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Nano-Sized CT Contrast Agents *
Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Nohyun Lee, Seung Hong Choi, Taeghwan Hyeon
Nanoemulsions of iodinated triglyceride (1,3-Bis-[7-(3-amino-2,4,6-triiodophenyl)-heptanoyl]-2-oleoyl glycerol (DHOG), also known as Fenestra LC) have also been developed as efficient CT contrast agents [29]. Since triglyceride is a main component of chylomicrons that transport exogenous lipids to the liver, Fenestra LC is taken up by the hepatocytes via apolipoproteinE (apoE) receptor, and then the internalized nanoemulsions are metabolized and excreted through the bile. Thus, Fenestra LC has been used to study liver metabolism or to detect liver tumors. The circulation times of nanoemulsions containing DHOG can be increased by incorporating PEG because PEG can interfere with the recognition of hepatocytes by apoE receptors or phagocytes [30]. The long-circulating nanoemulsions Fenestra VC is now commercialized for use as a vascular contrast agent. Hydrophobic DHOG can also be loaded in the low-density lipoprotein (LDL) nanoparticles [31]. Since LDL cell surface receptor (LDLR) is overexpressed in several tumors, these nanoparticles have potential for targeted tumor imaging.
Pathophysiologic Mechanisms of Acute Renal Failure
Published in Robin S. Goldstein, Mechanisms of Injury in Renal Disease and Toxicity, 2020
Decreases in glomerular permeability may be more important contributors to filtration failure in toxic acute renal failure. For example, uranyl nitrate induced a dose-dependent decrease in K1 2 h after administration. These functional changes corresponded to a decrease in the size and density of endothelial fenestrae by morphologic examination.71 The glomerular capillary ultrafiltration coefficient is also diminished following gentamicin administration to rats,72 although endothelial pore size and density may not be decreased.73 However, in most instances, additional defects such as tubular backleak of glomerular filtrate also exist and may contribute to glomerular filtration failure. On the other hand, the available filtration surface is dependent on the state of mesangial cell tone and, because angiotensin II and vasopressin can cause mesangial cell contraction, elevation of these substances in acute renal failure can contribute to impaired renal function.74 In experimental gentamicin toxicity in the rat, antagonism of angiotensin II was found to improve an abnormally low K1 value.75
Biology of Joints
Published in Verna Wright, Eric L. Radin, Mechanics of Human Joints, 2020
Articular tissues receive a generous blood supply through an anastomosing network of vessels that Hunter first recognized and called the circulus articularis vasculosus. With the exception of articular cartilage, which is avascular, all joint tissues (including juxtaarticular bone) receive blood vessels from this source (30). That portion of the blood supply that is destined for the synovium is distributed through an extensive vascular bed. At rest, flow through these vessels is comparable to that of other articular soft tissues. With modest exercise, however, synovial blood flow rises as much as sevenfold (31). Fenestrations provide the most conspicuous feature of the synovial microvascular bed. These “windows” are usually found on the adluminal side of the vessel. As in other sites where they are found, such as the glomeruli of the kidney, fenestrae are thought to retain proteins while providing free exchange of water and other small solutes between plasma and surrounding interstitial fluid (32).
Otosclerosis and stapedotomy: hearing improvement, complications, and analysis of potential prognostic factors in a series of 93 cases
Published in Acta Oto-Laryngologica, 2023
Charlotte Wedel, Niels H. Holm, Frank Mirz, Therese Ovesen
All surgeries were performed under general anaesthesia by one of three ear surgeons trained in the stapedotomy procedure. The small fenestra technique was used, involving Rosen’s incision and elevation of a tympanomeatal flap. The chorda tympany was identified, and a proper view of the facial canal and the stapes footplate was obtained. A 0.5 mm fenestration of the footplate was created using a Lumenis CO2-laser. In two cases, microdrill (Medtronic Xomed Skeeter Drill Ultra-Lite) was used in conjunction with the laser during the stapedotomy. The appropriately sized prosthesis was selected and fitted into the fenestration. The incudo-stapedial joint was separated, and the stapes tendon and the posterior crus of the stapes were severed using a Lumenis CO2 laser. The anterior crus was then divided. The prostheses used were either Fisch Piston, Kurz Titanium Matrix or Kurz Angular Piston (in the case of revision surgery).
Do otosclerosis and stapedotomy affect semicircular canal functions? Preliminary results of video head impulse test
Published in Acta Oto-Laryngologica, 2021
Bülent Satar, Ceren Karaçaylı, Volkan Kenan Çoban, Songül Özdemir
This retrospective study included 11 otosclerosis patients who had undergone small fenestra stapedotomy (seven females, four males; age range 34–55, mean age 43.81 ± 7.71), and 30 healthy subjects with no auditory and balance problems (five females; 25 males; age range 24–69, mean age 38.57 ± 9.99). The procedures were performed under the Declaration of Helsinki and approved by the Ethics Committee of the University (19/69). Middle ear exploration followed by stapes surgery was warranted when air-bone gap exceeded 25 dB. Stapes surgery had been a standard small fenestra stapedotomy followed by insertion of a piston prosthesis of 5-mm long and 0.6 mm diameter. Stapes surgeries had been performed by the same surgeon. Postoperative period had been uneventful. One patient had been operated bilaterally with a year-interval. Twenty-two ears of 11 patients with otosclerosis were divided into two groups based on whether the ear had been operated or not operated (operated ears versus unoperated contra-lateral ear versus control ears) in order to investigate effects of otosclerosis and stapedotomy on vHIT. Twelve of the ears were operated, and 10 of the ears were not operated.
The impact of shrunken pore syndrome in patient with rheumatic diseases on bone mineral metabolism
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2021
Ichiro Yoshii, Susumu Nishiyama
Normal kidney-filtering capacity relies on the function and structural integrity of the glomerular filtration barrier. The glomerular filtration barrier between the vasculature and the urinary space consists of three layers: the fenestrated endothelial cells, the podocytes, and the intervening glomerular basement membrane [5]. Normally, a remarkably small fraction of albumin and other large plasma proteins pass across the glomerular capillary wall despite the massive filtration of water and small solutes [6]. Glomerular endothelial cell fenestrae are essential for the clearance of low-molecular-weight products from circulation by filtration [7]. However, once a reduction in the pore diameter of the fenestra in the endothelial cells occurs, GFR varies in accordance with the molecular weight of the polypeptides [8]. The molecular weight of CysC is 13,000 dalton (Da), whereas that of Cr is 133 Da. Thus, the estimated GFR based on CysC (eGFRcysC) would change while the eGFR based on Cr (eGFRCr) would not change. Cr should penetrate the filtration system; however, some quantity of CysC will not penetrate [1–4,9]. Serum CysC would rise and then eGFRcysC would increase, and therefore, a split between eGFRcysC and eGFRCr should occur. This is indicated to be pathogenesis of SPS. Grubbs et al. defined SPS as eGFRcysC/eGFRCr <0.6 [4].