Browsing by Author "Soto, J"
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- ItemA(-6)G variant of angiotensinogen gene and aldosterone levels in hypertensives(1999) Fardella, C; Zamorano, P; Mosso, L; Gomez, L; Pinto, M; Soto, J; Oestreicher, E; Cortes, P; Claverie, X; Montero, J; NCD Risk Factor Collaboration (NCD-RisC)Recently, a novel mutation in the promoter region of the angiotensinogen gene that involves the presence of an adenine instead of a guanine 6 bp upstream from the transcription initiation site (A(-6)G) has been shown to induce an increase in gene transcription. The aim of this study was to determine the prevalence of the A(-6)G mutation in essential hypertensive patients and to correlate it with aldosterone and renin activity levels. We studied 191 hypertensives. We measured levels of aldosterone (plasma and urinary) and plasma renin activity. We determined the variants A and G using a mutagenically separated polymerase chain reaction technique. In 191 hypertensives, the A variant was detected in 266 of 382 (69.6%) and the G variant in 116 of 382 alleles (30.4%). Plasma aldosterone was significantly higher in patients homozygous for AA than in those homozygous for GG (369+/-208 versus 246+/-142 pmol/L). Urinary aldosterone was significantly higher in homozygous AA than in AG or GG patients (62.4+/-39.4 versus 50.8+/-25.2 and 37.4+/-22.3 nmol/d, respectively). When the patients were grouped according to the presence or absence of the A allele, the aldosterone levels and the plasma aldosterone/plasma renin activity ratio were significantly higher in patients with the A allele, The presence of the A variant was associated with higher levels of aldosterone. These results suggest that the presence of the A variant could determine the appearance of arterial hypertension through higher transcription activity of the angiotensinogen gene and concomitant aldosterone production.
- ItemEvidences for mineralocorticoid excess in essential hypertension(2000) Cortes, P; Fardella, C; Oestreicher, E; Gac, H; Mosso, L; Soto, J; Foradori, A; Claverie, X; Ahuad, J; Montero, JBackground: Primary hyperaldosteronism is more frequent among subjects with essential hypertension than previously thought. The prevalence, according to local and international evidence could fluctuate between 9 and 10%. Aim: To investigate if subjects with essential hypertension have different aldosterone and renin plasma levels than normotensive subjects. Patients and methods: One hundred twenty five subjects with essential hypertension, not receiving medications for a least two weeks prior to the study and 168 age and sex matched normotensive controls were studied. Blood was drawn between 9 and 10 AM during a sodium free diet to determine plasma aldosterone, plasma renin activity and potassium. Results: Plasma aldosterone was higher in hypertensive subjects than controls (11.6 +/- 7.6 and 9.9 +/- 5.1 ng/dl respectively; p = 0.04). Plasma renin activity was lower in hypertensives than controls (1.42 +/- 1.28 and 1.88 +/- 1.39 ng/ml/h respectively; p < 0.001). Thus, plasma aldosterone/plasma renin activity ratio was higher in hypertensives (13.8 +/- 13.5 and 8.3 +/- 7.8; p < 0.001), A pathological ratio was defined as over 25, corresponding to the mean plus two standard deviations of the control group. Primary hyperaldosteronism was found in 5/125 hypertensives (4%) and 1/168 normotensive subject (0.6%). None had hypokalemia. Conclusions: Subjects with essential hypertension have higher plasma aldosterone and lower plasma renin activity than normal controls. A plasma aldosterone/plasma renin activity over 25 was defined as abnormal.
- ItemHigh prevalence of undiagnosed primary hyperaldosteronism among patients with essential hypertension(1999) Mosso, L; Fardella, C; Montero, J; Rojas, P; Sanchez, O; Rojas, V; Rojas, A; Huete, A; Soto, J; Foradori, A; NCD Risk Factor Collaboration (NCD-RisC)Background: Classically, primary hyperaldosteronism was diagnosed in no more than 1% of patients with hypertension, when hypokalemia was used as the screening test. However, numerous patients with primary hyperaldosteronism do not have hypokalemia nod the disease remains undiagnosed. Aim: To assess the prevalence of normokalemic primary hyperaldosteronism among patients classified as having essential hypertension. Patients and methods: One hundred hypertensive patients with a blood pressure over 145/95 were studied. Plasma aldosterone and plasma renin activity were measured in all. A primary hyperaldosteronism was diagnosed when high aldosterone levels (over 16 ng/dl) and low plasma renin activity (below 0.5 ng/ml/h) coexisted in two blood tests of the aldosterone/plasma renin activity ratio was over 50. A probable primary hyperaldosteronism was diagnosed whet? the ratio was between 25 and 50 and these patients were subjected to a Fludrocortisone test to confirm the diagnosis. A dexametasone suppression test was done to discard glucocorticoid remediable aldosteronism. An adrenal TAC scan was done to all patients with primary hyperaldosteronism. Results: A diagnosis of primary hyperaldosteronism was reached in ten patients. Seven had elevated aldosterone and low plasma renin activity. In three the diagnosis was confirmed with the fludrocortisone test. All ten patients had normal serum potassium levels. Dexametasone suppression test was positive in three patients that normalized their blood pressure levels. Adrenal TAC scans showed an adenoma in one patient and hyperplasia in another. Conclusions: Primary hyperaldosteronism is more frequent than previously thought, it is overlooked when hypokalemia is used as the screening test and it can only be diagnosed measuring plasma aldosterone and renin activity.
- ItemNormokalemic primary hyperaldosteronism - A common cause of secondary hypertension.(1999) Mosso, L; Fardella, C; Montero, J; Rojas, P; Sanchez, O; Rojas, A; Soto, J; Foradori, A; Huete, A; NCD Risk Factor Collaboration (NCD-RisC)Recently, some genetic forms of hypertension have been well characterized. These forms can be globally called mineralocorticoid hypertension and are due to different alterations of the renin-angiotensin-aldosterone system (SRAA). Among these, classic primary hyperaldosteronism and its glucocorticoid remediable variety, in which hypertension is secondary to aldosterone production, must be considered. There are also conditions in which mineralocorticoid activity does not depend on aldosterone production. These conditions generate a hyporeninemic hyperaldosteronism, observed in Liddle syndrome, apparent mineralocorticoid hypertension, 11- and 17-hydroxilase deficiency, among others. The detection of these forms of hypertension is only feasible if the renin-angiotensin-aldosterone system is assessed, measuring renin and aldosterone levels. This article reviews these forms of hypertension, their clinical workup and their relevance in the usual hypertensive patients.
- ItemPrimary hyperaldosteronism in essential hypertensives: Prevalence, biochemical profile, and molecular biology(2000) Fardella, CE; Mosso, L; Gomez Sanchez, C; Cortes, P; Soto, J; Gomez, L; Pinto, M; Huete, A; Oestreicher, E; Foradori, A; Montero, JThere is evidence that primary aldosteronism (PA) may be common in patients with essential hypertension (EH) when determinations of serum aldosterone (SA), plasma renin activity(PRA), and the SA/PRA ratio are used as screening. An inherited form of primary hyperaldosteronism is the glucocorticoid-remediable aldosteronism (GRA) caused by an unequal crossing over between the CYP11B1 and CYP11B2 genes that results in a chimeric gene, which has aldosterone synthase activity regulated by ACTH. The aim of this study was to evaluate the prevalence of PA and the GRA in 305 EH patients and 205 normotensive controls. We measured SA (1-16 ng/dL) and PRA (1-2.5 ng/mL . h) and calculated the SA/PRA ratio in all patients. A SA/PRA ratio level greater than 25 was defined as being elevated. PA was diagnosed in the presence of high SA levels (>16 ng/dL), low PRA levels (<0.5 ng/mL . h), and very high SA/PRA ratio (>50). Probable PA was diagnosed when the SA/PRA ratio was more than 25 but the other criteria were not present. A Fludrocortisone test was done to confirm the diagnosis. GRA was differentiated from other forms of PA by: the aldosterone suppression test with dexamethasone, the high levels of 18-hydroxycortisol, and the genetic detection of the chimeric gene. In EH patients, 29 of 305 (9.5%) had PA, 13 of 29 met all the criteria for PA, and 16 of 29 were initially diagnosed as having a probable PA and confirmed by the fludrocortisone test. Plasma potassium was normal in all patients. The dexamethasone suppression test was positive for GRA in 10 of 29 and 18-hydroxycortisol levels were high in 2 of 29 patients who had also a chimeric gene. In normotensive subjects, 3 of 205 (1.46%) had PA, and 1 of 205 had a GRA. In summary, we found a high frequency of normokalemic PA in EH patients. A high proportion of PA suppressed SA with dexamethasone, but only a few had a chimeric gene or high levels of 18-hydroxycortisol. These results emphasize the need to further investigate EH patients.
- ItemSalt-wasting congenital adrenal hyperplasia: Detection of mutations in CYP21B gene in a Chilean population(ENDOCRINE SOC, 1998) Fardella, CE; Poggi, H; Pineda, P; Soto, J; Torrealba, I; Cattani, A; Oestreicher, E; Foradori, AThe steroid 21-hydroxylase deficiency (21OHD) is the most frequent cause of congenital adrenal hyperplasia. We have characterized the disease-causing mutations in the 21-hydroxylase genes of 63 patients with salt-wasting congenital adrenal hyperplasia from a Chilean population of Hispanic origin, a group that has been scarcely evaluated. Using allele-specific PCR, lesions were identified in 97 chromosomes out of 126 tested (77%). The most frequent findings were the gene deletion or large gene conversion (LGC) = 22.9%, I2 splice = 19%, R357W = 12.7%, and Q319X = 10.5%. We did not find alleles with the mutation F308insT and we found three alleles with the cluster E6. The frequency of the point mutation R357W was at least two times more frequent than the one found in Caucasians populations, but similar to that communicated in Asian populations; this finding may be explained by the Asian ancestry of our South-Amerindian population. The frequency of Q319X was also high, similar only to those patients studied in Italy and in a neighboring Argentinian population. In summary, this is a genetic characterization of 21OHD made in an almost pure Hispanic population in Latin America. The high frequency of deletion of CYP21B gene, I2 splice, R357W, and Q319X mutations probably reflects the European-Caucasian-Spanish influence of the conquerors, mixed with Amerindians of Asian ancestry and modulated by other European immigrations.
- ItemThe A-6G mutation in the angiotensinogen gene is associated to high levels of aldosterone in essential hypertensives(1999) Fardella, C; Zamorano, P; Gomez, L; Oestreicher, E; Pinto, M; Rojas, A; Montero, J; Soto, J; Mosso, L; Foradori, AThe treatment of papillary thyroid carcinoma of less than 10 mm diameter is a matter of controversy. The incidental finding of papillary microcarcinomas in autopsies is frequent and some authors postulate that these tumors are biologically inactive and should only be observed. We report a 21 years old woman with a papillary thyroid cancer of 6x5x5 mm and bilateral paratracheal metastases, that was subjected to a total thyroidectomy. She received 200 mCi of radioiodine. Two years after surgery, a new nodule of 9.6 mm diameter was detected by ultrasound, that was treated with a new dose of 200 mCi of radioiodine. One year later a suprasternal mass of 2 cm diameter and 3 enlarged lymph nodes were detected. She was subjected to a surgical lymph node dissection of the neck and the biopsy confirmed the presence of cancer. She received a new dose of 300 mCi of radioiodine. The mother of the patient had a 7 mm thyroid nodule that was also a papillary carcinoma.