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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vascular Corrosion Casting: Review of Advantages and Limitations in the Application of Some Simple Quantitative Methods

Hossler, Fred E., Douglas, John E. 01 May 2001 (has links)
Vascular corrosion casting has been used for about 40 years to produce replicas of normal and abnormal vasculature and microvasculature of various tissues and organs that could be viewed at the ultrastructural level. In combination with scanning electron microscopy (SEM), the primary application of corrosion casting has been to describe the morphology and anatomical distribution of blood vessels in these tissues. However, such replicas should also contain quantitative information about that vasculature. This report summarizes some simple quantitative applications of vascular corrosion casting. Casts were prepared by infusing Mercox resin or diluted Mercox resin into the vasculature. Surrounding tissues were removed with KOH, hot water, and formic acid, and the resulting dried casts were observed with routine SEM. The orientation, size, and frequency of vascular endothelial cells were determined from endothelial nuclear imprints on various cast surfaces. Vascular volumes of heart, lung, and avian salt gland were calculated using tissue and resin densities, and weights. Changes in vascular volume and functional capillary density in an experimentally induced emphysema model were estimated from confocal images of casts. Clearly, corrosion casts lend themselves to quantitative analysis. However, because blood vessels differ in their compliances, in their responses to the toxicity of casting resins, and in their response to varying conditions of corrosion casting procedures, it is prudent to use care in interpreting this quantitative data. Some of the applications and limitations of quantitative methodology with corrosion casts are reviewed here.
12

Evidence for a Unique Elastic Sheath Surrounding the Vesicular Arteries of the Rabbit Urinary Bladder - Studies of the Microvasculature With Microscopy and Vascular Corrosion Casting

Hossler, Fred E., Monson, Frederick C. 01 November 1998 (has links)
Because the urinary bladder stores and releases urine, its normal function includes filling and emptying, accompanied by distension and relaxation. It is known that chronic distension compromises blood flow. Recent studies of the rabbit bladder vasculature have described specializations of that vasculature that appear to enhance blood flow in the bladder wall during distension. The present report describes the location, orientation, and structure of an elastic sheath surrounding the vesicular arteries, which may represent one of these specializations. The location, vasculature, and structure of an accessory elastic sheath surrounding the vesicular arteries of the rabbit bladder is described using light and electron microscopy, India ink injection, and vascular corrosion casting. The common iliac arteries of rabbits were cannulated to permit perfusion of the distal vasculature including the urinary bladder. After the bladder vasculature was visually cleared of blood by perfusion with buffered saline, one of the following procedures was used: 1) for light or electron microscopy, the bladder was perfuse-fixed with buffered 2% glutaraldehyde; 2) the bladder vasculature was filled with India ink for vessel tracing; or 3) corrosion casts of the bladder vasculature were prepared by infusion of a Mercox resin mixture. Casts, cleaned of tissue with KOH, and water and formic acid rinses, are dried, and mounted for routine scanning electron microscopy. The presence of an accessory sheath surrounding the main vesicular arteries and some of their branches in the basal two thirds of the urinary bladder was observed on India ink injected specimens and confirmed by micrographs and vascular corrosion casts. The sheath consists of elastic and collagenous fibers and is separated from the tunica media of the arteries by a loose connective tissue layer of variable width. The sheath is circumscribed by a layer of fine blood vessels. The vesicular arteries undulate within the sheath to an extent which is dependent upon the degree of distension of the bladder. This sheath likely represents a specialization which permits the bladder vasculature to accommodate expansion and contraction of the wall during normal filling and emptying. Undulations or coiling of the vesicular arteries within the loose connective tissue core of the sheath increase with bladder contraction, and apparently the sheath simply holds the artery in position during such coiling. The sheath, may represent a modification of the external elastic lamina found in some muscular arteries.
13

Studium morfologie aneuryzmatu břišní aorty / Morphology of the Abdominal Aortic Aneurysm

Eberlová, Lada January 2013 (has links)
Dissertation Abstract Abdominalaortic aneurysm (AAA) is a serious disease. Its prevalence is in the developed countries about 3%. As an aneurysm is considered a dilatation of all layers of a vessel wall over 3 cm. Majority of AAA are small and asymptomatic, and although the risk of rupture increases with the size of aneurysm sack, even the small aneurysms rupture. The rupture mortaliry ranges about 70 %. Surgical treatment is indicated in the asymptomatic patients in diameter of AAA over 5 cm. The average speed of growth of AAA is 0.3 cm per year, e.g. in the early diagnosed patients there is a several years interval for a pharmacolocical influencing of the progression of this disease. Knowledge of pathogenesis is essential for any targeted pharmacological treatment. Our prospective, non-randomised studies are based on the application of the stereological methods for the histopathological assessment of the AAA samples. The acquired data enable the statistical analysis, including the null hypothesis testing. In our study analyzing the histopathology of AAA aortae of 65 patients (65 walls and 55 thrombi) and 6 normal abdominal aortae from the organ donors we assessed the following parameters: the area fractions of collagen and elastin, and the length density of elastin in intima and media, the area...
14

Studium morfologie aneuryzmatu břišní aorty / Morphology of the Abdominal Aortic Aneurysm

Eberlová, Lada January 2013 (has links)
Dissertation Abstract Abdominalaortic aneurysm (AAA) is a serious disease. Its prevalence is in the developed countries about 3%. As an aneurysm is considered a dilatation of all layers of a vessel wall over 3 cm. Majority of AAA are small and asymptomatic, and although the risk of rupture increases with the size of aneurysm sack, even the small aneurysms rupture. The rupture mortaliry ranges about 70 %. Surgical treatment is indicated in the asymptomatic patients in diameter of AAA over 5 cm. The average speed of growth of AAA is 0.3 cm per year, e.g. in the early diagnosed patients there is a several years interval for a pharmacolocical influencing of the progression of this disease. Knowledge of pathogenesis is essential for any targeted pharmacological treatment. Our prospective, non-randomised studies are based on the application of the stereological methods for the histopathological assessment of the AAA samples. The acquired data enable the statistical analysis, including the null hypothesis testing. In our study analyzing the histopathology of AAA aortae of 65 patients (65 walls and 55 thrombi) and 6 normal abdominal aortae from the organ donors we assessed the following parameters: the area fractions of collagen and elastin, and the length density of elastin in intima and media, the area...

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