Predictors of long-term atrial fibrillation recurrence after catheter ablation: non-linear analytical approach for individualized prognostic stratification

Background

Recurrences are common in patients with atrial fibrillation (AF) during long-term follow-up after catheter ablation (CA) for pulmonary vein isolation (PVI). Recently, machine learning (ML) models identifying non-linear relationships among various patient parameters have been applied for prognostic stratification in different cardiac diseases.

Aim

This is a retrospective study aimed to determine whether ML-based models can identify non-linear relationships in individual clinical baseline characteristics and CT-quantified volumetric parameters of epicardial fat tissue (EFT) to aid in prognosing outcome of catheter ablation for PVI in patients with paroxysmal AF.

Methods

A cohort of 92 patients (median age 60.2 [51.9–64.0]; 74% male) with paroxysmal AF (a single persistent AF episode was accepted) undergoing catheter ablation targeting PVI was analysed. All patients underwent cardiac CT imaging and were fitted with implantable loop recorder (ILR) prior to CA. For PVI, radiofrequency CA with electro-anatomical mapping was used in 79 patients, cryoballoon ablation in 13 patients. AF recurrence, defined as AF burden >0.1% after the blanking period (90 days), was continuously assessed by ILR. Feature selection on 23 baseline parameters was performed using random forest models (XGBoostRegressor). Mean absolute Shapley values (|mSHAP| – Shapley Additive expLanations) were used to quantify the relative discriminative power of analysed parameters.

Results

During a follow-up of 3-years, AF recurrence was detected in 58 (63%) patients, 29 (50%) of them underwent a repeat ablation. Five most important predictors of AF recurrence during 3-year follow-up were upper epicardial fat volume, BMI, baseline AF burden, age and pericardial volume (lower segment) (Fig. 1). Upper EFT volume was twice as important for males than females (0.44 and 0.21 |mSHAP| respectively). For a patient with no AF recurrence, low age (41 years) and low upper EFT volume (13.2 ml) were the most important drivers predicting positive ablation outcome (Fig. 2A). In contrast, in a patient with AF recurrence post CA, an above-average EFT volume of 55.5 ml and a high BMI had the most significant net contribution for predicting his failed CA outcome (Fig. 2B).

Conclusion

Non-linear ML analysis applied to our limited cohort of patients with paroxysmal AF undergoing CA suggests: i) a significant association of high EFT volume with ILR determined AF recurrence during a 3-year follow-up; ii) potential role of such analyses for a more granular and highly individualized prediction of outcome of planned CA. However, these results need further testing, and validation in prospective trials.

Funding Acknowledgement

Type of funding sources: None.

High epicardial fat volume is associated with atrial fibrillation recurrences after catheter ablation

Background

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation therapy for atrial fibrillation (AF). However, even with important technological improvements, AF recurrences are common in long-term follow-up. Recently, epicardial fat tissue (EFT) has been proposed as a potential AF modulator promoting and sustaining atrial arrhythmogenic milieu.

Aim

In this retrospective single-centre study, we sought to evaluate the association between CT-quantified EFT volume and long-term primary PVI outcome assed by means of continuous ECG monitoring with implantable loop recorders (ILR) in paroxysmal AF patients.

Methods

A cohort of 92 patients (median age 60.2 [IQR 51.9–64.0]; 74% male) with paroxysmal AF (a single persistent AF episode was accepted) undergoing catheter ablation targeted at PVI was analysed. Prior to CA all patients underwent cardiac CT imaging with subsequent implantation of implantable loop recorder (ILR). Radiofrequency CA ablation with electro-anatomical mapping for PVI was used in 79 patients, balloon cryoablation was used in 13 patients. Verified complete PVI was defined as procedural endpoint. EFT volume was semi-automatically segmented and quantified on contrast enhanced CT studies. AF recurrence, defined as AF burden >0.1% after the blanking period (90 days), was continuously assessed by ILR. Kaplan-Meier analysis of AF recurrence-free survival at 1-year, 2-year and 3-year follow-up periods compared patients stratified into EFT volume tertiles.

Results

During a median follow-up of 52.6 months [IQR 43–64], AF recurrence was detected in 58 (63%) patients, 29 (50%) of them underwent a repeat ablation. Patients in high, mid, and low total EFT volume tertiles had a median time to late AF recurrence of 154, 373, and 284 days (Fig. 1A). At a 1-year follow-up, patients in the high EFT volume tertile had the worst AF ablation outcome (p=0.023). However, this difference gradually faded-out and became non-significant at 2 and 3 years. ROC analysis revealed an EFT of 95 ml as an optimal cut-off (p=0.002) for expected arrhythmia recurrence post acutely successful PVI (Fig. 1B).

Conclusion

EFT volume quantification in a relatively homogenous, continuously monitored cohort of patients undergoing catheter ablation for paroxysmal AF revealed a significant association between AF recurrence at 1 year post ablation and volume of epicardial fat. These results suggest a possible role of epicardial adipose tissue as an adverse pro-fibrillatory factor. Identified EFT volume cut-offs have to be validated prospectively on a larger and balanced patient population.

Funding Acknowledgement

Type of funding sources: None.

Genistein does not inhibit TGF-beta1-induced conversion of human dermal fibroblasts to myofibroblasts

Transforming growth factor beta 1 (TGF-beta1) is a pro-fibrotic cytokine with a key role in wound repair and regeneration, including induction of fibroblast-to-myofibroblast transition. Genistein is a naturally occurring selective estrogen receptor modulator with promising anti-fibrotic properties. In the present study we aimed to investigate whether genistein modulates TGF-beta1 (canonical and non-canonical) signaling in normal dermal fibroblasts at the protein level (Western blot and immunofluorescence). We demonstrated that TGF-beta1 induces the myofibroblast-like phenotype in the studied fibroblast signaling via canonical (SMAD) and non-canonical (AKT, ERK1/2, ROCK) pathways. Genistein induced only ERK1/2 expression, whereas the combination of TGF-beta1 and genistein attenuated the ERK1/2 and ROCK signaling. Of note, the other studied pathways remained almost unaffected. From this point of view, genistein does not impair conversion of normal fibroblasts to myofibroblast-like cells.

Concentration of apelin inversely correlates with atrial fibrillation burden

AIM

Asymptomatic atrial fibrillation (AF) detection and pulmonary veins isolation (PVI) outcome prediction remain challenging. Our aim was to study the association between apelin and paroxysmal AF in patients undergoing radiofrequency catheter PVI.

METHODS

Sixty-three consecutive patients (55 ± 8years, 12 females) with paroxysmal AF without a structural heart disease and implanted ECG loop recorders undergoing PVI and healthy control group of 34 persons (41 ± 9.5years, 21 females) were included. Apelin plasmatic concentrations were measured before and three months after PVI. AF burden was continually assessed for three years.

RESULTS

Apelin was significantly decreased in AF patients compared to the healthy controls (0.79 ± 0.09 vs 0.98 ± 0.06 ng/ml; p < 0.00001). Apelin plasmatic concentration of 0.89 ng/ml had 94 % specificity and 89 % sensitivity for AF prediction with the area under the curve (AUC) of 0.96. After propensity matching to sex, age and comorbidities, apelin concentration was significantly lower in AF group (0.78 ± 0.1 vs 0.99 ±0.06  ng/ml; p < 0.0001; AUC: 0.97). There was a significant inverse correlation between apelin concentration and AF burden both before and after PVI (Rho = ‒0.22; p = 0.05) and (Rho = ‒0.51; p = 0.006), respectively. There was no significant association between pre-PVI apelin and PVI long-term outcome.

CONCLUSION

In patients without a structural heart disease apelin showed a significant specificity and sensitivity for AF prediction and inversely correlated with AF burden (Tab. 3, Fig. 3, Ref. 34).

A scaled explicitly correlated F12 correction to second-order Møller-Plesset perturbation theory

An empirically scaled version of the explicitly correlated F12 correction to second-order Møller-Plesset perturbation theory (MP2-F12) is introduced. The scaling eliminates the need for many of the most costly terms of the F12 correction while reproducing the unscaled explicitly correlated F12 interaction energy correction to a high degree of accuracy. The method requires a single, basis set dependent scaling factor that is determined by fitting to a set of test molecules. We present factors for the cc-pVXZ-F12 (X = D, T, Q) basis set family obtained by minimizing interaction energies of the S66 set of small- to medium-sized molecular complexes and show that our new method can be applied to accurately describe a wide range of systems. Remarkably good explicitly correlated corrections to the interaction energy are obtained for the S22 and L7 test sets, with mean percentage errors for the double-zeta basis of 0.60% for the F12 correction to the interaction energy, 0.05% for the total electron correlation interaction energy, and 0.03% for the total interaction energy, respectively. Additionally, mean interaction energy errors introduced by our new approach are below 0.01 kcal mol^-1 for each test set and are thus negligible for second-order perturbation theory based methods. The efficiency of the new method compared to the unscaled F12 correction is shown for all considered systems, with distinct speedups for medium- to large-sized structures.

Impact of UV-C Radiation Applied during Plant Growth on Pre- and Postharvest Disease Sensitivity and Fruit Quality of Strawberry

Ultraviolet-C (UV-C) radiation is efficient in reducing the development of diseases in many species, including strawberry (Fragaria × ananassa). Several studies suggest that UV-C radiation is effective not only because of its disinfecting effect but also because it may stimulate plant defenses. In this study, the effect of preharvest UV-C radiation applied during strawberry cultivation on plant growth, fruit quality, and susceptibility to major fungal diseases such as gray mold, powdery mildew, and soft rot was evaluated. UV-C treatments had an impact on flowering initiation and fruit development. Flowering occurred earlier for UV-C-treated plants than for nontreated plants. At harvest, a larger amount of fruit was produced by treated plants despite their slight decrease in leaf area. UV-C treatment did not improve strawberry shelf life but did not alter the physical integrity of strawberry fruit. Natural infection of leaves to powdery mildew and of fruit to Rhizopus spp. strongly decreased in response to UV-C treatment.

Eosinophilic granulomatosis with polyangiitis, a new recurrent feature in an extremely rare disease

Introduction

Eosinophilic granulomatosis with polyangiitis (EGPA) is an extremely rare necrotizing vasculitis affecting small- and medium-sized vessels. EGPA may affect the heart leading to myocardial inflammation and necrosis. Although, only a few cardiological based studies have been conducted.

Purpose

This study aimed to investigate the prevalence and clinical impact of cardiac-specific involvement (CSI+) and to give an update on EGPA cardiological manifestations.

Methods

This is a single-centre study. Cardiological evaluation included ECG, blood test, echocardiography, global longitudinal strain (GLS), cardiac magnetic resonance (CMR).

Results

We prospectively enrolled 52 consecutive EGPA patients, between October 2018 and October 2019, mean age 59±3 years, 30 (57%) female. We identified 13 (25%) CSI+ patients: 6 myocarditis, 2 pericarditis, 1 coronaritis, 1 Prinzmetal angina, 2 LV apical thrombosis, 1 unexplained wall motions abnormalities (WMA) in the absence of coronary artery disease.

Twelve-leads ECG revealed abnormalities in 11 (85%) CSI+ vs 9 (23%) CSI−, p=0.0001; ECG abnormalities identified CSI+ with 85% sensitivity, 77% specificity, 94% negative predictive value.

Median troponin level in CSI+ 9 ng/L (IQR 6–11) vs CSI− 11 ng/L (IQR 6–25), p=0.2548; NT-pro-BNP value in CSI+ 210 pg/L (IQR 175–484) vs CSI− 159 ng/L (IQR 66–299), p=0.0576.

Echocardiographic left ventricular end diastolic volume in CSI+ 62±4 ml/m2 vs CSI− 52±1 ml/m2, p=0.0116; LV ejection fraction in CSI+ 57%±2 vs CSI− 66%±1, p=0.0002. In CSI+ patients GLS was −15±1 vs CSI− GLS −21±0.4, p&lt;0.0001. Echocardiography identified WMA in 8 (61%) CSI+ vs 1 (3%) CSI−. In 7 (54%) CSI+ patients, apical segments showed WMA and among them 5 demonstrated the presence of apical aneurysm.

Twelve patients underwent CMR, it showed non ischaemic late gadolinium enhancement in 7 patients; in 5 patients we identified akinetic or dyskinetic segments without associated LGE. Two patients showed LV apical thrombus.

Conclusions

EGPA showed a high prevalence of CSI. We repeatedly found a tropism for apical involvement in WMA that often manifested themselves as apical aneurysm. These may be a new clinical feature, previously not described, in such a rare condition.

Cardiac involvement EGPA

Funding Acknowledgement

Type of funding source: None

Association of apelin and AF in patients with implanted loop recorders undergoing catheter ablation

BACKGROUND

Previous studies showed an association between apelin and atrial fibrillation (AF). The aim of this study was to analyse the effect of pulmonary vein isolation (PVI) in patients with paroxysmal AF on plasmatic apelin concentrations.

METHODS

Nine consecutive patients (aged from 43 to 69 years, 3 females and 6 males) with documented paroxysmal atrial fibrillation and implanted loop recorders (ILR) for continuous ECG monitoring were included in this study. All the patients underwent a radiofrequency catheter ablation with PVI.

RESULTS

The plasmatic concentration of apelin increased after PVI. The average plasmatic concentration of apelin before PVI was 0.299 ng/ml (±0.16), 3 months after PVI 0.462 ng/ml (±0.10) and 9 months after PVI 0.565 ng/ml (±0.146). There was an increase in the concentration of apelin 3 months and 9 months after the PVI by 0.163 ng/ml (p=0.07) and by 0.266 ng/ml (p=0.01), respectively. The concentration of apelin inversely correlated with the AF burden (r=-0.44, p=0.03).

CONCLUSIONS

Our study showed a significant increase in apelin levels after the reduction of AF burden via PVI and an inverse correlation with AF burden. Apelin might be a promising marker of AF (Tab. 2, Fig. 2, Ref. 28).

Adapting detection sensitivity based on evidence of irregular sinus arrhythmia to improve atrial fibrillation detection in insertable cardiac monitors

Aims

Intermittent change in p-wave discernibility during periods of ectopy and sinus arrhythmia is a cause of inappropriate atrial fibrillation (AF) detection in insertable cardiac monitors (ICM). To address this, we developed and validated an enhanced AF detection algorithm.

Methods and results

Atrial fibrillation detection in Reveal LINQ ICM uses patterns of incoherence in RR intervals and absence of P-wave evidence over a 2-min period. The enhanced algorithm includes P-wave evidence during RR irregularity as evidence of sinus arrhythmia or ectopy to adaptively optimize sensitivity for AF detection. The algorithm was developed and validated using Holter data from the XPECT and LINQ Usability studies which collected surface electrocardiogram (ECG) and continuous ICM ECG over a 24–48 h period. The algorithm detections were compared with Holter annotations, performed by multiple reviewers, to compute episode and duration detection performance. The validation dataset comprised of 3187 h of valid Holter and LINQ recordings from 138 patients, with true AF in 37 patients yielding 108 true AF episodes ≥2-min and 449 h of AF. The enhanced algorithm reduced inappropriately detected episodes by 49% and duration by 66% with <1% loss in true episodes or duration. The algorithm correctly identified 98.9% of total AF duration and 99.8% of total sinus or non-AF rhythm duration. The algorithm detected 97.2% (99.7% per-patient average) of all AF episodes ≥2-min, and 84.9% (95.3% per-patient average) of detected episodes involved AF.

Conclusion

An enhancement that adapts sensitivity for AF detection reduced inappropriately detected episodes and duration with minimal reduction in sensitivity.

Telocytes (interstitial Cajal-like cells) in human Fallopian tubes

BACKGROUND

Telocytes represent a relatively newly discovered population of cells found within the various tissues and organs, including Fallopian tubes. It is presumed that telocytes could serve as a sensor of hormone levels or regulate activity of muscle peristaltic movement.

METHODS

Tissue sections from anatomically different parts of Fallopian tubes of 48 women (age 48.8±9.1) were stained for the expression of five different antigens: c-kit (CD117), CD34, vimentin, podoplanin (D2-40) and Dog-1.

RESULTS

Telocytes form a network associated with the smooth muscle cells. From the mentioned antibodies, only anti-c-kit (CD117) seems to be relatively selective specific to the telocytes, others react also with numerous other cells and tissue structures. Our results when using antibodies against podoplanin and Dog-1 are in dissonance with recent literature - with regards to our results, they are not suitable for detection of telocytes.

CONCLUSION

Methods of immunohistochemistry are suitable for identification of telocytes in Fallopian tubes. C-kit (CD117) antigens are useful for routine identification of telocytes in histological sections. This antigen can be combined with CD34 or vimentin in cases of double staining immunohistochemistry.

The relation between oxidative stress biomarkers and atrial fibrillation after pulmonary veins isolation

INTRODUCTION

The current paradigm claims a link between oxidative stress and atrial fibrillation. The aim of our research was to study a relation between the percentage of time spent in atrial fibrillation (AF burden) and concentrations of oxidative stress biomarkers, before and after pulmonary veins isolation (PVI).

METHODOLOGY

We included 19 patients (mean age 55±10years, 4 females and 15 males) with implanted loop recorders undergoing PVI. Plasmatic concentrations of advanced glycation end-products (AGEs), fructosamine, advanced oxidation protein products and thiobarbituric-acid reacting substances (TBARS) were measured and AF burden was recorded immediately before and 3months after the PVI. AF burden was also recorded 9months after the PVI.

RESULTS

Post procedural AGEs concentration significantly negatively correlated with AF burden after 3months (ρ=-0.63; p<0.01) and 9months (ρ=-0.5; p=0.04), respectively as well as TBARS concentration significantly negatively correlated with AF burden after 9months (ρ=-0.61; p=0.01).

CONCLUSION

Our study showed AGEs and TBARS to be potential predictors for AF burden after the PVI. We suppose that the more oxidative stress after the PVI is provoked, the more fibrotic tissue is produced. That means a better electrical isolation of pulmonary veins and consequently a lower AF burden.

[Functional morphology of recently discovered telocytes inside the female reproductive system]

Discovery of telocytes has become an important and key challenge in past few years. These cells are interstitial cells extending very long cytoplasmic processes named telopodes, by which they create functional networks in the interstitium of different organs. Telocytes are considered to be connective tissue elements that create contacts among each other, but they also function as intercellular structures, functionally connected with cells of the immune system, neurons and smooth muscle cells. Telocytes can be found also in the different parts of female reproductive system with functions and purpose, which is summarized in our overview. Telocytes regulate for example peristaltic movements in fallopian tubes. The decrease of their number (due to inflammatory disease or endometriosis) causes impairment in transport through fallopian tubes which may result in sterility or tubal gravidity. In uterus they regulate contraction of myometrial smooth muscle (blood expulsion in menstrual phase, childbirth) as well as they contribute in immunological care during embryo implantation. Telocytes probably control also the involution of uterus after delivery. Their function in vagina has not been yet clearly defined; they probably take part in slow muscle contraction movement during sexual intercourse. In mammary glands some scientists suppose their function in control of cell proliferation and apoptosis, that is why, they may play a role in carcinogenesis. In placenta they probably monitor and regulate flow of blood in vessels of chorionic villi and they may be responsible also for etiopathogenesis of pre-eclampsy. All these mentioned functions of telocytes are only in the level of hypothesis and have been published recently. New research and studies will try to answer the questions whether telocytes play a key role in these processes. Our review we completed with some original microphotographs of telocytes in different organs of female reproductive system.

Detection of occult paroxysmal atrial fibrilation by implantable long-term electrocardiographic monitoring in cryptogenic stroke and transient ischemic attack population: a study protocol for prospective matched cohort study

BACKGROUND

Cardio-embolic etiology is the most frequently predicted cause of cryptogenic stroke/TIA. Detection of occult paroxysmal atrial fibrillation is crucial for selection of appropriate medication.

METHODS

Enrolment of eligible cryptogenic stroke and TIA patients began in 2014 and will continue until 2018. The patients undergo long-term (12 months) ECG monitoring (implantable loop recorder) and testing for PITX2 (chromosome 4q25) and ZFHX3 (chromosome 16q22) gene mutations. There will be an appropriate control group of age- and sex-matched healthy volunteers. To analyse the results descriptive statistics, statistical tests for group differences, and correlation analyses will be used.

DISCUSSION

In our study we are focusing on a possible correlation between detection of atrial fibrillation by an implantable ECG recorder, and PITX2 and/or ZFHX3 gene mutations in cryptogenic stroke/TIA patients. A correlation could lead to implementation of this genomic approach to cryptogenic stroke/TIA diagnostics and management. The results will be published in 2018.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02216370 .

Transient receptor potential ion channels in primary sensory neurons as targets for novel analgesics

The last decade has witnessed an explosion in novel findings relating to the molecules involved in mediating the sensation of pain in humans. Transient receptor potential (TRP) ion channels emerged as the greatest group of molecules involved in the transduction of various physical stimuli into neuronal signals in primary sensory neurons, as well as, in the development of pain. Here, we review the role of TRP ion channels in primary sensory neurons in the development of pain associated with peripheral pathologies and possible strategies to translate preclinical data into the development of effective new analgesics. Based on available evidence, we argue that nociception-related TRP channels on primary sensory neurons provide highly valuable targets for the development of novel analgesics and that, in order to reduce possible undesirable side effects, novel analgesics should prevent the translocation from the cytoplasm to the cell membrane and the sensitization of the channels rather than blocking the channel pore or binding sites for exogenous or endogenous activators.

[New views on the functional morphology of human clitoris]

The clitoris is the female external sexual organ and is composed of erectile bodies. The distal portion of the vagina, clitoris and urethra form an integrated entity sui generis. All these components share a common vasculature and nerve supply and during sexual stimulation they respond as one functional unit. The clitoris is closely linked to the mechanism of sexual arousal in women. Glans has a dense network of receptors, innervated often with a several nerves at the same time - taking care of tactile sensitivity, thus, standing on the beginning of the journey, which culminates in orgasm. Nervus dorsalis clitoridis, which is a branch of n. pudendus, takes care of sensitive innervation. For blood supply is responsible a. clitoridis, which is a branch of a. pudenda interna. The most common congenital developmental anomalies of the clitoris include: clitoromegaly, penis-like clitoris and bifid clitoris. All, however, are among the relatively rare birth defects. Mechanism of orgasm gets attention between both laic and scientific community, although to this date there are speculations about its exact mechanism. There is relevant opinion, influenced by Freuds doctrine, which strictly recognizes two kinds of female orgasms - vaginal and clitoral, and, according to proponents of this theory, only the second mentioned is caused by stimulation of the clitoris. The second school unifies the term orgasm and claims that only clitoral stimulation (digital, penile, cunnilingus) and contraction of striated perineal muscle are responsible for orgasm, whether the glans (external part) or the body of the clitoris from the vaginal approach is stimulated. Therewithal, special term for mythical and still undocumented (despite many attempts and bold claims about its finding) G spot (named after Ernst Gräfenberg, a German doctor who predicted the existence of this place) is redundant. Important role in the regulation of female sexuality and responsiveness play a hormonal influences and varying concentrations of neurotransmitters.

Carotenoid responses to environmental stimuli: integrating redox and carbon controls into a fruit model

Carotenoids play an important role in plant adaptation to fluctuating environments as well as in the human diet by contributing to the prevention of chronic diseases. Insights have been gained recently into the way individual factors, genetic, environmental or developmental, control the carotenoid biosynthetic pathway at the molecular level. The identification of the rate-limiting steps of carotenogenesis has paved the way for programmes of breeding, and metabolic engineering, aimed at increasing the concentration of carotenoids in different crop species. However, the complexity that arises from the interactions between the different factors as well as from the coordination between organs remains poorly understood. This review focuses on recent advances in carotenoid responses to environmental stimuli and discusses how the interactions between the modulation factors and between organs affect carotenoid build-up. We develop the idea that reactive oxygen species/redox status and sugars/carbon status can be considered as integrated factors that account for most effects of the major environmental factors influencing carotenoid biosynthesis. The discussion highlights the concept of carotenoids or carotenoid-derivatives as stress signals that may be involved in feedback controls. We propose a conceptual model of the effects of environmental and developmental factors on carotenoid build-up in fruits.

Hydrogen bonding of nitroxide spin labels in membrane proteins

On the basis of experiments at 275 GHz, we reconsider the dependence of the continuous-wave EPR spectra of nitroxide spin-labeled protein sites in sensory- and bacteriorhodopsin on the micro-environment.

Design and performance of an ultra-high vacuum scanning tunneling microscope operating at dilution refrigerator temperatures and high magnetic fields

We describe the construction and performance of a scanning tunneling microscope capable of taking maps of the tunneling density of states with sub-atomic spatial resolution at dilution refrigerator temperatures and high (14 T) magnetic fields. The fully ultra-high vacuum system features visual access to a two-sample microscope stage at the end of a bottom-loading dilution refrigerator, which facilitates the transfer of in situ prepared tips and samples. The two-sample stage enables location of the best area of the sample under study and extends the experiment lifetime. The successful thermal anchoring of the microscope, described in detail, is confirmed through a base temperature reading of 20 mK, along with a measured electron temperature of 250 mK. Atomically resolved images, along with complementary vibration measurements, are presented to confirm the effectiveness of the vibration isolation scheme in this instrument. Finally, we demonstrate that the microscope is capable of the same level of performance as typical machines with more modest refrigeration by measuring spectroscopic maps at base temperature both at zero field and in an applied magnetic field.

[Effects of dose of erythropoiesis stimulating agents on cardiovascular outcomes, quality of life and costs of haemodialysis. the clinical evaluation of the DOSe of erythropoietins (C.E. DOSE) Trial]

BACKGROUND

Anaemia is a risk factor for death, adverse cardiovascular outcomes and poor quality of life in patients with chronic kidney disease (CKD). Erythropoietin Stimulating Agents (ESA) are the most used treatment option. In observational studies, higher haemoglobin (Hb) levels (around 11-13 g/dL) are associated with improved survival and quality of life compared to Hb levels around 9-10 g/dL. Randomized studies found that targeting higher Hb levels with ESA causes an increased risk of death, mainly due to adverse cardiovascular outcomes. It is possible that this is mediated by ESA dose rather than haemoglobin concentration, although this hypothesis has never been formally tested.

METHODS

We present the protocol of the Clinical Evaluation of the Dose of Erythropoietins (C.E. DOSE) trial, which will assess the benefits and harms of a high versus a low ESA dose therapeutic strategy for the management of anaemia of end stage kidney disease (ESKD). This is a randomized, prospective open label blinded end-point (PROBE) design trial due to enroll 900 haemodialysis patients. Patients will be randomized 1:1 to 4000 UI/week i. v. versus 18000 UI/week i. v. of epoetin alfa, beta or any other epoetin in equivalent doses. The primary outcome of the trial is a composite of cardiovascular events. In addition, quality of life and costs of these two strategies will be assessed. The study has been approved and funded by the Italian Agency of Drugs (Agenzia Italiana del Farmaco (AIFA)) within the 2006 funding plan for independent research on drugs (registered at www.clinicaltrials.gov (NCT00827021)).

Measurements of the magnetic-field-tuned conductivity of disordered two-dimensional Mo43Ge57 and InOx superconducting films: evidence for a universal minimum superfluid response

Our measurements of the low frequency ac conductivity in strongly disordered two-dimensional films near the magnetic-field-tuned superconductor-to-insulator transition show a sudden drop in the phase stiffness of superconducting order with either increased temperature or magnetic field. Surprisingly, for two different material systems, the abrupt drop in the superfluid density in a magnetic field has the same universal value as that expected for a Berezinskii-Kosterlitz-Thouless transition in a zero magnetic field. The characteristic temperature at which phase stiffness is suddenly lost can be tuned to zero at a critical magnetic field, following a power-law behavior with a critical exponent consistent with that obtained in previous dc transport studies on the dissipative side of the transition.

[The structural basis for transport through the Fallopian tube]

The Fallopian tube has until recently been a neglected structure, bypassed by in vitro fertilization and seen only as a tube that transports the oocyte or early embryo to the uterus. More recently, its role is even more undervalued after the introduction of techniques of assisted reproduction, in which the Fallopian tubes become like unnecessary. The Fallopian tube performs several important functions. It captures the oocyte after ovulation, maintains and controls the migration of spermatozoa to the site of fertilization. It provides the special microenvironment for fertilization; nourishes the early embryo while it is being carried to the uterus and amplifies signals from embryo to the mother. In our article we conducted a systematic review of relevant articles found in PubMed, Scopus and ISI Web of Knowledge, focused on the new insights into the functional morphology of Fallopian tube. We described the possible function of muscle layer motility, ciliary activity and tubal fluid movement on transport of gamets / embryo, as well as we mentioned the negative factors (such as smoking, chlamydial infection or endometriosis) affecting the transport through the Fallopian tube.

Long-term cardiac effects of treatment for childhood leukemia

Late cardiac complications in cancer survivors may develop from subclinical myocardial damage. Biochemical correlates of minimal myocardial changes can be analyzed using a commercially available rapid assay. Biomarkers are considered more sensitive markers of subclinical cardiotoxicity than conventional electrocardiographic and echocardiographic methods. The aim of this study was to determine the values of plasma N-terminal pro brain natriuretic peptide (NT-pro-BNP) and cardiac troponin T (cTnT) in asymptomatic childhood leukemia survivors after anthracycline therapy in comparison with healthy volunteers. The survivors also underwent a detailed echocardiography. Twenty six survivors of leukemia previously treated with anthracyclines with total cumulative dose 95-600 (median 221) mg/m(2) were evaluated. Analyses of cTnT and NT-proBNP from blood samples and echocardiography were performed 5-25 years after completion of therapy for childhood leukemia. Control group for biochemical analyses consisted of 22 age- and gender- matched apparently healthy volunteers. Values of NT-proBNP were significantly elevated in ANT group compared to controls (35.1 +/- 37.8 vs. 9.6 +/- 6.7 pg/ml, P<0.010). CTnT remained below the diagnostic cut-off values in both groups. All echocardiographic parameters of patients remained normal. In conclusion, differences in NT-proBNP values between patients treated with anthracyclines and healthy volunteers might signal an initial stage of anthracycline-induced myocardial damage. The potential of this biomarker to detect subclinical anthracycline-induced myocardial alterations before development of echocardiographic and clinical changes is promising.

Frequency-domain analysis of the signal-averaged electrocardiogram in hematological malignancies survivors

OBJECTIVES

The aim of the presented study was to evaluate the frequency-domain signal-averaged ECGs (SAECG) abnormalities in childhood and adolescence acute leukemia and lymphoma survivors treated either with or without anthracyclines (ANT) containing chemotherapy in comparison with healthy volunteers.

BACKGROUND

The late development of chemotherapy-induced myocardial complications becomes an issue as the number of childhood cancer survivors is increasing. Underlying cardiac impairment may progress to serious cardiac diseases. Therefore, an early identification of myocardial injury is essential. PATIENTS AMD METHODS: Study population was divided into two treatment groups: ANT group (31 patients previously treated with ANT), and non-ANT group (32 patients who underwent chemotherapy without ANT, both more than 5 years ago). SAECG was added to routine cardiology examination in the whole population study and 32 controls. Using the frequency-domain analysis within the QRS complex a ratio (AR) of 20-50 (Hz)/0-20 (Hz) was calculated.

RESULTS

AR 20-50/0-20 in SAECG was significantly higher in ANT and non-ANT groups, relative to controls (262.5 p < 0.00001 vs. 135.9 p < 0.001 vs. 74.7). The difference between both patient groups was also evident p < 0.01.

CONCLUSION

Significant differences in frequency-domain SAECG parameters between patients (with or without anthracyclines) and controls might indicate the increased risk of electrical instability particularly in anthracycline-treated patients (Tab. 2, Fig. 1, Ref. 34).