Erkan Rayaman

Marmara University, İstanbul, Istanbul, Turkey

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Publications (15)10.99 Total impact

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    ABSTRACT: Encapsulation of vancomycin (VANCO) into biodegradable levan microparticles was achieved using a simple preparation technique. Microparticles were prepared by using levan polysaccharide produced by a halophilic bacterium Halomonas smyrnensis AAD6(T). To optimize efficiency of encapsulation process by precipitation method, three parameters were studied: drug and polymer concentrations and preparation rotating speed. The particles were characterized in vitro. The size of levan microparticles was changed between 0.404 μm and 1.276 μm. The surface charge was detected between +4.1 mV and +6.5 mV. The highest drug encapsulation capacity of the system was 74.7% and was depending on the polymer concentration. In dissolution studies, initial burst effect around 10-20% from all the formulations was observed and then the release was slowed down and continued at a constant level. In vitro antibiotic release from the microparticles was controlled with the drug carrier system and release fit to Higuchi kinetic model. All the released samples collected at different time intervals during dissolution studies have exhibited intrinsic bactericidal activity against Bacillus subtilis ATCC 6633. WST-1 cell proliferation and viability studies showed that VANCO-loaded levan microparticles at concentrations between 100 μg/mL and 1000 μg/mL were nontoxic to L929 cells. As conclusion, levan microparticulate system could be a potential carrier of antibiotic drugs such as VANCO.
    No preview · Article · Nov 2015 · Pharmaceutical Development and Technology
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    ABSTRACT: We investigated the effect of ciprofloxacin, rifampicine and doxycycline on myeloperoxidase (MPO) activity, glutathione (GSH) and malondialdehyde (MDA) levels in allergic asthma patients and healthy volunteers. Polymorphonuclear leukocytes (PMNs) were isolated with ficoll-hypaque gradient centrifugation method. MPO activity was assayed with modified o-dianisidine, GSH by Ellman's and MDA levels by Beuge's method. PMN functions and MDA levels of patients significantly decreased when compared with healthy volunteers. Ciprofloxacin significantly increased PMN functions, MPO activity and MDA levels of both groups. We have demonstrated that ciprofloxacin has beneficial effects on MPO activity and PMN functions in allergic asthma patients and healthy volunteers.
    No preview · Article · Jun 2015 · Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists
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    Timucin Ugurlu · Erkan Rayaman · Ugur Karacicek
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    ABSTRACT: The purpose of the study was to prepare and evaluate clarithromycin (CLA) floating tablets using experimental mixture design for treatment of Helicobacter pylori provided by prolonged gastric residence time and controlled plasma level. Ten different formulations were generated based on different molecular weight of hypromellose (HPMC K100, K4M, K15M) by using simplex lattice design (a sub-class of mixture design) with Minitab 16 software. Sodium bicarbonate and anhydrous citric acid were used as gas generating agents. Tablets were prepared by wet granulation technique. All of the process variables were fixed. Results of cumulative drug release at 8th h (CDR 8th) were statistically analyzed to get optimized formulation (OF). Optimized formulation, which gave floating lag time lower than 15 s and total floating time more than 10 h, was analyzed and compared with target for CDR 8th (80%). A good agreement was shown between predicted and actual values of CDR 8th with a variation lower than 1%. The activity of clarithromycin contained optimizedformula against H. pylori were quantified using well diffusion agar assay. Diameters of inhibition zones vs. log10 clarithromycin concentrations were plotted in order to obtain a standard curve and clarithromycin activity.
    Full-text · Article · Mar 2014 · Acta poloniae pharmaceutica
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    ABSTRACT: Immunomodulatory products have been used for years in veterinary medicine. Inactivated Parapoxvirus ovis (iPPVO) is currently used in equine medicine as an immunomodulator to improve the immune system and as a prophylactic treatment to prevent or treat infectious diseases. This study was designed to determine the effects of iPPVO on polymorphonuclear leukocyte (PMNL) function (phagocytosis and intracellular killing activity) and the myeloperoxidase (MPO) activity of PMNLs in horses. Twenty-four healthy English thoroughbred horses with an average age of 11 years were included in the study. Venous blood samples (10 ml) were taken before (agent-free controls) and after the administration of iPPVO (2 ml i.m. injection on Days 1, 3, and 5). PMNLs (1 x 107 cells/ml) were isolated from venous blood containing EDTA (0.1 g/ml) with Ficoll-Hypaque gradient centrifugation. Cellular phagocytosis and intracellular killing activities were assayed using a modification of Alexander's method before and after treatment with iPPVO. MPO activity was also measured. The administration of iPPVO significantly increased the phagocytic, intracellular killing, and MPO activities of equine PMNLs (P = 0.0058, P = 0.0050, and P = 0.0070, respectively). This study demonstrates a strong correlation between MPO activity and PMNL function. The administration of iPPVO to horses has a supportive effect on their cellular immunity and an immunomodulatory effect against equine viral infections.
    No preview · Article · Jan 2014 · Veterinární medicína
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    ABSTRACT: Objective: Today it is known that frequently used antineoplastic agents, analgesics and antibiotics affect the immune system cells and can modify polymorphonuclear leukocyte (PMN) functions such as phagocytosis, lymphocyte proliferation and production of various cytokines. In this study we investigated the effect of antidepresssant drugs on PMN functions, serum folic acid, vitamin B12, zinc, copper levels and hematological parameters in the patients with major depression (MD). Material and Method: PMNs were isolated by Ficoll-Hypaque gradient centrifugation method. Phagocytosis and intracellular killing activity were assayed by modifying Alexander's method. Serum folic acid, vitamin B12, copper and hematology parameters were detected with the biochemical analyzer. Serum zinc levels were measured by flame atomic absorption spectrometer. Results: White blood cell (WBC), neutrophil counts (NE) significantly increased after 2 months of antidepressant drug treatment (p<0.05). The phagocytic activity of PMN of MD patients was found same as healthy volunteers, the intracellular killing activity was found lower than that of healthy volunteers. The PMN's phagocytic activity after one and two months of antidepressant drug treatment insignificantly increased and the intracellular killing activity also insignificantly increased after one month of treatment when compared with those before treatment. The results were not found statistically significant. Serum folic acid, vitamin B12, zinc and copper levels were found in reference value intervals compared to those before treatment. Conclusions: This study showed that WBC, NE counts in patients with MD significantly increased in the reference value intervals after antidepressant drug treatment (p<0.05). We conclude that antidepressant drugs have not deleterious effects on PMN functions, serum folic acid, vitamin B12, zinc, copper levels of patients with MD.
    Full-text · Article · Apr 2013 · Nobel medicus
  • U. Soyoǧul Gürer · B. Sümer · E. Rayaman
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    ABSTRACT: The objective of this study was to investigate the effect of antimicrobial cationic peptide nisin (32μg/mL) at minimal inhibitory concentration (MIC) alone in combination with amikacin (21μg/mL), ceftazidime (42μg/mL) and imipenem (50μg/mL) at therapeutic concentrations and their combinations with nisin on polymorphonuclear leukocyte (PMN) functions (phagocytosis and intracellular killing activity) were examined in vitro on 20 healthy volunteers whose mean age was 25. PMNs (1×10 7cells/mL) were isolated by ficoll-hypaque gradient centrifugation method from venous blood with ethylene diaminetetraacetic acid (EDTA). Phagocytosis and intracellular killing activity were assayed by modifying Alexander's method. It was observed that nisin, nisin+amikacin, nisin+ceftazidime and nisin+imipenem combinations significantly decreased phagocytosis and intracellular killing activity of PMNs in healthy volunteers when compared with the control (p<0.001). Consequently, while nisin alone and in combination with amikacin, ceftazidime, and imipenem showed inhibitory activity on PMN functions, amikacin, ceftazidime and imipenem at therapeutic concentraions does not impair normal PMN function.The finding of our study shows the importance of PMN functions for its potential influence in decision of rational antimicrobial selection is extremely important for success of therapy. Additional studies are necessary to elucidate the nature of these immunologic phenomenon.
    No preview · Article · Jan 2012 · Turkish Journal of Pharmaceutical Sciences
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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.
    No preview · Article · Mar 2010 · Medical Principles and Practice
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    Full-text · Article · Jan 2009
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    ABSTRACT: In our study the effects of the antidepressant drugs buspirone (0.0025/μg/ml), sertraline (0.19/μg/ml), citalopram (0.286/μg/ml, 0.502/μg/ml, 0.703/μg/ml) and fluoxetine (0.015/μg/ml, 0.035/μg/ml, 0.055/μg/ml) on polymorphonuclear leukocyte (PMN) function of 20 healthy young volunteers, whose mean age was 25 were investigated in vitro. PMNs (l×l07cell/ml) were isolated by ficoll-hypaque gradient centrifugation method from venous blood with EDTA. Phagocytosis and intracellular killing activity were assayed by modifying Alexander's method. Fluoxetine at 0.035/μg/ml concentration has significantly increased the PMN's phagocytic activity, of the healthy young volunteers but did not effect their PMN's intracellular killing activity. The results might bring a new immunotherapeutic approach to the therapy of the major depressant patients whose immune system is suppressed.
    No preview · Article · Jan 2009 · Turkish Journal of Pharmaceutical Sciences
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    ABSTRACT: Zinc supplementation can stimulate polymorphonuclear leukocyte (PMN) functions (phagocytosis and intracellular killing activity) in older hypertensive patients and healthy young volunteers. The aim of this study is to investigate the effect of zinc supplementation on polymorphonuclear leukocyte (PMN) functions (phagocytosis and intracellular killing activity) in vitro in 13 older hypertensive patients and compare these functions with those of 10 healthy young volunteers. PMNs were isolated by ficoll-hypaque gradient centrifugation method from venous blood with EDTA (0.1g/ml).Phagocytosis and intracellular killing activity were assayed by modifying Alexander's method. The subjects were given zinc supplementation 22mg/daily/30 days. Serum zinc levels were measured by flame atomic absorption spectrometer. The serum zinc levels and the PMN's intracellular killing activities of older hypertensive patients before zinc supplementation were significantly low when compared with that of healthy young volunteers (p<0.001, p=0.001 respectively). After zinc supplementation the PMN's phagocytic and intracellular killing activities of older hypertensive patients were significantly lower than those of healthy young volunteers (p<0.001, p<0.05 respectively). However the serum zinc level of the elderly increased after zinc supplementation when compared with that before supplementation . The serum zinc levels and PMN's phagocytic activity of healthy young volunteers significantly increased after zinc supplementation (p<0.05). Consequently, the serum zinc levels of the older hypertensive patients and young volunteers increased after zinc supplementation. Adequate zinc supplementation may improve PMN functions both in older hypertensive patients and healthy young volunteers.
    No preview · Article · Jan 2009 · Turkish Journal of Pharmaceutical Sciences
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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 .
    Full-text · Article · Jan 2008 · Turkish Journal of Pharmaceutical Sciences
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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.
    Preview · Article · Jan 2007 · Turkish Journal of Pharmaceutical Sciences
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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.
    No preview · Article · May 2006 · International Immunopharmacology
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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.
    No preview · Article · Nov 2005 · Medical Principles and Practice
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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.
    No preview · Article · May 2005 · International Immunopharmacology