Erkan Rayaman

Marmara University, İstanbul, Istanbul, Turkey

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Publications (8)6.8 Total impact

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    Timucin Ugurlu, Erkan Rayaman, Ugur Karacicek
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    ABSTRACT: The oral route is the most preferred form of drug administration for systemic action, having a high degree of patient compliance (1) and ease of use. However, oral route has several physiological difficulties such as variable nature of gastric empty-ing system, inability to localize the drug delivery system (DDS) in desired regions of the gastro-intes-tinal system (GIS), shorter residence time and incomplete drug release of DDS (2). As a result of above factors, a shorter residence time and incom-plete drug release leads to unpredictable bioavail-ability of DDS. Thus, control of the placement for DDS in a specific part of GIS according to absorp-tion window may increase gastric residence time and bioavailability of DDS by preventing drug release from reaching desired absorption site of GIS (3). There have been several systems developed by researchers to increase the retention time of a DDS in the stomach (2). The examples of these are float-ing systems (4), swelling and expanding systems (5, 6), modified-shape systems (5ñ7), high density sys-tems (8), and other delayed gastric emptying devices (2, 9). The floating drug delivery system is used commonly among these delivery systems. Helicobacter pylori was discovered in 1984 (10) and then it has been considered to be the most frequent bacterial infection worldwide to cause ulcer disease, gastric cancer and MALT-lymphoma (11). Complete eradication canít be achieved due to insuf-ficient amount of antibiotics in gastric mucosa and short residence time of DDSís (12). Thus, eradica-tion of H. pylori requires high concentration of antibiotics in gastric mucosa and availability of DDS in stomach for longer durations. CLA is a semi-synthetic antimicrobial macro-lide antibiotic, which was discovered and patented by Taisho Pharmaceutical Co. Ltd. Japan in 1980 (12). CLA is the most preferred molecule, due to the lowest MIC value, proper pharmacokinetic proper-ties and high efficiency on monotherapy of H. pylori (12). Moreover, CLA is stable in gastric environ-ment and pH, and further (13), it has short half-life (14). Above properties of CLA make it a proper can-didate for modified release drug delivery systems for the treatment of H. pylori. Traditional drug development strategies require more runs of experiments, time and money to achieve desired product quality while providing
    Acta poloniae pharmaceutica. 03/2014; 71(2).
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    Nobel medicus 04/2013; 9(1):81-88. · 0.04 Impact Factor
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    ABSTRACT: To investigate the effects of Nigella sativa seed supplementation on symptom levels, polymorphonuclear leukocyte (PMN) functions, lymphocyte subsets and hematological parameters of allergic rhinitis. Twenty-four patients randomly selected from an experimental group of 31 (mean age 34 years) sensitive to house dust mites with allergic rhinitis and a control group of 8 healthy volunteers (mean age 23 years) were treated with allergen-specific immunotherapy in conventional doses for 30 days. After a month of immunotherapy, 12 of the 24 patients and the 8 healthy volunteers were given N. sativa seed supplementation (2 g/day orally) for 30 days. The remaining 12 patients continued only on immunotherapy during the same period. The other 7 patients were given 0.1 ml saline solution subcutaneously once a week as a placebo. The symptom scores, PMN functions, lymphocyte subsets and other hematological parameters were evaluated before and after all treatment periods. There was a statistically significant increase in the phagocytic and intracellular killing activities of PMNs of patients receiving specific immunotherapy, especially after the addition of N. sativa seed. The CD8 counts of patients receiving specific immunotherapy plus N. sativa seed supplementation significantly increased compared to patients receiving only specific immunotherapy. PMN functions of healthy volunteers significantly increased after N. sativa seed supplementation compared to baseline. N. sativa seed supplementation during specific immunotherapy of allergic rhinitis may be considered a potential adjuvant therapy.
    Medical Principles and Practice 01/2010; 19(3):206-11. · 0.96 Impact Factor
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    ABSTRACT: Today new antibuberculous drugs and new combination regiments have been devevoped against the tuberculous resistance. However, the effects of these drugs on the immune system of the host has not been known yet. The aim of this study was to investigate the in vitro effects of primary antituberculous drugs [isoniazid (INH, 5jug/ml), rifampicine (RIF, 7jug/ml), pyrazinamide (PZA, 40jug/ml), ethambutol (EMB, 7jug/ml), streptomycine (S, 25jug/ml)J, secondary antituberculous drugs [amikacin (A, 24jug/ml), ofloxacin (OFLX, 2,9jug/ml), cyclocerine (CYC, lOjug/ml), para-aminosalicilic acid (PAS, 90jug/ml), prothionamide (PTH, l,6jug/ml), levofloxacin (LVFX, 2,8jug/ml)J and their combinations at therapeutic concentrations on polymorphonuclear leukocyte (PMN) functions (phagocytic and intracellular killing activity) of 15 healthy young volunteers, whose average age was 25. PMNs were isolated by ficoll-hypaque gradient centrifugation method from venous blood with EDTA (O.lg/ml). Phagocytosis and intracellular killing activity were assayed by modifying Alexander's method. A and PAS, which are secondary drugs that significantly increased the phagocytic activity, OFLX significantly increased the intracellular killing activity when compared with the control(drug-free) (p<0.05). The other primary and secondary drugs and their combinations did not significantly affect the phagocytic and intracellular killing activity when compared with the control(drug-free) (p>0.05). As a conclusion, the use of antituberculous drugs and their combinations whose possitive effects are known not only on the microorganism but also on the immune system maybe useful in the treatment of patients with tuberculosis by showing stimulatory effect on PMN functions .
    Turk J. Pharm. Sci. 01/2008; 5:117-128.
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    ABSTRACT: The effects of ciprofloxacin, cefodizime, rifampicine, doxycycline and cefodizime + rifampicine combination on polymorphonuclear leukocyte (PMN) functions (phagocytosis and intracellular killing activity) were investigated in vitro in elderly patients and compared with those of healthy young volunteers before and after zinc supplementation. PMNs of 13 elderly hypertensive patients and 10 healthy young volunteers were isolated by Ficoll-Hypaque gradient centrifugation method from venous blood with EDTA. The subjects were given 22 mg/daily/oral zinc supplementation for 1 month. Serum zinc levels before and after supplementation were measured by flame atomic absorbtion spectrophotometer and the effects of each drug on PMN functions at therapeutic concentrations were investigated. Ciprofloxacin significantly increased the PMN's phagocytic activity of elderly patients (p = 0.002) before zinc supplementation and significantly increased both PMN functions of elderly patients (p = 0.002) after zinc supplementation. The same antibiotic significantly increased both PMN functions of healthy young volunteers (p = 0.005 and p<0.05, respectively) before and after zinc supplementation when compared with the control (drug-free). Cefodizime significantly increased the PMN's phagocytic activity of elderly patients (p = 0.003, p = 0.002) before and after zinc supplementation when compared with the control (drug-free). It also significantly increased both PMN functions of healthy young volunteers (p = 0.005 and p<0.05, respectively) before and after zinc supplementation when compared with the control (drug-free). Doxycycline significantly increased PMN's intracellular killing activity of healthy young volunteers before zinc supplementation (p<0.05) when compared with the control (drug-free) values. Rifampicine significantly decreased PMN's phagocytic activity of elderly patients (p<0.05) after zinc supplementation. Cefodizime+rifampicine combination significantly increased PMN's phagocytic activity at therapeutic concentrations of healthy young volunteers (p = 0.005) before zinc supplementation and PMN's phagocytic activity of elderly patients (p<0.05) after zinc supplementation when compared with the control (drug-free). Consequently, in the present study from the antibiotics ciprofloxacin, cefodizime and cefodizime + rifampicine combination, which are accepted as biological response modifiers have demonstrated stimulatory effects by significantly increasing polymorphonuclear leucocyte functions (phagocytosis and/or intracellular killing activity) of elderly patients and healthy young volunteers in vitro before and after zinc supplementation. Additionally zinc supplementation has more immunostimulatory effects on PMN functions of healthy young volunteers than elderly patients.
    International Immunopharmacology 05/2006; 6(5):808-16. · 2.42 Impact Factor
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    ABSTRACT: Immunotherapy plays an important role in the therapy of allergic rhinitis and bronchial asthma. However, there is not much information about the effects of allergen-specific immunotherapy (SIT) on the polymorphonuclear leukocyte functions. The aim of this study was to investigate the effects of specific immunotherapy on phagocytic and intracellular killing activities of polymorphonuclear leukocytes (PMN) derived from patients with seasonal allergic rhinitis. Twenty-four patients with seasonal allergic rhinitis documented to be sensitive to grass pollen were included in this study. Patients were divided into 3 groups. Group 1 (n=7) received conventional immunotherapy whereas patients in Group 2 (n=7) were treated with short-term immunotherapy and the third group (n=10) were given placebo during the study process. Both phagocytic and intracellular killing activities were significantly increased (p=0.002, p<0.0001, respectively) by conventional immunotherapy when compared to the first determination. In the short-term immunotherapy group, phagocytic activity was increased very significantly (p=0.0001), whereas intracellular killing activity was not affected (p=0.252). There were no changes in these parameters in the placebo group. These results suggest that allergen-specific immunotherapy has an enhancing effect on PMNs functions in the patients with seasonal allergic rhinitis. It should be clarified by further studies whether this enhancement might be considered as another beneficial effect of the immunotherapy.
    International Immunopharmacology 05/2005; 5(4):661-6. · 2.42 Impact Factor
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    ABSTRACT: To compare the polymorphonuclear leukocyte (PMN) functions (phagocytosis and intracellular killing activity) of elderly patients with healthy young volunteers. Fifty-nine elderly patients who had various diseases (cancer, hypertension and diabetes mellitus, DM) and 10 healthy young volunteers were included in this study. Ficoll-Hypaque gradient centrifugation was used to isolate PMNs from venous blood containing EDTA (0.1 g/ml). Phagocytosis and intracellular killing activity of neutrophils were assayed using a modification of Alexander's method, in which serum opsonins, number of neutrophils and number of microorganisms are standardized in order to detect both increases and decreases in phagocytosis and intracellular killing as well as combined abnormalities of these two functions. The least significant difference test was used to compare the results in the two groups. Phagocytic activity of PMNs from patients with cancer was significantly higher than that of healthy young volunteers (p < 0.05) and elderly patients with hypertension and DM (p < 0.05). There was no statistical difference between the phagocytic activity of PMNs from elderly patients with hypertension and DM and healthy young volunteers (p > 0.05). The intracellular killing activity of PMNs from elderly patients with hypertension, DM and cancer was significantly lower than that of healthy young volunteers (p = 0.001, p < 0.0001, p = 0.003, respectively). The intracellular killing activity of PMNs from elderly patients was significantly decreased when compared with that of healthy young volunteers. Ageing, chronic diseases and drugs used in the treatment of these elderly patients may be the cause for decreased intracellular killing activity.
    Medical Principles and Practice 01/2005; 14(6):382-5. · 0.96 Impact Factor
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    ABSTRACT: In this study the in vitro effects of imipenem, cefodizime, vancomycin, teicoplanin, imipenem- amikacin, imipenem-teicoplanin combinations and vitamin A at therapeutic concentration on phagocytic and intracellular killing activity of polymorphonuclear leukocytes (PMNs) in neutropenic children with acute leukemia were investigated. Twenty-one neutropenic children with mean age 7 were included in this study and were clinically divided in 3 groups. The first group included 7 nonfebrile neutropenic children not receiving chemotherapy; the second group included 7 febrile neutropenic children receiving chemotherapy; the third group included 7 nonfebrile neutropenic children receiving chemotherapy. PMNs were isolated by Ficoll-Hypaque gradient centrifugation method. C. albicans ATCC 10231 was used to measure the phagocytosis and intracellular killing activity of PMNs. Consequently, in the 1st group; the antibiotics used in our investigation and vitamin A significantly increased PMN's phagocytic activity, cefodizime showed immunomodulatory effect on the both PMN functions in the 1st and 2st group. Additionally, vancomycin had immunomodulatory effect on the both PMN functions in the 1st group and only on the phagocytic activity in 3rd group.

Publication Stats

23 Citations
6.80 Total Impact Points

Institutions

  • 2005–2013
    • Marmara University
      • • Department of Pharmaceutical Microbiology
      • • Faculty of Pharmacy
      İstanbul, Istanbul, Turkey