The human keratins: biology and pathology

The keratins are the typical intermediate filament proteins of epithelia, showing an outstanding degree of molecular diversity. Heteropolymeric filaments are formed by pairing of type I and type II molecules. In humans 54 functional keratin genes exist. They are expressed in highly specific patterns related to the epithelial type and stage of cellular differentiation. About half of all keratins—including numerous keratins characterized only recently—are restricted to the various compartments of hair follicles. As part of the epithelial cytoskeleton, keratins are important for the mechanical stability and integrity of epithelial cells and tissues. Moreover, some keratins also have regulatory functions and are involved in intracellular signaling pathways, e.g. protection from stress, wound healing, and apoptosis. Applying the new consensus nomenclature, this article summarizes, for all human keratins, their cell type and tissue distribution and their functional significance in relation to transgenic mouse models and human hereditary keratin diseases. Furthermore, since keratins also exhibit characteristic expression patterns in human tumors, several of them (notably K5, K7, K8/K18, K19, and K20) have great importance in immunohistochemical tumor diagnosis of carcinomas, in particular of unclear metastases and in precise classification and subtyping. Future research might open further fields of clinical application for this remarkable protein family

Examining geographic and occupational mobility: A loglinear modelling approach

This article attempts to develop a set of loglinear models that synthesise gravity models of interregional mobility and loglinear models of occupational mobility. The development of the model is progressed from a simple two-way mobility table analysis to a three-way analysis that controls for one aspect of mobility while investigating another and eventually to a four-way analysis that simultaneously assesses the joint effect of occupational and geographic mobility. An example based on data from the 1970 United States census demonstrates that the models can effectively capture the joint effect of occupational and geographic mobility. The results show that interregional movers may not necessarily have strong occupational persistence. With regard to female dominated clerical occupations, interregional migration is positively associated with upward occupational mobility, and the propensity for upward mobility was consistently greater for males than for females. Copyright (c) 2006 the author(s). Journal compilation (c) 2006 RSAI.