Arteriolar involvement in the microvascular lesions of diabetic retinopathy: Implications for pathogenesis

Diabetic retinopathy (DR) is the most widespread complication of diabetes mellitus and a major cause of blindness in the working population of developed countries. The clinicopathology of the diabetic retina has been extensively studied, although the relative contribution of the various biochemical and molecular sequelae of hyperglycemia remains ill defined. Many neural and microvascular abnormalities occur in the retina of short-term diabetic animals but it remains uncertain how closely these acute changes relate to chronic human disease. It is important to determine the relationship between alterations observed within the first weeks or months in short-term aminal models, and human disease, where clinically manifest retinopathy occurs only after durations of diabetes measured in years. This review is focused on the retinal microvasculature, although it should be appreciated that pathological changes in this system often occur in parallel with abnormalities in the neural parenchyma that may be derivative or even causal. Nevertheless, it is useful to reevaluate the microvascular lesions that are manifest in the retina during diabetes in humans and long-term animal models, since in addition to providing useful clues to the pathogenic basis of DR as a disease entity, it is in the deterrence of such changes that the efficacy of any novel treatment regimes will be measured. In particular, an emphasis will be placed on the relatively unappreciated role of arteriolar dysfunction in the clinical manifestations and pathology of this disease.

Digoxin toxicity in the aged. Characterising and avoiding the problem

Digoxin is one of the most frequently prescribed drugs, particularly in the elderly population where there is an increased prevalence of atrial fibrillation and cardiac failure. The drug has a narrow therapeutic range and has gained a reputation for producing adverse effects in older patients. The more frail elderly patients with coexistent disease, often taking other treatments, are more at risk from digoxin toxicity due to inappropriate dosing, noncompliance, or increased sensitivity to digoxin resulting from pharmacokinetic or pharmacodynamic interactions. Application of basic pharmacological principles may be helpful in anticipating these problems. Elderly patients more commonly receive digoxin than younger patients, which in part accounts for the higher rates of toxicity in this group. Numerous components contribute to the development of toxicity, and diagnosis of toxicity is difficult in this age group. The measurement of serum concentrations can contribute to the clinical diagnosis. A major problem is the accurate diagnosis of digoxin toxicity which may have numerous nonspecific clinical manifestations, many of which are related to coexisting disease in elderly patients. This diagnostic imprecision is well recognised but has been helped by the introduction of serum digoxin measurement. However, reliance on serum concentrations should not replace clinical judgement, since these do not always correlate with toxicity. The apparently decreasing incidence of toxicity over recent years probably reflects several factors: the improvement in digoxin formulations, awareness of digoxin pharmacology, utilisation of serum concentrations, and the realisation that digoxin withdrawal is a viable proposition in elderly patients. Greater knowledge about the causes and prevention of digoxin toxicity should further reduce the morbidity and mortality arising from digoxin overdose, especially in the elderly population.

Resemblance of psychotic symptoms and syndromes in affected sibling pairs from the Irish Study of High-Density Schizophrenia Families:evidence for possible etiologic heterogeneity

The authors sought to determine whether the clinical manifestations of schizophrenia and other psychotic disorders are correlated in affected sibling pairs.

The molecular basis of galactosemia - Past, present and future

Galactosemia, an inborn error of galactose metabolism, was first described in the 1900s by von Ruess. The subsequent 100years has seen considerable progress in understanding the underlying genetics and biochemistry of this condition. Initial studies concentrated on increasing the understanding of the clinical manifestations of the disease. However, Leloir's discovery of the pathway of galactose catabolism in the 1940s and 1950s enabled other scientists, notably Kalckar, to link the disease to a specific enzymatic step in the pathway. Kalckar's work established that defects in galactose 1-phosphate uridylyltransferase (GALT) were responsible for the majority of cases of galactosemia. However, over the next three decades it became clear that there were two other forms of galactosemia: type II resulting from deficiencies in galactokinase (GALK1) and type III where the affected enzyme is UDP-galactose 4'-epimerase (GALE). From the 1970s, molecular biology approaches were applied to galactosemia. The chromosomal locations and DNA sequences of the three genes were determined. These studies enabled modern biochemical studies. Structures of the proteins have been determined and biochemical studies have shown that enzymatic impairment often results from misfolding and consequent protein instability. Cellular and model organism studies have demonstrated that reduced GALT or GALE activity results in increased oxidative stress. Thus, after a century of progress, it is possible to conceive of improved therapies including drugs to manipulate the pathway to reduce potentially toxic intermediates, antioxidants to reduce the oxidative stress of cells or use of "pharmacological chaperones" to stabilise the affected proteins.

Alpha-1 antitrypsin deficiency: A conformational disease associated with lung and liver manifestations

Alpha-1 antitrypsin (A1AT) is a serine anti-protease produced chiefly by the liver. A1AT deficiency is a genetic disorder characterized by serum levels of less than 11 μmol/L and is associated with liver and lung manifestations. The liver disease, which occurs in up to 15% of A1AT-deficient individuals, is a result of toxic gain-of-function mutations in the A1AT gene, which cause the A1AT protein to fold aberrantly and accumulate in the endoplasmic reticulum of hepatocytes. The lung disease is associated with loss-of-function, specifically decreased anti-protease protection on the airway epithelial surface. The so-called 'Z' mutation in A1AT deficiency encodes a glutamic acid-to-lysine substitution at position 342 in A1AT and is the most common A1AT allele associated with disease. Here we review the current understanding of the molecular pathogenesis of A1AT deficiency and the best clinical management protocols. © Springer Science+Business Media B.V. 2008.

Clinical trials in cystic fibrosis

In patients with cystic fibrosis (CF), clinical trials are of paramount importance. Here, the current status of drug development in CF is discussed and future directions highlighted. Methods for pre-clinical testing of drugs with potential activity in CF patients including relevant animal models are described. Study design options for phase II and phase III studies involving CF patients are provided, including required patient numbers, safety issues and surrogate end point parameters for drugs, tested for different disease manifestations. Finally, regulatory issues for licensing new therapies for CF patients are discussed, including new directives of the European Union and the structure of a European clinical trial network for clinical studies involving CF patients is proposed.

Periodontal Manifestations of Chronic Atypical Neutrophilic Dermatosis With Lipodystrophy and Elevated Temperature (CANDLE) Syndrome in an 11 Year Old Patient

Introduction: Chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) is an auto inflammatory syndrome caused by an autosomal recessive gene mutation. This very rare syndrome has been reported in only 14 patients worldwide. A number of clinical signs have been reported including joint contractures, muscle atrophy, microcytic anaemia, and panniculitis-induced childhood lipodystrophy. Further symptoms include recurrent fevers, purpuric skin lesions, periorbital erythema and failure to thrive. This is the first reported case of periodontal manifestations associated with CANDLE syndrome. 
Case Presentation: An 11 year old boy was referred to Cork University Dental School and Hospital with evidence of severe periodontal destruction. The patient’s medical condition was managed in Great Ormond Street Children’s Hospital, London. The patient’s dental management included initial treatment to remove teeth of hopeless prognosis followed by prosthodontic rehabilitation using removable partial dentures. This was followed by further non-surgical periodontal treatment and maintenance. In the long term, the potential definitive restorative options, including dental implants, will be evaluated in discussion with the patient’s medical team.
Conclusion: Periodontitis as a manifestation of systemic disease is one of seven categories of periodontitis as defined by the American Academy of Periodontology 1999 classification system. A number of systemic diseases have been associated with advanced periodontal destruction including Diabetes Mellitus, Leukaemia and Papillon-Lefevre Syndrome. In the case described, treatment necessitated a multidisciplinary approach with input from medical and dental specialities for a young patient with severe periodontal destruction associated with CANDLE syndrome.