Rationale and study design of the prospective, longitudinal, observational cohort study “rISk strAtification in end-stage renal disease” (ISAR) study

Background: The ISAR study is a prospective, longitudinal, observational cohort study to improve the cardiovascular risk stratification in endstage renal disease (ESRD). The major goal is to characterize the cardiovascular phenotype of the study subjects, namely alterations in micro-and macrocirculation and to determine autonomic function. Methods/design: We intend to recruit 500 prevalent dialysis patients in 17 centers in Munich and the surrounding area. Baseline examinations include: (1) biochemistry, (2) 24-h Holter Electrocardiography (ECG) recordings, (3) 24-h ambulatory blood pressure measurement (ABPM), (4) 24 h pulse wave analysis (PWA) and pulse wave velocity (PWV), (5) retinal vessel analysis (RVA) and (6) neurocognitive testing. After 24 months biochemistry and determination of single PWA, single PWV and neurocognitive testing are repeated. Patients will be followed up to 6 years for (1) hospitalizations, (2) cardiovascular and (3) non-cardiovascular events and (4) cardiovascular and (5) all-cause mortality. Discussion/conclusion: We aim to create a complex dataset to answer questions about the insufficiently understood pathophysiology leading to excessively high cardiovascular and non-cardiovascular mortality in dialysis patients. Finally we hope to improve cardiovascular risk stratification in comparison to the use of classical and non-classical (dialysis-associated) risk factors and other models of risk stratification in ESRD patients by building a multivariable Cox-Regression model using a combination of the parameters measured in the study

Greece: Competition Law and the Curious Liberalisation of Professional Services

The progression of EU law: Accommodating change and upholding value

Ambulatory aortic blood pressure, wave reflections and pulse wave velocity are elevated during the third in comparison to the second interdialytic day of the long interval in chronic haemodialysis patients

Background. Increased arterial stiffness and aortic blood pressure (BP) are independent predictors of cardiovascular outcomes in end-stage renal disease. The 3-day interdialytic interval is associated with elevated risk of cardiovascular morbidity and mortality in haemodialysis. This study investigated differences in ambulatory aortic BP and arterial stiffness between the second and third day of the long interdialytic interval. Methods. Ambulatory BP monitoring with Mobil-O-Graph monitor (IEM, Stolberg, Germany) was performed in 55 haemodialysis patients during a 3-day interval. Mobil-OGraph records oscillometric brachial BP and pulse waves and calculates aortic BP and augmentation index (AIx) as measure of wave reflections, and pulse wave velocity (PWV) as measure of arterial stiffness. Results. Ambulatory aortic systolic blood pressure (SBP) and diastolic blood pressure (DBP) were higher during the third versus second interdialytic day (123.6 ± 17.0 versus 118.5 ± 17.1 mmHg, P < 0.001; 81.5 ± 11.8 versus 78 ± 11.9 mmHg, P < 0.001, respectively). Similar differences were noted for brachial BP. Ambulatory AIx and PWV were also significantly increased during the third versus second day (30.5 ± 9.9 versus 28.8 ± 9.9%, P < 0.05; 9.6 ± 2.3 versus 9.4 ± 2.3 m/s, P < 0.001, respectively). Differences between Days 2 and 3 remained significant when day-Time and night-Time periods were compared separately. Aortic SBP and DBP, AIx and PWV showed gradual increases from the end of dialysis session onwards. Interdialytic weight gain was a strong determinant of the increase in the above parameters. Conclusions. This study showed significantly higher ambulatory aortic BP, AIx and PWV levels during the third compared with the second interdialytic day. These findings support a novel pathway for increased cardiovascular risk during the third interdialytic day in haemodialysis. © The Author 2015. Published by Oxford University Press

Evaluation of a novel brachial cuff-based oscillometric method for estimating central systolic pressure in hemodialysis patients

Background/Aims: Elevated wave reflections and arterial stiffness, as well as ambulatory blood pressure (BP) are independent predictors of cardiovascular risk in end-stage-renaldisease. This study is the first to evaluate in hemodialysis patients the validity of a new ambulatory oscillometric device (Mobil-O-Graph, IEM, Germany), which estimates aortic BP, augmentation index (AIx) and pulse wave velocity (PWV). Methods: Aortic SBP (aSBP), heart rate-adjusted AIx (AIx(75)) and PWV measured with Mobil-O-Graph were compared with the values from the most widely used tonometric device (Sphygmocor, ArtCor, Australia) in 73 hemodialysis patients. Measurements were made in a randomized order after 10 min of rest in the supine position at least 30 min before a dialysis session. Brachial BP (mercury sphygmomanometer) was used for the calibration of Sphygmocor's waveform. Results: Sphygmocor-derived aSBP and AIx(75) did not differ from the relevant Mobil-O-Graph measurements (aSBP: 136.3 ± 19.6 vs.133.5 ± 19.3 mm Hg, p = 0.068; AIx(75): 28.4 ± 9.3 vs. 30.0 ± 11.8%, p = 0.229). The small difference in aSBP is perhaps explained by a relevant difference in brachial SBP used for calibration (146.9 ± 20.4 vs. 145.2 ± 19.9 mm Hg, p = 0.341). Sphygmocor PWV was higher than Mobil-O-Graph PWV (10.3 ± 3.4 vs. 9.5 ± 2.1 m/s, p < 0.01). All 3 parameters estimated by Mobil-O-Graph showed highly significant (p < 0.001) correlations with the relevant measurements of Sphygmocor (aSBP, r = 0.770; AIx(75), r = 0.400; PWV, r = 0.739). The Bland-Altman Plots for aSBP and AIx(75) showed acceptable agreement between the two devices and no evidence of systemic bias for PWV. Conclusion: As in other populations, acceptable agreement between Mobil-O-Graph and Sphygmocor was evident for aSBP and AIx(75) in hemodialysis patients; PWV was slightly underestimated by Mobil-O-Graph. © 2014 S. Karger AG, Basel

Ambulatory recording of wave reflections and arterial stiffness during intra- and interdialytic periods in patients treated with dialysis

Background and objectives Wave reflections and arterial stiffness are independent cardiovascular risk factors in ESRD. Previous studies in this population included only static recordings before and after dialysis. This study investigated the variation of these indices during intra- and interdialytic intervals and examined demographic, clinical, and hemodynamic variables related to arterial function in patients undergoing hemodialysis. Design, setting, participants, & measurements Between February 2013 and May 2014, a total of 153 patients receiving maintenance hemodialysis in five dialysis centers of northern Greece underwent ambulatory BP monitoringwith the newly introducedMobil-O-Graph device (IEM, Stolberg,Germany) over amidweek dialysis session and the subsequent interdialytic period. Mobil-O-Graph is an oscillometric device that records brachial BP and pulse waves and estimates, via generalized transfer function, aortic BP, augmentation index (AIx) as a measure of wave reflections, and pulse wave velocity (PWV) as an index of arterial stiffness. ResultsAIxwas lower during dialysis than in the interdialytic period of dialysis-on day (Day 1) (mean±6SD, 24.7% 69.7% versus 26.8%69.4%; P<0.001). In contrast, PWV remained unchanged between these intervals (9.31±62.2 versus 9.29±62.3 m/sec; P=0.60). Both AIx and PWV increased during dialysis-off day (Day 2) versus the out-ofdialysis period of Day 1 (28.8%±69.8% versus 26.8%±69.4% [P<0.001] and 9.39±62.3 versus 9.29±62.3 m/sec [P<0.001]). Older age (odds ratio [OR], 1.09; 95%confidence interval [95% CI], 1.02 to 1.15), female sex (OR, 7.56; 95%CI, 1.64 to 34.81), diabetic status (OR, 8.84; 95%CI, 1.76 to 17.48), and higher mean BP (OR, 1.17; 95%CI, 1.09 to 1.27)were associatedwith higher odds of highAIx; higher heart ratewas associatedwith lower odds (OR, 0.71; 95%CI, 0.63 to 0.80) of high AIx. Older age (OR, 2.04; 95%CI, 1.61 to 2.58) and higher mean BP (OR, 1.15; 95%CI, 1.05 to 1.27) were independent correlates of high PWV. Conclusions This study showed a gradual interdialytic increase in AIx, whereas PWV was only slightly elevated during Day 2. Future studies are needed to elucidate the value of these ambulatory measures for cardiovascular risk prediction in ESRD. © 2015 by the American Society of Nephrology

On the thermal response of LuAG:Ce single crystals

It is well known that the luminescence efficiency of single crystals is affected by external parameters, such as the environmental temperature, especially in harsh environments. Due to this, it is of worth to examine the influence of temperature on the luminescence output of single-crystal scintillators. In this study lutetium aluminum garnet (Lu3Al5O12:Ce-LuAG:Ce) was examined, against previously published data for cadmium tungstate (CdWO4) and calcium fluoride doped with europium (CaF2:Eu) single crystals. Experiments were carried using a medical X-ray source, set to fixed high voltage (90kVp) and tube current/exposure time product (63mAs), in order to record the produced light, under different temperature conditions (20-120 Celsius). An interesting finding is that temperature, in the examined range, appear to have minimal influence on the light output of LuAG:Ce, in the contrary to the previously examined crystals (CdWO4 and CaF2:Eu) where the luminescence output constantly decreased with increasing temperature. The thermal stability of LuAG:Ce, in the examined temperature range, renders it a good choice, besides medical imaging, also for application in harsh environments as well as for long-term operation in high power LEDs. © 2021 The Authors. Published by Elsevier B.V

Ultrasound-guided femoral approach for coronary angiography and interventions in the porcine model

Coronary angiography and percutaneous coronary intervention (PCI) procedural details in swine are similar to those performed to humans, since their heart and coronary anatomy closely resembles. However, only a few detailed descriptions of the procedure are available, containing notable differences. We present a feasible and reproducible protocol for percutaneous coronary interventions in porcine experimental models, utilizing ultrasound-guided femoral approach. Nine female pigs were studied to explore the feasibility of superficial femoral arterial (SFA) access for coronary angiography and provisional PCI, as well as the most suitable guiding coronary catheters and angiographic projections for the above interventions. Experiments were performed under general anesthesia, using ultrasound-guided puncture of the SFA to gain arterial access. The Amplatzer AR1® catheter, and the Right Coronary Bypass® catheter were used for the selective engagement of the right and the left coronary artery, respectively. Successful arterial access and subsequent cardiac catheterization were performed in all pigs. Only one animal required a second puncture for femoral artery access. None of the 9 animals presented any significant tachycardia or hypotensive episode. One animal developed an access site-related complication following the first catheterization procedure. During follow-up, 100% success of SFA catheterization was achieved using the same ultrasound-guided technique. The ultrasound-guided superficial femoral artery access for coronary angiography and provisional interventions in porcine models is a quick and safe alternative to the carotid artery approach. The RCB and AR1 catheters may be the best choice for the quick and easy selective coronary engagement of the right and left ostia, respectively. © 2022, The Author(s)

Optical characteristics of ZnCuInS/ZnS (Core/shell) nanocrystal flexible films under X-ray excitation

The aim of this article is to evaluate optical characteristics, such as the intrinsic conversion efficiency and the inherent light propagation efficiency of three polymethyl methacrylate (PMMA)/methyl methacrylate (MMA) composite ZnCuInS/ZnS (core/shell) nanocrystal flexible films. The concentrations of these were 100 mg/mL, 150 mg/mL, and 250 mg/mL, respectively. Composite films were prepared by homogeneously diluting dry powder quantum dot (QD) samples in toluene and subsequently mixing these with a PMMA/MMA polymer solution. The absolute luminescence efficiency (AE) of the films was measured using X-ray excitation. A theoretical model describing the optical photon propagation in scintillator materials was used to calculate the fraction of the generated optical photons passed through the different material layers. Finally, the intrinsic conversion efficiency was calculated by considering the QD quantum yield and the optical photon emission spectrum. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Increased Body Mass Index (BMI) and Sunscreen Use Are Associated with Inadequate Vitamin D Status in Greek Adults in Winter: BMI, Sunscreen Use and Vitamin D Status in Greek Adults

Vitamin D deficiency is common even in sunny countries like Greece, especially during winter and is associated with skeletal disorders and additionally with increased risk for chronic diseases and adipose metabolic diseases such as obesity and diabetes. The purpose of this pilot study was the determination of vitamin D status in Greek adults and the investigation of possible correlation with lifestyles and somatometric characteristics. The study was conducted during winter and included 36 members (20 women and 16 men) of a university community in central Greece (latitude 39.6° North). Their age was 36.2 ± 16.3 years, body mass index (BMI) 26.4 ± 4.8 (women 26.6 ± 5.6, men 26.3 ± 3.8), and waist circumference 85.7 ± 13.3 cm (women 81.5 ± 13.0, men 90.7 ± 12.4) (mean ± SD). Mean serum 25(OH)D concentration was 20.1 ± 7.3 ng/mL (women 19.7 ± 7.6, men 20.7 ± 7.1). More than half of the participants had 25(OH)D levels below the 20 ng/mL (50 nmol/L) threshold of deficiency. There was a significant negative association between the use of sunscreen during summer and serum 25(OH)D concentrations during winter and a significant positive association between physical exercise and serum 25(OH)D. Levels of 25(OH)D tended to decrease with increasing BMI in persons with a BMI over 25.0. There is a high prevalence of vitamin D insufficiency in Greek adults during winter. Serum 25(OH)D levels in winter are positively associated with exercise and negatively associated with high BMI and the use of sunscreen during summer. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG