Key exploited species as surrogates for coastal conservation in an oceanic archipelago: insights from topshells and limpets from Madeira (NE Atlantic Ocean)

As lapas e os caramujos estão entre os herbívoros mais bem adaptados ao intertidal do Atlântico Nordeste. Estas espécies-chave fornecem serviços ecossistémicos valiosos, desempenhando um papel fundamental no equilíbrio ecológico do intertidal e têm um elevado valor económico, estando sujeitas a altos níveis de exploração e representando uma das atividades económicas mais rentáveis na pesca de pequena escala no arquipélago da Madeira. Esta dissertação visa preencher as lacunas existentes na história de vida e dinâmica populacional destas espécies, e aferir os efeitos da regulamentação da apanha nos mananciais explorados. A abordagem conservacionista implícita ao longo desta tese pretende promover: (i) a regulamentação adequada da apanha de caramujos (Phorcus sauciatus) e (ii) a avaliação dos efeitos da regulamentação da apanha de lapas nas populações exploradas (Patella aspera, Patella candei). Atualmente, os mananciais de lapas e caramujos são explorados perto do rendimento máximo sustentável, e a monitorização e fiscalização são fundamentais para evitar a futura sobre-exploração. A regulamentação da apanha de lapas produziu um efeito positivo nas espécies de lapas exploradas, com um aumento no tamanho, na proporção de indivíduos reprodutores, no tamanho de maturação e num maior equilíbrio na proporção de sexos. A apanha de caramujos não está regulamentada e com o atual nível de exploração ocorrem alterações na estrutura de tamanhos, abundância e potencial reprodutivo das populações exploradas, pelo que urge implementar a regulamentação da apanha desta espécie, por forma a mitigar os efeitos negativos desta atividade. O efeito da proximidade das populações humanas e acessibilidade costeira na estrutura de tamanhos e abundância de gastrópodes explorados mostrou que a proporção de reprodutores e a abundância eram geralmente menores em áreas mais próximas das populações humanas e em áreas mais acessíveis. Os efeitos das Áreas Marinhas Protegidas na proteção das populações de lapas resultaram num aumento diferencial do tamanho, da maturidade sexual e da captura por unidade de esforço de acordo com o grau de proteção. O esclarecimento e envolvimento das comunidades locais, reguladores, decisores políticos e partes interessadas, baseados em informação e educação, são cruciais para uma gestão eficaz e sustentável destes gastrópodes marinhos e ecossistemas a médio e longo prazo.Limpets and topshells are among the most successful intertidal grazers in the North-eastern Atlantic. These keystone species play a pivotal role in structuring rocky shores communities, and provoding valuable ecosystem services. Than have an important economic value, being subject to high levels of exploitation and representing one of the most profitable economic activities in small-scale fisheries in the archipelago of Madeira. This thesis aims to fill the gaps on the life-traits and population dynamics of these species, and assess the effects of harvesting regulations on the exploited stocks. A focus on conservation is implicit throughout this thesis since it addresses the promotion of: (i) proper regulation of the unregulated harvesting of topshells (Phorcus sauciatus) and (ii) provide additional information on the effects of harvesting regulations on limpets (Patella aspera, Patella candei). Currently, limpets and topshells stocks are being exploited near the maximum sustainable yield and monitoring and enforcement must be accomplished to avoid future overexploitation. Conservation measures prompted a positive effect on both exploited limpet species with an increase in length, reproductive individuals, size-at-first maturity and a more balanced sex-ratio after harvesting regulations. The harvesting of topshells is not regulated and with the current level of exploitation there are changes in the size structure, abundance and reproductive potential of the exploited populations, so it is imperative to implement the harvesting regulations for this species, in order to mitigate the negative effects of harvesting. The effect of proximity to human settlements and coastal accessibility on the size-structure and abundance of exploited gastropods showed that the mean-size, proportion of reproductive individuals and abundance were generally smaller in areas closer to human settlements and in more accessible areas. The effects of protection from the Marine Protected Areas on limpet populations resulted in a differential increase on size, size-at-first maturity and catch-per-unit-effort according to the degree of protection. The understanding and commitment of local communities, regulators, policymakers and stakeholders, based on information and education are crucial to the effective management and to ensure the sustainability of these marine gastropods and ecosystems at medium and long term

Effects of a self-management arthritis programme with an added exercise component for osteoarthritic knee : randomized controlled trial

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Mathematical Modeling and Simulation of Ventricular Activation Sequences: Implications for Cardiac Resynchronization Therapy

Next to clinical and experimental research, mathematical modeling plays a crucial role in medicine. Biomedical research takes place on many different levels, from molecules to the whole organism. Due to the complexity of biological systems, the interactions between components are often difficult or impossible to understand without the help of mathematical models. Mathematical models of cardiac electrophysiology have made a tremendous progress since the first numerical ECG simulations in the 1960s. This paper briefly reviews the development of this field and discusses some example cases where models have helped us forward, emphasizing applications that are relevant for the study of heart failure and cardiac resynchronization therapy

Hypertension and heart failure: a dysfunction of systole, diastole or both?

The pathological myocardial hypertrophy associated with hypertension contains the seed for further maladaptive development. Increased myocardial oxygen consumption, impaired epicardial coronary perfusion, ventricular fibrosis and remodelling, abnormalities in long-axis function and torsion, cause, to a varying degree, a mixture of systolic and diastolic abnormalities. In addition, chronotropic incompetence and peripheral factors such as lack of vasodilator reserve and reduced arterial compliance further affect cardiac output particularly on exercise. Many of these factors are common to hypertensive heart failure with a normal ejection fraction as well as systolic heart failure. There is increasing evidence that these apparently separate phenotypes are part of a spectrum of heart failure differing only in the degree of ventricular remodelling and volume changes. Furthermore, dichotomizing heart failure into systolic and diastolic clinical entities has led to a paucity of clinical trials of therapies for heart failure with a normal ejection fraction. Therapies aimed at reversing myocardial fibrosis, and targets outside the heart such as enhancing vasodilator reserve and improving chronotropic incompetence deserve further study and may improve the exercise capacity of hypertensive heart failure patients. Hypertension heart disease with heart failure is simply not a dysfunction of systole and diastole. Other peripheral factors including heart rate and vasodilator response with exercise may deserve equal attention in an attempt to develop more effective treatments for this disorder

Left ventricular long axis function in diastolic heart failure is reduced in both diastole and systole: Time for a redefinition?

Objective: To test the hypothesis that, when measured in the long axis, left ventricular systolic function is abnormal in patients with diastolic heart failure. Design: A case-control study. Setting: University teaching hospital (tertiary referral centre). Patients: 68 patients with heart failure, 29 with a left ventricular ejection fraction (LVEF) of > 0.45 and diastolic dysfunction (diastolic heart failure), 39 with an LVEF of ≤ 0.45 (systolic heart failure), and 105 normal subjects, including 33 age matched controls. Methods: LVEF was measured by cross sectional Simpson's method, and mitral annular amplitudes and velocities by M mode and tissue Doppler echocardiography, respectively, along with mitral Doppler inflow velocities. Results were compared between the three groups. Main outcome measures: Peak systolic mitral annular velocity and amplitude between the different groups. Results: The mitral annular peak mean velocity and amplitude in systole were lower in the patients with diastolic heart failure (mean (SEM), 4.8 (0.2) cm/s) than in the age matched normal controls (6.1 (0.14) cm/s), but higher than those with systolic heart failure (2.8 (0.13) cm/s) (all p < 0.001). Similar changes were seen the mitral annular amplitude during systole. Peak early diastolic velocity and amplitude were also significantly reduced in the group with diastolic heart failure. Left ventricular hypertrophy was evident in over 95% patients in both diastolic and systolic heart failure groups, with a comparable left ventricular mass index. Conclusions: In patients with diastolic heart failure and evidence of left ventricular hypertrophy, there is systolic left ventricular impairment as measured by myocardial Doppler imaging of the longitudinal axis. Thus subtle abnormalities of systolic function are present in patients with heart failure and a normal left ventricular ejection fraction, and there appears to be a continuum of systolic function between those with truly normal, mildly impaired (labelled diastolic heart failure), and obviously abnormal left ventricular systolic function. Isolated diastolic dysfunction is uncommon.link_to_subscribed_fulltex

What a drag

Aims: The purpose of this study was to assess the feasibility of measuring left atrial dysfunction with tissue Doppler imaging derived strain rate and to explore its role in predicting the maintenance of sinus rhythm after cardioversion for atrial fibrillation. Methods and results: Strain rate (SR) and tissue Doppler imaging (TDI) were performed with offline analysis of the basal left atrial wall (LA). SR detected a systolic (Ssr) and early diastolic (Esr) deformation induced by ventricular motion. LA dimensions and volume were measured. Left atrial appendage emptying (LAA_EV) and filling (LAA_FV) velocities were also obtained by transesophageal echocardiography. 27 healthy age-matched controls and 42 patients with AF before cardioversion were studied. Patients were grouped into (1): those who remained in sinus rhythm (group S, n = 12) and (2) those who either failed cardioversion or reverted to AF within 4 weeks (group F, n = 30). LA dimensions were significantly larger and atrial Esr was significantly lower in group F than group S (all p < 0.01). LAA_EV and LAA_FV were not different between groups S and F. Multivariate regression analysis showed that a lower Esr and larger transverse LA diameter (LADtr) were independent predictors of failure of cardioversion (HR, 95% CI: 0.36, 0.14-0.88 and 2.85, 1.33-6.10, respectively). Esr combined with LADtr improved the sensitivity and specificity for predicting successful cardioversion. Conclusions: SR can be measured in the basal LA wall in atrial fibrillation and the magnitude of the early diastolic SR could predict the success of cardioversion and the likelihood of maintenance of sinus rhythm. © 2006 Elsevier Ireland Ltd. All rights reserved.link_to_subscribed_fulltex

Predictive value of 18F-FDG PET-CT in primary breast cancer patients receiving neoadjvuant chemotherapy

Conference Theme: Primary Therapy of Early Breast Cance

Strain rate imaging differentiates transmural from non-transmural myocardial infarction: a validation study using delayed-enhancement magntic resonance imaging

OBJECTIVES: The aim of this study was to determine if strain rate imaging (SRI) correlates with the transmural extent of myocardial infarction (MI) measured by contrast-enhanced magnetic resonance imaging (Ce-MRI). BACKGROUND: Identification of the transmural extent of myocardial necrosis and degree of non-viability after acute MI is clinically important. METHODS: Tissue Doppler echocardiography with SRI and Ce-MRI were performed in 47 consecutive patients with a first acute MI between days 2 and 6 and compared to 60 age-matched healthy volunteers. Peak myocardial velocities and peak myocardial deformation strain rates were measured. Location and size of the infarct zone was confirmed by Ce-MRI using the delayed enhancement technique with a 16-segment model. RESULTS: Contrast-enhanced MRI identified transmural infarction in 21 patients, non-transmural infarction in 15 (mean transmurality of infarct 72.3 ± 10.6%), and another 11 patients with subendocardial infarction (-0.59 s -1 detected a transmural infarction with high sensitivity (90.9%) and high specificity (96.4%), and -0.98 s -1 >SRs >-1.26 s -1 distinguished subendocardial infarction from normal myocardium with a sensitivity of 81.3% and a specificity of 83.3%. CONCLUSIONS: Peak myocardial deformation by SRI can differentiate transmural from non-transmural MI, and it allows noninvasive determination of transmurality of the scar after MI and thereby the extent of non-viable myocardium. © 2005 by the American College of Cardiology Foundation.link_to_subscribed_fulltex