Impaired Left Ventricular Global Longitudinal Strain among Patients with Chronic Kidney Disease and End-Stage Renal Disease and Renal Transplant Recipients

Background: Although heart failure is the most prevalent cardiovascular disease associated with adverse outcome in chronic kidney disease (CKD) and after kidney transplantation, left ventricular (LV) systolic function is often preserved in renal patients. The aim of this study was to evaluate global longitudinal strain (GLS), which is reportedly a more accurate tool for detecting subclinical LV systolic dysfunction, in patients with various degrees of renal function impairment, including kidney transplant recipients (KTRs). Methods: This prospective study evaluated demographic, clinical, and ultrasound data, including the assessment of LV GLS and mitral E peak velocity and averaged ratio of mitral to myocardial early velocities (E/e'), of 70 consecutive renal patients (20 with stage 2-4 CKD, 25 with end-stage renal disease on hemodialysis [HD], and 25 KTRs). All patients had an LV ejection fraction 6550% and no history of heart failure or coronary artery disease. We used multivariable logistic analysis to assess the risk of compromised GLS. One hundred and twenty control subjects with or without hypertension served as controls. Results: A compromised GLS <-18% was shown in 55% of patients with stage 2-4 CKD, 60% of HD patients, and 28% of KTRs, while it was 32% in hypertensive controls and 12% in non-hypertensive controls (p < 0.0001). Patients with HD had higher systolic pressure and a significantly greater prevalence of increased LV mass and diastolic dysfunction. In renal patients, E/e' (p = 0.025), and LV mass index (p = 0.063) were independent predictors of compromised GLS at logistic regression analysis. E/e', systolic artery pressure, and LV mass also exhibited the greatest areas under the curve on receiver operating characteristic analysis to identify a compromised GLS. Conclusions: Renal disease proved to be associated with early and subclinical impairment of LV systolic function, which persists after starting dialysis and even in spite of successful kidney transplantation. An increased E/e' resulted to be the most powerful independent predictor of abnormal GLS

interazioni su nanoscala per una buona efficienza dei mezzi di contrasto

2009/2010Iopamidolo, Iomeprolo e Iopromide sono Mezzi di Contrasto Iodinati Non-ionici (MCIN) usati in urografia e angiografia come soluzioni concentrate. I dati relativi ai MCIN presenti in letteratura mostrano un’abbondanza di informazioni cliniche ma una carenza di dati riguardanti le loro caratteristiche chimico-fisiche. L’efficenza di questi composti in ambito medico è dovuta alla combinazione di tali proprietà. Risulta quindi necessario uno studio relativo ai dettagli molecolari per chiarire i contributi di ogni gruppo funzionale del sistema che determinano le differenze in termini di comportamento chimico-fisico. Le soluzioni concentrate di MCIN sono caratterizzate da bassi valori di viscosità e osmolalità dovuti all’autoassemblamento del sistema che genera aggregati nanostrutturati solubili in soluzione acquosa. Da queste considerazioni, questo lavoro di ricerca si è focalizzata su tecniche spettroscopiche, termodinamiche e di simulazioni di dinamica molecolare per indagare il fenomeno dell’associazione, sia in funzione della temperatura che della concentrazione, relazionato alle interazioni intermolecolari che spesso sono la principale causa della stabilità delle soluzioni concentrate di MCIN. Questi composti possiedono una struttura molecolare relativamente semplice, ma sono sistemi complessi in quanto soggetti all’atropisomerismo che causa la coesistenza di isomeri strutturali (atropisomeri) in soluzione, quindi di diverse geometrie di interazione soluto-soluto. Il primo approccio sperimentale è stata la caratterizazione molecolare attraverso la spettroscopia NMR per determinare gli equilibri conformazionali in termini di percentuali di popolazione in soluzione. Studi termodinamici hanno permesso di classificare Iopamidolo, Iomeprolo e Iopromide in base alle loro caratteristiche idrofiliche ed idrofobiche nei confronti delle molecole di acqua. Parallelamente sono state realizzate simulazioni di dinamica molecolare per ottenere informazioni riguardo la sfera di idratazione (confrontate con i dati termodinamici da letteratura) e sul processo di associazione che è stato studiato in funzione della temperatura sia con la spettroscopia NMR che con quella Brillouin. Ulteriori informazioni sulle interazioni intermolecolari e sull’atropisomerismo sono state ottenute analizzando anche lo stato solido dello Iopamidolo e dello Iomeprolo (sia sui vetri che sui cristalli) tramite tecniche spettroscopiche, calorimetriche e diffrattometriche i cui risultati hanno mostrato analogie in termini di interazioni intermolecolari fra le catene laterali. Inoltre, studi in funzione della temperatura hanno mostrato alcune transizioni solido-solido. L’accumulo di dati sperimentali relativi alla calorimetria isoterma e a scansione, traiettorie di dinamica molecolare ed alle varie spettroscopie, ha permesso di estendere il quadro generale delle conoscenze delle proprietà chimico-fisiche dei MCIN.Iopamidol, Iomeprol and Iopromide are Non-ionic Iodinated Contrast Media (NICMs) are used as concentrated solutions in x-Ray diagnostics as angiography and urography. The analysis of the current literature knowledge on NICMs shows an clear abundance of clinical diagnosis data but a lack of information on their physico-chemical properties. The success of these molecules in diagnosis is due to a combination of their properties, but a clarification of the role of structural determinants affecting the processes in concentrated solution is necessary. Thus a study of the molecular details may shed light on the differences in physico-chemical behavior. The concentrated solutions of NICMs are characterize by low viscosity and osmolality values due to the self-assembling of the system that generates soluble nano-structured aggregates in aqueous solution. Standing these considerations, the research work focused on spectroscopic, thermodynamics and MD simulation techniques to probe the association phenomenon, as a function of concentration and temperature. The interplay of the intermolecular interactions are the main reason for the stability of the concentrated solution of NICMs. Non-ionic iodinated contrast media have quite a simple molecular structure, but they show a complex behaviour due to the atropisomerism phenomenon. The coexistence of several structural isomers (atropisomers) in solution is at the basis of the different geometries of solute-solute interasctions. Thus, the first study whas been the molecular characterization of these molecules by using NMR spectroscopy to probe the conformational equilibria in terms of conformer population in solution. Thermodynamic approaches provided a classification of Iopamidol, Iomeprol and Iopromide according to their thermodynamics behaviour in terms of hydrophilic and hydrophobic interactions with water molecules. In parallel, MD simulations data were carried out to provide information about hydration shell (which were compared with experimental data from literature) and aggregation process. Similarly, the association was probed by both NMR and experimental thermodynamic data. To have more information on the nature of intermolecular interactions and atropisomerism phenomenon the solids of Iomeprol and Iopamidol (either or glasses and crystals) were analyzed by spectroscopic, calorimetric and diffractometric techniques that shown agreement in terms of intermolecular interactions among side chains. Furthemore, solid-solid transitions were detected as a function of temperature. By collecting experimental data by isothermal and scanning calorimetry, thermodynamic properties, molecular dynamics simulations and expecially by several spectroscopics methods a choerent description of the structure and dynamics of NICMs has been achieved. These results provide new knowledge on thier physico-chemical properties and allow us to interpret some anclear phenomena.XXIII Ciclo198

Thermal degradation of EDC-crosslinked dentinal collagen in alcoholic solution

Purpose: 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) is used to crosslink the collagen contained in dentin. The aim of this preliminary study was to detect the cross-linking reaction promoted by EDC from 10 min to 60 min in two different solutions (absolute EtOH) by measuring the thermal degradation temperature (TDT) of human dentin collagen. The null hypothesis tested was that no differences would have been found among the untreated dentin collagen and the EDC-treated specimens. Methods and materials: 15 dentin slabs (1 mm thick, 6 mm diameter) were completely demineralized in 10%H3PO4 solution and washed in MilliQ water in agitation for at least 24 h. A Fourier transform infrared (FTIR) spectroscopy analysis of each slab confirmed the absence of mineral. Each demineralized slab was radially sectioned in 6 specimens 1 mm 7 1 mm 7 1 mm and dried in anhydrous atmosphere with SiO2. 6 specimens of each slab were immersed in the assigned EDC ethanol solution (0.5 M or 1 M) for 10, 20, 30, 40, 50 or 60 min (T10, T20, T30, T40, T50, T60 respectively), rinsed for 15 min in demineralized water under agitation, dehydrated and analyzed with the DSC (DSC, Q10 TA Instruments) to obtain the TDT of EDC-treated collagen. One repetition for each test condition was made. All data were statistically analyzed (Kruskal\u2013Wallis and Mann\u2013Whitney tests). Results: The thermal degradation temperatures of untreated and EDC-treated dehydrated dentin collagen are shown in the table below (\ub0C, mean). No statistical differences were found. Conclusion: EDC-treated dentin collagen did not show a higher TDT than the untreated control irrespective of concentration and time of application, thus the test fail to reject the null hypothesis. An improved TDT is an indirect indicator of a more resistant and highly cross-linked collagen network. More data are needed to confirm these preliminary results

Effect of lithium disilicate veneers of different thickness on the degree of conversion and microhardness of a light-curing and a dual-curing cement

7noPurpose: Various materials and systems for bonding lithium disilicate to the tooth substrate are available to clinicians, who can adapt the materials to each clinical situation to maximize the performance of indirect esthetic restorations. This study aimed to evaluate the degree of conversion (DC) and the microhardness (MH) of a dual-curing and a light-curing cement under lithium disilicate discs of different thicknesses. Materials and Methods: A total of 48 lithium disilicate (IPS e.max CAD, Ivoclar Vivadent) samples were prepared and divided into three groups (n = 16) according to the thickness (group A was 0.6 mm; group B was 1.0 mm; group C was 1.5 mm). Each group was further divided into two subgroups (n = 8) according to the resin cement employed, NX3 (Kerr) or Choice 2 (Bisco). A standardized quantity of cement was placed on the sample, and DC was evaluated with an attenuated total reflectance Fourier transformed infrared spectrophotometer (Nicolet IS10, Thermo Scientific). Twenty-four hours after DC was established, Vickers test was performed on the cement with a microindentometer (Leica Microsystems). Results were statistically analyzed with analysis of variance test and significance set at P < .05. Results: Statistical analysis showed cement type had a significant influence (P = .005) on DC. MH results were influenced by thicknesses only between 0.6 and 1.5 mm when light-cured cement was employed. Conclusion: The light-curing and the dualcuring cements reached comparable DCs between 0.6 and 1.5 mm. However, the light-curing resin showed a higher DC and MH.reservedmixedScotti, Nicola; Comba, Allegra; Cadenaro, Milena; Fontanive, Luca; Breschi, Lorenzo; Monaco, Carlo; Scotti, RobertoScotti, Nicola; Comba, Allegra; Cadenaro, Milena; Fontanive, Luca; Breschi, Lorenzo; Monaco, Carlo; Scotti, Robert

Degree of conversion of self-etch adhesives: In situ Micro-Raman analysis

Purpose: Degree of conversion (DC) affects the physicochemical properties of dental adhesives. The aim of this study was to measure the DC within the hybrid layer of four one-step self-etch adhesives using Raman microspectroscopy. The hypothesis tested was that there was no difference among the tested adhesives. Methods and Materials: The selected one-step self-etch adhesives (Clearfil S3 Bond Plus, IBOND, G-BOND, and Adper Easy Bond) were applied on human dentin disks and polymerized in accordance with the manufacturers' instructions. Specimens were transversally cut to expose the bonded interfaces to the micro- Raman beam, and Raman spectra were collected along the dentin/adhesive interface. Measurements were performed at 1-lm intervals. The relative intensities of bands associated with the C=C bond (at 1640 cm-1) and an internal stable peak (1610 cm-1) were determined to calculate the degree of conversion within the hybrid layer. Data were statistically analyzed with Kolmogorov-Smirnov and Bartlett tests and Kruskal-Wallis and Mann-Whitney U-tests. Results: The DC ranked as follows: G-BOND (93%\ub16%) Adper Easy Bond (92%\ub16%) 65IBOND (89%\ub17%). Clearfil S3 Bond Plus (80%\ub114%) (p<0.05). Conclusions: Based on the results of this study, all of the tested self-etch adhesives showed a clinically acceptable DC that was material dependent

Thermal degradation of EDC-cross-linked dentinal collagen

Purpose: 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) has been shown to cross-link type I collagen, in dentin. The aim of this preliminary study was to detect the cross-linking reaction promoted by EDC in different aqueous solutions by measuring the thermal degradation temperature (TDT) of human dentin collagen over time. The null hypothesis tested was that no differences would have been found among the untreated dentin collagen and the EDC-treated specimens. Methods and materials: 3 dentin slabs (1 mm thick, 6 mm diameter) were completely demineralized in 10% H3PO4 solution and washed in MilliQ water in agitation for at least 24 h. A Fourier transform infrared (FTIR) spectroscopy analysis of each slab confirmed the absence of mineral. Each demineralized slab was radially sectioned in 7 specimens 1 mm 7 1 mm 7 1 mm and dried in anhydrous atmosphere with SiO2. For each slab 1 specimen was analyzed with a differential scanning calorimeter (DSC, Q10 TA Instruments) to obtain the TDT of dehydrated collagen. The other 6 specimens of each slab were immersed in the assigned EDC aqueous solution (0.1 M, 0.5 M or 1 M) for 10, 20, 30, 40, 50 or 60 min (T10, T20, T30, T40, T50, T60 respectively), rinsed for 15 min in demineralized water under agitation, dehydrated and analyzed with the DSC to obtain the TDT of EDC-treated collagen. All data were statistically analyzed (Kruskal\u2013Wallis test, Mann\u2013Whitney test). Results: The thermal degradation temperatures of untreated and EDC-treated dehydrated dentin collagen are shown in the table below. No statistical differences were found. Conclusion: EDC-treated dentin collagen did not show a higher TDT than the untreated control irrespective from concentration and time of application, thus the null hypothesis was confirmed. An improved TDT is an indirect indicator of a more resistant and highly cross-linked collagen network. More data are needed to confirm these preliminary results and further studies are necessary to define the role of EDC in collagen reinforcement strategies. This study was supported by FIRB RBAP1095CR, PRIN 2009SAN9K5 and 2009FXT3WL of MIUR and by R01 DE015306 from the NIDCR to DHP (PI)

Occlusal loading and cross-linking effects on dentin collagen degradation in physiological conditions

Objective This study evaluated the ability of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) to improve the stability of demineralized dentin collagen matrices when subjected to mechanical cycling by means of Chewing Simulation (CS). Methods Demineralized dentin disks were randomly assigned to four groups (N = 4): (1) immersion in artificial saliva at 37 \ub0C for 30 days; (2) pre-treatment with 0.5 M EDC for 60 s, then stored as in Group 1; (3) CS challenge (50 N occlusal load, 30 s occlusal time plus 30 s with no load, for 30 days); (4) pre-treatment with 0.5 M EDC as in Group 2 and CS challenge as in Group 3. Collagen degradation was evaluated by sampling storage media for ICTP and CTX telopeptides. Results EDC treated specimens showed no significant telopeptides release, irrespective of the aging method. Cyclic stressing of EDC-untreated specimens caused significantly higher ICTP release at day 1, compared to static storage, while by days 3 and 4, the ICTP release in the cyclic group fell significantly below the static group, and then remained undetectable from 5 to 30 days. CTX release in the cyclic groups, on EDC-untreated control specimens was always lower than in the static group in days 1-4, and then fell to undetectable for 30 days. Significance This study showed that chewing stresses applied to control untreated demineralized dentin increased degradation of collagen in terms of CTX release, while collagen crosslinking agents may prevent dentin collagen degradation, irrespective of simulated occlusal function

Effect of carboidiimide on thermal denaturation temperature of dentin collagen

1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) has been shown to cross-link dentin type I collagen. Increased cross-linking usually elevates the glass transition temperature of polymers. The aim of this study was to evaluate the cross-linking reaction promoted by EDC in different aqueous concentrations by measuring the thermal denaturation temperature (Td) of human dentin collagen

Myelography iodinated contrast media. I. unraveling the atropisomerism properties in solution

The present work reports a thorough conformational analysis of iodinated contrast media: iomeprol, iopamidol (the world\u2019s most utilized contrast agent), and iopromide. Its main aim is the understanding of the complex structural features of these atropisomeric molecules, characterized by the presence of many conformers with hindered rotations, and of the role of atropisomerism in the physicochemical properties of their aqueous solutions. The problem was tackled by using an extensive analysis of 13C NMR data on the solutions of whole molecules and of simple precursors in addition to FT-IR investigation and molecular simulations. This analysis demonstrated that out of the many possible atropisomers, only a few are significantly populated, and their relative population is provided. The conformational analysis also indicated that the presence of a sterically hindered amidic bond, allowing a significant population of cis forms (E in iopromide and exo in iomeprol), may be the basis for an increased thermodynamic solubility of concentrated solutions of iomeprol