The structural and functional changes of blood vessels during aging

The vascular adventitia is recognized as a dynamic mediator of vascular structure and function, yet its role in aging is not understood. The purpose of this thesis was to examine the age-related changes of the vascular adventitia and determine the underlying mediators responsible. Male Sprague-Dawley rats were aged to 15,30,50 and 80 weeks before being anesthetised and euthanized by exsanguination. Thoracic aortas, mesenteric and pudental arteries were isolated, formalin fixed, and embedded in paraffin then sectioned at 51lm. Vessels were examined by microscopy and protein expression was determined by indirect immunofluorescence. The thickness of the adventitia increased dramatically with age. Immunofluorescence revealed a robust expression of endothelin system proteins in the adventitia. Additionally, extracellular matrix proteins collagen and fibronectin, and the proliferation marker Ki67 showed strong adventitial origin. The changes observed in the vascular adventitia with aging clearly demonstrate an important role in the process of vascular aging.

Upper Lakes Shipping Ltd. Vessels Scrapbook, 1964-1967, no date

The origins of Upper Lakes Shipping can be traced back to 1931, when Gordon Leitch, the general manager of Toronto elevators, sent Captain Bruce Angus to scout for potential ships that could be used to transport grain. The ship Sarnian was purchased as a result. It soon became apparent that more ships would be needed by the business, and Leitch subsequently partnered with James Norris of the Norris Grain Company, in order to transport their products more economically. The Upper Lakes and St. Lawrence Transportation Company (which later become known as Upper Lakes Shipping), was incorporated in 1932. In 1956, the company bought Port Weller Dry docks. At this point, the company began constructing new vessels designed to meet specific freight and classification needs.

Statement of classes of vessels and merchandise passing downward through the Welland Canal during the year 1857

Statement of classes of vessels and merchandise passing downward through the Welland Canal during the year 1857 (Port Colborne), Jan. 30, 1862.

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1858

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1858 showing nationalities of ports of clearance and discharge, May 31, 1862.

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1859

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1859 showing nationalities of ports of clearance and discharge, June 29, 1862.

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1860

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1860 showing nationalities of ports of clearance and discharge, Jan. 29, 1862.

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1861

Statement of vessels and merchandise passed downward through the Welland Canal at Port Colborne during the year 1861 showing nationalities of ports of clearance and discharge. This is torn in a number of places and stained. This does not affect the text, Jan. 30, 1862.

Investment analysis of chemical projects and development of standerdised mathematical co-relation for cost estimation of pressure vessels in chemical industry

The present study is intended to provide a new scientific approach to the solution of the worlds cost engineering problems encountered in the chemical industries in our nation. The problem is that of cost estimation of equipments especially of pressure vessels when setting up chemical industries .The present study attempts to develop a model for such cost estimation. This in turn is hoped would go a long way to solve this and related problems in forecasting the cost of setting up chemical plants.

Lattice Boltzmann method for simulating the viscous flow in large distensible blood vessels

A lattice Boltzmann method for simulating the viscous flow in large distensible blood vessels is presented by introducing a boundary condition for elastic and moving boundaries. The mass conservation for the boundary condition is tested in detail. The viscous flow in elastic vessels is simulated with a pressure-radius relationship similar to that of the Pulmonary blood vessels. The numerical results for steady flow agree with the analytical prediction to very high accuracy, and the simulation results for pulsatile flow are comparable with those of the aortic flows observed experimentally. The model is expected to find many applications for studying blood flows in large distensible arteries, especially in those suffering from atherosclerosis. stenosis. aneurysm, etc.

p22phox C242T SNP inhibits inflammatory oxidative damage to endothelial cells and vessels

Background— T NADPH oxidase, by generating reactive oxygen species, is involved in the pathophysiology of many cardiovascular diseases and represents a therapeutic target for the development of novel drugs. A single-nucleotide polymorphism (SNP) C242T of the p22phox subunit of NADPH oxidase has been reported to be negatively associated with coronary heart disease (CHD) and may predict disease prevalence. However, the underlying mechanisms remain unknown. Methods and Results— Using computer molecular modelling we discovered that C242T SNP causes significant structural changes in the extracellular loop of p22phox and reduces its interaction stability with Nox2 subunit. Gene transfection of human pulmonary microvascular endothelial cells showed that C242T p22phox reduced significantly Nox2 expression but had no significant effect on basal endothelial O2.- production or the expression of Nox1 and Nox4. When cells were stimulated with TNFα (or high glucose), C242T p22phox inhibited significantly TNFα-induced Nox2 maturation, O2.- production, MAPK and NFκB activation and inflammation (all p<0.05). These C242T effects were further confirmed using p22phox shRNA engineered HeLa cells and Nox2-/- coronary microvascular endothelial cells. Clinical significance was investigated using saphenous vein segments from non CHD subjects after phlebectomies. TT (C242T) allele was common (prevalence of ~22%) and compared to CC, veins bearing TT allele had significantly lower levels of Nox2 expression and O2.- generation in response to high glucose challenge. Conclusions— C242T SNP causes p22phox structural changes that inhibit endothelial Nox2 activation and oxidative response to TNFα or high glucose stimulation. C242T SNP may represent a natural protective mechanism against inflammatory cardiovascular diseases.

Fractal structures in stenoses and aneurysms in blood vessels

Recent advances in the field of chaotic advection provide the impetus to revisit the dynamics of particles transported by blood flow in the presence of vessel wall irregularities. The irregularity, being either a narrowing or expansion of the vessel, mimicking stenoses or aneurysms, generates abnormal flow patterns that lead to a peculiar filamentary distribution of advected particles, which, in the blood, would include platelets. Using a simple model, we show how the filamentary distribution depends on the size of the vessel wall irregularity, and how it varies under resting or exercise conditions. The particles transported by blood flow that spend a long time around a disturbance either stick to the vessel wall or reside on fractal filaments. We show that the faster flow associated with exercise creates widespread filaments where particles can get trapped for a longer time, thus allowing for the possible activation of such particles. We argue, based on previous results in the field of active processes in flows, that the non-trivial long-time distribution of transported particles has the potential to have major effects on biochemical processes occurring in blood flow, including the activation and deposition of platelets. One aspect of the generality of our approach is that it also applies to other relevant biological processes, an example being the coexistence of plankton species investigated previously.

Xylella fastidiosa: An in vivo system to study possible survival strategies within citrus xylem vessels based on global gene expression analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morphometric study of placental villi and vessels in women with mild hyperglycemia or gestational or overt diabetes

In this study, morphometric measures of placental terminal villi and villous vessels were compared in overt, as well as gestational diabetes mellitus, and mild hyperglycemia diagnosed by oral 100 g glucose tolerance test (100 g-OGTT) and glucose profile (GP). At delivery (gestational age >= 34 weeks) a total of 207 placentas were assigned to a control group (n = 56) or to one of three groups complicated by mild hyperglycemia (n = 5 1), gestational diabetes (n = 59) and overt diabetes (n = 4 1). Placenta samples were randomly selected for blind morphometric assessment with an image analyser. Morphometric measures obtained included area and number of terminal villi and their respective villous vessels. Statistical analyses were performed using the chi-square test, ANOVA and stepwise regression (p <= 0.05). Glycemic means were 86.2 mg/dL in controls, 98.9 mg/dL in mild hyperglycemia, 114.1 mg/dL in gestational diabetes and 122.1 mg/dL in overt diabetes. Our results show that abnormal maternal glycemic levels may change the placental morphometric characteristics related to materno-fetal exchanges. (C) 2007 Elsevier B.V.. All rights reserved.