Vibrational analysis and structural implications of H-bonding in isolated and aggregated 2-amino-1-propanol: a study by MI-IR and Raman spectroscopy and molecular orbital calculations

Isolated 2-amino-1-propanol (2AP) was studied by matrix-isolation infrared spectroscopy (MI-IR) in Ar and Kr and ab initio 6-31G* calculations undertaken at the HF-SCF and MP2 levels of theory. For the first time, five different conformational states of 2AP could be experimentally observed, which could be correlated with the most stable forms predicted by the calculations. The first and second lowest energy forms correspond to conformers which exhibit a considerably strong intramolecular OH...N hydrogen bond (g'Gg' and gG'g), while the less abundant forms observed in the matrices (gGg', gGt and g'G'g) are characterized by having a weak intramolecular NH...O or OH...N bond. These results were reinforced by infrared solution studies of the compound in tetrachloromethane and tetrachloroethylene. The experimental data obtained for the pure liquid, where OH...N intermolecular hydrogen bonding dominates, indicate that the preferred conformation of the monomeric unit within the aggregates is similar to conformer gGt.http://www.sciencedirect.com/science/article/B6TGS-415RNK9-11/1/bc743f78fe244248cd0deab43f33534

Low temperature polymorphism in 3-amino-1-propanol

3-Amino-1-propanol (3AP) was investigated by differential scanning calorimetry, and low temperature powder X-ray diffraction and Raman spectroscopy. Within the range of temperatures studied (-150-25 °C), 3AP was found to be able to crystallize in two monotropic polymorphs. Fast cooling rates produce an amorphous state that, on heating, crystallizes into the metastable polymorph. At higher temperatures, this metastable crystalline phase converts into the stable crystal. Using intermediate cooling rates, 3AP crystallizes as the metastable polymorph, the solid[right triple arrow]solid transition leading to conversion of this form into the stable polymorph occurring during the subsequent heating. Slower cooling rates enable formation of the stable crystal on cooling. The two crystalline polymorphs were structurally characterized by powder X-ray diffraction and Raman spectroscopy. It was concluded that different conformations are assumed by the individual molecules of 3AP in the two crystalline varieties, with the molecules assuming the all-trans configuration in the metastable crystalline state and having the heavy atom backbone trans but the NH2 and OH groups gauche in the stable crystal.http://www.sciencedirect.com/science/article/B6TGS-481FSJV-2/1/6d44932042d3990f18c7e3cb071cddf

Structural and vibrational characterisation of 3-amino-1-propanol a concerted SCF-MO ab initio, Raman and infrared (matrix isolation and liquid phase) spectroscopy study

Results obtained for the isolated and liquid 3-amino-1-propanol by a concerted molecular orbital and vibrational spectroscopic approach are reported. The relative energies and both structural and vibrational data of the different conformers of the studied compound were calculated using the extended 6-31G* basis set both at the HF-SCF and MP2 ab initio levels of theory and the theoretical results used to interpret Raman and infrared experimental data. In the gaseous phase and for the molecule isolated in an Argon matrix, monomeric 3-amino-1-propanol exists as a mixture of conformers, the first and second lowest energy forms corresponding to conformers which exhibit an intramolecular OH---N hydrogen bond (forms I and II). On the other hand, in the pure liquid, where intermolecular H-bonding occurs, the monomeric unit within the aggregates assumes a conformation similar to that of the third most stable form found for the isolated molecule situation (form III), which is characterised by having a weak intramolecular NH---O bond. The experimental data obtained for the pure liquid also reveals the presence of monomeric form I in this phase, a result that is in consonance with the strongly stabilizing OH---N intramolecular hydrogen bond that is present in this conformer.http://www.sciencedirect.com/science/article/B6VNG-402TR9Y-3/1/4d2e96a2fd7da2d70b63b1e0a45769c

Corações “Fora do Prazo”: Dois Casos de Amiloidose AL

A amiloidose cardíaca é considerada uma doença rara e classicamente descrita como de mau prognóstico, com sobrevivência média de seis meses, desde a instalação da sintomatologia de insuficiência cardíaca. Quando há suspeita  de amiloidose cardíaca está indicado o estudo etiológico, para caracterização do tipo de proteína implicada, bem como a avaliação do atingimento de outros órgãos. Neste artigo, os autores relatam dois casos, diagnosticados e tratados no Hospital CUF Descobertas (HCD) - em colaboração com o Instituto Português de Oncologia de Lisboa (IPOL) e o National Amyloidosis Centre (NAC), Londres - de insuficiência cardíaca por amiloidose AL associada a gamapatia monoclonal. Atualmente os doentes mantêm seguimento no HCD e apresentam-se clinicamente bem. Recebido: 02/05/2017 - Aceite: 18/08/201

A combined matrix-isolation infrared spectroscopy and MO study of 1-amino-2-propanol

Vibrational spectra of 1-amino-2-propanol (1AP) isolated in argon and krypton matrices at 14 K and of the pure liquid at room temperature were recorded and interpreted on the basis of ab initio MO calculations undertaken at the HF-SCF and MP2 levels of theory. For the first time, five different conformational states of monomeric 1AP could be experimentally observed and their vibrational signatures obtained. The observed conformers were found to correlate well with the most stable forms predicted by the MP2 calculations, the first and second lowest energy forms corresponding to conformers which exhibit a considerably strong intramolecular OH...N hydrogen bond (gG'g and g'Gg'), while the less abundant forms observed in the matrices (tG't, g'G't and tG'g') are characterized by having a relatively weak intramolecular NH...O bond. These results were reinforced by infrared solution studies of the compound in tetrachloroethylene. The experimental data obtained for the pure liquid, where OH...N intermolecular hydrogen bonding dominates, indicate that the preferred conformation of the monomeric unit within the aggregates is similar to conformer tG't.http://www.sciencedirect.com/science/article/B6THW-4378TW2-D/1/882ed76574dfb8ce4839bb30bb51178

Thermal study of simple amino-alcohol solutions

Widely regarded as the most promising approach to long-term cryopreservation of organs for transplantation, vitrification is a process where liquid is transformed into a disordered solid state free from crystals, known as the amorphous state. The vitreous state is obtained by rapid cooling to cryogenic temperatures in the presence of antifreeze substances called cryoprotectants, such as polyalcohols, which are known to be very good vitrification agents. This work reports on the thermal properties of a new class of compounds, the amino-alcohols, studied for its similarity to the structure of the equivalent polyalcohols. We studied by differential scanning calorimetry the glass-forming tendency and stability of the amorphous state for de-ionized water solutions containing 2-amino-1-ethanol and 3-amino-1-propanol at the concentrations of 35%, 40%, 43%, and 45% (w/w). A comparison is made with previous results obtained by Mehl [Cryobiology 27 (1990) 687–688] on the same compounds under different experimental conditions. The results are also compared with those obtained by Boutron [Cryobiology 30 (1993) 87–97] for the corresponding dialcohols. A further comparison is made with a few results obtained for the 1-amino-2-propanol and the 2-amino-1-propanol tested under the same condition

Short and long-term clinical impact of transcatheter aortic valve implantation in Portugal according to different access routes: Data from the Portuguese National Registry of TAVI

Introduction: The Portuguese National Registry of Transcatheter Aortic Valve Implantation records prospectively the characteristics and outcomes of transcatheter aortic valve implantation (TAVI) procedures in Portugal. Objectives: To assess the 30-day and one-year outcomes of TAVI procedures in Portugal. Methods: We compared TAVI results according to the principal access used (transfemoral (TF) vs. non-transfemoral (non-TF)). Cumulative survival curves according to access route, other procedural and clinical variables were obtained. The Valve Academic Research Consortium-2 (VARC-2) composite endpoint of early (30-days) safety was assessed. VARC-2 predictors of 30-days and 1-year all-cause mortality were identified. Results: Between January 2007 and December 2018, 2346 consecutive patients underwent TAVI (2242 native, 104 valve-in-valve; mean age 81±7 years, 53.2% female, EuroSCORE-II - EuroS-II, 4.3%). Device success was 90.1% and numerically lower for non-TF (87.0%). Thirty-day all-cause mortality was 4.8%, with the TF route rendering a lower mortality rate (4.3% vs. 10.1%, p=0.001) and higher safety endpoint (86.4% vs. 72.6%, p5% (p<0.001) and who underwent non-TF TAVI (p<0.001). Conclusion: Data from our national real-world registry showed that TAVI was safe and effective. The use of a non-transfemoral approach demonstrated safety in the short term. Long-term prognosis was, however, adversely associated with this route, with comorbidities and the baseline clinical status.info:eu-repo/semantics/publishedVersio

Yield of contemporary clinical strategies to detect patients with obstructive coronary artery disease

Purpose Noninvasive ischemia testing (NIST) is recommended for most patients suspected to have stable coronary artery disease (CAD) before invasive coronary angiography (ICA). We sought to assess the diagnostic predictive ability of NIST over clinical risk profiling in a contemporary sample of patients undergoing the currently recommended diagnostic triage strategy. Methods From 2006 to 2011, 2,600 consecutive patients without known CAD undergoing elective ICA in a single tertiary-care center were retrospectively identified and the prevalence of obstructive CAD determined. To understand the incremental value of frequently used clinical parameters in predicting obstructive CAD, receiver operating characteristic curves were plotted for six sequential models starting with Framingham risk score and then progressively adding multiple clinical factors and finally NIST results. Results At ICA 1,268 patients (48.8%) had obstructive CAD. The vast majority (85%) were classified in an intermediate clinical pretest probability of CAD and NIST prior to ICA was used in 86% of the cohort. The most powerful correlate of obstructive CAD was the presence of severe angina (odds ratio (OR) = 9.1; 95% confidence interval (CI) 4.3-19.1). Accordingly, the incorporation of NIST in a sequential model had no significant effect on the predictive ability over that achieved by clinical and symptomatic status model (C-statistic 0.754; 95% CI 0.732-0.776, p = 0.28). Conclusions Less than half the patients with suspect stable obstructive CAD referred to a tertiary-level center for elective ICA had the diagnosis confirmed. In this clinical setting, the results of NIST may not have the power to change the discriminative ability over clinical judgment alone

Permanent pacemaker implantation after alcoholic septal ablation induced complete heart block: Long-term impact

Introduction and objectives: Patients with hypertrophic obstructive cardiomyopathy (HOCM) that remain symptomatic despite optimized medical therapy often undergo alcohol septal ablation (ASA). One of the most frequent complications is complete heart block (CHB), requiring a permanent pacemaker (PPM) in variable rates of up to 20% of patients. The long-term impact of PPM implantation in these patients remains unclear. This study aimed to evaluate the long-term clinical outcomes in patients who implant PPM after ASA. Methods: Patients who underwent ASA at a tertiary center were consecutively and prospectively enrolled. Patients with previous PPM or implantable cardio-defibrillator were excluded from this analysis. Patients with and without PPM implantation after ASA were compared based on their baseline characteristics, procedure data and three-year primary endpoint of composite of all-cause mortality and hospitalization and secondary endpoint of composite of all-cause mortality and cardiac cause hospitalization. Results: Between 2009 and 2019, 109 patients underwent ASA, 97 of whom were included in this analysis (68% female, mean age 65.2 years old). 16 patients (16.5%) required PPM implantation for CHB. In these patients, no vascular access, pacemaker pocket or pulmonary parenchyma complications were noted. The baseline characteristics of comorbidities, symptoms, echocardiographic and electrocardiographic findings were identical in the two groups, with higher mean age (70.6±10.0 years vs. 64.1±11.9 years) and lower beta-blocker therapy rate (56% vs. 84%) in the PPM group. Procedure-related data showed higher creatine kinase (CK) peaks in the PPM group (1692 U/L vs. 1243 U/L), with no significant difference in the alcohol dose. At three years after ASA procedure, there were no differences in the primary and secondary endpoints between the two groups. Conclusions: Permanent pacemaker after ASA induced CHB do not affect long term prognosis in hypertrophic obstructive cardiomyopathy patients. Resumo: Introdução e objetivos: Doentes com miocardiopatia hipertrófica obstrutiva (MCHO) sintomáticos apesar de terapêutica médica otimizada são frequentemente submetidos a ablação septal alcoólica (ASA). O bloqueio atrioventricular (BAV) completo é uma complicação frequente, requerendo implantação de pacemaker definitivo em taxas variáveis que podem ir até 20% dos doentes. O impacto a longo prazo da implantação de pacemaker nestes doentes permanente mal-esclarecido. Esta análise pretende avaliar os outcomes clínicos a longo prazo nestes doentes. Métodos: Doentes consecutivos submetidos a ASA num centro terciário foram incluídos e seguidos prospetivamente. Pacientes com pacemaker ou cardiodesfibrilhador prévio foram excluídos desta análise. Os doentes com e sem implantação de pacemaker após a ASA foram caracterizados e comparados relativamente aos endpoints primário (composto de mortalidade e hospitalização por todas as causas) e secundário (composto de mortalidade por todas as causas e hospitalização de causa cardíaca) a três anos. Resultados: Entre 2009 e 2019, 109 pacientes foram submetidos a ASA e 97 foram incluídos nesta análise (68% sexo feminino, idade media 65,2 anos). Implantaram pacemaker 16 doentes (16,5%) após a ASA por BAV completo. Não se registaram complicações vasculares, da loca ou parenquimatosas pulmonares. As características basais foram semelhantes entre os grupos, com maior idade média (70,6 ± 10,0 anos versus 64,1 ± 11,9 anos) e menor taxa de terapêutica beta-bloqueante (56% versus 84%) no grupo de pacemaker. Dados do periprocedimento revelaram maior pico de creatina cinase (CK) no grupo de pacemaker, sem diferença na dose de álcool usado. Aos três anos, os endpoints primário e secundário não mostraram diferenças entre os dois grupos. Conclusão: A implantação de pacemaker definitivo por BAV completo induzido por ablação septal alcoólica não afeta o prognóstico de pacientes com MCHO