Effect of pertussis toxin on calcium influx in three contraction models.

Pertussis toxin (PTX) blocks G protein activation and inhibits signal transmission from the activated receptor to effectors that are specific for the G protein-coupled receptor. The aim of the present study was to evaluate the effect of PTX on vascular smooth muscle cells that were stimulated pharmacologically with phenylephrine (α-adrenoceptor agonist), mastoparan-7 (direct G-protein activator) and Bay K8644 (direct calcium channel activator). The changes in perfusion pressure that were proportional to the degree of phenylephrine-induced constriction of rat tail arteries were assessed. Concentration-response curves (CRCs) that were obtained for phenylephrine, mastoparan-7 and Bay K8644 presented a sigmoidal association. A significantly reduced calcium influx to the cytoplasm in the presence of mastoparan-7 resulted in a significant rightward shift of the CRCs with a significant reduction in maximal responses. The presence of PTX did not change mastoparan-7 and Bay K8644-induced contraction, whereas the significant inhibition of phenylephrine-induced contraction was found. The results of the experiments indicated that PTX significantly inhibited phenylephrine-induced contraction of vascular smooth muscle cells by inhibition of calcium influx from the intra- and extracellular calcium space. PTX did not change the smooth muscle contraction that was induced by mastoparan-7 and Bay K8644. The predominant effect of mastoparan-7 may be associated with other binding sites as compared to the G-protein or PTX may bind to other sites than mastoparan-7.

[CD20 antigen of Hodgkin and Reed-Sternberg cells as possible prognostic factor in patients with Hodgkin's lymphoma--preliminary reports]. / Antygen CD20 komórek Hodgkina i Reed-Sternberga jako potencjalny czynnik prognostyczny u chorych na chloniaka Hodgkina--doniesienia wstepne.

UNLABELLED: THE AIM of the study was to asses the validity of CD20 expression on H-RS cells as independent prognostic factor in patients with Hodgkin's lymphoma. METHODS: 72 patients (44 men and 28 women) between 15 and 73 y.o. (av. 36,5 y.o) treated in the Department of Oncological Chemotherapy of Silesian Medical Academy (1992-2002) were included in the study. Tissue specimens were immunohistochemically stained with monoclonal antibodies for CD20. RESULTS: Analyzed group was classified according to histological subtype as follows: LP - n = 3, NS - n = 26, MC - n = 23, LR - n = 7 and LD - n = 13. Overall survival (OS) for the group was from 3 to 169 months (av. 64,5), disease free survival (DFS) - 4 to 167 months (av. 44,8) respectively. CD20 expression on H-RS cells was found in 13,9% subjects. Statistically significant difference (p = 0,0001) in DFS has been found between groups with and without CD20 expression. Results of this study are preliminary and should be confirmed in larger prospective studies.