Reciprocal relationship between methylation status and loss of heterozygosity at the p14 (ARF) locus in Australian and South African hepatocellular carcinomas

Chromosome 9p21, a locus comprising the tumor suppressor genes (TSG) p16(INK4) (a) and p14(ARF) , is a common region of loss of heterozygosity (LOH) in hepatocellular carcinoma (HCC). p14(ARF) shares exon 2 with p16 in a different reading frame. p14 binds to MDM2 resulting in a stabilization of functional p53 . This study examined the roles of p14, p16 and p53 in hepatocarcinogenesis, in 37 Australian and 24 South African patients. LOH at 9p21 and 17p13.1, p14 and p16 mutation analysis, p14 and p16 promoter methylation and p14, p16 and p53 protein expression was examined. LOH at 9p21 was detected more frequently in South African HCC (P = 0.04). Comparable rates of p53 LOH were observed in Australian and South African HCC (10/22, 45%vs 13/22, 59%, respectively). Hypermethylation of the p14 promoter was more prevalent in Australian HCC than in South African HCC (17/37, 46%vs 7/24, 29%, respectively). In Australian HCC the prevalence of p14 methylation increased with age (P = 0.03). p16 promoter methylation was observed in 12/37 (32%) and 6/24 (25%) in Australian and South African HCC, respectively. Loss of p16 protein expression was detected in 14/36 Australian HCC whereas p53 protein expression was detected in 9/36. Significantly, a reciprocal relationship between 9p21 LOH and p14 promoter hypermethylation was observed (P less than or equal to0.05 ). No significant association between p14 and p53 was seen in this study. The reciprocal relationship identified indicates different pathways of tumorigenesis and likely reflects different etiologies of HCC in the two countries. (C) 2002 Blackwell Science Asia Pty Ltd.

On learning context-free and context-sensitive languages

The long short-term memory (LSTM) is not the only neural network which learns a context sensitive language. Second-order sequential cascaded networks (SCNs) are able to induce means from a finite fragment of a context-sensitive language for processing strings outside the training set. The dynamical behavior of the SCN is qualitatively distinct from that observed in LSTM networks. Differences in performance and dynamics are discussed.

Writing the body of the mother: Narrative moments in Tsushima Yuko, Ariyoshi Sawako and Enchi Fumiko

This discussion argues the transformative potential inherent in the corporeal experience of motherhood as represented in selected textual moments of Japanese narrative. Narratives that address the experiences of the body of the mother are informed and given substance by an intense physicality, and thus have the potential to contest processes of social inscription in addition to suggesting alternative possibilities for all readers, not just those occupying an embodied maternal space. The discussion features brief events from the work of three writers who have written as mothers: Tsushima Y(u)macrko, Ariyoshi Sawako and Enchi Fumiko. In Yama o hashiru onna (1980; translated as Woman Running in the Mountains, 1991), Tsushima Y(u)macrko invites the reader to consider the embodied response to light of Takiko, a young pregnant woman. Emiko, the protagonist of Hishoku (Without Colour, 1967) by Ariyoshi Sawako, is the Japanese wife of an African American and has just given birth to a child. The daughter protagonist in Enchi Fumiko's 'Kami' ('Hair', 1957) operates a hairdressing business that is viable only with her mother's unpaid labour. The narratives are read through a matrix of post-structuralist theories of embodiment, drawing on the work of writers such as Julia Kristeva, Luce Irigaray and Elizabeth Grosz.