RESUMEN

The development of higher-order cycloadditions has mainly been restricted by the requisite usage of highly conjugated and reactive π-systems. Recent years have witnessed organocatalysis as a potent mediator for several of the challenges associated herein, rendering higher-order cycloadditions a legitimate option for achieving the selective construction of specific molecular scaffolds. These developments reinvigorate the efforts to try to understand the underlying principles for cycloadditions involving a higher number of π-electrons than the "classical" cycloadditions; how do we properly address the impact which the addition of further π-electrons have on the reactivity of a system? Herein, computational investigations of two model higher-order cycloaddition systems have been performed to try to provide insights on changes in energetic barriers induced by the presence of benzofusions in a position which is unobstructive to the reactivity. With experimental substantiation as support, these studies might open up for a discussion on whether the π-electrons of benzofused systems simply act as spectator electrons, or play a tangible role on the observed reactivity to an extent where a distinct nomenclature is meritable.

RESUMEN

Mean arterial pressure (MAP) is often estimated from cuff systolic (S) and diastolic (D) blood pressure (BP) using a fixed arterial form factor (FF, usually 0.33). If MAP is measured directly, a true FF can be calculated: FF = [MAP-DBP]/[SBP-DBP]. Because waveform shapes vary, true FF should also vary and MAP accuracy will be affected. We studied factors affecting FF using radial tonography (SphygmoCor, n = 376) or brachial oscillometry (Mobil-O-Graph, n = 157) and to compare devices, 101 pairs were matched precisely for SBP and DBP. SphygmoCor brachioradial FF correlated strongly with central FF (r2 = 0.75), central augmentation index (cAI, r2 = 0.39), and inversely with pulse pressure amplification (PPA) ratio (r2 = 0.44) [all p < 0.000]; brachioradial FF was lower than central (c) FF (0.34 vs. 0.44, 95% CI's [0.23,0.46] and [0.34,0.54], p < 0.000). On forward stepwise regression, brachioradial FF correlated with PPA ratio, age, heart rate, and cAI (multiple-r2 0.63, p < 0.000). With Mobil-O-Graph: brachial FF was fixed, lower than the corresponding cFF [mean(SD)] 0.46(0.00098) vs. 0.57(0.048), p < 0.000], and uncorrelated with clinical characteristics; MAP and cSBP were higher than SphygmoCor by 6.3 and 2.2 mmHg (p < 0.005) at the midpoint with systematic negative biases. We conclude that FF derived from radial tonometry (SphygmoCor) varies with pulse wave morphology within and between individuals and by measurement site, age, and heart rate. With oscillometry (Mobil-O-Graph), brachial FF was fixed and high and unrelated to other clinical variables; MAP and cSBP were higher than tonometry, with systematic negative biases.

Asunto(s)

Presión Arterial , Determinación de la Presión Sanguínea , Humanos , Presión Sanguínea/fisiología , Arteria Braquial/fisiología , Frecuencia Cardíaca

RESUMEN

Nonbiaryl atropisomers are molecules defined by a stereogenic axis featuring at least one nonarene moiety. Among these, scaffolds bearing a conformationally stable C(sp2)-C(sp3) stereogenic axis have been observed in natural compounds; however, their enantioselective synthesis remains almost completely unexplored. Herein we disclose a new class of chiral C(sp2)-C(sp3) atropisomers obtained with high levels of stereoselectivity (up to 99% ee) by means of an organocatalytic asymmetric methodology. Multiple molecular motifs could be embedded in this class of C(sp2)-C(sp3) atropisomers, showing a broad and general protocol. Experimental data provide strong evidence of the conformational stability of the C(sp2)-C(sp3) stereogenic axis (up to t1/225 °C >1000 y) in the obtained compounds and show kinetic control over this rare stereogenic element. This, coupled with density functional theory calculations, suggests that the observed stereoselectivity arises from a Curtin-Hammett scenario establishing an equilibrium of intermediates. Furthermore, the experimental investigation led to evidence of the operating principle of central-to-axial chirality conversions.

RESUMEN

Experimental and theoretical 13C kinetic isotope effects (KIEs) are utilized to obtain atomistic insight into the catalytic mechanism of the Pd(PPh3)4-catalyzed Suzuki-Miyaura reaction of aryl halides and aryl boronic acids. Under catalytic conditions, we establish that oxidative addition of aryl bromides occurs to a 12-electron monoligated palladium complex (Pd-(PPh3)). This is based on the congruence of the experimental KIE for the carbon attached to bromine (KIEC-Br = 1.020) and predicted KIEC-Br for the transition state for oxidative addition to the Pd(PPh3) complex (1.021). For aryl iodides, the near-unity KIEC-I of ~1.003 suggests that the first irreversible step in the catalytic cycle precedes oxidative addition and is likely the binding of the iodoarene to Pd(PPh3). Our results suggest that the commonly proposed oxidative addition to the 14-electron Pd(PPh3)2 complex can occur only in the presence of excess added ligand or under stoichiometric conditions; in both cases, experimental KIEC-Br of 1.031 is measured, which is identical to the predicted KIEC-Br for the transition state for oxidative addition to the Pd(PPh3)2 complex (1.031). The transmetalation step, under catalytic conditions, is shown to proceed via a tetracoordinate boronate (8B4) intermediate with a Pd-O-B linkage based on the agreement between an experimental KIE for the carbon atom involved in transmetalation (KIEC-Boron = 1.035) and a predicted KIEC-Boron for the 8B4 transmetalation transition state (1.034).

RESUMEN

INTRODUCTION: There is a growing burden of cardiovascular disease in low- and middle-income countries and assessment of cardiovascular health (CVH) may identify populations at risk for poor CVH. METHODS: Between July 2014 and August 2014, we performed a household survey from a convenience sample among adult community members in rural northern Haiti. We used a modified World Health Organization STEPwise approach to chronic disease questionnaire to capture self-reported data on tobacco, diet, physical activity, and diabetes, and measured blood pressure and body mass index. We used an adapted American Heart Association definition and thresholds for determining ideal, intermediate, and poor cardiovascular health. We used linear and logistic regression to examine associations between socio-demographic characteristics with CVH score and ideal CVH. RESULTS: Among 540 participants (mean [SD] age = 40.3 [17.1] years, 67% women), there was a high prevalence of poor CVH (n=476, 88.1%) compared with intermediate (n=56, 10.4%) and ideal (n=41, 7.6%) CVH. Ideal metrics for blood pressure (47%) and diet (26%) were least often met, while body weight (84%), physical activity (83%), and smoking (90%) were most often met. Men were associated with better CVH score (0.31, [0.04-0.59]; P=0.03), and being a farmer was associated with ideal CVH (P=0.006). CONCLUSION: In this community-based sample of a farming community in rural Haiti, very few adults had ideal CVH. Higher CVH score was associated with male sex, and farming as a primary occupation. Women and non-farmers may represent at-risk subgroups within this population. Blood pressure and diet may represent possible areas for improvement.

Asunto(s)

Técnicas de Diagnóstico Cardiovascular , Análisis de la Onda del Pulso , Presión Sanguínea , Oscilometría

RESUMEN

Isobenzopyrylium ions are unique, highly reactive, aromatic intermediates which are largely unexplored in asymmetric catalysis despite their high potential synthetic utility. In this study, an organocatalytic asymmetric multicomponent cascade via dienamine catalysis, involving a cycloaddition, a nucleophilic addition, and a ring-opening reaction, is disclosed. The reaction furnishes chiral tetrahydronaphthols containing four contiguous stereocenters in good to high yield, high diastereoselectivity (up to >20:1), and excellent enantioselectivity (93-98% ee). The obtained products are important synthetic intermediates, and it is demonstrated that they can be used for the generation of frameworks such as octahydrobenzo[h]isoquinoline and [2.2.2]octane scaffolds. Furthermore, mechanistic experiments involving oxygen-18-labeling studies and density functional theory calculations provide a vivid picture of the reaction mechanism. Finally, the bioactivity of 16 representative tetrahydronaphthol compounds has been evaluated in U-2OS cancer cells with some compounds showing a unique profile and a clear morphological change.

RESUMEN

Chiral phase-transfer catalysis provides high level of enantiocontrol, however no experimental data showed the interaction of catalysts and substrates. 1 H NMR titration was carried out on Cinchona and Maruoka ammonium bromides vs. nitro, carbonyl, heterocycles, and N-F containing compounds. It was found that neutral organic species and quaternary ammonium salts interacted via an ensemble of catalyst + N-C-H and (sp2 )C-H, specific for each substrate studied. The correspondent BArF salts interacted with carbonyls via a diverse set of + N-C-H and (sp2 )C-H compared to bromides. This data suggests that BArF ammonium salts may display a different enantioselectivity profile. Although not providing quantitative data for the affinity constants, the data reported proofs that chiral ammonium salts coordinate with substrates, prior to transition state, through specific C-H positions in their structures, providing a new rational to rationalize the origin of enantioselectivity in their catalyses.

Asunto(s)

Ésteres , Cetonas , Amidas , Catálisis , Compuestos de Amonio Cuaternario , Sales (Química) , Estereoisomerismo

RESUMEN

BACKGROUND: Treatment with sacubitril-valsartan reduces mortality and heart failure (HF) events in HF with reduced ejection fraction and may reduce HF hospitalization in women with HF with preserved ejection fraction. METHODS: EVALUATE-HF randomized 464 participants (109 women) with HF with reduced ejection fraction to sacubitril-valsartan or enalapril for 12 weeks. Documented left ventricular ejection fraction (LVEF) ≤0.40 within the prior 12 months was required, although core laboratory LVEF>0.40 was permitted. Assessments of aortic stiffness (pulse pressure and characteristic impedance, Zc) were performed at baseline and at trough and 4 hours postdose at weeks 4 and 12. RESULTS: In models of change from baseline adjusted for baseline value, treatment with sacubitril-valsartan produced greater overall reductions in mean arterial pressure (treatment group difference, -3.0±0.8 mm Hg, P<0.001) and pulse pressure (-3.0±0.8 mm Hg, P<0.001). Postdose reductions in Zc were greater in the sacubitril-valsartan group (-16±6 dyne×second/cm5, P=0.012). Post hoc analyses found evidence of effect modification by LVEF (interaction P=0.036). With LVEF<0.40, postdose reductions in Zc were greater in the sacubitril-valsartan group (trough, -3±8 dyne×second/cm5 versus post-dose, -17±8 dyne×second/cm5; interaction P=0.024) with no sex difference (treatment×sex interaction, P=0.3). With LVEF≥0.40, treatment with sacubitril-valsartan was associated with greater overall reductions in Zc in women (women, -80±21 dyne×second/cm5 versus men, -20±13 dyne×second/cm5; interaction P=0.019). CONCLUSIONS: In prespecified analyses that include pre- and postdose assessments at 4 and 12 weeks, treatment with sacubitril-valsartan was associated with greater postdose reductions in aortic Zc. In a post hoc analysis, sacubitril-valsartan was associated with sustained reductions in Zc in women with LVEF≥0.40. Registration: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT02874794.

Asunto(s)

Aminobutiratos/uso terapéutico , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Compuestos de Bifenilo/uso terapéutico , Enalapril/uso terapéutico , Insuficiencia Cardíaca/tratamiento farmacológico , Volumen Sistólico/fisiología , Valsartán/uso terapéutico , Rigidez Vascular/fisiología , Anciano , Combinación de Medicamentos , Modificador del Efecto Epidemiológico , Femenino , Insuficiencia Cardíaca/fisiopatología , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Resultado del Tratamiento

RESUMEN

BACKGROUND: Several previous studies have investigated the clinical utility of age-adjusted D-dimer cutoffs for diagnosing pulmonary embolism (PE). OBJECTIVES: We performed a pre/post implementation study, using data from a mid-Atlantic healthcare system comprising 6 hospitals and 400,000 ED visits to determine whether implementing age adjusted D-dimer cutoffs reduced the number of imaging tests performed. METHODS: Retrospective study of all patients who had a D-dimer performed during ED visits between September 2015 to September 2018. On March 21, 2017, the D-dimer upper limit of normal system-wide was increased for patients over 50 to: Age (years) x 0.01µg/mL. D-dimer results were displayed as normal or high based on automated age adjustment. EHR Chart review was performed 1.5 years prior to implementation of age-adjusted D-dimer cutoffs, as well as 1.5 years after to evaluate mortality and test accuracy characteristics such as false negative rates. Comparisons were made using chi-square testing. RESULTS: 22,302 D-dimers were performed pre-implementation of which 10,837 (48.6%) were positive resulting in 7218 (32.3%) imaging studies. After implementation of age-adjusted d-dimer, 25,082 were performed of which 10,851 (43.2%) were positive resulting in 7017 (28.0%) imaging studies. (pre: 48.6%, post: 43.2%; p < 0.01). A significantly lower proportion of patients had a positive d-dimer (pre: 48.6%, post: 43.2%; p < 0.01) and underwent imaging post-implementation (pre: 32.3%, post: 28.0%; p < 0.05) a relative risk reduction of 13.3. This absolute risk reduction of 4.4% is associated with 1104 less scans in the post-implementation group while still increasing test accuracy from 53.7% to 59.2% (p < 0.05). CONCLUSION: Implementation of an automated age-adjusted D-dimer positive reference value reduced CT and V/Q imaging in this population by 4.4% while increasing test accuracy in a regional, heterogeneous six-hospital system.

Asunto(s)

Productos de Degradación de Fibrina-Fibrinógeno/análisis , Embolia Pulmonar/sangre , Embolia Pulmonar/diagnóstico por imagen , Factores de Edad , Anciano , Registros Electrónicos de Salud , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Estudios Retrospectivos , Procedimientos Innecesarios

RESUMEN

The use of pseudo enantiomers is a well-known method of achieving products of complementary stereochemistry. Only rarely can different enantiomers of a product be accessed without modulation of the catalyst. Recently, a system was reported wherein two different enantiomers of spirocycles were obtained by a cascade reaction of unsaturated pyrrolin-4-ones with mercaptoacetaldehyde catalyzed by a single optimized cinchona alkaloid squaramide-derived organocatalyst. It was originally proposed that the E/Z geometry of the unsaturated pyrrolin-4-one dictated the stereochemistry of the spirocycle product, but this was not investigated further. In the present work, we have investigated the nature of a pseudo-enantiomeric organocatalyst conformation applying density functional theory calculations for investigating the transition states for the reaction. Furthermore, the influence of the double-bond geometry of the pyrrolin-4-one has been studied beyond what is possible to test experimentally. The results provide a greater understanding for this class of reactions that may be applicable in future methodology development.

RESUMEN

IMPORTANCE: Compared with enalapril, sacubitril-valsartan reduces cardiovascular mortality and heart failure hospitalization in patients with heart failure and reduced ejection fraction (HFrEF). These benefits may be related to effects on hemodynamics and cardiac remodeling. OBJECTIVE: To determine whether treatment of HFrEF with sacubitril-valsartan improves central aortic stiffness and cardiac remodeling compared with enalapril. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind clinical trial of 464 participants with heart failure and ejection fraction of 40% or less enrolled across 85 US sites between August 17, 2016, and June 28, 2018. Follow-up was completed on January 26, 2019. INTERVENTIONS: Randomization (1:1) to sacubitril-valsartan (n = 231; target dosage, 97/103 mg twice daily) vs enalapril (n = 233; target dosage, 10 mg twice daily) for 12 weeks. MAIN OUTCOMES AND MEASURES: The primary outcome was change from baseline to week 12 in aortic characteristic impedance (Zc), a measure of central aortic stiffness. Prespecified secondary outcomes included change from baseline to week 12 in N-terminal pro-B-type natriuretic peptide, ejection fraction, global longitudinal strain, mitral annular relaxation velocity, mitral E/e' ratio, left ventricular end-systolic and end-diastolic volume indexes (LVESVI and LVEDVI), left atrial volume index, and ventricular-vascular coupling ratio. RESULTS: Of 464 validly randomized participants (mean age, 67.3 [SD, 9.1] years; 23.5% women), 427 completed the study. At 12 weeks, Zc decreased from 223.8 to 218.9 dyne × s/cm5 in the sacubitril-valsartan group and increased from 213.2 to 214.4 dyne × s/cm5 in the enalapril group (treatment difference, -2.2 [95% CI, -17.6 to 13.2] dyne × s/cm5; P = .78). Of 9 prespecified secondary end points, no significant between-group difference in change from baseline was seen in 4, including left ventricular ejection fraction (34%-36% with sacubitril-valsartan vs 33 to 35% with enalapril; treatment difference, 0.6% [95% CI, -0.4% to 1.7%]; P = .24). However, greater reductions from baseline were seen with sacubitril-valsartan than with enalapril in all others, including left atrial volume (from 30.4 mL/m2 to 28.2 mL/m2 vs from 29.8 mL/m2 to 30.5 mL/m2; treatment difference, -2.8 mL/m2 [95% CI, -4.0 to -1.6 mL/m2]; P < .001), LVEDVI (from 75.1 mL/m2 to 70.3 mL/m2 vs from 79.1 mL/m2 to 75.6 mL/m2; treatment difference, -2.0 mL/m2 [95% CI, -3.7 to 0.3 mL/m2]; P = .02), LVESVI (from 50.8 mL/m2 to 46.3 mL/m2 vs from 54.1 to 50.6 mL/m2; treatment difference, -1.6 mL/m2 [95% CI, -3.1 to -0.03 mL/m2]; P = .045), and mitral E/e' ratio (from 13.8 to 12.3 vs from 13.4 to 13.8; treatment difference, -1.8 [95% CI, -2.8 to -0.8]; P = .001). Rates of adverse events including hypotension (1.7% vs 3.9%) were similar in both groups. CONCLUSIONS AND RELEVANCE: Treatment of HFrEF with sacubitril-valsartan, compared with enalapril, did not significantly reduce central aortic stiffness. The study findings may provide insight into mechanisms underlying the effects of sacubitril-valsartan in HFrEF. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02874794.

RESUMEN

Whether aldosterone itself contributes directly to macro- or microcirculatory disease in man or to adverse cardiovascular outcomes is not fully known. We report our long-term single-practice experience in an unusual group of five patients with chronic hyperaldosteronism (HA, including three with glucocorticoid-remediable aldosteronism, GRA) treated with low-dose amiloride (a specific epithelial sodium channel [ENaC] blocker) 5-10 (mean 7) mg daily for 14-28 (mean 20) years. Except for one GRA diagnosed in infancy, all had severe resistant hypertension. In each case, BP was normalized within 1-4 weeks after starting amiloride and office BP's remained well controlled throughout the next two decades. 24-hour ambulatory BP monitoring with pulse wave analysis (cardiac output, vascular resistance, augmentation index, reflection magnitude), regional pulse wave velocities, pulse stiffening ratio, ankle-brachial index, serum creatinine, estimated glomerular filtration rate, and spot urinary albumin:creatinine ratio were measured after a mean of 18 years; all of these indicators were essentially normal. Over two additional years of observation (100 patient-years total), no cardiovascular or renal event occurred. We conclude that long-term ENaC blockade with amiloride can normalize BP and protect macro- and microvascular function in patients with HA. This suggests that either (a) putative vasculopathic effects of aldosterone are mediated via ENaC or (b) aldosterone may not play a direct role in age-dependent vasculopathic changes in humans independent of blood pressure. These findings, coupled with our literature review in both animal and human results, underscore the need for additional studies.

Asunto(s)

Adenoma/tratamiento farmacológico , Amilorida/uso terapéutico , Bloqueadores del Canal de Sodio Epitelial/uso terapéutico , Hiperaldosteronismo/tratamiento farmacológico , Adenoma/fisiopatología , Neoplasias de las Glándulas Suprarrenales/patología , Adulto , Albuminuria/orina , Aldosterona/sangre , Índice Tobillo Braquial/métodos , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Monitoreo Ambulatorio de la Presión Arterial/métodos , Niño , Enfermedad Crónica , Creatinina/sangre , Creatinina/orina , Femenino , Tasa de Filtración Glomerular/fisiología , Humanos , Hiperaldosteronismo/complicaciones , Hipertensión/diagnóstico , Hipertensión/tratamiento farmacológico , Hipertensión/etiología , Hipertensión/patología , Masculino , Microvasos/efectos de los fármacos , Microvasos/fisiopatología , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Análisis de la Onda del Pulso/métodos

RESUMEN

Whether aldosterone itself contributes directly to macro- or microcirculatory disease in man or to adverse cardiovascular outcomes is not fully known. We report our long-term single-practice experience in 5 patients with chronic hyperaldosteronism (HA, including 3 with glucocorticoid remediable aldosteronism, GRA) treated with low-dose amiloride (a specific epithelial sodium channel [ENaC] blocker) 5-10 (mean 7) mg daily for 14-28 (mean 20) years. Except for 1 GRA diagnosed in infancy, all had severe resistant hypertension. In each case, BP was normal or near-normal within 1-4 weeks after starting amiloride and office BP's were well controlled for 20 years thereafter. Vascular studies and 24-hour ambulatory BP monitoring with pulse wave analysis (cardiac output, vascular resistance, augmentation index, and reflection magnitude) were assessed after a mean of 18 years as were regional pulse wave velocities, pulse stiffening ratio, ankle-brachial index, serum creatinine, estimated glomerular filtration rate, and spot urinary albumin:creatinine ratio. All indicators were completely normal in all patients after 18 years of amiloride, and none had a cardiovascular event during the 20-year mean follow-up. We conclude that long-term ENaC blockade can normalize BP and protect macro- and microvascular function in patients with HA. This suggests that (a) any vasculopathic effects of aldosterone are mediated via ENaC, not MR activation itself, and are fully preventable or reversible with ENaC blockade or (b) aldosterone may not play a major BP-independent role in human macro- and microcirculatory diseases. These and other widely divergent results in the literature underscore the need for additional studies regarding aldosterone, ENaC, and vascular disease.

Asunto(s)

Cuidados Posteriores/métodos , Amilorida/administración & dosificación , Monitoreo Ambulatorio de la Presión Arterial/métodos , Hiperaldosteronismo , Hipertensión , Aldosterona/metabolismo , Antihipertensivos/administración & dosificación , Presión Sanguínea/efectos de los fármacos , Diuréticos/administración & dosificación , Resistencia a Medicamentos , Quimioterapia Combinada/métodos , Bloqueadores del Canal de Sodio Epitelial/administración & dosificación , Femenino , Humanos , Hiperaldosteronismo/tratamiento farmacológico , Hiperaldosteronismo/metabolismo , Hiperaldosteronismo/fisiopatología , Hipertensión/tratamiento farmacológico , Hipertensión/etiología , Hipertensión/fisiopatología , Pruebas de Función Renal/métodos , Masculino , Persona de Mediana Edad , Análisis de la Onda del Pulso/métodos , Tiempo

RESUMEN

Pulse wave velocity (PWV), a measure of arterial stiffness, is an independent risk factor for cardiovascular morbidity and mortality. We investigated the relationship of ambulatory brachial cuff-based oscillometric PWV (oPWV) to 2 known correlates: age and brachial systolic blood pressure (SBP). In 234 participants in the Masked Hypertension Study, we analyzed 7284 validated hourly ambulatory SBP and oPWV readings using the Mobil-O-Graph monitor, which uses a proprietary pulse wave analysis algorithm to determine oPWV. Carotid-femoral PWV (cfPWV) was also measured. Mixed linear models were developed to estimate oPWV from age and ambulatory SBP. Participants were 34% male, with mean (SD) age 52.8 (9.9) years, SBP 123.8 (18.4) mm Hg, and oPWV 7.6 (1.3) m/s and cfPWV of 7.7 (1.7) m/s. The relationship of oPWV to age and SBP is given below: [Formula: see text] Age uniquely accounted for an estimated 75% of the total variation of oPWV, whereas SBP uniquely accounted for 20%; these findings were confirmed in an external validation dataset. Together, age and SBP accounted for 99.1% of the total variance of oPWV but (only) 40.2% of the variance of cfPWV. The correlation between oPWV and cfPWV was 0.58 but was only 0.11 after controlling for age and SBP. We conclude that the Mobil-O-Graph's oPWV is nearly completely explained by age and SBP and its relationship to cfPWV is because of their shared associations with age and SBP. Other hemodynamic variables derived from oscillometric pulse wave analysis may be useful and deserve additional scrutiny.

Asunto(s)

Monitoreo Ambulatorio de la Presión Arterial , Enfermedades Cardiovasculares/fisiopatología , Hipertensión Enmascarada/diagnóstico , Hipertensión Enmascarada/mortalidad , Análisis de la Onda del Pulso/métodos , Rigidez Vascular/fisiología , Adulto , Factores de Edad , Anciano , Determinación de la Presión Sanguínea/métodos , Enfermedades Cardiovasculares/prevención & control , Estudios de Cohortes , Bases de Datos Factuales , Femenino , Estudios de Seguimiento , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Análisis de la Onda del Pulso/efectos adversos , Reproducibilidad de los Resultados , Estudios Retrospectivos , Medición de Riesgo , Factores Sexuales , Análisis de Supervivencia , Factores de Tiempo

RESUMEN

The mechanism of the enantioselective Michael addition of diethyl malonate to trans-ß-nitrostyrene catalyzed by a tertiary amine thiourea organocatalyst is explored using experimental 13C kinetic isotope effects and density functional theory calculations. Large primary 13C KIEs on the bond-forming carbon atoms of both reactants suggest that carbon-carbon bond formation is the rate-determining step in the catalytic cycle. This work resolves conflicting mechanistic pictures that have emerged from prior experimental and computational studies.

Asunto(s)

Tiourea/química , Catálisis , Teoría Funcional de la Densidad , Malonatos/química , Estructura Molecular , Estereoisomerismo , Estirenos/síntesis química , Estirenos/química

RESUMEN

BACKGROUND: Empagliflozin, a sodium-glucose cotransporter 2 inhibitor indicated for type 2 diabetes mellitus (T2DM), can lower blood pressure (BP) and reduce cardiovascular mortality in patients with T2DM and preexisting cardiovascular disease. Its effects in blacks have been understudied. METHODS: In this 24-week study, 150 blacks with T2DM and hypertension had glycohemoglobin (primary end point), office and 24-hour ambulatory BP, body weight, and safety assessments. After a 2-week, open-label, placebo run-in, patients were randomly assigned to once daily empagliflozin (10 mg for the first 4 weeks, then force-titrated to 25 mg until week 24) or placebo. A mixed-effects model for repeated measures was performed on the primary and 2 key secondary end points, and an analysis of covariance for nonrepeated measures with last observation carried forward was performed for 2 other key secondary end points. Hierarchical testing was applied for these end points. RESULTS: Overall, 52.7% of participants were men, mean (SD) age, 56.8 (9.3) years; mean duration of T2DM, 9.3 (7.1) years. The baseline values of key parameters (mean [SD]) were as follows: glycohemoglobin, 8.59 (1.02)%; ambulatory systolic BP, 146.3 (11.0) mm Hg; and ambulatory diastolic BP, 89.4 (8.1) mm Hg. By week 24, the mean (standard error) change in glycohemoglobin in the empagliflozin group was -0.77 (0.15%) in comparison with an increase of 0.07 (0.16%) in the placebo group; placebo-corrected difference, -0.78% (95% CI, -1.18 to -0.38; P=0.0002). Reductions in body weight by week 24 were -2.38 (0.38) empagliflozin and -0.80 (0.47) placebo; the placebo-corrected difference was -1.23 kg (95% CI, -2.39 to -0.07; P=0.0382). Empagliflozin significantly reduced 24-hour ambulatory systolic BP versus placebo by weeks 12 and 24 (placebo-corrected difference, -5.21 mm Hg [95% CI, -9.24 to -1.18; P=0.0117] and -8.39 mm Hg [95% CI, -13.74 to -3.04; P=0.0025], respectively). Diastolic BP was also reduced. CONCLUSIONS: In blacks with T2DM, empagliflozin reduced glycohemoglobin, body weight, and BP. The effect of empagliflozin on BP increased from 12 to 24 weeks, suggesting a full antihypertensive effect takes ≥6 months to be fully realized. At week 24, the placebo-subtracted BP effect was similar to standard antihypertensive monotherapies, suggesting that empagliflozin may be beneficial for this high-risk population. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02182830.

Asunto(s)

Compuestos de Bencidrilo/administración & dosificación , Presión Sanguínea/efectos de los fármacos , Complicaciones de la Diabetes/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Glucósidos/administración & dosificación , Hipertensión/tratamiento farmacológico , Anciano , Complicaciones de la Diabetes/sangre , Complicaciones de la Diabetes/fisiopatología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Humanos , Hipertensión/sangre , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad

Asunto(s)

Hipertensión , Presión Sanguínea , Determinación de la Presión Sanguínea , Humanos , Mejoramiento de la Calidad , Factores Socioeconómicos

RESUMEN

OBJECTIVES: Emergency Department crowding is an increasing problem, leading to treatment delays and higher risk of mortality. Our institution recently implemented a telemedicine physician intake ("tele-intake") process as a mitigating front-end strategy. Previous studies have focused on ED throughput metrics such as door to disposition; our work aimed to specifically assess the tele-intake model for clinical accuracy. METHODS: We retrospectively reviewed ED visits at a high acuity, tertiary care academic hospital before and after tele-intake implementation. We defined the primary outcome as the degree of additional laboratory, imaging, and medication orders placed by the subsequent ED provider. Our secondary outcomes were the cancellation rate of intake orders and the percentage of encounters where no additional second provider orders were necessary. RESULTS: For in-person and tele-intake physician encounters between September 2015 and February 2017, most labs and diagnostic radiology studies, and approximately half of CT, ultrasound, and pharmacy orders were initiated by the intake physician. We found no significant difference for our primary outcome (p = 0.2449). For both tele-intake and in-person encounters, <1% of orders were cancelled by the second provider. Additionally, 30.8% of in-person and 31.5% of telemedicine patient encounters required no additional orders to make a disposition decision. DISCUSSION: This novel analysis of an innovative patient care model suggests that the benefits of tele-intake as a replacement for in-person physician directed intake are not at the cost of over or under utilization of diagnostic testing or interventions.

Asunto(s)

Atención a la Salud/métodos , Servicio de Urgencia en Hospital/estadística & datos numéricos , Telemedicina/estadística & datos numéricos , Triaje/estadística & datos numéricos , Técnicas de Laboratorio Clínico/estadística & datos numéricos , Atención a la Salud/estadística & datos numéricos , Diagnóstico por Imagen/estadística & datos numéricos , Quimioterapia/estadística & datos numéricos , Servicio de Urgencia en Hospital/organización & administración , Femenino , Hospitales de Enseñanza , Humanos , Masculino , Estudios Retrospectivos , Telemedicina/normas , Centros de Atención Terciaria , Triaje/organización & administración

RESUMEN

A novel mechanism for the epoxidation of enals with hydrogen peroxide catalyzed by diarylprolinol silyl ether supported by experimental 13C kinetic isotope effects (KIEs) and density functional theory calculations is presented. Normal 13C KIEs, measured on both the carbonyl- and ß-carbon atoms of the enal, suggest participation of both carbon atoms in the rate-determining step. Calculations show that the widely accepted iminium-ion mechanism does not account for this experimental observation. A syn-SN2' substitution mechanism, which avoids formation of a discrete iminium-ion intermediate, emerges as the most likely mechanism based on agreement between experimental and predicted KIEs.

Asunto(s)

Compuestos Epoxi/química , Peróxido de Hidrógeno/química , Iminas/química , Pirrolidinas/química , Catálisis , Éteres/química , Isótopos , Cinética , Modelos Moleculares