The occurrence and significance of triploidy in the liver fluke, Fasciola hepatica.

Karyotyping of Fasciola hepatica samples from Britain and Ireland has identified a triploid isolate which is effectively aspermic, rendering it necessarily asexually reproducing. Considering the extensive presence of asexually reproducing diploid and triploid Fasciola in Asia it is suggested that facultative gynogenesis is widespread in this parasite. This has important implications for the population genetics and evolution of Fasciola, especially in relation to the development and spread of drug resistance, and must be considered in the mathematical modelling of this process.

Fyn kinase initiates complementary signals required for IgE-dependent mast cell degranulation

FcRI activation of mast cells is thought to involve Lyn and Syk kinases proximal to the receptor and the signaling complex organized by the linker for activation of T cells (LAT). We report here that FcRI also uses a Fyn kinase-dependent pathway that does not require Lyn kinase or the adapter LAT for its initiation, but is necessary for mast cell degranulation. Lyn-deficiency enhanced Fyn-dependent signals and degranulation, but inhibited the calcium response. Fyn-deficiency impaired degranulation, whereas Lyn-mediated signaling and calcium was normal. Thus, FcRI-dependent mast cell degranulation involves cross-talk between Fyn and Lyn kinases.

Interleukin 18 promoter polymorphisms are not strongly associated with type 1 diabetes in a UK population

Interleukin 18 (IL18) is a proinflammatory cytokine whose levels are increased in the subclinical stage of insulin-dependent (type I) diabetes mellitus. Previous case-control studies have reported associations between IL18 -607C>A and -137G>C promoter polymorphisms and type I diabetes. We performed case-control and family-based association studies employing Pyrosequencing to assess if these IL18 polymorphisms are also associated with the development of type I diabetes in the Northern Ireland population. The chi2 analysis of genotype and allele frequencies for the IL18 polymorphisms in cases (n=433) vs controls (n=426) revealed no significant differences (P>0.05). Assessment of allele transmission distortion from informative parents to affected offspring also failed to confirm previously reported associations. Stratification of these analyses for age-at-onset and HLA-DR type did not reveal any significance associations. In conclusion, our data do not support the strong positive associations of IL18 promoter polymorphisms with type I diabetes reported in previous smaller studies.

The regulation and role of osteopontin in malignant transformation and cancer.

Osteopontin (OPN) is a predominantly secreted extracellular matrix glycophosphoprotein which binds to alpha v-containing integrins and has an important role in malignant cell attachment and invasion. High OPN expression in the primary tumor is associated with early metastasis and poor outcome in human breast and other cancers. Forced OPN overexpression in benign cells may induce neoplastic-like cell behaviour including increased attachment and invasion in vitro as well as the ability to metastasize in vivo. Conversely, OPN inhibition by antisense cDNA impedes cell growth and tumor forming capacity. OPN is not mutationally activated in cancer but its expression is regulated by Wnt/Tcf signaling, steroid receptors, growth factors, ras, Ets and AP-1 transcription factors. Presumably these factors are implicated in induction of OPN overexpression in cancer. Greater understanding of the role of OPN in neoplastic change and its transcriptional regulation may enable development of novel cancer treatment strategies