Özge Erdemli

Characteristics and release profiles of MPEG-PCL-MPEG microspheres containing immunoglobulin G

Polyester-polyether type block copolymers have attracted attention in the area of drug delivery systems with their capability in providing a broad range of amphiphilic characteristics. The aim of the present work was to prepare and characterize immunoglobulin G (IgG) loaded methoxy poly(ethylene glycol)-poly(ɛ-caprolactone)-methoxy poly(ethylene glycol) (MPEG-PCL-MPEG) microspheres as potential carrier for therapeutic monoclonal antibodies used in clinics. MPEG-PCL-MPEG triblock copolymer was synthesized by ring-opening polymerization of ɛ-caprolactone initiated by MPEG and then characterized. Microspheres were prepared by double emulsion-solvent evaporation method and their properties were compared with those of PCL microspheres. Microspheres had spherical shape with a mean particle size around 6 μm. MPEG-PCL-MPEG microspheres had higher encapsulation efficiency than PCL microspheres. After 90 days of release, 30±2% and 57±3% of the bioactivity of IgG released from non-irradiated PCL and MPEG-PCL-MPEG microspheres were protected, respectively. Presence of MPEG in microspheres provided more controlled IgG release rate and protected IgG from denaturation during γ-irradiation (20±3% and 49±2% for PCL and MPEG-PCL-MPEG microspheres, respectively). In vitro cytotoxicity tests revealed that both MPEG-PCL-MPEG and PCL microspheres had no toxic effect on cells. This study showed that MPEG-PCL-MPEG microspheres are promising delivery systems for therapeutic monoclonal antibodies.

In vitro evaluation of effects of sustained anti-TNF release from MPEG-PCL-MPEG and PCL microspheres on human rheumatoid arthritis synoviocytes.

Anti-tumor necrosis factor α (TNFα) drugs such as etanercept (ETN) have been mostly used in systemic treatment of rheumatoid arthritis. To eliminate the side effects in long-term treatments and to achieve a local sustained anti-inflammatory effect, a controlled drug delivery system is needed for anti-TNFα drugs. This study aims to develop novel injectable microcarriers of ETN that can provide long-term controlled release of this protein drug upon intra-articular application. In this study, poly(ε-caprolactone) (PCL) and its copolymer with poly(ethylene glycol), methoxypoly(ethylene glycol)-poly(ε-caprolactone)-methoxypoly(ethylene glycol) microspheres (MPEG-PCL-MPEG) were compared for their prospective success in rheumatoid arthritis treatment. Microspheres with smooth surface of a mean particle diameter of approximately 5 μm were prepared with both polymers. MPEG-PCL-MPEG microspheres had higher encapsulation efficiency than PCL microspheres. The activity of encapsulated ETN within MPEG-PCL-MPEG microspheres also retained while 90% of the activity of ETN within PCL microspheres could retain during 90-day release. MPEG-PCL-MPEG microspheres showed faster ETN release compared to PCL microspheres in various release media. Cumulative amounts of ETN released from both types of microspheres were significantly lower in cell culture medium and in synovial fluids than in phosphate buffered saline. This was mainly due to protein adsorption onto microspheres. Hydrophilic MPEG segment enhanced ETN release while preventing protein adsorption on microspheres compared to PCL. Sustained ETN release from microspheres resulted with a significant decrease in pro-inflammatory cytokines (TNFα, IFNγ, IL-6, IL-17) and MMP levels (MMP-3, MMP-13), while conserving viability of fibroblast-like synoviocytes compared to the free drug. Results suggest that MPEG-PCL-MPEG is a potential copolymer of PCL that can be used in development of biomedical materials for effective local treatment purposes in chronic inflammatory arthritis owing to enhanced hydrophilicity. Yet, PCL microspheres are also promising systems having good compatibility to synoviocytes and would be especially the choice for treatment approach requiring longer term and slower release.

Influence of excipients on characteristics and release profiles of poly(ε-caprolactone) microspheres containing immunoglobulin G.

Protein instability during microencapsulation has been one of the major drawbacks of protein delivery systems. In this study, the effects of various excipients (poly vinyl alcohol, glucose, starch, heparin) on the stability of encapsulated human immunoglobulin G (IgG) in poly(ε-caprolactone) (PCL) microspheres and on microsphere characteristics were investigated before and after γ-sterilization. Microspheres formulated without any excipients and with glucose had a mean particle size around 3-4μm whereas the mean particle sizes of other microspheres were around 5-6μm. Use of PVA significantly increased the IgG-loading and encapsulation efficiency of microspheres. After γ-irradiation, IgG stability was mostly maintained in the microspheres with excipients compared to microspheres without any excipients. According to the μBCA results, microspheres without any excipient showed a high initial burst release as well as a fast release profile among all groups. Presence of PVA decreased the loss in the activity of IgG released before (completely retained after 6h and 15.69% loss after 7days) and after γ-irradiation (26.04% loss and 52.39% loss after 6h and 7days, respectively). The stabilization effect of PVA on the retention of the activity of released IgG was found more efficient compared to other groups formulated with carbohydrates.

Clinoptilolite/PCL-PEG-PCL composite scaffolds for bone tissue engineering applications

The aim of this study was to prepare and characterize highly porous clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) composite scaffolds. Scaffolds with different clinoptilolite contents (10% and 20%) were fabricated with reproducible solvent-free powder compression/particulate leaching technique. The scaffolds had interconnective porosity in the range of 55–76%. Clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) scaffolds showed negligible degradation within eight weeks and displayed less water uptake and higher bioactivity than poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) scaffolds. The presence of clinoptilolite improved the mechanical properties. Highest compressive strength (5.6 MPa) and modulus (114.84 MPa) were reached with scaffold group containing 20% clinoptilolite. In vitro protein adsorption capacity of the scaffolds was also higher for clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) scaffolds. These scaffolds had 0.95 mg protein/g scaffold adsorption capacity and also higher osteoinductivity in terms of enhanced ALP, OSP activities and intracellular calcium deposition. Stoichiometric apatite deposition (Ca/P=1.686) was observed during cellular proliferation analysis with human fetal osteoblasts cells. Thus, it can be suggested that clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) composite scaffolds could be promising carriers for enhancement of bone regeneration in bone tissue engineering applications.

Öğretmenlerin İşten Geri Çekilme Davranışları ve Çalışma Etiği ile İlişkisi

Problem Situation: People experience ups and downs in their job satisfaction and motivation levels at different points of their work lives for various reasons. One of the outputs of low job satisfaction and motivation is defined as “withdrawal behaviors” in the literature. Withdrawal behaviors are any employee behavior of withdrawal from duties and responsibilities as a result of a distance that grows between the employee and the organization. It is an important necessity to investigate such behaviors at educational institutions. Determining teachers’ withdrawal behaviors will be useful in enabling more effective and successful performance of their job. Also, considering that their withdrawal behaviors adversely affect the students’ success, investigation of such behaviors is an important necessity in respect to the quality of education. Purpose: This study aims to identify teachers’ withdrawal behaviors and the relationship between such behaviors and work ethics based on the views of teachers and school administrators serving in public elementary schools. Method: Designed in single and relational screening models, the study was conducted using a mixed research method. The study sample in quantitative dimension is comprised of 381 elementary school teachers and 198 elementary school administrators. Under the quantitative dimension of the study, 15 elementary school teachers and 15 school administrators were interviewed. Teachers’ withdrawal behaviors were studied using the “Withdrawal Behaviors Scale” and their views on work ethics were studied using the “Work Ethics Scale.” The quantitative data was collected using a semistructured form. This article has been produced from the graduate thesis supervised by Professor Dr. İnayet Aydın at the Department of Education Management and Policy, Faculty of Educational Sciences, Ankara University. Research Assistant, Ankara University, Faculty of Educational Sciences, ozge.erdemli8787@gmail.com

In vitro/in vivo comparison of cefuroxime release from poly(ε‐caprolactone)–calcium sulfate implants for osteomyelitis treatment

This study aimed to investigate the release of cefuroxime axetil (CF) and calcium from poly(ε‐caprolactone) (PCL)–calcium sulfate (CaS) implants (PCL:CaS 2:1–10% CF; PCL:CaS 2:1–20% CF; PCL:CaS 1:1–10% CF) for treating infectious bone diseases. Bioactivity, crystallinity and strength, and release profiles under standard and pressurized release conditions were studied. PCL:CaS 2:1–20% CF had slower release than 10% loading. These groups had no significant change in CF and Ca release in response to pressure. The PCL:CaS 1:1 group had the slowest release despite having higher CaS, probably due to more compaction of discs. In contrast, pressure caused significant differentiation of CF and Ca2+ release. The presence of CaS enhanced mechanical properties and bioactivity of discs. SEM and XPS results showed calcium‐phosphate containing accumulations on surfaces upon SBF incubation. CF‐loaded implants were applied in a rabbit osteomyelitis model. In vivo CF release was enhanced with increased CaS proportions, suggesting that in vivo release conditions are closer to pressurized in vitro conditions. In the control group, there was still some inflammation in the bone and no complete coverage with bone was achieved in the defect site. Discs provided a suitable surface for regeneration of bone. However, bone formation in the PCL:CaS 1:1 disc implanted group was more complete and regular than in the 2:1 group.

Öğretmenlik Meslek Etiği Açısından Hediye Alma: Örnek Olay Ekseninde

Bu calismanin amaci ogretmenlerin hediye alma davranisini hakli gosterirken ve ussallastirirken kullandiklari yaklasimlari tespit etmektir. Bu amacla ogretmenlerin goruslerine basvurulmustur. Calisma ogretmenlerin hediye alma davranisini nasil hakli gostermeye calistiklarini derinlemesine incelediginden nitel arastirma yontemlerinden durum calismasi benimsenerek yapilmistir. Bu arastirmanin calisma grubunu Ankara ilinde kamu ilkokul ve ortaokullarinda gorev yapan 15 ogretmen olusturmaktadir. Calismada ogretmenlere hediye alma durumuyla ilgili bir ornek olay sunularak bu durumda ne yapacaklari ve bu kararlarinin gerekceleri sorulmus, buna gore bu kararlarini hakli gosterirken ve ussallastirirken hangi yaklasimlari kullandiklari belirlenmeye calisilmistir. Toplanan veriler betimsel analiz teknigi kullanilarak analiz edilmistir. Arastirma bulgularina gore ogretmenlerin cogunun kendilerine verilen ornek olayda etik karar verdikleri, ancak bazi ogretmenlerin cesitli gerekcelerle hediye almayi kabul edeceklerini belirtikleri tespit edilmistir. Ogretmenlerin bu etik disi kararlarini hakli gosterirken “Sahte gereklilikler tuzagi” ussallastirma yaklasimini kullandiklari gorulmustur.

Teacher’s Views Regarding the Social Status of the Teaching Profession

Abstract This study aims to investigate the views of teachers from different generations (X-Y) working in public elementary schools, specifically in different levels of the social status. In this study, a qualitative research methods called phenomenological design was utilized. The study group is comprised of 20 teachers working in public elementary schools, 10 of whom are from generation X and 10 of whom are from generation Y. The collected interview data was analyzed using content analysis. According to the research findings, teachers view the teaching profession as having a lower status compared with other professions (88%) and previous years (100%). Teachers indicate that the reasons for this attitude are new top management policies (24.4%) and low pay (14.6%). The most frequently mentioned policy of the Ministry of Education that affects teacher social status is the 147 Hotline/Grievance Line (43.75%). Some suggestions based on results were included in the study.

PReS-FINAL-2086: In vitro investigation of the sustained therapeutic effect of etanercept loaded microspheres on human rheumatoid arthritis fibroblast-like synoviocytes

Anti-TNFα treatment has become an important part of our systemic treatment in chronic inflammatory arthritis. Local application to the joint produces transient clinical improvement since the drug quickly leaves the joint.