Methods in molecular biology
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In the last decade, radiological neuroimaging techniques have enhanced the study of mechanisms involved in the development and maintenance of neuropathic pain. Recent findings suggest that neuropathic pain in certain pain syndromes (e.g., complex regional pain syndrome/reflex sympathic dystrophy, phantom-limb pain) is associated with a functional reorganization and hyperexitability of the somatosensory and motor cortex. Studies showing that the reversal of cortical reorganization in patients with spontaneous or provoked pain is accompanied by pain relief stimulated the search for novel alternatives how to modulate the cortical excitability as a strategy to relieve pain. ⋯ Both techniques (TMS and tDCS) have been clinically investigated in healthy volunteers as well as in patients with various clinical pathologies and variety of pain syndromes. Although there is less evidence on tDCS as compared with TMS, the findings on tDCS in patients with pain are promising, showing an analgesic effect of tDCS, and observations up to date justify the use of tDCS for the treatment of pain in selected patient populations. tDCS has been shown to be very safe if utilized within the current protocols. In addition, tDCS has been proven to be easy to apply, portable and not expensive, which further enhances great clinical potential of this technique.
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Catechol-O-methyltransferase (COMT) is an enzyme that plays a key role in the modulation of catechol-dependent functions such as cognition, cardiovascular function, and pain processing. Recently, our group demonstrated that three common haplotypes of the human COMT gene, divergent in two synonymous and one nonsynonymous position, are associated with experimental pain sensitivity and onset of temporomandibular joint disorder. In order to determine the functional mechanisms whereby these haplotypes contribute to pain processing, a series of in vitro experiments were performed. ⋯ Site-directed mutagenesis that eliminated the stable structure restored the amount of translated protein. These data provide the first demonstration that combinations of commonly observed alleles in the coding region of the human COMT gene can significantly affect the secondary structure of corresponding mRNA transcripts, which in turn leads to dramatic alterations in the translation efficiency of enzyme crucial for a variety of essential functions. The protocols applied to the study of these molecular genetic mechanisms are detailed herein.
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The UV-B pain model utilizes ultraviolet light to induce a small area of inflammation allowing assessment of mechanical and thermal thresholds. Pharmacologic testing has mainly focused on reduction of primary hyperalgesia, although the effect of analgesics on secondary hyperalgesia has also been investigated. The model requires an instrument to precisely generate controlled UV-B tissue hyperalgesia. ⋯ Tissue is then assessed for inflammation using color Doppler imaging or flare measurements. Heat pain thresholds and pain tolerance are often evaluated using a commercially available thermal sensory testing device. Analgesics can be administered to determine the influence on these clinical endpoints.
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Limited understanding of the cell biology of the breast and breast cancer hampers our ability to develop new therapeutic approaches. Mouse models of mammary gland development and tumourigenesis are key to developing new insights into the biology of both the normal and diseased tissues. Recent advances have enabled the isolation, molecular characterisation and functional analysis of mouse mammary epithelial cell subpopulations from the normal gland, including subpopulations enriched for stem cell behaviour. Application of these techniques both to the normal mammary gland and to tumour models will promote a better understanding of the nature of the different epithelial cell types in the mammary gland, the origins of mammary tumours and the role of tumour stem cells.
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Although a number of animal models such as endotoxic shock and bacteremia have been used to study the pathogenesis of sepsis, cecal ligation and puncture (CLP) represents a peritonitis model with clinical features of polymicrobial infection comparable with those of peritonitis in humans. The CLP consists in the surgical perforation of the legated cecum of mice that results in immediate and constant drainage of cecal bacteria into the peritoneal cavity. The severity of the diseases depends on the diameter of the needle used for the perforation as well as on the number of cecal punctures. The CLP model of sepsis in mice is the most commonly used for studying the process of septic peritonitis and can be used as a preclinical model to test the efficacy of pharmacological agents for the treatment of sepsis.