Transient electrocardiographic changes following smoking cannabis.

We report a case of transient ECG abnormalities (negative T waves in the inferior leads) associated with presyncope related to acute cannabis consumption; after a few hours the ECG returned normal. Although pathophysiological mechanisms are not clear, it might be hypothesize a mismatch between increased oxygen demand and decreased oxygen supply or a marked hyperactivation of the sympathetic nervous system.

Increased urinary excretion of the epithelial Na channel activator prostasin in patients with primary aldosteronism.

OBJECTIVES: Prostasin is a glycosylphosphatidylinositol-anchored serine protease that is released in urine and is involved in epithelial Na channel activation. A direct association between urinary prostasin (u-prostasin) concentration and activation of the aldosterone-driven pathway has been suggested; however, in previous studies on primary aldosteronism, a semiquantitative evaluation, rather than a precise quantification, of prostasin was performed. We aim to investigate if u-prostasin concentrations are higher in patients with primary aldosteronism than in patients with essential hypertension and whether u-prostasin measurements could be a useful marker for diagnosing primary aldosteronism in hypertensive patients. METHODS: A total of 62 primary aldosteronism and 56 essential hypertension patients were enrolled. Biochemical and hormonal parameters were measured by applying routine laboratory methods, and u-prostasin levels were assessed by ELISA. RESULTS: Primary aldosteronism patients had higher u-prostasin levels than did essential hypertension patients. Prostasin levels were positively correlated with the aldosterone-to-renin ratio and inversely correlated with plasma K and urinary Na levels. In the highest concentration quartile, u-prostasin levels were associated with a several-fold higher probability of primary aldosteronism diagnosis in hypertensive patients. Receiver operating characteristic curve analysis showed that prostasin was specific but poorly sensitive as a diagnostic marker for primary aldosteronism. CONCLUSIONS: The study shows that an elevated u-prostasin concentration in humans is a specific marker for primary aldosteronism, which involves the classical model of epithelial Na channel activation. There was no statistically significant difference in prostasin concentrations among patients with different primary aldosteronism subtypes. Studies with a larger series of patients are necessary to clarify the clinical usefulness of the prostasin assay.

Apparent Mineralocorticoid Excess by a Novel Mutation and Epigenetic Modulation by HSD11B2 Promoter Methylation.

CONTEXT: Apparent mineralocorticoid excess (AME) is a rare autosomal recessive disease resulting from mutations within the hydroxysteroid (11ß-dehydrogenase2 [HSD11B2]) gene causing a prominent mineralocorticoid receptor activation by cortisol and hypokalemic low renin hypertension as the main clinical feature. OBJECTIVE: The objective of the study was to characterize AME for possible novel HSD11B2 mutations and to define the role of HSD11B2 promoter methylation in the phenotypic expression of the disease. SUBJECTS: Two proband brothers and 10 relatives participated in the study. METHODS: Peripheral blood mononuclear cell DNA was used for HSD11B2 exon sequencing, and a new predicted structure of 11ß-hydroxysteroid dehydrogenase type 2 was generated by an in silico three-dimensional modeling. Promoter methylation was determined by bisulfite pyrosequencing. Urinary tetrahydrocortisol plus allotetrahydrocortisol to tetrahydrocortisone ratio, a surrogate marker of 11ß-hydroxysteroid dehydrogenase type 2 activity, was measured by gas chromatography-mass spectrometry. RESULTS: A novel homozygous variant at HSD11B2 exon 3 site (c.C662G) resulting in an alanine-to-glycine change at position 221 was discovered by sequencing the DNA of the probands. A monoallelic mutation was found in the DNA of the parents and other four relatives. In silico three-dimensional modeling showed that the Ala221Gly substitution could perturb a hydrophobic interaction by reducing the enzymatic affinity for the substrate. The HSD11B2 promoter methylation of normotensive heterozygous relatives was similar to that of wild types, whereas the hypertensive heterozygous subjects showed higher methylation than wild types, consistently with a transcriptional repressive effect of promoter hypermethylation. CONCLUSIONS: A novel HSD11B2 functional mutation accounting for an Ala221Gly substitution causes AME. The hypertension phenotype is also epigenetically modulated by HSD11B2 methylation in subjects heterozygous for the mutation.