Murat Boyacioglu

Comparison of In Vitro Antimicrobial Susceptibility in Flavobacterium psychrophilum Isolated from Rainbow Trout Fry

The aim of this study was to demonstrate the presence of Flavobacterium psychrophilum in the west Aegean region of Turkey and to evaluate the in vitro susceptibility of F. psychrophilum (isolated from the fry of rainbow trout Oncorhynchus mykiss) to seven antimicrobial agents, as determined by the disk diffusion and agar dilution methods. A total of 250 rainbow trout fry (weight = 2-5 g; total length = 3-6 cm) were examined, and 20 bacterial isolates were phenotypically identified. Antimicrobial agents included in this investigation were amoxicillin-clavulanic acid (AMC), erythromycin (E), enrofloxacin (ENR), florfenicol (FFC), gentamicin (CN), oxytetracycline (OT), and sulfamethoxazole-trimethoprim (SXT). Disk diffusion and agar dilution methods were performed according to published standards. Minimum inhibitory concentration (MIC) ranges were determined using the agar dilution method for F. psychrophilum isolates. Resistance of F. psychrophilum to CN (disk diffusion method: 70%; agar dilution method: 95%), E (65%; 100%), and SXT (75%; 100%) was high using both methods. Resistance to ENR (10%; 15%) and FFC (25%; 25%) was low with both methods; MIC90 (minimum concentration required to inhibit bacterial growth by 90%) was 4 microg/mL for ENR and 16 microg/mL for FFC. Ninety percent of the F. psychrophilum isolates were resistant to AMC based on the disk diffusion method, while only 15% of isolates showed resistance based on the agar dilution method. For OT, 20% of isolates were resistant based on disk diffusion, while 75% exhibited resistance based on agar dilution. The importance of susceptibility testing when facing an outbreak of F. psychrophilum at a fish farm is obvious; however, the discrepancies between testing methods for AMC and OT require further studies.

The Effect of L-Carnitine on Oxidative Stress Responses of Experimental Contrast-Induced Nephropathy in Rats

ABSTRACT This study was conducted to investigate the prophylactic effects of carnitine against contrast-induced nephropathy (CIN) and its relation to oxidant/antioxidant status in kidney, liver, heart, spleen and lung tissues in a CIN rat model. Twenty-eight adult male Wistar rats were divided into 4 groups, the control, contrast media (CM), carnitine and contrast media+carnitine (CM+carnitine) groups. Animals were placed in individual metabolism cages, and on the 2nd day, rats were deprived of water for 24 hr. On the 3rd day, contrast media were administered to groups CM and CM+carnitine. L-carnitine was administered on days 2, 3 and 4. Histopathological changes were evaluated in the right kidney after euthanization. Superoxide dismutase (SOD) and catalase (CAT) activities and glutathione (GSH) and malondialdehyde (MDA) levels were measured in renal, liver, heart, spleen and lung tissues. The SOD activities in the renal (P<0.05), liver (P<0.001) and spleen (P<0.05) tissues were increased in the carnitine group. The CAT activities in the spleen tissue were decreased (P<0.01) only in the CM group. Renal (P<0.05), liver (P<0.001), spleen (P<0.001) and lung tissue (P<0.01) GSH levels were found to be higher in the carnitine group. In renal, liver and lung tissues, the MDA levels increased in the CM group (P<0.001). The histopathological findings showed that L-carnitine may have a preventative effect in alleviating the negative effects of CIN. Similar to this, L-carnitine may play a major role in the stability of the antioxidant status in the kidney, liver, spleen and lung of the CIN rat model.

Pharmacokinetics of danofloxacin following intravenous and intramuscular administration in donkeys

Danofloxacin (DNF) is a synthetic antibacterial agent of thefluoroquinolone group, developed specifically for use in veteri-nary medicine. The drug possesses good in vitro activity against avariety of pathogens, including gram-positive and gram-negativebacteria, mycoplasmas, and intracellular pathogens, such asBrucella and Chlamdia species; but it has poor activity againstanaerobes (Wolfson & Hooper, 1985; Neu, 1987; McKellar et al.,1998; Aliabadi et al., 2003a).Danofloxacin shares with other fluoroquinolones, such asenrofloxacin and ciprofloxacin, a wide spectrum of activity, alarge volume of distribution and activity at low concentrations(Van Cutsem et al., 1990; Spreng et al., 1995; Brown et al.,1996). Pharmacokinetic properties of different fluoroquinol-ones have been extensively studied on several animal species(Knoll et al., 1999; Atef et al., 2001; Fernandez-Varon et al.,2006). In addition, some fluoroquinolones, such as DNF,moxifloxacin, marbofloxacin and enrofloxacin, are being usedwidely in horses (Bertone et al., 2000; Carretero et al., 2002;Gardner et al., 2004). Pharmacokinetic disposition of DNF hasbeen evaluated in many animal species including cattle, goats,sheep, camels, rabbit, chickens, turkeys, pig and horses (Knollet al., 1999; McKellar et al., 1999; Lindecrona et al., 2000;Atef et al., 2001; Aliabadi et al., 2003a,b; Shojaee Aliabadi L Haritova et al., 2006; Fernandez-Varon et al.,2006, 2007).There is a paucity of data available on the pharmacokineticsof drugs used in donkeys including antibiotics, as donkeys areoften neglected species in domestic animals. Different classes ofdrugs used in horses and ruminants are commonly extrapo-lated to donkeys without optimization of dosing regimens anddetermination of pharmacokinetic and pharmacodynamicproperties. Because of the lack of registered drugs for donkeys,antimicrobials licensed for horses or ruminants are used fortreatment of bacterial infections in this species with same doserates. In the literature, data are available only on thepharmacokinetics of gentamicin, sulfamethoxazole with tri-methoprim and marbofloxacin in donkeys (Welfare et al.,1996; Peck et al., 2002; Gonza´lez et al., 2007). It has beenreported that donkeys have a greater capacity to metabolizecertain drugs compared with horses; thus higher dosage orshorter intervals are required for maintaining effective con-centrations (Welfare et al., 1996; Matthews et al., 1997Coakley et al., 1999; Peck et al., 2002). Therefore, the aimof the present study was to determine the pharmacokineticproperties of DNF in donkeys following intravenous (i.v.) andintramuscular (i.m.) administration at single dose of1.25 mg⁄kg bodyweight.Six native breed donkeys (Equus asinus) which ranged in agefrom 2 to 5 years and weighted 90–125 kg were used in thisstudy. The animals were kept indoors and had clover hay andwater available ad libitum throughout the course of the study.This study was approved by Animal Ethic Committee ofUniversity of Adnan Menderes. The animals were allocated intotwo groups of three such that the mean weight of animals ineach group was similar and the donkeys were identified byunique freeze brand or natural markings. Danofloxacin wasadministered according to a two-phase crossover design proto-col. In phase I, group I received i.v. the commercially availableinjectable solution of DNF (Advocin , 2.5% w⁄v, Pfizer, Turkey)at a dose of 1.25 mg⁄kg bodyweight and group II received i.m.the same formulation at the same dose rate into gluteal muscle.A 2-week washout period was allowed between the two phases.Heparinized blood samples (5 mL) were collected 1 h prior todrug administration and 5, 15, 30, 45 min and 1, 1.5, 2, 3, 4, 6,8, 12, 24, 32, 36 and 48 h post-treatment. Blood samples werecentrifuged at 5000 g for 20 min and plasma was transferred toplastic tubes. All the plasma samples were stored at )20 C untilthe determination of drug concentration. In addition, serumsamples were also collected to determine creatin kinase (CK)activity after i.m. administration. The samples were stored at4 C for 2 h until CK activity (expressed in U⁄L), which wasmeasured preinjection and after i.m. injection using a commer-cial available kit (CK EE547; Linear Chemicals , Barcelona,Spain).

Protective effect of cholesterol-loaded cyclodextrin pretreatment against hydrogen peroxide induced oxidative damage in ram sperm

Three experiments were conducted to determine the protective effect of cholesterol-loaded cyclodextrin (CLC) against hydrogen peroxide (H2O2) or cryo-induced damage in ram sperm. In Experiment 1, the fresh ejaculates were either treated with CLC or remained untreated. Both CLC treated and untreated samples were then incubated with 0, 250 or 500 μM H2O2 at 35°C for 12 h. After incubation period of 12 h, the motility, viability and membrane integrity remained higher in CLC treated sperm even in the presence of 250 or 500 μM H2O2. The H2O2 treatment affected all the sperm parameters adversely (P<0.05). However, compared to CLC untreated counterpart, the motility, viability and membrane integrity remained higher (P<0.05) in treated sperm, even in the presence of 250 or 500 μM H2O2 during 12 h of incubation. In Experiment 2, semen was cryopreserved in the presence or absence of CLC. The post-thaw results revealed that CLC treated sperm has higher (P<0.05) motility, viability and membrane integrity compared to the control. In Experiment 3, lipid peroxidation levels were assessed by determining malondialdehyde (MDA) concentrations during the H2O2-induced oxidative stress in CLC treated and untreated sperm. However, no difference (P>0.05) in MDA level was observed among the groups at any stage of incubation. In conclusion, the CLC incorporation in ram sperm membrane may protects it against H2O2 or cryo-induced oxidative damage. The cryoprotective influence of CLC on ram sperm might be resulted from, at least partly, its antioxidative property.

The protective effects of vitamin C on the DNA damage, antioxidant defenses and aorta histopathology in chronic hyperhomocysteinemia induced rats

The aim of this study was to investigate the protective effect of vitamin C towards hyperhomocysteinemia (hHcy) induced oxidative DNA damage using the comet assay. The increase in plasma homocysteine levels is an important risk factor for vascular and cardiovascular diseases through free radical production. This study was also conducted to investigate the histopathological changes in the thoracic aorta and the oxidant/antioxidant status in heart, liver and kidney tissues. Twenty-four adult male Wistar rats were divided as control, hHcy and hHcy+vitamin C group. Chronic hHcy was induced by oral administration of l-methionine (1g/kg/day) for 28 days. Vitamin C was given 150mg/kg/day within the specified days. DNA damage was measured by use of the comet assay in lymphocytes. Levels of malondialdehyde (MDA) and glutathione (GSH) as well as catalase (CAT) and superoxide dismutase (SOD) activities were determined in heart, liver and renal tissues. Results show that l-methionine administration significantly increased % Tail DNA and Mean Tail Moment in hHcy group as compared with other groups. Vitamin C treatment significantly decreased the high MDA levels and increased activity of antioxidant enzymes in tissues. Aortic diameter and thickness of aortic elastic laminae were significantly lower in hHcy+vitamin C group. Comet assay can be used for the assessment of primary DNA damage caused by hHcy. Histopathological findings showed that vitamin C may have a preventive effect in alleviating the negative effects of hHcy. Vitamin C might be useful in the prevention of endothelial dysfunction caused by hHcy.

The effect of sesame and sunflower oils on the plasma disposition of ivermectin in goats

The effect of sesame oil (SSO) and sunflower oil (SFO) (the excipients) on the plasma disposition of ivermectin (IVM) following intravenous (i.v.) and subcutaneous (s.c.) administration at a dosage of 200 microg/kg was investigated in goats. Ten clinically healthy crossbred goats were used in the study. The animals were allocated by weight and sex into two groups of five animals each. Group 1 (n = 5) received the drug and excipient by the i.v. route only and group 2 received drug and excipient by the s.c. route only. The study was designed according to a two-phase crossover design protocol. In the first phase three animals in group 1 were i.v. administered IVM (0.2 mg/kg) + SSO (1 mL) and the other two animals received IVM (0.2 mg/kg) + SFO (1 mL). In the second phase animals were crossed over and received the alternate excipient with IVM at the same dosages. In group 2 during the first phase, three animals were s.c. administered IVM (0.2 mg/kg) + SSO (1 mL) and the other two animals were received IVM (0.2 mg/kg) + SFO (1 mL). In the second phase animals were crossed over and received the alternate excipient with IVM at the same dosages. A 4-week washout period was allowed between the two phases. In group 2 significantly increased dermal thickness was observed at the s.c. injection site of the all animals which received IVM during phase I regardless of the excipient. There was almost no change observed at the injection site of any animal during the second phase of the study following s.c. administration. In group 2 the plasma concentrations of IVM in the second phase for both excipient combinations were much higher than the plasma concentrations following first administration and appeared to be related with the dermal changes. The mean plasma disposition of IVM in combination with SSO or SFO was similar following i.v. administration. Longer terminal elimination half-lives and resultant longer mean resident time were observed after s.c. administration of the both combinations compared with i.v. administration.

Nebivolol to attenuate the effects of hyper-homocysteinaemia in rats

OBJECTIVE This study investigated the prophylactic effect of nebivolol against hyper-homocysteinaemia (hHcy) induced oxidative stress in brain, heart, liver and kidney tissues and histomorphometric changes in the thoracic aorta. METHODS Twenty-four adult male Wistar rats were divided into a control, nebivolol, hHcy and nebivolol+hHcy group. hHcy was induced by oral administration of L-methionine (1 g/kg/day) for 28 days. 10 mg/kg/day nebivolol was administered orally for 28 days. Malondialdehyde (MDA) and glutathione (GSH) levels and catalase (CAT) and superoxide dismutase (SOD) activities in the tissues were determined. The total cross-sectional area (TCSA), luminal cross-sectional area (LCSA) and intima-media thickness (IMT) were measured in the thoracic aorta. RESULTS Homocysteine (Hcy) levels were lower in the nebivolol+hHcy group than in the hHcy group. Nebivolol treatment significantly decreased high MDA levels in the brain, heart and liver tissues. The level of GSH was higher in the brain, heart and kidney tissues of the nebivolol+hHcy group (P<0.001). The activity of CAT increased only in the kidney tissue of the nebivolol+hHcy group (P<0.01), and the activity of SOD was significantly increased in all the tissues in this group. Increased TCSA and IMT in the nebivolol+hHcy group were significantly decreased after nebivolol administration. The LCSA was significantly higher in the hHcy group than the control group, probably due to outward vascular remodelling. CONCLUSION Nebivolol treatment may be useful in different clinical scenarios where hHcy affects physiopathological pathways.

The first histopathological evidence of trimetazidine for the prevention of contrast-induced nephropathy.

Abstract Aim: We aimed to investigate the prophylactic effects of trimetazidine (TMZ) against contrast-induced nephropathy (CIN) in rat kidneys. Methods and results: 28 Wistar rats were divided into 4 groups of 7 rats each (control (C), contrast media (CM) TMZ, trimetazidin + contrast media groups (TMZ + CM). The administration of TMZ solution was done on d2, d3 and d4. Fifth day, contrast media was administered at a single dose. On d6 scarification was performed. The oxidant/antioxidant parameters were measured and histopathological scores were performed in kidney tissues. Most of the histopathological scores were significantly higher in the CM group as compared to other groups. Moreover, the scores of the TMZ + CM and C groups were not statistically different. CM group, had significantly higher levels of MDA compared to the C and CM + TMZ groups (562.82 ± 38.15 vs. 419.15 ± 49.01 and 507.34 ± 14.16 01 nmol/mg protein respectively) (p < 0.001). CM group had significantly lower levels of SOD as compared to C, CM + TMZ and TMZ groups (p < 0.05). Conclusion: To the best of our knowledge, this study for the first time, histopathologically demonstrated the effectiveness of TMZ for the prevention of CIN.

The usefulness of carvedilol and nebivolol in preventing contrast nephropathy in rats

Abstract Background: Oxidative stress and vasoconstriction appear to be important components of contrast nephropathy (CN) pathogenesis, and both carvedilol and nebivolol are known to have vasodilatory and antioxidant effects. Aims: This study aimed to investigate whether carvedilol and nebivolol play preventive roles against developing CN and to compare the effects of each. Materials and methods: Wistar albino rats were divided into control (C, n = 6), contrast material (CM, n = 6), carvedilol (CV, n = 7), carvedilol + contrast material (CV + CM, n = 7), nebivolol (N, n = 7), and nebivolol + contrast (N + CM, n = 7) groups. Following 3 days of dehydration, 6 mL/kg diatrizoate was administered to each rat. Carvedilol was given at a dose of 2 mg/kg and nebivolol at a dose of 1 mg/kg by way of oral gavage. After scarification, total antioxidant capacity (TAC), malondialdehyde (MDA), and superoxide dismutase (SOD) were studied in renal tissue. Histopathological findings were graded as mild (+), moderate (++), and severe (+++). Results and discussion: Most of the histopathological findings and MDA levels were significantly higher in the CM group than that in the C, CVCM, and NVCM groups, whereas there was no significant difference between the C, CVCM and NVCM groups. TAC level in the CM group was significantly lower than in all other groups. There was no difference in SOD among groups. Conclusions: Carvedilol and nebivolol both prevent development of nephropathy related to CMs by decreasing oxidative stress. Neither is superior to the other.

S100A1 as a Potential Diagnostic Biomarker for Assessing Cardiotoxicity and Implications for the Chemotherapy of Certain Cancers

This study examined the value of blood marker S100A1 in detecting cardiotoxicity induced by chemotherapy agents; trastuzumab and lapatinib, in normal rat heart. The rats were divided into three groups: control (n = 8, no treatment), T (n = 8, one time ip treatment with 10 mg/kg trastuzumab) and L (n = 8, oral treatment with 100 mg/kg/day lapatinib for 7 days). The activities of oxidative stress parameters Malondialdehyde (MDA), Superoxide dismutase (SOD), Catalase (CAT) and Glutathione (GSH) were measured from the extracted cardiac tissues. The levels of troponinI and S100A1 expressions were measured from blood samples. All biomarkers responded to the treatments as they exhibited alterations from their normative values, validating the chemically induced cardiotoxicity. S100A1 expression attenuated significantly (75%), which made the sensitive detection of cardiotoxicity feasible. Assessment of cardiotoxicity with S100A1 may be a valuable alternative in clinical oncology of cancers in some organs such as breast and prostate, as they do not overexpress it to compete against.