Comparative studies of the sensitivities of sparse and full geometries of Total-Body PET scanners built from crystals and plastic scintillators

BACKGROUND

Alongside the benefits of Total-Body imaging modalities, such as higher sensitivity, single-bed position, low dose imaging, etc., their final construction cost prevents worldwide utilization. The main aim of this study is to present a simulation-based comparison of the sensitivities of existing and currently developed tomographs to introduce a cost-efficient solution for constructing a Total-Body PET scanner based on plastic scintillators.

METHODS

For the case of this study, eight tomographs based on the uEXPLORER configuration with different scintillator materials (BGO, LYSO), axial field-of-view (97.4 cm and 194.8 cm), and detector configurations (full and sparse) were simulated. In addition, 8 J-PET scanners with different configurations, such as various axial field-of-view (200 cm and 250 cm), different cross sections of plastic scintillator, and multiple numbers of plastic scintillator layers (2, 3, and 4), based on J-PET technology have been simulated by GATE software. Furthermore, Siemens' Biograph Vision has been simulated to compare the results with standard PET scans. Two types of simulations have been performed. The first one with a centrally located source with a diameter of 1 mm and a length of 250 cm, and the second one with the same source inside a water-filled cylindrical phantom with a diameter of 20 cm and a length of 183 cm.

RESULTS

With regards to sensitivity, among all the proposed scanners, the ones constructed with BGO crystals give the best performance ([Formula: see text] 350 cps/kBq at the center). The utilization of sparse geometry or LYSO crystals significantly lowers the achievable sensitivity of such systems. The J-PET design gives a similar sensitivity to the sparse LYSO crystal-based detectors while having full detector coverage over the body. Moreover, it provides uniform sensitivity over the body with additional gain on its sides and provides the possibility for high-quality brain imaging.

CONCLUSION

Taking into account not only the sensitivity but also the price of Total-Body PET tomographs, which till now was one of the main obstacles in their widespread clinical availability, the J-PET tomography system based on plastic scintillators could be a cost-efficient alternative for Total-Body PET scanners.

Efficiency determination of J-PET: first plastic scintillators-based PET scanner

BACKGROUND

The Jagiellonian Positron Emission Tomograph is the 3-layer prototype of the first scanner based on plastic scintillators, consisting of 192 half-metre-long strips with readouts at both ends. Compared to crystal-based detectors, plastic scintillators are several times cheaper and could be considered as a more economical alternative to crystal scintillators in future PETs. JPET is also a first multi-photon PET prototype. For the development of multi-photon detection, with photon characterized by the continuous energy spectrum, it is important to estimate the efficiency of J-PET as a function of energy deposition. The aim of this work is to determine the registration efficiency of the J-PET tomograph as a function of energy deposition by incident photons and the intrinsic efficiency of the J-PET scanner in detecting photons of different incident energies. In this study, 3-hit events are investigated, where 2-hits are caused by 511 keV photons emitted in [Formula: see text] annihilations, while the third hit is caused by one of the scattered photons. The scattered photon is used to accurately measure the scattering angle and thus the energy deposition. Two hits by a primary and a scattered photon are sufficient to calculate the scattering angle of a photon, while the third hit ensures the precise labeling of the 511 keV photons.

RESULTS

By comparing experimental and simulated energy distribution spectra, the registration efficiency of the J-PET scanner was determined in the energy deposition range of 70-270 keV, where it varies between 20 and 100[Formula: see text]. In addition, the intrinsic efficiency of the J-PET was also determined as a function of the energy of the incident photons.

CONCLUSION

A method for determining registration efficiency as a function of energy deposition and intrinsic efficiency as a function of incident photon energy of the J-PET scanner was demonstrated. This study is crucial for evaluating the performance of the scanner based on plastic scintillators and its applications as a standard and multi-photon PET systems. The method may be also used in the calibration of Compton-cameras developed for the ion-beam therapy monitoring and simultaneous multi-radionuclide imaging in nuclear medicine.

CardioneuROablation for reflex syncope: efficacy and effects on autonoMic cArdiac regulatioN. The Roman 1 study

Purpose

To assess the effects of CNA on syncope recurrences in patients with VVS

Methods

The Roman 1 study was a prospective, randomized, investigator-initiated trial comparing CNA versus optimal standard therapy in patients with asystolic VVS. Patients were included if they had documented symptomatic cardioinhibitory or mixted spontaneous VVS (at least 3 seconds of asystole), frequent and/or severe symptoms (at least one syncope or 3 presyncopal events during preceding 12 months or very severe syncope in the past, leading to injury) and positive atropine test (>30% increase in sinus rate). CNA was performed using RF ablation of the ganlionated plexi from the left and right atrium. Follow-up lasted 2 years. Primary endpoint was time to first syncope recurrence. One of secondary endpoints were changes in quality of life (QoL) assessed using dedicated questionnaire The Impact of Syncope on Quality-of-Life Questionnaire University of Calgary.

Results

48 patients (17 males, mean age 38±10, 24 – CNA group, 24 – control group) entered the study. Baseline demographic and clinical characteristics were similar in both groups. The primary end-point – syncope recurrence, occurred in 2 (8%) patients from the CNA group versus 12 (50%) controls (p=0.00037, see Kaplan-Meier curve). QoL significantly improved in the CNA group (30±10 vs 10±7 points, p=0.0001) whereas remained stable in controls (31±10 vs 30±10 points, p=0.5501).

Conclusion(s)

This is the first randomized study documenting efficacy of CNA in patients with asystolic VVS. Larger studies are needed to confirm these findings.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Centre of Postgraduate Medical Education

Size-dependent theoretical and experimental photothermal conversion efficiency of spherical gold nanoparticles

INTRODUCTION

Due to their biocompatible and plasmonic properties, gold nanoparticles (Au NPs) are good candidates to be photosensitizers in photothermal cancer therapy (PTT).

MATERIALS AND METHODS

In this paper, the dependence of the NIR-light-to-heat energy on Au NPs size was investigated. Moreover, to determine the photosensitizing properties of gold nanoparticles, PTT was conducted on two colon cell lines: SW480 and SW620 by irradiating them with two lasers having different wavelengths.

RESULTS

Transmission electron microscopy showed that the respective sizes of Au NPs were 10 nm, 12 nm and 16 nm. Moreover, local as well as global structural measurements showed that all synthesized Au NPs were crystalline and UV-Vis spectroscopy revealed that with increasing nanoparticles size the position of the surface Plasmon resonance (SPR) peaks is shifted to higher wavelengths. Decrease of cells viability was observed, when they were cultured with Au NPs and irradiated by 650 nm and 808 nm lasers. Moreover, FTIR and Raman spectra of cells, showed structural changes in DNA, phospholipids, proteins and cholesterol caused by the addition of nanoparticles and laser irradiation. The chemical changes were more pronounced in the cells cultured with Au NPs and irradiated by 650 nm lasers and these changes were dependent on the nanoparticle size. Moreover, the viability of cells investigated by the MTS assay showed, that the percentage of dead cells (∼40%) is the highest for cells cultured with 8 nm Au NPs and irradiated by the 650 nm laser. The photothermal conversion efficiency calculated from the experimental results showed a decrease of this parameter from 70% to 55% and from 61% to 48% with increasing particle size, for 650 nm and 808 nm lasers, respectively.

CONCLUSIONS

The obtained results showed that the photothermal conversion efficiency of Au NPs is size-tunable, and can be correlated with the absorption/extinction ratios calculated by the Mie theory.

Optimal catheter-tissue contact value for ablation of ventricular arrythmias originating from the left ventricular papillary muscles

Funding Acknowledgements

Type of funding sources: None.

Background

Good catheter-tissue contact is mandatory to create effective ablation lesions. The minimal contact force (CF) value for successful ablation of arrhythmias originating from the left ventricle (LV) was reported at the 8-10 g level, however, optimal CF values for ablation of arrhythmias arising from papillary muscles (PM) are not known.

Purpose

To determine optimal CF value for ablation of arrhythmias from LV PM.

Methods

Twenty-four consecutive patients (mean age 57,9 ± 11,9 years, 16 males) who from May 2017 to June 2020 underwent ablation of premature ventricular complexes (PVC) originating from LV PM were included. The primary endpoints were an acute procedural success (total elimination of PVC) and long-term success (median 27 months). Ablation was performed with the use of the CARTO electro-anatomical system and intracardiac echocardiography (ICE).

Results

Acute success – complete abolition of PVC, was obtained in 23 (96%) patients. The fluoroscopy time was 3,9 ± 3,5 min and the procedure duration was 114,8 ± 38 min. The mean number of applications was 8,74 ± 6,78 and the mean application time - 518,5 ± 437,25 sec. The mean CF during successful ablations was 3,1 ± 1,5 g, with 3 ± 1,1 g and 3,18 ± 1,8 g for anterolateral and posteromedial PM, respectively (p= 0,809975). The mean CF during one unsuccessful ablation was 3 g. At control Holter ECG, the mean PVC burden in all patients was reduced from 28,36 ± 14,48 % to 2,42 ± 2 %: in the anterolateral PM group from 18 ± 8 % to 2,6 ± 2 % (p= 0,005415) and in the posteromedial PM group - from 34,8 ± 13,7 % to 1,7 ± 1,3 % (p= 0,012694). During long-term follow-up (median 27, IQR 17-34) there was one recurrence among 23 patients who had acutely successful procedures.

Conclusion

The values of CF for successful ablation of PVC originating from LV PM are lower than those for ablation in other parts of LV. The values slightly exceeding 3 g seem to be sufficient to achieve ablation success.

Bipolar catheter ablation for highly refractory cardiac arrhythmia - does the success rate depend on arrhythmia origin?

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Despite technological progress, some arrhythmias are still refractory to standard unipolar ablation. They include arrhythmias arising from left ventricular (LV) summit, cardiac crux or epicardium. Bipolar ablation may be useful in some cases, however, data on efficacy of this approach in various arrhythmia localisatons are scarse.

Purpose

Aim of the study was to assess efficacy of bipolar catheter ablation in patients with cardiac arrhythmias refractory to standard ablation approach.

Methods

Observational, single-center study was conducted over 30-month period. Twenty-six consecutive patients (male=18, aged = 54.26 ± 16.4) who were referred for bipolar ablation were included. All patients had a history of previously failed unipolar ablation procedures. Bipolar ablations were performed using dedicated RF generator and electroanatomic mapping system.

Results

Twenty-seven procedures in 26 patients with a mean of 2.52 ± 0.83 previously failed unipolar ablations were included in the final analysis. There were 4 ablations of accessory pathways (3 postero-septal and 1 left free wall) with acute success rate of 100%, 11 procedures of ventricular arrhythmias originating from crux of the heart with acute success rate of 73% and 12 from left ventricular summit (LV summit) with acute success rate of 50%. Mid-term success rate (median follow-up of 182 days) was 100%, 63% and 50% respectively. There was one major complication (not related to RF bipolar ablation): cardiac tamponade due to aortic cusp rupture requiring urgent cardiac surgery procedure.

Conclusions

Bipolar ablation is a promising method of catheter ablation for refractory arrhythmias. The highest success rate was observed in ablation for difficult pathways, followed by ventricular arrhythmias originating from cardiac crux and LV summit.

Simulating NEMA characteristics of the modular total-body J-PET scanner-an economic total-body PET from plastic scintillators

The purpose of the presented research is estimation of the performance characteristics of the economic total-body Jagiellonian-PET system (TB-J-PET) constructed from plastic scintillators. The characteristics are estimated according to the NEMA NU-2-2018 standards utilizing the GATE package. The simulated detector consists of 24 modules, each built out of 32 plastic scintillator strips (each with cross section of 6 mm times 30 mm and length of 140 or 200 cm) arranged in two layers in regular 24-sided polygon circumscribing a circle with the diameter of 78.6 cm. For the TB-J-PET with an axial field-of-view (AFOV) of 200 cm, a spatial resolutions (SRs) of 3.7 mm (transversal) and 4.9 mm (axial) are achieved. The noise equivalent count rate (NECR) peak of 630 kcps is expected at 30 kBq cc^-1. Activity concentration and the sensitivity at the center amounts to 38 cps kBq^-1. The scatter fraction (SF) is estimated to 36.2 %. The values of SF and SR are comparable to those obtained for the state-of-the-art clinical PET scanners and the first total-body tomographs: uExplorer and PennPET. With respect to the standard PET systems with AFOV in the range from 16 to 26 cm, the TB-J-PET is characterized by an increase in NECR approximately by factor of 4 and by the increase of the whole-body sensitivity by factor of 12.6 to 38. The time-of-flight resolution for the TB-J-PET is expected to be at the level of CRT = 240 ps full width at half maximum. For the TB-J-PET with an AFOV of 140 cm, an image quality of the reconstructed images of a NEMA IEC phantom was presented with a contrast recovery coefficient and a background variability parameters. The increase of the whole-body sensitivity and NECR estimated for the TB-J-PET with respect to current commercial PET systems makes the TB-J-PET a promising cost-effective solution for the broad clinical applications of total-body PET scanners. TB-J-PET may constitute an economic alternative for the crystal TB-PET scanners, since plastic scintillators are much cheaper than BGO or LYSO crystals and axial arrangement of the strips significantly reduces the costs of readout electronics and SiPMs.

Ultrasound-guided extra-cardiac vagal stimulation during cardioneuroablationa-a pilot feasibility study

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

N/A

Background. Cardioneuroablation (CNA) is a promising method for treatment of vagally-induced vasovagal syncope or functional atrio-ventricular block. Extra-cardiac vagal stimulation (ECVS) from the internal jugular vein is used during CNA to document asystolic response prior to CNA and lack of effects of vagal stimulation on heart rate after CNA.  The recommended technique is placing the pacing catheter under fluoroscopy in the internal right and left jugular vein up to the level of the upper wisdom tooth. However, this technique has several limitations such as increased radiation exposure, unselective cranial nerves stimulation and lack of visualization of vagal nerve. Ultrasound-guided (USG) approach may be an interesting option because it allows visualization of the vagal nerve and enables selective  stimulation under visual control.

Purpose. To assess the utility of USG-guided ECVS during CNA procedures.

Methods. The study group consisted of 6 patients (4 males, mean age 35 ± 12-year-old) underwent CNA.  Firstly, electrode for ECVS was introduced under fluoroscopy into the right and left jugular veins up to the level of the upper wisdom tooth and ECVS was performed. Next, the USG-guided examinations were performed in supine position with head extension. The probe was placed in the transverse plane above the medial edge of the sternocleidomastoid muscle. The course of vagal nerve was identified and place for imaging in the close neighborhood of the jugular vein was chosen. ECVS was performed when the electrode was in good contact with the vein wall and was in the vicinity of the vagal nerve. In both approaches vagal response (asystole and atrio-ventricular block) during ECVS was assessed before and after CNA.

Results. In all patients ECVS was performed from both right and left jugular vein. Localization of vagal nerve using USG was possible in all patients and took less than one minute (see Figure). The effects of ECVS were identical using standard fluoroscopic and USG-guided approach.

Conclusions. USG-guided ECVS during CNA is easy, results are comparable with standard fluoroscopic approach and is probably associated with less fluoroscopy. Since this non-invasive method is the only one which enables vagal nerve visualization, it should become a preferred approach when using ECVS during CNA procedures. Abstract Figure. A electrode position for USG-guided ECVS

Left atrial function after successful catheter ablation for paroxysmal atrial fibrillation: cryoablation versus radiofrequency techniques

Funding Acknowledgements

Type of funding sources: None.

Purpose

It has been suggested that cryoballoon (CB) ablation for paroxysmal atrial fibrillation (PAF) may lead to more extensive left atrial (LA) injury than radiofrequency (RF) ablation, however, results are conflicting. We sought to address this issue using modern echocardiographic techniques.

Methods

We performed transthoracic echocardiography in 90 patients (66% males, mean age 57 ± 10 years) successfully treated  with RF (51%) or CB (49%) ablation for PAF before and 6 months after the procedure. Peak longitudinal LA strain (LAS) and strain rate (LASR) during the reservoir (r), conduit (cd) and contraction (ct) phases were measured during sinus rhythm by speckle tracking. The LA diameter and volume (LAV) index - using biplane area-length method divided by the body surface area were also calculated.

Results

The LA diameter decreased (38.1 ± 4.0 vs 37.2 ± 3.8 mm, p = 0.004), the LAV index did not change (33.5 ± 11.9 vs 34.4 ± 8.9 mL/m², p = 0.272) at 6 months in the whole study group. The LASRr and LASRcd increased, whereas there were no changes in remaining LA function parameters in either ablation strategy (table). The CB subgroup did not differ in LA function parameters comparing to RF subgroup at six months after procedure (table).

Conclusion

CB and RF ablation did not differentially affect the LA function. Successful ablation for PAF resulted in improvement of  rate of deformation during reservoir and conduit LA cycle and stable contractile LA function.

LA function parameters RF N = 46 (51%) CB N = 44 (49%) 6 months RF vs CB Parameter Baseline 6 months p Baseline 6 months p p* Global LASr [%] 27.7 ± 6.35 27.9 ± 6.0 0.833 27.9 ± 7.2 27.0 ± 6.4 0.370 0.539 Global LAScd [%] -14.6 ± 4.1 -14.8 ± 4.6 0.761 -15.3 ± 5.3 -14.1 ± 3.2 0.080 0.399 Global LASct [%] -13.0 ± 4.84 -13.0 ± 3.20 1.00 -12.6 ± 3.81 -12.9 ± 4.18 0.629 0.897 Global LASRr [sˉ¹] 1.18 ± 0.22 1.27 ± 0.26 0.046 1.07 ± 0.27 1.18 ± 0.30 0.041 0.141 Global LASRcd [sˉ¹] -1.11 ± 0.33 -1.25 ± 0.35 0.013 -1.07 ± 0.31 -1.16 ± 0.30 0.044 0.214 Global LASRct [sˉ¹] -1.46 ± 0.40 -1.50 ± 0.31 0.500 -1.42 ± 0.51 -1.39 ± 0.42 0.742 0.187 *p value corrected for baseline values

P1096Cardioneuroablation changes the type of vaso-vagal response in patients with asystolic reflex syncope

Funding Acknowledgements

Centre of Postgraduate Medical Education No. 501-1-10-14-19

Background. Cardioneuroablation (CNA) - ablation of ganglionated plexi (GP) to eliminate or reduce parasympathetic overactivity, has been recently proposed as a new therapeutic method in patients with vaso-vagal syncope (VVS) due to cardioinhibitory or mixed mechanism.

Purpose. To assess the impact of CNA on the type of VV response during tilt testing (TT).

Methods. The study group consisted of the first 20 patients (7 males, mean age 38 ± 9 – year – old) enrolled in the ongoing prospective Roman study (NCT 03903744). All patients had a history of ECG documented syncope due to asystole and confirmed asystolic form of VVS at baseline TT. CNA was performed using electroanatomical system Carto 3 and radiofrequency applications delivered in the right and left atrium at the right anterior GP and right inferior GP sites. The second TT was performed three months later. Resting heart rate (HR) and heart rate variability parameter (SDDN) were also assessed.

Results. At baseline TT, nineteen patients had cardioinhibitory syncope (asystole ranging from 3 to 60 s)  (sinus node arrest – 17 patients, A-V block – 2 patients) and 1 had mixed form of VVS (asystole lasting 3 s preceded by hypotension). During three-month follow-up no syncopal episodes were noted. At the 3-month TT, 6 (30 %) patients had no syncope whereas the remaining 13 (65 %)  had syncope – twelve (60 %) due to vasodepressor mechanism and only one (5 %) due to asystole - as before CNA. One patient did not have TT because of pregnancy. Mean resting HR after CNA was significantly faster and SDNN significantly lower than before the procedure (82 ± 9 vs 69 ± 11 beats/min, p = 0.0004 and 74 ± 22 vs 143 ± 40 ms, p = 0.00003, respectively) and these changes were was similar in those who fainted during second TT and those who did not (82 ± 11 vs 81 ± 4 beats/min, p = NS and (75 ± 2 vs 77 ± 18 ms, p = NS, respectively).

Conclusions. CNA profoundly affects the type of VV reaction causing normalization of the response to tilting or changing cardiodepression to vasodepression. These effects are also depicted by changes in HR and heart rate variability. Elimination of TT-induced reflex asystole may prevent clinical recurrences of syncope during short-term follow-up. These findings encourage to conduct further studies involving CNA since this method appears to be effective and obviates the need for pacemaker implantation in young people with reflex asystolic syncope.

[Study of practices: What do general practitioners first propose when faced with asymptomatic lower extremity peripheral artery disease?]

INTRODUCTION

Peripheral artery disease of lower limbs (PAD) can be discovered at an asymptomatic stage by the realization of systolic pressure indices. The 2006 recommendations of the French National Authority for Health on AOMI encourage the systematic prescription of antiplatelet agents; the 2012 recommendations on the proper use of antiplatelet agents no longer encourage it in the case of asymptomatic PAD. These two recommendations still coexist. Our objective was to determine the management of an asymptomatic PAD by general practitioners.

METHODS

Descriptive and analytical epidemiological study, with analysis of practices, prospectively addressed by postal questionnaire to a randomized sample of 220 GPs practicing in the European Metropolis of Lille between December 15, 2016 and February 15, 2017. The question was: "if an asymptomatic PAD is discovered in a 50-year-old patient who is otherwise in good general condition, what do you generally do?"

RESULTS

Our sample was 92 general practitioners (42% participation). Of these, only 6 were practicing HPIs. Before an asymptomatic PAD, management included an opinion from an angiologist (84%) and/or a cardiologist (75%) before the drug was prescribed (antiplatelet agent for 57%, statin for 33% and ACE inhibitor for 14%).

CONCLUSION

The extension assessment was carried out in more than 8 out of 10 cases. The use of antiplatelet antiaggregants was significant, which can be explained by the coexistence of divergent recommendations. The rapid clarification of recommendations is essential with the evolution of scientific data.

From spherical to bone-shaped gold nanoparticles-Time factor in the formation of Au NPs, their optical and photothermal properties

Using the same synthesis method, which was stopped at different time intervals, gold nanoparticles (Au NPs) with different shapes, from spherical to bone-shaped, were obtained. The physical properties of the synthesized Au NPs were investigated using transmission electron microscopy (TEM) combined with selected area electron diffraction patterns (SAED) and ultraviolet-visible spectroscopy (UV-vis). The TEM images showed, that stopping the synthesis after one minute lead to the formation of small spherical Au NPs, which evolved to the cubic shape, rods and bone-shaped Au NPs after 15 min, 30 min, 2 h, respectively. SAED patterns showed, that all the obtained Au NPs were crystalline. UV-vis spectra revealed, that the light absorbance depends on the shape of the Au NPs. Moreover, the effects of the time factor in the formation of Au NPs on the effective conversion of electromagnetic energy into thermal energy, was studied. Furthermore, simulated photothermal therapy (PTT) in combination with the obtained NPs, was done for two cancer cell lines SW480 and SW620. The mortality of cells after using the differently shaped Au NPs as photosensitizers is between 18 % and 52 % and increases with the decrease of the synthesis time.

P318 Left atrial dysfunction assessed by echocardiography in relation to left atrial fibrosis in patients undergoing ablation for atrial fibrillation

PURPOSE

Left atrial (LA) fibrosis is the hallmark of LA remodeling in atrial fibrillation (AF), alters LA function and may predict poor catheter ablation (CA) outcome. LA fibrosis may be assessed invasively using electroanatomical mapping (EAM) during electrophysiological study.

The aim was to assess LA function parameters in relation to degree of LA fibrosis derived from EAM in patients with AF.

METHODS

Patients (pts) n = 39 (79% males, mean age 56+/-10) with non-valvular AF were studied with TTE and TEE before first CA during sinus rhythm. LA strain (LAS) and strain rate (LASR) were analyzed in reservoir (r), conduit (cd) and contractile (ct) phases. The velocities of mitral A, E" and A" were measured with Doppler. E/E" and LA stiffness index - the ratio of E/E" to LASr were assessed. LA appendage flow velocity (LAAv) was measured in TEE. LA volume using biplane area-length method was calculated.

The EAM of LA was build using Carto System before CA. Low amplitude potentials area (LAPA) was quantitatively analyzed and expressed as a percentage of LA surface using the cut-off <0.5 mV to detect sites of fibrosis. LA parameters were compared between mild (LAPA <10%) moderate (LAPA 10-40%) and extensive degree of LA fibrosis (LAPA >40%) (table).

RESULTS

The mean LA volume was 35 ± 11 mL/m². The LAPA ranged from 2 to 78 % of LA surface. Reduced LA function was observed in the LAPA >40% group. Extensive LAPA altered mainly LA compliance parameters. Traditional LA systolic function parameters did not differ in relation to degree of LAPA.

CONCLUSION

LA compliance is mostly affected by LA fibrosis, thus LA diastolic parameters may be useful in the noninvasive assessment of LA fibrosis. Whether these parameters should be a part of the proper selection of candidates for CA requires further studies.

LA function parameters LA parameters Group 1 LAPA <10% n = 13 Group 2 LAPA >10% <40% n = 13 Group 3 LAPA >40% n = 13 P-value Group 1 + 2 vs 3 Mitral A 0.55 ± 0.10 0.55 ± 0.24 0.73 ± 0.32 0.077 A" 9.19 ± 1.74 7.85 ± 1.43 7.92 ± 2.40 0.376 LASr 31.48 ± 4.52 26.48 ± 8.79 19.63 ± 6.76 <0.001 LAScd 17.30 ± 3.05 15.44 ± 6.93 10.91 ± 4.04 0.003 LASct 14.18 ± 5.36 11.05 ± 3.67 8.72 ± 4.78 0.024 LASRr 1.22 ± 0.19 1.24 ± 0.21 0.92 ± 0.20 <0.001 LASRct -1.71 ± 0.46 -1.37 ± 0.34 -1.04 ± 0.33 <0.001 LA stiffness 0.20 ± 0.07 0.34 ± 0.17 0.63 ± 0.29 <0.001 LAAv 0.83 ± 0.18 0.55 ± 0.17 0.60 ± 0.16 0.178

The role of chemokine CCL5/RANTES and metalloproteinase-9 as inflammatory modulators in symptomatic internal carotid artery stenosis

Up to 80% of all ischemic strokes (IS) attributed to internal carotid athero-occlusive artery stenosis (ICAS) are related to a thromboembolic mechanism. One athero-occlusive ischemic event increases the risk for ischemia in another vascular territory, resulting from inflammation within the atherosclerotic plaque induced by cytokines. Thus, ultrasonographic characteristics of vulnerable plaques in ICAS, including plaque echolucency and ulceration might correspond to cytokine activity. The present study aimed to investigate the associations between serum cytokines and atherosclerotic plaque characteristics and the 3-year risk of a major adverse coronary and carotid ischemic event (MACCE) in symptomatic patients treated for ICAS. Plaque characteristics on ultrasonography, serum levels of C-C motif chemokine ligand 5 (CCL5)/regulated on activation, normal T-cell expressed and secreted (RANTES), metalloproteinase-9 (MMP-9), interleukin-6 (IL-6), transforming growth factor beta (TGF-β), C-X-C motif chemokine ligand 16 (CXCL16), FAS ligand (FASL) and high sensivity C-reactive protein (hs-CRP) were analyzed in 103 symptomatic patients with ICAS prior to carotid revascularization. The incidence of MACCE: cardiovascular death (CVD), myocardial infarction (MI) and recurrent ischemic stroke (IS) were recorded prospectively for up to 5 years (median 37; IQR 21 - 40 months). Echolucent plaques, in comparison to echogenic plaques, displayed lower median levels of RANTES (P = 0.042) but higher median levels of IL-6 (P = 0.039). There was no relationship between plaque characteristics and median levels of MMP-9, TGF β, CXCL16, FASL, or hs-CRP (P = NS). During follow-up, MACCE occurred in 15 (14.6%) patients. Univariate Cox proportional hazard analysis indicated median RANTES levels < 45.5ng/mL (hazard ratio (HR) = 3.95; 95%CI = 1.10 - 14.2; P = 0.035), MMP-9 > 0.6 μg/mL (HR 4.5; 95%CI = 1.4 - 13.9; P = 0.009), renal impairment (HR 3.48; 95%CI = 1.29 - 9.34; P = 0.013) as potential MACCE risk factors. On multivariate Cox proportional hazard analysis, MMP-9 > 0.6 μg/mL and RANTES < 45.5 ng/ml were associated with a 4.72-fold (95%CI = 1.3 - 17.0; P = 0.017) and a 3.8-fold risk increase (95%CI = 1.07 - 13.89; P = 0.038) of MACCE. Kaplan-Meier analysis showed significant differences in MACCE-free survival rates depending on RANTES and MMP-9 median levels. We conclude that serum RANTES, IL-6, and MMP-9 were associated with plaque vulnerability and predicted adverse MACCE in patients treated for ICAS.

Platinum-gold nanoraspberries as effective photosensitizer in anticancer photothermal therapy

BACKGROUND

New nanophotosensitizers for photothermal cancer therapy (PTT) are still sought. In this paper we propose fancy shaped, non agglomerated core/shell PtAu NRs nanoraspberries (PtAu NRs) as potential nanophotosensitizers in PTT.

RESULTS

Light microscopy images of two colon cancer cell lines (SW480, SW620) showed, that the laser irradiation combined with PtAu NRs caused visible changes in the cell morphology. Fourier Transform InfraRed (FTIR) and Raman spectroscopies showed chemical changes in the DNA, phospholipids, lipids and protein structures caused by laser irradiation in the presence of PtAu NRs. The MTS assay showed ~ 25% mortality of cancer cells due to the addition of PtAu NRs to the cell culture, while for laser irradiation combined with nanoparticles, the mortality of cancer cells increased to 65% for the 650 nm laser and to 60% for the 808 nm laser. The calculated photothermal conversion efficiency reached 62% and 51% for the 650 nm and 808 nm lasers, respectively.

CONCLUSIONS

PtAu NRs could be applied as effective light-absorbers in the PTT anticancer therapy.

Serum rantes, transforming growth factor-β1 and interleukin-6 levels correlate with cardiac muscle fibrosis in patients with aortic valve stenosis

Regulated on Activation Normal T Expressed and Secreted (RANTES) chemokine is involved in the initiation of inflammation and immune-cell recruitment. Interleukin -6 (IL-6) is used as a general index of severity of the chronic inflammatory process. Finally, transforming growth factor-β (TGF-β) is an immune biomarker potentially involved in the regulation of valve fibrosis and calcification. The aim of this study was to analyze selected biomarkers associated with the different stages of immune-pathogenesis in aortic stenosis. Forty consecutive patients with moderate to severe aortic stenosis (AS) and without previous myocardial infarction history were included in the study and divided into two groups. Two imaging techniques, echocardiography and magnetic resonance, were used to estimate the degree of AS and left ventricular muscle function. Inflammatory biomarker serum levels including CCL5/RANTES, IL-6, and TGF-β1 were determined based on ELISA measurements. Mean levels of RANTES, IL-6, and TGF-β1 did not significantly differ between both groups. A negative correlation was found between RANTES serum level and left ventricle (LV) mass as assessed by MRI (r = -0.3358, P = 0.0341). A positive correlation (r = 0.3283, P = 0.0387) was found between IL-6 serum levels and LV mass as measured by MRI. In addition, a positive correlation (r = 0.6803, P = 0.01) was seen between IL-6 serum levels and LV muscle mass with positive late gadolinium enhancement (LGE). There was a positive correlation between TGF-β1 serum level and ejection fraction as measured by echocardiography (r = 0.3217, P = 0.043). The relationship between selected inflammatory biomarkers, LV ejection fraction, LV mass, and LV muscle mass with LGE appeared to be independent of valvular pathobiologic process severity, as we did not observe differences in IL-6, RANTES, or TGF-β1 between groups differing in severity. On the contrary, these markers appear to be linked to myocardial function and remodeling, which may provide valuable insights into the pathobiology of AS and provide a basis for future detection strategies of AS.

Widely used hardly known. An insight into electric and dynamic properties of formamidinium iodide

The simple organic crystal formamidinium iodide (FAI) appeared to be a novel semiconducting material in a wide temperature range. The electric properties of FAI and the role of formamidinium cation (FA⁺) in the molecular mechanism of the solid-to-solid phase transitions (at 345 K (III → II) and 388 K (II → I)) were analysed. The creation of the ferroelastic domain structure in phases III and II was proved on the basis of observation under a polarizing microscope. Moreover, the molecular arrangement of dipolar organic FA⁺ was studied by ¹H NMR (spin-lattice relaxation time) and vibrational spectroscopy supported by density functional theory. The theoretical results show a good agreement with the experimental data. The infrared spectrum in a harmonic approximation was calculated and a comparative vibrational analysis was performed. All used techniques showed that the prototypic phase I exhibits the feature of plastic phase.

The simple organic crystal formamidinium iodide (FAI) appeared to be a novel semiconducting material in a wide temperature range.

Spectroscopy of the Surface Polaritons in the CdXZn(1-X)P2 Solid Solutions

Here we report on the analysis of the effect of the doping of CdP₂ single crystals by ZnP₂ nanoclusters on the dispersion of the surface polaritons (SP). The ATR spectroscopic technique has been applied to excite the SP in the Cd_XZn_(1-X)P₂ system. Analysis of the obtained spectra has shown that the doping of CdP₂ single crystals by ZnP₂ nanoclusters result in the position and the width of the dispersion branches of the SP. This effect is more pronounced in the low frequency dispersion branches. These SP branches are originated from phonons which correspond to the motion of the cation sublattice.

Fourier transform infrared and Raman spectroscopy in the study of phase transitions in dipyrazolium iodide triiodide: Experimental and theoretical analysis

The paper presents the Infrared and Raman spectra of the powdered [C₃N₂H₅⁺]₂[I^-∙I₃^-] crystal at the temperature intervals of 11-270K, covering two low-temperature phase transitions: discontinuous at 182/188K (cooling/heating) and continuous at 254K. The research shows that the vibrational states of the pyrazolium cations change significantly during discontinuous phase transition (III→II), while the continuous nature of successive structural transformation is more subtle and displays an insignificant change in the temperature coefficient of numerous vibrations during the II→I PT at 254K. The spectacular changes at Raman spectra above 188K confirm a huge rebuilding of inorganic network from [I^-∙I₃^-] to [I₄^2-]. Additionally, a complete geometry optimization was carried out in the solid state in order to obtain minimum structures and bonding properties. The theoretical results correspond well with the experimental data. Moreover, the infrared spectrum in harmonic approximation was calculated, and a comparative vibrational analysis was performed. CRYSTAL09 vibrational results appear to be in a good agreement with the experimental ones.

Structures and phase transitions in neat 4,4′-di-tert-butyl-2,2′-bipyridyl and in its molecular complexes with either bromanilic or iodanilic acid

Using the DSC method, structural phase transitions (PTs) have been found at 165 and 219 K for 4,4′-di-tert-butyl-2,2′-bipyridyl (dtBBP), whereas for its complex with iodanilic acid (dtBBP·IA) PT is found at 331 K.

The Role of ZnP2 Nanoclusters in the Vibrational Properties of Cd x Zn(1 - x)P2 Solid Solutions

This study reports an analysis of the IR reflectance and Raman spectra of Cd x Zn(1 - x)P2 solid solutions. We have analyzed the effect of the doping of the CdP2 single crystal by the ZnP2 nanoclusters on the vibrational properties of studied samples: ε 0, ε inf, phonon frequencies, and strengths. These dependencies might be used as an alternative non-destructive way for the control of the Cd x Zn(1 - x)P2 composition. The obtained results show that variation of the concentration of ZnP2 nanoclusters opens a space to design the tailored material properties for the industrial applications.

Structure–property relationships in hybrid (C3H5N2)3[Sb2I9] and (C3H5N2)3[Bi2I9] isomorphs

Two hybrid crystals imidazolium iodoantimonate(iii) and iodobismuthate(iii) have been synthesized and characterized in a wide temperature range (100–350 K) by means of X-ray diffraction, dielectric spectroscopy, proton magnetic resonance, FT-IR spectroscopy and optical observations.

The role of nucleation in vitrification of supercooled liquids

Low-frequency Raman and differential scanning calorimetry (DSC) investigations were carried out during a structural transformation of supercooled liquid salol (phenyl salicylate) in a wide temperature range. DSC experiments indicate that in the supercooled liquid salol at temperature ~40 K above the glass transition temperature metastable nuclei start to form. During subsequent cooling the nuclei become an important element of the glass structure, and thereby are considered as a measure of the intermediate range order in this glass. It was shown that the crystalline structure of the metastable nuclei differ from that of the stable nuclei. Low-frequency Raman spectra of the glassy salol show a broad band in the spectral range from 14.5 to 17.2 cm(-1); the so called 'Boson peak', which can be interpreted in terms of its relationship to the formation of structured clusters, with typical sizes in the nanometer range (critical radii).

Infrared spectroscopy study of structural changes in glass-forming salol

We report the investigation of glass-forming salol upon different courses of the temperature changes from liquid to glass state and back using FT-IR spectroscopy measurements in the wide spectral and temperature ranges. The formation of the ordered clusters in supercooled liquid salol has been observed at 250 K. When the temperature is decreased further to 11 K these ordered clusters become an element of the glass structure. With increasing temperature to 270 K through the glass transition noticeable evolutions of the IR spectrum occurs up till the ordered clusters are developed into crystal. So produced crystal melts in the temperature range 300-310 K, that corresponds to the melting temperature of the metastable phase (Tmelt=302 K) . Thus, the crystalline structure of the ordered clusters corresponds to the structure of metastable phase and is monoclinic.