Lipoprotein (a): Structure, Pathophysiology and Clinical Implications

The chemical structure of lipoprotein (a) is similar to that of LDL, from which it differs due to the presence of apolipoprotein (a) bound to apo B100 via one disulfide bridge. Lipoprotein (a) is synthesized in the liver and its plasma concentration, which can be determined by use of monoclonal antibody-based methods, ranges from < 1 mg to > 1,000 mg/dL. Lipoprotein (a) levels over 20-30 mg/dL are associated with a two-fold risk of developing coronary artery disease. Usually, black subjects have higher lipoprotein (a) levels that, differently from Caucasians and Orientals, are not related to coronary artery disease. However, the risk of black subjects must be considered. Sex and age have little influence on lipoprotein (a) levels. Lipoprotein (a) homology with plasminogen might lead to interference with the fibrinolytic cascade, accounting for an atherogenic mechanism of that lipoprotein. Nevertheless, direct deposition of lipoprotein (a) on arterial wall is also a possible mechanism, lipoprotein (a) being more prone to oxidation than LDL. Most prospective studies have confirmed lipoprotein (a) as a predisposing factor to atherosclerosis. Statin treatment does not lower lipoprotein (a) levels, differently from niacin and ezetimibe, which tend to reduce lipoprotein (a), although confirmation of ezetimibe effects is pending. The reduction in lipoprotein (a) concentrations has not been demonstrated to reduce the risk for coronary artery disease. Whenever higher lipoprotein (a) concentrations are found, and in the absence of more effective and well-tolerated drugs, a more strict and vigorous control of the other coronary artery disease risk factors should be sought

Gully erosion, land uses, water and soil dynamics: a case study of Nazareno (Minas Gerais, Brazil)

Gully erosion is a critical issue worldwide. To correctly associate environmental data (as climate, soil, vegetation cover, topography, etc.) and soil erosion susceptibility with land uses remains a challenge in land management. We examine the returning soil removal of a reclaimed gully in Nazareno city, Minas Gerais’ state (Brazil), comparing field assessment with laboratory experiments using two types of soil (well-developed soil and granite-gneiss saprolite). Both of them showed that macroscopic behavior of soils is connected with microscopic characteristics. Well-developed soil is more erosion resistant than granite-gneiss saprolite, but the surrounding land uses do not respect these differences. These analyses have enabled to explain why this and other gullies in the municipality are apparently stabilized, but soil losses remain occurring. It is demonstrated that urban and rural expansion played the major role in triggering gullies and soil losses

Gully erosion, land uses, water and soil dynamics: a case study of Nazareno (Minas Gerais, Brazil)

Gully erosion is a critical issue worldwide. To correctly associate environmental data (as climate, soil, vegetation cover, topography, etc.) and soil erosion susceptibility with land uses remains a challenge in land management. We examine the returning soil removal of a reclaimed gully in Nazareno city, Minas Gerais’ state (Brazil), comparing field assessment with laboratory experiments using two types of soil (well-developed soil and granite-gneiss saprolite). Both of them showed that macroscopic behavior of soils is connected with microscopic characteristics. Well-developed soil is more erosion resistant than granite-gneiss saprolite, but the surrounding land uses do not respect these differences. These analyses have enabled to explain why this and other gullies in the municipality are apparently stabilized, but soil losses remain occurring. It is demonstrated that urban and rural expansion played the major role in triggering gullies and soil losses.Erosión es un problema crítico en todo el mundo. Este documento evalúa las interacciones de los usos del suelo con la dinámica macroscópica y propiedades microscópicas del suelo frente a la susceptibilidad su erosión. Examinamos la reativación de una cárcava recuperada en la ciudad de Nazareno (Brasil), comparando la evaluación de campo con experimentos de laboratorio utilizando dos tipos de suelo (suelo bien desenvuelto y granito-gneiss saprolito). Ambos demostraron que el comportamiento macroscópico de los suelos esta relacionado con las características microscópicas. Suelo bien desenvuelto es más resistente a la erosión que granito-gneiss saprolito, pero los usos de la tierra de los alrededores no respeta estas diferencias. Estos análisis han permitido explicar por qué este y otras cárcavas del municipio aparentemente se estabilizaron, pero las pierdas de suelo siguen ocurriendo. Se ha demostrado que la expansión urbana y rural desempeñó un papel importante en el desencadenamiento de estas erosiones y pierdas de suelo

Gully erosion, land uses, water and soil dynamics: A case study of Nazareno (Minas Gerais, Brazil)

Gully erosion is a critical issue worldwide. To correctly understand the association that the environmental data (such as climate, vegetation cover, etc.) has with soil erosion susceptibility and land uses remains a challenge in land management. This paper evaluates land use interactions with macroscopic dynamics and microscopic soil properties in terms of soil’s susceptibility to erosion. We examine the reactivation of a stabilized gully in Nazareno (Brazil) by comparing field assessments with laboratory experiments, using two types of soil (well-developed soil and granite-gneiss saprolite). Both of these showed that the macroscopic behavior of soils is connected with microscopic characteristics. Well-developed soil is more erosion resistant than granite-gneiss saprolite, but the surrounding land uses do not respect these differences. These analyses enable us to explain why this and other gullies in the municipality are apparently stabilized, but soil loss continues to occur. This paper demonstrates that urban and rural expansion played a major role in triggering gully and soil losses.Erosión es un problema crítico en todo el mundo. Este documento evalúa las interacciones de los usos del suelo con la dinámica macroscópica y propiedades microscópicas del suelo frente a la susceptibilidad su erosión. Examinamos la reativación de una cárcava recuperada en la ciudad de Nazareno (Brasil), comparando la evaluación de campo con experimentos de laboratorio utilizando dos tipos de suelo (suelo bien desenvuelto y granito-gneiss saprolito). Ambos demostraron que el comportamiento macroscópico de los suelos esta relacionado con las características microscópicas. Suelo bien desenvuelto es más resistente a la erosión que granito-gneiss saprolito, pero los usos de la tierra de los alrededores no respeta estas diferencias. Estos análisis han permitido explicar por qué este y otras cárcavas del municipio aparentemente se estabilizaron, pero las pierdas de suelo siguen ocurriendo. Se ha demostrado que la expansión urbana y rural desempeñó un papel importante en el desencadenamiento de estas erosiones y pierdas de suelo

Diabetes subdiagnosticado e necrose miocárdica: preditores de hiperglicemia no infarto do miocárdio

FUNDAMENTO: Hiperglicemia na fase aguda do infarto do miocárdio é importante fator prognóstico. Entretanto, sua fisiopatologia não está completamente elucidada. OBJETIVO: Analisar simultaneamente correlação entre hiperglicemia e marcadores bioquímicos relacionados ao estresse,metabolismo glicídico e lipídico, coagulação, inflamação e necrose miocárdica. MÉTODOS: Oitenta pacientes com infarto agudo do miocárdio foram incluídos prospectivamente. Os parâmetros analisados foram: glicose, hormônios do estresse (cortisol e norepinefrina), fatores do metabolismo glicídico [hemoglobina glicada (HbA1c), insulina], lipoproteínas (colesterol total, LDL, HDL, LDL eletronegativa minimamente modificada e adiponectina), glicerídeos (triglicérides, VLDL e ácido graxo), fatores da coagulação (fator VII, fibrinogênio,inibidor do ativador do plasminogênio-1), inflamação (proteína C reativa ultrassensível) e necrose miocárdica (CK-MB e troponina). Variáveis contínuas foram convertidas em graus de pertinência por intermédio de lógica fuzzy. RESULTADOS: Houve correlação significativa entre hiperglicemia e metabolismo glicídico (p < 0,001), lipoproteínas (p = 0,03) e fatores de necrose (p = 0,03). Na análise multivariada, somente metabolismo glicídico (OR = 4,3; IC = 2,1-68,9 e p < 0,001) e necrose miocárdica (OR = 22,5; IC = 2-253 e p = 0,012) mantiveram correlação independente e significativa.Para análise da influência da história de diabetes mellitus , modelo de regressão, incluindo somente pacientes sem diabetes mellitus foi desenvolvido, e os resultados não alteraram. Finalmente, no modelo ajustado para idade, sexo e variáveis clínicas(história de diabetes mellitus, hipertensão arterial e dislipidemia), três variáveis mantiveram associação significativa e independente com hiperglicemia: metabolismo glicídico (OR = 24,1; IC = 4,8-122,1 e p < 0,001) necrose miocárdica (OR = 21,9; IC = 1,3-360,9 e p = 0,03) e história de DM (OR = 27, IC = 3,7-195,7 e p = 0,001). CONCLUSÃO: Marcadores do metabolismo glicídico e necrose miocárdica foram os melhores preditores de hiperglicemia em pacientes com infarto agudo do miocárdio

The Interplay of Sirtuin-1, LDL-Cholesterol, and HDL Function: A Randomized Controlled Trial Comparing the Effects of Energy Restriction and Atorvastatin on Women with Premature Coronary Artery Disease

Introduction: HDL function has gained prominence in the literature as there is a greater predictive capacity for risk in early coronary artery disease when compared to the traditional parameters. However, it is unclear how dietary energy restriction and atorvastatin influence HDL function. Methods: A randomized controlled trial with 39 women with early CAD divided into three groups (n = 13): energy restriction (30% of VET), atorvastatin (80 mg), and control. Analyses of traditional biochemical markers (lipid and glucose profile), circulating Sirt-1, and HDL function (lipid composition, lipid transfer, and antioxidant capacity). Results: Participants&rsquo; mean age was 50.5 &plusmn; 3.8 years. Energy restriction increased Sirt-1 by 63.6 pg/mL (95%CI: 1.5&ndash;125.7; p = 0.045) and reduced BMI by 0.8 kg/m2 (95%CI: &minus;1.349&ndash;&minus;0.273; p = 0.004) in a manner independent of other cardiometabolic factors. Atorvastatin reduced LDL-c by 40.0 mg/dL (95%CI: &minus;69.910&ndash;&minus;10.1; p = 0.010). Increased Sirt-1 and reduced BMI were independently associated with reduced phospholipid composition of HDL (respectively, &beta; = &minus;0.071; CI95%:&minus;0.136&ndash;&minus;0.006; p = 0.033; &beta; = 7.486; CI95%:0.350&ndash;14.622; p = 0.040). Reduction in BMI was associated with lower HDL-free cholesterol (&beta; = 0.818; CI95%:0.044&ndash;1.593; p = 0.039). LDL-c reduction by statins was associated with reduced maximal lipid peroxide production rate of HDL (&beta; = 0.002; CI95%:0.000&ndash;0.003; p = 0.022) and total conjugated diene generation (&beta; = 0.001; CI95%:0.000&ndash;0.001; p = 0.029). Conclusion: This study showed that energy restriction and atorvastatin administration were associated with changes in lipid profile, serum Sirt-1 concentrations, and HDL function