Browsing by Author "Demir, A."

Now showing 1 - 5 of 5

Cancer Stem Cells and Nitric Oxide
(Elsevier, 2023) Taskiran, A.; Demir, A.; Acikgoz, E.; Oktem, G.
Cancer stem cells (CSCs) forming the tumor heterogeneity are thought to be the main reason for ineffective and insufficient conventional cancer treatments including surgery, radiotherapy, and chemotherapy and, therefore, causing relapse, metastasis, and multidrug resistance in the long term. CSCs express specific biomarkers on their surface and, thus, differentiate from non-CSCs. The metabolic and signaling activities of CSCs have been shown to be different from those of non-CSCs, and there are still many unknown activities. CSCs share Wnt, Hedgehog, and Notch signaling pathways and many surface markers with embryonic and adult stem cells, indicating that CSCs are the starting point of tumor formation. Deregulation of intrinsic and extrinsic factors of cells induces altered metabolic activities, including the nitric oxide (NO) metabolism, that have a crucial role in the cell fate. CSCs produce high levels of NO and secrete it in the tumor microenvironment involving a wide range of components such as stromal cells, cancer-associated fibroblasts (CAFs), immune cells, nonimmune cells, and blood vessels. Studies have shown that cancer (stem) cell-derived NO promotes chronic inflammation in the tumor microenvironment, pro-tumorigenic activities of CAFs, drug resistance, invasion, and metastasis. These events are reversible by inhibiting cellular NO by NO-releasing drugs or NO donors in cancer therapy either alone or combined with other cytotoxic drugs. Thereby, NO is suggested to be a promising agent for cancer therapy, prevention of the metastatic cascade, and CSC transformation. Further research is needed to elucidate the highly sophisticated activities of NO and CSCs for the advancements of new therapeutic strategies targeting CSCs. © 2023 Elsevier Inc. All rights reserved.
Effect of Urtica Dioica Seed Extract on Aquaporin 1 and 7, Caspase-3 and Oxidant/Antioxidant Status in Diethylnitrosamine-Induced Kidney Damage in Rats
(Yuzuncu Yil Universitesi Tip Fakultesi, 2024) Keleş, Ö.F.; Huyut, Z.; Yıldızhan, K.; Demir, A.
Diethylnitrosamine (DENA) is known to have a carcinogenic effect on the liver by stimulating oxid ative stress and inflammation. There are few studies on the negative effects of DENA on kidney tissue, and the therapeutic effect of Urtica dioica Seed Extract (UDSE) against the negative effects of DENA is investigated for the first time in this study. Th is study investigated the protective effect of UDSE on kidney tissues of rats administered DENA. The rats were divided into four groups (n=8): control, UDSE (1 mL/kg/daily for 16 weeks), DENA (200 mg/kg/first day), DENA+UDSE (200 mg/kg/first-day single dose, and 1 mL/kg/daily for 16 weeks). At the end of the experiment, blood and kidney tissues were taken for biochemical and pathological analysis. DENA administration has been shown to increase oxidative stress in the kidneys and reduce antioxidant levels. Moreover, compared to the DENA group, DENA decreased the level of aquaporin (AQP)-1 in kidney tissue, while UDSE treatment increased both AQP-1 levels in kidney tissue and AQP-1 and 7 levels in the serum samples. Histopathological examination of the kidney revealed significant coagulation necrosis, especially in proximal tubular epithelial cells, hyperemia in capillaries, mononuclear cell infiltration between tubular area s, atrophy in the glomerular cluster, and adhesions with Bowman's capsule. In addition, there was a decrease in both caspase-3 (immunohistochemically) expression and TOS levels in the DENA+UDSE group compared to the DENA group, while an increase was seen in antioxidant levels. These findings indicated that UDSE may be an essential therapeutic agent against DENA-induced kidney injury. © 2024, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.
Gasless Vs Gaseous Laparoscopy in the Treatment of Hepatic Hydatid Disease
(Springer New York, 1999) Berberoǧlu, M.; Taner, S.; Dilek, O.N.; Demir, A.; Sari, S.
Background: Despite the reduced rate of occurrence, the hydatidosis of the liver is still taking an important place in surgical practice in Asia Minor and the Middle East. Traditional techniques for performing liver cyst surgery seem to be comparatively traumatic. In this clinical study, we present our experience with laparoscopic treatment of hydatid cyst of the liver and discuss the validity of the gasless technique as a solution to carbon dioxide (CO2) ensufflation problems. Methods: All patients were prepared by administrating albendazole for 21 days preoperatively. Surgery was performed on 87 patients under general anesthesia. Working space was obtained in 51 operations by using an abdominal wall lifting device, Laparolift(TM) (Origin Med Systems, Menlo Park, California, USA) (group 1). In 36 patients, the abdominal cavity was insufflated with CO2 gas (group 2). In all cases, hydatid cysts were identified, and gauses soaked in germicide solution were placed around them. The cysts were punctured and aspirated. Then germisid solution was injected into the cysts. The cysts walls were opened, and germinative membranes were evacuated. Results: The median operation time was 50.49 ± 10.9 min (range, 30-75 min) in group 1 and 70.8 ± 16 min (ranges 40-120 min) in group 2. The difference in the operative times of the two groups was significant (p < 0.01). There was no significant difference between the minor complications of the two groups. There were no deaths and no major complications or conversions to open surgery in any of the groups. There were no recurrences during follow-up time. Conclusions: The use of gasless technique for the laparoscopic treatment of liver cyst is a safe, time-saving, and promising procedure that can be applied in selected cases.
Modeling of the Angle of Shearing Resistance of Soils Using Soft Computing Systems
(Pergamon-elsevier Science Ltd, 2009) Kayadelen, C.; Gunaydin, O.; Fener, M.; Demir, A.; Ozvan, A.
Precise determination of the effective angle of shearing resistance (phi') value is a major concern and an essential criterion in the design process of the geotechnical structures, such as foundations, embankments, roads, slopes, excavation and liner systems for the solid waste. The experimental determination of phi' is often very difficult, expensive and requires extreme cautions and labor. Therefore many statistical and numerical modeling techniques have been suggested for the phi' value. However they can only consider no more than one parameter, in a simplified manner and do not provide consistent accurate prediction of the phi' value. This study explores the potential of Genetic Expression Programming, Artificial Neural Network (ANN) and Adaptive Neuro Fuzzy (ANFIS) computing paradigm in the prediction of phi' value of soils. The data from consolidated-drained triaxial tests (CID) conducted in this study and the different project in Turkey and literature were used for training and testing of the models. Four basic physical properties of soils that cover the percentage of fine grained (FG), the percentage of coarse grained (CG), liquid limit (LL) and bulk density (BD) were presented to the models as input parameters. The performance of models was comprehensively evaluated some statistical criteria. The results revealed that GEP model is fairly promising approach for the prediction of angle of shearing resistance of soils. The statistical performance evaluations showed that the GEP model significantly outperforms the ANN and ANFIS models in the sense of training performances and prediction accuracies. (C) 2009 Elsevier Ltd. All rights reserved.
Tubeless Percutaneous Nephrolithotomy: Can Be a Choice, Why Not
(Bentham Science Publishers B.V., 2014) Karadag, M.A.; Cecen, K.; Demir, A.; Kocaaslan, R.; Taken, K.; Altunrende, F.
Percutaneous nephrolithotomy (PCNL) has been widely accepted and is commonly used to treat renal calculi. The optimal drainage of kidney after PCNL has not been clearly determined yet. Placement of an 18F to 24F nephrostomy tube at the end of the procedure is accepted as standard of care to date. The main advantages are adequate renal drainage, hemostatic tamponade and providing renal access for second look PCNL. However, based on the concept that the purpose of the tube is only to maintain adequate drainage of the kidney, a "tubeless" approach has been developed by placing a ureteral stent or catheter to provide drainage after PCNL instead of a nephrostomy tube. Tubeless PCNL is an effective and safe procedure for treatment of renal stones in selected cases. This procedure can even be chosen for patients with previous renal surgery, and hemorrhagic tendency. By using this method, less postoperative pain and a shorter hospital stay can be achieved, when compared with conventional PCNL. There is a controversy over ideal drainage system after PCNL in recent years. Herein, we made a systematic review for efficacy and safety of tubeless PCNL, totally tubeless PCNL, discussed different variations and compared the outcomes of this technique with standart PCNL. © Karadag et al.; Licensee Bentham Open.