The introduction of the scanning electron microscope into biological research has revolutionized the possibilities of studying the surface structures of biological specimens. The method was used originally for the surface of hard tissue ; however, the improved fixation method, which preserves quite well the ultrastructure of soft tissues as shown by Barber and Boyde (1968) ,1) has now made it possible to observe the fine structure of the surface of soft tissues.The present investigation is a study of the surface of vascular endothelium in the rabbit and man. These endothelia have already been studied by transmission electron microscopy, so their structure is partially known. This is the preliminary report of the study.
Materials and methods.The endothelial surface of aortas, coronary and renal arteries, inferior vena cavas, right and left ventricles and atria from 13 male rabbits and aortas, inferior vena cavas, right and left ventricles and atria of two men, 21 and 74 years old, who died of Crohn's disease and myeloma, respectively, were examined in the present study.The method of Barber and Boyde (1968)1) was modified and used. Namely, the isolated specimens were carefully washed by LockeRinger's solution, then 1 % osmium tetroxide (with veronal acetate to pH 7.4) was poured into the vessel lumen. The specimen was cut into small blocks 3 mm x 10 mm in size. The blocks were fixed for one hour under cold temperature in an ice-box and were dehydrated in graded Analar acetone solutions of 50%, 70%, 80%, 90%, 95%, and two changes of absolute acetone.After air drying, the specimens were mounted at an angle of 45° to an evaporation source and rotated during the deposition of a conducting coat of about 100300 A of gold in a vacuum.The specimens were studied with a scanning electron microscope (JSM-II) of Japan Electron Optics Laboratory Co. Ltd., using a beam accelerating voltage of 610 0 Ky. The micrograph recorded with a scanning electron beam on the film with an exposure time of 3060 seconds.
Purpose: We developed a method for ureteral stent exchange in female patients under fluoroscopic guidance using a crochet hook technique (CHEX). Patients and Methods: A total of 45 female patients (51 stents) underwent exchange of ureteral stents. In these patients, 21 ureteral stents were exchanged using CHEX. All procedures were carried out with the patients under conscious sedation. At the time of the procedures, we extracted the ureteral stent from the external urethral orifice using CHEX under fluoroscopic guidance and inserted the new stent under fluoroscopic guidance without cystoscopy. Results: 20 of the 21 stents (95.2%) were successfully exchanged. Ureteral stent exchange using CHEX was unsuccessful in 1 patient, including migration to the ureter. Conclusions: Ureteral stent exchange using a crochet hook is easy, safe and cost-effective. This technique was also easy to learn.
The fine structures of vascular endothelial surface with linear endothelial folds, were clearly shown by scanning and transmission electron microscopes in large arteries and veins of man and other mammals and the nuclear parts of endothelial cells were shown in the gullies in scanning electron microscopical observation.
The effects of substances promoting or inhibiting transendothelial leakage were studied in relation to these structures. Immediately after the challenge their nuclear parts were transiently enlarged and prolonged and the linear endothelial folds became irregular by edematous swelling of endothelial cells and subendothelial structures. Pyridinolcarbamate pretreatment prevented these changes.
Administration of cholesterol for 2 weeks induced edematous and spherical change of endothelial cells of aorta; and then localized flat lesions of endothelial cells with flattening of their degenerated nuclear parts in localized areas exposed to mechanical stress from the arterial blood stream. After 3 to 4 weeks the flat lesions changed into elevated lesions, fatty spots or streaks. These endothelial changes were significantly inhibited by pyridinolcarbamate.
At the margin of the elevated lesions, nuclear parts of the endothelial cells were exposed on the endothelial fold by elevation of gullies. The exposed nuclear part exhibited a highly deformed and swollen shape and such changes may be followed by an increase in local transendothelial infiltration resulting in expansion of elevated lesions. Chemical inJuries induce weakness of the resistance of endothelial cells and the mechanical stress from the arterial blood stream may aggravate the injury in a special area facing the strong mechanical stress from the blood stream. Summation of such injuries may initiate atherosclerosis in such a special area followed by expansion of atherosclerotic lesion to all directions.
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