Training-induced changes in clotting parameters of athletic horses

The purpose of this study was to investigate the effects of training on prothrombin time, activated partial thromboplastin time, and fibrinogen (Fb) concentrations in horses to assess potential adaptive response to training. Fifteen clinically healthy horses were enrolled in the present study and equally divided into three groups. Group A completed an intense training program, group B participated in a light training program, and group C included sedentary horses. After 5 weeks, group B was subjected to the same training program completed by group A and renamed group B1. Blood samples were collected by jugular venipuncture from each animal at rest and analyzed within 2 h after sampling. A two-way ANOVA for repeated measures showed a significant effect of training (p < 0.05) on Fb concentrations in group B1 alone during the first week after changing the training program. Our findings demonstrated that Fb is a parameter susceptible to training. Fb plasma levels increase with a more intense training program. However, Fb plasma levels decreased after the first week and returned to basel levels, suggesting that the horses had adapted to the new training program.

Effects of hydrocortisone and aminophylline on the aggregation of equine platelets in vitro

The purpose of this study was to evaluate in vitro the effects of hydrocortisone and aminophylline on adenosine diphosphate (ADP)-induced platelet aggregation in horses. Blood samples from 30 healthy Thoroughbred horses were collected by via jugular venipuncture to assess platelet aggregation. Platelet-rich and platelet-poor plasma were prepared from all samples by centrifugation and divided into three different aliquots. In the first aliquot, platelet aggregation was measured after platelet activation with 1 microM and 0.5 microM ADP (Group A). In the other two aliquots, the effect of a 10 min preincubation with hydrocortisone (Group B) or aminophylline (Group C) on ADP-induced aggregation at final ADP concentrations of 1 microM and 0.5 microM was observed. Platelet aggregation, recorded by an aggregometer, was evaluated by measuring the maximum degree of platelet aggregation and the initial velocities of platelet aggregation were obtained. Our results demonstrated the inhibitory effect of hydrocortisone and the induction effect of aminophylline on equine platelet responses in vitro.

Effect of storage conditions on prothrombin time, activated partial thromboplastin time and fibrinogen concentration on canine plasma samples

The present study was to assess the effect of storage conditions on prothrombin time (PT), activated partial thromboplastin time (aPTT) and fibrinogen concentration in blood samples of healthy dogs. Thirty-five dogs of various breeds were included in the study. Citrated blood samples were obtained and plasma was divided into four aliquots to assess selected clotting parameters by means of a coagulometer. The first aliquot was analysed within 1 h after collection, while the remaining 3 were stored at 8degrees C for 4, 8 and 24 h, respectively. One-way repeated measures analysis of variance documented a significant decreasing effect on PT at 24 h compared to 8 h and on fibrinogen concentration after 8 and 24 h compared to sampling time and at 4 and 24 h compared to 8 h post sampling. In conclusion, the results of this study indicate that only fibrinogen appears prone to significant decrease. In fact, aPTT is not substantially affected by refrigeration for at least 24 h post sampling and PT showed a statistical difference that does not necessary indicate biological significance as the results obtained were within reference intervals for the dog.

Peripheral serotoninergic response to physical exercise in athletic horses

The purpose of this study was to evaluate the influence of exercise on plasma tryptophan (TRP) and free serotonin (f5-HT), whole blood-5-HT (WB-5-HT) and f5-HT/WB-5-HT ratio in Italian Saddle horses. Six clinically healthy Italian Saddle horses were subjected to a 450 meters obstacles course. Blood samples were collected from each horse by jugular venipuncture using vacutainer tubes with K3-EDTA at rest, immediately after exercise, and after 30 min. TRP, f5-HT and WB-5-HT were analyzed by HPLC. Immediately after exercise, statistically significant increases of f5-HT (p<0.001) and WB-5-HT (p<0.001) were observed. After 30 min, f5-HT and WB-5-HT decreased compared to immediately after exercise, but were still significantly higher than rest values (p<0.01 and p<0.05, respectively). A significant linear regression between f5-HT and WB-5-HT was observed during experimental conditions. f5-HT and WB-5-HT modifications after exercise suggest an important role of peripheral serotoninergic markers in response to physical activity. The possible source of extra serotonin detected after show jumping should be clarified by further investigation.

Effects of different electromagnetic fields on circadian rhythms of some haematochemical parameters in rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the effects of different electromagnetic fields on some haematochemical parameters of circadian rhythms in Sprague-Dawley rats.</p><p><b>METHODS</b>The study was carried out in 18 male and 18 female rats in good health conditions exposed to 50 Hz magnetic sinusoid fields at the intensity of 1000 microT, 100 microT, and 0 microT (control group) respectively, and in 18 male and 18 female rats in good health conditions exposed to 1.8 GHz electromagnetic fields at the intensity of 50 V/m, 25 V/m and 0 V/m (control group), respectively. Following haematochemical parameters for glucose, triglycerides, and total cholesterol were measured.</p><p><b>RESULTS</b>Different effects of electromagnetic fields on circadian rhythms of both male and female rats were observed. Different changes occurred in some haematochemical parameters for glucose, triglycerides, and total cholesterol (P < 0.05).</p><p><b>CONCLUSION</b>Exposure to different electromagnetic fields is responsible for the variations of some haematochemical parameters in rats.</p>

Effects of exposure to extremely low frequency electro-magnetic fields on circadian rhythms and distribution of some leukocyte differentiation antigens in dairy cows / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the effects of extremely low frequency magnetic and electric fields (ELFEMFs) emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows.</p><p><b>METHODS</b>The study was carried out in 5 cows exposed to 1.98-3.28 microT of ELFEMFs and in 5 control cows exposed to 0.2-0.7 microT of ELFEMFs. Following haematological and immunologic parameters were measured in both groups: WBC, CD45R, CD6, CD4, CD8, CD21, and CD11B leukocyte antigen expression.</p><p><b>RESULTS</b>Some of the haematological and immunologic parameters under investigation were similar in both groups. However, CD8 (T lymphocyte surface antigen) was higher in the exposed group (1.35 +/- 0.120 vs. 0.50 +/- 0.14 x 10(3)/mL). Furthermore, the CD4/CD8 ratio (0.84 +/- 0.05 and 2.19 +/- 0.16 for exposed and not exposed cows respectively) and circadian rhythm were different between the two groups.</p><p><b>CONCLUSION</b>Exposure to ELFEMFs is responsible of the abnormal temporal variations and distribution of some haematological and immunological parameters in dairy cows.</p>

Echocardiography and electrocardiography as means to evaluate potential performance in horses

Prediction of potential performance is one of the goals of exercise physiology investigations. When Selecting a horse for competition, one of the main objectives is to choose the one that predictably will reveal a competitive aptitude above the average. The horses used in this study underwent a two-dimensional echocardiography study and a conventional 3 leads electrocardiogram. The results show that heart score is not an appropriate index to evaluate the heart size in the horse. On the other hand, there are currently more suitable and accurate procedures such as echocardiography that allow performing a clear anatomical evaluation and accurate measurement in order to calculate LVMM and to predict performance.