Contact between Mesocestoides vogae tetrathyridia induces their division.

Mesocestoides vogae is a cestode of the order Cyclophyllidea, and its second intermediate hosts are mammals, birds, amphibians, and reptiles. The parasite forms a tetrathyridium in the second intermediate host and multiplies asexually, sometimes to the point of filling the host's abdominal cavity. Proliferated tetrathyridium may cause lethal conditions in the host. During the asexual multiplication period, the scolex first replicates into two and then divides into two worms. In this study, to investigate the factors that promote the replication, tetrathyridia were cultured under various in vitro conditions. When several worms which already had two scolexes were cultured together, the division into two worm bodies was complete, but when single worm was cultured, the division hardly proceeded. The result indicates that the division progression of tetrathyridia with two scolexes requires the presence of other worms. In contrast, tetrathyridia with only one scolex did not initiate the division process, whether cultured together or alone. Then, the necessity of direct contact between the bodies of the worms to promote the division of tetrathyridia with two scolexes was assessed. For this, the well of the culture plate was partitioned into upper and lower parts using a mesh, and 20 worms in the upper part and single worm in the lower part were cultured. In all examined wells, worms in the upper part showed complete division, whereas the worms in the lower part rarely completed the division. Thus, direct contact between tetrathyridium promotes the division of tetrathyridia bearing two scolexes.

Effect of age, sex, and breed on serum cystatin C and creatinine concentrations in dogs.

This study investigated the effects of age, sex and breed on serum cystatin C (Cys-C) and creatinine in small breed dogs. This retrospective study included 250 dogs weighing less than 15 kg without azotemia. Serum Cys-C and creatinine concentrations were analyzed, along with their correlation with age, and the difference between sexes or dog breeds. Serum Cys-C concentration correlated with age (P < 0.001), and did not differ between sexes or dog breeds. By contrast, serum creatinine concentration did not correlate with age. Serum creatinine concentration was higher in males than females (P < 0.05), and was lower in Miniature Dachshunds and Chihuahuas, and was higher in Shiba Inus compared to the general study population (P < 0.001). Serum Cys-C concentration correlates with age, and might be more sensitive to aging-associated subclinical renal dysfunction than serum creatinine concentration in dogs. Unlike serum creatinine concentration, serum Cys-C concentration is not affected by sex or dog breed.