GO containing PHBHX bone scaffold: GO concentration and in vitro osteointegration

Trauma, congenital abnormalities or cancer-induced bone defects can be treated with tissue engineering products. Graphene oxide-containing polymeric scaffolds are used as an artificial extracellular matrix, acting as an environment where cells can grow and turn into living tissues. In the presented study, primarily cytotoxicity of graphene oxide was determined depending on the concentration. According to the cytotoxicity results, two different scaffolds containing low and high concentrations of GO were prepared and usability in bone tissue engineering was examined. For this purpose, water uptake, in vitro degradation and mechanical properties of the scaffolds were determined. On the predetermined days, MC3T3 cells proliferation and ACTB, COL1A1, OCN, OPN, RUNX2 gene expression were determined. According to the results, MC3T3 cell proliferation was increased when the incubation time increased, and also, gene expression related to bone tissue formation was increased. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature

Volume CXIV, Number 4, November 7, 1996

Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population.Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014.Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosis) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto's thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%.Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespa

Osteoblast activity on anodized titania nanotubes: Effect of simulated body fluid soaking time

Bayram, Cem (Aksaray, Yazar) Erol Demirbilek, Melike (Aksaray, Yazar)Early phase osseointegration is crucial for orthopedic implants. For the improvement of osseointegrative properties of orthopedic implants several surface modification methods such as acid etching, hydroxyapatite (HA) coating and sandblasting can be applied. In this article titanium implants were anodized to possess nanotubular titania structures on the surface. Titania nanotube structures with a 45-50 nm of average inner diameter were obtained and to enhance bioactivity, samples were soaked in 10X simulated body fluid (SBF) for apatite deposition on surface for different time periods (1, 2, 3, 5, 8 hours). Apatitic calcium phosphate deposited surfaces were analyzed with infrared spectrometry and wettability studies. Effect of soaking time on osteoblast cell was investigated by cell viability, alkaline phosphatase activity tests and morphological evaluations. As a result, 3 hours of soaking time was found as the optimum time period (p < 0.005). This in vitro study indicated that soaking in 10X SBF can be a rapid and economical technique to enhance osseointegration of anodized titanium implants however excess and/or uncontrolled HA coating of titania layer limits the bioactive potential of the implant

Distinguishability analysis of an induced current EIT system using discrete coils

The distinguishability of a discrete coil induced current electrical impedance tomography system is analysed. The solution methodology of the forward problem of this system is explained. An optimization procedure using this forward problem solution is developed to find optimum currents that maximize the distinguishability. For the concentric inhomogeneity problem, it is shown that the coil currents can be optimized to focus the current density in any desired location, in the field of view. Optimum coil currents under the constraints of limited peak coil currents and limited total power are determined. Examples that demonstrate the performance of the system are presented

N-Acetylglucoseamine Modified Alginate Sponges As Scaffolds For Skin Tissue Engineering

In the treatment of dermal wounds, wound-dressing materials prepared from natural mucopolysaccharides are widely used because of their advantages such as nonirritation, nontoxicity, and ease in topical application. In the present study, alginate hydrogels modified with N-acetyl glucose amine (NAG) were prepared as wound-dressing material. Physical, chemical, thermal, and mechanical properties of the hydrogels were studied. Cytotoxicity of the hydrogels on endothelial (HUVEC) and keratinocyte (HaCaT) cells were examined. Anti-and proinflammatory cytokine levels of human monocyte-macrophage cells (THP-1) stimulated with hydrogels were determined. According to the results, increasing the NAG concentration led to an increase in the swelling and nitrogen ratios in the hydrogels. Additionally, increasing the NAG concentration decreased elastic modulus and degradation time. Hydrogels were not cytotoxic on HaCaT and HUVEC cells. It stimulated IL-10 and TNF-alpha levels at a small rate.WoSScopu

A quasi-static analysis for a class of induced-current EIT systems using discrete coils

A discrete coil EIT system is investigated for the general case of an eccentric circular inhomogeneity. The solution methodology of the forward problem of this system is explained. An optimization procedure using this forward problem solution is developed to rind optimum currents that maximize the distinguishability. For an eccentric inhomogeneity problem, it is shown that the coil currents can be optimized to focus the current density in a region of interest. Optimum coil currents under limited peak coil currents constraint and limited total power constraint are obtained. Representative examples that demonstrate the performance of the system are presented

Preparation and characterization of magnetically responsive bacterial polyester based nanospheres for cancer therapy

WOS: 000306941400011PubMed: 22888751Polyhydroxyalkanoates (PHA) are natural, thermoplastic polyesters and due to their biocompatible and biodegradable properties they are good alternatives for the production of scaffolds for engineered tissues or nanoparticles for drug delivery. As a member of polyhydroxyalkanoate family, polyhydroxybutyrates (PHB) have been widely used as a biomaterial for in vitro and in vivo studies since their mechanical properties are very similar to conventional plastics. By using multi-emulsion technique, iron oxide particles were coated with polyhydroxybutyrate (PHB) polymer synthesized from Alcaligenes eutrophus bacteria and the magnetic carrier system was prepared accordingly. The bare nanoparticles and magnetic nanoparticles were morphologically, structurally and magnetically characterized by using Scanning electron microscope (SEM) and Atomic force microscope (AFM); Fourier Transform Infrared Spectrometry (FTIR), and Electron Spin Resonance (ESR) and Vibrating Sample Magnetometer (VSM) techniques, respectively. Particle size of PHB nanoparticles was determined by Zeta Sizer. It was found that the smallest particles were in the range of 239,43+/-5,25 nm in diameter. Concanavalin-A (Con-A) was used for targeting the Cancer cells while etoposide was used as drug. Con-A and etoposide were loaded onto the particles. Release studies of etoposide were evaluated and the system was optimized for the further in vivo applications. Finally different formulation magnetic PHB nanoparticles cytotoxicity were evaluated in cell culture studies and used He La cell line (cervical cancer cells) as a cancer cells and L929 cells (mouse fibroblast cells) as a non-cancer cell line.Hacettepe University Scientific Researches UnitThis project was supported by Hacettepe University Scientific Researches Unit and the authors would like to thank Bilkent University, Institute of Materials Science and Nanotechnology (UNAM)