Quantitative and qualitative changes of serum proteins, apart from glycation, have not been sufficiently studied in streptozotocin-induced diabetic rats (D), the most common experimental model for diabetes. Thus, we decided to analyze the serum of diabetic rats by concanavalin A-blotting in comparison with rats with acute inflammation induced by fermented yeast (Y), in which characteristic alterations of serum proteins have been described. Two months after the streptozotocin treatment, the blood glucose levels were highly elevated (456± 24 vs. 124± 10 mg/dl, p<0.001, n=12), the body weight was significantly lower than normal (279± 10 vs. 392± 6 g, p<0.001, n=12), and serum proteins appeared to be highly glycated (p<0.001) when analyzed by the fructosamine assay, without any significant change in the total serum protein concentration. Analysis by concanavalin A-blotting, revealed a significant decrease of a1-inhibitor-3 (a1-I3, p<0.05) and an increase of the b chain of haptoglobin (b-Hp, p<0.05) in both D and Y rats (n=3) compared with control animals. However, acute inflammation caused a marked rise of two prominent acute phase proteins, a2-macroglobulin and hemopexin, which did not change appreciably in diabetic rats. Further work will be necessary to evaluate the physiopathological significance of these phenomena which could result from changes of both concentration and glycosylation of the aforementioned proteins., L. Saso, P. Tommasino, G. Italiano, E. Grippa, M.G. Leone, M.T. Gatto, B. Silvestrini., and Obsahuje bibliografii
The biology of sialic acids has been an object of interest in many models of acquired and inherited skeletal muscle pathology. The present study focuses on the sialylation changes in mouse skeletal muscle after invasion by the parasitic nematode Trichinella spiralis (Owen, 1835). Asynchronous infection with T. spiralis was induced in mice that were sacrificed at different time points of the muscle phase of the disease. The amounts of free sialic acid, sialylated glycoproteins and total sialyltransferase activity were quantified. Histochemistry with lectins specific for sialic acid was performed in order to localise distribution of sialylated glycoconjugates and to clarify the type of linkage of the sialic acid residues on the carbohydrate chains. Elevated intracellular accumulation of α-2,3- and α-2,6-sialylated glycoconjugates was found only within the affected sarcoplasm of muscle fibres invaded by the parasite. The levels of free and protein-bound sialic acid were increased and the total sialyltransferase activity was also elevated in the skeletal muscle tissue of animals with trichinellosis. We suggest that the biological significance of this phenomenon might be associated with securing integrity of the newly formed nurse cell within the surrounding healthy skeletal muscle tissue. The increased sialylation might inhibit the affected muscle cell contractility through decreased membrane ion gating, helping the parasite accommodation process., Rositsa Milcheva, Dimitar Ivanov, Ivan Iliev, Russy Russev, Svetlozara Petkova, Pavel Babál., and Obsahuje bibliografii