British medical bulletin
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Current evidence suggests that the overall load of infectious agents, including respiratory viruses, encountered early in life is an important factor influencing maturation of the immune system from a type 2 bias at birth towards predominantly type 1 responses, thus avoiding atopic diseases. The 'hygiene hypothesis' proposes that the relatively sterile environment present in industrialised Western countries has contributed to the recent epidemic of asthma and atopy. Whether specific infections are of greater or lesser protective value is an important question if strategies are to be derived to mimic the beneficial effects of childhood infection whilst avoiding morbidity and potential mortality of the natural pathogens. ⋯ Viruses are detected in up to 85% of such episodes. Rhinovirus is common in all age groups; respiratory syncytial virus (RSV) is most important in infants and young children. Knowledge of the immunopathogenetic mechanisms of virus infection in the asthmatic airway will lead to the development of new treatments for virus-induced asthma.
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Radiotherapy has an established role in the treatment of rectal cancer. In primary resectable cancer, numerous randomised trials have shown that particularly pre-operative, and to some extent also postoperative, radiotherapy substantially reduces the risk of local failure. This is seen also with total mesorectal excision. ⋯ In non-resectable cancer, radiotherapy may cause down-staging, allow surgery, and may cure some patients. Whether radiochemotherapy is more efficient has yet to be firmly established. The role of pre-operative radio(chemo)therapy to permit more sphincter-preserving procedures with adequate long-term function is not defined.
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There is currently intense research activity aimed at the development of new delivery systems for vaccines. The goal is to identify optimal methods for presenting target antigens to the immune system in a manner that will elicit immune responses appropriate for protection against, or treatment of, a specific disease. ⋯ This article will review three categories of delivery systems: (i) adjuvants and formulations; (ii) antigen vectors, including live attenuated micro-organisms and synthetic vectors; and (iii) novel devices for vaccine administration. The review will be restricted to late stage developments in the field of human vaccination.
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Colorectal cancer is a important public health problem: there are nearly one million new cases of colorectal cancer diagnosed world-wide each year and half a million deaths. Recent reports show that, in the US, it was the most frequent form of cancer among persons aged 75 years and older. ⋯ While there are many questions to be resolved, it is apparent that many facets of colorectal cancer are becoming increasingly understood and prospects for prevention are becoming apparent. Achieving colorectal cancer control is the immediate challenge.
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Pneumocystis carinii is an atypical fungus that causes pneumonia in immunocompromised individuals. P. carinii comprises a heterogeneous group of organisms that have been isolated from a wide range of mammalian host species. ⋯ It addresses the use of DNA amplification for the detection and diagnosis of P. carinii pneumonia. Studies investigating the reservoir of infectious P. carinii organisms, the routes of transmission of the infection, and the emergence of drug resistant strains of P. carinii are also discussed.