Browsing by Author "Akan Z."
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Item Characterization of Polymeric Microneedle Arrays for Transdermal Drug Delivery(2013) Demir Y.K.; Akan Z.; Kerimoglu O.Microfabrication of dissolvable, swellable, and biodegradable polymeric microneedle arrays (MNs) were extensively investigated based in a nano sensitive fabrication style known as micromilling that is then combined with conventional micromolding technique. The aim of this study was to describe the polymer selection, and optimize formulation compounding parameters for various polymeric MNs. Inverse replication of micromilled master MNs reproduced with polydimethylsiloxane (PDMS), where solid out of plane polymeric MNs were subsequently assembled, and physicochemically characterized. Dissolvable, swellable, and biodegradable MNs were constructed to depth of less than 1 mm with an aspect ratio of 3.6, and 1/2 mm of both inter needle tip and base spacing. Micromolding step also enabled to replicate the MNs very precisely and accurate. Polymeric microneedles (MN) precision was ranging from ±0.18 to ±1.82% for microneedle height, ±0.45 to ±1.42% for base diameter, and ±0.22 to ±0.95% for interbase spacing. Although dissolvable sodium alginate MN showed less physical robustness than biodegradable polylactic-co-glycolic acid MN, their thermogravimetric analysis is of promise for constructing these polymeric types of matrix devices. © 2013 Demir et al.Item Analysis of radiofrequency ablation of small renal tumors in patients at high anesthetic and surgical risk: Urologist experience with follow-up results in the initial six months(Asian Pacific Organization for Cancer Prevention, 2013) Yuksel M.B.; Karakose A.; Gumus B.; Tarhan S.; Atesci Y.Z.; Akan Z.Background: To evaluate the results of various types of radiofrequency ablation (RFA) treatment of renal tumors in patients with excessive anesthetic and surgical risk. Materials and Methods: Data for RFA performed in in high risk patients were retrospectively evaluated. Other RFA applications in patients with no anesthetic and/or surgical risk were excluded. RFA was by ultrasound or CT guided percutaneous (USG/CT-PRFA) and retroperitoneally or transperitoneally laparoscopic (R/T-LRFA) techniques under general or local anethesia. Follow-up data of enhanced CT or MRI after 1, 3 and 6 months were analysed for twelve RFA applications. Results: The RFA applications included 4 (40%) left-sided, 5 (50%) right-sided and 1 (10%) bilaterally RFA (simultaneously 1 right and 2 left). The localizations of tumors were 2 (16.6%) upper, 5 (41.6%) mid and 5 (41.6%) lower pole. The RFA applications included 9 (75%) USG-PRFA, 1 (8.3%) CT-PRFA, 1 (8.3%) T-LRFA and 1 (8.3%) R-LRFA. The mean age was 65.3±8.5 (52-76) years. The mean tumor size was 29.6±6.08 (15-40) mm. No complications related to the RFA were encountered in any of the cases. Failure (residual tumour) was determined in 8.3% (1/12) of USG-RFA application. The success rate was thus 91.7% (11/12). Other 1st, 3rd and 6th months follow-up data revealed no residua and recurrence. Conclusions: RFA application appears to be safe as a less invasive and effective treatment modality in selected cases of small renal tumors in individuals with excessive anesthetic and also surgical risk.Item Sodium Alginate Microneedle Arrays Mediate the Transdermal Delivery of Bovine Serum Albumin(2013) Demir Y.K.; Akan Z.; Kerimoglu O.Background:The "poke and release" strategy for the delivery of macromolecules using polymeric microneedle (MN) is of great importance because it eliminates microneedle reuse, the risks of biohazardous sharps and cross contamination, and it requires no special disposal mechanism. The main objective of this study was the determination of the stability and delivery of bovine serum albumin (BSA) that was transported across human skin via sodium alginate (SA) microneedle arrays (MNs) and SA needle free patches using two different analytical methods.Methodology and Findings:The capability of two analytical methods, the bicinchoninic acid (BCA) assay and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), to precisely detect and quantify BSA within different types of polymeric MNs was assessed. The ex vivo protein release of BSA across dermatomed human abdominal skin from 10 w/w SA MNs was compared to that from needle-free patches using Franz diffusion cells. The developed applicator was mechanically characterized using a Texture Analyzer. The patch mold and its components were fabricated using a rapid prototyping machine.Conclusions/Significance:The BCA method was able to precisely detect BSA that had been loaded into SA MNs. However, the use of SDS-PAGE as the analytical method resulted in significantly different amounts of BSA recovered from differently conditioned polymeric MNs. The permeation of BSA across dermatomed human abdominal skin by SA MNs, which were composed of 100 pyramidal needles, increased by approximately 15.4 fold compared to the permeation obtained with SA needle-free patches. The ease of use of the applicator during the release studies was also demonstrated, as was its mechanical characterization. © 2013 Demir et al.Item The effect of bisphosphonates on bone mineral density in metastatic prostate cancer patients who are treated with anti-androgen drugs and radiotherapy(S. Karger AG, 2014) Karaköse A.; Yüksel M.B.; Aydoʇdu Ö.; Gümüş B.; Ateşçi Y.Z.; Akan Z.Objective: To evaluate the potential effect of bisphosphonates on bone mineral density (BMD) in patients who are treated with anti-androgen drugs and radiotherapy for metastatic prostate cancer.; Materials and Methods: The data of 31 patients with metastatic prostate cancer who were treated with anti-androgen drugs and radiotherapy during a 1-year period were retrospectively reviewed. Patients were divided in 2 groups, in which 17 patients in group 1 were treated with zoledronic acid (4 mg/month, intravenous) and 14 patients in group 2 who did not receive zoledronic acid. BMD was measured before the treatment and at the end of the 1st year by dual energy X-ray absorptiometry. Statistical analyses were performed with the T test.; Results: Mean age of the patients was 71.42 ± 6.7(range 59-85) years. A significant increase was noted for pelvic bone, femoral neck, and lumbar vertebrae t scores when pretreatment and 1st year measurements were compared in group 1 (p < 0.05). In group 2 a significant decrease was noted for pelvic bone and femoral neck t scores at the end of the 1st year (p < 0.05). A significant increase was noted for pelvic bone and femoral neck follow-up in BMD values at the end of the 1st year compared to initial measurements in group 1. A significant decrease was noted for lumbar vertebrae follow-up in BMD values at the end of the 1st year when compared to initial values in group 2.; Conclusion: Zoledronic acid significantly increases BMD and delays unfavorable outcomes for bones in men who are treated with anti-androgen drugs and radiotherapy for metastatic prostate cancer. Copyright © 2013 S. Karger AG, Basel.Item Environmental radioactivity and high incidence rates of stomach and esophagus cancer in the Van Lake Region: A causal relationship?(Asian Pacific Organization for Cancer Prevention, 2014) Akan Z.; Baskurt B.; Asliyuksek H.; Kam E.; Yilmaz A.; Yuksel M.B.; Biyik R.; Esen R.; Koca D.This study examined the incidence rates of cancer cases (averages for 2006-2010) and relationships with environmental radioactivity levels. Soil and water samples were collected from provincial and district centers of Van city and the outdoor gamma doses were determined using a portable gamma scintillation detector. Gross alpha and beta, (226)Ra, (232)Th, and (40)K activities were measured in both tap water and soil samples. Although high rates of stomach and esophagus cancers have been reported previously in Van the underlying reasons have not hitherto been defined. Incidences of cancers were highest in the Gurpinar (326.0) and Ozalp (377.1) counties (p<0.001). As to the results of the gross alpha and gross beta radioactivity measurements in the drinking water, these two counties also had high beta radionuclide levels: Gurpinar (140 mBq/dm3) and Ozalp (206 mBq/dm3). Even if within the normal range, a relation between the higher rate of the incidence of stomach and esophagus cancers with that of the higher rate of beta radionuclide activity was clear. On Spearman correlation analysis, the relation between higher beta radionuclide levels and cancer incidence was found to be statistically significant (p<0.01). According to the results of the analysis, Van residents receive an average 1.86 mSv/y annual dose from outdoor gamma radiation, ingestion of radionuclides in the drinking water, and indoor 222Rn activity. Moreover, gross alpha and beta activities were found to be extremely high in all of the lakes around the city of Van, Turkey. Further investigations with long-term detailed environmental radiation measurements are needed regarding the relationship between cancer cases and environmental radioactivity in the city of Van.Item Modification of the radial beam port of ITU TRIGA Mark II research reactor for BNCT applications(Elsevier Ltd, 2015) Akan Z.; Türkmen M.; Çakir T.; Reyhancan T.A.; Çolak T.; Okka M.; Kiziltaş S.This paper aims to describe the modification of the radial beam port of ITU (Istanbul Technical University) TRIGA Mark II research reactor for BNCT applications. Radial beam port is modified with Polyethylene and Cerrobend collimators. Neutron flux values are measured by neutron activation analysis (Au-Cd foils). Experimental results are verified with Monte Carlo results. The results of neutron/photon spectrum, thermal/epithermal neutron flux, fast group photon fluence and change of the neutron fluxes with the beam port length are presented. © 2015 Elsevier Ltd.Item Boron neutron capture therapy for breast cancer(Aras Part Medical International Press, 2015) Akan Z.[No abstract available]Item Montelukast is effective in preventing of ovarian hyperstimulation syndrome; an experimental study(Studio K Krzysztof Molenda, 2015) Eskicioğlu F.; Turan G.A.; Sivrikoz O.N.; Cengiz H.; Akan Z.; Şahin N.; Yilmaz O.; Yeşil H.; Vatansever S.Objectives: To determine the efficacy of montelukast in comparison with cabergoline in the prevention of ovarian hyperstimulation syndrome (OHSS) in rats. Material and methods: An experimental OHSS model was formed in 35 female Wistar rats. Rats (22 days old) were randomized into 5 groups, each containing 7 animals. The control group received no therapy; the mild OHSS group was administered pregnant mare serum gonadotropin (PMSG) 10 IU for 4 days, hCG 10 IU on the 5th day; the severe OHSS group received PMSG 10 IU for 4 days, hCG 30 IU on the 5th day. The montelukast group: received montelukast 10 mg/kg/day and the cabergoline group was administered cabergoline 100μg/kg/day via oral gavage for 6 days (days 22-27), in addition to those of severe OHSS. All groups were sacrificed on 28th day. Body weight, ovarian diameter and weight, vascular permeability, vascular endothelial growth factor (VEGF), semiquantitative VEGF receptor-1, and VEGF receptor-2 (VEGFR-2) immunohistochemistry were evaluated. Results: Ovarian diameter and VEGF expression were significantly lower in the montelukast and cabergoline groups than in the severe OHSS group. While montelukast was more effective in limiting vascular permeability in the severe OHSS, cabergoline was superior to montelukast with respect to the limiting effect on increased body weight and VEGFR-2 expression. Conclusions: The VEGF/VEGFR-2 interaction plays an important role in OHSS pathogenesis. Montelukast limits VEGF expression, and cabergoline reduces both VEGF and VEGFR-2 expressions; they are both effective therapies for the prevention of severe OHSS.Item Montelukast is effective in preventing of ovarian hyperstimulation syndrome; an experimental study(Studio K Krzysztof Molenda, 2015) Eskicioğlu F.; Turan G.A.; Sivrikoz O.N.; Cengiz H.; Akan Z.; Sahin N.; Yilmaz O.; Yesil H.; Vatansever S.Objectives: To determine the efficacy of montelukast in comparison with cabergoline in the prevention of ovarian hyperstimulation syndrome (OHSS) in rats. Material and methods: An experimental OHSS model was formed in 35 female Wistar rats. Rats (22 days old) were randomized into 5 groups, each containing 7 animals. The control group received no therapy; the mild OHSS group was administered pregnant mare serum gonadotropin (PMSG) 10 IU for 4 days, hCG 10 IU on the 5th day; the severe OHSS group received PMSG 10 IU for 4 days, hCG 30 IU on the 5th day. The montelukast group: received montelukast 10 mg/kg/day and the cabergoline group was administered cabergoline 100μg/kg/day via oral gavage for 6 days (days 22-27), in addition to those of severe OHSS. All groups were sacrificed on 28th day. Body weight, ovarian diameter and weight, vascular permeability, vascular endothelial growth factor (VEGF), semiquantitative VEGF receptor-1, and VEGF receptor-2 (VEGFR-2) immunohistochemistry were evaluated. Results: Ovarian diameter and VEGF expression were significantly lower in the montelukast and cabergoline groups than in the severe OHSS group. While montelukast was more effective in limiting vascular permeability in the severe OHSS, cabergoline was superior to montelukast with respect to the limiting effect on increased body weight and VEGFR-2 expression. Conclusions: The VEGF/VEGFR-2 interaction plays an important role in OHSS pathogenesis. Montelukast limits VEGF expression, and cabergoline reduces both VEGF and VEGFR-2 expressions; they are both effective therapies for the prevention of severe OHSS. © Polskie Towarzystwo Ginekologiczne.Item The association of HLA-G and immune markers in recurrent miscarriages(Taylor and Francis Ltd, 2016) Eskicioğlu F.; Özdemir A.T.; Özdemir R.B.; Turan G.A.; Akan Z.; Hasdemir S.P.Objective: To determine role of human leukocyte antigen (HLA)-G, CD8, CD16, CD56, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α for recurrent miscarriages in feto–maternal interface. Method: Chorion and decidua samples were obtained from 11 women with unwanted pregnancies (healthy pregnancy, HP) and 10 women with missed abortion diagnosis after at least two pregnancy losses (recurrent miscarriage, RM). In addition, endometrial tissues were obtained from 10 non-pregnant women (NonP). The expressions of markers were evaluated using the Western blot analysis. The values obtained between different groups were compared. Results: The highest protein expression of CD56 was found in the HP compared to NonP and RM. Meanwhile, the lowest protein expression of CD16 was observed in the NonP compared to HP and RM. The HLA-G expression exhibited the highest level in HP; however, there was no statistically significant difference between groups. CD8 and IFNγ expressions were lowest in the NonP group; however, TNF-α was highest in the RM group. Conclusions: The CD56 expression of uterine NK cells may be an indicator of a HP. However, not statistically significant, the increased expression of CD16, CD8, and also significantly increased expression of TNF may be associated with the predominant cytotoxic activity in the maternal immune system in patients with RM. Although there was no change in the expression of HLA-G, this finding may mean that the maternal immune system is unresponsive to HLA-G-mediated immunosuppressive signals originating from the fetus in these cases. © 2015 Taylor & Francis.