The pathobiology of the septin gene family.

Septins are an evolutionarily conserved group of GTP-binding and filament-forming proteins that belong to the large superclass of P-loop GTPases. While originally discovered in yeast as cell division cycle mutants with cytokinesis defects, they are now known to have diverse cellular roles which include polarity determination, cytoskeletal reorganization, membrane dynamics, vesicle trafficking, and exocytosis. Septin proteins form homo- and hetero-oligomeric polymers which can assemble into higher-order filaments. They are also known to interact with components of the cytoskeleton, ie actin and tubulin. The precise role of GTP binding is not clear but a current model suggests that it is associated with conformational changes which alter binding to other proteins. There are at least 12 human septin genes, and although information on expression patterns is limited, most undergo complex alternative splicing with some degree of tissue specificity. Nevertheless, an increasing body of data implicates the septin family in the pathogenesis of diverse disease states including neoplasia, neurodegenerative conditions, and infections. Here the known biochemical properties of mammalian septins are reviewed in the light of the data from yeast and other model organisms. The data implicating septins in human disease are considered and a model linking these data is proposed. It is posited that septins can act as regulatable scaffolds where the stoichiometry of septin associations, modifications, GTP status, and the interactions with other proteins allow the regulation of key cellular processes including polarity determination. Derangements of such septin scaffolds thus explain the role of septins in disease states. Copyright © 2004 Pathological Society of Great Britain and Ireland.

Cyclooxygenase-2 expression correlates with phaeochromocytoma malignancy.

Abstract Aims: Phaeochromocytomas are rare but potentially life-threatening neuroendocrine tumours of the adrenal medulla or sympathetic nervous system ganglia. There are no histological features which reliably differentiate benign from malignant phaeochromocytomas. The current study evaluated cyclooxygenase-2 (Cox-2) and Bcl-2 as tissue-based biomarkers of phaeochromocytoma prognosis. Methods and Results: Cox-2 and Bcl-2 expression were examined immunohistochemically in tissue from forty-one sporadic phaeochromocytoma patients followed up for a minimum of five years after diagnosis. There was a statistically significant association between Cox-2 histoscore (intensity x porportion) and the development of tumour recurrence or metastases (p=0.006). A significant relationship between the co-expression of Cox-2 and Bcl-2 in the primary tumour and the presence of recurrent disease was observed (p=0.034). A highly significant association was observed between, (i) the tumour-associated expression of these two oncoproteins (p=0.001) and, (ii) Cox-2 histoscore and the presence of Bcl-2 expression (p=0.002). Cox regression analysis demonstrated no significant relationship between, (i) the presence or absence of either Cox-2 or Bcl-2 and patient survival or, (ii) between Cox-2 histoscore and patient survival. Conclusions: These results suggest that Cox-2 and Bcl-2 may promote phaeochromocytoma malignancy and that these oncoproteins may be valuable surrogate markers of an aggressive tumour phenotype.

Mentally disordered offenders and the European Court of Human Rights

This article presents the findings from a study of cases taken to the European Court of Human Rights by mentally disordered offenders. The issues raised include the problems raised by indeterminate sentences, the use of detention for preventive purposes, and debates about treatment. The countries represented are Belgium, Norway, Poland, the Netherlands, Russia and the United Kingdom.