37.2, 58.0, and 74.4 mg/min) were tested to study the effect of ozone dose. For the evaluation of effects of pH value, pH was adjusted from 5 to 9 in the presence of phosphate buffer. MNC ozonation experiments were also conducted in natural water to assess the influence of water matirx. The influence of the typical component of natural water was also investigated with the addition of HA and NaHCO3 solution. Results indicated that ozone was effective in MNC removal. Consequently, NDMA and dimethylamine (DMA) were generated from MNC oxidation. Increasing pH value enhanced MNC removal but led to greater NDMA generation. Water matrices, such as HCO3− and humic acid, affected MNC degradation. Conversely, more NDMA accumulated due to the inhibition of NDMA oxidation by oxidant consumption. Though ⋅OH can enhance MNC degradation, ozone molecules were heavily involved in NDMA production. Seven transformation products were identified. However, only DMA and the unidentified tertiary amine containing DMA group contributed to NDMA formation.

Hyaluronan improves neither the long-term storage nor the cryosurvival of liquid-stored CD44-bearing AI boar spermatozoa.

Hyaluronan (hyaluronic acid, HA) apparently improves sperm survival in vitro and in vivo (oviduct), maintaining sperm motility and inducing capacitation, but not acrosome exocytosis, either by direct action as a macromolecule or via CD44 membrane receptors. This study explored ejaculated, liquid-extended pig spermatozoa to ascertain (i) the presence (Western blotting) and specific location (immunocytochemistry) of the CD44 receptor, using a specific monoclonal commercial antibody; (ii) whether the CD44 receptor changed location when exposed to bicarbonate, a capacitating trigger, in vitro; and (iii) whether the addition of HA, of molecular size comparable to that produced in the oviduct sperm reservoir (0.0625 to 2.0 mg/ml; 0 HA: control), to semen extenders would improve sperm liquid storage in vitro or cryosurvival post-freezing. Variables tested were sperm velocity and progressive motility (QualispermTM), sperm viability and acrosome status, membrane integrity and early destabilization, mitochondrial activation, and superoxide production (flow cytometry). The CD44 receptor presence in ejaculated, liquid-stored AI boar spermatozoa, as confirmed by a porcine-specific monoclonal antibody, maintained its membrane location under in vitro capacitation-inducing conditions. HA exposure to 24-, 48-, or 72-h liquid-stored (17–20ºC) spermatozoa lowered sperm velocity in membrane-intact spermatozoa, but increased mitochondrial superoxide production. Finally, HA addition during cooling did not improve cryosurvival but did increase mitochondrial activation and membrane destabilization in surviving cells. These results confirm the existence of a CD44 receptor in pig spermatozoa, but the usefulness of adding HA for long-term storage or cryopreservation of liquid-stored, extended boar semen remains in question, thereby warranting further non-empirical analyses of HA-sperm membrane interactions.

A novel nano-composite scaffold for cartilage tissue engineering

In this study, a hybrid Poly (lactic-co-glycolic acid) (PLGA)/ Hyaluronic acid (Ha)/ Fibrin/ 45S Bioactive Glass (45SBG) nanocomposite scaffolds seeded with human Adipose-Derived Mesenchymal Stem Cells (hADMSCs) were investigated as a construct for osteoarthritis (OA), articular cartilage (AC), and subchondral bone defects therapies. The bioactivity and biodegradation of the nanocomposite scaffolds were assessed in simulated body fluid (SBF) and phosphate buffer saline (PBS) solution, respectively. Furthermore, MTT analysis was performed in order to determine attachment and viability of hADMSCs. Ultimately, results indicated that bioactivity were increased in nanocomposite scaffolds as compared to the pure PLGA scaffold. As well as, biodegradation assay exhibited that the addition of Ha, fibrin, and 45SBG nanoparticles could modify the degradation rate of PLGA. The nanocomposite scaffolds were not showed any cytotoxicity and the hADMSCs were attached on the scaffolds and proliferate properly. According to our investigation, it was concluded that using natural and synthetic polymers along with BG nanoparticles may provide a suitable construct and could show a beneficial role in AC tissue engineering and OA therapy.