In the dog, creatine kinase (CK) is mostly present in the skeletal muscles, myocardium, brain and intestine. The MM isoenzyme predominates in muscles and myocardium. In plasma, reference values depend on the technique used and CK-MB accounts for about 30-45% of total CK activity. Sex has no influence on plasma CK activity, which is higher in young dogs than in adults. Plasma CK is elevated after physical exercise. After its release from the cells, CK reaches the plasma mostly via the lymphatic route and then remains in the plasma compartment. It is rapidly cleared with a half-life of about 2 hours. Muscle diseases are the main source of plasma CK elevations: inherited myopathies, malignant hyperthermia, hypothyroidism, vitamin E-selenium deficiency, prolonged decubitus, intramuscular injections, surgery, etc. Plasma CK is also increased in experimental myocardial infarction, for which the dog is an interesting model, allowing quantification of the damage by measuring the total CK activity released.

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Acute respiratory distress syndrome (ARDS) is a fatal disease that includes inflammation formed by septic and non-septic causes. Reactive oxygen radicals (ROS) play a key role in ARDS pathophysiology and constitute the base of damage process. Antioxidant vitamins are used for inhibiting hazardous effects of radicals. Therefore, effects of antioxidant vitamins such as α-lipoic acid (ALA), vitamin E (VITE), and C (VITC) were investigated on oleic acid (OA)-induced ARDS rat model. Furthermore, high and low dose of methylprednisolone (HDMP, LDMP) was used for comparing effects of the vitamins. In this study, 42 male rats were divided to seven groups named control, OA, ALA, VITE, VITC, LDMP, and HDMP. OA was intravenously administered to all groups except control group and other compounds were orally administered (ALA, VITE, and VITC: 100 mg/kg, LDMP: 5 mg/kg, HDMP: 50 mg/kg) after OA injections. OA increased MDA level in lung tissue and TNF-α and IL-1β cytokine levels in serum. ALA, VITE, VITC, and both dose of MP significantly decreased the cytokine levels. Although OA reduced SOD, CAT, and GSH levels in lung tissue, the vitamins and LDMP markedly enhanced the levels except for HDMP. Furthermore, OA showed thickening in bronchi and alveolar septum, hyperemia in vessels, and inflammatory cell infiltrations in lung tissue histopathological examinations. Antioxidant vitamins may be useful for premedication of ARDS and similar disorders. However, methylprednisolone was not found sufficient for being a therapeutic agent for ARDS.

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The fate of skeletal muscle-derived creatine kinase (CK) was investigated in six dogs. After i.m. and i.v. injections of 3000 g and 105,000 g supernatants of dog muscle homogenates, plasma CK activity was measured up to 48 h. There was no significant difference in pharmacokinetic parameters dependent on the type of supernatant injected. After i.v. injection, the volume of distribution of CK was equal to the plasma volume, CK clearance was relatively low (about 0.5 mL/kg/min) and its terminal half-life of elimination was about 2.5 h. After i.m. injection, the CK terminal half-life was about 6.5 h, demonstrating a flip-flop mechanism, i.e. a limiting absorption process from the site of injection. Bioavailability after i.m. injection was about 65%, and the rate of absorption from muscle injection site was relatively slow: peak activity occurred at the second hour post administration, and most CK activity had been absorbed by 24 h. These pharmacokinetic parameters can be used as a basis for a minimally invasive means of quantitating muscle damage either after intramuscular drug administration or in canine sports medicine.

Purpose Pentoxifylline (PTX) is a derivative of methylxanthine and is used in peripheral vascular and cerebrovascular diseases for its effect on the regulation of blood circulation. We investigated whether PTX could be beneficial for femoral head osteonecrosis associated with steroid through these effects. Methods Sixty mature Leghorn type chickens were chosen and divided into three groups. The 25 chickens in group A were given a weekly dose of 3 mg/kg/week methylprednisolone acetate intramuscularly. Four chickens in group B died after the first drug injection and were excluded from the study. Therefore, the remaining 21 chickens in group B were additionally given 25 mg/kg/day pentoxifylline intramuscularly, along with the steroid medication as given in group A. The ten chickens in group C were not given any injections, as they were accepted as the control group. After the sacrifice of the animals at week 14, both femoral heads were taken from each animal. The animals which died along the course of the study also underwent pathological examination but were not a part of the statistical analysis. Results In this study, steroid induced femoral head osteonecrosis has been experimentally observed in chickens after high doses of corticosteroid therapy. The chickens were given pentoxifylline in order to prevent the effects of steroid on bones and bone marrow. The results showed that chickens are suitable osteonecrosis models, and that steroid causes adipogenesis and necrosis in the bone marrow and the death of the subchondral bone. Conclusions The results of this study hint at the assumption that PTX may have a positive benefit on ONFH. PTX seems to minimise the effects of the steroid and reduce the incidence of ONFH.

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