Global ETD Search

71	Mikrostimulátor / Microstimulator Tobolová, Marie January 2012 (has links) The theoretical part of the thesis deals with the explanation of the actions that occur during the stimulation of tissues with the electric current. A significant analogy with electrical circuits is used to describe the phenomena at the molecular and cellular level. The models of membrane and cell are necessary for understanding the behaviour of more complex structures, such as tissues and organs. A considerable attention is paid to the conditions of electrical stimulation which bring about response in the stimulated area. Next, the cumulative effect of the subthreshold stimulation is analysed. The mechanisms of common treatment effects of the electrotherapeutic methods are outlined. The research results in the practical part of the thesis – the design for a microstimulator. Properties of the microstimulator and compliance with standard requirements are verified by testing the electromagnetic compatibility and electrical safety, conducted by the Institute for testing and certification, JSC. The effects of microstimulation on living organisms are experimentally investigated on horses, in collaboration with the Veterinary and Pharmaceutical University. For the first time, thermodynamic sensors are used for the objective assessment of the microstimulation therapeutic effect. These miniature sensors are placed on the horse´s front legs and monitor the changes in thermal activity while only one limb is really stimulated and the other is just considered as a reference. Comparison and statistical evaluation of the measured signals could provide a more detailed view of the thermal changes within the stimulated area, which is significantly related to blood circulation in limbs, and with the support of the reduction of edema. The course of the experiment which deals with the effect of microstimulation on edema of the horse´s legs caused by minor injuries (tendinitis, sprains, etc.), is documented in photographs or videos that are significant for possible evaluation of the effectiveness of the stimulation in this application.
72	Relação entre a oferta e a utilização muscular periférica de oxigênio na transição do exercício leve para o intenso em pacientes com insuficiência cardíaca / Peripheral muscle oxygen delivery-to-utilization mismatch in the transition from mild to heavy-intensity exercise in patients with CHF Sperandio, Priscila Cristina de Abreu [UNIFESP] 24 November 2010 (has links) (PDF) Made available in DSpace on 2015-07-22T20:50:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-24. Added 1 bitstream(s) on 2015-08-11T03:26:10Z : No. of bitstreams: 1 Publico-12685a.pdf: 1258050 bytes, checksum: 53b17db1fdfbd3e4583d4358e7515aed (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:10Z : No. of bitstreams: 2 Publico-12685a.pdf: 1258050 bytes, checksum: 53b17db1fdfbd3e4583d4358e7515aed (MD5) Publico-12685b.pdf: 2009901 bytes, checksum: 92f9b67aa48fc3b5890595ab949a78a4 (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:10Z : No. of bitstreams: 3 Publico-12685a.pdf: 1258050 bytes, checksum: 53b17db1fdfbd3e4583d4358e7515aed (MD5) Publico-12685b.pdf: 2009901 bytes, checksum: 92f9b67aa48fc3b5890595ab949a78a4 (MD5) Publico-12685c.pdf: 2013198 bytes, checksum: 64df6a7e1d8d760785004ef7cb8107b9 (MD5) / Na insuficiencia cardiaca (IC) o comprometimento do fluxo sanguineo muscular na transicao do exercicio leve para o intenso pode reduzir temporariamente a pressao microvascular de O2 e diminuir a oferta de O2 do capilar para a mitocondria. No entanto, os avancos no tratamento medicamentoso da IC (por exemplo, os inibidores da enzima conversora de angiotensina e ƒÀ-bloqueadores de terceira geracao) poderiam ter melhorado a oferta microvascular de O2 a um ponto em que a lentidao da maquinaria metabolica intramuscular passaria a ser o fator limitante da resposta cinetica do consumo de oxigenio ( O2). O objetivo do presente estudo foi investigar a relacao dinamica entre oferta e utilizacao microvascular de O2 na transicao do exercicio leve (sem carga) para o intenso, em portadores de IC com tratamento otimizado e nao treinados, comparado a um grupo controle de individuos saudaveis. Foram incluidos 10 pacientes com IC com tratamento clinico otimizado (fracao de ejecao = 29 } 8%) e 11 controles pareados por idade. Avaliou-se as respostas cineticas da captacao pulmonar de O2 ( O2p), da extracao tissular de O2 no musculo vasto lateral, como estimada pela variacao na concentracao relativa de deoxihemoglobina + mioglobina (~ƒ¢[deoxi-Hb+Mb]), mensurada pelo metodo de espectroscopia de raios quasi-infravermelhos (NIRS) e do debito cardiaco (DC), durante exercicio de alta intensidade ate o limite de tolerancia (Tlim). A cinetica da O2p e do DC foram mais lentas nos pacientes com IC em comparacao aos controles e correlacionaram-se significativamente com menores valores de Tlim (P = 0,05). A cinetica total da ƒ¢[deoxi-Hb+Mb] foi mais rapida nos pacientes do que nos controles (tempo medio de resposta (MRT) = 15,9 } 2,0 s vs. 19,0 } 2,9 s; P = 0,05), com uma resposta de "overshoot" presente apenas nos pacientes (7/10). Alem disso, a razao t O2p/MRT-ƒ¢[deoxi-Hb+Mb] foi maior nos pacientes (4,69 } 1,42 s vs. 2,25 } 0,77 s; P < 0,05) e correlacionou-se com a cinetica do DC e o Tlim (R = 0,89 e 0,78, respectivamente; P = 0,01). Conclui-se que apesar dos avancos no tratamento medicamentoso da IC, os disturbios nos ajustes circulatorios "centrais" e "perifericos" continuam a desempenhar um papel proeminente na limitacao da cinetica da O2p e tolerancia a exercicio de alta intensidade em pacientes nao treinados com IC. / Impaired muscle blood flow at the onset of heavy-intensity exercise may transiently reduce microvascular O2 pressure and decrease the rate of O2 transfer from capillary to mitochondria in chronic heart failure (CHF). However, advances in the pharmacological treatment of CHF (e.g., angiotensin-converting enzyme inhibitors and third generation of â-blockers) may have improved microvascular O2 delivery to an extent that intramyocyte metabolic inertia might become the main locus of limitation of O2 uptake ( O2) kinetics. We included 10 optimally treated sedentary patients (ejection fraction = 29 ± 8%) and 11 age-matched controls. We assessed the rate of change of pulmonary O2 ( O2p), tissue O2 extraction in the vastus lateralis estimated by concentration of deoxy-hemoglobin+myoglobin (~Ä[deoxy-Hb+Mb]) measured by near-infrared spectroscopy (NIRS), and cardiac output ( T) during highintensity exercise performed to the limit of tolerance (Tlim). Sluggish O2p and T kinetics in patients were significantly related to lower Tlim values (P = 0.05). The dynamics of Ä[deoxy-Hb+Mb] were faster in patients than controls (mean response time (MRT) = 15.9 ± 2.0 s vs. 19.0 ± 2.9 s; P = 0.05) with a subsequent response “overshoot” being found only in patients (7/10). Moreover, t O2p/MRT-Ä[deoxy- Hb+Mb] ratio was greater in patients (4.69 ± 1.42 s vs. 2.25 ± 0.77 s; P = 0.05) and related to T kinetics and Tlim (R = 0.89 and 0.78, respectively; P = 0.01). We conclude that despite the advances in the pharmacological treatment of CHF, disturbances in “central” and “peripheral” circulatory adjustments still play a prominent role in limiting O2p kinetics and tolerance to heavy-intensity exercise in nontrained patients. / TEDE / BV UNIFESP: Teses e dissertações Cinética Hemodinâmica Insuficiência cardíaca Fluxo sanguíneo Humanos Exercício Oxigênio Circulação sanguínea Chronic heart failure Hemodynamics Near-infrared spectroscopy Oxygen consumption Blood flow Kinetics Heart Failure Humans Exercise Oxygen Spectroscopy, Near-Infrared Blood Circulation
73	Impaired cardiovascular responses to glucagon-like peptide 1 in metabolic syndrome and type 2 diabetes mellitus Moberly, Steven Paul 30 January 2013 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / Recent advancements in the management of systemic glucose regulation in obesity/T2DM include drug therapies designed to utilize components of the incretin system specifically related to glucagon-like peptide 1 (GLP-1). More recently, GLP-1 has been investigated for potential cardioprotective effects. Several investigations have revealed that acute/sub-acute intravenous administration of GLP-1 significantly reduces myocardial infarct size following ischemia/reperfusion injury and improves cardiac contractile function in the settings of coronary artery disease, myocardial ischemia/reperfusion injury, and heart failure. Despite an abundance of data indicating that intravenous infusion of GLP-1 is cardioprotective, information has been lacking on the cardiac effects of iv GLP-1 in the MetS or T2DM population. Some important questions this study aimed to address are 1) what are the direct, dose-dependent cardiac effects of GLP-1 in-vivo 2) are the cardiac effects influenced by cardiac demand (MVO2) and/or ischemia, 3) does GLP-1 effect myocardial blood flow, glucose uptake or total oxidative metabolism in human subjects, and 4) are the cardiac effects of GLP-1 treatment impaired in the settings of obesity/MetS and T2DM. Initial studies conducted in canines demonstrated that GLP-1 had no direct effect on coronary blood flow in-vivo or vasomotor tone in-vitro, but preferentially increased myocardial glucose uptake in ischemic myocardium independent of effects on cardiac contractile function or coronary blood flow. Parallel translational studies conducted in the humans and Ossabaw swine demonstrate that iv GLP-1 significantly increases myocardial glucose uptake at rest and in response to increases in cardiac demand (MVO2) in lean subjects, but not in the settings of obesity/MetS and T2DM. Further investigation in isolated cardiac tissue from lean and obese/MetS swine indicate that this impairment in GLP-1 responsiveness is related to attenuated activation of p38-MAPK, independent of alterations in GLP-1 receptor expression or PKA-dependent signaling. Our results indicate that the affects of GLP-1 to reduce cardiac damage and increase left ventricular performance may be impaired by obesity/MetS and T2DM. Obese-hyperglycemic syndrome Obesity Metabolic syndrome Glucans Glucose -- Synthesis Glucagon-like peptide 1 Diabetes -- Research Myocardial infarction Blood -- Circulation Blood flow -- Measurement Heart -- Left ventricle Heart function tests Myocardium Oxidation, Physiological
74	Peripheral Venous Retroperfusion: Implications for Critical Limb Ischemia and Salvage Kemp, Arika D. 12 1900 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / Peripheral arterial disease is caused by plaque buildup in the peripheral arteries. Standard treatments are available when the blockage is proximal and focal, however when distal and diffuse the same type of the treatment options are not beneficial due to the diseased locations. Restoration of blood flow and further salvaging of the limb in these patients can occur in a retrograde manner through the venous system, called retroperfusion or arteriovenous reversal. Retroperfusion has been explored over the last century, where early side to side artery to venous connections had issues with valve competency prohibiting distal flows, edema buildup, and heart failure. However, more recent clinical studies create a bypass to a foot vein to ensure distal flows, and though the results have been promising, it requires a lengthy invasive procedure. It is our belief that the concerns of both retroperfusion approaches can be overcome in a minimally invasive/catheter based approach in which the catheter is engineered to a specific resistance that avoids edema and the perfusion location allows for valves to be passable and flow to reach distally. In this approach, the pressure flow relations were characterized in the retroperfused venous system in ex-vivo canine legs to locate the optimal perfusion location followed by in-vivo validation of canines. Six canines were acutely injured for 1-3 hours by surgical ligation of the terminal aorta and both external iliac arteries. Retroperfusion was successfully performed on five of the dogs at the venous popliteal bifurcation for approximately one hour, where flow rates at peak pressures reached near half of forward flow (37±3 vs. 84±27ml/min) and from which the slope of the P/F curves displayed a retro venous vasculature resistance that was used to calculate the optimal catheter resistance. To assess differences in regional perfusion, microspheres were passed during retroperfusion and compared to baseline microspheres passed arterially prior to occlusion in which the ratio of retroperfusion and forward perfusion levels were near the ratio of reversed and forward venous flow (0.44) throughout the limb. Decreases in critical metabolites during injury trended towards normal levels post-retroperfusion. By identifying the popliteal bifurication as a perfusion site to restore blood flow in the entirety of the distal ischemic limb, showing reversal of injury, and knowing what catheter resistances to target for further chronic studies, steps towards controlled retroperfusion and thus more efficient treatment options can be made for severe PAD patients. Arteries -- Diseases Atherosclerotic plaque -- Research Blood flow -- Research Blood flow -- Measurement Dogs -- Anatomy -- Research Dogs -- Blood-vessels Ischemia -- Animal models Blood-vessels -- Abnormalities Hindlimb -- Abnormalities Tissue engineering -- Research Cardiovascular system -- Regeneration Blood -- Circulation Pressure -- Measurement Myocardial reperfusion Reperfusion (Physiology) Biomedical engineering -- Research Biomechanics
75	Preventing fatal effects of overworking : Product design solution Adawi, Rahim January 2018 (has links) “Overworking to death” is a phenomenon that has been noticeable in developing countries. The cause of death is mainly through ischemic strokes. While the victims’ occupations differed, they all shared a common characteristic, being positioned in a sedentary work, ranging from IT workers to doctors. This project’s aim was to develop a product that prevented or decreased the strokes that derived from sedentary overwork. This was mainly tackled by preventing one of the three causes of developing blood props, slowed blood flow. In order to gather rich data of the phenomenon, a qualitative study was conducted in China, during two months. By doing an extensive structured sampling, information rich data could be gathered during a short period of time. Data were derived from observations, questionnaires and an interview, which then was interpreted to customer needs and the final product specification. The final product became a trouser with an in built dynamic compression mechanic, that can compress the veins mostly during sitting activities, in order to prevent blood stasis. The compression mechanic works like the Chinese finger trap; compressing the calves while sitting and stretching the legs forward. It is made only out of polysaccharides fibres; cotton and corn. / "Guolaosi" eller död från överarbete är ett fenomen som i regel uppkommer bland utvecklingsländer. Dödsorsaken är huvudsakligen genom stroke. Offrens yrken varierar allt från professorer, IT-arbetare till läkare. De delar dock en sak gemensamt; att arbeta under långa perioder stillasittande. Projektets mål var att utveckla en produkt som minskar dödliga följderna av sedentära överarbete, genom att förebygga en av de tre orsakerna för att utveckla blodproppar; saktad blodström. Målgruppen var då kineser av de yrken som hade tidigare drabbats av fenomenet. För att samla informationsrika data om fenomenet genomfördes en kvalitativ studie i Kina under två månader. Genom att göra en omfattande strukturerad provtagning kunde informationsrika data samlas under en kort tidsperiod. Fältstudien bestod av observationer, frågeformulär och en intervju, som då tolkades till kundbehov och eventuellt produktspecifikationen. Den slutliga produkten kom att bli ett par byxor med en inbyggd dynamisk komprimeringsmekanism, som kan komprimera venerna under sittande aktiviteter, för att förhindra saktad blodström. Kompressionsmekanismen fungerar som den kinesiska fingerfällan. Den komprimerar blodkärlen medan personen sitter och sträcker benen framåt. Produkten är konstruerad på så sätt att den kan tillverkas endast av polysackariders tråd, från bomull och majs. Vilket är lämpligt för Kinas lokala resurser. stroke DVT overworking karoshi guolaosi prolonged inactivity sedentary death product design China Sweden Sida MFS field study trouser pants sampling observation questionnaire interview blood circulation stasis cardiovascular disease cotton corn agenda 2030 Chinese finger trap textile fibre yarn soil erosion muscle pump mechanism gradual compression stockings GECS PECS pressure distribution blood clot veins therapy stool chair PE PTS economy class syndrome methodology plastic sample concept sketch stroke DVT överarbete karoshi guolaosi förlängd inaktivitet stillasittande död produkt design Kina Sverige Sida MFS fältstudie byxa byxor provtagning observation frågeformulär intervju blodcirkulation stasis kardiovaskulär sjukdom bomull majs agenda 2030 kinesisk fingerfälla textil fiber garn jord erosion muskel pump mekanism gradvis komprimering strumpor stödstrumpa tryck kraft GECS PECS tryckfördelning blod blodproppar vener terapi pall stol PE PTS ekonomi klass syndrom metodik plast prov koncept skiss Design Design Pharmacology and Toxicology Farmakologi och toxikologi Occupational Therapy Arbetsterapi Cardiac and Cardiovascular Systems Kardiologi Environmental Sciences Miljövetenskap Medical Ergonomics Medicinsk ergonomi Textile, Rubber and Polymeric Materials Textil-, gummi- och polymermaterial Composite Science and Engineering Kompositmaterial och -teknik Medical Materials Medicinska material och protesteknik

Page generated in 0.365 seconds