Nueva ecuación para la estimación de la natriuresis diaria a partir de parámetros en plasma y orina aislada en población chilena / A new equation to estimate daily natriuresis from parameters in plasma and spot urine sample in the Chilean population

Background: Excessive sodium intake is associated with increased cardiovascular morbidity and mortality. Daily sodium intake is usually inferred from sodium excretion in a 24-hour urine collection, which is cumbersome and prone to errors. Different formulas have attempted to estimate 24-hour urinary sodium from a spot urine sample. Unfortunately, their concordances are insufficient and have not been tested in our population. Aim: To develop an equation to predict 24-hour urine sodium from parameters in plasma and spot urine samples. To validate the equation and compare it with other formulas in Chilean population. Material and Methods: Analysis of 24-hour urine collections, plasma sample and spot urine sample from 174 adult outpatients (81% females) with an estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73m2. These were collected between 2015 and 2019 using standardized methods and educating patients about the correct method to collect 24 h urine samples. In all these patients, creatinine and electrolytes were measured in plasma and urine. A new equation was developed using a multiple linear regression model. Results: Twenty-four-hour urine sodium excretion was significantly correlated with age, weight, height, eGFR, plasma osmolarity, urine electrolytes and parameters obtained from spot urine sample, among others. The new equation had a linear correlation with 24-hour natriuresis of 0.91 and the concordance was 0.9. The predictive capacity of the new equation was better than the existing formulas. Conclusions: We developed a formula to accurately predict daily natriuresis in the Chilean population.

Efeito agudo da drenagem linfática manual sobre a natriurese e lipólise de mulheres jovens / Acute effect of manual lymphatic drainage on natriuresis and lipolysis in young women

Fundamentos: A importância da validação científica de técnicas coadjuvantes a diversos tratamentos de saúde é inquestionável. Desta forma, a influência da drenagem linfática manual (DLM) na natriurese e na lipólise sob interação de anticoncepcional oral precisa ser investigada. Objetivos: Avaliar o efeito agudo da DLM sobre a natriurese e lipólise de mulheres jovens usuárias ou não de anticoncepcional oral. Método: Participaram 29 mulheres não usuárias de anticoncepcional oral e 29 usuárias, autodeclaradas saudáveis, sedentárias e eutróficas. As análises foram realizadas em dois dias distintos, Controle (C), sem intervenção terapêutica e DLM. Nos dias C e DLM coletamos 4 amostras de urina com intervalos de 60 min. Seguimos o método de Leduc, abdomem e membros inferiores, durante 45 min. Analisamos o fluxo urinário e excreção urinária e sódio, glicerol e peptideo natriurético atrial. A normalidade dos dados foi analisada pelo teste Shapiro-Wilk. Os dados que não obedeceram à normalidade foram apresentados em mediana e intervalo interquartil (25%-75%), enquanto os que obedeceram foram apresentados em média ± erro padrão. O teste de Mann-Whitney foi usado para dados não pareados e Wilcoxon para dados pareados. Dados com normalidade foram avaliados pelo teste t-Student não pareado. O nível de significância estatística adotado foi de 5%. Resultados: O efeito agudo de uma sessão de DLM promove aumento da natriurese em mulheres não usuárias de anticoncepcional oral, por outro lado, em usuárias induz aumento na liberação de glicerol e de ANP

Background: The importance of scientific validation of supporting techniques to various treatments is unquestionable. In this context, the influence of manual lymphatic drainage (MLD) on natriuresis and lipolysis and its interaction with oral contraceptives still need to be investigated. Objectives: To evaluate the acute effect of MLD on natriuresis and lipolysis in young women using or not oral contraceptives. Methods: Twenty-nine non-users of oral contraceptives and 29 oral contraceptive users, self-reported healthy, sedentary, normal weight women were enrolled. Analyses were conducted on two different days ­ control (C), without therapeutic intervention and MLD day. Four urine samples were collected at 60-minute intervals. MLD was performed in lower limbs and abdomen for 45 min following the Leduc method. Urinary flow rat e and urinary sodium, glycerol and atrial natriuretic peptide excretion were analyzed. Data normality was tested by the Shapiro-Wilk test. Data without normal distribution were expressed as median and interquartile range (25%-75%), while normally distributed data were expressed as mean ± standard error. Mann-Whitney test was used for unpaired data and Wilcoxon test for paired data. Data with normal distribution were evaluated by the unpaired t-Student test. Statistical significance was set at 5%. Results: One MLD session had an acute effect on both groups, increasing natriuresis in non-users of oral contraceptives and glycerol and atrial natriuretic peptide excretion in oral contraceptive users. Conclusion: Oral contraceptives influence the effect of MLD on natriuresis

Patrones de excreción urinaria de Sodio en población adulta en muestras de orina espontánea / Urinary sodium excretion patterns in adult population in spot urine samples

Introducción: El presente estudio describe los patrones de natriuresis según las características clínicas y sociodemográficas en una población adulta de Asunción. Métodos: Estudio transversal tipo encuesta y toma de muestra de orina a personas que acudieron al Mercado de Abasto y al Policlínico Municipal durante los meses de junio-setiembre del 2014. Se estimó natriuria en muestras de orina espontánea a primera hora de la mañana y en ayunas. Se incluyeron sujetos de 18 a 65 años. Se compararon las medianas de los valores de natriuria en mmol/L, utilizándose el test U de Mann-Whitney para comparar las variables de dos categorías y Kruskal-Wallis para las que tienen más de dos categorías. Resultados: Se aplicó la encuesta y se tomó muestra de orina a 463 personas. El 69,5% (322) eran mujeres. La media de edad fue 50,5 años (DE: 14,2). El 26,6% (123) negó antecedentes patológicos. La mediana de natriuria global fue 97,5 mmol/L (RIC: 59,3­139,3). Los niveles de natriuria no presentaron diferencias por sexo. Las personas menores de 30 años, con bajo consumo de verduras y mayor consumo de frituras presentaron valores de natriuria altos y estadísticamente significativos. El grupo de sujetos sanos mostró mayor excreción de sodio que los que refirieron diabetes o hipertensión arterial. Conclusiones: La mayor excreción de sodio en orina observada se presenta en personas jóvenes, sin antecedentes patológicos y, al mismo tiempo son los que también presentan los peores hábitos alimenticios. Estos resultados muestran la necesidad de intervención en el ámbito de la salud pública a fin de prevenir la patología cardiovascular y renal del futuro.

Introduction: The present study describes natriuresis patterns according to clinical and sociodemographic characteristics in adult population of Asuncion. Methods: Cross-sectional study of convenience sampling to people who attended the Mercado de Abasto and the Municipal Polyclinic during June to September 2014. People from 18 to 65 years old were included. Sodium was estimated from urine samples of spot urine taken in the morning and fasting. Median values of natriuresis in mmol/L were compared using the test Mann-Whitney and Kruskal-Wallis. Results: 463 people participated. 69.5% (322) were women. The mean age was 50.5 years (SD 14.2). 26.6% (123) denied pathological medical history. The median overall natriuresis was 97.5 mmol/L (IQR: 59.3-139.3). Natriuresis levels did not differ by sex. High values with statistically significant were presented in people under 30 years old, with low consumption of vegetables and increased consumption of fried food. The group of healthy subjects showed increased sodium excretion than those who reported diabetes or high blood pressure. Conclusions: The increased natriuresis occurs in young people without having pathological medical history and also having the worst eating habits. Public health policies must focus at this level to prevent future cardiovascular and renal disease it is at this level where public health must intervene to prevent future cardiovascular and renal disease.

Fator natriurético atrial: ele é o responsável pela hiponatremia e natriurese em neurocirurgia? / Atrial natriuretic factor: is it responsible for hyponatremia and natriuresis in neurosurgery?

RESUMO Objetivo: Avaliar a presença de hiponatremia e natriurese, bem como suas associações com o fator natriurético atrial em pacientes de neurocirurgia. Métodos: Foram incluídos 30 pacientes submetidos à ressecção de tumor intracraniano e à clipagem de aneurisma cerebral. Os níveis plasmáticos e urinários de fator natriurético atrial foram medidos durante os períodos pré e pós-operatório. Resultados: Hiponatremia esteve presente em 63,33% dos pacientes, particularmente no primeiro dia pós-operatório. Observou-se natriurese em 93,33% dos pacientes, principalmente no segundo dia pós-operatório. Os níveis plasmáticos de fator natriurético atrial estavam aumentados em 92,60% dos pacientes em pelo menos um dos dias pós-operatórios, mas não houve associação estatisticamente significante entre fator natriurético atrial e sódio plasmático, e entre fator natriurético atrial e sódio urinário. Conclusão: Após neurocirurgia, na maior parte dos pacientes, estiveram presentes hiponatremia e natriurese; contudo, o fator natriurético atrial não pôde ser considerado diretamente responsável por tais alterações nos pacientes neurocirúrgicos. Provavelmente, há o envolvimento de outros fatores natriuréticos.

ABSTRACT Objective: To evaluate the presence of hyponatremia and natriuresis and their association with atrial natriuretic factor in neurosurgery patients. Methods: The study included 30 patients who had been submitted to intracranial tumor resection and cerebral aneurism clipping. Both plasma and urinary sodium and plasma atrial natriuretic factor were measured during the preoperative and postoperative time periods. Results: Hyponatremia was present in 63.33% of the patients, particularly on the first postoperative day. Natriuresis was present in 93.33% of the patients, particularly on the second postoperative day. Plasma atrial natriuretic factor was increased in 92.60% of the patients in at least one of the postoperative days; however, there was no statistically significant association between the atrial natriuretic factor and plasma sodium and between the atrial natriuretic factor and urinary sodium. Conclusion: Hyponatremia and natriuresis were present in most patients after neurosurgery; however, the atrial natriuretic factor cannot be considered to be directly responsible for these alterations in neurosurgery patients. Other natriuretic factors are likely to be involved.

Investigación de la ingesta de sal mediante natriuresis en escolares de 6 a 13 años de La Pampa / RESEARCH IN SALT INTAKE BY NATRIURESIS IN CHILDREN AGED 6 TO 13 THE PROVINCE OF LA PAMPA

Introducción: en la provincia de La Pampa prevalece una alta ingesta de carnes y fiambres. Existe promoción en adultos para disminuir la ingesta de sal, no focalizada en niños. Objetivos: investigar en escolares de la comunidad agrícolaganadera la ingesta de sal mediante la natriuresis y determinar riesgo de hipertensión arterial. Materiales y métodos: estudio piloto, exploratorio, descriptivo en 67 niños/niñas de 6-13 años, de escuela de jornada completa, sin restricción dietética. Se determinó frecuencia de ingesta de fiambres, peso, talla e IMC, perímetro de cintura mínima (cm) y un control de presión arterial (PA). Se describen los resultados según sexo, edad y percentiles (Pc) de talla (Task Force, 2004). Se determinó natriuresis (matutina y vespertina) e ingesta de sal (método de Tanaka, et al.). Se informaron los resultados a la familia y se educó sobre los factores de riesgo cardiovasculares. Resultados: el 96% consumía frecuentemente fiambres, el 14,66% tenía un Pc de PA anormal. Las niñas mayores de 9 años tuvieron mayor peso (p:0,01) e IMC que los varones (p:0,02). Los varones menores de 9 años tenían mayores niveles de natriuresis matutina que las niñas (p:0,04). La ingesta de sal/24 h de las niñas menores de 9 años fue de 2,48±1,99 g y 3,19±0,36 g en las mayores (p:0,09), siendo de 1,82±0,56 y 3,27±1,03 g respectivamente en los niños (p:0,01). Conclusiones: hallamos un consumo elevado de sal en la población estudiada, aumentando significativamente en varones a partir de los 9 años poniéndolos en riesgo de hipertensión arterial. Se debe efectuar un programa de alimentación saludable especialmente a partir de esta edad para el control de peso en las niñas y de la ingesta de sal en los niños, informando a los médicos responsables para que efectúen el control de la presión arterial en particular.

El efecto anti-hipertensivo de angiotensina-(1-9) es mediado por aumento temprano de la diuresis y natriuresis / Cardiac arrest associated to intramural hematoma of the anterior descending coronary artery

Introducción: Angiotensina (Ang)-(1-9) posee propiedades anti-hipertensivas y efecto protector a nivel cardiovascular en ratas hipertensas. Sin embargo, se desconoce si estos efectos están asociados a un mecanismo de desbalance de sodio a nivel renal. Objetivo: Determinar si el efecto anti-hipertensivo de Ang-(1-9) está asociado a un mecanismo diurético-na-triurético. Método: Ratas macho Sprague Dawley (200 ± 10g) fueron aleatorizadas para recibir Ang II (400 ng/kgmin) vía bomba osmótica. Como control se utilizaron ratas con operación sham (n=18). Después de 2 semanas desde la instalación de bomba, las ratas Sham e hipertensas fueron randomizadas para recibir vehículo (n=10), Ang-(1-9) (602 ng/kg/min, n=17) o una co-administración de Ang-(1-9) y A779 (100 ng kg-1min-1, n=7 bloqueador del receptor MAS) por 2 semanas. Resultados: Se determinó la presión arterial sistólica (PAS), masa ventricular relativa (MVR), área y perímetro de los cardiomiocitos (AC y PC) y la fracción volumétrica de colágeno total (FVCT). Para evaluar la diuresis y natriuresis se utilizaron ratas normotensas que fueron randomizadas para recibir vehículo (n=8) o Ang-(1-9) (600 ngKg-1min-1, n=8) por 6 días. Se observó un incremento significativo(p<0.05) de PAS (33%), MVR (17%), AC (64%), PC (20%), FVCT (46%). La administración crónica de Ang-(1-9) disminuyó PAS (20%), MVR (13 %), AC (35%), PC (20%) y FVCT (20%). Estos efectos no fueron mediados por el receptor MAS. Al comparar las ratas normotensas tratadas con vehículo o Ang-(1-9), se observó un aumento significativo de la diuresis y natriuresis en los días 2 y 3 en los animales con infusión de Ang-(1-9). Conclusión: Ang-(1-9) reduce la hipertensión y el remodelamiento cardíaco en ratas hipertensas. En animales normotensos se demostró que el tratamiento con Ang-(1-9)-induce diuresis y natriuresis. Este es el primer reporte que señala que el efecto de Ang-(1-9) está asociado a una regulación del sodio a nivel renal.

Background: Angiotensin-(1-9) has anti-hypertensive properties and protective cardiovascular effect in hypertensive rats. However, it is unknown whether its effects are related to a kidney mechanism to balance sodium. Aim: To determine if the anti-hypertensive effect of Ang-(1-9) is associated to a diuretic-natriuretic mechanism. Method: Sprague Dawley male rats (200±10 grs) were randomized to receive Angiotensin II by osmotic pump (400 ng/kg/min). Sham operated rats were utilized as control (n=18). Two weeks after pump setting, Sham rats with hypertension were randomized to receive placebo (n=10), Ang-(1-9)(602 ng/kg/min, n=17) or Ang-(1-9) plus A779 (Ang-(1-7) Receptor Mas blocker, 100ng/kg-1min-1, n=7) co-administration for two weeks. Arterial systolic pressure (PAS), ventricular relative mass (MVR), cardiomyocytes area and perimeter (AC and PC) and total collagen volume fraction (FVCT) were measured. Normotensive rats were utilized to evaluate diuresis and natriuresis which were randomized to receive placebo (n=8) or Ang-(1-9) (600ng/kg-1/min-1, n=8) for six days. Results: It was observed a significant rise (p<0.05) of PAS (33%), MVR (17%), AC (64%), PC (26%), FVCT (46%) was observed. Chronic administration of Ang-(1-9) reduced PAS (20%), MVR (13%), AC (35%), PC (20%) and FCVT (20%). All those effects were not mediated by Mas receptor. A significant raise was observed of diuresis and natriuresis at the second and third day of treatment in rats receiving Ang-(1-9) in comparison with normotensive rats treated with placebo. Conclusion: Ang-(1-9) reduces hypertension and cardiac remodeling in hypertensive rats. Ang-(1-9) induces natriuresis and diuresis in normotensive rats. This is the first report showing that Ang-(1-9) is associated to sodium balance in the kidney.

Papel da dipeptidil peptidase IV na fisiopatologia da insuficiência cardíaca / Role of dipeptidyl peptidase IV in the pathophysiology of heart failure

Introdução/Objetivo: Este estudo teve como objetivo testar a hipótese de que a atividade e/ou expressão da dipeptidil peptidase IV (DPPIV), uma enzima que inativa peptídeos com ações cardioreno protetoras, como o peptídeo-1 semelhante ao glucagon (GLP-1) e o peptídeo natriurético cerebral (BNP), estaria associada a um pior prognóstico na insuficiência cardíaca (HF). Métodos: Injúria do miocárdio foi realizada através da ablação do ventrículo esquerdo (VE) por radiofrequência em ratos Wistar machos (200-250 g). Os ratos foram divididos em três grupos: Sham, HF e HF + inibidor de DPPIV (sitagliptina 200mg/kg/b.i.d). Seis semanas após a cirurgia, os animais foram alojados individualmente em gaiolas metabólicas durante 3 dias para avaliação da função renal. Atividade e expressão da DPPIV no plasma e coração foram medidas por espectrofotometria e por immunoblotting, respectivamente. Para a avaliação da função cardíaca um cateter de pressão-volume foi posicionado dentro da cavidade do VE. A análise histológica foi realizada para os parâmetros morfométricos. A atividade da DPPIV no plasma também foi medida em pacientes com HF (n = 190). Resultados: A atividade DPPIV e sua abundância estavam aumentadas em animais com HF em comparação com Sham. Além disso, a atividade de DPPIV no plasma se correlacionou positivamente com o volume diastólico final (R = 0,517; p < 0,001) e o peso do pulmão/peso corporal (R = 0,492; p < 0,01). Uma correlação negativa entre a atividade DPPIV plasmática e a fração de ejeção também foi observada (R = 0,602; p < 0,001). Curiosamente, os animais HF também exibiram um aumento da expressão/atividade de DPPIV no tecido cardíaco, especialmente em células endoteliais. Seis semanas de tratamento com o inibidor de DPPIV sitagliptina atenuou a disfunção cardíaca, fibrose intersticial, congestão pulmonar e infiltração de macrófagos. O tratamento com sitagliptina também elevou os níveis plasmáticos de GLP-1 ativo, e aumentou a ativação de vias de...

Aim: The present study aimed to test the hypothesis that the activity and/or expression of dipeptidyl peptidase IV (DPPIV), an enzyme that inactivates cardiorenal protective peptides including glucagon-like peptide-1 (GLP-1) and brain natriuretic peptide (BNP), would be associated with poorer outcomes in heart failure (HF). Methods: Experimental HF was induced in male Wistar rats (200-250 g) by left ventricular (LV) myocardial injury after radiofrequency catheter ablation. Rats were divided in three groups: Sham, HF and HF+DPPIV inhibitor (sitagliptin 200mg/kg/b.i.d). Six weeks after surgery, animals were individually housed in metabolic cages during 3 days for assessment of renal function. Plasma and heart DPPIV activity/expression were measured spectrophotometrically and by immunoblotting respectively. For evaluation of cardiac function a pressure-volume catheter was positioned into the LV cavity. Histological analysis was performed for morphometric parameters. Plasma DPPIV activity was also measured in patients (n = 190) with heart failure. Results: Plasma DPPIV activity and abundance were increased in animals with HF compared to Sham. Additionally, plasma DPPIV activity positively correlated with ventricular end diastolic volume (R² =0.517; p < 0.001) and lung/body weight (R² =0.492; p < 0.01). A negative correlation between plasma DPPIV activity and ejection fraction was also observed (R² =0.602; p < 0.001). Interestingly, HF animals also exhibited an increase of expression and activity of DPPIV in heart tissue, especially in endothelial cells. Six-week treatment with the DPPIV inhibitor sitagliptin attenuated cardiac dysfunction, mitigated cardiac hypertrophy, interstitial fibrosis, lung congestion and macrophage infiltration. Sitagliptin also raised the plasma levels of active GLP-1, increased activation of cardioprotective signaling pathways including PKA, and Akt; and reduced the levels of apoptosis and pro-inflammatory biomarkers compared...

Natriuresis y hemodinámica glomerular en un incomprendido sistema renina angiotensina aldosterona / Nutriuresis and Glomerular Hemodynamics in misunderstood Renin-angiotensin-aldosterone system

La respuesta natriur‚tica y la hemodin mica glomerular dependen de diversos sistemas de regulaci¢n intrarrenal; sin embargo, la mayor¡a de ellos posee alg£n grado de dependecia del sistema renina angiotensina. La distribuci¢n tisular y el efecto hemodin mico de este sistema son de vital importancia para el entendimiento de la regulaci¢n natriur‚tica y del filtrado glomerular en diversas enfermedades que se caracterizan por desregulaci¢n del equilibrio del sodio o del filtrado glomerular, tales como el s¡ndrome nefr¢tico, la falla renal aguda y cr¢nica e hipertensi¢n arterial.

Natriuretic response and glomerular hemodynamics depend on various intrarenal regulation systems; however, most of them possess some degree of dependence on the renin-angiotensin system. Tissue distribution and hemodynamic effects of this system are of vital importance for understandinf of the natriuretic and glomerular filtration regulation in the context of different diseases characterized by dysregulation of sodium balance or glomerular filtration rate, such as nephrotic syndrome, acute and chronic renal failure and hypertension.

Efecto diurético agudo de los extractos etanólico y acuoso de Ceratopteris pteridoides (Hook) en ratas normales / Acute diuretic effect of ethanolic and aqueous extracts of Ceratopteris pteridoides (Hook) in normal rats

Introducción. Ceratopteris pteridoides es un helecho semiacuático de la familia Parkeriacea, ampliamente utilizado en la medicina popular colombiana como diurético y colelitiásico, sobre el cual no existen reportes científicos que avalen su uso popular como diurético. Objetivo. Evaluar el efecto diurético agudo en dosis única y dosis repetidas a corto plazo, de los extractos etanólico y acuoso de C. pteridoides en un modelo in vivo . Materiales y métodos. El extracto etanólico total fue obtenido por maceración de la planta entera de C. pteridoides con etanol y el extracto acuoso fue obtenido por decocción a 60 °C por 15 minutos. Ambos extractos se sometieron a análisis fitoquímico preliminar y estudio histológico posterior a la administración de los extractos durante ocho días consecutivos (1.000 mg/kg). El efecto diurético se evaluó en ratas Wistar, tratadas con los extractos (500 mg/kg), en forma aguda y en dosis repetidas a corto plazo, cuantificando la eliminación de agua y la excreción renal de sodio y potasio por espectrofotometría de absorción atómica y, de cloruros, por titulación mercurimétrica. Resultados. En el modelo agudo, ambos extractos mostraron un significativo efecto diurético y de excreción renal de sodio y potasio en comparación con el control, mientras que con la administración en dosis repetidas a corto plazo mostraron efecto diurético sin eliminación de electrolitos. El estudio histopatológico no sugirió efectos tóxicos hepáticos o renales. Conclusión. Los resultados demuestran la actividad diurética de C. pteridoides y sustentan el uso popular dado a esta planta como diurético en la costa norte colombiana. Se requieren estudios posteriores que permitan aislar e identificar los compuestos responsables de la actividad y los mecanismos de acción involucrados.

Introduction. Ceratopteris pteridoides is a semiaquatic fern of the Parkeriacea family, widely used in the Colombian folk medicine as a diuretic and cholelithiasic, of which there are no scientific reports that validate its popular use. Objective. To evaluate the acute and short-term repeated-dose diuretic effect of the ethanolic and aqueous extracts of C. pteridoides in an in vivo model. Materials and methods. The total ethanolic extract was obtained by maceration of the whole plant of C. pteridoides with ethanol and the aqueous extract by decoction at 60°C for 15 minutes. Both extracts were evaluated in preliminary phytochemical analysis and histological studies after the administration of the extracts for 8 consecutive days (1000 mg/Kg). The diuretic effect was evaluated using Wistar rats treated with the extracts (500 mg/Kg), using an acute and a short-term repeated-dose model, and quantifying water elimination, sodium and potassium excretion by atomic absorption spectrophotometry, and chloride excretion by mercurimetric titration. Results. In the acute model both extracts showed significant diuretic, natriuretic, and kaliuretic effect compared to the control group. Whereas, a short-term repeated-dose administration showed a diuretic effect without elimination of electrolytes. The histopathologic study did not suggest a toxic effect in liver or kidney. Conclusion. The results represent evidence of the diuretic activity of C. pteridoides and give support the popular use given to this plant in the north coast of Colombia. Further studies are required to isolate and identify the compounds responsible for the activity and the mechanism of action involved.

Obesidad y excreción urinaria de sodio en niños y adolescentes / Obesity and urinary sodium excretion in children and adolescents

Background: Qbesity is a disease characterized by an abnormal accumulation body fat that results in neuroen-docrine changes that alter the homeostasis of sodium, producing an increased risk of hypertension in adulthood. objective: To evaluate the effect of obesity on urinary sodium excretion in children and adolescents. subjects and Methods: 266 male and female children in the age group of 5-15 years were studied: 154 obese (OB) with > 95th percentile of BMI, and 112 normal-weight patients (C) with percentile 5-85 of BMI, from the outpatient service of the Children Hospital, Posadas, Misiones, Argentina during the years 2008 -2009. The determinations of serum sodium (Na s) and 24-hour urine (Na ur) were performed using Ion Selective Electrode. The fractional excretion of sodium (FENa percent) was calculated. results: Na ur values (mEq/kg/day) and FENa percent reported significantly lower differences in the obese group compared to controls: OB Na ur 2.23 vs C Na ur 3.40 (p < 0.0001); OB FENa percent 0.59 vs C FENa percent 0.71 (p = 0.001). Conclusion: Results obtained in the present study showed that obese children have a significantly decreased urinary sodium excretion compared to normal weight children. This difference could be caused by renal retention of this ion.

Introducción: La obesidad es una enfermedad caracterizada por el aumento de grasa corporal, que genera modificaciones neuroendocrinas involucrando alteraciones en la homeostasis del sodio, que podrían generar hipertensión arterial en la adultez. Objetivo: Evaluar el efecto de la obesidad sobre la excreción urinaria de sodio en niños y adolescentes. Pacientes y Método: Se estudiaron 266 niños de ambos sexos, entre 5 y 15 años: 154 obesos (OB) definidos como IMC percentil > 95, y 112 normopeso (C), IMC percentil 5-85, provenientes del Servicio de Consultorio Externo del Hospital de Pediatría-Posadas, Misiones, Argentina, durante los años 2008-2009. Las determinaciones de sodio en suero (Na s) y orina de 24 h (Na ur) se realizaron con electrodo ion selectivo. Se calculó la excreción fraccional de sodio (EFNa por ciento). Resultados: Los valores de Naur (mEq/ kg/día) y la EFNa por ciento significativamente menores en el grupo de obesos con respecto a los controles: Na ur QB 2,23 vs Na ur C 3,40 (p < 0,0001); EFNa por ciento OB 0,59 vs EFNa por ciento C 0,71 (p = 0,001). Conclusión: En el presente estudio los resultados mostraron que los niños y adolescentes obesos presentan una disminución significativa de la excreción urinaria de sodio respecto de los niños normopeso. Dicha diferencia podría estar generada por la retención renal de dicho ion.

Aproximación clínica al consumo de sodio / Clinical approach to sodium consumption

Introducción: el consumo de sodio se vincula directamente a las cifras de presión arterial y adicionalmente incide en el manejo de diversas enfermedades. En el año 2003, la Organización Mundial de la Salud (OMS) propone reducir el consumo poblacional de sal a menos de 5 g/día. En Uruguay no contamos con datos de mediciones directas del consumo de sodio. La medición del sodio en la orina de 24 horas es el método patrón para la determinación del consumo diario, sin embargo es un método poco usado en la prácticaclínica debido en parte a lo engorroso que resulta para el paciente. Objetivo: determinar el consumo de sodio de un grupo de voluntarios a través de la natriuria de 24 horas. Encontrar una relación entre la natriuria de una muestra de orina (spot) y la natriuria de 24 horas. Material y método: se reclutaron estudiantes de cuarto año de la carrera de Doctor en Medicina de la Universidad de la República. Se registraron antecedentes médicos, medidas antropométricas, y de presión arterial en consultorio y se recolectó la orina de 24 horas. El análisis de la relación entre el contenido de sodio en el spot y en la orina de 24 horas serealizó mediante prueba de chi cuadrado.Resultados: 33 de 45 estudiantes completaron el estudio. El consumo promedio de sodio fue de 2,9±1,1 g/día. Una natriuria en el spot mayor a 75 mEq/L se asoció a un consumo de sodiomedido por natriuria de 24 horas mayor de 100 mEq/día (p<0,005), con una sensibilidad de 95% y especificidad de 63%.

Introduction: sodium consumption is closely related to blood pressure rates and it additionally affects the handlingof different diseases. In 2003, the World Health Organization (WHO) encouraged people to reduce the consumption of sodium to under 5 g/day. In Uruguay there is no data resulting from direct measurement of sodium consumption. Measuring sodium in the 24 hour urine is the standard method to determine daily consumption, although this method is rarely used in the clinical practice due to its being bothersome for patients. Objective: to determine sodium consumption for agroup of volunteers through 24 hours natriuria. To find a relationship between spot tests of urine natriuria and 24-hour urine natriuria. Method: fourth year medical students were recruited from the School of Medicine at the University of the Republic. Medical history, anthropometric measures and blood pressure in the polyclinic were recorded and the urine was collected during 24 hours. The analysis of the relationship between the content of sodium in the spot and in the 24- hour urine was performed through square chi.Results: 33 out of 45 students completed the study. Average consumption of sodium was 2.9 2,9±1,1 g/day. Natriuria in the spot greater than 75 mEq/L was associated to sodium consumption measured by 24-hour natriuria greater than 100 mEq/día (p<0,005), with a sensitivity of95% and a specificity of 63%.

Introdução: o consumo de sódio está diretamente relacionado aos valores da pressão arterial e também tem influenciasobre o manejo de varias doenças. Em 2003, a Organização Mundial da Saúde (OMS) lançou uma proposta para reduzir o consumo de sal da população aum valor inferior a 5 g/dia. No Uruguai não estão disponíveis dados de medições diretas do consumo de sal. O método padrão para determinação de consumo diário é o exame da urina de 24 horas; no entanto não é um método muito utilizado na prática clínica por ser muito trabalhoso para o paciente. Objetivo: conhecer o consumo de sódio de um grupo de voluntários determinando a natriúria de 24 horas. Encontrar uma relação entre a natriúria de uma amostra de urina (ôspotõ) e a natriúria de 24 horas. Material e método: foram recrutados estudantes doquarto ano do curso de Medicina da Universidad de la República. Foram registrados sus antecedentes médicos,medidas antropométricas, e pressão arterial no consultório e se realizou a coleta de urina de 24 horas. A análise darelação entre o conteúdo de sódio no ôspotõ e na urina de 24 horas foi realizado utilizando a prova do X quadrado. Resultados: 33 dos 45 estudantes completaram o estudo. O consumo médio de sódio foi de 2,9±1,1 g/dia. Uma natriúria do ôspotõ superior a 75 mEq/L foi associada ao consumo de sódio medido por natriúria de 24 horas superior a 100 mEq/dia (p<0,005), com uma sensibilidadede 95% e especificidade de 63%.

Feasibility of salt reduction in processed foods in Argentina / Factibilidad de reducir el contenido de sal de los alimentos procesados en la Argentina

OBJECTIVE: To assess an intervention to reduce salt intake based on an agreement with the food industry. METHODS: Salt content was measured in bakery products through a national survey and biochemical analyses. Low-salt bread was evaluated by a panel of taste testers to determine whether a reduced salt bread could remain undetected. French bread accounts for 25 percent of the total salt intake in Argentina; hence, reducing its salt concentration from 2 percent to 1.4 percent was proposed and tested. A crossover trial was conducted to evaluate the reduction in urinary sodium and blood pressure in participants during consumption of the low-salt bread compared with ordinary bread. RESULTS: Average salt content in bread was 2 percent. This study evaluated low-salt bread containing 1.4 percent salt. This reduction remained mostly undetected by the panels of taste testers. In the crossover trial, which included 58 participants, a reduction of 25 milliequivalents in 24hour urine sodium excretion, a reduction in systolic blood pressure of 1.66 mmHg, and a reduction in diastolic blood pressure of 0.76 mmHg were found during the low-salt bread intake. CONCLUSIONS: The study showed that dietary salt reduction was feasible and well accepted in the population studied through a reduction of salt content in bread. Although the effects on urinary sodium and blood pressure were moderate, a countrywide intervention could have a greater public health impact.

OBJETIVO: Evaluar una intervención destinada a reducir el consumo de sal a partir de un convenio con la industria alimentaria. MÉTODOS: Se midió el contenido de sal de los productos de panadería por medio de una encuesta nacional y análisis bioquímicos. Un grupo de catadores evaluó el pan con bajo contenido de sal para determinar si la disminución pasaba inadvertida. Dado que el pan francés representa 25 por ciento del consumo total de sal en la Argentina, se propuso someter a prueba este tipo de pan con una disminución de la concentración de sal de 2 por ciento a 1,4 por ciento. Se realizó un estudio cruzado con el fin de evaluar si los participantes presentaban una concentración urinaria de sodio más baja y una presión arterial menor durante el período en que consumieron pan con bajo contenido de sal respecto del período en que consumieron pan común. RESULTADOS: El pan común contiene un porcentaje promedio de sal de 2 por ciento. En este estudio, el pan con bajo contenido de sal contenía 1,4 por ciento, disminución que, en general, pasó inadvertida a los catadores. En el estudio cruzado, en el que participaron 58 sujetos, la eliminación urinaria de sodio disminuyó 25 miliequivalentes en 24 horas, la presión arterial sistólica bajó 1,66 mmHg y la presión arterial diastólica bajó 0,76 mmHg durante el período en que los participantes consumieron pan con bajo contenido de sal. CONCLUSIONES: El estudio demuestra que es factible reducir la ingesta de sal alimentaria y que la población estudiada considera aceptable que el pan contenga esta menor concentración de sal. Aunque los efectos sobre la concentración urinaria de sodio y la presión arterial fueron moderados, es probable que una intervención nacional tenga repercusiones más importantes para la salud pública.

Actividad del sistema dopaminérgico renal en ratas con distinto contenido de sodio en la dieta / Activity of the renal dopaminergic system in rats

La dopamina (DA) renal modula la excreción de sodio y agua y la presión arterial por medio de receptores D1 (D1R) y D2 y es degradada por las enzimas monoamino-oxidasa (MAO) y catecol-O-metiltransferasa (COMT). Nuestro propósito es estudiar el patrón de excreción urinaria de DA (UDAV) y la actividad de MAO y COMT durante el consumo de dietas con distinto contenido de sodio.

Rol del riñón en la hipertensión sal-sensible / Role of the kidney in salt sensitive hypertension

An important proportion of patients with essential hypertension are salt sensitive, defined as those who experience signifcant blood pressure changes according to the amount of salt intake. They have a disturbance in the pressure induced natriuresis mechanism and their kidneys have functional and morphological alterations con-sistent with an acquired tubulointerstitial alteration, afferent arteriole damage and alteration of peritubular capillaries. All these alterations lead to disturbances in sodium load excretion under normal pressures. There is also an associated activation of kidney vasoconstrictor/salt retaining systems and a reduction in the vasodilator/ salt eliminating mechanisms. These alterations, that originate early in life, generate a new blood pressure level, that corrects natriuresis at the expense of a sustained hypertension.

Patterns of renal dopamine release to regulate diuresis and natriuresis during volume expansion: Role of renal monoamine-oxidase / Perfiles de secreción de dopamina renal en la expansión de volumen para regular diuresis y natriuresis: Rol de la monoaminoxidasa renal

Diuretic and natriuretic effects of renal dopamine (DA) are well established. However, in volume expansion the pattern of renal DA release into urine (U DA V) and the role of enzymes involved in DA synthesis/degradation have not yet been defined. The objective was to determine the pattern of U DA V during volume expansion and to characterize the involvement of monoamine-oxidase (MAO) and aromatic amino-acid decarboxylase (AADC) in this response. In this study male Wistar rats were expanded with NaCl 0.9% at a rate of 5% BWt per hour. At the beginning of expansion three groups received a single drug injection as follows: C (vehicle, Control), IMAO (MAO inhibitor Pargyline, 20 mg/kg BWt, i.v.) and BNZ (AADC inhibitor Benserazide, 25 mg/kg BWt, i.v.). Results revealed that in C rats U DA V (ng/30 min/100g BWt) increased in the first 30 min expansion from 11.5 ± 1.20 to 21.8 ± 3.10 (p < 0.05) and decreased thereafter. IMAO showed a similar pattern but significantly higher than C at 30 min expansion (32.5 ± 2.20, p < 0.05). IMAO greatly reduced MAO activity from 8.29 ± 0.35 to 1.1 ± 0.03 nmol/mg tissue/hour and significantly increased diuresis and natriuresis over controls. BNZ abolished the early U DA V peak to 3.2±0.72 (p < 0.01) and though, U DA V increased over C after 60 min expansion, natriuresis and diuresis were diminished by BNZ treatment. Results indicate that an increment in renal DA release into urine occurs early in expansion and in a peak-shaped way. In this response MAO plays a predominant role.

La dopamina (DA) intrarrenal ejerce efectos diuréticos y natriuréticos. Sin embargo, en los estado de expansión de volumen aún no está bien definido el patrón de liberación de dopamina renal hacia la orina y si cumplen un rol las enzimas involucradas en la síntesis o degradación de la amina. El objetivo del presente trabajo fue determinar el patrón de excreción urinaria de DA (U DA V) durante la expansión de volumen, caracterizando la participación de las enzimas monoaminooxidasa (MAO) y decarboxilasa de aminoácidos aromáticos (AADC) en esta respuesta. Para ello ratas Wistar macho fueron expandidas de volumen con NaCl 0.9% al 5% del peso corporal por hora durante dos horas y divididas en tres grupos, los que al comienzo de la expansión recibieron: C (vehículo, Control), IMAO (Pargilina, inhibidor de MAO, 20 mg/kg PC, i.v.) y BNZ (Benserazida, inhibidor de AADC, 25 mg/kg PC, i.v.). Se observó que en C la U DA V (ng/30min/100gPC) aumentó durante los primeros 30 minutos de expansión de 11.5 ± 1.20 a 21.8 ± 3.10 (p < 0.05), disminuyendo posteriormente. IMAO mostró un patrón de liberación similar pero significativamente mayor que C a los 30 min de expansión (32.5 ± 2.20, p < 0.05). En este grupo la actividad de MAO disminuyó de 8.29 ± 0.35 a 1.1 ± 0.03 nmol/mg tejido/hora y aumentaron la diuresis y natriuresis por sobre los controles. En BNZ, el pico de U DA V observado a los 30 min de la expansión disminuyó a 3.2 ± 0.72 (p < 0.01), aunque luego de 60 minutos fue mayor que en C. BNZ disminuyó tanto la diuresis como la natriuresis. Podemos concluir que al comienzo de la expansión de volumen se produce un pico de excreción de dopamina renal hacia la orina. La enzima MAO juega un rol fundamental en esta respuesta.

Consequences of cerebroventricular insulin injection on renal sodium handling in rats: effect of inhibition of central nitric oxide synthase

In the present study, we investigated the effects of acute intracerebroventricular (icv) insulin administration on central mechanisms regulating urinary sodium excretion in simultaneously centrally NG-nitro-L-arginine methylester (L-NAME)-injected unanesthetized rats. Male Wistar-Hannover rats were randomly assigned to one of five groups: a) icv 0.15 M NaCl-injected rats (control, N = 10), b) icv dose-response (1.26, 12.6 and 126 ng/3 µL) insulin-injected rats (N = 10), c) rats icv injected with 60 µg L-NAME in combination with NaCl (N = 10) or d) with insulin (N = 10), and e) subcutaneously insulin-injected rats (N = 5). Centrally administered insulin produced an increase in urinary output of sodium (NaCl: 855.6 ± 85.1 Ä percent/min; 126 ng insulin: 2055 ± 310.6 Ä percent/min; P = 0.005) and potassium (NaCl: 460.4 ± 100 Ä percent/min; 126 ng insulin: 669.2 ± 60.8 Ä percent/min; P = 0.025). The urinary sodium excretion response to icv 126 ng insulin microinjection was significantly attenuated by combined administration of L-NAME (126 ng insulin: 1935 ± 258.3 Ä percent/min; L-NAME + 126 ng insulin: 582.3 ± 69.6 Ä percent/min; P = 0.01). Insulin-induced natriuresis occurred by increasing post-proximal sodium excretion, despite an unchanged glomerular filtration rate. Although the rationale for decreased urinary sodium excretion induced by combined icv L-NAME and insulin administration is unknown, it is tempting to suggest that perhaps one of the efferent signals triggered by insulin in the CNS may be nitrergic in nature.

Influence of renal denervation on blood pressure, sodium and water excretion in acute total obstructive apnea in rats

Obstructive apnea (OA) can exert significant effects on renal sympathetic nerve activity (RSNA) and hemodynamic parameters. The present study focuses on the modulatory actions of RSNA on OA-induced sodium and water retention. The experiments were performed in renal-denervated rats (D; N = 9), which were compared to sham (S; N = 9) rats. Mean arterial pressure (MAP) and heart rate (HR) were assessed via an intrafemoral catheter. A catheter was inserted into the bladder for urinary measurements. OA episodes were induced via occlusion of the catheter inserted into the trachea. After an equilibration period, OA was induced for 20 s every 2 min and the changes in urine, MAP, HR and RSNA were recorded. Renal denervation did not alter resting MAP (S: 113 ± 4 vs D: 115 ± 4 mmHg) or HR (S: 340 ± 12 vs D: 368 ± 11 bpm). An OA episode resulted in decreased HR and MAP in both groups, but D rats showed exacerbated hypotension and attenuated bradycardia (S: -12 ± 1 mmHg and -16 ± 2 bpm vs D: -16 ± 1 mmHg and 9 ± 2 bpm; P < 0.01). The basal urinary parameters did not change during or after OA in S rats. However, D rats showed significant increases both during and after OA. Renal sympathetic nerve activity in S rats increased (34 ± 9 percent) during apnea episodes. These results indicate that renal denervation induces elevations of sodium content and urine volume and alters bradycardia and hypotension patterns during total OA in unconscious rats.

BTCI enhances guanylin-induced natriuresis and promotes renal glomerular and tubular effects

Guanylin and uroguanylin are small cysteine-rich peptides involved in the regulation of fluid and electrolyte homeostasis through binding and activation of guanylyl cyclases signaling molecules expressed in intestine and kidney. Guanylin is less potent than uroguanylin as a natriuretic agent and is degraded in vitro by chymotrypsin due to unique structural features in the bioactive moiety of the peptide. Thus, the aim of this study was to verify whether or not guanylin is degraded by chymotrypsin-like proteases present in the kidney brush-border membranes. The isolated perfused rat kidney assay was used in this regard. Guanylin (0.2 µM) induced no changes in kidney function. However, when pretreated by the black-eyed pea trypsin and chymotrypsin inhibitor (BTCI - 1.0 µM; guanylin - 0.2 µM) it promoted increases in urine flow (deltaUF of 0.25 ± 0.09 mL.g-1/min, P < 0.05) and Na+ excretion ( percent delta ENa+ of 18.20 ± 2.17, P < 0.05). BTCI (1.0 µM) also increased percentENa+ (from 22.8 ± 1.30 to 34.4 ± 3.48, P < 0.05, 90 minutes). Furthermore, BTCI (3.0 µM) induced increases in glomerular filtration rate (GFR; from 0.96 ± 0.02 to 1.28 0.02 mL.g-1/min, P < 0.05, 60 minutes). The present paper strongly suggests that chymotrypsin-like proteases play a role in renal metabolism of guanylin and describes for the first time renal effects induced by a member of the Bowman-Birk family of protease inhibitors.

Guanilina e uroguanilina são peptídeos pequenos, ricos em cisteína, envolvidos na regulação da homeostase de fluidos e eletrólitos através da ligação e ativação da guanilato ciclase expressa no intestino e nos rins. A guanilina é menos potente do que a uroguanilina como agente natriurético e é degradada in vitro pela quimiotripsina devido a características estruturais únicas no domínio bioativo do peptídeo. Portanto o objetivo deste trabalho foi verificar se a guanilina é degradada por proteases tipo quimiotripsina, presentes na membrana da borda em escova dos rins. Para esta investigação, foi usado o modelo do rim isolado de rato perfundido. A Guanilina (0,2 µM) não induziu mudanças na função renal. Entretanto, quando pré-tratada com inibidor de tripsina e de quimiotripsina de black-eyed pea (BTCI - 1,0 µM; guanilina - 0,2 µM) promoveu um aumento no fluxo urinário (deltaUF de 0,25 ± 0,09 mL.g-1/min, P < 0,05) e na excreção de Na+ ( por centoDENa+ de 18,20 ± 2,17, P < 0,05). BTCI (1,0 µM) também aumenta por centoENa+ (de 22,8 ± 1,30 a 34,4 ± 3,48, P < 0,0590 minutos). Além disto, BTCI (3,0 µM) induziu um aumento da taxa de filtração glomerular (GFR; de 0,96 ± 0,02 para 1,28 ± 0,02 mL.g-1/min, P < 0,05, 60 minutos). O presente trabalho sugere fortemente que proteases semelhantes à quimiotripsina desempenham um papel no metabolismo renal de guanilinas e descreve, pela primeira vez, os efeitos renais induzidos por um membro da família de inibidores de proteases do tipo Bowman-Birk.

Syndromes related to sodium and arginine vasopressin alterations in post-operative neurosurgery

BACKGROUND: Cerebral salt wasting syndrome (CSWS), syndrome of inappropriate antidiuretic hormone secretion (SIADH) and diabetes insipidus (DI) are frequently found in postoperative neurosurgery. PURPOSE: To identify these syndromes following neurosurgery. METHOD: The study included 30 patients who had been submitted to tumor resection and cerebral aneurysm clipping. Sodium levels in serum and urine and urine volume were measured daily up to the 5th day following surgery. Plasma arginine vasopressin (AVP) was measured on the first, third and fifth days post-surgery. RESULTS: CSWS was found in 27/30 patients (90 percent), in 14 (46.7 percent) of whom it was associated with a reduction in the levels of plasma AVP (mix syndrome). SIADH was found in 3/30 patients (10 percent). There was no difference between the two groups of patients. CONCLUSION: CSWS was the most common syndrome found, and in half the cases it was associated with DI. SIADH was the least frequent syndrome found.

INTRODUÇÃO: A síndrome perdedora de sal (SPS), síndrome da secreção inapropriada do hormônio antidiurético (SIADH) e diabetes insipidus (DI) são freqüentemente encontradas no pós-operatório de neurocirurgia. OBJETIVO: Identificar essas síndromes relacionadas à neurocirurgia. MÉTODO: Foram estudados 30 pacientes submetidos à ressecção de tumor (n=19) e clipagem de aneurisma (n=11) cerebral durante os primeiros cinco dias do pós-operatório. Os pacientes foram submetidos a dosagens diárias de sódio sérico e urinário até o 5° dia pós-operatório, com controle de volume urinário neste período e dosagem de arginina-vasopressina (AVP) plasmática no 1°, 3° e 5° dias pós-operatórios. RESULTADOS: A SPS foi encontrada em 27/30 pacientes (90 por cento), em 14/27 (46,7 por cento) associada à diminuição dos níveis de AVP plasmática (síndrome mista). A SIADH foi encontrada em 3/30 pacientes (10 por cento). Não houve diferença entre os dois grupos de pacientes. CONCLUSÃO: A SPS foi a síndrome mais freqüente, em metade de casos associada ao DI. A SIADH foi a menos freqüente.

Sensibilidade gustativa ao sal, natriúria e pressão arterial em indivíduos normotensos / Salt taste threshold, 24 hour natriuresis and blood pressure variation in normotensive individuals

OBJETIVO: O estudo avalia sensibilidade gustativa ao sal, excreção urinária de sódio e pressão arterial (PA) em normotensos. A hipótese foi de que limiar de sensibilidade gustativa ao sal (LSGS) aumentado se associasse a maior natriúria em 24 horas e níveis aumentados de PA. MÉTODOS: Foram avaliados 24 voluntários sem diagnóstico de HA. Para avaliar LSGS, usou-se soluções de cloreto de sódio (NaCl) em diferentes concentrações. Os voluntários foram submetidos à monitorização ambulatorial da pressão arterial (MAPA) de 24 horas e coleta de urina de 24 horas para dosagem de sódio (NaU). Para análise, foram agrupados de acordo com o LSGS, aumentado ou normal. RESULTADOS: Os grupos não diferiram para idade, índice de massa corporal (IMC), variáveis demográficas, uso de álcool, fumo e PA. NaU foi significativamente maior no grupo com LSGS aumentado. Utilizando-se o coeficiente de correlação de Pearson, com significância determinada pelo teste t, houve correlação de forte intensidade entre médias de PA sistólica e diastólica com IMC, de regular intensidade entre LSGS e NaU, assim como para PA sistólica e NaU. CONCLUSÃO: Natriúria de 24 horas foi maior em indivíduos com LSGS aumentado, sugerindo que esta maior avidez ao sal determine maior ingestão de sódio. Houve forte associação entre PA e IMC. Não foi evidenciada associação entre LSGS e PA, diferente do já documentado em pacientes com PA aumentada. Aumentando-se o número de pessoas, faixa etária e pacientes com níveis pressóricos aumentados, talvez se respondam outras perguntas a respeito da relação entre LSGS, natriúria e PA.

OBJECTIVE: The study evaluates salt taste sensibility, urinary sodium excretion and blood pressure (BP) in normotensive persons. The hypothesis was that a higher salt taste threshold (STT) can be associated to a higher 24 hour natriuresis and increased BP levels. METHODS: Twenty four not hypertensive volunteers were selected. To evaluate STT, different concentrations of sodium chloride were used. Individuals were submitted to 24 hour ambulatory blood pressure monitoring (ABPM) and the 24 hour urine was collected for sodium dosage. Patients were divided in two groups related to higher or normal STT. RESULTS: Both groups did not differ regarding age or body mass index (BMI). There was no difference between the groups regarding demographic variables, alcohol or tobacco use, and ABPM. Twenty-four hour natriuresis was significantly higher in the group with increased STT. Using Pearson´s correlation coefficient, with the significance determined by Student-t test, there was a strong correlation between 24 hour Systolic BP and BMI, Diastolic BP and BMI, and a regular correlation between STT with 24 hour natriuresis and Systolic BP with 24 hour natriuresis. CONCLUSION: Twenty four hour natriuresis was significantly higher in individuals with higher STT, suggesting that this avidity for salt is followed by higher ingestion of sodium. There was strong association between BP and BMI. The association between STT and BP levels was not confirmed. Increasing the number of persons, the age bracket, and of hypertensive patients may lead to a better understanding of the relations between STT, natriuresis and BP variation.