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Öğe Cellular Uptake and Transcytosis(Taylor and Francis, 2021) Barin G.; Gultekin Y.; Pezik E.; Ozturk N.; Kara A.; Vural I.Nanoparticles are suitable delivery systems for targeting of drugs, and extensive research in the field of nanomedicine is ongoing. Apart from cellular uptake, nanoparticles sometimes have to cross cellular barriers. Understanding the cellular uptake and transcytosis of nanoparticles are crucial for designing efficient nanoparticles. This chapter provides a review of cellular uptake mechanisms and transcytosis of nanoparticles. Also, the effect of the physicochemical characteristics of nanoparticles on their cellular internalization is also discussed. Although nanocarriers sometimes release their payload at the extracellular disease site and the released active ingredient enters the cells by itself to show its effect, another way is to deliver nanoparticles directly into cells, and then the payload is released there and it shows its effect. Electrostatic, van der Waals, and ionic forces between the cell and the nanoparticle and receptor-mediated recognition of opsonins are behind phagocytosis of nanoparticles. © 2022 Jenny Stanford Publishing Pte. Ltd.Öğe Classification of breast masses in mammogram images using KNN(Institute of Electrical and Electronics Engineers Inc., 2015) Alpaslan N.; Kara A.; Zencir B.; Hanbay D.Breast cancer is one of the most deadly diseases for women. Mammogram is very important imaging technique used diagnosis in early stages of breast cancer. In this study, a decision support system which helps experts to examine mammogram images in the fight against breast cancer is developed. In this study, firstly several preprocesses are applied to mammogram to make image clear and segmentation of mass is provided with an appropriate threshold value. After the segmentation processes, features of the tumor mass are obtained. The obtained features are classified as normal, benign or malignant using kNN (k-nearest neighbours) classifiers. In this study, its have been were shown that, effect of kurtosis, skewness and wavelet energy features on classification performance is shown. As a result, it has been seen that, these features improve the classification performance. © 2015 IEEE.Öğe Evaluation of antitumor activity of a non-steroidal anti-inflammatory drug, ibuprofen, by a targeted nanoparticulate system(Colegio de Farmaceuticos de la Provincia de Buenos Aires, 2017) Ozturk N.; Kara A.; Vural I.In this study we aimed to develop a new targeted nanoparticulate system to obtain site specific delivery of ibuprofen and to determine its antitumor efficiency. The potential effect of ibuprofen as an antitumor agent was investigated on breast cancer cells based on a targeted delivery system. Ibuprofen was encapsulated to poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles. PLGA nanoparticles were fabricated by nanoprecipitation method and optimized in terms of certain parameters. Then, 520C9 monoclonal antibody (mAb) was chemically conjugated to carboxylic acid end group of PLGA nanoparticles (NPs) that specifically targeted human breast adenocarcinoma cell line (MCF-7). NP-mAb combined Ibuprofen encapsulated formulations were evaluated on characterization of particle size, encapsulation efficiency, drug loading capacity, and antitumor activity. The results demonstrated that optimized Ibuprofenloaded PLGA nanoparticles prepared by nanoprecipitation technique had an ideal particle size and polydispersity index. The encapsulation efficiency of optimized nanoparticles was relatively high, 92.9 ± 9.0%. Also, this system had significantly reduced the cell viability on MCF-7 cell line when compared with free ibuprofen solution at the same concentration. Above all, antibody-conjugated nanoparticles showed lower cell viability (12%) than the non-targeted system. Results indicated that ibuprofen-loaded nanoparticles had significant antitumor activity on MCF-7 cells even at relatively low concentrations. mAb conjugated drug-loaded nanoparticles were successfully fabricated and this system might be a promising approach for delivery of ibuprofen in treatment of breast cancer. © 2017, Colegio de Farmaceuticos de la Provincia de Buenos Aires. All rights reserved.Öğe Evaluation of Stimuli-Sensitive Nanoparticles in vitro(Taylor and Francis, 2021) Ozturk N.; Kara A.; Vural I.Nanoparticles are advantageous systems due to unique properties they present when they are used as drug delivery systems. One of the most intriguing approaches to obtain a desirable in vivo fate for nanoparticles is designing stimuli-responsive nanoparticles. Stimuli-responsive behavior can be obtained by using stimuli-responsive materials for forming of nanoparticles. Nanocarriers lead to some adverse effects, including uncontrollable drug release and biodistribution, because of some intracellular and extracellular barriers. In clinical use controlled-release nanosized drug delivery systems are present, but many of these controlled-release systems offer either constant or decreasing drug release and they are not sensitive to changes in the body that occur due to pathologies or external stimuli. Local abundance of enzymes at the tumor site is thought to provide drug release at the desired site, while in normal tissues low expression of enzymes is considered insufficient to cause drug release. © 2022 Jenny Stanford Publishing Pte. Ltd.Öğe Micrococcus sedentarius bacteraemia presenting with haemophagocytic syndrome in previously healthy boy(2006) Kuskonmaz B.; Kara A.; Özen M.; Cengiz A.B.; Özen M.; Seçmeer G.; Gürgey A.Haemophagocytic syndromes are the clinical manifestation of an increased macrophagic activity with haemophagocytosis. Infection-associated HS was originally described by Risdall in 1979, in viral disease. Since the initial description HS has also been documented in patients with bacterial, parasitic or fungal infections. We describe a case of Micrococcus sedentarius bacteraemia in a previously healthy 10-y-old boy with haemophagocytic syndrome. Species of micrococci are generally considered as non-pathogenic commensals that colonize the skin, mucosae and oropharynx. We report the first case of Microccoccus sedentarius bacteraemia in an immunocompetent host and first case of HS associated with Micrococcus species. © 2006 Taylor & Francis.
