[Alterations of calcium, magnesium, and zinc in essential hypertension:their relation to the renin-angiotensin-aldosterone system]. / Alteraciones del calcio, magnesio y zinc en hipertensión es ncial: sus relaciones con el sistema renina-angiotensina aldosterona.

Based on our studies at the Hypertension research unit, we have found that the renin-angiotensin aldosterone. System (RAAS) undergoes several changes being the following the most relevant: Low plasma renin concentration (LPRC), while the plasma Aldosterone concentration is high (HPAC). At the same time we found calcium metabolism alterations: High urine calcium excretion, low serum ionic calcium and high PTH level. This alterations are more evident if the elder patient become hypertensive. We have found this changes in several groups in our community: black, ancient, obese and diabetic patients; who more often suffer hypertension and they must be followed up closely. In this group there are the sodium dependent hypertensive and they are the one who can get beneficial effects from the low salt diet and high calcium intake. When we studied the low plasma renin hypertensive we found the calcium changes mentioned before in ancient patient, as well as, high urine Zinc excretion. When we gave and oral calcium supplement to these patients, we saw that the calcium and Zinc alterations mentioned before were corrected. The high plasma renin concentration hypertensive patients showed low serum magnesium concentration and high urine magnesium excretion. A brief comment on the possible role of oxidative stress on essential hypertension is made.

[Impact of the Hospital Coordinator Program on obtaining kidneys for renal transplantation]. / Impacto del Programa de Coordinadores Hospitalarios en la obtención de riñones para trasplante renal.

Limited organ supply is currently the major obstacle to the transplantation programs around the world. As an alternative to increase the organ donation rate, we undertook a preliminary transplant coordinator program study, during a 6 month period, in five public hospitals, as part of the National Transplant Program of the Centro Nacional de Diálisis y Trasplante. The primary objective of the Transplant Coordinator Program was donor detection and organ procurement, along with education of the community. Forty five predonors were detected, with an average age of 25.8 +/- 1.6 years, of these, 36 were men (80%). None of them was a voluntary donor. The most frequent diagnoses were cranial trauma in 57.8% and stroke in 22.2% Forty two percent (42.3%) of the predonors were detected in the emergency room, 33.3% in intensive care units and 24.4% in the surgery recovery room. The conversion rate of predonors to donors were 29%. The main causes for not conversion of predonors into donors were: family refusal 44%, sepsis 13%, cardiac arrest 13%, and reduced renal function 6%. In conclusion, the Transplant Coordinator Program allows to increase the predonor detection and gives good information for adequate management of donor and public educational campaign about the subject.

El riñon en la hipertensión arterial esencial / The kidney in te essential arterial hypertensión

No está bien dilucidada la posibilidad de que una hipertensión arterial esencial (HAE) leve-moderada sea capaz de llevar a un paciente a una insuficiencia renal crónica terminal (IRCT). Se planificó este trabajo con el objeto de estudiar los cambios que se producen en el riñon de pacientes con hipertensión esencial leve-moderada (n=148) reflejados sobre la depuración de creatinina (método de Jaffé) y de la excreción urinaria de albúmina (microalbuminuria), método del ácido sulfosalicílico), al compararlos con un grupo de sujetos normotensos (N=192). Los hipertensos presentaron una correlación inversa y significativa entre tensión arterial sistólica (TAS) (p<0,0001), tensión arterial diastólica (TAD), con la depuración de creatinina. Así mismo se encontró una correlación directa y muy significativa entre TAS (p<0,0001) y TAD (p<0,0001), con la excreción urinaria de albúmina. La TAS influyó más efectivamente sobre ambos parámetros. Esta acción se manifesto precozmente en los jóvenes (15-30 años) y se acentúa en los ancianos. La tensión arterial elevada se va a sumar a la edad para que la decline la función renal y se incremente la microalbuminuria, aunque moderadamente. El 38 por ciento de los hipertensos estudiados (15-60 años) presentaron microalbuminuria. En los mayores de 60 años, esta cifra se incrementa a un 55 por ciento. En el grupo de hipertensos entre los 30-60 años, se encontraron cifras más elevadas de aldosterona plasmática (p<0,0001) y una correlación significativa entre AP y microalbuminuria (p<0,01). La HAE leve-moderada, se suma al factor edad para alterar la función renal, aunque de manera moderada. Pensamos que esta alteración sí puede llevar al paciente a una IRCT, pero en un porcentaje bajo (15-60 años) presentaron microalbuminuria, cifra que aumentó a un 55 por ciento, por encima de 60 años. Estos son los pacientes que necesitan un control más estricto de hipertensión. En el grupo de hipertensión comprendida entre 30-60 años; sugerimos que la angiotensina II y la aldosterona deben jugar un papel contribuidor importante en la patogenia de la microalbuminuria

El péptido natriurético auricular y el sistema renina-aldosterona en el anciano normal y en el hipertenso: respuesta a los suplementos del calcio / Atrial natriuretic peptide and the system renin-angiotensin in the normal age and hypertense: response to calcium supplementation

La concentración plasmática del péctido natriurético auricular se encuentra elevada en los ancianos y si son hipertensos, sus valores son mucho mas altos. Con el objeto de estudiar el péptido natriurético auricular y la respuesta del sistema angiotensina aldosterona, se le administró un suplemento de calcio oral a un grupo de ancianos hipertensos y a otro grupo de normotensos, que nos sirvió de control. Se seleccionaron 22 ancianos hipertensos (2 hombres y 20 mujeres) con una edad de 75 ñ 7 años y 10 ancianos normotensos (2 hombres y 8 mujeres) con igual promedio de edad. Se le practicaron tomas tensionales con esfigmomanómetro de Hg en tres posiciones (decúbito, sentado y de pie). Por el método de radioinmunoensayo se les dosificaron el péptido natriurético auricular, la actividad de la renina plasmática, la aldosterona plasmática. Por absorción atómica se determinó el calcio sérico total, antes y después de recibir 1,5 g/día de Ca CO3 por un período de 4 semanas. En los hipertensos se obtuvieron los siguientes resultados: el péptido natriurético auricular descendió de manera importante (p<0,001), en igual forma lo hizo la aldosterona (p<0,001), por el contrario la renina (p<0,001) y el calcio (p<0,001), aumentaron sus valores. Igualmente se consiguieron las correlaciones inversas entre renina/péptido y entre péptido/calcio, pero no se observó esta relación entre aldosterona/péptido. En los ancianos normotensos, se obtuvo un descenso del péptido (p<0,05) y un incremento del calcio sérico total (p<0,05). En los hipertensos descendieron sus cifras tensionales sistólica (p<0,001) y las distólicas (p<0,05). Estos resultados ponen en evidencia las relaciones tan estrechas que existen entre la tensión arterial (especialmente la sistólica), péptido , renina, aldosterona, calcio sérico en ancianos hipertensos y menos significativos en los normotensos. En conclusión: la administración de calcio oral a ancianos, especialmente hipertensos, determinó en ellos una serie de cambios en los grupos hormonales que manejan la homeostasis agua-sodio. Esta acción se ejerce probablemente de manera indirecta, ya que al actuar como hipotensor, se van a corregir las alteraciones antes mencionadas en los dos grupos hormonales que intervienen en este equilibrio

Perfil bioquímico-hormonal de hipertensos esenciales respondedores y no respondedores a nifedipina / Biochemical-hormonal profile essential hypertensive patients response and no response to nifedipin

Con el objeto de determinar sus perfiles bioquímicos hormonales se estudiaron 21 pacientes portadores de una Hipertensión Arterial Esencial, respondedores a NIFEDIPINA (R) y 21 pacientes no respondieron (NR), cuyas características demográficas eran muy semejantes entre si. Se les determinaron: calcio sérico total (CaST), calcio Iónico sérico (Ca++) magnesio sérico (Mg++) fósforo sérico (Ps), igualmente se dosificó la excreción urinaria de estos electrolitos. También se estudio su sistema Renina-Angiotensina Aldosterona (RAA), dosificado la Actividad de Renina Plasmática (ARP), la Aldosterona Plasmática (AP) y los valores de Paratohormona (PTH). Se obtuvieron los siguientes resultados: En R encontramos Ca++ más bajo (p<0,001) CaST más bajo (p<0,05) y PTH más elevado (p<0,001), con una ARP más baja (p<0,001) que correlaciona directa y significativa con el Ca++ (p<0,001). En la orina se encontró un incremento en la excreción de calcio (p<0,001). En los NR en cambio, se observó un Mg++ más bajo (p<0,001) una AP más elevada (p<0,001) que correlacionó de manera inversa y significativa con la AP (Mg++/AP=P<0,001). Así mismo se encontró una excreción de Mg aumentada (P<0,001). a) Se separaron dos grupos, donde la fisiopatología de su hipertensión eran diferentes, en los R se caracterizó por alteraciones más evidentes del metabolismo del Calcio, en cambio en los NR las alteraciones eran más evidentes en el Magnesio. b) Estas alteraciones estaban íntimamente relacionadas con el Sistema RAA. c) El riñon debe jugar papel importante en estas alteraciones. d) Se plantea la posibilidad de que si conocemos algunas alteraciones Ca-Mg en un sujeto hipertenso podremos iniciar su terapia de manera más lógica, lo cual debe ser motivo de investigaciones posteriores

Normotension with decreased plasma renin activity and low serum ionic calcium levels: a prehypertensive state?

We studied the relationships between the renin-angiotensin-aldosterone system and calcium and magnesium levels in both serum and urine in 51 volunteer normotensive subjects, divided into two groups. Group 1 was made up of the 25 subjects whose levels of plasma renin activity were the lowest (1.93 +/- 0.70 ng/ml/hr). Group 2 comprised the 26 subjects with the highest plasma renin activity levels (4.80 +/- 0.84 ng/ml/hr). The following parameters were measured on all subjects: plasma renin activity and plasma and urinary aldosterone levels (by radioimmunoassay), serum ionic calcium levels (by Nova-2), total serum calcium, and serum and urinary magnesium values (by atomic absorption), serum and urinary sodium and potassium levels (by flame photometry), and creatinine clearance. In the group with low plasma renin activity (group 1), our findings included low serum ionic calcium levels (P less than .001); high coefficients of plasma aldosterone/plasma renin activity and urinary aldosterone/plasma renin activity (P less than .001); a significant correlation between the serum ionic calcium level and plasma renin activity (P less than .001); and an inverse correlation between systolic arterial tension and the serum ionic calcium level (P less than .05). These changes were more similar to change described in hypertensive patients with low plasma renin activity than to the findings in group 2 subjects. We speculate that normotensive subjects with low plasma renin activity present significant changes in the relationship between the renin-angiotensin-aldosterone system and sodium and calcium levels, and that this group is at risk for hypertension. A diet low in sodium and high in calcium could be an effective preventive measure.

The relationship between low plasma renin activity, low serum ionic calcium, and elevated systolic arterial tension in the normotensive elderly.

Plasma renin activity, plasma and urinary aldosterone, and serum and urinary calcium and magnesium were studied in forty elderly normotensive subjects and 37 normotensive young adult controls. Arterial tension was also recorded for each subject. The most important findings were significantly lower levels (P less than 0.001) of plasma renin activity, urinary aldosterone, and serum ionic calcium in the elderly group. A significant positive correlation was shown between calcium and plasma renin activity (P less than 0.001); an inverse correlation was found between systolic arterial tension and calcium (P less than 0.001). These findings indicate age-related physiological changes between the renin-aldosterone system, calcium, and systolic arterial tension. These changes are similar to those found previously in young adult hypertensives with low plasma renin activity levels, suggesting that the arterial tension of the elderly is labile, and that changes in the renin-angiotensin-aldosterone system (RAA) and calcium levels directly influence the increase of systolic arterial tension, which is frequently found in the elderly.

Aldosterona plasmática y urinaria: la actividad de la renina plasmática en sujetos normales / Aldosterone plasmatic and urinary: plasma renin activity in elderly normal subject

Con el objeto de estudiar las variaciones de los índices AP/ARP y AU/ARP en sujetos normales de edad avanzada, así como la influencia que ejercen sobre ellos la edad y la función renal, se seleccionaron 21 sujetos ancianos (79 ñ 9 años), nueve hombres y doce mujeres, y se compararon con 24 sujetos normales de menor edad (39 ñ 10 años), trece hombres y once mujeres, estudiados bajo las mismas condiciones. El hallazgo más importante que se encontró en este trabajo, fue una correlación inversa y estadísticamente muy significativa entre dichos índices y la función renal (p < 0,001), por lo que deducimos que en los ancianos la caída de la función renal debe ejercer alguna influencia sobre el incremento de los valores de estos índices. Los valores de la AP, relativamente más elevados, que presentan estos sujetos, podrían ser un mecanismo compensatorio para mantener la homeostasis del potasio en ancianos

Aldosterona plasmática y urinaria: la actividad de la renina plasmática en sujetos normales / Aldosterone plasmatic and urinary: plasma renin activity in elderly normal subject

Con el objeto de estudiar las variaciones de los índices AP/ARP y AU/ARP en sujetos normales de edad avanzada, así como la influencia que ejercen sobre ellos la edad y la función renal, se seleccionaron 21 sujetos ancianos (79 ñ 9 años), nueve hombres y doce mujeres, y se compararon con 24 sujetos normales de menor edad (39 ñ 10 años), trece hombres y once mujeres, estudiados bajo las mismas condiciones. El hallazgo más importante que se encontró en este trabajo, fue una correlación inversa y estadísticamente muy significativa entre dichos índices y la función renal (p < 0,001), por lo que deducimos que en los ancianos la caída de la función renal debe ejercer alguna influencia sobre el incremento de los valores de estos índices. Los valores de la AP, relativamente más elevados, que presentan estos sujetos, podrían ser un mecanismo compensatorio para mantener la homeostasis del potasio en ancianos (AU)

Changes in calcium and magnesium metabolism in essential arterial hypertension.

We studied 60 hypertensive patients (35 men and 25 women with an average age of 40 years) for signs of metabolic changes, with special emphasis on the relationship between the calcium and magnesium levels. The control group comprised 37 normotensive subjects (19 men and 18 women with an average age of 39 years). We studied the total serum calcium level (measured by atomic absorption), the ionized serum calcium level (by Nova 2 testing), and the plasma protein level, and we did coefficiency studies of the creatinine clearance and calcium and magnesium levels in 24-hour urine collections. In the hypertensive group, the ionized calcium level was significantly lower than that of the control subjects (P less than .001); the total serum calcium level was also lower, but the difference was of less statistical significance (P less than .05). There was no difference in serum magnesium levels between the two groups. There was a highly significant correlation between the total serum calcium level and the serum magnesium level (P less than .001) in the normal subjects; this correlation was not found in the hypertensive group. An increase in calcium and magnesium excretion was found in the 24-hour urine collections of the hypertensive group (P less than .001) (coefficient expressed as fractionated excretion of calcium and magnesium). There was also a high correlation between urinary excretion of calcium and magnesium (P less than .001) in the hypertensive subjects. Thus, the hypertensive subjects had changes in calcium metabolism that were related to magnesium levels. We suggest, therefore, that these two factors be studied simultaneously in evaluating patients with essential arterial hypertension.

Aldosterone and magnesium in essential arterial hypertension.

Thirty mildly hypertensive patients and 27 patients with severe essential hypertension and high levels of aldosterone were selected for a study of the relationship between plasma aldosterone and magnesium in essential arterial hypertension; levels of calcium and potassium were also studied. Thirty-six individuals were used as a control group. Our findings indicate that as plasma aldosterone levels increase, serum magnesium levels decrease correspondingly: in mild hypertensives with low levels of plasma aldosterone p less than 0.05 and in the most severely hypertensive patients with high levels of plasma aldosterone p less than 0.001. In this latter group we also found an inverse correlation between serum magnesium and systolic arterial pressure (p less than 0.001) and diastolic pressure (p less than 0.01). In these patients a significant increase in urinary excretion of magnesium was found, with levels 3 times higher than in the control group. These findings suggest a close relationship between changes in plasma aldosterone and magnesium. Possibly the aldosterone contributes through this mechanism to maintaining the hypertensive state in essential arterial hypertension. This action is exercised directly through the kidney, leading to a small but constant urinary loss of magnesium. This in turn leads to a chronic depletion of magnesium in hypertensives who have high levels of plasma renin activity and highly elevated plasma aldosterone.

Essential arterial hypertension: plasma and urinary aldosterone alterations.

We studied 52 patients with mild to severe essential arterial hypertension and ranging in age from 30 to 60 years (average, 44). Various biochemical and endocrinologic parameters were studied, with special emphasis on plasma aldosterone and urinary aldosterone. At the same time, a control group of 30 normal subjects (nonhypertensive) were studied under the same conditions. Both groups were carefully selected. Results indicated that the hypertensive group demonstrated a marked increase in plasma aldosterone levels (P less than .01) and an increase in the coefficient of plasma aldosterone/plasma renin activity (P less than .01). This indicates inadequate secretion of plasma aldosterone. There were no significant changes in the urinary aldosterone. Statistically significant changes were found in plasma renin activity (P less than .001) and plasma aldosterone (P less than .001) when the hypertensive patients were divided into two age groups, those under 45 and those over 45. These changes were not found in the normal subjects in the same age groups, indicating that age is an important influence on the renin-aldosterone system in hypertensive patients, and leads to variations in this hormonal axis similar to those observed in normal elderly subjects.

Urinary excretion of zinc in patients with essential arterial hypertension.

We report the finding of an increase in urinary zinc excretion in patients suffering from essential arterial hypertension; we find no clear explanation for this phenomenon. However, it merits a more thorough study, such as a comparison of zinc metabolism as altered by the hypertensive process. Also, urinary zinc excretion before and after (6 months) Captopril administration is reported.

Valores del sistema renina-angiotensina-aldosterona y de otras variables fisiologicas en sujetos venezolanos normales. / Values of the renin-angiotensin-aldosterone system and other physiological variables in normal Venezuelan subjects

Con el objeto de conocer cuales son los valores normales del sistema Renina-Angiotensina-Aldosterona (RAA) en nuestra poblacion grupo etnico muy heterogeneo, y de cuales son los factores que mas influyen sobre este eje hormonal, se estudiaron 125 sujetos venezolanos normales (72 mujeres y 53 hombres), en edades comprendidas entre los 13 y los 90 anos, en sus condiciones habituales de vida. El sistema RAA, se estimulo por 2 a 3 horas de deambulacion y los sujetos recibian su dieta habitual de sodio y potasio. Igualmente se estudiaron una serie de parametros fisiologicos. La edad juega un papel definitivo para poder considerar los valores normales, observandose diferencias estadisticamente significativas entre la Actividad de Renina Plasmatica (ARP) (p<0.001) y Aldosterona Urinaria (AU) (p<0.001) al colocarlos en dos grupos, antes y despues de 60 anos. Con la Aldosterona Serica (AS) hay diferencias tambien, aunque estadisticamente no significativas. El otro factor a tener en cuenta es la ingesta diaria de sodio.Se observo una estrecha correlacion entre ARP y excrecion diaria de sodio, siempre y cuando esta ultima fuera menor de 250 mEq/24 hrs. Con la AS y AU se mantiene esta correlacion, aun con excreciones mayores diarias de sodio. La respuesta de la RAA, a la ingesta diaria de sodio, es diferente antes y despues de los 60 anos. Los ancianos muestran una respuesta mas debil al compararlas, con los individuos mas jovenes

The renin-angiotensin-aldosterone system in normal elderly subjects.

In order to observe alterations of the Renin-Angiotensin-Aldosterone (RAA) system in elderly individuals, 40 healthy Venezuelan mestizos (8 men, 32 women) over 60 years of age were examined. These subjects had a normal sodium and potassium diet and were living under normal conditions. Plasma Renin Activity (PRA), urinary and serum aldosterone levels were determined by radioimmunoassay after two hours of ambulation. Values obtained were compared to those of a similar control group under age 60. The study of the RAA system demonstrated a correlation between PRA, serum and urinary aldosterone, and the daily excretion of sodium, even though less significant than in younger subjects. A continuous, gradual descent in these parameters was observed to be related to the advancement of age until approximately age 60, at which time the PRA demonstrated a sudden drop which was not accompanied by a decrease in the level of aldosterone. The most significant changes occur around the sixth decade of life when these hormone levels drop suddenly and the relationship between PRA, urinary and serum aldosterone changes.

[Relation between plasma renin and other variables. An evaluation in the Venezuelan population]. / Relaciones entre actividad de la renina plasmática y otras variables. Una evaluación en la población venezolana.

The plasma renin activity (PRA) was determined by radioimmunoassay in 102 subjects with normal blood pressure. In this group, 56 were female and 46 male, their ages ranged between 13 and 90 years, they were not receiving any medication and their diet contained normal amounts of sodium and potassium. In addition to the PRA measurements, their weight, height, blood pressure, hemoglobin, hematocrit, serum and urinary sodium, potassium, chloride as well as proteinuria and creatinine clearance were studied. A significative correlation was found between the PRA and age. However, no correlation was found between PRA and urinary sodium. The subjects were also divided in three groups: I. less than 30 years old. II. between 30 and 60 years old, and III. over 60 years. A significative correlation between PRA and urinary sodium was found in group II. These results in group II could be explained by the finding of a daily urinary sodium excretion below 250 mEq. Age has a definite influence between PRA and urinary sodium. We found that important changes in the response of the yuxtaglomerular apparatus to the intake of sodium develop around the age of 60. In group II is where we found a more stable equilibrium in PRA. In group I, the response of the PRA to a low intake of sodium was faster and violent, where as in group III the response was slower. Finally we think it is very important in these type of studies to follow very strict methodology, because it is the only way to establish comparisons between the different ethnic groups.