Hakan Goker
Hacettepe University
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Publication
Featured researches published by Hakan Goker.
Journal of International Medical Research | 2008
Hakan Goker; Ibrahim C. Haznedaroglu; Sevil Ercetin; Serafettin Kirazli; Umit Akman; Yusuf Ozturk; Huseyin Cahit Firat
Ankaferd Blood Stopper® (ABS), a standardized mixture of five plants, has been used historically as a haemostatic agent but its mechanism of action remains unknown. This study investigated the in vitro effects of ABS on haemostatic parameters. When added to plasma or serum, ABS induced the very rapid formation of a protein network and erythrocyte aggregation. The levels of coagulation factors II, V, VII, VIII, IX, X, XI, and XIII were not affected by ABS. Plasma fibrinogen activity and antigen levels were decreased following the addition of ABS, in parallel with the prolonged thrombin time. Total protein, albumin, and globulin levels decreased after the addition of ABS. Our findings suggest that ABS stimulates the formation of an encapsulated protein network that provides focal points for erythrocyte aggregation. ABS has the therapeutic potential to be used for the management of haemorrhage and this agent should be investigated further in clinical trials.
Bioorganic & Medicinal Chemistry | 2002
Hakan Goker; Canan Kus; David W. Boykin; Sulhiye Yıldız; Nurten Altanlar
New 2-substituted-phenyl-1H-benzimidazole-5-carboxylic acids (35, 38), ethyl-5-carboxylate (36), -5-carboxamides (37, 39),-5-carboxaldehyde (42), -5-chloro (40), -5-trifluoromethyl (41), and -5-carbonitriles (44-53, 55-67), -6-carbonitrile (54) were prepared and evaluated in vitro against Candida species. The cyano substituted compounds 53, 57, 58 and 61 exhibited the greatest activity with MIC values of 3.12 microg/mL, values similar to that of fluconazole.
European Journal of Haematology | 2011
Meral Beksac; Rauf Haznedar; Tulin Firatli-Tuglular; Hakan Ozdogu; Ismet Aydogdu; Nahide Konuk; Gülsan Türköz Sucak; Isik Kaygusuz; Sema Karakus; Emin Kaya; Ridvan Ali; Zafer Gulbas; Gülsüm Özet; Hakan Goker; Levent Undar
The combination of melphalan–prednisone–thalidomide (MPT) has been investigated in several clinical studies that differed significantly with regard to patient characteristics and treatment schedules. This prospective trial differs from previous melphalan–prednisone (MP) vs. MPT trials by treatment dosing, duration, routine anticoagulation, and permission for a crossover. Newly diagnosed patients with multiple myeloma (MM) (n = 122) aged greater than 55 yr, not eligible for transplantation were randomized to receive 8 cycles of M (9 mg/m2/d) and P (60 mg/m2/d) for 4 d every 6 wk (n = 62) or MP and thalidomide (100 mg/d) continuously (n = 60). Primary endpoint was treatment response and toxicities following 4 and 8 cycles of therapy. Secondary endpoints were disease‐free (DFS) and overall survival (OS). Overall, MPT‐treated patients were younger (median 69 yr vs. 72 yr; P = 0.016) and had a higher incidence of renal impairment (RI, 19% vs. 7%, respectively; P = 0.057). After 4 cycles of treatment (n = 115), there were more partial responses or better in the MPT arm than in the MP arm (57.9% vs. 37.5%; P = 0.030). However, DFS and OS were not significantly different between the arms after a median of 23 months follow‐up (median OS 26.0 vs. 28.0 months, P = 0.655; DFS 21.0 vs. 14.0 months, P = 0.342, respectively). Crossover to MPT was required in 11 patients, 57% of whom responded to treatment. A higher rate of grade 3–4 infections was observed in the MPT arm compared with the MP arm (22.4% vs. 7.0%; P = 0.033). However, none of these infections were associated with febrile neutropenia. Death within the first 3 months was observed more frequently in the MP arm (n = 8, 14.0%) than in the MPT arm (n = 2, 3.4%; P = 0.053). Long‐term discontinuation and dose reduction rates were also analyzed (MPT: 15.5% vs. MP: 5.3%; P = 0.072). Although patients treated with MPT were relatively younger and had more frequent RI, better responses and less early mortality were observed in all age groups despite more frequent discontinuation. This study is registered at http://www.clinicaltrials.gov as #NCT00934154.
Clinical and Applied Thrombosis-Hemostasis | 2009
Handan Cipil; Ali Kosar; Arif Kaya; Burak Uz; Ibrahim C. Haznedaroglu; Hakan Goker; Oktay Özdemir; Mustafa Koroglu; Serafettin Kirazli; Huseyin Cahit Firat
Aim: Ankaferd comprises a mixture of Thymus vulgaris, Glycyrrhiza glabra, Vitis vinifera, Alpinia officinarum and Urtica dioica. Ankaferd Blood Stopper (ABS) has been approved in the management of bleedings. This study aimed to evaluate in vivo hemostatic effect of ABS in rats pretreated with warfarin. Materials and methods: Wistar rats (210-270 g) were treated either with warfarin (2 mg/kg) or vehicle (0.9% NaCl) orally before bilateral hind leg amputation. ABS was administered topically to one of the amputed legs. The duration of bleeding and the amount of bleeding were measured to evaluate the hemostatic effect of ABS. Results: Topical ABS administration to amputed leg shortened the duration of bleeding markedly in both untreated and warfarin-treated rats by 31.9% [1.42 min (95% CI: 0.35-2.49)] and 43.5% [5.12 min (95% CI: 2.16-8.07)] respectively. The amount of bleeding in ABS-administered amputed leg showed a decrease by 53.8% in warfarin-treated group. Conclusions: ABS has in vivo hemostatic actions that may provide a therapeutic potential for the management of patients with deficient primary hemostasis in clinical medicine.
Medical Principles and Practice | 2009
Hasan Bilgili; Ali Kosar; Mevlut Kurt; Ibrahim Koral Onal; Hakan Goker; Ozge Captug; Ali Shorbagi; Mehmet Turgut; Murat Kekilli; Ozlem Kar Kurt; Serafettin Kirazli; Salih Aksu; Ibrahim C. Haznedaroglu
Objective: The purpose of this study was to show the hemostatic effect of spray, solution and tampon forms of Ankaferd Blood Stopper® (ABS), a unique medicinal plant extract historically used as a hemostatic agent in Turkish folklore medicine, in a porcine bleeding model. Materials and Methods: Two 1-year-old pigs were used as bleeding models for superficial and deep skin lacerations, grade II liver and spleen injuries, grade II saphenous vein injury and grade IV saphenous artery injury. Spray, solution or tampon forms of ABS were applied after continuing bleeding was confirmed. The primary outcome was time to hemostasis. Volume of blood loss was not measured. The pigs were euthanized at the end of the experiment. Results: Spray or direct application of ABS solution resulted in instant control of bleeding in superficial and deep skin lacerations as well as puncture wounds of the liver. A 40-second application of ABS tampon was sufficient to stop bleeding of skin lacerations, while 1.5- and 3.5-min applications were used to control hemorrhage from the saphenous vein and artery, respectively. No rebleeding was observed once hemostasis was achieved. However, repeated applications of ABS solution and tampon were only temporarily effective in the hemostasis of spleen injury. Conclusions: The data showed that ABS was an effective hemostatic agent for superficial and deep skin lacerations and minor/moderate trauma injuries in a porcine bleeding model.
Clinical and Applied Thrombosis-Hemostasis | 2010
Berat Z. Haznedaroglu; Ibrahim C. Haznedaroglu; Sharon L. Walker; Hasan Bilgili; Hakan Goker; Ali Kosar; Alper Aktas; Ozge Captug; Mevlut Kurt; Oktay Özdemir; Serafettin Kirazli; Huseyin Cahit Firat
Ultrastructural and morphological analyses of a novel hemostatic agent, Ankaferd Blood Stopper (ABS), in comparison to its in vitro and in vivo hemostatic effects were investigated. High-resolution scanning electron microscopy (SEM) images accompanied with morphological analysis after topical application of ABS revealed a very rapid (<1 second) protein network formation within concurrent vital erythroid aggregation covering the classical coagulation cascade. Histopathological examination revealed similar in vivo ABSinduced hemostatic network at the porcine hepatic tissue injury model. Instantaneous control of bleeding was achieved in human surgery-induced dental tissue injury associated with primary and secondary hemostatic abnormalities. Ankaferd Blood Stopper could hold a great premise for clinical management of surgery bleedings as well as immediate cessation of bleeding on external injuries based on upcoming clinical trials.
Blood Coagulation & Fibrinolysis | 2009
Ali Kosar; Handan Cipil; Arif Kaya; Burak Uz; Ibrahim C. Haznedaroglu; Hakan Goker; Oktay Özdemir; Sevil Ercetin; Serafettin Kirazli; Huseyin Cahit Firat
Ankaferd comprises a standardized mixture of plants Thymus vulgaris, Glycyrrhiza glabra, Vitis vinifera, Alpinia officinarum and Urtica dioica. Ankaferd Blood Stopper (ABS) as a medicinal product has been approved in the management of external hemorrhage and dental surgery bleedings in Turkey. This study aimed to evaluate the in-vivo hemostatic effect of ABS in rats pretreated with acetylsalicylic acid or enoxaparin. Wistar rats (210–270 g) of both sexes were used in this study. The animals were pretreated with acetylsalicylic acid (10 mg/kg) orally for 4 days or enoxaparin sodium (8 mg/kg) subcutaneously for 3 days or did not receive any anticoagulant before tail cut at 4th day. ABS was administered topically [a total of 4 ml (1 ml/puff × 4)] to the cut tail in the studied animals. The duration of bleeding and the amount of bleeding were measured in order to evaluate the hemostatic effect of ABS. In acetylsalicylic acid-treated animals, topical ABS reduced both the duration and also the amount of bleeding volume by 68.4 and 54.6%, respectively. It was also effective in shortening the duration of bleeding (30.6%) and decreasing the amount of bleeding (32.8%) in enoxaparin-treated animals. ABS, a traditional folkloric medicinal plant extract, has in-vivo hemostatic actions, which may provide a therapeutic potential for the management of patients with deficient hemostasis in the clinical medicine.
Antimicrobial Agents and Chemotherapy | 2003
M. Daniel Givens; Christine C. Dykstra; Kenny V. Brock; D.A. Stringfellow; Arvind Kumar; Chad E. Stephens; Hakan Goker; David W. Boykin
ABSTRACT Bovine viral diarrhea virus (BVDV) is an economically significant pathogen of cattle and a problematic contaminant in the laboratory. BVDV is often used as an in vitro model for hepatitis C virus during drug discovery efforts. Aromatic dicationic molecules have exhibited inhibitory activity against several RNA viruses. Thus, the purpose of this research was to develop and apply a method for screening the aromatic cationic compounds for in vitro cytotoxicity and activity against a noncytopathic strain of BVDV. The screening method evaluated the concentration of BVDV in medium and cell lysates after 72 h of cell culture in the presence of either a 25 or 5 μM concentration of the test compound. Five of 93 screened compounds were selected for further determination of inhibitory (90 and 50%) and cytotoxic (50 and 10%) concentration endpoints. The screening method identified compounds that exhibited inhibition of BVDV at nanomolar concentrations while exhibiting no cytotoxicity at 25 μM concentrations. The leading compounds require further investigation to determine their mechanism of action, in vivo activity, and specific activity against hepatitis C virus.
Clinical and Applied Thrombosis-Hemostasis | 2010
Hasan Bilgili; Ozge Captug; Ali Kosar; Mevlut Kurt; Murat Kekilli; Ali Shorbagi; Ozlem Kar Kurt; Oktay Özdemir; Hakan Goker; Ibrahim C. Haznedaroglu
Background: Ankaferd blood stopper (ABS) is a standardized herbal extract obtained from 5 different plants. In Turkey, it has been approved for local topical applications in external postsurgical and postdental surgery bleedings. Ankaferd blood stopper, besides its hemostatic activity, has in vitro anti-infectious and antineoplastic actions. Objective: The aim of this study was to assess short-term hematological and biochemical safety following the oral systemic administration of ABS to rabbits. Methods: Twelve rabbits (aged 6-12 months) were included to test the safety of oral ABS. Animals were divided into 4 groups, which had ABS administered orally at doses of 1, 3, 6, and 9 mL, irrespective of their weight. The general well-being and feeding patterns of the animals were observed for a period of 7 days. Blood samples (5.5 mL) were obtained just before oral administration, on days 1 and 4. Results: During the observation period of 7 days, none of the animals showed any abnormal behavior or deviation from the normal. Acute mucosal toxicity, hematotoxicity, hepatotoxicity, nephrotoxicity, and biochemical toxicity were not observed during the short-term follow-up of the animals. Conclusions: No signs of toxicity were observed in rabbits during short-term study with oral ABS administration.
Molecules | 2005
Hakan Goker; Mehmet Alp; Sulhiye Yıldız
A series of 22 novel 1,2-disubstituted-1H-benzimidazole-N-alkylated-5-carboxamidine derivatives were synthesized and evaluated for in vitro antibacterial activity against S. aureus and methicillin resistant S. aureus (MRSA), E. coli, E. faecalis and for antifungal activity against C. albicans. Compound 59 [1-(2,4-dichlorobenzyl)-N-(2-diethylaminoethyl)-1H-benzimidazole-5-carboxamidine], with a 3,4-dichlorophenyl group at the C-2 position, displayed the greatest activity (MIC = 3.12 μg/mL against both some bacteria and the fungus C. albicans).