Bone quality: what is it and how is it measured?

Bone quality describes aspects of bone composition and structure that contribute to bone strength independently of bone mineral density. These include bone turnover, microarchitecture, mineralisation, microdamage and the composition of bone matrix and mineral. New techniques to assess these components of bone quality are being developed and should produce important insights into determinants of fracture risk in untreated and treated disease.     

Food allergy and constipation in childhood: how functional is it?

An increasing incidence of food allergy, especially to cow's milk proteins, is observed in children living in the industrialized regions of the world. In some cases responding to an eviction diet excluding offending foods, the 'functional' constipation can be caused by inflammation of the intestinal wall infiltrated by eosinophils. Understanding the complex mechanisms involved could help to improve the management of idiopathic functional constipation in children by addressing the aetiology instead of treating the symptoms.     

Clopidogrel: How good is it and how does it work?

Until recently, long-term antiplatelet therapy for the treatment and prevention of the complications of atherothrombotic disease was limited to aspirin. Although an incredibly costeffective therapy, in placebo-controlled clinical trials approximately 75% of patients at risk continue to experience thrombotic events despite chronic aspirin therapy. The availability of the thienopyridines, in particular clopidogrel, represents an important addition to the physician’s armamentarium. A number of clinical trials have confirmed the efficacy of the combination of clopidogrel and aspirin therapy compared with aspirin alone, with multiple other important largescale clinical trials currently ongoing. The exact mechanism of this benefit is still being elucidated but is clearly related to the inhibition of the many consequences of platelet activation—vascular inflammation, endothelial dysfunction, and localized angiogenesis/mitogenesis—and not just aggregation.     

Calcification in marine molluscs: how costly is it?

Although crucial to our understanding of skeletal evolution in marine invertebrates, the cost of calcification has remained elusive for a simple reason: CaCO3 is an inorganic material. Its cost thus derives solely from the metabolic expenses of accumulating, transporting, and precipitating CaCO3 and cannot normally be separated from other metabolic costs. Traditionally, calcification cost has been ignored and total shell cost has been assumed to derive solely from skeletal organic matrix. The cost estimated here was permitted by the substantial natural variation in shell thickness in two rocky-shore gastropods (Nucella lamellosa and Nucella lapillus). In both the field and laboratory, data from three separate experiments revealed that groups of snails producing extra shell material under a particular set of experimental conditions also consumed extra food. The cost of calcification was estimated by computing the extra energy assimilated per unit extra shell produced at a common rate of tissue growth and then subtracting the cost of the organic matrix. At 1-2 J/mg of CaCO3, the calcification cost reported here is roughly 5% of that for the predominantly proteinaceous organic fraction of molluscan shells on a per-gram basis. This may explain why calcareous microstructures high in organic content have become less common evolutionarily.     

Fatty liver: how frequent is it and why?

There is increasing evidence that fatty liver may be the most frequent liver disorder in Western countries. However, the epidemiology of fatty liver is still not fully understood and there is a clear need of better assessing and defining the potential role of the risk factors identified by clinical series in the general population. This article reviews the available data on the epidemiology of fatty liver and addresses some important questions that should be answered in much needed future research.     

What is healthcare-associated pneumonia and how is it managed?

PURPOSE OF REVIEW: Pneumonia developing before hospital admission in patients in close contact with the health system was recently termed 'healthcare-associated pneumonia' and proposed as a new category of respiratory infection. We focus on the recent literature concerning the epidemiology, causative organisms, antibiotic susceptibilities, and outcomes of and empirical antibiotic therapy for this condition. RECENT FINDINGS: The reported incidence of healthcare-associated pneumonia among patients requiring hospitalization for pneumonia ranges from 17% to 67%. Hospitalization within 90 days before pneumonia, attending a dialysis clinic and residing in a nursing home were the most common criteria for healthcare-associated pneumonia. Compared with patients with community-acquired pneumonia, those with healthcare-associated pneumonia are older, have greater co-morbidity, and are more likely to have aspiration pneumonia and pneumonia caused by antibiotic-resistant pathogens. Patients with healthcare-associated pneumonia also more frequently initially receive an inappropriate antibiotic therapy, have higher case fatality rates and have longer hospital stay. SUMMARY: Many patients hospitalized with pneumonia via the emergency department have healthcare-associated pneumonia. There are significant differences in the spectrum of causative organisms and antibiotic susceptibilities between healthcare-associated and community-acquired pneumonia. Physicians should differentiate patients with healthcare-associated pneumonia from those with community-acquired pneumonia to promote a targeted approach when selecting initial antibiotic therapy.     

Helicobacter pylori infection and diabetes: Is it a myth or fact?

Helicobacter pylori(H.pylori)is one of the most common human bacterial pathogens,and infection causes a wide array of gastric disorders,including simple gastritis,peptic ulcers and gastric malignancies.Gastrointestinal inflammation caused by H.pylori can influence the absorption of glucose and lipids,which are also abnormal in diabetes mellitus.Type 2 diabetes mellitus(T2DM),formerly known as non-insulin-dependent diabetes mellitus or adult-onset diabetes,is a metabolic disorder that is characterized by high levels of blood glucose resulting from insulin resistance and relative insulin deficiency.It is an emerging pandemic and is rapidly becoming a serious threat to public health.Emerging data now indicate a strong relationship between H.pylori infection and the incidence of T2DM.The mechanisms underlying the pathogenesis of diabetes are complex,involving insulin resistance,chronic inflammation,insulin secretion deficiency as a result of pancreasβ-cell dysfunction,glucotoxicity,and lipotoxicity.H.pylori infection is known to be involved in the pathogenesis of insulin resistance,and the growing awareness of its role in diabetes is important for the early detection of glucose dysregulation and prevention of T2DM in high-risk communities.This review probes the possible relationship between H.pylori and diabetes according to epidemiological surveys and discusses putative mechanisms underlying this correlation.     

Quality of drug prescribing in older patients: is there a problem and can we improve it?

Older patients are at high risk of suboptimal prescribing (overuse, underuse and misuse of drugs), which can lead to serious adverse drug reactions (ADR). About one in four patients admitted to hospital are prescribed at least one inappropriate medication and up to 20% of all inpatient deaths are attributed to potentially preventable ADR. Lists of drugs to avoid (unnecessary or where risks outweigh benefits) and drugs not to be omitted (strong indications if there are no contraindications) can assist in identifying suboptimal prescribing although, to date, no trials have established the ability of such screening, by itself, to improve prescribing quality. Remedial strategies proven to be effective in randomized trials include detailed appraisal of medication lists by multidisciplinary teams, which involve geriatricians and close liaison with specialist clinical pharmacists. A multifaceted quality improvement strategy is proposed that includes an aspirational target of no more than five different drugs be regularly prescribed to vulnerable older patients. Achieving this target involves prioritizing drug selection on the basis of strength of indication which may run counter to current disease-specific clinical guideline recommendations based on trials that have excluded most older patients. Such a strategy is worthy of further evaluation in a multicentre randomized trial.     

Inhaled corticosteroids and HPA axis suppression: how important is it and how should it be managed?

Inhaled corticosteroids (ICS) are established as a cornerstone of management for patients with bronchoconstrictive lung disease. However, systemic absorption may lead to suppression of the hypothalamic–pituitary–adrenal (HPA) axis in a significant minority of patients. This is more likely in ‘higher risk’ patients exposed to high cumulative ICS doses, and in those treated with frequent oral corticosteroids or drugs which inhibit cytochrome p450 3A4. Hypothalamic–pituitary–adrenal axis suppression is frequently unrecognized, such that some patients, notably children, only come to light when an adrenal crisis is precipitated by physical stress. To minimize this risk, ‘higher risk’ patients and those with previously identified suppressed cortisol responses to Synacthen testing should undergo an education programme to inform them about sick day rules. A review of ICS therapy should also be undertaken to ensure that the dose administered is the minimum required to control symptoms.