Motivated by the physiological phenomena of collapse and flow limitation for a serial pulmonary artery stenosis, we investigated the three-dimensional influence of spatial configuration on the wall motion and hemodynamic. Our numerical study focused on the effect of two geometrical parameters: the relative distance and the angular orientation between the two stenoses. The collapse of a compliant arterial stenosis may cause flow choking, which would limit the flow reserve to major vital vascular beds such as the lungs, potentially leading to a lethal ventilation-perfusion mismatch. Flow through a stenotic vessel is known to produce flow separation downstream of the throat. The eccentricity of a stenosis leads to asymmetric flow where the high velocity jets impinge on the sidewall, thereby inducing significant dissipation. The additional viscous dissipation causes a higher pressure drop for a flow through a stenotic vessel, than in a straight compliant vessel. It is likely that some particular morphology would have a higher vulnerability to the fluid induced instability of buckling (divergence), under physiological pulsatile flow. It was found that fluid pressure distribution have substantial implication for the downstream wall motion, under conditions of strong coupling between nonlinear vessel geometries, and their corresponding asymmetric flow. The three-dimensional fluid structure interaction problem is solved numerically by a finite element method based on the Arbitrary Lagrangian Eulerian formulation, a natural approach to deal with the moving interface between the flow and vessel. The findings of this investigation reveal that the closeness between stenoses is a substantial indication of wall collapse at the downstream end. Moreover, the results suggest a close link between the initial angular orientation of the distal stenosis (i.e. the constriction direction) and the subsequent wall motion at the downstream end. For cases showing evidence of preferential direction of wall motion, it was found that the constricted side underwent greater cumulative displacement than the straight side, suggestive of significant wall collapse.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [195]-230).

Orientador: Fabíola Taufic Monica Iglesias / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T12:19:02Z (GMT). No. of bitstreams: 1 Gonzalez_PauloGabriel_M.pdf: 1495536 bytes, checksum: 26ccc94133bf9c2af38d1a3c267493c1 (MD5) Previous issue date: 2014 / Resumo: É bem estabelecido que a acetilcolina (ACh) produz relaxamento da musculatura lisa vascular através da liberação endotelial do óxido nítrico (NO) e, portanto, é uma das ferramentas farmacológicas mais utilizadas para avaliar a integridade do endotélio. Experimentos preliminares feito pelo nosso grupo mostraram que a ACh não relaxou a aorta e nem artéria pulmonar de sagui (Callithrix jacchus), além de induzir contração neste último leito em vaso com endotélio íntegro. Assim, o presente estudo teve como objetivo caracterizar de maneira mais detalhada a resposta colinérgica em artéria pulmonar de sagui. Em artéria pulmonar, O ADP (0.01-100 µM) produziu relaxamento dependente da concentração, que foi reduzido a aproximadamente 42% na presença do L-NAME (100 ?M) ou da indometacina (inibidor não seletivo da cicloxigenase, 10 ?M). A ACh (0.00001-1 mM) induziu contração dependente da concentração com valores de potência (pEC50) e resposta maxima (Emax) de 5.83 ± 0.08 and 90 ± 5%, respectivamente. A Emax da ACh aumentou aproximadamente 28% e 22% na presença de L-NAME e após a remoção do endotélio, respectivamente. Os antagonistas muscarínicos mais seletivos para os subtipos M2 e M3, metoctramina e 4-DAMP, e a indometacina reduziram significativamente a contração induzida pela ACh. A estimulação elétrica (4-16 Hz, 80 V, 10 segundos de estimulação) induziu contração dependente da frequência que foi significativamente reduzida na presença de 4-DAMP (0.1 µM), metoctramina (0.1 µM) e fentolamina (10 ?M) e aumentada pela fisostigmina (10 µM). Na presença de hexametônio (1 ?M), fentolamina (10 µM) ou tetrodotoxina (1 ?M) a contração mediada pela ACh não foi alterada. A análise de imunofluorescência revelou a presença da colina acetiltransferase (ChAt) na tunica media. Estes dados mostram a presença de uma inervação colinérgica excitatória em artéria pulmonar de Callithrix jacchus / Abstract: It is well established that acetylcholine (ACh) produces relaxation of vascular smooth muscle by endothelial release of nitric oxide (NO) and thus is one of the most widely used pharmacological tools to assess the integrity of the endothelium. Preliminary experiments done by our group showed that ACh did not relax the aorta and pulmonary artery of marmoset (Callithrix jacchus), and induces contraction in the latter bed in vessel with intact endothelium. Thus, the present study aimed to characterize in more detail the cholinergic response in pulmonary artery marmoset. In pulmonary artery ADP (0.01-100 µM) produced concentration-dependent relaxation which was reduced to approximately 42% in the presence of L-NAME (100 µM) and indomethacin (nonselective cyclooxygenase inhibitor, 10 µM). ACh (0.00001-1mM) produced concentration-dependent contractions with potency values (pEC50) and maximum response (Emax) of 5.83 ± 0:08 and 90 ± 5%, respectively. The Emax of ACh increased by approximately 28% and 22% in the presence of L-NAME and after removal of the endothelium, respectively. The muscarinic antagonists more selective for subtypes M2 and M3, methoctramine and 4-DAMP, and indomethacin significantly reduced ACh-induced contraction. Electrical field stimulation (EFS 4-16 Hz, 80 V, 10 seconds of stimulation) induced frequency-dependent contraction, which was significantly reduced in the presence of 4-DAMP (0.1 µM), methoctramine (0.1 µM) and phentolamine (10 µM) and augmented by physostigmine (10 µM). In the presence of hexamethonium (1 µM), phentolamine (10 µM) or tetrodotoxin (1 µM) contraction mediated by ACh was not altered. The immunofluorescence analysis revealed the expression of choline acetyltransferase (Chat) in Tunica Media. These data show the presence of an excitatory cholinergic innervation in the pulmonary artery Callithrix jacchus / Mestrado / Farmacologia / Mestre em Farmacologia

No description available.

Right-heart catheterization is the most accurate method for estimating pulmonary artery pressure (PAP). Because it is an invasive procedure it is expensive, exposes patients to the risk of infection, and is not suited for long-term monitoring situations. Medical researchers have shown that PAP influences the characteristics of heart sounds. This suggests that heart sound analysis is a potential noninvasive solution to the PAP estimation problem. This thesis describes the development of a prototype system, called PAPEr, which estimates PAP noninvasively using heart sound analysis. PAPEr uses patient data with machine learning algorithms to build models of how PAP affects heart sounds. Data from 20 patients was used to build the models and data from another 31 patients was used as a validation set. PAPEr diagnosed these 31 patients for pulmonary hypertension with an accuracy of 77 percent.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

A quantitative research design for a descriptive and contextual study to determine the critical care nurses knowledge and data preferences regarding the central venous and pulmonary artery catheters management and decision making after coronary arte.y bypass graft operations and the utmzation period of the pulmonary artery catheter after coronary artery bypass graft operations. The data was collected through a questionnaire completed by critical care nurses and retrospective analysis of patient records through a structured checklist. Data analysis indicated the following: critical care nurses have a knowledge deficit in the management of the central venous and pulmonary artery catheters and felt more competent and confident in the central venous measurements. The utilization period of the pulmonary artery catheter was 48% compared to the 100% of the central venous catheter. / Advanced Nursing Science / M.A. (Advanced Nursing Science)

A quantitative research design for a descriptive and contextual study to determine the critical care nurses knowledge and data preferences regarding the central venous and pulmonary artery catheters management and decision making after coronary arte.y bypass graft operations and the utmzation period of the pulmonary artery catheter after coronary artery bypass graft operations. The data was collected through a questionnaire completed by critical care nurses and retrospective analysis of patient records through a structured checklist. Data analysis indicated the following: critical care nurses have a knowledge deficit in the management of the central venous and pulmonary artery catheters and felt more competent and confident in the central venous measurements. The utilization period of the pulmonary artery catheter was 48% compared to the 100% of the central venous catheter. / Advanced Nursing Science / M.A. (Advanced Nursing Science)

Wu Min. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 87-114). / Abstracts in English and Chinese. / Declaration --- p.i / Acknowledgement --- p.ii / Publication list --- p.iii / Abstract (English) --- p.xi / Abstract (Chinese) --- p.xiv / Abbreviations --- p.xvi / List of figures / tables --- p.xviii / Chapter Chapter 1. --- General Introduction --- p.1 / Chapter 1.1 --- Endothelial function in the regulation of vascular tone --- p.1 / Chapter 1.1.1 --- NO --- p.2 / Chapter 1.1.2 --- PGI2 --- p.5 / Chapter 1.1.3 --- EDHF --- p.6 / Chapter 1.2 --- Alteration of endothelial functions after preservation with cardioplegia /organ preservation solutions in the coronary and pulmonary microcirculations --- p.18 / Chapter 1.2.1 --- Cardioplegia/organ preservation solutions --- p.21 / Chapter 1.2.2 --- Effect of Cardioplegia/organ preservation solutions on endothelial function --- p.22 / Chapter 1.2.2.1 --- Effect of K+ on endothelial function --- p.23 / Chapter 1.2.2.2 --- Effect of other components on endothelial function --- p.24 / Chapter Chapter 2. --- Materials and Methods --- p.26 / Chapter 2.1 --- Isometric force study in coronary/pulmonary resistance arteries --- p.26 / Chapter 2.1.1 --- Preparation of vessels --- p.26 / Chapter 2.1.1.1 --- Preparation of porcine coronary small arteries --- p.26 / Chapter 2.1.1.2 --- Preparation of porcine pulmonary small arteries --- p.26 / Chapter 2.1.2 --- Technique of setting up --- p.29 / Chapter 2.1.2.1 --- Mounting of small vessels --- p.29 / Chapter 2.1.2.2 --- Normalization procedure for small vessels --- p.29 / Chapter 2.1.3 --- EDHF-mediated vasorelaxation --- p.30 / Chapter 2.1.3.1 --- Precontraction and stimuli of EDHF --- p.30 / Chapter 2.1.3.2 --- """True"" response of EDHF" --- p.31 / Chapter 2.1.4 --- Data acquisition and analysis --- p.32 / Chapter 2.2 --- Electrophysiological study --- p.32 / Chapter 2.2.1 --- Preparation of small porcine coronary/pulmonary arteries --- p.32 / Chapter 2.2.2 --- Preparation of microelectrode --- p.32 / Chapter 2.2.3 --- Impaling of microelectrode --- p.33 / Chapter 2.2.4 --- Recording of membrane potential --- p.33 / Chapter 2.3 --- Statistical analysis --- p.34 / Chapter 2.4 --- Chemicals --- p.34 / Chapter Chapter 3. --- Effects of Celsior Solution on Endothelial Function in Resistance Coronary Arteries Compared to St. Thomas' Hospital Solution --- p.37 / Chapter 3.1 --- Abstract --- p.37 / Chapter 3.2 --- Introduction --- p.38 / Chapter 3.3 --- Experimental design and analysis --- p.40 / Chapter 3.3.1 --- Vessel preparation --- p.40 / Chapter 3.3.2 --- Normalization --- p.40 / Chapter 3:3.3 --- "Relaxation study: BK-induced, EDHF-mediated relaxation" --- p.41 / Chapter 3.3.4 --- Cellular electrophysiological study: EDHF-mediated cellular hyperpolarization and associated relaxation --- p.41 / Chapter 3.3.5 --- Data analysis --- p.42 / Chapter 3.4 --- Results --- p.43 / Chapter 3.4.1 --- Relaxation study --- p.43 / Chapter 3.4.1.1 --- Resting force --- p.43 / Chapter 3.4.1.2 --- U46619-induced precontraction --- p.43 / Chapter 3.4.1.3 --- EDHF-mediated relaxation --- p.43 / Chapter 3.4.2 --- Electrophysiological studies --- p.44 / Chapter 3.4.2.1 --- Resting membrane potential --- p.44 / Chapter 3.4.2.2 --- EDHF-mediated cellular hyperpolarization --- p.45 / Chapter 3.4.2.3 --- Cellular hyperpolarization-associated relaxation --- p.45 / Chapter 3.5 --- Discussion --- p.46 / Chapter 3.5.1 --- Effects of Celsior solution on endothelial function --- p.47 / Chapter 3.5.2 --- Effects of ST solution on EDHF-mediated function --- p.48 / Chapter 3.5.3 --- Comparison between Celsior and ST solutions on EDHF-mediated function --- p.48 / Chapter 3.5.4 --- Clinical implications --- p.49 / Chapter Chapter 4. --- Effects of Perfadex and Celsior Solution on Endothelial Function in Resistance Pulmonary Arteries --- p.57 / Chapter 4.1 --- Abstract --- p.57 / Chapter 4.2 --- Introduction --- p.58 / Chapter 4.3 --- Experimental design and analysis --- p.59 / Chapter 4.3.1 --- Vessel Preparation --- p.59 / Chapter 4.3.2 --- Normalization --- p.60 / Chapter 4.3.3 --- Isometric force study --- p.60 / Chapter 4.3.4 --- Electrophysiological studies --- p.61 / Chapter 4.3.5 --- Data analysis --- p.61 / Chapter 4.4 --- Results --- p.62 / Chapter 4.4.1 --- Relaxation study: EDHF-mediated relaxation --- p.62 / Chapter 4.4.1.1 --- Resting force --- p.62 / Chapter 4.4.1.2 --- U46619-induced precontraction --- p.62 / Chapter 4.4.1.3 --- EDHF-mediated relaxation --- p.62 / Chapter 4.4.2 --- Electrophysiological studies --- p.63 / Chapter 4.4.2.1 --- Resting membrane potential --- p.63 / Chapter 4.4.2.2 --- EDHF-mediated cellular hyperpolarization --- p.64 / Chapter 4.4.2.3 --- Cellular hyperpolarization-associated relaxation --- p.64 / Chapter 4.5 --- Discussion --- p.65 / Chapter 4.5.1 --- Effects of Celsior solution on endothelial function during cardiopulmonary surgery --- p.65 / Chapter 4.5.2 --- Effects of Perfadex solution on EDHF-mediated endothelial function --- p.66 / Chapter 4.5.3 --- Comparison between Celsior and Perfadex solutions on EDHF-mediated function --- p.66 / Chapter 4.5.4 --- Clinical implications --- p.67 / Chapter Chapter 5. --- Exploration of the Nature of EDHF - the Effect of H2O2 on the Membrane Potential in the Rat Small Mesenteric Arteries --- p.73 / Chapter Chapter 6. --- General Discussion --- p.75 / Chapter 6.1 --- EDHF-mediated endothelial function in porcine coronary and pulmonary circulation --- p.75 / Chapter 6.1.1 --- Role of EDHF in the regulation of porcine coronary arterial tone --- p.75 / Chapter 6.1.2 --- Role of EDHF in the regulation of porcine pulmonary arterial tone --- p.76 / Chapter 6.2 --- Alteration of EDHF-mediated endothelial functions after exposure to organ preservation solutions --- p.77 / Chapter 6.2.1 --- Effects of hyperkalemic solution on EDHF-mediated endothelial function in coronary and pulmonary circulation --- p.78 / Chapter 6.2.2 --- Effects of low-potassium-based preservation solution on EDHF-mediated endothelial function in pulmonary circulation --- p.79 / Chapter 6.2.3 --- Comparison between hyperkalemic solution and low-potassium-based preservation solution on EDHF-mediated endothelial function --- p.80 / Chapter 6.2.4 --- Effects of other component of organ preservation solutions on EDHF-mediated endothelial function --- p.81 / Chapter 6.3 --- Clinical implications --- p.82 / Chapter 6.4 --- The effect of H202 on the membrane potential in rat small mesenteric arteries --- p.83 / Chapter 6.5 --- Limitation of the study --- p.84 / Chapter 6.6 --- Future investigations --- p.85 / Chapter 6.7 --- Conclusions --- p.85 / References --- p.87

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Primary pulmonary hypertension (PPH) has an extremely poor prognosis with a mean survival time of 2‐3 years from time of diagnosis. Hemodynamically, PPH is defined with a mPAP of ≥ 25 mm Hg. Currently, RHC is the gold standard for measuring the arterial pressures and diagnosing PPH; however, it is an incredibly invasive procedure. Our study will show whether CT angiography can be considered as a non‐invasive alternative for diagnosing PPH. Studies in the past have shown CT measurements of the MPAD and MPAD/AAD ratio having strong correlations with PPH. In addition to those measurements, we want to show if other CT parameters also have a correlation with PPH. Some of these novel measurements include the interventricular septal deviation and the Elizabeth Taylor sign. The interventricular septum is normally bowing to the right in a non‐pathological state. If it is straight or bowing to the left, this will indicate increased right ventricular pressures which would be indicative of PPH. Straight will indicate increased RV pressures, and bowing to the left will be considered markedly increased RV pressures. The Elizabeth Taylor sign is the ratio of the diameter of the segmental bronchi and its corresponding artery. We will hypothesize that the artery will be much larger than the bronchi in patients with PPH. Other measurements will include the left and right pulmonary arteries. This study is a retrospective review of subjects who underwent an otherwise unremarkable CT pulmonary artery angiogram. Subjects with pulmonary embolism or other acute pulmonary diseases are excluded. For each subject, the following CT findings are obtained: main pulmonary artery diameter (mPAD), ratio of mPAD to ascending aorta, right and left pulmonary artery diameters, ratio of segmental pulmonary artery to corresponding bronchus, and interventricular septal displacement. Straightening of the interventricular septum qualifies as increased right ventricular septal pressure and right‐to‐left bowing of the septum qualifies as a marked increase. Mean pulmonary artery pressure measured on any prior/subsequent RHC or echocardiogram within 3 months of the CT is recorded. Any past medical history of connective tissue disease is noted. Descriptive data are calculated and correlations are done to assess for presence and strength of associations among variables. Data from 484 subjects are collected. Incidence rate of pulmonary hypertension isv13% (n=63). 52% (n=33) of the subjects with pulmonary hypertension are female with an average age of 55 years. mPA diameter (p<0.001), mPA:AA ratio (p<0.001), right (p<0.001) and left pulmonary artery (p=0.004) diameters are predictors of pulmonary hypertension. sPA:B ratio (p=0.08) and interventricular septal displacement (p=0.96) are not predictive of pulmonary hypertension. This study supports an association of mPA diameter, mPA:AA ratio, right and left pulmonary artery diameters with pulmonary hypertension diagnosed by RHC or echocardiogram. Prospective research is warranted to confirm and establish threshold values for each variable. Currently, an invasive RHC remains the most accurate method of diagnosis. Correlating CT findings with pulmonary hypertension would allow clinicians to use CT as a noninvasive screening tool.