a significant proportion of the human population suffers from some form of skin disorder, whether it be from burn injury or inherited skin anomalies. the ideal treatment for skin disorders would be to regrow skin tissue from stem cells residing in the individual patient's skin. locating these adult stem cells and elucidating the molecules involved in orchestrating the production of new skin cells are important steps in devising more-efficient methods of skin production and wound healing via the ex vivo expansion of patient keratinocytes in culture. this review focuses on the structure of the skin, the identification of skin stem cells, and the role of notch, wnt and hedgehog signalling cascades in regulating the fate of epidermal stem cells.

Axenfeld–Rieger syndrome (ARS) is a rare autosomal dominant inherited disorder affecting the development of the eyes, teeth and abdomen. The syndrome is characterised by complete penetrance but variable expressivity. The ocular component of the ARS phenotype has acquired most clinical attention and has been dissected into a spectrum of developmental eye disorders, of which open-angle glaucoma represents the main challenge in terms of treatment. Mutations in several chromosomal loci have been implicated in ARS, including PITX2, FOXC1 and PAX6. Full-spectrum ARS is caused primarily by mutations in the PITX2 gene. The homeobox transcription factor PITX2 is produced as at least four different transcriptional and splicing isoforms, with different biological properties. Intriguingly, PITX2 is also involved in left–right polarity determination, although asymmetry defects are not a feature of ARS. In experimental animal models and in cell culture experiments using PITX2, abundant evidence indicates that a narrow window of expression level of this gene is vital for its correct function.

Wegener's granulomatosis (WG) is a complex autoimmune syndrome that is characterised by upper/lower respiratory necrotising granulomatosis, glomerulonephritis and small-vessel vasculitis. Since Wegener's 1936 description, considerable advances in recognition and treatment have changed this disease from a rapidly and uniformly fatal illness to a chronic disease characterised by remissions and relapses. The serendipitous discovery of anti-neutrophil cytoplasmic antibodies (ANCAs) as a marker associated with WG focused attention on the potential pathogenic role of these antibodies and has recently led to the development of novel animal models that might facilitate our understanding of the disease pathogenesis. Future animal models of this disease will have to account for the role of both ANCA-mediated pathology and granulomatous inflammation to enable us to understand the chronic and persistent features of WG in humans.

In an attempt to combat the pain and damage generated by rheumatoid arthritis (RA), new drugs are being developed to target molecular aspects of the disease process. Recently, a major development has been the use of biologicals (antibodies and soluble receptors) that neutralise the activity of tumour necrosis factor α (TNF-α) and interleukin 1 (IL-1), both of which are involved in disease progression. An increase in our understanding of cell and molecular biology has resulted in the identification and investigation of potential new targets, and also the refinement and improvement of current therapeutic modalities. This review describes therapies that are approved, in clinical trials or under pre-clinical investigation at the laboratory level, particularly focusing on cytokines, although other therapeutic targets of interest are mentioned.

Upper gastrointestinal (GI) tract malignancies, including carcinomas of the esophagus, the GI junction and the stomach, are among the most common cancers worldwide. Overall survival is poor because many patients present with locally advanced and often incurable disease. This review focuses on the pathogenesis of adenocarcinomas of the stomach. It summarises recent findings on genetic predisposition to gastric cancer, in particular in relation to germline mutations in the E-cadherin gene. It also describes the molecular basis of sporadic gastric cancer, including alterations in oncogenes, tumour suppressor genes and growth factors, and discusses how these findings might be used in the clinic for improved diagnosis and therapy.

Sorsby's fundus dystrophy (SFD) is a rare autosomal dominant disorder that results in degeneration of the macular region of the retina, with onset usually in the fourth to fifth decade of life. It leads to the rapid loss of central vision, often followed by further loss of peripheral vision. SFD shares several pathological features commonly found in the ‘wet’ or exudative form of age-related macular degeneration (AMD), the most common cause of blindness in the elderly in developed countries. These phenotypic similarities have led to SFD being proposed as an acceptable genetic model for AMD. Whereas AMD appears to have a complex aetiology, with both genetic and environmental factors playing a role, SFD has been shown to be a single-gene disorder, linked to mutations in exon 5 of the tissue inhibitor of metalloproteinases 3 (TIMP3) gene on chromosome 22q12-q13. This review confines itself to a discussion of the known biochemical properties of the wild-type and SFD TIMP3 proteins and attempts to relate these to the pathology encountered in SFD patients. We also discuss briefly how, despite the lack of inherited mutations in the structural gene, the TIMP3 protein might play a role in the onset and progression of AMD.

Multiple sclerosis (MS) is an autoimmune disease with an important genetic component. The strongest genetic association is with the major histocompatibility complex (MHC) region. Several MHC alleles predispose to the disease, the most prominent of which are certain alleles in the HLA-DR2 haplotype. Functional and structural studies have helped to explain the molecular basis of these associations. Although there is currently no curative treatment for MS, an increased understanding of the disease has aided the design of immunotherapies that act on the immune system more specifically than the longstanding drugs. Many of these therapies work at the antigen-specific level, disrupting the interaction between T-cell receptors and MHC molecules that leads to disease.

myocardial fibrosis is a common endpoint in a variety of cardiac pathologies. it results from excessive accumulation of collagen and other materials that together comprise the extracellular matrix (ecm). in the past decade, the peptide hormone relaxin has emerged as an important regulator of the ecm within several organs, including the heart, and has been suggested as a novel therapeutic agent for the treatment of fibrotic disorders. this review summarises research on the anti-fibrotic actions of relaxin, outlines the potential mechanisms by which relaxin regulates the ecm in cardiovascular tissues and examines the implications of this research for the management of heart disease. some of the contradictions in the literature are also addressed in order to clarify the role of relaxin as an anti-fibrotic factor in vivo.

Tumour hypoxia stems from impaired oxygen delivery as a result of a disorganised tumour vasculature and inadequate blood supply. Hypoxic tumours are highly resistant to chemotherapy and radiation therapy and correlate with a poor patient prognosis. Hypoxia is a powerful stimulus for the expression of genes involved in cell survival and angiogenesis. A key factor in this process is hypoxia-inducible factor (HIF), which regulates transcription of hypoxia-activated genes. Efforts are currently under way to develop targeted cancer therapeutics to hypoxia-activated pathways, and in particular to the transcription factor HIF.