Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1
    Digitale Medien
    Digitale Medien
    The Effect of Radiofrequency Catheter Ablation on Myocardial Creatine Kinase Activity (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiovascular electrophysiology 6 (1995), S. 0 
    Details
    ISSN: 1540-8167
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: RF Ablation and Creatine Kinase. Introduction: The primary mechanism of myocardial injury during radiofrequency (RF) catheter ablation in the heart is presumed to be thermal. Creatine Kinase has been measured in serum to assess the volume of myocardial injury after ablation. However, its thermal inactivation by RF ablation could lead to underestimation of the true volume of injury. Methods and Results: Serial RF lesions were created in 10 canine left ventricles in vivo, and serial serum Creatine Kinase activities were measured and compared to lesion volume. To assess the stability of myocardial Creatine Kinase during RF catheter ablation, 29 RF ablations were made on the epicardial surface of porcine left ventricle in vivo and a 2-mm core biopsy was rapidly removed. The cores were rapidly frozen, sectioned longitudinally in 1-mm slices, and homogenized in 0.3 M Tris buffer solution containing EDTA and dithiothreitol for subsequent analysis of Creatine Kinase activity. An additional 19 tissue cores from RF lesions were stained and used to determine mean lesion depth. Normal tissue biopsies were exposed to 60 seconds of hyperthermia (37° to 85°C, n = 190), or high-density RF current at 50X (0 to 100 mA/mm2, n = 50), and tissue Creatine Kinase activity was measured. There was no evidence of Creatine Kinase washout within the first 2 hours, and peak values were measured 5 to 7 hours postablation. Tissue Creatine Kinase activity in the first mm depth of RF lesions averaged 10% of control values and increased over the first 5 mm of lesion depth. The mean Creatine Kinase activity within the hemisphere of ablated myocardium was calculated to be 31% of control. Creatine Kinase activity declined significantly at temperatures above 65°C, but no difference in tissue Creatine Kinase activity was observed among differing levels of RF current exposure in the absence of significant heating. Conclusions: Creatine Kinase activity in myocardial tissue is significantly diminished within the RF lesion. Creatine Kinase activity is not stable at temperatures above 65°C, which are routinely achieved within the central zone of RF ablation, and is unaffected by RF current in the absence of hyperthermia. Measurements of serum Creatine Kinase activity after RF catheter ablation may significantly underestimate the volume of myocardial injury.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1540-8167.1995.tb00760.x
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Ultrastructural localization of the 9-kilodalton vitamin d-dependent calcium-binding protein in the murine intraplacental yolk sac (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 222 (1988), S. 252-259 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The calcium-binding protein (CaBP) calbindin has been implicated in the molecular mechanism of placental calcium transfer. Previous light microscopic studies have identified CaBP in visceral (but not parietal) endodermal cells of the yolk sac with the most intense immunocytochemical signal observed in the intraplacental yolk sac. In the present studies, electron microscopy was used to study the localization of CaBP in placenta.Placentas of 17-day pregnant mice were fixed by perfusion in 0.5% gluteraldehyde, embedded in low-temperature Lowicryl K4M, and examined in thin section for specific labeling with a polyclonal antiserum. Antibody to CaBP was localized by using protein A-gold particles which were quantified for subcellular compartmentation by using a Videoplan computer system. A high signal for CaBP was found in the visceral endodermal cells of the intraplacental yolk sac. In these cells, gold particles indicating the location of CaBP were observed over (1) the cytoplasmic matrix where the average number of gold particles per μm2 was 33; (2) the microvilli (17/μm2); (3) the mitochondria (17/μm2); and (4) the nucleus (43/μm2). Sections from antigen-absorbed controls, by contrast, showed few gold particles: cytosol, 2/μm2; microvilli, 5/μm2; mitochondria, 5/μm2; and nucleus, 4/μm2. Electron-lucent profiles of the Golgi and endoplasmic reticulum contained no particles in the controls and a low particle count (4/μm2) in the stained sections. Parietal endodermal cells of the intraplacental yolk sac showed a relatively low signal for CaBP compared with the visceral endodermal cells (5 particles/μm2 vs. 39). Only low numbers of gold particles were observed in trophoblasts (6/μm2), lymphocytes (5/μm2), and erythrocytes (5/μm2). These findings indicate that 9 kd CaBP is located predominantly in cytoplasmic matrix, nucleus, and mitochondria within the visceral endodermal cells of the intraplacental yolk sac.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092220306
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Immunochemical localization of vitamin D-dependent calcium-binding protein in mouse placenta and yolk sac (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 213 (1985), S. 514-517 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A 10,000-dalton calcium-binding protein (10-kd CaBP) has been described in the placentae and yolk sacs of rats and mice. This protein is similar or identical to vitamin D-dependent intestinal CaBP and these proteins have been implicated in the molecular mechanisms of intestinal calcium absorption and transplacental calcium transport. Using an antiserum to the purified 10-kd rat intestinal CaBP, the localization of CaBP in the 16-17-day mouse yolk sac and placenta was studied immunocytochemically with peroxidase-antiperoxidase labelling and quantified by radial immunodifussion. A high concentration of immunolabelling was observed in the endodermal cells of the intraplacental yolk sac lining the sinuses of Duval. The columnar endodermal cells lining one side of the endodermal sinuses adjacent to fetal vessels contained most of the immunoreactive label. Quantitation by radial immunodiffusion demonstrated a 5.5-fold higher concentration of CaBP in the portion of the placenta containing most of the intraplacental yolk sac than in the maternal half of the placenta. This demonstration of a 10-kd CaBP within the intraplacental yolk sac suggests this protein functions to facilitate placental calcium transport and is the first study which directly supports the hypothesis of a functional role for the sinuses of Duval in calcium transport.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092130406
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...