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Dive into the research topics where Ibrahim Yilmaz is active.

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Featured researches published by Ibrahim Yilmaz.


The Open Orthopaedics Journal | 2012

Synergistic Effect of TGF-β1 And BMP–7 on Chondrogenesis and Extracellular Matrix Synthesis: An In Vitro Study

Alper Gokce; Ibrahim Yilmaz; Rifat Bircan; Murat Tonbul; Nevzat Selim Gokay; Cigdem Gokce

Introduction: The purpose of the present study seeks to determine the signal timing of BMP–7 and TGF-β1 from a novel chitosan based hydrogel system that may affect chondrocyte proliferation resulting in the presence of a synergism seen conspicuously in consecutive controlled delivery. Methods: Four groups of cultured chondrocytes were seeded on a novel designed chitosan based hydrogel. The hydrogel was left empty (control) in one group and loaded with BMP–7, TGF-β1 and their combination in the other groups, respectively. Hydrogel structure was analyzed with scanning electron microscope. The release kinetics of Growth Factors (GFs) was determined with ELISA. Chondrocyte viability and toxicity after being tested with MTS and collagen type II synthesis, were quantified with western blotting. Canonical regression analysis was used for measuring statistical evaluation. Results: Chitosan based hydrogel allowed controlled release of GFs in different time intervals for BMP–7 and TGF-β1. Double peak concentration gradient was found to be present in the group loaded with both GFs. In this group, substantially higher chondrocyte growth and collagen synthesis were also detected. Conclusions: We concluded that, chitosan based hydrogel systems may be adjusted to release GFs consecutively during biodegradation at the layers of surface, which may increase the cell number and enhance collagen type II synthesis.


Journal of Ultrasound in Medicine | 2011

Sonographically Guided Corticosteroid Injection for Treatment of Plantar Fasciosis

Arda Kayhan; Nevzat Selim Gokay; Rümeysa Alpaslan; Mehmet Demirok; Ibrahim Yilmaz; Alper Gokce

The purpose of this study was to prospectively investigate the effect of sonographically guided corticosteroid injection on the clinical and radiologic responses in patients with proximal plantar fasciosis.


Journal of Infection and Public Health | 2016

Are the leading drugs against Staphylococcus aureus really toxic to cartilage

Mustafa Dogan; Mehmet Isyar; Ibrahim Yilmaz; Bulent Bilir; Duygu Yasar Sirin; Selami Cakmak; Mahir Mahirogullari

Many studies have shown that the toxic effects of local antibiotics on bone and cartilage limit orthopedic surgeons. In this study, we evaluated three antibacterial agents used locally to treat highly mortal and morbid diseases in the field of orthopedics, such as septic arthritis. Are vancomycin, teicoplanin, and linezolid, which are archenemies of Staphylococcus aureus, really toxic to chondrocytes? The purpose of the study was to investigate the effects of antibiotics, which are used against S. aureus, on human chondrocytes in vitro. Primary cell cultures obtained from gonarthrosis patients were divided into two main groups. One of these groups was designated as the control chondrocyte culture. The other group was divided into three subgroups, and each group was exposed to vancomycin, teicoplanin, or linezolid. Cell culture samples were characterized by immunophenotyping following incubation with the three different antibiotics. Before and after the agents were administered, the cultures were subjected to inverted and environmental scanning electron microscopy. The number of live cells and the proliferation rate were monitored with the MTT-assay. We found that vancomycin, teicoplanin, and linezolid do not have chondrotoxic effects. Vancomycin, teicoplanin, and linezolid had no chondrotoxic activity during in vitro culture, which supports the argument that these agents can safely be used in orthopedic surgery, especially against methicillin-resistant S. aureus agents.


Journal of Orthopaedic Surgery and Research | 2015

Are biological agents toxic to human chondrocytes and osteocytes

Mehmet Isyar; Bulent Bilir; Ibrahim Yilmaz; Selami Cakmak; Duygu Yasar Sirin; Aliye Yıldırım Güzelant; Mahir Mahirogullari

PurposeThe aim of the present study is to investigate the effects of biological agents (BAs) on human chondrocytes and osteocytes in vitro.MethodsPrimary cell cultures obtained from gonarthrosis patients were divided into four groups, two of which were designated as control cultures of chondrocyte and osteocyte, and the other two groups were exposed to BAs administered via the culture medium. Cultured cells were characterized by immunophenotyping. Before and after administration of the agents, the cultures were observed by inverted and environmental scanning electron microscopy (ESEM). The number of live cells and the proliferation rate were monitored by MTT assay.ResultsRituximab and adalimumab were the least toxic agents to chondrocytes, whereas adalimumab and etanercept were to osteocytes.ConclusionDuring periods of intense active inflammation, the concentration of the preferred BAs after inhibition of inflammation needs to be emphasized when their effects on cartilage and bone tissue are considered at the cellular level if the clinical practice is to continue.


Arthritis | 2013

How Different Methodologies of Harvesting and Analysing the Samples Affect the Test Results in Determining Joint Mediators

Ibrahim Yilmaz; Nevzat Selim Gokay; Rifat Bircan; Gamze Varol Saraçoğlu; Sergülen Dervişoğlu; Alper Gokce

Purpose. This study has researched the affect of different methodologies of harvesting and analysing the samples in determining the mediators emerging after the rat articular cartilage injury. Materials and Methods. One hundred and forty-four male wistar rats were divided into 2 groups. Synovial fluid samples were taken from all of the rats. We entered into the right knees of the rats in group I (n = 36) under anaesthesia and took cartilage tissue samples from their distal femur. Samples were taken as reference values for enzyme linked immunosorbent assay (ELISA) and histopathological evaluations. We entered into the right knees of the rats in group II (n = 108) and formed complete layer of cartilage injury in their medial femoral condyles. At the end of the 15th day, the rats were sacrificed after taking synovial fluid samples from their right knees creating defect in the rats in group II. The molecular markers in the synovial fluid and cartilage tissue samples which were taken from the experimental and control groups (MMP-9, MMP-13, TIMP-1, TNF-α, and NO) were analysed by direct or indirect methodologies. SPSS 18.0 Package program was used in the statistical evaluation. Students t-test where the measurement variables between the experimental and control groups were compared was applied. Receiver Operating Characteristics (ROC) curves were used in the determination of the diagnostic sufficiency from the tissue. Results. No difference was found between TIMP-1 (P = 0.67) and MMP-9 (P = 0.28) levels in synovial fluid and cartilage tissue. From the molecular markers, when MMP-9, MMP-13, NO, TIMP-1, TNF-α′, the area under ROC curve, and P values were examined, MMP-13 (P < 0.0001, 95% CI: 0.70–0.85), NO (P < 0.0001, 95% CI: 0.72–0.86), and TNF-α (P < 0.0001, 95% CI: 0.91–0.98) results were found to be statistically significant. Inferences. The indirect ELISA protocol which we apply for the cartilage tissue as an alternative to synovial lavage fluid is a reliable method which can be used in the determination of articular cartilage injury markers.


Journal of orthopaedics | 2016

A practical way to prepare primer human chondrocyte culture

Mehmet Isyar; Ibrahim Yilmaz; Duygu Yasar Sirin; Sercan Yalcin; Olcay Guler; Mahir Mahirogullari

Biological cartilage repair is one of the most important targets for orthopedic surgeons currently. For this purpose, it is mandatory to know how to prepare a chondrocyte culture. In this study, our purpose was to introduce a method enabling orthopedic surgeons to practice their knowledge and skills on molecular experimental setup at cellular level, based on our experiences from previous pilot studies. Thus, we believe it will encourage orthopedic surgeons.


Drug and Chemical Toxicology | 2017

Are chondrocytes damaged when rheumatologic inflammation is suppressed

Aliye Yıldırım Güzelant; Mehmet Isyar; Ibrahim Yilmaz; Duygu Yasar Sirin; Selami Cakmak; Mahir Mahirogullari

Abstract Aim: The use of biological agents (BAs) for treating diseases such as rheumatoid arthritis (RA), spondyloarthropathy, and systemic lupus erythematosus to reduce inflammation has been fruitful. Especially as part of the increasing number of studies on the intra-articular application of BAs, the effects of BAs on cartilage have been widely investigated. In the present study, the effects of rituximab, abatacept, and adalimumab, all approved antirheumatic agents, on human primary chondrocytes were investigated comparatively and on the molecular level through viability, proliferation, and toxicity analyses. Materials and methods: Osteochondral tissues from the distal femur and proximal tibia were resected during total knee arthroplasty from patients (n = 3) with confirmed gonarthrosis in whom all medical or conservative treatments had failed. Standard human primary chondrocyte cell culturing was carried out. Immunophenotyping was performed on the cells that adhered to the flask, and their chondrotoxicity was observed using a flow cytometry device. Images of the cells showing chondrotoxicity were analyzed using invert and environmental scanning microscopes, and microimages were obtained. The MTT-enzyme linked immunosorbent assay was performed to observe the toxic effects of BAs on the proliferation of chondrocytes at 24 and 48 h. The results were analyzed using the number of cells and proliferation; statistical comparisons among the groups were carried out using one-way ANOVA. The alpha significance level was set at <0.01. Results: These pharmaceutical agents were chondrotoxic, especially on viability and proliferation (p = 0.0000). Conclusion: BAs are generally used during active inflammation, and following the management of inflammation, their dosage should be determined taking into consideration their cellular-level toxic effects on chondrocytes.


Journal of orthopaedics | 2016

Is there a treatment protocol in which platelet-rich plasma is effective?

Ibrahim Yilmaz; Semih Akkaya; Mehmet Isyar; Ahmet Guray Batmaz; Olcay Guler; Kadir Oznam; Akin Ugras; Mahir Mahirogullari

AIM We aimed to reveal whether there are prospective suggestions for effective and standard platelet-rich plasma applications. METHODS We searched for clinical trials and traced all the references of incorporated documents. RESULTS In literature, there was no study indicating which disease is treated by which mechanism of action, how much dose and content are prepared and applied, when the treatment is applied and how many cures are applied. CONCLUSION Guides introducing which concentrations of PRP are used for which diseases are to be prepared immediately by a committee which is comprised of primarily orthopedists, clinical pharmacologists and toxicologists.


Journal of Infection and Public Health | 2016

Are treatment guides and rational drug use policies adequately exploited in combating respiratory system diseases

Mustafa Dogan; Levent Cem Mutlu; Ibrahim Yilmaz; Bulent Bilir; Gamze Varol Saraçoğlu; Aliye Yıldırım Güzelant

The aim of the present study was to increase awareness regarding the rational use of medicines. The data were obtained via the Material Resources Management System Module of the Ministry of Health. For the appropriateness of treatments, the Global Initiative for Asthma, the Global Initiative for Chronic Obstructive Lung Disease, and the guidelines for the rational use of medicines were used. We also investigated whether any de-escalation method or physical exercise was performed. Statistical analyses were performed using descriptive statistics to determine the mean, standard deviation, and frequency. The results showed that healthcare providers ignored potential drug reactions or adverse interactions, and reflecting the lack of adherence to the current treatment guides, 35.8% irrational use of medicines was recorded. Thus, de-escalation methods should be used to decrease costs or narrow the antibiotic spectrum, antibiotic selection should consider the resistance patterns, culturing methods should be analyzed, and monotherapy should be preferred over combination treatments.


American Journal of Otolaryngology | 2015

In vitro analysis of a novel controlled release system designed for intratympanic administration of N-acetylcysteine: a preliminary report.

Zafer Ciftci; Mahmut Deniz; Ibrahim Yilmaz; Halide Güneş Çiftçi; Duygu Yasar Sirin; Erdogan Gultekin

The aim of this in-vitro experimental study was to design a novel drug delivery system that may permit controlled release of N-acetylcysteine (NAC) following intratympanic administration. The system was composed of two different solutions that attained a hydrogel form within seconds after getting into contact with each other. The authors performed swelling, pH and temperature tests and analysis of controlled release of NAC from this novel controlled release system. For the structure and porosity analysis of the hydrogel, an environmental scanning electron microscope (SEM) was used. The diameter of designed hydrogel showed an increase when pH was increased. In addition, in comparison to acidic values, the pore diameter of the hydrogel increased significantly especially in physiological level. The increase in the pore diameter was also directly proportional to the increase in temperature. Spectrophotometric analysis showed that the amount of NAC released into the medium was statistically significant (p=0.038, t=-2.18, 95% CI; DF: 27). SEM analysis of the samples revealed a smooth surface topography and numerous porous structures. The authors are of the opinion that the designed hydrogel may be used as an alternative method for intratympanic delivery of NAC for otoprotective purposes. The disadvantages of intratympanic injection of the drug in its liquid form, including leakage through eustachian tube, restraining the patient in an uncomfortable position, necessity for repetitive injections and dose dependent inflammation of the middle ear epithelium, may also be avoided. Further in vivo studies should be conducted to assess its tolerability and effectivity.

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Alper Gokce

Namik Kemal University

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