The Extent of Left Atrial Low-Voltage Areas Included in Pulmonary Vein Isolation Is Associated With Freedom from Recurrent Atrial Arrhythmia

Background

The extent of left atrial (LA) baseline low-voltage areas (LVA-B), which may be a surrogate for fibrosis, is associated with recurrent atrial fibrillation (AF) after ablation. This study aimed to assess the relationship between the extent of LVA-B isolated by ablation (LVA-I) and AF recurrence.

Does gender affect human pulmonary gas exchange during exercise?

Fetal growth depends on the transplacental nutrient supply, which, in turn, is determined partially by the consumption and production of nutrients by the uteroplacental tissues. In fetal sheep, the rates of growth and umbilical glucose uptake decline coincidently towards term in parallel with the normal prepartum rise in plasma cortisol. While cortisol is known to reduce growth in fetal sheep, its effects on the uteroplacental handling and delivery of nutrients remain unknown. Hence, this study, quantified the rates of umbilical uptake and uteroplacental consumption of nutrients in preterm fetuses infused with cortisol for 5 days to mimic the prepartum cortisol surge. Umbilical uptakes of glucose and lactate, but not oxygen, were significantly lower in cortisol- than saline-infused fetuses, irrespective of whether values were expressed as absolute or weight-specific rates. The rate of uteroplacental consumption of glucose, but not oxygen, was significantly higher in cortisol- than saline-infused animals. Absolute rates of uteroplacental lactate production were lower in cortisol-infused animals. When all data were combined, fetal plasma cortisol levels were positively correlated to uteroplacental glucose consumption and inversely related to umbilical glucose uptake. Cortisol treatment had no apparent effect on placental mRNA expression for the glucose transporters, GLUT-1 and GLUT-3. The results demonstrate that cortisol is physiological regulator of uteroplacental metabolism and nutrient delivery to the sheep fetus. These observations have important implications for fetal growth both in late gestation and during adverse intrauterine conditions, which raise fetal cortisol levels earlier in gestation.     

Intra-Atrial Dyssynchrony During Sinus Rhythm Predicts Recurrence After the First Catheter Ablation for Atrial Fibrillation

Objectives

The purpose of this study was to evaluate the usefulness of intra-atrial dyssynchrony as a marker of underlying left atrial (LA) remodeling to predict recurrence after the first atrial fibrillation (AF) ablation.

Influence of channel height on mixing efficiency and synthesis of iron oxide nanoparticles using droplet-based microfluidics

Microfluidic devices, allowing superior control over the spatial and temporal distribution of chemical substances and high process reproducibility, are nowadays essential in various research areas and industrial fields where the traditional “macroscopic” approach was no longer able to keep up with the increasing demands of high-end applications. In the present work, internal mixing of droplets formed by a flow-focusing X-junction at constant flow rates of both phases for three different channel heights (i.e. 20, 40 and 60 μm) was investigated and characterised. Both experimental methods and 3D CFD simulations were employed in order to resolve governing factors having an impact on internal mixing and homogenization time of model tracers inside of droplet reactors. Additionally, the influence of channel height on internal mixing was experimentally studied for continuous preparation of iron oxide nanoparticles by co-precipitation reaction. Since the initial nucleation phase is strongly affected by mixing and spatial distribution of all reactants, the final particle size and particle size distribution (PSD) can be used as direct indicators of mixing performance. It has been demonstrated that the smallest 20 μm channels provided narrower PSD and smaller particle mean size compared to higher channels.

Experimental and CFD numerical analysis of mixing efficiency in droplet-based microfluidics for various channel heights and its impact on the preparation of iron oxide nanoparticles.     

Oral manifestation of Crohn’s disease without concomitant gastrointestinal involvement

Crohn’s disease (CD) is a chronic relapsing inflammatory disorder of unknown etiology and uncertain pathogenesis with no known cure. CD can involve any segment of the gastrointestinal tract, and oral lesions consistent with granulomatous ulcers are considered an important extra-intestinal manifestation. Oral lesions in the absence of gastrointestinal involvement are rarely reported. We report a case of a 64-year-old man with a history of CD that was in remission for three decades, presenting with painful cobblestone-like ulcerations of the oral mucosa, but without gastrointestinal signs or symptoms. Surgical biopsy of the oral lesions revealed non-necrotizing chronic granulomatous ulcers on histopathologic examination, similar to results from a biopsy of his small intestine three decades previously which established his diagnosis of CD. The patient was successfully treated with potent topical corticosteroids which resulted in resolution of the oral lesions and associated symptoms.     

Statut magnésique dans une population marocaine de patients diabétiques de type 2

Blood and urinary samples from 121 patients with type 2 diabetes mellitus and 51 healthy controls, were analysed for blood glucose, glycosylated Haemoglobin, total cholesterol and its fractions, triglycerides, serum creatinine, microalbuminuia, magnesium (plasma, erythrocyte and urinary).Diabetic patients had significantly lower plasma and erythrocyte magnesium comparatively to healthy control (P Mg: 0.83±0.09 mmol/L vs 0.90±0.06 mmol/L, P<0.001) (E Mg : 1.42±0.64 mmol/L vs 2.01±0.6 ; P<0.001). whereas the urinary magnesium excretion in diabetic patients and control group is not significantly different (U Mg : 6,47±3 mmol/24 heures vs 6,82±2,44 mmol/24 heures, P=0,48).Plasma and erythrocyte magnesium in diabetic patients was negatively correlated with glucose blood, and HbA1c (P Mg vs HbA1c: P=0,016, r =−0,22), (E Mg vs HbA1c : P=0,012, r =−0,23), whereas there is no correlation with lipids parameters.We also note that plasma magnesium concentrations are lower in diabetic patients with retinopathy compared to those without retinopathy (0,80±0,10 mmol/L vs 0.84±0,08; P=0.035).Conclusion: Magnesium depletion is most common in our population, particularly in uncontrolled diabetic patients, with a weakly significant relationship with diabetic retinopathy.     

The effect of incomplete acetylene washout on cardiac output measurement using open circuit acetylene uptake

The open circuit acetylene uptake method is a useful non-invasive means of measuring cardiac output. However, because of accumulation of inhaled acetylene in tissues, the cardiac output uptake is underestimated, if residual acetylene is not allowed to wash out completely in between measurements. We determined the effect of applying a correction factor that estimates mixed venous acetylene concentration from endtidal values to the calculation of cardiac output. This accounts for mixed venous acetylene present during measurements made before complete washout. Six healthy subjects performed steady-state exercise at approximately 30% and 60% of V(O2 max). Cardiac output measurements were made at each exercise intensity using the open circuit acetylene uptake method (inspired [acetylene] approximately 1%), with the first and last measurements having no detectible levels of acetylene in expired gas (reference measurement). Data were also obtained with immediate pre-measurement endtidal concentrations ranging from 3% to 15% of the inspired [acetylene], in random order in between. Oxygen consumption, carbon dioxide production and heart rate did not change significantly during testing at each exercise intensity. Reference cardiac output also did not change significantly and averaged 11.1+/-0.8 L/min at 30% of V(O2 max) and 16.5+/-2.0 L/min at 60% of V(O2 max). Uncorrected cardiac output measurements progressively underestimated cardiac output by 15% at the 3% of inspired endtidal [acetylene] and by over 50% at 15% [acetylene] (p<0.0001). However, when corrected for residual endtidal [acetylene], cardiac outputs were not significantly different from the reference measurements. The results of this study suggest that by accounting for residual endtidal acetylene in mixed venous blood, cardiac output can be accurately measured even when washout of acetylene is incomplete, allowing measurements as often as every 10-15 s.