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Techniques for Chest Radiography, Fluoroscopy, Tomography (including CT and MR) and Ultrasound
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
Digitisation of radiographic images is being increasingly employed with CT, MR, nuclear medicine and ultrasound. Both digital fluoroscopy and radiography are employed with digital vascular imaging (DVI), which also allows subtraction. Digital recording and displays are also now becoming available for conventional radiographic procedures, including barium studies and chest radiography. Some companies are producing systems for storing all radiographic images in a central storage and retrieval system. In digitisation, the image is converted into a matrix of small pixels, rather like ancient Roman mosaic patterns. These can be processed using a computer to alter the density, contrast or polarity. Picture clarity depends on the number of pixels (or picture elements) within it, and the resolution of the system. The density of each pixel in the display can be represented according to the number of 'bits' (commonly eight, giving about 256 different levels).
Visceral and renal artery interventions
Published in Peter A. Schneider, Endovascular Skills: Guidewire and Catheter Skills for Endovascular Surgery, 2019
There are challenges in stent placement in the visceral segment. Fluoroscopic image clarity is diminished because of the depth of the location and the thickness of the tissue that must be penetrated. There is a continuous movement of vascular structures. Bowel gas often obscures the target site. This is an area where heavy calcifications may occur, especially along the anterior wall at the origins of the visceral arteries and sometimes along the posterior wall, where it is desirable to avoid embolization by disrupting this material. If there is a severe angle of exit from the aorta, and especially if it is a SMA or there is significant infrarenal pathology, then a transbrachial approach is more desirable. It is usually best to place the tip of the delivery sheath either inside the origin of the artery or very close to it to support treatment.
Skeletal Muscle Microcirculation
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
Michael A. Hill, Gerald A. Meininger
As it is beyond the scope of this brief chapter to describe the procedures for the many available in vivo skeletal muscle preparations, the rat exteriorized cremaster muscle is presented as a typical example. The method described is a variation on that described in 1973 by Baez.81 This tissue provides a relatively thin sheet of skeletal muscle (200–300 µm), which is easily transilluminated (especially in younger animals; <200 g body weight) to give reasonable optical clarity. The reader is referred to the references in Table 1 for specific details of other preparations.
Virtual screening and zebrafish models in tandem, for drug discovery and development
Published in Expert Opinion on Drug Discovery, 2023
David Hernández-Silva, Francisca Alcaraz-Pérez, Horacio Pérez-Sánchez, Maria Luisa Cayuela
Green fluorescent protein (GFP) transgenic reporter. Zebrafish is a viable whole animal model for monitoring cell or biological processes [91]. This is supported by the optical clarity of the embryo in combination with advancements in imaging technologies. Seventeen flavonoids as inhibitors or of angiogenesis were identified in almost 36,043 compounds from the Traditional Chinese Medicine (TCM) database [92]. They were identified after computational screening against the crystal structure of human COX-2, human mPGES-1, and the 3D structure of CYP4A11 (Arachidonic acid metabolic enzymes), which all play an important role in glioma angiogenesis. Using a transgenic zebrafish line that expresses GFP in endothelial cells (Tg(fli1a:EGFP), isoliquiritigenin exhibited the most potent antiangiogenic activities. Therefore, in silico and zebrafish screening working in tandem is an efficient strategy for screening multiple-target inhibitors to block a biological process.
Use of Decellularized SMILE (Small-Incision Lenticule Extraction) Lenticules for Engineering the Corneal Endothelial Layer: A Proof-of-Concept
Published in Current Eye Research, 2023
Swatilekha Hazra, Jacquelyn Akepogu, Supriya Krishna, SriRavali Pulipaka, Bhupesh Bagga, Charanya Ramachandran
For tissue engineering, the biological source must be decellularized because the presence of residual cellular material can trigger the immune system to reject the transplantation or can affect the remodeling following transplantation.19,20 While ensuring sufficient decellularization, it is also important to retain much of the native extracellular matrix (ECM), which is known to regulate cell mitogenesis, differentiation and can induce host tissue remodeling.21–23 In the case of corneal transplantation, the tissue transparency must also be unaffected following decellularization. Several chemical (e.g. detergents), enzymatic (e.g. collagenase, trypsin), and physical methods (e.g. compression, freeze-thawing) have been used to decellularize human and animal corneal tissues.18,24–35 The efficacy of these techniques at removing cellular components varies with tissue thickness but the most common drawbacks reported are the stripping of ECM proteins, compromised optical clarity, and a loss in the tensile strength of the tissue. Further, the residual presence of any of the chemicals used for decellularization can evoke an adverse immune response after transplantation thus requiring extensive washing over several hours or days.
Occupational identity in occupational therapy: A concept analysis
Published in Scandinavian Journal of Occupational Therapy, 2022
Sandra Ocasio Hansson, Anita Björklund Carlstedt, Anne-Le Morville
Despite substantial investigation, OI is still in an incipient stage with vital aspects in need of further development and reformulation [4,12]. OI has been utilized in OT literature without explanation and when defined, variations in its characterization exist [12,20–22], implying disagreement regarding what OI means and just what it entails. Inconsistencies contribute to ambiguity regarding OI’s identification and application. Clarity of use and meaning is critical to knowing what phenomena one is influencing or investigating [23]. Moreover, there has been critique of OI being too oriented on the individual without adequately reflecting surrounding socio-cultural perspectives [4,24]. Uncertainties concerning OI’s defining aspects indicate a need for conceptual clarification and refinement. This is particularly true given the pivotal link between occupation and identity over one’s lifetime and its consequent relevance within OT.