How insects survive the cold: molecular mechanisms - a review

Insects vary considerably in their ability to survive low temperatures. The tractability of these organisms to experimentation has lead to considerable physiology-based work investigating both the variability between species and the actual mechanisms themselves. This has highlighted a range of strategies including freeze tolerance, freeze avoidance, protective dehydration and rapid cold hardening, which are often associated with the production of specific chemicals such as antifreezes and polyol cryoprotectants. But we are still far from identifying the critical elements behind over-wintering success and how some species can regularly survive temperatures below -20°C. Molecular biology is the most recent tool to be added to the insect physiologist’s armoury. With the public availability of the genome sequence of model insects such as Drosophila and the production of custom-made molecular resources, such as EST libraries and microarrays, we are now in a position to start dissecting the molecular mechanisms behind some of these well-characterised physiological responses. This review aims to provide a state of the art snapshot of the molecular work currently being conducted into insect cold tolerance and the very interesting preliminary results from such studies, which provide great promise for the future

Canadian Guidelines for the Management of Acute Exacerbations of Chronic Bronchitis

Acute exacerbations of chronic bronchitis (AECB) account for over 1.5 million physician visits annually in Canada and are a cause of significant morbidity and mortality. This document represents a joint effort between respirologists, microbiologists, infectious disease specialists and family physicians to update the Canadian AECB guidelines published in 1994. Treatment recommendations are graded on the strength of evidence in the published literature where possible. The role for oral corticosteroid therapy in preventing treatment failures, speeding up recovery and delaying the time to next exacerbation is discussed. Risk factors for treatment failure were used to stratify patients into risk groups to help guide antibiotic treatment recommendations. The importance of emerging antimicrobial resistance to current antibiotics is reviewed and strategies to prevent future AECB episodes are suggested.Peer Reviewe

Canadian Guidelines for the Management of Acute Exacerbations of Chronic Bronchitis

Acute exacerbations of chronic bronchitis (AECB) account for over 1.5 million physician visits annually in Canada and are a cause of significant morbidity and mortality. This document represents a joint effort between respirologists, microbiologists, infectious disease specialists and family physicians to update the Canadian AECB guidelines published in 1994. Treatment recommendations are graded on the strength of evidence in the published literature where possible. The role for oral corticosteroid therapy in preventing treatment failures, speeding up recovery and delaying the time to next exacerbation is discussed. Risk factors for treatment failure were used to stratify patients into risk groups to help guide antibiotic treatment recommendations. The importance of emerging antimicrobial resistance to current antibiotics is reviewed and strategies to prevent future AECB episodes are suggested