British medical bulletin
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Hereditary deafness has proved to be extremely heterogeneous genetically with more than 40 genes mapped or cloned for non-syndromic dominant deafness and 30 for autosomal recessive non-syndromic deafness. In spite of significant advances in the understanding of the molecular basis of hearing loss, identifying the precise genetic cause in an individual remains difficult. Consequently, it is important to exclude syndromic causes of deafness by clinical and special investigation and to use all available phenotypic clues for diagnosis. ⋯ Exceptions to this include DFNB2 (MYO7A), DFNB8/10 (TMPRSS3) and DFNB16 (STRC) where age of onset may sometimes be later on in childhood, DFNB4 (SLC26A4) where there may be dilated vestibular aqueducts and endolymphatic sacs, and DFNB9 (OTOF) where there may also be an associated auditory neuropathy. Unusual phenotypes in autosomal dominant forms of deafness, include low frequency hearing loss in DFNA1 (HDIA1) and DFNA6/14/38 (WFS1), mid-frequency hearing loss in DFNA8/12 (TECTA), DFNA13 (COL11A2) and vestibular symptoms and signs in DFNA9 (COCH) and sometimes in DFNA11 (MYO7A). Continued clinical evaluation of types and course of hearing loss and correlation with genotype is important for the intelligent application of molecular testing in the next few years.
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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.
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British medical bulletin · Jan 2002
ReviewUnder-rated neuro-otological symptoms: Hoffman and Brookler 1978 revisited.
In 1978, Hoffman and Brookler published an article in The Laryngoscope to challenge prevailing views on the lack of diagnostic power of certain symptoms often reported by patients to neuro-otologists. Some of these 'under-rated neuro-otological symptoms' include complaints of non-rotational dizziness, blurred and double vision, and the development of visual motion hypersensitivity in patients with balance disorders. In this review, I revisit these visual symptoms in the light of new findings from our laboratory. ⋯ Visual dependence denotes subjects who preferentially use vision, as opposed to vestibular or proprioceptive input, for spatial orientation and postural control. We do not know as yet what makes some vestibular patients become extremely visually dependent. However, we have provided evidence for Hoffman and Brookler's impression that visually triggered complaints should not be summarily dismissed, as they often point to an underlying vestibular disorder.
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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.