(n.) A rare metallic element of the platinum group, found native as an alloy in platinum ore, and in iridosmine. It is a hard, infusible, bluish or grayish white metal, and the heaviest substance known. Its tetroxide is used in histological experiments to stain tissues. Symbol Os. Atomic weight 191.1. Specific gravity 22.477.
Example Sentences:
(1) Effects of fixation with glutaraldehyde (GA), glutaraldehyde-osmium tetroxide (GA-OsO(4)), and osmium tetroxide (OsO(4)) on ion and ATP content, cell volume, vital dye staining, and stability to mechanical and thermal stress were studied in Ehrlich ascites tumor cells (EATC).
(2) The modified osmium-urea method gave better results and was easier to perform than the collagenase method.
(3) Additionally, by ultrasonic vibration of tissues that had been subjected to prolonged osmium fixation, the epithelium was removed and such microdissected membranes similarly were examined.
(4) The renal tissue was fixed with a mixture of buffered picric acid-paraformaldehyde-glutaraldehyde and immunostained with the peroxidase-antiperoxidase method for the electron microscope with the following steps: antikallikrein antiserum, anti-IgG serum, peroxidase-antiperoxidase complex, 3-3' diaminobenzidine-H2O2, and post-staining with osmium tetroxide.
(5) It was also found that tritium release also occurred, although to a lesser extent, when tissues were fixed in glutaraldehyde or osmium tetroxide using collidine as a buffer, and this release was not significant when collidine was applied to previously fixed tissues.
(6) In accordance with the physiological experiments, electronopaque pyroantimonate precipitate containing calcium was found in the lumina of caveolae, but not in any intracellular structures close to the plasma membrane, when the relaxed fibers were fixed in a 1% osmium tetroxide solution containing 2% potassium pyroantimonate.
(7) The addition of oxalate to a suspension of rabbit peritoneal neutrophils before fixation with glutaraldehyde and postfixation with osmium tetroxide-antimonate greatly enhanced the amount of calcium antimonate precipitate subsequently detectable with the electron microscope.
(8) Ultrastructurally, hemolytic concentrations of tributyltin can be visualized in the electron microscope by osmium staining during fixation as electron-dense spheres penetrating the lipid bilayer of the erythrocyte plasma membrane.
(9) Their visualisation appeared to be enhanced when ruthenium red was incorporated n the glutaraldehyde-osmium fixative but only when sections were stained with heavy metal salts, indicating that the fimbriae and capsule were not predominantly polysaccharide in nature.
(10) Intravascular fat in tissue postfixed in osmium tetroxide, embedded in epoxy or paraffin, and stained with toluidine blue, hematoxylin, or Oil Red O is more easily visualized than in frozen tissue that is stained with Oil Red O.
(11) Mitotic cells were selectively removed from the cultures with 0.2 per cent trypsin and fixed in either osmium tetroxide or glutaraldehyde followed by osmium tetroxide.
(12) Human cochleae were fixed in glutaraldehyde, without the use of osmium.
(13) No reaction was observed in general with osmium-amine, with the exception of a few cases.
(14) Glutaraldehyde-fixed testes were stained "en bloc" with the Ur-Pb-Cu technique of Thiéry and Rambourg ('76) or post-fixed and stained with the osmium tetroxide-potassium ferrocyanide method of Karnovsky ('71).
(15) Insertion of 28 alternating AT residues at the EcoRV site of pBR322 generates an site hypersensitive to osmium tetroxide modification, that does not serve as a transcription start site.
(16) The osmium tetroxide fixation technique was used for determination of cell size and number.
(17) It uses carbohydrazide as an osmium bridging agent and both osmium tetroxide and uranyl acetate as electron staining agents.
(18) Parallel microsamples were fixed with osmium tetroxide and with glutaraldehyde followed by osmium tetroxide as previously used in this laboratory for the preservation of energy-linked mitochondrial configurations.
(19) A combination of 2% osmium tetroxide-2% uranyl acetate or 2% gallic acid alone resulted in optimum fixation as ascertained by least extraction of radiolabels.
(20) In those instances, the osmium-amine reacted not only in the outer surface of the mesentery, but also penetrated with no visible reaction all the way to the connective tissue where it was detected in the elastic layer.
Ostium
Definition:
(n.) An opening; a passage.
Example Sentences:
(1) A block of tissue bounded by the ostium of the coronary sinus, the pars membranacea, the septal leaflet of the tricuspid valve and the atrial and ventricular septa is removed.
(2) Depending on local anatomical properties duplex scanning failed to make a decision about the state of the ostium of the vertebral artery in 24% of the cases.
(3) In the hearts of normal weight (195 to 300 gm) the Thebesian valve covered the ostium of the coronary sinus an average of 41%, with complete coverage in 20%.
(4) Operative intervention showed a dysplastic bicuspid aortic valve with a membrane that covered the left coronary ostium.
(5) The intervention was undertaken for restenosis of the left venous ostium in 255 and iatrogenic mitral insufficiency in 20 patients.
(6) The left coronary ostium was reimplanted with Carrel patch method and the right coronary artery was bypassed with the saphenous vein graft.
(7) Technical problems encountered with the use of these catheters included instability of the right Judkin's catheter in the right coronary ostium owing to high torquability, streaming of contrast during left coronary injections, and difficulty entering the left ventricle with a pig-tail catheter.
(8) The proximal topography of the left common carotid artery ostium is a useful sign in the diagnosis of this kind of abnormality.
(9) Four cases of atrial septal defect, "ostium secundum", associated with pulmonary hypertension and congestive heart failure in children under the age of two years are reported.
(10) On the basis of this study the area of the right coronary ostium appears to be a bottleneck with regard to an adequate blood supply to a hypertrophic myocardium.
(11) Frequently a contrast medium reflux occurs out of the coronary ostium into the aorta.
(12) The data show that coronary sinus blood flow changes from 23 to 68 ml X min-1 per cm catheter movement, the nearer the ostium the greater the change.
(13) Another facilitating factor which is discussed is that blowing the nose may catch tenacious mucus which has partly passed through the ostium by the ciliary activity in the sinus.
(14) There were 69 SBs: 43 with severe ostium stenosis (type A); 6 with severe non ostial stenosis (type B); and 20 with no or slight nonostial stenosis (type C).
(15) The following abnormalities were found at operation: a disrupted right coronary cusp, a torn chorda of the anterior mitral leaflet, a dilated tricuspid annulus, and an intimal tear on the aortic root near the right coronary ostium that had developed into an aneurysm of the sinus of Valsalva.
(16) Furthermore, the method is useful to evaluate the optimal therapy to restore ventilation in the case of an obstructed ostium demonstrated before and after surgical opening in the inferior meatus.
(17) The transurethral dehiscence of the ostium is a therapeutic method which causes the spontaneous passage of incarcerated intramural ureteroliths.
(18) The sinus cavity was connected with the nasal cavity through an ostium.
(19) It is felt that the sphenoid mucocoele developed as a result of occlusion of the sinus ostium by scarred mucosa following radiotherapy.
(20) The left coronary artery had an anomalous origin; the left descending coronary artery originated from an independent ostium located at the right Valsalva sinus, the circumflex artery had its origin at the same ostium as the right coronary artery.