Burak Dik

Pharmacokinetics of meloxicam in red-eared slider turtles (Trachemys scripta elegans) after single intravenous and intramuscular injections

OBJECTIVE To determine the pharmacokinetics of meloxicam after single IV and IM injections in red-eared slider turtles (Trachemys scripta elegans). ANIMALS 8 healthy red-eared slider turtles. PROCEDURES Turtles received 1 dose of meloxicam (0.2 mg/kg) IV or IM (4 turtles/route), a 30-day washout period was provided, and then turtles received the same dose by the opposite route. Blood samples were collected at predetermined times for measurement of plasma meloxicam concentration. Pharmacokinetic values for each administration route were determined with a 2-compartment open model approach. RESULTS For IV administration, mean ± SD values of major pharmacokinetic variables were 1.02 ± 0.41 hours for distribution half-life, 9.78 ± 2.23 hours for elimination half-life, 215 ± 32 mL/kg for volume of distribution at steady state, 11.27 ± 1.44 μg•h/mL for area under the plasma concentration versus time curve, and 18.00 ± 2.32 mL/h/kg for total body clearance. For IM administration, mean values were 0.35 ± 0.06 hours for absorption half-life, 0.72 ± 0.06 μg/mL for peak plasma concentration, 1.5 ± 0.0 hours for time to peak concentration, 3.73 ± 2.41 hours for distribution half-life, 13.53 ± 1.95 hours for elimination half-life, 11.33 ± 0.92 μg•h/mL for area under the plasma concentration versus time curve, and 101 ± 6% for bioavailability. No adverse reactions were detected. CONCLUSIONS AND CLINICAL RELEVANCE Long half-life, high bioavailability, and lack of immediate adverse reactions of meloxicam administered IM at 0.2 mg/kg suggested the possibility of safe and effective clinical use in turtles. Additional studies are needed to establish appropriate administration frequency and clinical efficacy.

Assessment of the cardiotoxicity of tulathromycin in rabbits.

The aim of this study was to determine the cardiotoxic potency of tulathromycin. Tulathromycin (10 mg/kg, SC) was administered to ten adult male rabbits, and blood samples were obtained before and after drug administration (0 and 6 hours). Serum cardiac damage markers (troponin I, creatine kinase-MB, myoglobin, lactate dehydrogenase, aspartate aminotransferase), routine serum biochemical values (alkaline phosphatase, alanine aminotransferase, gamma-glutamyltransferase, creatinine, blood urea nitrogen, cholesterol, triglyceride, high-density lipoprotein, amylase, total protein, albumin, glucose, calcium, ionised calcium, sodium, potassium), white blood cell (WBC) and red blood cell (RBC) counts, arterial blood gas parameters (pH, partial carbon dioxide pressure, partial oxygen pressure, actual bicarbonate, standard bicarbonate, total carbon dioxide, base excess in vivo, base excess in vitro, oxygen saturation, packed cell volume, haemoglobin) and serum oxidative status (malondialdehyde, nitric oxide, superoxide dismutase, retinol, β-carotene) were measured. Increased levels of troponin I, creatine kinase-MB and creatinine, and decreased WBC counts, ionised calcium and potassium levels were observed after drug administration. Tulathromycin treatment may cause cardiotoxicity, but its effects may be less dramatic than those of other macrolide antibiotics frequently used in veterinary medicine.

Combined Treatment with Interlukin-1 and Tumor Necrosis Factor-Alpha Antagonists Improve Type 2 Diabetes in Rats

In the present study, combined treatment with etanercept and anakinra were tested in the streptozotocin-induced diabetic rats. Forty male Wistar albino rats were divided into 5 groups: healthy control (HC), diabetic control (DC), diabetic + anakinra (DAT), diabetic + etanercept (DET), and diabetic + etanercept + anakinra (DEAT). HC and DC groups received subcutaneous (s.c.) injection with a saline solution, while DAT and DET groups received anakinra (10 mg/kg per day, s.c.) or etanercept (10 mg/kg, twice a week, s.c.), and DEAT rats received both anakinra and etanercept treatments for 21 days after diabetes has developed. Anakinra and etanercept treatments significantly increased insulin and homeostatic model assessment β-cell function levels and decreased glucose levels compared to the DC group as single (DAT and DET) and combined treatments (DEAT). The thiobarbituric acid reactive substances level was significantly decreased in DAT group. The combine use of etanercept and anakinra can improve insulin and blood glucose in type 2 diabetic rats. The combined treatment of anakinra and etanercept together was more effective than single treatment and might have a potential new treatment strategy and to reduce the mortality and morbidity resulting from diabetes.

Cardiac Safety of Diclofenac at a Single Dose in Ram

Nonsteroidal anti-inflammatory drugs are frequently prescribed drug group in human and veterinary medicine. However, diclofenac, a traditional nonsteroidal anti-inflammatory drug, related to cardiotoxicity is reported, and blood cardiac damage markers may increase within the first hours after damage. The aim of the current research was to determine the effect of diclofenac on the blood cardiac damage markers. Single dose of diclofenac (2.5 mg/kg, IM) was injected to 6 rams. Blood samples were collected in before (0 hour, control) and 6 hours after injection. Specific (troponin I, and creatine kinase-MB) and nonspecific (lactate dehydrogenase, aspartate aminotransferase) blood cardiac damage marker concentrations, routine biochemical (hepatic damage, renal damage, lipid metabolism, glucose, and phosphorus) parameters, and hemogram values were measured. Diclofenac increased (P < 0.05) specific (troponin I) and nonspecific cardiac (lactate dehydrogenase, aspartate aminotransferase), hepatic (aspartate aminotransferase, alkaline phosphatase, and alanine aminotransferase), and muscular (creatine kinase) damage markers and high density lipoprotein level, while it decreased (P < 0.05) low density lipoprotein level. Moreover, diclofenac decreased (P < 0.05) white blood cell counts and increased (P < 0.05) red blood cell counts. In conclusion, it may be stated that diclofenac shows slight cardiotoxicity, whereas it may show potent hepatic and muscular damage effects at an intramuscularly single dose in sheep. Thereby, repeated injections of diclofenac may be more harmful in sheep.

Sulfasalazine treatment can cause a positive effect on LPS-induced endotoxic rats

The aim of this study, was to determine the effect of sulfasalazine for different periods of time reduces disseminated intravascular coagulation, inflammation and organ damages by inhibiting the nuclear factor kappa beta pathway. The study was performed with 30 Wistar albino rats and the groups were established as Control group, LPS group; endotoxemia was induced with LPS, SL5 group: sulfasalazine (300 mg/kg, single dose daily) was administered for 5 days before the LPS-induced endotoxemia, and LS group: sulfasalazine (300 mg/kg, single dose) was administered similtenously with LPS. Hemogram, biochemical, cytokine (IL-1β, IL-6, IL-10, TNF-α) and acute phase proteins (HPT, SAA, PGE2) analyzes and oxidative status values were measured from blood samples at 3 and 6 h after the last applications in the all groups. The rats were euthanized at 6 h and mRNA levels of BCL2 and BAX genes were examined from liver and brain tissues. Sulfasalazine reduced the increased IL-1β, IL-6, TNF-α and PGE2 levels and significantly increased anti-inflammatory cytokine IL-10 levels. In addition, decreasing of ATIII level was prevented in the SL5 group, and decreasing of fibrinogen levels were prevented in the LS and SL5 groups within first 3 h. In LPS group, leukocyte and thrombocyte levels were decreased, however sulfasalazine application inhibited decreases of leukocyte levels in LS and SL5 groups. In addition, sulfasalazine inhibited the decrease of total antioxidant capacity and unchanged apoptosis in brain and liver. In conclusion, the use of sulfasalazine in different durations reduce the excessive inflammation of endotoxemia cases.

Investigation of the Effect of Tarantula cubensis Extract on Acute Phase Response

Background: Tarantula cubensis alcoholic extract is used to accelerate wound healing and to relieve edema in many animal species. In addition, it may be useful for many infectious diseases. Considering to these effects, it is believe that these effects may be on immune system. Cytokines (tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, interleukin-10 and interferon gamma) secreted by immune cells and acute phase proteins (haptoglobin, alpha 1 acid glycoprotein, serum amyloid A) secreted by liver play role in acute phase response. The aim of the present study was to determine the effect of Tarantula cubensis alcoholic extract on cytokine and acute phase protein levels in sheep. Materials, Methods & Results: Tarantula cubensis alcoholic extract (6 mL/sheep, subcutaneously, single dose) was administered to 6 healthy sheep. Blood samples were obtained before (0 h) and after treatments at 2, 4, 8, 12, 24 and 48 h. Then, blood samples were centrifuged to obtain serum samples. Acute phase cytokines such as serum tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, interleukin-10, interferon gamma and acute phase proteins such as haptoglobin, alpha 1 acid glycoprotein and serum amyloid-A concentrations were determined with commercially available kits on ELISA reader. Administration of Tarantula cubensis alcoholic extract caused fluctuations in tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, interleukin-10, interferon gamma levels in sheep. In addition, levels of haptoglobin, alpha 1 acid glycoprotein, serum amyloid A showed fluctuations. But, these fluctuations in acute phase cytokines and acute phase proteins were not statistically significant (P > 0.05). Discussion: Tarantula cubensis alcoholic extract, homeopathic medicine, is used trauma, retentio secundinarium, tendinitis, bluetongue, foot and mouth, metritis and arthritis in many animal species including sheep. Cytokines, secreted against various stimulus including infectious diseases, play role in wound healing and in the regulation of the immune system. In current study, administration of Tarantula cubensis alcoholic extract lead to fluctuations in tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, interleukin-10 and interferon gamma levels, but these changes were not statistically significant (P > 0.05). Non-statistical fluctuations in cytokines result from inadequate immunological response of sheep against to Tarantula cubensis alcoholic extract. Also, use of molecular analysis techniques may be changed these results. Acute phase proteins are significantly secreted from the liver during the acute phase response. In current study, administration of Tarantula cubensis alcoholic extract in sheep caused non-statistifical fluctuations on haptoglobin, alpha 1 acid glycoprotein and serum amyloid A levels (P > 0.05). Tumor necrosis factor alpha and interleukin-1 beta stimulate synthesis of interleukin-6. Interleukin-6 provides synthesis of acute phase proteins in liver. Non-statistical fluctuations in acute phase proteins result from inadequate stimulus of IL-6. In conclusion, it may be stated that administration of Tarantula cubensis alcoholic extract has no distinctive effect on the acute phase response. However, when Tarantula cubensis alcoholic extract is administered repeated times or other acute phase parameters are evaluated, different results may be observed.

A Cardioprotective Role of Nerium oleander with the Expression of Hypoxia Inducible Factor 2A mRNA by Increasing Antioxidant Enzymes in Rat Heart Tissue

Background: Nerium oleander (NO) distillate is used to either protect heart cells against oxidative stress or reduce the risk of cardiovascular disease by regulating the production of reactive oxygen species. Hypoxia-inducible factors (HIFs) regulate cellular antioxidant defense mechanisms under hypoxic conditions in which heart cells survive; however, the key responsible mechanism of NO distillate for cardioprotection remains elusive. The objective of this study was to evaluate the effects on heart tissue at different time intervals after administering NO distillate intraperitoneally (IP) while considering the transcriptional regulation of HIFs and representative antioxidant enzymes. Materials, Methods a Results: The NO plant was chopped, and distillated water was added. The mixture was distilled, and the distillate separated and collected into tubes, after which it was lyophilized to obtain dry material. Twenty male Wistar albino rats (2-3 month-old, 250-300 g each) were used in the study. The rats were randomly divided into four groups. The control group (n = 5) received IP injections of saline; the remaining 15 rats received IP injections of a single dose of 7.5 mL NO distillate. The NO distillate injected rats were divided into three groups according to the time from injection to harvest the heart tissue samples. The tissues were collected at 0 h (control; n = 5), 2 h (group 2; n = 5), 4 h (group 3; n = 5), and 8 h (group 4; n = 5) after injection and under general anesthesia (60 mg/kg ketamine, IP + 10 mg/kg xylazine, IP). Quantitative polymerase chain reaction (qPCR) was used to assess the expression profiles of the genes of interest in the heart tissues. Hypoxanthine phosphoribosyltransferase was used as the reference gene. The expression of manganese superoxide dismutase (MnSOD) mRNA was in a steady state level between the control group and group 2 (P g 0.05); however, it significantly increased in group 3 and 4 compared with that in the control (P l 0.05). Expression of catalase (CAT) mRNA was significantly higher in group 2 than in the control group (P l 0.05) although it was lower in group 3 and 4 than in group 2 (P l 0.05); however, it appeared to be similar among the control group, group 3, and group 4 (P g 0.05). Copper (Cu) SOD mRNA was equally expressed in both the control group and group 2 (P g 0.05) but was lower in group 3 and 4 than in group 2 (P l 0.05). Expressions of HIF1A, HIF2A, and HIF3A mRNA were detected in the rat heart tissues in the control and 2, 4, and 8 h after administration of NO distillate. Expression of HIF1A mRNA was in a steady state and did not differ among groups 2, 3, and 4 (P g 0.05). Similarly, the expression of HIF2A mRNA did not change between the control group and group 2 (P g 0.05); however, it was higher in group 3 than in the control (P l 0.05) and tended to be higher in group 3 than in group 2 (P = 0.063). HIF3A mRNA expression did not change significantly in the heart tissue of any of the groups (P g 0.05). Discussion: The present study using rats determined that MnSOD, CAT, CuSOD, HIF1A, HIF2A, and HIF3A mRNA are expressed in the heart tissues after administration of NO distillate. The increased expression of HIF2A mRNA after 4 h in accordance with a rise in CAT mRNA after 2 h, and MnSOD mRNA after 4 and 8 h might confirm the role of HIF2A mRNA in oxidative stress defense by regulating antioxidant enzymes; consequently, this study may expand our understanding of uses of NO distillate with respect to molecular pathways.

Effect of Anti-TNF-α on the Development of Offspring and Pregnancy Loss During Pregnancy in Rats

Background: Etanercept binds soluble tumor necrosis factor-alpha (TNF-α) and is classified as pregnancy risk category B. Increase in TNF-α level causes preterm labour or miscarriage. Lipopolysaccharides trigger preterm birth and abortion via producing of pro-inflammatory cytokines. Cytokines are divided into two groups as pro-inflammatory and anti-inflammatory. TNF-α is a pro-inflammatory cytokine, whereas interleukin (IL)-10 is an anti-inflammatory cytokine. IL-10 predominant in normal pregnancy while TNF-α characterize in abortion and recurrent abortion. The aim of this study was to determine the effect of etanercept on the development of offspring and lipopolysaccharide-induced pregnancy loss. Materials, Methods & Results: Twenty-eight female and 7 male Wistar rats (5-6 months old) were used in this study. The rats were fed a standard pelleted diet and tap water ad libitum. After female rats were caged with males for 1 day, the presence of a vaginal plug was designated as day 0 of pregnancy. Twenty-eight pregnant Wistar rats were divided into 4 equal groups, as follows: control (0.3 mL of Normal Saline Solution intravenously on day 10 of pregnancy); etanercept (0.8 mg kg-1/day intraperitoneally on days 9 and 10 of pregnancy); lipopolysaccharide (160 µg kg-1 intravenously on day 10 of pregnancy); and etanercept + lipopolysaccharide. Blood samples were obtained from the tail vein on day 10 of pregnancy (3 h after lipopolysaccharide administration). All animals were followed during pregnancy. Pregnancy rates and offspring characteristics were determined. TNF-α and IL-10 levels were measured using an ELISA reader. Etanercept alone did not have any negative effects, and etanercept did not prevent (P < 0.05) lipopolysaccharide-induced pregnancy loss. Higher TNF-α and IL-10 levels were measured (P < 0.05) in the etanercept + lipopolysaccharide group compared to other groups. Discussion: It is well known that use of etanercept does not increase pregnacy loss. In this study, higher pregnancy rates were determined in the control and etanercept groups than the lipopolysaccharide and etanercept + lipopolysaccharide groups. The proportion of fetal deaths in lipopolysaccharide administered pregnant subjects was decreased by the use of anti-TNF-α agents. While the concentrations of TNF-α are low in the onset of pregnancy period, the concentrations of TNF-α increases a peak level during the onset of labour. Embryonic resorption is affected by Th1 cytokines (TNF-α and lL-2) and low-dose lipopolysaccharide without any affecting mother survival, and in the early pregnancy term, the implantation area of embryo is enormously sensitive to these molecules. In the current study, etanercept increased the concentration of TNF-α and the concentration of IL-10 when compared to the lipopolysaccharide group. IL-10 has a protective role, while TNF-α is an abortive factor during pregnancy. Thus, etanercept did not prevent pregnancy loss. This finding may have reflected an insufficient dose of etanercept. Adverse effects did not occur in the offspring of the etanercept or control groups, and there was no difference between the two groups statistically. Adverse pregnancy outcomes such as stillbirth, low birth weight, spontaneous abortion and herediter malformations are not associated with TNF-α inhibitors. In conclusion, etanercept does not pose a major teratogenic risk and has no preventive effects with respect to infection-dependent pregnancy loss.

Pharmacokinetics of ceftiofur in healthy and lipopolysaccharide-induced endotoxemic newborn calves treated with single and combined therapy

The aim of this research was to compare plasma pharmacokinetics of ceftiofur sodium (CS) in healthy calves, and in calves with experimentally induced endotoxemia. Six calves received CS (2.2 mg/kg, IM) 2 hr after intravenous administration of 0.9% NaCl (Ceft group). After a washout period, the same 6 calves received CS 2 hr after intravenous injection of lipopolysaccharide (LPS+Ceft group). Another group of 6 calves received a combination of drug therapies that included CS 2 hr after administration of 0.9% NaCl (Comb group). A third group of 6 calves received the same combination therapy regimen 2 hr after intravenous injection of lipopolysaccharide (LPS+Comb group). Plasma concentrations of CS and all desfuroylceftiofur-related metabolites were determined using HPLC, and its pharmacokinetic properties were determined based on a two-compartment model. The peak concentration of CS in the LPS+Comb group occurred the earliest, and the clearance rate of CS was the highest in the Comb and LPS+Comb groups (P<0.05). The elimination half-life of CS in the LPS+Ceft group was longer than that in the Ceft and Comb groups (P<0.05). The results of this study indicate that combined therapies and endotoxemic status may alter the plasma pharmacokinetics of CS in calves.