Intimal hyperplasia in the proximal portion of the right coronary artery was investigated by using longitudinal sections of the artery, to determine the amount of intimal and medial thickness, and the amount of deviation from the normal of the internal elastic lamina. One hundred and one samples in the 0-30 year age range were used and the results correlated with other known information about the individuals. Findings: 1. Intimal thickness increases directly as age increases. 2. There was a sex difference in the 16-30 year age group (males greater than females), but not under 15 years. 3. Intimal thickness increases significantly as the amount of internal elastic lamina change increases. 4. Medial thickness increases significantly with increasing age. 5. Intimal thickness increases significantly as medial thickness, heart mass and body mass increase, and increases at a more rapid rate than any of the three. 6. The amount of elastic lamina change increases significantly with age only between 1 and 30 years. These findings are correlated with the possible factors in the etiology of intimal hyperplasia. / Medicine, Faculty of / Graduate

In this thesis, the fatigue response of arteries to four specific physiological conditions representative of various morphological changes that artery undergo during its lifetime, was explored. Single layered nonlinear elastic micromechanical model of artery was developed for this purpose. A comparative study was completed on fatigue response, in the form of available life and shear stress accumulation, between hypertensive and normotensive arteries. The effects of morphological changes of ageing arteries on the fatigue response of the artery were studied. Change in stiffness, arterial dilation and remodeling were taken into consideration. The effect of undulation of the artery, due to weakening of arterial walls with age or hypertension, on fatigue response, is the third aspect of this study. Lastly, the contribution of the surrounding linear elastic tissue material on fatigue response of the artery was investigated to reflect the in-vivo condition of artery where it is always surrounded by different tissues.

Infra-inguinal arterial bypass is becoming increasingly popular as a means of alleviating incapacitating symptoms of atherosclerosis and other progressive diseases affecting the arteries of the lower limb. The role of this procedure in limb salvage is controversial but an aggressive attitude is emerging from many centres. It is accepted that the majority of atherosclerotic patients have a short life expectancy but reconstructive vascular surgery has an important role to play in improving their quality of life. Progress in infra-inguinal bypass surgery has centred mainly on the development of synthetic grafts but the perfonnance of autologous saphenous vein has not been bettered in terms of longterm results and cost-effectivity. The initial experience of infra-inguinal bypass at Groote Schuur Hospital, Cape Town, is examined retrospectively with the objective of demonstrating the possible influence of patient factors and specific surgical practices on the outcome of results.

Indiana University-Purdue University Indianapolis (IUPUI) / An exploratory study was conducted in order to identify what information patients have and/or want to have about an arteriogram prior to the procedure being performed, and to evaluate the effectiveness of a prearteriogram teaching program in providing this information. The final sample consisted of nine adult patients who were hospitalized and scheduled for arteriography (except for cerebral arteriograms). Data were collected over a two-and-a-half month period utilizing a prearteriogram and a postarteriogram questionnaire. Subjects were contacted prior to the arteriogram and asked to complete part of the prearteriogram questionnaire. The Singer Caramate (Model SP-2) was then used to present the prearteriogram teaching program (a cassette tape recording with accompanying slides) to the subjects. The program. provided the subjects with information about the arteriogram, including preparation for the procedure, how the procedure was performed, and postprocedural care. The subjects then completed the remainder of the prearteriogram questionnaire. Within 48 hours of the completion of the arteriogram the subjects were again contacted and asked to complete the postarteriogram questionnaire. Results of this study indicated that these subjects had very little, if any, information about the arteriogram prior to the procedure being performed, but that they did desire information about the preparation for the test, the procedure itself, and postprocedural care. Most of the subjects in the study indicated that they acquired information about the arteriogram from the prearteriogram teaching program, and that this program was helpful to them in preparing them for the arteriogram. The majority of the subjects also recommended that future patients scheduled for arteriograms be given this informati.on by presenting the program to them prior to the procedure. Thus, the investigator postulated that the presentation of information in an audio-visual program prior to an arteriogram is an effective means of providing information about the procedure to patients.

No description available.

No description available.

No description available.

No description available.

Naloxone (NX) potentiated epinephrine (EPI) induced submaximal vasoconstriction in canine renal and skeletal muscle arterial segments, yet had no vasoconstrictor action alone. Developed tension generated in-vitro by 4 x 1mm. O.D. rings from 1st degree branches of canine femoral arteries was expressed as % of KCI induced maximum response. NX (10^-5 M) potentiated EPI induced submaximal contractions (34.2%) significantly more than contractions induced by norepinephrine, phenylephrine, lofexidine, ADH, KCI and serotonin (13.8,13.4,4.7,13.5,14.4 and 11.4% respectively). The NX response was unaffected by beta-adrenergic blockade and NX did not reverse an isoproterenol mediated vasodilation. Alphaadrenergic blockade with phentolamine completely eliminated EPI plus NX induced vasoconstriction. After washout, vessels exposed to EPI plus NX relaxed by 50% significantly faster than vessels exposed to EPI alone (18.5 and 27.9 min respectively). EPI induced vasoconstrictions were potentiated by 10^-5 M corticosterone (49.0%) which inhibits extraneuronal catecholamine uptake, but not by 10^-7 M desipramine (1.1%) which inhibits neuronal uptake. EPI induced vasoconstrictions were also potentiated by 10^-4 M pyrogallol (33.0%) which inhibits catechol-o-methyl transferase activity, but not by 10^-5 M pargyline (-1.1%) which inhibits monoamine oxidase activity. The NX effect was endothelium independent. The dose-response of various opioid receptor agonists and antagonists were compared to the NX response. A specific opioid receptor subclass could not be identified as the mediator of the NX effect. The ED_50s for NX (3.7x^-6 M) and (+)NX (8.1x^-7M) indicated a significant stereoselectivity for the (+)enantiomer. A variety of sigma receptor ligands, steroids and steroid metabolites were tested for the ability to augment EPI vasoconstrictions. Several of the opioid, sigma and steroid ligands, all with polycyclic structures, induced responses similarto those of NX. NX exerted its effect independent of traditional opiate receptors and may have influenced the cellular uptake or degradation of EPI. Endogenous compounds with sigma or steroid activity may modulate these processes in-vivo.

Consequently, this study aims to develop novel technologies that can measure BP non invasively and continuously without a cuff. The proposed method estimates BP using features including pulse transit time (PTT), which is defined as the time interval from R wave of electrocardiogram to onset of photoplethysmogram within the same heart cycle. / Despite the importance of controlling blood pressure (BP) to our health, BP remains inadequately managed worldwide. Due to global ageing and change of human lifestyles, the number of hypertensives is anticipated to continue rising from approximately 1 billion in 2000 to 1.56 billion by 2025. A stumbling block to BP management is high BP usually develops without obvious symptoms. As a result, many people are unaware of their condition until severe problems such as a stroke, a heart attack or kidney failure have occurred. In China, over 100 million people do not know they have developed hypertension and are living under a potential risk to their health. In addition to high BP, variations of BP are also independent indicators of morbidity and mortality of severe diseases. Yet, sudden changes in BP are difficult to be detected by state-of-the-art BP meters, which operate on principles that require an inflatable cuff to give only a snapshot of BP. / Lastly, since the technology required information from several sensors that are placed on different body parts of a person, development of body area network (BAN) has been an important research focus. The concluding chapter of this thesis presents a new concept in this area, namely the hybrid body area network (h-BAN). In particular, the use of biological channels (bio-channels) for intra-BAN communication and securing wireless intra-BAN communication is discussed. / Nevertheless, a major challenge of this approach is its requirement of a calibration procedure. One possible solution is to calibrate against a cuff-based device, but this is inconvenient particularly when calibration has to be refreshed from time to time. Therefore, a bio-model is proposed and developed for PTT along an artery where the hydrostatic component of BP varies. The model can be applied to calibrate the cuffless PTT-based approach and estimate BP by simple movements such as hand elevation. Several experiments were conducted to validate the assumptions of this model and the results were found to be promising. / The proposed PTT-based technology was evaluated on 85 subjects (aged 57+/-29 yrs., including 39 hypertensives) whilst they were at rest in a sitting posture. A total of 999 pairs of systolic BP (SBP) and diastolic BP (DBP) estimations were made with reference to conventional cuff-based devices (i.e. a mercury sphygmomanometer and an oscillometric device) over a period of 6.4 weeks. The results of the study show that reference and estimated BP differed by 0.4+/-9.3 mmHg and 0.8+/-5.8 mmHg for SBP and DBP respectively (AAMI required mean and SD to be less than 5 and 8 mmHg correspondingly). / The results of both studies show that the accuracy of the PTT-based technique is comparable to the cuff-based approaches. This technique is potentially useful to measure BP continuously. / To conclude, this work developed a non-invasive and cuffless approach for BP measurement and addressed several key issues of this approach, i.e. the analysis, calibration, and implementation of it. The work can help to realise new BP management schemes in mobile health (m-Health) and personalised healthcare systems, which are developed to cater for the needs of the increasing aging population world-wide and to prevent and control chronic diseases like hypertension. / To further the investigation, a second study which was to investigate in a clinical setting for post-operation condition, was carried out on 8 patients (aged 55+/-18 yrs.) using the averaged invasive arterial-line and cuff readings taken at intervals of 40.0+/-24.7 min. as reference. After calibrating the new approach on each individual, it can estimate SBP and DBP within 3.3+/-6.5 mmHg and 4.3+/-6.4 mmHg of the reference for the complete set of 89 estimations. / Poon, Chung Yan Carmen. / "December 2007." / Adviser: Yuon-Ting Zhang. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4888. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 91-103). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.