In Vitro Influence of Mycophenolic Acid on Selected Parameters of Stimulated Peripheral Canine Lymphocytes.

Mycophenolic acid (MPA) is an active metabolite of mycophenolate mofetil, a new immunosuppressive drug effective in the treatment of canine autoimmune diseases. The impact of MPA on immunity is ambiguous and its influence on the canine immune system is unknown. The aim of the study was to determine markers of changes in stimulated peripheral canine lymphocytes after treatment with MPA in vitro. Twenty nine healthy dogs were studied. Phenotypic and functional analysis of lymphocytes was performed on peripheral blood mononuclear cells cultured with mitogens and different MPA concentrations- 1 μM (10(-3) mol/m(3)), 10 μM or 100 μM. Apoptotic cells were detected by Annexin V and 7-aminoactinomycin D (7-AAD). The expression of antigens (CD3, CD4, CD8, CD21, CD25, forkhead box P3 [FoxP3] and proliferating cell nuclear antigen [PCNA]) was assessed with monoclonal antibodies. The proliferation indices were analyzed in carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled cells. All analyses were performed using flow cytometry. The influence of MPA on apoptosis was dependent on the mechanism of cell activation and MPA concentration. MPA caused a decrease in the expression of lymphocyte surface antigens, CD3, CD8 and CD25. Its impact on the expression of CD4 and CD21 was negligible. Its negative influence on the expression of FoxP3 was dependent on cell stimulation. MPA inhibited lymphocyte proliferation. In conclusion, MPA inhibited the activity of stimulated canine lymphocytes by blocking lymphocyte activation and proliferation. The influence of MPA on the development of immune tolerance-expansion of Treg cells and lymphocyte apoptosis-was ambiguous and was dependent on the mechanism of cellular activation. The concentration that MPA reaches in the blood may lead to inhibition of the functions of the canine immune system. The applied panel of markers can be used for evaluation of the effects of immunosuppressive compounds in the dog

Movement patterns of Japanese fluvial sculpin Cottus pollux in a headwater stream

Movements of the Japanese fluvial sculpin Cottus pollux were studied over a 2-year period using a mark-recapture technique in two reaches (100 and 300 m) of a small, temperate stream system, the Fujii River, Japan. Of 321 recaptures, 62 fish (19.3%) moved across at least one riffle (i.e., were \u27mobile\u27). Fish moved distances of up to 192 in (median = 4 in). Distance moved (m) by all fish correlated positively with the recapture interval (d) in both years, illustrating the importance of the temporal dimension for movements. Mean daily distance moved (m/d) in the high-flow year was greater than that in the low-flow year. The high-flow year, which had a higher frequency of peak flow events, had a higher frequency of mobile fish than did the low-flow year, suggesting that interannual variation in movements is related to streamflow. Fish size and growth did not differ between mobile fish and residents in the high-flow year; however, mobile fish were larger and grew more slowly than residents in the low-flow year. Patterns of movement from multiple recaptures showed evidence for round-trip movements at channel unit and reach scales, but no fish completed round-trip movements by crossing a small weir (\u3c 0.5 m in height). These results emphasize the importance of maintaining fish passage and pool-riffle sequences throughout the stream course to prevent isolation of subpopulations by weirs, culverts, and road crossings. Physical barriers to Japanese fluvial sculpin movements could be mitigated by placing a ramp of cobbles downstream of the barrier