Browsing by Author "Uskudar Guclu, Aylin"

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Electrospinning of linezolid loaded PLGA nanofibers: effect of solvents on its spinnability, drug delivery, mechanical properties, and antibacterial activities
(2020) Eren Boncu, Tugba; Ozdemir, Nurten; Uskudar Guclu, Aylin; 0000-0002-1872-028X; 31905297; AAU-6196-2020
Objective: The choice of a desirable solvent/solvent system is fundamental for optimization of electrospinning by altering the rheological and electrostatic properties of the polymer solutions. Methods: The effects of the solvents and their properties on the viscosity and spinnability of the polymer solutions and the diameter, morphology, in vitro drug release, drug release mechanisms, antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and mechanical properties of electrospun poly-(d,l-lactide-co-glycolide) (PLGA) nanofibers were investigated. Dichloromethane (DCM), dimethylformamide (DMF), various ratios of DCM:DMF, and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) were used as solvents. Results: Although solutions containing DCM/DMF alone were not spinnable, different ratios of DCM:DMF and HFIP were determined as suitable solvents to produce nanofibers because of high enough conductivity, viscosity, and low enough surface tension of the solutions. The DCM:DMF ratio was highly effective on viscosity, nanofiber diameter, morphology, and linezolid release rate. The viscosity of HFIP containing solution was higher and the obtained nanofibers were thicker and smoother with better mechanical properties. The release of nanofibers containing HFIP at a concentration of 10% w/v PLGA was more prolonged than nanofibers containing DCM:DMF mixture. The effect of linezolid content on nanofibers was also investigated. As the amount of linezolid increased, nanofiber diameter and drug release increased and bead formation was observed. While antibacterial activity with nanofibers for which DCM:DMF was used, lasted for 13 days, it was extended to 16 days in nanofibers for which HFIP was used. Conclusions: Type and ratio of the solvent system affected viscosity and spinnability of the solutions, the average nanofiber diameter, morphology, in vitro activity and mechanical properties of the obtained electrospun nanofibers.
Predominant Mutations of SARS-CoV-2: Their Geographical Distribution and Potential Consequences
(2021) Unlu, Sezin; Uskudar Guclu, Aylin; Basustaoglu, Ahmet; 0000-0001-7490-7981; 0000-0002-1872-028X; AAQ-4702-2021; AAU-6196-2020
Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) emerged in late December 2019 in Wuhan, China. More than 83 million people have been infected, and more than 1.8 million people have died, as reported to the World Health Organization on the 3rd of January, 2021. Analysis of genetic variations is critical for understanding the spreading pattern of SARS-CoV-2 across several countries. This review aimed to gather information about the prominent mutations of SARS-CoV-2 by analyzing the origin, viral pathogenesis, and mutation rate. Moreover, we concluded their potential impacts on SARS-CoV-2 therapeutics. Mutations in the spike protein (D614G, N501Y, E484K, A222V, S477N, and G485R), ORF1ab (P323L, N628N, Y455Y, A97V, and F106F), nucleocapsid protein (R203K and G204R), ORF8 (L84S), and ORF3a (Q57H and G251V) were examined in this review by analyzing relevant articles from the beginning of the current pandemic to the most recent date. A detailed analysis of articles demonstrates that D614G is the major variation distributed globally, and its frequency increased rapidly from early in March, followed by several other variations in either spike or different proteins. In addition, it was seen that the currently circulating N501Y and E484K variants revealed a public concern regarding vaccines' efficacy. Investigation of variations of SARS-CoV-2 would lead to understanding their potential mechanism of action against SARS-CoV-2, thereby suggesting suitable therapeutics. Several mechanisms were suggested to have a role in SARS-CoV-2 mutation rate and evolution. Possible therapeutics and vaccines against SARS-CoV-2 were proposed.
Prevalence of CMV DNA in Blood Donors in a Regional Blood Center in Turkey
(2022) Uskudar Guclu, Aylin; Yilmaz, Soner; Baysallar, Mehmet; Ayci, Ismail Yasar; 0000-0002-1872-028X; AAU-6196-2020
Cytomegalovirus (CMV) infections with a high seroprevalence rate in adults are often asymptomatic or mild. The current prevalence of CMV DNA in Turkey is not known. This study aimed to find out the prevalence and quantity of CMV DNA in blood donors by PCR. Totally 1003 samples were collected between March and June 2016 at a regional blood bank for detection of CMV DNA in healthy blood donors by quantitative real-time PCR. CMV-DNA positive samples were tested for the presence of anti CMV IgM and IgG by ELISA. Among 1003 donors, 973 (97.01%) were male and 30 (2.99%) were female. Age distribution of donors was between 18-64; mean age was 27. Most of the donors were between 18-30 years old (75.47%) and male (97.01%). One donor was found as CMV DNA positive (0.099%). The DNA quantity for positive donation was 1,75x10(2) IU/ml. CMV DNA positive sample was positive for IgG, whereas negative for IgM. Although the seroprevalence of CMV is high in our country the CMV DNA prevalence was found very low (0.099%). Testing of CMV DNA in blood donation particularly for some specific patient groups and the clinical follow-up of blood donation with low level of CMV DNA should be considered.