Cheung Ho Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 164-175). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.vi / Publications based on the work in this thesis --- p.vii / Table of content --- p.viii / Abbreviations --- p.xii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Traditional Chinese Medicine --- p.1 / Chapter 1.1.1 --- Danshen --- p.2 / Chapter 1.1.2 --- Chemical constituents --- p.5 / Chapter 1.1.3 --- Pharmacological effects --- p.7 / Chapter 1.1.3.1 --- On blood vessels --- p.7 / Chapter 1.1.3.2 --- On blood pressure --- p.8 / Chapter 1.1.3.3 --- On heart --- p.8 / Chapter 1.1.3.4 --- On myocardial ischaemia and reperfusion --- p.9 / Chapter 1.1.3.5 --- On platelet activity --- p.10 / Chapter 1.1.3.6 --- Other actions --- p.11 / Chapter 1.1.4 --- Clinical studies --- p.12 / Chapter 1.2 --- The Vascular System --- p.13 / Chapter 1.2.1 --- The circulation network --- p.13 / Chapter 1.2.2 --- Physiology of blood vessels --- p.13 / Chapter 1.2.3 --- Control of vascular lone --- p.14 / Chapter 1.3 --- Mechanisms of Vasodilatation --- p.16 / Chapter 1.3.1 --- Endothelium derived relaxant factors (EDRFs) --- p.16 / Chapter 1.3.1.1 --- Nitric oxide (NO) --- p.16 / Chapter 1.3.1.2 --- Prostacyclin (PGI：) --- p.17 / Chapter 1.3.1.3 --- Endotheliun-derived hyperpolarization factors (EDHFs) --- p.18 / Chapter 1.3.1.3.1 --- Epoxyeicosatrienoic acids (EETs) --- p.19 / Chapter 1.3.1.3.2 --- Potassium ion (IC) --- p.20 / Chapter 1.3.1.3.3 --- Gap junction --- p.20 / Chapter 1.3.2 --- Signal transduction pathways --- p.21 / Chapter 1.3.2.1 --- Guanylyl cyclase-cGMP pathway --- p.21 / Chapter 1.3.2.2 --- Adenylyl cyclase-cAMP pathway --- p.22 / Chapter 1.3.3 --- Ion channels in vascular smooth muscle cell --- p.24 / Chapter 1.3.3.1 --- Potassium channels (K+ channels) --- p.24 / Chapter 1.3.3.2 --- Calcium channels (Ca2+ channels) --- p.24 / Chapter 1.3.3.3 --- Chloride channel (Cl channel) --- p.25 / Chapter 1.3.4 --- Receptor-operated mechanisms --- p.27 / Chapter 1.3.4.1 --- Muscarinic receptors --- p.27 / Chapter 1.3.4.2 --- Adrenoceptors --- p.27 / Chapter 1.3.4.3 --- Histamine receptors --- p.28 / Chapter 1.3.4.4 --- CGRP receptors --- p.29 / Chapter 1.3.4.5 --- Tachykinin receptors --- p.30 / Chapter 1.4 --- Aims of the studies --- p.31 / Chapter CHAPTER 2 --- MATERIALS AND METHODS --- p.32 / Chapter 2.1 --- Extraction of Water and Lipid-solubie Fractions from Danshen --- p.32 / Chapter 2.1.1 --- Preparation of water-soluble and lipid-soluble fractions --- p.33 / Chapter 2.2 --- Experiments on Rat Knee Joint --- p.35 / Chapter 2.2.1 --- Animals --- p.35 / Chapter 2.2.2 --- Materials --- p.35 / Chapter 2.2.3 --- Preparatory protocols --- p.37 / Chapter 2.2.3.1 --- Anaesthesia of animals --- p.37 / Chapter 2.2.3.2 --- Cannulation of trachea --- p.37 / Chapter 2.2.3.3 --- Cannulation of carotid artery --- p.38 / Chapter 2.2.3.4 --- Blood pressure measurement --- p.38 / Chapter 2.2.4 --- Measurement of knee joint blood flow --- p.39 / Chapter 2.2.4.1 --- Preparation for measurement of knee joint blood flow --- p.41 / Chapter 2.2.5 --- Experimental protocols --- p.41 / Chapter 2.2.5.1 --- Danshen on knee joint blood flow --- p.41 / Chapter 2.2.5.2 --- Antagonists on Danshen --- p.41 / Chapter 2.2.5.3 --- Positive controls --- p.43 / Chapter 2.2.6 --- Image analysis --- p.44 / Chapter 2.2.7 --- Data analysis --- p.44 / Chapter 2.3 --- Experiments on Rat Femoral Artery --- p.45 / Chapter 2.3.1 --- Animals --- p.45 / Chapter 2.3.2 --- Materials --- p.45 / Chapter 2.3.2.1 --- Chemicals --- p.45 / Chapter 2.3.2.2 --- Physiological salt solution --- p.48 / Chapter 2.3.3 --- Preparatory protocols --- p.48 / Chapter 2.3.3.1 --- Small vessel myograph --- p.48 / Chapter 2.3.3.2 --- Isolation and mounting of tissue --- p.49 / Chapter 2.3.4 --- Experimental protocols --- p.50 / Chapter 2.3.4.1 --- Studies on the vasodilator response to Danshen --- p.50 / Chapter 2.3.4.2 --- Studies of antagonists on Danshen --- p.50 / Chapter 2.3.4.2.1 --- Endothelium-dependent mechanisms --- p.51 / Chapter 2.3.4.2.2 --- Endothelium-independent mechanisms --- p.54 / Chapter 2.3.4.2.3 --- K+ channel blockers --- p.54 / Chapter 2.3.4.2.4 --- Positive controls --- p.55 / Chapter 2.3.4.3 --- Danshen on Ca2+-induced contraction --- p.56 / Chapter 2.3.5 --- Data analysis --- p.57 / Chapter CHAPTER 3 --- RESULTS --- p.58 / Chapter 3.1 --- Danshen on Rat Knee Joint Blood Flow --- p.58 / Chapter 3.1.1 --- Topical administration of Danshen --- p.58 / Chapter 3.1.2 --- Antagonists on Danshen --- p.59 / Chapter 3.1.2.1 --- Muscarinic receptor antagonist --- p.59 / Chapter 3.1.2.2 --- β-adrenoceptor antagonist --- p.60 / Chapter 3.1.2.3 --- Histamine receptor antagonists --- p.60 / Chapter 3.1.2.4 --- Nitric oxide synthase inhibitor --- p.61 / Chapter 3.1.2.5 --- Cyclo-oxygenase inhibitors --- p.62 / Chapter 3.1.2.6 --- CGRPi receptor antagonist --- p.62 / Chapter 3.1.2.7 --- NK1 receptor antagonist --- p.63 / Chapter 3.1.2.8 --- Potassium channel inhibitor --- p.64 / Chapter 3.1.2.9 --- "Combination of cyclo-oxygenase inhibitor, nitric oxide synthase inhibitor and CGRP1 receptor antagonist" --- p.64 / Chapter 3.1.3 --- Antagonists on water-soluble fraction of Danshen --- p.91 / Chapter 3.1.3.1 --- Nitric oxide synthase inhibitor --- p.91 / Chapter 3.1.3.2 --- Cyclo-oxygenase inhibitors --- p.91 / Chapter 3.1.3.3 --- CGRP1 receptor antagonist --- p.92 / Chapter 3.1.3.4 --- NK1 receptor antagonist --- p.92 / Chapter 3.1.3.5 --- Potassium channel inhibitor --- p.92 / Chapter 3.2 --- Danshen on Rat Femoral Artery --- p.99 / Chapter 3.2.1 --- Danshen on precontracted arterial ring --- p.99 / Chapter 3.2.2 --- Endothelium-dependent mechanisms --- p.106 / Chapter 3.2.3 --- Endothelium-independent mechanisms --- p.114 / Chapter 3.2.4 --- K+ channel blockers --- p.119 / Chapter 3.2.4.1 --- Effect on Danshen --- p.119 / Chapter 3.2.4.2 --- Effect on water-soluble and lipid-soluble fractions of Danshen --- p.121 / Chapter 3.2.4.3 --- Effect on Danshensu --- p.122 / Chapter 3.2.5 --- Danshen on Ca2+-induced contractions --- p.133 / Chapter CHAPTER 4 --- DISCUSSION --- p.138 / Chapter 4.1 --- In Vivo Studies of Danshen on Rat Knee Joint Blood Flow --- p.139 / Chapter 4.2 --- In Vitro Studies of Danshen on Isolated Rat Femoral Artery --- p.148 / Chapter 4.2.1 --- Comparisons of the use of different precontractors --- p.148 / Chapter 4.2.2 --- Investigations on endothelium-dependent mechanisms --- p.151 / Chapter 4.2.3 --- Investigations on endothelium-independent mechanisms --- p.152 / Chapter 4.2.4 --- Effects of K+ channel blockers --- p.154 / Chapter 4.2.5 --- Inhibition of Ca2+ influx in vascular smooth muscle --- p.157 / Chapter 4.3 --- Comparisons of Results from In Vivo and In Vitro Studies --- p.159 / Chapter 4.4 --- Future Studies --- p.161 / Chapter 4.5 --- Conclusion --- p.162 / REFERENCES --- p.164

Objectives: To date little is known of the interaction between diabetes and sex hormones in the vasculature. A number of studies suggest that premenopausal diabetic women loose their gender based cardiovascular protection. However, there is insufficient evidence to explain the mechanism underlying the loss of this gender based cardioprotection in premenopausal diabetic women. The objectives of this study were to investigate whether there is a gender difference in the aortic endothelial function in · streptozotocin (STZ, 58 mg/kg, iv)-induced diabetic rats, and the potential role of superoxide and cyclooxygenase (COX) metabolites in diabetes-induced vascular dysfunction.

OBJECTIVE:Vascular smooth muscle cell (VSMC) hypertrophy and proliferation occur in response to strain-induced local and systemic inflammatory cytokines and growth factors which may contribute to hypertension, atherosclerosis, and restenosis. We hypothesize VSMC strain, modeling normotensive arterial pressure waveforms in vitro, results in attenuated proliferative and increased hypertrophic responses 48 hrs post-strain.METHODS:Using Flexcell Bioflex Systems we determined the morphological, hyperplastic and hypertrophic responses of non-strained and biomechanically strained cultured rat A7R5 VSMC. We measured secretion of nitric oxide, key cytokine/growth factors and intracellular mediators involved in VSMC proliferation via fluorescence spectroscopy and protein microarrays. We also investigated the potential roles of VEGF on VSMC strain-induced proliferation.RESULTS:Protein microarrays revealed significant increases in VEGF secretion in response to 18 hours mechanical strain, a result that ELISA data corroborated. Apoptosis-inducing nitric oxide (NO) levels also increased 43% 48 hrs post-strain. Non-strained cells incubated with exogenous VEGF did not reproduce the antimitogenic effect. However, anti-VEGF reversed the antimitogenic effect of mechanical strain. Antibody microarrays of strained VSMC lysates revealed MEK1, MEK2, phospo-MEK1T385, T291, T298, phospho-Erk1/2T202+Y204/T185+T187, and PKC isoforms expression were universally increased, suggesting a proliferative/inflammatory signaling state. Conversely, VSMC strain decreased expression levels of Cdk1, Cdk2, Cdk4, and Cdk6 by 25-50% suggesting a partially inhibited proliferative signaling cascade.CONCLUSIONS:Subjecting VSMC to cyclic biomechanical strain in vitro promotes cell hypertrophy while attenuating cellular proliferation. We also report an upregulation of MEK and ERK activation suggestive of a proliferative phenotype. Hhowever, the proliferative response appears to be aborogated by enhanced antimitogenic cytokine VEGF, NO secretion and downregulation of Cdk expression. Although exogenous VEGF alone is not sufficient to promote the quiescent VSMC phenotype, we provide evidence suggesting that strain is a necessary component to induce VSMC response to the antimitogenic effects of VEGF. Taken together these data indicate that VEGF plays a critical role in mechanical strain-induced VSMC proliferation and vessel wall remodeling. Whether VEGF and/or NO inhibit signaling distal to Erk 1/2 is currently under investigation.

The evaluation of retina structures has been of great interest because it could be used as a non-intrusive diagnosis in modern ophthalmology to detect many important eye diseases as well as cardiovascular disorders. A variety of retinal image analysis tools have been developed to assist ophthalmologists and eye diseases experts by reducing the time required in eye screening, optimising the costs as well as providing efficient disease treatment and management systems. A key component in these tools is the segmentation and quantification of retina structures. However, the imaging artefacts such as noise, intensity homogeneity and the overlapping tissue of retina structures can cause significant degradations to the performance of these automated image analysis tools. This thesis aims to provide robust and reliable automated retinal image analysis technique to allow for early detection of various retinal and other diseases. In particular, four innovative segmentation methods have been proposed, including two for retinal vessel network segmentation, two for optic disc segmentation and one for retina nerve fibre layers detection. First, three pre-processing operations are combined in the segmentation method to remove noise and enhance the appearance of the blood vessel in the image, and a Mixture of Gaussians is used to extract the blood vessel tree. Second, a graph cut segmentation approach is introduced, which incorporates the mechanism of vectors flux into the graph formulation to allow for the segmentation of very narrow blood vessels. Third, the optic disc segmentation is performed using two alternative methods: the Markov random field image reconstruction approach detects the optic disc by removing the blood vessels from the optic disc area, and the graph cut with compensation factor method achieves that using prior information of the blood vessels. Fourth, the boundaries of the retinal nerve fibre layer (RNFL) are detected by adapting a graph cut segmentation technique that includes a kernel-induced space and a continuous multiplier based max-flow algorithm. The strong experimental results of our retinal blood vessel segmentation methods including Mixture of Gaussian, Graph Cut achieved an average accuracy of 94:33%, 94:27% respectively. Our optic disc segmentation methods including Markov Random Field and Compensation Factor also achieved an average sensitivity of 92:85% and 85:70% respectively. These results obtained on several public datasets and compared with existing methods have shown that our proposed methods are robust and efficient in the segmenting retinal structures such the blood vessels and the optic disc.

Migrena - dažnas lėtinis susirgimas, kuris daugiausiai vargina jaunus žmones. Priepuolių metu dėl skausmo ir lydinčių reiškinių yra sutrikdoma ligonių kasdienė veikla. Be to, sergantiems migrena, o ypač migrena su aura, yra 2-3 kartus padidėjusi išeminių insultų, o taip pat kitų išeminių - kraujagyslinių komplikacijų rizika. Darbo tikslas buvo laikotarpyje tarp priepuolių nustatyti moterims, sergančioms migrena su aura (MA) ir be auros (M0), ryšį su bendraisiais kardiovaskulinės rizikos veiksniais, uždegiminių žymenų specifiškumu, ląstelinės hemostazės ypatumais bei su įvairaus diametro periferinių kraujagyslių endotelio funkcijos bei standumo kitimais. Ištyrėme 60 sveikų, 30 sergančių MA ir 30 M0. M0 moterims nustatytas didesnis sistolinis ir diastolinis kraujospūdis bei hipodinamija. Neįrodytos serumo amiloido A ir C reaktyvaus baltymo sąsajos su migrenos tipais, trombocitų funkcinio aktyvumo kitimais bei su įvairaus diametro periferinių kraujagyslių standumo ar endotelio funkcijos sutrikimais. Sergančiosioms migrena buvo padidėjęs trombocitų funkcinis aktyvumas, kuris priklausė nuo migrenos formos, M0 sergančiosioms ir nuo priepuolių dažnio Migrenos grupėje endotelio funkcija buvo sutrikusi tik mikrocirkuliacijoje. MA grupėje buvo didesnė tėkmės sąlygota dilatacija nei M0. Sergančiosioms migrena nustatytas susidarančių trombocitų monocitų agregatų tiesioginis ryšys su kitimais mikrocirkuliacijoje ir atvirkštinis ryšys su endotelio funkcija smulkiosiose periferinėse... [toliau žr. visą tekstą] / Migraine is a common chronic disease that is usually suffered by young people. During the attacks due to pain and other concomitant phenomena everyday activities of the patients are interrupted. Furthermore, people with migraine, especially with migraine with aura, are subject to 2-3 bigger risk of ischaemic stroke, as well as other ischaemc-blood vessel complications. The goal of the thesis is to determine the relation between migraine with aura (MA) and without aura (M0) (in women) and common cardiovascular risk factors, particularity of inflammatory markers, particularities of cellular hemostasis, as well as changes in functionality and stiffness of endothelium of peripheral blood vessels of various diameter during period between the attacks. 60 healthy women, as well as 30 with MA and 30 with M0 participated in the research. Higher systolic and diastolic blood pressure, as well as hypodynamia was registered in the M0 group. The relation between serum amyloid A, C reactive proteine and types of migraine, changes in functional activity of platelets and changes in functionality or stiffness of endothelium of peripheral blood vessels of various diameter was not proved. Women with migraine had an increased functional activity of platelets that depended on the type of migraine, frequency of attack and was more common in women with M0. In the migraine group endothelial function was unbalanced only in microcirculation. MA group demonstrated a higher flow-induced dilation than... [to full text]

The development of small-diameter artificial blood vessels that mimic the properties of natural blood vessels has proven to be a clinical challenge. While autologous vessels are the standard, they can be difficult to obtain and require invasive surgeries. Synthetic materials have been successful in large diameter applications, but they have been unsuccessful in small-caliber environments due to a number of factors including thrombus formation, intimal hyperplasia, and infection. Intimal hyperplasia, of particular interest in this study, involves the build up of smooth muscle cells (SMCs) in the intimal layer of the artery due to abnormal migration and proliferation. This work focuses on the development of a new polymer that has the potential to function as an intimal/medial component of a small-diameter blood vessel. Using recombinant elastin-like polypeptides (ELPs) developed by the Woodhouse laboratory, as well as chondroitin sulphate-specific binding sequences (CSBD1 and CSBD2) determined by the Panitch laboratory, a new elastin-like polypeptide-chondroitin sulphate binding domain (ELP-CSBD) block copolymer has been developed and characterized. The expression of the ELP1-CSBDs was accomplished using E. coli BL21 cells in a bioreactor or shaker flask systems. The polypeptides were purified using dialysis and ion exchange chromatography and expression and purity were characterized using mass spectrometry and amino acid analysis. Both ELP1-CSBDs were successfully expressed using these methods and ELP1-CSBD1 was produced to high purities. ELP1-CSBD1 was able to undergo coacervation in vitro, suggesting that ELP1-CSBD1 is able to self-assemble in a manner similar to native elastin. In the presence of the glycosaminoglycan chondroitin sulphate (CS), the temperature of coacervation of ELP1-CSBD1 is increased, the rate and extent of coacervation is decreased, and aggregates remain in solution even at higher temperatures. The influence of heparin was also explored as previous studies indicated that the CS binding domains were shown to also bind to heparin. Studies completed in the presence of heparin showed that there were no significant changes to the coacervation characteristics of ELP1-CSBD1. It is anticipated that when combined with CS, ELP1-CSBD1 will gel, forming a basis for an intimal/medial layer of a TEBV that will modulate SMC response and increase graft integrity. / Thesis (Master, Chemical Engineering) -- Queen's University, 2013-01-06 21:03:37.788

Medical imaging is an important part of the clinical workflow. With the increasing amount and complexity of image data comes the need for automatic (or semi-automatic) analysis methods which aid the physician in the exploration of the data. One specific imaging technique is angiography, in which the blood vessels are imaged using an injected contrast agent which increases the contrast between blood and surrounding tissue. In these images, the blood vessels can be viewed as tubular structures with varying diameters. Deviations from this structure are signs of disease, such as stenoses introducing reduced blood flow, or aneurysms with a risk of rupture. This thesis focuses on segmentation and visualization of blood vessels, consituting the vascular tree, in angiography images. Segmentation is the problem of partitioning an image into separate regions. There is no general segmentation method which achieves good results for all possible applications. Instead, algorithms use prior knowledge and data models adapted to the problem at hand for good performance. We study blood vessel segmentation based on a two-step approach. First, we model the vessels as a collection of linear structures which are detected using multi-scale filtering techniques. Second, we develop machine-learning based level set segmentation methods to separate the vessels from the background, based on the output of the filtering. In many applications the three-dimensional structure of the vascular tree has to be presented to a radiologist or a member of the medical staff. For this, a visualization technique such as direct volume rendering is often used. In the case of computed tomography angiography one has to take into account that the image depends on both the geometrical structure of the vascular tree and the varying concentration of the injected contrast agent. The visualization should have an easy to understand interpretation for the user, to make diagnostical interpretations reliable. The mapping from the image data to the visualization should therefore closely follow routines that are commonly used by the radiologist. We developed an automatic method which adapts the visualization locally to the contrast agent, revealing a larger portion of the vascular tree while minimizing the manual intervention required from the radiologist. The effectiveness of this method is evaluated in a user study involving radiologists as domain experts.

The purpose of this study was to identify the effects of a hemoglobin-based oxygen carrier, HBOC-201, on the cardiovascular system. Systemic cardiovascular parameters of mean arterial pressure (MAP), pulse pressure, heart rate, and oxygen saturation, as well as vascular resistance, were examined. A murine model of the cardiovascular system and microvasculature was employed. Sprague-Dawley rats (male; 230-530g; N = 13) were anaesthetised and surgically prepared for intravital microscopy of the spinotrapezius muscle. Increasing doses of HBOC-201 (2 mg/kg, 22 mg/kg, 230 mg/kg, and 780 mg/kg) and an iso-oncotic volume control were administered to assess for a dose-response relationship. MAP displayed a significant increase from baseline for both treatment groups, with no significant difference between the two. Arteriolar diameter displayed no changes from baseline, or between treatment groups or across doses. Based on these results, the noted changes in MAP were due to hypervolemia, and not a property of HBOC-201, itself.

Este estudo investigou o efeito da obesidade sobre a resposta de artérias mesentéricas a agonistas canabinóides. Ratos obesos Zucker (OZRs) apresentaram reduzido relaxamento à anandamida, aos agonistas CB1 e CB2 e à capsaicina (agonista vanilóide) comparados aos controles (LZRs). A expressão dos receptores CB1 e CB2 foi menor em OZRs. O bloqueio de canais de K+, a inibição da NOS, da COX ou do transporte de canabinóides reduziu a resposta à anandamida em LZRs. A resposta à anandamida em OZRs foi corrigida após: inibição da degradação de anandamida, ativação da via do cAMP e da AMPK, e inibição da ERK1/2. A anandamida aumentou a fosforilação da AMPK, da ACC e da eNOS em LZRs, mas reduziu em OZRs. A expressão da ERK1/2 fosforilada, maior em OZRs, foi potencializada pela anandamida. A obesidade diminui o relaxamento à anandamida por: reduzir a expressão de receptores CB1 e CB2; prejudicar respostas mediadas por receptores vanilóides; reduzir a captação e aumentar a degradação de anandamida; reduzir a ativação da AMPK e da eNOS e aumentar da ativação da ERK1/2. / This study aimed to investigate the effects of obesity on the response of mesenteric arteries to cannabinoid agonists. Obese Zucker rats (OZRs) displayed decreased relaxation to anandamide, to CB1 and CB2 agonists as well as to capsaicin (vanilloid agonist) compared to lean rats (LZRs). The CB1 and CB2 expression was decreased in OZRs. Anandamide response was decreased in LZRs after blockade of K+ channels and inhibition of NOS, COX or cannabinoid transport. Anandamide response in OZRs was corrected by: inhibition of anandamide degradation, activation of cAMP and AMPK pathway and inhibition of ERK1/2. Anandamide increased AMPK, ACC and eNOS phosphorylation in LZRs, but it reduced in OZRs. The expression of phosphorylated ERK1/2, increased in OZRs, was potentiated by anandamide. In conclusion, obesity decreases anandamide relaxation through: reduction of CB1 and CB2 receptors; impairment of signaling pathways mediated by vanilloid receptors; reduced uptake and increased degradation of anandamide; reduction of AMPK/eNOS activation and increase in ERK1/2 activation.

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