• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 168
  • 32
  • 23
  • 23
  • 11
  • 6
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 297
  • 297
  • 297
  • 63
  • 62
  • 58
  • 51
  • 41
  • 40
  • 32
  • 28
  • 26
  • 25
  • 24
  • 23
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

糖尿病心血管併發症發生時間的推算 / Time estimation of occurrence of diabetes-related cardiovascular complications

胡晴媛 January 2011 (has links)
University of Macau / Institute of Chinese Medical Sciences
262

Vascular endothelial and smooth muscle function in children at risk of cardiovascular disease and the effect of folic acid supplementation.

Peña Vargas, Alexia Sophie January 2008 (has links)
Cardiovascular disease secondary to atherosclerosis is the most common cause of human morbidity and mortality. An early and fundamental event in the development of atherosclerosis is abnormal vascular endothelial and smooth muscle function. This can be measured by flow mediated dilatation and glyceryl trinitrate mediated dilatation in children at risk of atherosclerosis. Folic acid improves endothelial function (flow mediated dilatation) in adults with coronary artery disease. No studies have previously investigated the effects of folic acid on vascular function in at risk children with diabetes or obesity. In a cross sectional study an evaluation of vascular endothelial and smooth muscle function and their determinants was performed in 159 children with type 1 diabetes, 58 children with obesity, and 53 healthy children. Children with type 1 diabetes and children with mild to moderate obesity had comparable and severe vascular dysfunction but different determinants. Vascular function in healthy and obese children related to both body mass index and weight (adjusted for age and sex), and blood glucose. Children with obesity had lower folate levels and higher homocysteine levels than children with type 1 diabetes, an abnormal lipid profile and raised inflammatory markers. A randomised double blind placebo controlled cross over trial of 8 weeks of folic acid supplementation was performed in 38 children with type 1 diabetes. In these children, folic acid improved endothelial function with a sustained increase in folate levels but independent of homocysteine levels. Folic acid did not improve smooth muscle function. A randomised double blind placebo controlled parallel trial of 8 weeks folic acid supplementation was performed including 53 obese children. Folic acid did not improve vascular function in obese children in spite of sustained increase in folate levels, and a decrease in homocysteine levels. It was concluded that children with type 1 diabetes and obesity have comparable and severe endothelial and smooth muscle function. Determinants of vascular function in children, including weight and glucose, represent a continuum effect. Folic acid supplementation improved endothelial function in children with type 1 diabetes but not in children with obesity, whose metabolic changes causing endothelial dysfunction differ from children with diabetes. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1317003 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2008
263

Development of a culturally sensitive program delivering cardiovascular health education to indigenous Australians, in South-West towns of Western Australia with lay educators as community role models

Owen, Julie January 2006 (has links)
[Truncated abstract] Indigenous Australians suffer cardiovascular disease (CVD) at a rate six times greater than the general population in Australia and while the incidence of CVD has been reduced dramatically amongst the majority of non-indigenous Australians and amongst Indigenous populations in other countries in the last 30 years, there has been little change in the figures for Aboriginal Australians, showing that heart health campaigns have little impact, for this group of people. Aims : The principal aims of this study were firstly, to determine and record the barriers to the development and delivery of CVD prevention programs amongst Indigenous Australians and secondly, to develop an alternative, effective and culturally sensitive method of delivering heart health messages. Methods and results : The study was qualitative research undertaken in three South-West towns of Western Australia where the incidence of CVD was high amongst the Aboriginal community members. The use of semi-formal interviews, informal individual consultation, observation, and focus groups were methods implemented to obtain information. The first phase of the research was to identify the barriers which affected the Aboriginal Health Workers’ ability to deliver specialist educational programs. Questionnaires and interviews with the Aboriginal Health Workers and other health professionals in the towns, and community focus groups were undertaken in this phase of the study. The second phase of the research was aimed at developing an alternative strategy for delivering heart health messages. The focus changed to adopt more traditional ways of passing on information in Indigenous communities. The idea of small gatherings of friends or family with a trusted community member presenting the health message was developed. The third phase of the research was to implement this new approach. Lay educators who had been identified within focus groups and by Aboriginal Health Workers were trained in each of the towns and a protocol involving discussions of health issues, viewing a video on CVD, produced by the National Heart Foundation, sharing in a ‘heart healthy’ lunch and partaking in a ‘heart health’ knowledge game which was developed specifically for the gatherings. Several of these gatherings were held in each of the towns and they became known as ‘HeartAware parties’.
264

Investigating key factors that influence quality of life in implantable cardioverter defibrillator patients in the cardiac clinic at Groote Schuur Hospital

Luscombe, Anna Louisa 02 1900 (has links)
Text in English / International studies have demonstrated that Implantable Cardioverter Defibrillators (ICDs) can have a significant impact on the Quality of Life (QOL) of patients. This is often due to factors that cause considerable psychological distress and has not been investigated in South Africa before. This research study thus investigated factors that influence QOL in patients with ICDs who are followed up in the Cardiac Clinic at Groote Schuur Hospital. The objectives were to describe demographic, clinical, ICD and patient support characteristics; to determine the prevalence of anxiety and depression; to assess QOL and to establish factors that influence depression, anxiety and QOL. The method involved a quantitative approach and a descriptive, cross-sectional and correlational design. All eligible patients with ICDs from the Cardiac Clinic were invited to participate. Participants completed a Demographic and Clinical Questionnaire, the Hospital Anxiety and Depression Scale (HADS) and the SF-36v2 Health Survey. A descriptive analysis of frequencies and summary statistics were done, followed by a regression, comparison and correlational analyses. A total of 70 patients (57 years mean, 65% male) participated in the study. The HADS mean score for anxiety was 6.50, SD 4.52 and for depression 4.96, SD 3.36. The SF-36v2 QOL Physical Component Summary (PCS) mean score was 43.83, SD 9.43 and the Mental Component Summary (MCS) was 47.81, SD 10.71. Factors associated with depression, anxiety and poor QOL included having more than 5 ICD shocks (appropriate or inappropriate). Patients who felt that the ICD influenced their lifestyle positively, was 10.46 times more like to have mental well-being. This study showed that patients with ICDs managed in the state sector, is a vulnerable population. They often live far from hospital, have a high unemployment rate and a poor income. The HADS revealed that 21.4% of the patients had depressive symptoms and 28.6% fulfilled criteria for anxiety. The SF-36v2 revealed that the QOL of patients with ICDs was significantly lower than the norm, with regard to their physical and mental well-being. The study highlights the need for psychological and social support of patients living with ICDs. Keywords: quality of life; implantable cardioverter defibrillator; sudden cardiac death; arrhythmia; anxiety; depression; HADS; SF36v2. / Psychology / M.A. (Psychology)
265

Impacto de intervenção nutricional no controle dos níveis pressóricos e metabólicos de pacientes hipertensos em acompanhamento na atenção primária de saúde do município de São Luís MA / Impact of nutritional intervention in the control of blood pressure and metabolic monitoring in hypertensive patients in primary health care in São Luís - MA

Silvia Tereza de Jesus Rodrigues Moreira Lima 18 March 2013 (has links)
A hipertensão é uma das principais causas de morbidade e mortalidade no Brasil. Os hipertensos muitas vezes apresentam perfil lipídico e glicidico desfavoráveis. A alimentação pode desempenhar um papel importante na redução da pressão arterial (PA) e no perfil lipídico e controle glicêmico desses pacientes. Avaliar o impacto de uma intervenção nutricional adaptada ao padrão alimentar brasileiro no controle dos níveis pressóricos e metabólico de pacientes hipertensos em acompanhamento em um serviço de atenção primária de saúde do município de São Luís do Maranhão. Metodologia: ensaio clínico randomizado utilizando uma dieta de baixo índice glicêmico combinada ao aumento do consumo de frutas, vegetais, grãos integrais e laticínios desnatados que são os princípios do Dietary Approach to Stop Hypertension (dieta DASH). Foram alocados randomicamente 206 pacientes hipertensos que foram acompanhados por 6 meses. O grupo controle (GC, n=101) recebeu aconselhamento padrão, focado na redução da ingestão de sal. Resultados: Dos 206 pacientes randomizados, 156 (37 homens, 119 mulheres) completaram o estudo. A idade média dos participantes foi de 60,1 (DP 12,9) anos. Após 6 meses, houve redução na média da pressão arterial sistólica (PAS) em 14,4 mmHg e na diastólica (PAD) de 9,7 mmHg no grupo experimental (GE), em comparação a 6,7 mmHg e 4,6 mmHg, respectivamente, no GC. Após o ajuste para mudança de peso corporal, PA na linha de base e idade, essas diferenças entre os grupos foram de aproximadamente 9,2 mmHg e 6,2 mmHg, respectivamente. Ocorreram tambem variações estatisticamente significantes na excreção urinária de sódio, reduzida em 43,4 mEq/24 h no GE, bem como o colesterol total (-46.6mg/dl) , LDL colesterol (-42.5mg/dl), triglicérides (-31.3mg/dl), glicemia de jejum (-9.6mg/dl ) e hemoglobina glicada (-0,1%). O consumo alimentar modificou-se no GE com aumento do consumo de vegetais, passando de 2,97 para 5,85 ; frutas (4,09-7,18); feijão (1,94-3,13) e peixes (1,80 para 2,74). Modificações importantes relacionadas à redução significativa de carboidratos, teor lipídico e carga glicêmica da dieta, foram observadas. Conclusão: Este estudo mostrou a viabilidade e a eficácia de uma abordagem dietética com base no padrão alimentar brasileiro, na redução da PA e parâmetros bioquímicos inadequados, podendo causar um grande impacto na saúde pública. / Hypertension is one of the leading causes of morbidity and mortality in Brazil. Hypertensive patients often have unfavorable lipid profile and glucose level. Nutrition may play an important role in reducing blood pressure (BP) and metabolic control of these patients. Objective: To evaluate the impact of nutritional intervention adapted to the Brazilian food in controlling blood pressure and metabolic monitoring in hypertensive patients from a primary care service in São Luís do Maranhão. Methodology: Randomized clinical trial using a low-glycemic index diet combined with increased consumption of fruits, vegetables, whole grains and nonfat dairy products which principles of the Dietary Approach to Stop Hypertension (DASH). We randomly assigned 206 patients with hypertension who were followed for 6 months. The control group (CG, n = 101) received standard counseling, focused on reducing salt intake. Results: Of the 206 patients randomized, 156 (37 men, 119 women) completed the study. The average age of participants was 60.1 (SD 12.9) years. After 6 months, a reduction in mean systolic blood pressure (SBP) by 14.4 mmHg and diastolic blood pressure (DBP) by 9.7 mmHg in the experimental group (EG), compared to 6.7 mmHg and 4.6 mmHg, respectively GC. After adjusting for change in body weight at baseline BP and age, these differences between groups were approximately 9,2 mmHg and 6,2 mmHg, respectively. There were also statistically significant variability in urinary sodium excretion, reduced by 43.4 mEq/24 h at GE, as well as total cholesterol (-46.6mg/dl), LDL cholesterol (-42.5mg/dl), triglycerides (-31.3 mg / dl), fasting glucose (-9.6mg/dl) and glycated hemoglobin (-0.1%). The EG increased the intake of vegetables, from 2.97 to 5.85; fruits (4,09 to 7.18), beans (1.94 to 3.13) and fish (1.80 to 2.74).Significant changes related to the significant reduction of carbohydrate, lipid content and glycemic load of the diet have been observed. Conclusion: This study showed the feasibility and effectiveness of a dietary approach based no Brazilian pattern in reducing blood pressure and biochemical parameters. Dietary changes as proposed may have a great impact on public health.
266

Impacto de intervenção nutricional no controle dos níveis pressóricos e metabólicos de pacientes hipertensos em acompanhamento na atenção primária de saúde do município de São Luís MA / Impact of nutritional intervention in the control of blood pressure and metabolic monitoring in hypertensive patients in primary health care in São Luís - MA

Silvia Tereza de Jesus Rodrigues Moreira Lima 18 March 2013 (has links)
A hipertensão é uma das principais causas de morbidade e mortalidade no Brasil. Os hipertensos muitas vezes apresentam perfil lipídico e glicidico desfavoráveis. A alimentação pode desempenhar um papel importante na redução da pressão arterial (PA) e no perfil lipídico e controle glicêmico desses pacientes. Avaliar o impacto de uma intervenção nutricional adaptada ao padrão alimentar brasileiro no controle dos níveis pressóricos e metabólico de pacientes hipertensos em acompanhamento em um serviço de atenção primária de saúde do município de São Luís do Maranhão. Metodologia: ensaio clínico randomizado utilizando uma dieta de baixo índice glicêmico combinada ao aumento do consumo de frutas, vegetais, grãos integrais e laticínios desnatados que são os princípios do Dietary Approach to Stop Hypertension (dieta DASH). Foram alocados randomicamente 206 pacientes hipertensos que foram acompanhados por 6 meses. O grupo controle (GC, n=101) recebeu aconselhamento padrão, focado na redução da ingestão de sal. Resultados: Dos 206 pacientes randomizados, 156 (37 homens, 119 mulheres) completaram o estudo. A idade média dos participantes foi de 60,1 (DP 12,9) anos. Após 6 meses, houve redução na média da pressão arterial sistólica (PAS) em 14,4 mmHg e na diastólica (PAD) de 9,7 mmHg no grupo experimental (GE), em comparação a 6,7 mmHg e 4,6 mmHg, respectivamente, no GC. Após o ajuste para mudança de peso corporal, PA na linha de base e idade, essas diferenças entre os grupos foram de aproximadamente 9,2 mmHg e 6,2 mmHg, respectivamente. Ocorreram tambem variações estatisticamente significantes na excreção urinária de sódio, reduzida em 43,4 mEq/24 h no GE, bem como o colesterol total (-46.6mg/dl) , LDL colesterol (-42.5mg/dl), triglicérides (-31.3mg/dl), glicemia de jejum (-9.6mg/dl ) e hemoglobina glicada (-0,1%). O consumo alimentar modificou-se no GE com aumento do consumo de vegetais, passando de 2,97 para 5,85 ; frutas (4,09-7,18); feijão (1,94-3,13) e peixes (1,80 para 2,74). Modificações importantes relacionadas à redução significativa de carboidratos, teor lipídico e carga glicêmica da dieta, foram observadas. Conclusão: Este estudo mostrou a viabilidade e a eficácia de uma abordagem dietética com base no padrão alimentar brasileiro, na redução da PA e parâmetros bioquímicos inadequados, podendo causar um grande impacto na saúde pública. / Hypertension is one of the leading causes of morbidity and mortality in Brazil. Hypertensive patients often have unfavorable lipid profile and glucose level. Nutrition may play an important role in reducing blood pressure (BP) and metabolic control of these patients. Objective: To evaluate the impact of nutritional intervention adapted to the Brazilian food in controlling blood pressure and metabolic monitoring in hypertensive patients from a primary care service in São Luís do Maranhão. Methodology: Randomized clinical trial using a low-glycemic index diet combined with increased consumption of fruits, vegetables, whole grains and nonfat dairy products which principles of the Dietary Approach to Stop Hypertension (DASH). We randomly assigned 206 patients with hypertension who were followed for 6 months. The control group (CG, n = 101) received standard counseling, focused on reducing salt intake. Results: Of the 206 patients randomized, 156 (37 men, 119 women) completed the study. The average age of participants was 60.1 (SD 12.9) years. After 6 months, a reduction in mean systolic blood pressure (SBP) by 14.4 mmHg and diastolic blood pressure (DBP) by 9.7 mmHg in the experimental group (EG), compared to 6.7 mmHg and 4.6 mmHg, respectively GC. After adjusting for change in body weight at baseline BP and age, these differences between groups were approximately 9,2 mmHg and 6,2 mmHg, respectively. There were also statistically significant variability in urinary sodium excretion, reduced by 43.4 mEq/24 h at GE, as well as total cholesterol (-46.6mg/dl), LDL cholesterol (-42.5mg/dl), triglycerides (-31.3 mg / dl), fasting glucose (-9.6mg/dl) and glycated hemoglobin (-0.1%). The EG increased the intake of vegetables, from 2.97 to 5.85; fruits (4,09 to 7.18), beans (1.94 to 3.13) and fish (1.80 to 2.74).Significant changes related to the significant reduction of carbohydrate, lipid content and glycemic load of the diet have been observed. Conclusion: This study showed the feasibility and effectiveness of a dietary approach based no Brazilian pattern in reducing blood pressure and biochemical parameters. Dietary changes as proposed may have a great impact on public health.
267

Exposure of endothelial cells to physiological levels of myeloperoxidase modified LDL delays pericellular fibrinolysis and reduces cell motility

Daher, Jalil 10 March 2014 (has links)
Cardiovascular diseases are considered the first cause of death in westernized societies. They are directly linked to atherosclerosis, a clinical condition characterized by a thickening of the arterial wall. Atherosclerosis is in his turn linked to various genetic and environmental factors; among those factors are high oxidized LDL levels and endothelial dysfunction. In the present study, we have analyzed in vitro the effect of myeloperoxidase oxidized LDL on endothelial cells at the level of fibrinolysis and cell motility.<p>In the first part of the work, we measured fibrinolysis in real time at the surface of endothelial cells. Our results suggest that myeloperoxidase oxidized LDL interferes with the regulation of fibrinolysis by endothelial cells by decreasing their pro-fibrinolytic activity. This effect was not related to a modification in expression of major regulators of fibrinolysis such as PAI-1 and t-PA. Our data link the current favorite hypothesis that oxidized LDL has a causal role in atheroma plaque formation with an old suggestion that fibrin may also play a causal role. A model that best explains our results would be as follows: oxidized LDL increases fibrin deposition on endothelial cells which will increase their permeability resulting in more oxidized LDL infiltration into the subendothelial space of the arterial wall initiating atherogenesis. <p>In the second part of the work, we investigated the effect of myeloperoxidase oxidized LDL at the level of endothelial cell motility. We have shown that oxidized LDL is able to decrease cell migration, wound healing and tubulogenesis in endothelial cells. Those effects were not associated with any alteration at the level of neither cell viability nor proliferation. Subsequent gene expression analyses enabled us to link the oxidized LDL induced phenotypical changes in the cells to a change in expression of both microRNA-22 and Heme Oxygenase 1 genes. Our observations suggest a novel role of oxidized LDL not only as an important factor in the initiation of atheromatous lesions, but also as a potential player in the progression of the atherosclerosis disease by impeding blood vessel repair and wound healing at the sites of lesions.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
268

Contribution à l'étude de la réponse hémodynamique lors d'exercices de renforcement musculaire: sujets sains et patients de réadaptation cardio-vasculaire

Lamotte, Michel 12 September 2011 (has links)
\ / Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished
269

Coronary heart disease prevention in healthy coronary-prone individuals

Webster, Sharon 23 August 2012 (has links)
D.Litt. et Phil. / This research investigated the effectiveness of the treatment programme used by the South African Recurrent Coronary Prevention Project (SARCPP) in reducing the risk of not only recurrent heart disease, but also of original occurrence of heart disease. Heart disease can often be attributed to lifestyle factors such as obesity, high fat content diets and smoking (Friedman & Ulmer, 1995 and Richards & Baker, 1988). Another lifestyle risk factor of heart disease is Type A behaviour, as first discovered by Rosenman and Friedman (1959). Type A behaviour is made up of various components, such as hostility, time urgency and insecurity. The SARCPP has effectively reduced Type A behaviour in past studies (Venter, 1993; Viljoen, 1993; MacLennan, 1994 and Webster, 1994) and it has been found that reducing Type A behaviour through this programme increases high density lipoproteins and decreases total triglycerides, thus decreasing physiological risk factors of heart disease (Wolff, Thoresen, Viljoen, & Venter, 1994). The SARCPP thus far had only been used with Type A persons who had already suffered a form of heart disease, such as myocardial infarction and angina pectoris (here called "unhealthy" Type As). Other interventions have been used to decrease Type A behaviour in subjects who had not yet suffered heart disease (or "healthy" Type As). A leading researcher in this field is Ethel Roskies (1979-1990). Due to ineffective measurement and ineffective treatment programmes, her attempts were not successful, though. This research study applied the treatment used in the SARCPP to both "healthy" and "unhealthy" Type As and it was found that it was as successful in reducing Type A behaviour in both the "healthy" subjects as in the "unhealthy" subjects. Not only was global Type A behaviour as measured by the Videotaped Structured Interview decreased in the treatment groups, but so were the components of Hostility, Time Urgency and Insecurity (although Insecurity was not decreased in the "unhealthy" subjects). The tendency by the subjects to repress angry feelings was reduced in both "unhealthy" and "healthy" subjects, as was cynical hostility in the "healthy" subjects. It was found that the "unhealthy" subjects had significantly more State and Trait anxiety before the treatment took place than the "healthy" subjects and that the treatment reduced that anxiety in the "unhealthy" subjects significantly. Depression was decreased in both "healthy" and "unhealthy" subjects. Thus, the treatment programme of the SARCPP was effective in reducing coronary-prone behavioural factors and can be used as both prevention in recurrence and prevention in original occurrence of heart disease.
270

Mécanismes des maladies cardiovasculaires chez le sujet noir africain: le vieillissement artériel précoce serait-il un déterminant ?

Lemogoum, Daniel 05 January 2015 (has links)
RESUME DES TRAVAUX<p><p>La rigidification des gros troncs artériels (GTA) est physiologiquement liée à l’âge et s’accélère sous l’influence de certains facteurs de risque cardiovasculaire tels que l’hypertension artérielle (HTA), le diabète, le tabagisme, la dyslipidémie, l’obésité, la consommation excessive de sel, la sédentarité et l’hérédité. Le vieillissement artériel prématuré est un déterminant majeur du risque d’événements cardiovasculaires. Il se caractérise par une altération des propriétés élastiques des GTA, consécutive à l’épaississement de l’intima et surtout de la média se traduisant par une rigidification de leur paroi et une intensification de la réflexion de la courbe de pression aortique. Une artère rigide accélère la vitesse de propagation de l’onde de pouls (VOP) qui en est le marqueur direct et induit par conséquent un retour plus précoce des ondes de pression réfléchies de la périphérie vers l’aorte.<p>Nous avons testé l’hypothèse que le risque accru de maladies cardiovasculaires (MCV) documenté chez les sujets noirs africains serait lié en partie au vieillissement précoce de leurs artères et que son amplification chez les bantous serait largement attribuable aux facteurs environnementaux.<p>A cet effet, nous avons procédé dans un premier temps à la validation de la VOP, de la pression pulsée (pression systolique-pression diastolique) et de l’index d’augmentation de pression (AIx), tous deux dérivés de la courbe de pression aortique comme méthodes de mesure et d’évaluation non invasive de la distensibilité artérielle chez les sujets normotendus. Nos résultats révèlent que la stimulation bêta-adrénergique non cardio-sélective par l’isoproterenol atténue de façon significative la réflexion des ondes de pression aortique et augmente nettement la pression pulsée (PP) aortique alors que la VOP aortique qui constitue la mesure de référence de l’élasticité artérielle n’est pas affectée. Ces résultats suggèrent dès lors que la PP et l’AIx ne sont pas des marqueurs fiables de la rigidité artérielle lors de la stimulation bêta-adrénergique.<p><p>Nous avons ensuite évalué l’amplitude de cet effet de l’isoproterenol sur la paroi artérielle du sujet noir africain. C’est ainsi que nous avons observé que la stimulation bêta-adrénergique par l’isoproterenol engendre une accélération de la VOP aortique chez les sujets noirs, contrairement aux sujets caucasiens chez qui elle la ralentit considérablement. Ce résultat suggère que l’altération précoce des propriétés structurelles et fonctionnelles de la paroi aortique des sujets noirs sous l’effet de divers stress pourrait contribuer à la sévérité et à la précocité des MCV couramment rapportées au sein de ce groupe ethnique.<p><p>Nous avons ensuite testé une série d’hypothèses nécessitant des mesures non invasives de l’élasticité artérielle au sein de populations particulières au Cameroun.<p>C’est ainsi que nous avons investigué l’effet de l’anémie falciforme sur la rigidité artérielle et la réflexion de la courbe de pression aortique. L’hypothèse testée était que les complications cardiovasculaires couramment rapportées chez les drépanocytaires seraient dues à l’altération des propriétés viscoélastiques de leur paroi artérielle. Cette seconde partie de nos travaux nous a permis de démontrer que les patients drépanocytaires souffrant de la forme homozygote d’anémie falciforme (SS) ont des artères centrales aortiques très souples et des artères périphériques musculaires moins rigides. En effet, leur VOP est ralentie et leurs ondes de réflexion de la périphérie vers l’aorte sont fortement atténuées en comparaison aux contrôles sains (AA). L’anémie falciforme et la pression artérielle moyenne (PAM) sont apparues comme étant des déterminants indépendants de l’état d’élasticité aortique dans notre population d’étude (SS et AA). Cette étude a révélé toutefois une accélération paradoxale des VOP radiale et aortique dans les zones de basse pression artérielle, suggérant un effet délétère vasculaire de l’hypotension artérielle sévère chronique sur la paroi aortique.<p><p>Enfin, dans le troisième volet de notre travail, nous avons évalué l’effet du mode de vie chasseurs-pêcheurs-cueilleurs sur l’état d’élasticité aortique des pygmées traditionnels (TP) Camerounais. Nos travaux révèlent que ces TP ont des artères plus élastiques illustrées par une faible accélération de leur VOP aortique, comparée à celles des pygmées contemporains (CP) et des agriculteurs bantous partageant le même environnement semi-urbain et soumis tous à un mode de vie de type occidental. Fait important, cette faible accélération de la VOP aortique des TP est indépendante de la PAM et de leur âge chronologique qui en constituent pourtant des déterminants majeurs classiques bien documentés. Par contre, cette différence d’élasticité aortique entre TP, CP et bantous s’estompe nettement après correction pour le poids corporel.<p>Dans le même ordre d’idées, nous avons également démontré qu’en dépit de leur petite taille, les pygmées traditionnels réfléchissent leurs ondes de pression de la périphérie vers l’aorte avec une amplitude similaire à celle des pygmées contemporains et des bantous semi urbains.<p><p> <p>Conclusion.<p>Les résultats de nos travaux confortent la VOP comme marqueur de référence de la rigidité artérielle et suggèrent un vieillissement précoce de l’aorte chez les sujets noirs pouvant expliquer en partie la sévérité et la précocité des MCV couramment rapportées chez eux. Ce phénomène s’illustre notamment par l’accélération de la VOP aortique induite par l’isoproterenol chez les sujets noirs africains contrairement aux sujets caucasiens, chez qui la stimulation bêta-adrénergique par isoproterenol s’accompagne d’un ralentissement considérable de la VOP aortique. Cependant, l’état drépanocytaire pourrait atténuer et ralentir ce phénomène de vieillissement vasculaire précoce, ceci en dépit d’une accélération paradoxale de la VOP par l’hypotension artérielle chronique. Enfin, le mode de vie chasseurs-pêcheurs-cueilleurs protègerait l’aorte des pygmées traditionnels contre le risque de vieillissement prématuré, ceci indépendamment de la pression artérielle moyenne et de l’âge chronologique.<p> / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Page generated in 0.0597 seconds