Multivariate Analysis of Correspondence between Left Atrial Volumes Assessed by Echocardiography and 3-Dimensional Electroanatomic Mapping in Patients with Atrial Fibrillation

Background

Left atrial (LA) enlargement is a predictor of worse outcome after catheter ablation for atrial fibrillation (AF). Widely used two-dimensional (2D)-echocardiography is inaccurate and underestimates real LA volume (LAV). We hypothesized that baseline clinical characteristics of patients can be used to adjust 2D-ECHO indices of LAV in order to minimize this disagreement.

Methods

The study enrolled 535 patients (59 ± 9 years; 67% males; 43% paroxysmal AF) who underwent catheter ablation for AF in three specialized centers. We investigated multivariately the relationship between 2D-echocardiographic indices of LA size, specifically LA diameter in M-mode in the parasternal long-axis view (LAD), LAV assessed by the prolate-ellipsoid method (LAV_Ellipsoid), LAV by the planimetric method (LAV_Planimetry), and LAV derived from 3D-electroanatomic mapping (LAV_CARTO).

Results

Cubed LAD of 106 ± 45 ml, LAV_Ellipsoid of 72 ± 24 ml and LAV_Planimetry of 88 ± 30 ml correlated only modestly (r = 0.60, 0.69, and 0.53, respectively) with LAV_CARTO of 137 ± 46 ml, which was significantly underestimated with a bias (±1.96 standard deviation) of -31 (-111; +49) ml, -64 (-132; +2) ml, and -49 (-125; +27) ml, respectively; p < 0.0001 for their mutual difference. LA enlargement itself, age, gender, type of AF, and the presence of structural heart disease were independent confounders of measurement error of 2D-echocardiographic LAV.

Conclusion

Accuracy and precision of all 2D-echocardiographic LAV indices are poor. Their agreement with true LAV can be significantly improved by multivariate adjustment to clinical characteristics of patients.     

The first dinosaur egg from the Lower Cretaceous of Western Siberia,Russia

The Lower Cretaceous Ilek Formation in Western Siberia (Russia) has yielded various vertebrate fossils, including skeletal remains of dinosaurs. Here we report on a fragmentary theropod egg from the vertebrate locality Shestakovo 3 of the Ilek Formation in Kemerovo Province. We assign the specimen to the oogenus Prismatoolithus (oofamily Prismatoolithidae) as Prismatoolithus ilekensis oosp. nov., on the basis of the following unique combination of characters: ovoid-shaped egg; thin eggshell 300–330 μm thick; angustiprismatic morphotype; eggshell with three different layers; gradual transition between mammillary layer and prismatic layer; abrupt contact between prismatic layer and external layer; mammillary layer to prismatic layer to external layer thickness ratio is 1:3:0.6; prismatic layer with ill-defined squamatic texture; angusticanaliculate pore system; and smooth outer surface. Like other Early Creataceous Prismatoolithus, the egg of Prismatoolithus ilekensis oosp. nov. was laid by a small bodied theropod dinosaur (troodontid or primitive bird) and this taxonomic attribution is supported by results of our phylogenetic analysis. Prismatoolithus ilekensis oosp. nov. is the first Early Cretaceous ootaxon from Russia.

urn:lsid:zoobank.org:act:734EAD40-86C3-488B-A61E-B5FF7378BC0E     

Phosphoproteomics of human platelets: A quest for novel activation pathways

Besides their role in hemostasis, platelets are also highly involved in the pathogenesis and progression of cardiovascular diseases. Since important and initial steps of platelet activation and aggregation are regulated by phosphorylation events, a comprehensive study aimed at the characterization of phosphorylation-driven signaling cascades might lead to the identification of new target proteins for clinical research. However, it becomes increasingly evident that only a comprehensive phosphoproteomic approach may help to characterize functional protein networks and their dynamic alteration during physiological and pathophysiological processes in platelets. In this review, we discuss current methodologies in phosphoproteome research including their potentials as well as limitations, from sample preparation to classical approaches like radiolabeling and state-of-the-art mass spectrometry techniques.     

Obesity as an Obstetric Risk Factor: Does It Matter in a Perinatal Center?

Objectives: Obesity before and during pregnancy is associated with several obstetrics risk factors for both mother and fetus. The aim of this retrospective study was to analyze the influence of BMI before pregnancy on distinct perinatal parameters. Research Methods and Procedures: The study includes 5067 singleton pregnancies from 2001 to 2004 at the Department of Obstetrics and Gynecology, University of Leipzig. The study group was divided into BMI groups: <18.5, ≥18.5 to <25, ≥25 to <30, ≥30 to <35, ≥35 to <40, and ≥40 kg/m². Analysis of perinatal data included rate of intrauterine death, rate of cesarean section and shoulder dystocia, time of hospital stay for mother and newborn, and gestational age of delivery. Neonatal outcome variables included percentage of newborns weighing >4000 grams, rate of umbilical cord pH <7.10, and rate of 1‐, 5‐, and 10‐minute Apgar scores of <8. Results: There was no difference in the gestational age at delivery among the groups. In the group with BMI ≥30 kg/m², the cesarean section rate was significantly elevated to 25.1%, with a more dramatic increase up to 30.2% in the group with BMI ≥35 kg/m² and 43.1% in the group with BMI ≥40 kg/m², mainly because of a higher number of secondary cesarean sections. Although newborns of obese women showed worse initial neonatal adaptation, the 10‐minute Apgar values did not differ among the groups. The higher rate of operative deliveries and the trend to an increased rate of shoulder dystocia did not influence duration of the hospital stay for mothers and newborns or morbidity of both. Discussion: A high pre‐pregnancy BMI is clearly associated with a higher rate of cesarean section deliveries. However, under the compensating conditions of a tertiary perinatal center, overall morbidity of mothers and newborns seems not to be increased.     

Synthesis of (5Z,8Z,11Z,14Z)-18- and 19-azidoeicosa-5,8,11,14-tetraenoic acids and their [5,6,8,9,11,12,14,15-3H8]-analogues through a common synthetic route

Total synthesis of (5Z,8Z,11Z,14Z)-18- and 19-azidoeicosa-5,8,11,14-tetraenoic acids and their [5,6,8,9,11,12,14,15-³H₈]-analogues via the corresponding p-toluenesulphonates is reported. This synthetic approach allows the preparation of radioactively labelled arachidonic acid derivatives following a common synthetic route. Activity assays indicated that 15-lipoxygenases may tolerate the azido group in the substrate binding pocket and thus, radioactively labelled azido compounds may be used as photo-affinity probes to investigate mechanistic features of eicosanoid biosynthesis.     

Stabilisation of tyrosinase by reversed micelles for bioelectrocatalysis in dry organic media

The enzymatic and bioelectrocatalytic activity of tyrosinase from mushrooms was studied in a system of reversed micelles formed by Aerosol OT (AOT) in hexane. The optimal catechol oxidising activity of tyrosinase incorporated in reversed micelles was found at a hydration degree of w(0)=25. The catalytic activity was comparable with tyrosinase activity in aqueous media. When immobilized at an Au electrode, either directly or in reversed micelles, tyrosinase exhibited a similar efficiency of the bioelectrocatalytic reduction of O(2) mediated by catechol; however, a rapid decrease in the activity correlated with the destruction of reversed micelles and/or the removal of tyrosinase from the electrode surface. The system containing tyrosinase in reversed micelles with caoutchouk, spread on the surface of the Au electrode and successively covered with a Nafion membrane layer, was found to result in stable tyrosinase-modified electrodes, which were resistant to inactivation in dry acetonitrile. The proposed technique offers possibilities for further development of highly active and stable surfactant/enzyme-modified electrodes for measurements carried out in organic solvents.     

Treeline advances along the Urals mountain range – driven by improved winter conditions?

High‐altitude treelines are temperature‐limited vegetation boundaries, but little quantitative evidence exists about the impact of climate change on treelines in untouched areas of Russia. Here, we estimated how forest‐tundra ecotones have changed during the last century along the Ural mountains. In the South, North, Sub‐Polar, and Polar Urals, we compared 450 historical and recent photographs and determined the ages of 11 100 trees along 16 altitudinal gradients. In these four regions, boundaries of open and closed forests (crown covers above 20% and 40%) expanded upwards by 4 to 8 m in altitude per decade. Results strongly suggest that snow was an important driver for these forest advances: (i) Winter precipitation has increased substantially throughout the Urals (~7 mm decade^?1), which corresponds to almost a doubling in the Polar Urals, while summer temperatures have only changed slightly (~0.05 °C decade^?1). (ii) There was a positive correlation between canopy cover, snow height and soil temperatures, suggesting that an increasing canopy cover promotes snow accumulation and, hence, a more favorable microclimate. (iii) Tree age analysis showed that forest expansion mainly began around the year 1900 on concave wind‐sheltered slopes with thick snow covers, while it started in the 1950s and 1970s on slopes with shallower snow covers. (iv) During the 20th century, dominant growth forms of trees have changed from multistemmed trees, resulting from harsh winter conditions, to single‐stemmed trees. While 87%, 31%, and 93% of stems appearing before 1950 were from multistemmed trees in the South, North and Polar Urals, more than 95% of the younger trees had a single stem. Currently, there is a high density of seedlings and saplings in the forest‐tundra ecotone, indicating that forest expansion is ongoing and that alpine tundra vegetation will disappear from most mountains of the South and North Urals where treeline is already close to the highest peaks.     

Biochemical analysis of neutral endopeptidase activity reveals independent catabolism of atrial and brain natriuretic peptide

Recent reports presented contradictory results regarding the catabolism of mature atrial (ANP) and brain (BNP) natriuretic peptides in circulation. Especially the role of neutral endopeptidase (NEP) in BNP degradation was conversely discussed. Our present in vitro-studies characterize the NEP-dependent metabolism of ANP and BNP in different tissues via HPLC-analysis using NEP-deficient mice and specific NEP inhibitors. Our results show a strong tissue-dependent degradation pattern of both peptides, which are not only due to the different NEP activities in these tissues. Whereas NEP rapidly degraded ANP, it had no influence in BNP-metabolism. Additional experiments with purified NEP confirmed this result. Moreover, we describe a degradation of ANP and BNP in NEP-deficient- and NEP-inhibited membranes. Consequently, we postulate the existence of at least one further natriuretic peptide (NP) degrading enzyme, which has not been characterized yet. Thus, the commonly accepted model of the natriuretic peptide system with NEP as the central degrading peptidase has to be partly revised. Moreover, the NEP-independent BNP degradation provides an effective means for achieving a beneficial BNP increase in cardiovascular pathology by inhibiting the assumed novel NP-degrading peptidase(s).     

Microdissection and sequence analysis of pericentric heterochromatin from the Drosophila melanogastermutant Suppressor of Underreplication

In the Suppressor of Underreplication( SuUR) mutant strain of Drosophila melanogaster, the heterochromatin of polytene chromosomes is not underreplicated and, as a consequence, a number of beta-heterochromatic regions acquire a banded structure. The chromocenter does not form in these polytene chromosomes, and heterochromatic regions, normally part of the chromocenter, become accessible to cytological analysis. We generated four genomic DNA libraries from specific heterochromatic regions by microdissection of polytene chromosomes. In situ hybridization of individual libraries onto SuUR polytene chromosomes shows that repetitive DNA sequences spread into the neighboring euchromatic regions. This observation allows the localization of eu-heterochromatin transition zones on polytene chromosomes. We find that genomic scaffolds from the eu-heterochromatin transition zones are enriched in repetitive DNA sequences homologous to those flanking the suppressor of forked gene [ su(f) repeat]. We isolated and sequenced about 300 clones from the heterochromatic DNA libraries obtained. Most of the clones contain repetitive DNA sequences; however, some of the clones have unique DNA sequences shared with parts of unmapped genomic scaffolds. Hybridization of these clones onto SuUR polytene chromosomes allowed us to assign the cytological localizations of the corresponding genomic scaffolds within heterochromatin. Our results demonstrate that the SuUR mutant renders possible the mapping of heterochromatic scaffolds on polytene chromosomes.