Methods in molecular biology
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The retinol carrier retinol-binding protein (RBP) forms in blood a complex with the thyroid hormone carrier transthyretin (TTR). The interactions of retinoid-RBP complexes, as well as of unliganded RBP, with TTR can be investigated by means of fluorescence anisotropy. RBP represents the prototypic lipocalin, in the internal cavity of which the retinol molecule is accommodated. ⋯ The fluorescence anisotropy technique is also suitable to study the interaction of TTR with apoRBP and RBP in complex with non-fluorescent retinoids. In the latter cases, the fluorescence signal is provided by a fluorescent probe covalently linked to TTR rather than by RBP-bound retinol. We report here on the preparation of recombinant human RBP and TTR, the covalent labeling of TTR with the fluorescent dansyl probe, and fluorescence anisotropy titrations for RBP and TTR.
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The heat/capsaicin sensitization and intradermal capsaicin injection models are safe and noninvasive paradigms to generate stable, long-lasting, and reproducible injury capable of producing an area of both primary and secondary hyperalgesia. Risk of skin injury is substantially reduced since lower levels of thermal and chemical irritation produce long-lasting cutaneous hyperalgesia. ⋯ Unlike the heat/capsaicin sensitization model, intradermal capsaicin results in a brief painful stimulus followed by a long lasting area of secondary hyperalgesia. The intradermal injection of capsaicin results in a transient, intense stinging sensation at the site of injection (e.g. heat allodynia) followed by a persistent area of secondary tactile allodynia.
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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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A wide variety of bioimaging techniques (e.g., ultrasound, computed X-ray tomography, magnetic resonance imaging (MRI), and positron emission tomography) are commonly employed for clinical diagnostics and scientific research. While all of these methods use a characteristic "energy-matter" interaction to provide specific details about biological processes, each modality differs from another in terms of spatial and temporal resolution, anatomical and molecular details, imaging depth, as well as the desirable material properties of contrast agents needed for augmented imaging. On many occasions, it is advantageous to apply multiple complimentary imaging modalities for faster and more accurate prognosis. ⋯ Multimodal contrast agents offer improvements in patient care, and at the same time can reduce costs and enhance safety by limiting the number of contrast agent administrations required for imaging purposes. Herein, we describe the synthesis and characterization of nanoparticulate-based multimodal contrast agent for noninvasive bioimaging using MRI, optical, and photoacoustic tomography (PAT)-imaging modalities. The synthesis of these agents is described using microemulsions, which enable facile integration of the desired diversity of contrast agents and material components into a single entity.
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This book is part of the Methods in Molecular Biology series, and provides a general overview of computational approaches used in proteome research. In this chapter, we give an overview of the scope of the book in terms of current proteomics experimental techniques and the reasons why computational approaches are needed. We then give a summary of each chapter, which together provide a picture of the state of the art in proteome bioinformatics research.