ABSTRACT:The QT interval has been the objective of exhaustive attention in the past and also in recent times. A number of conditions, congenital and acquired, can have a direct effect on cardiac repolarization. Also drug regulatory agencies have showed increasing interest in the topic because certain drugs can prolong the QT interval to a level that produces ventricular arrhythmias. The dog is a species that shares some similarities with the human electrical system and has been used in human and veterinary research. We here present the current recommendations for QT measurement in dogs for use in clinical and experimental practice.

Natural substances offer interesting bioactivity patterns including antiproliferative, antioxidant or cytotoxic effects. However, the safety profile of many of them has not been extensively determined. In this study, the cytotoxic effect of Aeruginosin-865, resveratrol and capsaicin at different concentrations was tested on normal mouse cells (NIH/3T3) and tumour fibroblasts (WEHI-13VAR) as well as on liver-and kidney-derived cells from fallow deer. A lactate dehydrogenase cytotoxicity assay kit was used to measure cell death in response to treatment with the test substances. It was found that NIH/3T3 cells tolerated Aeruginosin-865 (10-200 M) and resveratrol (5-100 M) treatment without any cytotoxic effect, while capsaicin exerted a cytotoxic effect only at the highest tested concentration (200 M). Mouse fibrosarcoma cells were more sensitive to the cytotoxic effect of all three compounds where Aeruginosin-865 (100-200 M) and resveratrol (50-100 M) showed high-dose cytotoxicity and capsaicin showed low-and high-dose cytotoxicity (25 M and 200 M). The three tested compounds at the highest concentrations were found to be cytotoxic to both liver-and kidney-derived cells from fallow deer. Overall, the results indicate that the cytotoxic effects of the three tested natural substances on cells derived from fallow deer and mouse tumour fibroblasts differ significantly from those exerted on normal fibroblasts. The results demonstrate the potential of these natural compounds as therapeutic agents and pave the way for future in vivo toxicological investigations.

ABSTRACT:The objective of this study was to determine ranges of haematological and biochemical parameters of Przewalski horses (Equus przewalski) kept in the Czech Republic, to compare the results with data reported for the same species as well as for domestic horses (Equus caballus), and to evaluate differences between both genders and age groups. Stallions showed significantly higher counts of red blood cells and bands, higher levels of total bilirubin and magnesium, and a higher activity of GGT. Higher concentrations of cholesterol, vitamin A and sodium were found in mares. Young animals were characterised by a lower count of eosinophilic granulocytes, a higher activity of ALP and higher concentrations of calcium, inorganic phosphorus, sodium and creatinine. Other differences were not significant.

The aim of this study was to determine the maximum tolerated dose and the haematological and non-haematological toxicity of chlorambucil in male Wistar rats. Chlorambucil (pulverized pills or pure substance) was dissolved in ethanol and administered orally at a dose ranging from 0.15 to 50 mg/kg/day for 5 days.evaluations of experimental rats included general clinical state of health, body weight, haematological indicators (red blood cell count, white blood cell count, platelet count, differential leukocyte count, packed cell volume and haemoglobin concentration), biochemical plasma indicators (urea, creatinine, AlP, AlT, AST, na, K, Cl), immunophenotype of leukocytes (Cd3, Cd8 and Cd4 markers), as well as histopathology.Doses of chlorambucil from 0.15 to 0.75 mg/kg/day had no effect on the general clinical state of health as well as on other laboratory variables. Doses of 2-12 mg/kg/day were well tolerated, but mild myelotoxicity (leukopaenia) and elevated activities of liver transaminases were found. Doses of 20 to 50 mg/kg/day were myelotoxic (p < 0.01) with prevailing lymphopaenia but only minimum effects on red blood cells and platelets. Histology revealed pneumotoxicity, nephrotoxicity and damage to the gastrointestinal tract. Doses of 40 and 50 mg/kg/day resulted in acute lethal effects in 50% and 75% of individuals, respectively.Results of this study are intended for use in the testing of chlorambucil in combination with other drugs as a conditioning for bone marrow transplantation.Haematological toxicity, non-haematological toxicity, acute lethal effect, Leukeran, blood cells, anti-cancer therapy

The effect of enrofloxacin on the QT interval of the electrocardiogram was studied in 30 hospitalized dogs. The experimental group (n = 15) received enrofloxacin parenterally (subcutaneously) at a dose of 5 mg/kg twice daily and amoxicillin-clavulanate intravenously at a dose of 22 mg/kg three times daily. The control group (n = 15) received only amoxicillinclavulanate. Electrocardiography was carried out for 5 min once daily for 6 days. The QT interval was corrected by four different formulae. No differences were found between the two groups or within each group for the duration of the study. On the last day of the study the average QT interval for the control and experimental groups was 213.2 ms and 202.9 ms, respectively. Enrofloxacin did not cause prolongation of the QT or corrected QT intervals. We can conclude that the parenteral administration of enrofloxacin in non-cardiac dogs does not adversely affect the electrocardiographic indicators (no prolongation of the QT or corrected QT interval) and does not induce ventricular arrhythmias. Parenteral use of enrofloxacin is thus safe and effective in non-cardiac dogs.