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

Origin and fate of methane in the Eastern Tropical North Pacific oxygen minimum zone

This work was funded by the Natural Environment Research Council (grant NE/E01559X/1)

Mini tunelizador moldável: um avanço técnico no acesso vascular para hemodiálise Mini moldable tunneler: a technical improvement for hemodialysis access

CONTEXTO: A confecção de fístula para hemodiálise pode envolver a criação de túnel para a acomodação do enxerto - veia autóloga ou prótese sintética. O trajeto e a extensão dependem do local escolhido para a realização das anastomoses e posicionamento do trajeto do enxerto. Na atualidade, os tunelizadores utilizados são constituídos de estruturas cilíndricas metálicas rígidas, que tornam necessário o uso de múltiplos tamanhos e conformações. OBJETIVO: Testar a utilização de um único mini tunelizador universal metálico e moldável na cirurgia de confecção de fístula para hemodiálise. MÉTODOS: Trata-se de um estudo piloto. O tunelizador desenvolvido consiste de uma estrutura cilíndrica e modular composta de fio de aço inoxidável moldável interno, com manopla em extremidade proximal e dupla ponta cônica intercambiável em extremidade distal e bainha cilíndrica externa de polietileno. O tunelizador foi utilizado em dez cirurgias de confecção de fístulas para hemodiálise em membros superiores e inferiores, e o sucesso de sua aplicabilidade e a frequência de complicações precoces foram observados. RESULTADOS: Suas características de maleabilidade e conformibilidade permitiram a utilização do mesmo tunelizador nos diversos tipos de fístulas realizadas. A ponta cônica distal com duplo diâmetro, intercambiável, permitiu que o mesmo aparato fosse aplicado na utilização de veia autógena ou prótese sintética. Todas as cirurgias foram seguidas de sucesso e com baixos índices de complicações precoces. CONCLUSÃO: A versatilidade do mini tunelizador metálico maleável e moldável permitiu sua utilização em todas as fístulas realizadas, independentemente do sítio das anastomoses e o trajeto de acomodação escolhido, sem complicações e com excelente índice de perviedade. Os dados sugerem que o mini tunelizador metálico maleável moldável pode ser utilizado com segurança e vantagens nas cirurgias de confecção de fístula para hemodiálise. Sua versatilidade e baixo custo de produção podem levá-lo a substituir os tunelizadores rígidos utilizados na atualidade e apontam para estudos mais elaborados e com casuística adequada para avaliação do real valor do novo instrumento.<br>BACKGROUND: Hemodialysis access fistula may involve creation of a tunnel for the accommodation of autologous vein or synthetic graft. The route and extent depend on the location of the anastomosis and fistula body.Currently, the tunnelers used are rigid metallic cylindrical structures. Various sizes and conformations may be necessary. OBJECTIVE: Testing the use of a mini universal moldable tunnel maker in hemodialysis access fistula surgical creation. METHODS: This is a pilot study. The tunneler developed consists of a cylindrical structure composed of stainless steel wire with a handle at the proximal end and dual interchangeable conical tip at the distal end. It is covered with a cylindrical sheath of polyethylene. Its technical surgical application and complications were studied during ten hemodialysis fistula creation. RESULTS: Characteristics of flexibility and conformability made possible the same mini tunnel maker to be used in various types of fistulas performed. The tapered distal tip with double diameter, interchangeable head, allowed the same apparatus to be used in autogenos and graft fistulas surgical creation. CONCLUSION: The same mini malleable tunneler was used in all fistulas, regardless of the site of anastomosis and type of fistula performed without complications and with excellent patency rate

Narrative, memory and social representations: a conversation between history and social psychology

This paper explores relations between narrative, memory and social representations by examining how social representations express the ways in which communities deal with the historical past. Drawing on a case study of social representations of the Brazilian public sphere, it shows how a specific narrative of origins re-invents history as a useful mythological resource for defending identity, building inter-group solidarity and maintaining social cohesion. Produced by a time-travelling dialogue between multiple sources, this historical narrative is functional both to transform, to stabilise and give resilience to specific social representations of public life. The Brazilian case shows that historical narratives, which tend to be considered as part of the stable core of representational fields, are neither homogenous nor consensual but open polyphasic platforms for the construction of alternative, often contradictory, representations. These representations do not go away because they are ever changing and situated, recruit multiple ways of thinking and fulfil functions of identity, inter-group solidarity and social cohesion. In the disjunction between historiography and the past as social representation are the challenges and opportunities for the dialogue between historians and social psychologists