Background Weight loss is a milestone in the prevention of chronic diseases associated with high morbility and mortality in industrialized countries. Very-low calorie ketogenic diets (VLCKDs) are increasingly used in clinical practice for weight loss and management of obesity-related comorbidities. Despite evidence on the clinical benefits of VLCKDs is rapidly emerging, some concern still exists about their potential risks and their use in the long-term, due to paucity of clinical studies. Notably, there is an important lack of guidelines on this topic, and the use and implementation of VLCKDs occurs vastly in the absence of clear evidence-based indications. Purpose We describe here the biochemistry, benefits and risks of VLCKDs, and provide recommendations on the correct use of this therapeutic approach for weight loss and management of metabolic diseases at different stages of life.

Speckle-tracking echocardiography has recently emerged as a quantitative ultrasound technique for accurately evaluating myocardial function by analyzing the motion of speckles identified on routine 2-dimensional sonograms. It provides non-Doppler, angle-independent, and objective quantification of myocardial deformation and left ventricular systolic and diastolic dynamics. By tracking the displacement of the speckles during the cardiac cycle, strain and the strain rate can be rapidly measured offline after adequate image acquisition. Data regarding the feasibility, accuracy, and clinical applications of speckle-tracking echocardiography are rapidly accumulating. This review describes the fundamental concepts of speckle-tracking echocardiography, illustrates how to obtain strain measurements using this technique, and discusses their recognized and developing clinical applications.

Background —In essential hypertension, endothelium-dependent vasodilation is impaired because of reduced nitric oxide (NO) availability, which is mainly caused by oxidative stress. The present study was designed to identify the mechanism(s) responsible for NO-independent vasodilation to bradykinin in patients with essential hypertension. Methods and Results —In 16 healthy subjects (49.5±5.8 years; 118.6±3.5/78.9±2.9 mm Hg) and 16 patients with essential hypertension (47.9±4.8 years; 154.6±4.5/102.9±3.2 mm Hg), we measured modifications in forearm blood flow (strain-gauge plethysmography) during intrabrachial infusion of bradykinin (5, 15, or 50 ng/100 mL of forearm tissue per minute) in the presence of saline, N ω -monomethyl- l -arginine (L-NMMA; used to inhibit NO synthase; 100 μg/100 mL of forearm tissue per minute), and ouabain (to block Na + K + /ATPase and prevent hyperpolarization; 0.7 μg/100 mL of forearm tissue per minute). In healthy subjects, vasodilatation to bradykinin was significantly blunted by L-NMMA and unaffected by ouabain. In hypertensive patients, vasodilatation to bradykinin was not modified by L-NMMA, but it was significantly reduced by ouabain. In an adjunctive group of 8 hypertensive patients (49.9±3.8 years; 155.9±5.5/103.7±3.9 mm Hg), the response to bradykinin was repeated during the administration of intrabrachial vitamin C (a scavenger for oxygen free radicals; 8 mg/100 mL of forearm tissue per minute). In these patients, L-NMMA–induced inhibition of vasodilation to bradykinin was restored, and ouabain was no longer effective. In a final group of 6 normotensive controls (45.9±4.1 years; 115.1±2.9/79.3±2.1 mm Hg), vasodilation to bradykinin residual to L-NMMA blockade was further inhibited by simultaneous ouabain infusion. Conclusions —Vasodilation to bradykinin is impaired in essential hypertensive patients because of an NO-system alteration caused by oxidative stress, and it is mediated by an alternative pathway, possibly involving endothelium-dependent hyperpolarization.

Endothelial dysfunction secondary to acute endogenous estrogen deprivation is caused by reduced NO availability. Cyclooxygenase-dependent production of oxidative stress could be responsible for this alteration.