Diagnostik und Indikation zum Klappenersatz bei asymptomatischer und symptomatischer Aorteninsuffizienz

Chronic volume overload is associated with dilatation and eccentric hypertrophy of the left ventricle (=ventricular remodeling). With the dilatation of the left ventricle and the shift of the pressure-volume-relationship to the right, the filling pressures can be kept normal despite severe regurgitation. Therefore, the patient with aortic regurgitation can remain asymptomatic over many years. Thus, the indication for aortic valve replacement in patients with severe aortic regurgitation is sometimes difficult and may lead to problems to choose the optimal time point for operation. As a general rule, symptomatic patients with severe aortic regurgitation should be operated as soon as possible. In asymptomatic patients with significant dilatation of the left ventricle and reduction of systolic pump function the therapy of choice is aortic valve replacement. Asymptomatic patients with normal left ventricular function have usually a good prognosis with a yearly mortality rate of approximately 0.04%. However, in the presence of significant dilatation of the left ventricle, i. e. enddiastolic chamber diameter more than 70 mm respectively endsystolic diameter more than 50 mm, patients have to be checked on a regular basis, i. e. in yearly intervals to detect left ventricular dysfunction in due time. According to the literature, asymptomatic patients with severe aortic regurgitation develop left ventricular dysfunction in a yearly rate of 4%. However, approximately 50% of all patients are even after 10 years asymptomatic. The indication for aortic valve replacement is given when the patient shows a deterioration of left ventricular function or becomes symptomatic. Valve replacement is also indicated in patients with an ejection fraction below 50% and/or endsystolic chamber diameter of more than 55 mm. Therapy of choice in symptomatic patients with severe aortic regurgitation is aortic valve replacement. In asymptomatic patients, operation depends on the degree of chamber dilatation respectively the severity of left ventricular dysfunction. In patients with severe aortic regurgitation but without clinical symptoms and moderate enlargement of the left ventricle regular check-ups in yearly intervals are indicated. In the presence of severe left ventricular dilatation check-ups should be performed on a half-year basis to prevent irreversible damage to the heart muscle.     

Nonsurgical pulmonary valve replacement: Why,when, and how?

Percutaneous transcatheter interventions for valve replacement or implantation is one of the most exciting developments in the field of interventional cardiology. Valvular stenosis has been treated by balloon dilatation with early and late results; however, treatment for valvular regurgitation has remained surgical until now. Most new designs have been investigated for implantation of valves in the left or right ventricular outflow tracts. Patients with surgery on the right ventricular outflow tract for congenital heart disease constitute the most common group for reoperations during late follow-up. Surgical pulmonary valve replacement can be performed with low mortality; however, it sets up a substrate for future operations. Also, the risk of cardiopulmonary bypass, infection, bleeding, and ventricular dysfunction remains. A transcatheter technique is likely to have more acceptance and may expand the indications for early intervention for right ventricular outflow tract dysfunction.     

Imaging Guidance for Transcatheter Mitral Valve Intervention on Prosthetic Valves,Rings, and Annular Calcification

Catheter-based interventions to improve mitral valve function are dependent on anatomic and functional information provided by noninvasive imaging to plan, perform, and evaluate each intervention. In this review we highlight the importance of imaging guidance for catheter-based interventions on prosthetic mitral valves, surgical rings, and native valve annular calcification. Both repair and replacement procedures are discussed. We review the general features common to this collection of procedures and discuss specific imaging issues and concerns for each procedure. Figures and intraprocedural videos emphasize central messages using case examples.     

Effects of pH and Nutrients (Nitrogen) on Growth and Toxin Profile of the Ciguatera-Causing Dinoflagellate Gambierdiscus polynesiensis (Dinophyceae)

Ciguatera poisoning is a foodborne disease caused by the consumption of seafood contaminated with ciguatoxins (CTXs) produced by dinoflagellates in the genera Gambierdiscus and Fukuyoa. Ciguatera outbreaks are expected to increase worldwide with global change, in particular as a function of its main drivers, including changes in sea surface temperature, acidification, and coastal eutrophication. In French Polynesia, G. polynesiensis is regarded as the dominant source of CTXs entering the food web. The effects of pH (8.4, 8.2, and 7.9), Nitrogen:Phosphorus ratios (24N:1P vs. 48N:1P), and nitrogen source (nitrates vs. urea) on growth rate, biomass, CTX levels, and profiles were examined in four clones of G. polynesiensis at different culture age (D10, D21, and D30). Results highlight a decrease in growth rate and cellular biomass at low pH when urea is used as a N source. No significant effect of pH, N:P ratio, and N source on the overall CTX content was observed. Up to ten distinct analogs of Pacific ciguatoxins (P-CTXs) could be detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in clone NHA4 grown in urea, at D21. Amounts of more oxidized P-CTX analogs also increased under the lowest pH condition. These data provide interesting leads for the custom production of CTX standards.     

Effects of intranasal oxytocin on pupil dilation indicate increased salience of socioaffective stimuli

To investigate the mechanisms by which oxytocin improves socioaffective processing, we measured behavioral and pupillometric data during a dynamic facial emotion recognition task. In a double‐blind between‐subjects design, 47 men received either 24 IU intranasal oxytocin (OXT) or a placebo (PLC). Participants in the OXT group recognized all facial expressions at lower intensity levels than did participants in the PLC group. Improved performance was accompanied by increased task‐related pupil dilation, indicating an increased recruitment of attentional resources. We also found increased pupil dilation during the processing of female compared with male faces. This gender‐specific stimulus effect diminished in the OXT group, in which pupil size specifically increased for male faces. Results suggest that improved emotion recognition after OXT treatment might be due to an intensified processing of stimuli that usually do not recruit much attention.     

Approaching dysphoric mood: State-effects of mindfulness meditation on frontal brain asymmetry

Meditation-based interventions reduce the relapse risk in recurrently depressed patients. Randomized trials utilizing neurophysiologic outcome measures, however, have yielded inconsistent results with regard to a prophylactic effect. Although frontal brain asymmetry, assessed through electroencephalographic (EEG) alpha activity (8–13 Hz), is indicative of approach vs. withdrawal-related response dispositions and represents a vulnerability marker of depression, clinical trials have provided mixed results as to whether meditation has beneficial effects on alpha asymmetry. Inconsistencies might have arisen since such trials relied on resting-state recordings, instead of active paradigms under challenge, as suggested by contemporary notions of alpha asymmetry.     

The tumor suppressor SirT2 regulates cell cycle progression and genome stability by modulating the mitotic deposition of H4K20 methylation

The establishment of the epigenetic mark H4K20me1 (monomethylation of H4K20) by PR-Set7 during G₂/M directly impacts S-phase progression and genome stability. However, the mechanisms involved in the regulation of this event are not well understood. Here we show that SirT2 regulates H4K20me1 deposition through the deacetylation of H4K16Ac (acetylation of H4K16) and determines the levels of H4K20me2/3 throughout the cell cycle. SirT2 binds and deacetylates PR-Set7 at K90, modulating its chromatin localization. Consistently, SirT2 depletion significantly reduces PR-Set7 chromatin levels, alters the size and number of PR-Set7 foci, and decreases the overall mitotic deposition of H4K20me1. Upon stress, the interaction between SirT2 and PR-Set7 increases along with the H4K20me1 levels, suggesting a novel mitotic checkpoint mechanism. SirT2 loss in mice induces significant defects associated with defective H4K20me1–3 levels. Accordingly, SirT2-deficient animals exhibit genomic instability and chromosomal aberrations and are prone to tumorigenesis. Our studies suggest that the dynamic cross-talk between the environment and the genome during mitosis determines the fate of the subsequent cell cycle.