Intermediate filament cytoskeleton of the liver in health and disease

Intermediate filaments (IFs) represent the largest cytoskeletal gene family comprising ~70 genes expressed in tissue specific manner. In addition to scaffolding function, they form complex signaling platforms and interact with various kinases, adaptor, and apoptotic proteins. IFs are established cytoprotectants and IF variants are associated with >30 human diseases. Furthermore, IF-containing inclusion bodies are characteristic features of several neurodegenerative, muscular, and other disorders. Acidic (type I) and basic keratins (type II) build obligatory type I and type II heteropolymers and are expressed in epithelial cells. Adult hepatocytes contain K8 and K18 as their only cytoplasmic IF pair, whereas cholangiocytes express K7 and K19 in addition. K8/K18-deficient animals exhibit a marked susceptibility to various toxic agents and Fas-induced apoptosis. In humans, K8/K18 variants predispose to development of end-stage liver disease and acute liver failure (ALF). K8/K18 variants also associate with development of liver fibrosis in patients with chronic hepatitis C. Mallory-Denk bodies (MDBs) are protein aggregates consisting of ubiquitinated K8/K18, chaperones and sequestosome1/p62 (p62) as their major constituents. MDBs are found in various liver diseases including alcoholic and non-alcoholic steatohepatitis and can be formed in mice by feeding hepatotoxic substances griseofulvin and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDBs also arise in cell culture after transfection with K8/K18, ubiquitin, and p62. Major factors that determine MDB formation in vivo are the type of stress (with oxidative stress as a major player), the extent of stress-induced protein misfolding and resulting chaperone, proteasome and autophagy overload, keratin 8 excess, transglutaminase activation with transamidation of keratin 8 and p62 upregulation

Differential Deployment of REST and CoREST Promotes Glial Subtype Specification and Oligodendrocyte Lineage Maturation

The repressor element-1 (RE1) silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) is a master transcriptional regulator that binds to numerous genomic RE1 sites where it acts as a molecular scaffold for dynamic recruitment of modulatory and epigenetic cofactors, including corepressor for element-1-silencing transcription factor (CoREST). CoREST also acts as a hub for various cofactors that play important roles in epigenetic remodeling and transcriptional regulation. While REST can recruit CoREST to its macromolecular complex, CoREST complexes also function at genomic sites independently of REST. REST and CoREST perform a broad array of context-specific functions, which include repression of neuronal differentiation genes in neural stem cells (NSCs) and other non-neuronal cells as well as promotion of neurogenesis. Despite their involvement in multiple aspects of neuronal development, REST and CoREST are not believed to have any direct modulatory roles in glial cell maturation.We challenged this view by performing the first study of REST and CoREST in NSC-mediated glial lineage specification and differentiation. Utilizing ChIP on chip (ChIP-chip) assays, we identified distinct but overlapping developmental stage-specific profiles for REST and CoREST target genes during astrocyte (AS) and oligodendrocyte (OL) lineage specification and OL lineage maturation and myelination, including many genes not previously implicated in glial cell biology or linked to REST and CoREST regulation. Amongst these factors are those implicated in macroglial (AS and OL) cell identity, maturation, and maintenance, such as members of key developmental signaling pathways and combinatorial transcription factor codes.Our results imply that REST and CoREST modulate not only neuronal but also glial lineage elaboration. These factors may therefore mediate critical developmental processes including the coupling of neurogenesis and gliogenesis and neuronal-glial interactions that underlie synaptic and neural network plasticity and homeostasis in health and in specific neurological disease states

Geschlechterstereotype und Geschlechterrollen

Zweitveröffentlichun

Ageing in general practice (AGP) trial: a cluster randomised trial to examine the effectiveness of peer education on GP diagnostic assessment and management of dementia

Extent: 9p.Background: Dementia is increasing in prevalence as the population ages. An earlier rather than later diagnosis allows persons with dementia and their families to plan ahead and access appropriate management. However, most diagnoses are made by general practitioners (GPs) later in the course of the disease and are associated with management that is poorly adherent to recommended guidelines. This trial examines the effectiveness of a peer led dementia educational intervention for GPs. Methods: The study is a cluster randomised trial, conducted across three states and five sites. All GPs will complete an audit of their consenting patients aged 75 years or more at three time points - baseline, 12 and 24 months. GPs allocated to the intervention group will receive two educational sessions from a peer GP or nurse, and will administer the GPCOG to consenting patients at baseline and 12 months. The first education session will provide information about dementia and the second will provide individualised feedback on audit results. GPs in the waitlist group will receive the RACGP Guidelines by post following the 12 month audit Outcomes: Primary outcomes are carer and consumer quality of life and depression. Secondary outcomes include: rates of GP identification of dementia compared to a more detailed gold standard assessment conducted in the patient’s home; GP identification of differential diagnoses including reversible causes of cognitive impairment; and GP referral to specialists, Alzheimers’ Australia and support services. A “case finding” and a “screening” group will be compared and the psychometrics of the GPCOG will be examined. Sample size: Approximately 2,000 subjects aged 75 years and over will be recruited through approximately 160 GPs, to yield approximately 200 subjects with dementia (reducing to 168 by 24 months). Discussion: The trial outlined in this paper has been peer reviewed and supported by the Australian National Health and Medical Research Council. At the time of submission of this paper 2,034 subjects have been recruited and the intervention delivered to 114 GPs.Constance D Pond, Henry Brodaty, Nigel P Stocks, Jane Gunn, John Marley, Peter Disler, Parker Magin, Nerida Paterson, Graeme Horton, Susan Goode, Bronwen Paine and Karen E Mat

Study protocol: the registrar clinical encounters in training (ReCEnT) study

Patient encounters are the core learning activity of Australian general practice (family practice) training. Exposure to patient demographics and presentations may vary from one general practice registrar (vocational trainee) to another. This can affect comprehensiveness of training. Currently, there is no mechanism to systematically capture the content of GP registrar consultations. The aim of the Registrar Clinical Encounters in Training (ReCEnT) study is to document longitudinally the nature and associations of consultation-based clinical and educational experiences of general practice registrars. This is an ongoing prospective multi-site cohort study of general practice registrars' consultations, entailing paper-based recording of consultation data. The study setting is general practices affiliated with three geographically-based Australian general practice regional training providers. Registrars record details of 60 consecutive consultations. Data collected includes registrar demographics, details of the consultation, patient demographics, reasons for encounter and problems managed. Problems managed are coded with the International Classification of Primary Care (second edition) classification system. Additionally, registrars record educational factors related to the encounter. The study will follow the clinical exposure of each registrar six-monthly over the 18 months to two years (full-time equivalent) of their general practice training program. The study will provide data on a range of factors (patient, registrar and consultation factors). This data will be used to inform a range of educational decisions as well as being used to answer educational research questions. We plan to use ReCEnT as a formative assessment tool for registrars and help identify and address educational needs. The study will facilitate program evaluation by the participating training providers and thus improve articulation of educational programs with practice experience. From the research point of view it will address an evidence gap - the in-practice clinical and educational experience of general practice trainees, determinants of these experiences, and the determinants of registrars' patterns of practice (for example, prescribing practice) over the course of their training