RESUMEN
AIM: This study aimed to investigate the acute effects of dietary nitrate ingestion through l-arginine supplementation or dehydrated beet consumption on endothelial function in chronic obstructive pulmonary disease (COPD) patients. The secondary outcome was to analyze arterial stiffness, plasma nitrate, and nitrate/protein concentration. METHODS: In this randomized crossover study, subjects with COPD underwent three series of supplementation: (1) l-arginine, (2) dehydrated beetroot, and (3) a placebo that appeared like the other supplements. Each intervention lasted 14 days, with a 7-day washout period between series. Participants underwent endothelial function assessment using flow-mediated dilatation (FMD), and plasma nitrate levels were measured at the end of each supplementation series. RESULTS: Seventeen subjects (twelve male) completed the study protocol. Only five subjects presented endothelial dysfunction (RHI ≤0.51) at baseline. The mean baseline characteristics included age 66.5 ± 9.4 years, BMI 27.5 ± 4.5 kg/m2, FEV1, 0.79 (0.67-1.06) L. There were no differences (p > 0.05) between the groups or from pre-to post-interventions for RHI and arterial stiffness index (AIx) values, as well as parameters of endothelium-dependent vasodilation, such as blood flow velocity (BFV), shear stress, shear rate, FMD (mm), and FMD%. There was also no differences (p > 0.05) between the groups or from pre-to post-interventions plasma nitrate levels. CONCLUSIONS: Acute dietary supplementation with nitrates, at the doses provided, did not show a significant improvement in endothelial function assessed by FMD, EndoPAT, or plasma nitrate levels in COPD. These findings suggest that a higher dose or prolonged supplementation might be required to achieve a therapeutic effect.
Asunto(s)
Beta vulgaris , Estudios Cruzados , Suplementos Dietéticos , Endotelio Vascular , Nitratos , Enfermedad Pulmonar Obstructiva Crónica , Rigidez Vascular , Humanos , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Masculino , Anciano , Femenino , Nitratos/administración & dosificación , Nitratos/sangre , Nitratos/uso terapéutico , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiopatología , Persona de Mediana Edad , Rigidez Vascular/efectos de los fármacos , Rigidez Vascular/fisiología , Arginina/administración & dosificación , Arginina/sangre , Vasodilatación/efectos de los fármacosRESUMEN
BACKGROUND: The best treatment for coronary artery disease (CAD) in patients with type 2 diabetes (DM2) and chronic kidney disease is unknown. METHODS: This retrospective study included MASS registry patients with DM2 and multivessel CAD, stratified by kidney function. Primary endpoint was combined of mortality, myocardial infarction, or additional revascularization. RESULTS: Median follow-up was 9.5 years. Primary endpoint occurrences among strata 1 and 2 were 53.4% and 40.7%, respectively (P=.020). Mortality rates were 37.4% and 24.6% in strata 1 and 2, respectively (P<.001). We observed a lower rate of major adverse cardiovascular events (MACE) (P=.027 for stratum 1 and P<.001 for stratum 2) and additional revascularization (P=.001 for stratum 1 and P<.001 for stratum 2) for those in the surgical group. In a multivariate analysis, eGFR was an independent predictor of MACE (P=.034) and mortality (P=.020). CONCLUSIONS: Among subjects with DM2 and CAD the presence of lower eGFR rate was associated with higher rates of MACE and mortality, irrespective of treatment choice. CABG was associated with lower rates of MACE in both renal function strata. eGFR was an independent predictor of MACE and mortality in a 10-year follow-up.
Asunto(s)
Enfermedad de la Arteria Coronaria/tratamiento farmacológico , Nefropatías Diabéticas/complicaciones , Anciano , Aspirina/administración & dosificación , Bloqueadores de los Canales de Calcio/administración & dosificación , Enfermedad de la Arteria Coronaria/etiología , Enfermedad de la Arteria Coronaria/mortalidad , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/fisiopatología , Nefropatías Diabéticas/fisiopatología , Femenino , Estudios de Seguimiento , Humanos , Pruebas de Función Renal , Masculino , Persona de Mediana Edad , Nitratos/administración & dosificación , Estudios Prospectivos , Estudios RetrospectivosRESUMEN
O condicionamento é uma técnica de pré-embebição de sementes em água ou em solução, por determinado tempo e temperatura, com o objetivo de ativar os processos metabólicos iniciais das sementes. Trabalho conduzido com objetivo de avaliar a influência de diferentes períodos de condicionamento fisiológico em solução de nitrato de potássio (KNO3) sobre a germinação de sementes de beterraba, cultivar Early Wonder Tall Top, para a produção de baby leafs. Experimento realizado no laboratório de sementes do Centro Universitário Integrado, Campo Mourão PR. O delineamento utilizado foi inteiramente casualizado, onde os tratamentos foram constituídos por diferentes períodos de condicionamento em solução KNO3 (0, 8, 16, 24 e 32 h) e um material híbrido cv. Cabernet para título de comparação, totalizando assim, seis tratamentos (5+1), com oito repetições de 50 sementes. As sementes foram condicionadas em folhas de papel germitest preparadas em recipientes gerbox com a solução de condicionamento em câmara germinadora e temperatura de 25 °C. As variáveis analisadas foram a Porcentagem de Germinação; Índice de Velocidade de Germinação e Velocidade de Germinação. A técnica apresentou resultados favoráveis na germinação, na velocidade de germinação e na padronização da germinação do lote. A máxima porcentagem de germinação foi observada após 16 h de condicionamento. Todos os períodos de condicionamento foram superiores em relação à testemunha híbrida, confirmando a eficácia da técnica.(AU)
Priming is a technique of pre-soaking seeds into water or solution for a certain time and temperature in order to activate the initial seeds metabolic processes. This paper was conducted with the objective of evaluating the influence of different physiological conditioning periods in potassium nitrate solution (KNO3) on the germination of beet seeds cultivar Early Wonder Tall Top for the production of baby leafs. Experiment performed in the seed laboratory of the Centro Universitário Integrado, at Campo Mourão - PR. The design was completely randomized, where the treatments were constituted by different conditioning periods in KNO3 solution (0, 8, 16, 24 and 32 h) and a hybrid material cv. Cabernet for comparison, totaling six treatments (5 + 1), with eight replicates of 50 seeds each treatment. The seeds were conditioned on two sheets of germitest paper prepared in gerbox containers with the conditioning solution in a germination chamber at 25 °C. The analyzed variables were germination percentage, index of germination speed and germination speed. The maximum germination percentage was observed after 16 h of conditioning. All the conditioning periods were superior in relation to the hybrid witness, confirming the effectiveness of the technique.(AU)
Asunto(s)
Beta vulgaris/crecimiento & desarrollo , Beta vulgaris/efectos de los fármacos , Germinación , Nitratos/administración & dosificaciónRESUMEN
O condicionamento é uma técnica de pré-embebição de sementes em água ou em solução, por determinado tempo e temperatura, com o objetivo de ativar os processos metabólicos iniciais das sementes. Trabalho conduzido com objetivo de avaliar a influência de diferentes períodos de condicionamento fisiológico em solução de nitrato de potássio (KNO3) sobre a germinação de sementes de beterraba, cultivar Early Wonder Tall Top, para a produção de baby leafs. Experimento realizado no laboratório de sementes do Centro Universitário Integrado, Campo Mourão PR. O delineamento utilizado foi inteiramente casualizado, onde os tratamentos foram constituídos por diferentes períodos de condicionamento em solução KNO3 (0, 8, 16, 24 e 32 h) e um material híbrido cv. Cabernet para título de comparação, totalizando assim, seis tratamentos (5+1), com oito repetições de 50 sementes. As sementes foram condicionadas em folhas de papel germitest preparadas em recipientes gerbox com a solução de condicionamento em câmara germinadora e temperatura de 25 °C. As variáveis analisadas foram a Porcentagem de Germinação; Índice de Velocidade de Germinação e Velocidade de Germinação. A técnica apresentou resultados favoráveis na germinação, na velocidade de germinação e na padronização da germinação do lote. A máxima porcentagem de germinação foi observada após 16 h de condicionamento. Todos os períodos de condicionamento foram superiores em relação à testemunha híbrida, confirmando a eficácia da técnica.
Priming is a technique of pre-soaking seeds into water or solution for a certain time and temperature in order to activate the initial seeds metabolic processes. This paper was conducted with the objective of evaluating the influence of different physiological conditioning periods in potassium nitrate solution (KNO3) on the germination of beet seeds cultivar Early Wonder Tall Top for the production of baby leafs. Experiment performed in the seed laboratory of the Centro Universitário Integrado, at Campo Mourão - PR. The design was completely randomized, where the treatments were constituted by different conditioning periods in KNO3 solution (0, 8, 16, 24 and 32 h) and a hybrid material cv. Cabernet for comparison, totaling six treatments (5 + 1), with eight replicates of 50 seeds each treatment. The seeds were conditioned on two sheets of germitest paper prepared in gerbox containers with the conditioning solution in a germination chamber at 25 °C. The analyzed variables were germination percentage, index of germination speed and germination speed. The maximum germination percentage was observed after 16 h of conditioning. All the conditioning periods were superior in relation to the hybrid witness, confirming the effectiveness of the technique.
Asunto(s)
Beta vulgaris/crecimiento & desarrollo , Beta vulgaris/efectos de los fármacos , Germinación , Nitratos/administración & dosificaciónRESUMEN
HIV-1 proteins and highly active antiretroviral therapy (HAART) have been associated with microvascular endothelial dysfunction. Although nitrate-rich beetroot juice (NR-BJ) consumption has been shown to improve endothelial function in clinical population, its effects in HIV-infected patients has not been addressed. We investigated the effect of a single dose of NR-BJ on muscle oxygen saturation parameters in response to a handgrip exercise in HIV-infected patients. Fifteen HIV-infected patients received NR-BJ or nitrate-depleted beetroot juice (ND-BJ) in a double-blind cross-over design. Near-IR spectroscopy was utilised to assess muscle oxygen saturation parameters during rhythmic handgrip exercise after NR-BJ or ND-BJ supplementation. A significant faster muscle oxygen desaturation rate during exercise (-7·97 (sd 5·00) v. -5·45 (3·94) %/s, P = 0·005) and muscle oxygen resaturation rate during exercise recovery (0·43 (0·24) v. 0·28 (0·24) %/s, P = 0·030) after NR-BJ ingestion was found. However, no significant difference in exercise time until fatigue was observed. Salivary nitrite and urinary nitrate concentration were analysed after NR-BJ or ND-BJ. A significant increase in salivary nitrite and urinary nitrate in NR-BJ was observed compared with ND-BJ (P < 0·05). Our findings suggest that NR-BJ consumption may acutely improve muscle oxygen saturation during exercise and exercise recovery in HIV-infected patients undergoing HAART and who are expected to present microvascular damage. Thus, future studies investigating the chronic effects of NR-BJ are warranted to delineate a better nutritional strategy based on nitrate-rich foods.
Asunto(s)
Terapia Antirretroviral Altamente Activa/efectos adversos , Beta vulgaris , Jugos de Frutas y Vegetales , Nitratos/administración & dosificación , Consumo de Oxígeno/efectos de los fármacos , Adulto , Estudios Cruzados , Suplementos Dietéticos , Método Doble Ciego , Células Endoteliales , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/fisiopatología , Infecciones por VIH/virología , VIH-1 , Fuerza de la Mano , Humanos , Masculino , Microvasos/metabolismo , Persona de Mediana Edad , Músculo Esquelético/irrigación sanguínea , Resultado del Tratamiento , Adulto JovenRESUMEN
Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach in order to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up tilt test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge in order to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective and safe in this specific age group. The aim of this article is to make a literature search in order to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up tilt test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.
El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).
Asunto(s)
Síncope Vasovagal/diagnóstico , Síncope/diagnóstico , Pruebas de Mesa Inclinada/métodos , Niño , Humanos , Isoproterenol/administración & dosificación , Isoproterenol/efectos adversos , Nitratos/administración & dosificación , Nitratos/efectos adversos , Pruebas de Mesa Inclinada/efectos adversosRESUMEN
Precise coordination of cell expansion and cell proliferation underlies growth in multicellular organisms. In addition to endogenous developmental programs, external environmental signals are integrated to modulate organ growth in plants. Nitrate is a nitrogen nutrient that can act as a potent signal to modulate shoot growth, yet the molecular mechanisms involved are largely unexplored in Arabidopsis thaliana or other plant species. Herein, we show that nitrate regulates vegetative growth by modulating cell size and endoreplication. We identified the LGO gene, a CDK inhibitor, as a key cell cycle regulatory factor influencing ploidy and cell-size depending on external nitrate. Nitrate induces LGO gene expression as early as 3 days after germination in epidermal and mesophyll cell layers, which undergo endoreplication to increment DNA content and cell size. Our results support a dual role for LGO on endoreplication and cell expansion. Surprisingly, although endoreplication and cell size are greatly reduced in lgo-2 mutant plants and increased in LGO-OX plants, cotyledon size remains unchanged relative to wild type and is set by the amount of nitrate. In lgo-2 mutant plants where cells are unable to endoreplicate fully, cotyledon organ size is achieved through cell division. We conclude nitrate generally controls cotyledon and leaf size by increasing ploidy levels and cell expansion but that cell division can substitute for endoreplication without affecting final organ size or growth in plants.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efectos de los fármacos , Arabidopsis/crecimiento & desarrollo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Nitratos/farmacología , Proteínas Nucleares/metabolismo , Tallos de la Planta/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Reducción Gradual de Medicamentos , Regulación del Desarrollo de la Expresión Génica , Nitratos/administración & dosificación , Proteínas Nucleares/genética , Tallos de la Planta/efectos de los fármacos , Transducción de SeñalRESUMEN
BACKGROUND: Malignant pleural effusion is one of the most important complications of metastatic cancer, and recurrent pleural effusions do not only have an impact on survival but also cause a huge repercussion on a patient's quality of life. OBJECTIVES: The main objective was to describe quality of life status before and after pleurodesis in patients with malignant pleural effusion. Secondary, we aimed to find predictors of quality of life improvement in such a population. METHODS: Retrospective analysis of a database collected prospectively. We included patients who underwent pleurodesis from June 2004 to July 2014. Quality of life was evaluated through the WHOQOL-BREF questionnaire and applied before and 30 days after pleurodesis. We used a paired t test and the Wilcoxon rank-sum to compare pre-/post-pleurodesis results, Kaplan-Meier curves for survival analysis, and multiple linear regressions to find predictors of quality of life improvement. RESULTS: 183 patients were included (145 were women). Mean age was 58.3 ± 12.3 years, the most numerous primary tumor was breast cancer. Median survival time was 9 months. Dyspnea was the most prevalent symptom. Baseline results showed that patients had low quality of life scores. After pleurodesis, there was a significant improvement in respiratory symptoms, physical domain, and general health. Linear regression showed an improvement in physical domain with the sclerosing agent nitrate (p = 0.005). Male gender (p = 0.002) and a higher lymphocyte count (p = 0.01) were inversely associated with improvement in physical domain. CONCLUSIONS: Pleurodesis improved symptoms and quality of life in patients with malignant pleural effusion. Gender, lymphocyte count, and sclerosing agent might interfere with quality of life improvement.
Asunto(s)
Derrame Pleural Maligno/terapia , Pleurodesia/métodos , Pleurodesia/psicología , Calidad de Vida , Anciano , Brasil , Bases de Datos Factuales , Femenino , Humanos , Yodo/administración & dosificación , Estimación de Kaplan-Meier , Modelos Lineales , Masculino , Persona de Mediana Edad , Análisis Multivariante , Nitratos/administración & dosificación , Derrame Pleural Maligno/diagnóstico por imagen , Derrame Pleural Maligno/mortalidad , Pronóstico , Estudios Retrospectivos , Medición de Riesgo , Índice de Severidad de la Enfermedad , Tasa de Supervivencia , Talco/administración & dosificación , Resultado del TratamientoRESUMEN
Nitrate (NO3 -) supplementation is associated with exercise performance, oxygen uptake, blood flow, and blood pressure improvement, and it can act as an antioxidant agent. This study evaluated the effects of sodium nitrate supplementation on oxidative stress markers and blood pressure responses after aerobic exercise performance in physically active males. Fourteen subjects aged 22 ± 3 years and with a BMI of 23 ± 1 kg/m2 were submitted to four exercise tests in intervals of 5 days. Nitrate supplementation (NO session) and placebo supplementation (PL session) were acute (AC) and over a period of 5 days (FD) in random order with a crossover design. Saliva was collected at basal (0'); 60 min after supplementation (60'); immediately after exercise (90'); and 15, 30, and 60 min after the test (105', 120', and 150'). The NO session had higher concentrations (P < 0.05) of salivary nitrite in both AC and FD treatments when compared with the PL session. There was a reduction in systolic blood pressure (SBP) only after FD in the NO session. Furthermore, uric acid and total antioxidant capacity (FRAP) salivary concentrations increased, while SOD activity and TBARS levels decreased after FD but not after AC in the NO session. The results suggest that nitrate supplemented over a period of 5 days reduced SBP and indirectly acted as an antioxidant in healthy nonsedentary young men.
Asunto(s)
Antioxidantes/administración & dosificación , Presión Sanguínea/efectos de los fármacos , Suplementos Dietéticos , Nitratos/administración & dosificación , Adulto , Estudios Cruzados , Ejercicio Físico/fisiología , Prueba de Esfuerzo , Humanos , Masculino , Nitritos/metabolismo , Estrés Oxidativo/efectos de los fármacos , Saliva/metabolismoRESUMEN
This study aimed to verify the effect of beetroot juice on post-exercise ambulatory blood pressure (BP) in obese individuals. Fourteen non-hypertensive obese males were randomly assigned to three experimental sessions: 1) Beetroot juice with exercise (BJE, 200ml with ≈ 800mg nitrate and 40 minutes of moderate-intensity aerobic exercise at an intensity of 50% of the heart rate reserve), 2) fruit soda with exercise (FSE, 200ml of a low-nitrate drink and the same exercise session) and 3) control (CON, 200ml of water, an insignificant nitrate drink without exercise). The concentration of total nitrites and nitrates in plasma (NOx) after the drinks and the 24-hour ambulatory BP were evaluated. A two-way (condition vs. time) ANOVA for repeated measures, with a Bonferroni post hoc was used to analyze variables. The plasma NOx concentration increased significantly after ingestion of beetroot juice (from 9.9 ± 8.4 µM to 47.0 ± 16.9 µM, p < 0.001) and remained elevated until 1 hour post-intervention (54.7 ± 10.1 µM, p < 0.001), while it did not change in FSE and CON groups. The BJE session decreased ambulatory systolic BP in 5.3 mmHg (IC95%, -10.1 to -0.6, p = 0.025) in the period of 1-6 h after the BJE session compared to the CON session and reduction of 3.8 mmHg (IC95%, -7.5 to -0.007, p = 0.05) compared to the FSE session. No significant changes were observed for ambulatory diastolic BP (p > 0.05). BJE enhanced the reduction of systolic ambulatory BP up to 6 hours following a moderate-intensity aerobic exercise in obese individuals with an elevated cardiovascular risk profile.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , Suplementos Dietéticos , Ejercicio Físico/fisiología , Nitratos/administración & dosificación , Obesidad/fisiopatología , Adulto , Antropometría , Beta vulgaris/química , Enfermedades Cardiovasculares , Estudios Cruzados , Humanos , Masculino , Nitratos/sangre , Nitritos/sangre , Obesidad/sangre , Estudios Prospectivos , Factores de Riesgo , Adulto JovenRESUMEN
Nitrate (NO3 -) is an ergogenic nutritional supplement that is widely used to improve physical performance. However, the effectiveness of NO3 - supplementation has not been systematically investigated in individuals with different physical fitness levels. The present study analysed whether different fitness levels (non-athletes v. athletes or classification of performance levels), duration of the test used to measure performance (short v. long duration) and the test protocol (time trials v. open-ended tests v. graded-exercise tests) influence the effects of NO3 - supplementation on performance. This systematic review and meta-analysis was conducted and reported according to the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A systematic search of electronic databases, including PubMed, Web of Science, SPORTDiscus and ProQuest, was performed in August 2017. On the basis of the search and inclusion criteria, fifty-four and fifty-three placebo-controlled studies evaluating the effects of NO3 - supplementation on performance in humans were included in the systematic review and meta-analysis, respectively. NO3 - supplementation was ergogenic in non-athletes (mean effect size (ES) 0·25; 95 % CI 0·11, 0·38), particularly in evaluations of performance using long-duration open-ended tests (ES 0·47; 95 % CI 0·23, 0·71). In contrast, NO3 - supplementation did not enhance the performance of athletes (ES 0·04; 95 % CI -0·05, 0·15). After objectively classifying the participants into different performance levels, the frequency of trials showing ergogenic effects in individuals classified at lower levels was higher than that in individuals classified at higher levels. Thus, the present study indicates that dietary NO3 - supplementation improves physical performance in non-athletes, particularly during long-duration open-ended tests.
Asunto(s)
Suplementos Dietéticos , Prueba de Esfuerzo , Nitratos/administración & dosificación , Rendimiento Físico Funcional , Atletas , Rendimiento Atlético , Ejercicio Físico , Humanos , Resistencia Física , Medición de RiesgoRESUMEN
INTRODUCTION: Endothelial function at high altitude has been measured only in populations that are genetically adapted to chronic hypoxia. The objective of this study was to evaluate endothelial dysfunction (ED) in a nongenetically adapted high-altitude population of the Andes mountains, in Huancayo, Peru (3,250 meters above sea level). METHODS: Participants included 61 patients: 28 cases and 33 controls. The cases were subjects with hypertension, diabetes mellitus, obesity, or a history of stroke or coronary artery disease. Flow-mediated vasodilation (FMD) of the brachial artery was measured in the supine position, at noon, after 5 minutes of resting. The brachial artery was identified above the elbow. Its basal diameter was measured during diastole, and FMD was tested after 5 minutes of forearm ischemia. Intima-media complex in the right carotid artery was also determined. An increase in the artery's baseline diameter <10% indicated a positive test. Endothelium-independent vasodilation was evaluated with sublingual nitrate administration. The intima-media complex in the right carotid artery was also measured. RESULTS: 100% of diabetics had ED; ED was also found in 68.8% of obese individuals, 55% of hypertensive patients, and 46.5% of controls. Age, height, body mass index, and waist diameter were higher in the cases as compared with the controls. A total of 57.9% (n=11) of the cases and 45.2% (n=19) of the controls presented ED. Patients without ED had a mean increase in brachial artery diameter of 23.16%, while in those with ED it was only 3.84%. Individuals with diabetes or hypertension had a greater thickness of the carotid artery intima media layer (1.092 versus 0.664 cm) (p=0.037). A positive test for ED was associated with a greater basal diameter of the brachial artery (4.66±0.62 versus 4.23±0.59 cm) (p=0.02). A total of 7 patients presented paradoxical response, developing posthyperemia vasoconstriction. DISCUSSION: The proportion of ED was high among controls and among patients with risk factors. Controls showed better FMD profiles than subjects studied in Tibet and the Himalayas.
Asunto(s)
Altitud , Arteria Braquial/fisiopatología , Enfermedades Cardiovasculares/fisiopatología , Diabetes Mellitus/fisiopatología , Endotelio Vascular/fisiopatología , Obesidad/fisiopatología , Vasoconstricción , Vasodilatación , Aclimatación , Administración Sublingual , Anciano , Arteria Braquial/efectos de los fármacos , Enfermedades Cardiovasculares/diagnóstico por imagen , Enfermedades Cardiovasculares/epidemiología , Grosor Intima-Media Carotídeo , Estudios de Casos y Controles , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiología , Endotelio Vascular/efectos de los fármacos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nitratos/administración & dosificación , Obesidad/diagnóstico , Obesidad/epidemiología , Perú/epidemiología , Flujo Sanguíneo Regional , Factores de Riesgo , Vasodilatación/efectos de los fármacos , Vasodilatadores/administración & dosificaciónRESUMEN
Both recovery time of post-exercise muscle oxygenation and muscle strength decline with aging. Although beetroot consumption has been shown to improve muscle oxygenation and exercise performance in adults, these effects in the elderly has not been addressed. The aim of the present study was to evaluate the effect of a beetroot-based gel (BG) on muscle O2 saturation, blood volume (tHb) and handgrip strength in the elderly in response to handgrip exercise. In a randomized crossover double-blind design, twelve older subjects consumed BG (100 g of beetroot-based gel containing ~ 12 mmol nitrate) or PLA (100 g of nitrate-depleted gel nitrate-depleted). The subjects performed a rhythmic handgrip exercise which consisted of a one 1-min set at 30% of the maximal voluntary contraction (MVC) of each subject, followed by a 1 min recovery. The muscle oxygenation parameters and tHb were continuously monitored by using near-infrared spectroscopy. MVC was evaluated at baseline, immediately after exercise, and 30 min afterwards. The muscle O2 resaturation rate during exercise recovery was greater in the BG when compared to PLA condition (1.43 ± 0.77 vs 1.02 ± 0.48%.s-1; P < 0.05). Significant increase was observed in tHb during exercise recovery (10.25 ± 5.47 vs 6.72 ± 4.55 µM; P < 0.05) and significant reduction of handgrip strength decline was observed 30 min after exercise in BG (- 0.24 ± 0.18 vs-0.39 ± 0.20 N; P < 0.05). In summary, a single dose of a beetroot-based gel speeds up muscle O2 resaturation, increases blood volume and improves recovery of handgrip strength after handgrip exercise in older adults.
Asunto(s)
Volumen Sanguíneo , Dieta , Fuerza Muscular , Músculo Esquelético/metabolismo , Nitratos/administración & dosificación , Oxígeno/metabolismo , Anciano , Estudios Cruzados , Método Doble Ciego , Femenino , Fuerza de la Mano , Humanos , Masculino , Nitratos/orinaRESUMEN
A alface (Lactuca sativa L.) possui grande importância na alimentação humana, como fonte de vitaminas e sais minerais, além de possuir baixo valor calórico. Apesar do cultivo hidropônico estar em expansão no Brasil e ser bastante vantajoso, não há uma legislação específica dos nutrientes a serem utilizados para produção dessas hortaliças, levando ao risco da veiculação de contaminantes como o nitrato por meio da solução nutritiva. O objetivo do trabalho foi avaliar o teor de nitrato e as características físico-químicas de amostras de alface de duas espécies, cultivadas no sistema hidropônico e convencional.As amostras de alface foram coletadas semanalmente, em triplicata,no comércio local, por cinco semanas consecutivas, sendo analisados dois tipos de alface (crespa e/ou americana) produzidos pelo sistema convencional e hidropônico. Observou-se maior variação nos teores de cinzas e nitrato entre os sistemas de cultivo (hidropônico e convencional)e nos teores de vitamina C entre os tipos de alface (crespa e americana).Os maiores teores de nitrato foram encontrados nas amostras de alface hidropônica, com destaque para a cultivar Americana. Os teores de nitrato encontrados não excederam o limite máximo permitido pela legislação internacional.(AU)
Lettuce (Lactuca sativa L.) has great importance in human food, asa source of vitamins and minerals, besides having low caloric value. Although the hydroponic cultivation is in expansion in Brazil and to be quite advantageous, there is no specific legislation of the nutrients to be used for the production of these vegetables, leading to the risk of contaminants such as nitrate through the nutrient solution. The objective of this work was to evaluate the nitrate content and the physicochemical characteristics of lettuce samples of two species grown in the hydroponic and conventional systems. The lettuce samples were collected weekly in triplicate, in local commerce for five consecutive weeks, and two types of lettuce (crisp and / or American) produced by the conventional and hydroponic system were analyzed. It was observed a greater variation in the levels of ashes and nitrate between the cultivation systems (hydroponic and conventional) and the vitamin C contents between lettuce types (crisp and American). The highest levels of nitrate were found in the hydroponic lettuce samples, with emphasis on the cultivar Americana. The nitrate levels found did not exceed the maximum limit allowed by international legislation.(AU)
Asunto(s)
Humanos , Lactuca/química , Hidroponía , Fenómenos Químicos , Nitratos/administración & dosificación , Muestras de Alimentos , Valor Nutritivo , Ácido AscórbicoRESUMEN
A alface (Lactuca sativa L.) possui grande importância na alimentação humana, como fonte de vitaminas e sais minerais, além de possuir baixo valor calórico. Apesar do cultivo hidropônico estar em expansão no Brasil e ser bastante vantajoso, não há uma legislação específica dos nutrientes a serem utilizados para produção dessas hortaliças, levando ao risco da veiculação de contaminantes como o nitrato por meio da solução nutritiva. O objetivo do trabalho foi avaliar o teor de nitrato e as características físico-químicas de amostras de alface de duas espécies, cultivadas no sistema hidropônico e convencional. As amostras de alface foram coletadas semanalmente, em triplicata, no comércio local, por cinco semanas consecutivas, sendo analisados dois tipos de alface (crespa e/ou americana) produzidos pelo sistema convencional e hidropônico. Observou- se maior variação nos teores de cinzas e nitrato entre os sistemas de cultivo (hidropônico e convencional) e nos teores de vitamina C entre os tipos de alface (crespa e americana). Os maiores teores de nitrato foram encontrados nas amostras de alface hidropônica, com destaque para a cultivar Americana. Os teores de nitrato encontrados não excederam o limite máximo permitido pela legislação internacional.(AU)
Asunto(s)
Humanos , Lactuca/química , Hidroponía , Nitratos/administración & dosificación , Ácido Ascórbico , Muestras de Alimentos , Valor NutritivoRESUMEN
While nitrate supplementation influences oxygen uptake (VÌO2) response to exercise, this effect may be intensity dependent. The purpose of this study was to investigate the effect of acute nitrate supplementation on VÌO2 response during different exercise intensity domains in humans. Eleven men ingested 10 mg·kg-1 body mass (8.76 ± 1.35 mmol) of sodium nitrate or sodium chloride (placebo) 2.5 h before cycling at moderate (90% of gas exchange threshold; GET), heavy (GET + 40% of the difference between GET and peak oxygen uptake (VÌO2peak), Δ 40) or severe (GET + 80% of the difference between GET and VÌO2peak, Δ 80) exercise intensities. Volunteers performed exercise for 10 min (moderate), 15 min (heavy) or until exhaustion (severe). Acute nitrate supplementation had no effect on any VÌO2 response parameters during moderate and severe exercise intensities. However, the VÌO2 slow amplitude (nitrate: 0.93 ± 0.36 L·min-1 vs. placebo: 1.13 ± 0.59 L·min-1, p = 0.04) and VÌO2 slow gain (nitrate: 5.81 ± 2.37 mL·min-1·W-1 vs. placebo: 7.09 ± 3.67 mL·min-1·W-1, p = 0.04) were significantly lower in nitrate than in placebo during the heavy exercise intensity. There was no effect of nitrate on plasma lactate during any exercise intensity (p > 0.05). Time to exhaustion during the severe exercise intensity was also not affected by nitrate (p > 0.05). In conclusion, acute nitrate supplementation reduced the slow component of VÌO2 only when performing heavy-intensity exercise, which might indicate an intensity-dependent effect of nitrate on VÌO2 response.
Asunto(s)
Ejercicio Físico , Nitratos/administración & dosificación , Consumo de Oxígeno/efectos de los fármacos , Adulto , Índice de Masa Corporal , Estudios Cruzados , Suplementos Dietéticos , Método Doble Ciego , Humanos , Ácido Láctico/sangre , Masculino , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/fisiología , Cloruro de Sodio/administración & dosificación , Encuestas y Cuestionarios , Adulto JovenRESUMEN
Nitrite and nitrate restore deficient endogenous nitric oxide (NO) production as they are converted back to NO, and therefore complement the classic enzymatic NO synthesis. Circulating nitrate and nitrite must cross membrane barriers to produce their effects and increased nitrate concentrations may attenuate the nitrite influx into cells, decreasing NO generation from nitrite. Moreover, xanthine oxidoreductase (XOR) mediates NO formation from nitrite and nitrate. However, no study has examined whether nitrate attenuates XOR-mediated NO generation from nitrite. We hypothesized that nitrate attenuates the vascular and blood pressure responses to nitrite either by interfering with nitrite influx into vascular tissue, or by competing with nitrite for XOR, thus inhibiting XOR-mediated NO generation. We used two independent vascular function assays in rats (aortic ring preparations and isolated mesenteric arterial bed perfusion) to examine the effects of sodium nitrate on the concentration-dependent responses to sodium nitrite. Both assays showed that nitrate attenuated the vascular responses to nitrite. Conversely, the aortic responses to the NO donor DETANONOate were not affected by sodium nitrate. Further confirming these results, we found that nitrate attenuated the acute blood pressure lowering effects of increasing doses of nitrite infused intravenously in freely moving rats. The possibility that nitrate could compete with nitrite and decrease nitrite influx into cells was tested by measuring the accumulation of nitrogen-15-labeled nitrite (15N-nitrite) by aortic rings using ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS). Nitrate exerted no effect on aortic accumulation of 15N-nitrite. Next, we used chemiluminescence-based NO detection to examine whether nitrate attenuates XOR-mediated nitrite reductase activity. Nitrate significantly shifted the Michaelis Menten saturation curve to the right, with a 3-fold increase in the Michaelis constant. Together, our results show that nitrate inhibits XOR-mediated NO production from nitrite, and this mechanism may explain how nitrate attenuates the vascular and blood pressure responses to nitrite.
Asunto(s)
Nitratos/metabolismo , Nitrito Reductasas/metabolismo , Nitrito de Sodio/metabolismo , Xantina Deshidrogenasa/metabolismo , Animales , Presión Sanguínea/efectos de los fármacos , Masculino , Modelos Biológicos , Nitratos/administración & dosificación , Óxido Nítrico/metabolismo , Compuestos Nitrosos/farmacología , Ratas , Nitrito de Sodio/administración & dosificaciónRESUMEN
PURPOSE OF REVIEW: Ergogenic supplements in sport events are widely used by popular and competitive athletes to enhance performance and reduce oxygen cost. Beetroot juice and nitrate salts have been increasingly used for the past 5-6 years. The present review discusses the scientific background, the efficiency and potential adverse effects of excessive nitrate supplementation. RECENT FINDINGS: There is clear evidence that nitrate from different food ingredients (such as beetroot juice and other vegetables) is converted into nitrite and possibly into nitric oxide, which may promote vasodilation, angiogenesis and mitochondrial biogenesis. The high affinity of nitric oxide towards different enzyme pathways inhibits excessive mitochondrial respiration and, therefore, tissue oxygen consumption. In addition, L-arginine supplements are proposed to stimulate nitric oxide synthesis in the endothelium. On the basis of these biochemical properties, nitrate supplementation has been suggested to athletes to enhance exercise performance. SUMMARY: The recent publications in human individuals based on L-arginine, beetroot juice or nitrate supplementation revealed either a minor positive effect or no systematic effect on exercise performance, especially in trained athletes. Of note, the sugar content of whole beetroot juice might induce a slightly more pronounced effect. Although reasonable intake of nitrate salts (up to 1âg/day) has no detrimental effect on kidney function, the risk and benefit of higher nitrate intake needs to be evaluated to define the optimal range of supplementation.
Asunto(s)
Rendimiento Atlético , Suplementos Dietéticos , Ejercicio Físico , Nitratos/farmacología , Arginina/farmacología , Beta vulgaris/química , Humanos , Nitratos/administración & dosificación , Nitratos/metabolismoRESUMEN
The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE) was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0-4) during bleaching and up to 48 h after each session. The primary outcome of absolute risk of tooth sensitivity was compared using the Fisher's exact test (α = 0.05). The intensity of tooth sensitivity and the efficacy of in-office bleaching were also statistically evaluated. No significant differences in absolute risk and intensity of tooth sensitivity were detected between the groups (p = 1.0 and p = 0.53, respectively). BE was also found to be similar between the groups (p = 0.67). Although the use of a nano-calcium phosphate paste associated with fluoride and potassium nitrate did not influence the whitening outcome, but it also did not reduce bleaching-induced tooth sensitivity.
Asunto(s)
Fosfatos de Calcio/administración & dosificación , Desensibilizantes Dentinarios/administración & dosificación , Sensibilidad de la Dentina/inducido químicamente , Peróxido de Hidrógeno/administración & dosificación , Nitratos/administración & dosificación , Compuestos de Potasio/administración & dosificación , Blanqueadores Dentales/administración & dosificación , Blanqueamiento de Dientes/efectos adversos , Adulto , Fosfatos de Calcio/efectos adversos , Método Doble Ciego , Femenino , Humanos , Peróxido de Hidrógeno/efectos adversos , Masculino , Nitratos/efectos adversos , Compuestos de Potasio/efectos adversos , Blanqueamiento de Dientes/métodos , Blanqueadores Dentales/efectos adversos , Decoloración de Dientes/tratamiento farmacológico , Adulto JovenRESUMEN
OBJECTIVES: To evaluate the efficacy of experimental proposals of desensitizing agents during tooth bleaching. METHODS: 140 participants without tooth sensitivity (TS) received 16% carbamide peroxide (14 days-04 h each) (T1) or 35% hydrogen peroxide (single session-45 min) (T2). Participants used concomitantly (10 per group): desensitizing dentifrices (D1-experimental bioactive glass-ceramic; D2-commercial potassium nitrate; D3-commercial calcium and sodium phosphosilicate) in-home, daily and, desensitizing pastes (D4-experimental bioactive glass-ceramic; D5-experimental Bioglass type 45S5; D6-commercial calcium phosphate), in-office, immediately after the treatment and more 4 times. Participants in the control group did not use any desensitizing agent. We assessed TS with Visual Analogue Scale. Assessment point 1 was immediately after the first participant's exposure to the treatments; and points 2, 3, 4, and 5 were every 72 h along the period of the study. Two-way ANOVA (considering time and desensitizing as factors) and post-hoc Tukey test (α=0.05) analyzed the data. RESULTS: In the control group treated with 35% hydrogen peroxide, TS increased significantly on assessment points 1 and 2. The participants who used a 5% potassium nitrate dentifrice and in-office experimental pastes did not experience TS because of the 35% in-office bleaching treatment. CONCLUSIONS: TS caused by 35% hydrogen peroxide in-office tooth bleaching was controlled by experimental products prepared as pastes D4-experimental bioactive glass-ceramic and D5-experimental Bioglass type 45S5, but not by D1-experimental dentifrice containing bioactive glass-ceramic. CLINICAL SIGNIFICANCE: There is no a gold standard protocol for TS caused by tooth bleaching. The study of novel desensitizing agents that can obliterate the dentinal tubules in a faster-acting and long-lasting way may help meet this clinical need.