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1.
Am Heart J ; 271: 48-54, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38401647

RESUMO

BACKGROUND: Both anticoagulation and antiplatelet therapies are recommended after percutaneous coronary intervention (PCI) in patients with atrial fibrillation (AF). Although contemporary guidelines recommend discontinuation of antiplatelet therapy 1 year after drug-eluting stent (DES) implantation due to excessive bleeding risk, supporting randomized trials are still lacking. METHODS: The ADAPT AF-DES trial is a multicenter, prospective, open-label, randomized, non-inferiority trial, enrolling 960 patients with AF with a CHA2DS2-VASc score > 1, who underwent PCI with DES implantation at least 12 months before enrollment. Eligible patients are randomly assigned to receive either non-vitamin K antagonist oral anticoagulant (NOAC) monotherapy or NOAC plus clopidogrel combination therapy. The primary outcome is net adverse clinical event (NACE) at 1 year after randomization, defined as a composite of all-cause death, myocardial infarction, stent thrombosis, stroke, systemic embolism, and major or clinically relevant non-major bleeding, as defined by the International Society on Thrombosis and Hemostasis criteria. We hypothesize that NOAC monotherapy would be non-inferior to NOAC plus clopidogrel combination therapy for NACE in patients with AF beyond 12 months after DES implantation. CONCLUSIONS: The ADAPT AF-DES trial will evaluate the efficacy and safety of NOAC monotherapy versus NOAC plus clopidogrel combination therapy in patients with AF beyond 12 months after PCI with DES implantation. The ADAPT AF-DES trial will provide robust evidence for an optimal antithrombotic strategy in patients with AF after DES implantation. CLINICAL TRIAL REGISTRATION: https://www. CLINICALTRIALS: gov. Unique identifier: NCT04250116.


Assuntos
Anticoagulantes , Fibrilação Atrial , Clopidogrel , Stents Farmacológicos , Intervenção Coronária Percutânea , Inibidores da Agregação Plaquetária , Feminino , Humanos , Masculino , Anticoagulantes/administração & dosagem , Anticoagulantes/uso terapêutico , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/terapia , Clopidogrel/administração & dosagem , Clopidogrel/uso terapêutico , Quimioterapia Combinada , Hemorragia/induzido quimicamente , Intervenção Coronária Percutânea/métodos , Inibidores da Agregação Plaquetária/uso terapêutico , Inibidores da Agregação Plaquetária/administração & dosagem , Estudos Prospectivos , Acidente Vascular Cerebral/prevenção & controle , Acidente Vascular Cerebral/etiologia , Fatores de Tempo , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Multicêntricos como Assunto
2.
Am Heart J ; 261: 45-50, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36934981

RESUMO

BACKGROUND: Current guidelines recommend that patients with established atherosclerotic cardiovascular disease (ASCVD) use high-intensity statin therapy to lower low-density lipoprotein (LDL)-cholesterol levels by at least 50%, irrespective of age. However, in real-world practice, there is reluctance to maintain statin use in response to side-effects, particularly statin-associated muscle symptoms (SAMS). Moreover, no randomized trial has been conducted on the safety of statin therapy in elderly patients. TRIAL DESIGN: This investigator-initiated, multicenter, randomized clinical trial aimed to investigate the incidence of SAMS and its effect on LDL-cholesterol levels in elderly patients with established ASCVD. Eligible patients were aged 70 years or older with established ASCVD. Consecutive patients who met the inclusion criteria were randomized in a 1:1 fashion to receive either intensive statin monotherapy (rosuvastatin 20 mg) or combination therapy (rosuvastatin/ezetimibe, 5/10 mg). The primary endpoint of the study is SAMS at 6 months with regard to treatment strategy. Positive SAMS results are defined as patients with a proposed statin myalgia index score of 7 or higher. The key secondary end-points are target LDL-cholesterol achievement (LDL < 70 mg/dL), incidence of myopathy, rhabdomyolysis, frequency of drug discontinuation, and creatinine kinase, aspartate transaminase, alanine transaminase, total cholesterol, LDL-cholesterol, high-density lipoprotein-cholesterol, triglyceride, and highly sensitive C-reactive protein levels at 6 months. CONCLUSIONS: The SaveSAMS study is a multicenter, randomized trial that will compare the incidence of SAMS in patients with established ASCVD who are 70 years or older on intensive statin monotherapy to that combination therapy.


Assuntos
Anticolesterolemiantes , Aterosclerose , Doenças Cardiovasculares , Inibidores de Hidroximetilglutaril-CoA Redutases , Idoso , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Rosuvastatina Cálcica/efeitos adversos , Ezetimiba/efeitos adversos , Anticolesterolemiantes/uso terapêutico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Doenças Cardiovasculares/induzido quimicamente , Aterosclerose/tratamento farmacológico , LDL-Colesterol , Quimioterapia Combinada , Resultado do Tratamento
3.
Medicina (Kaunas) ; 59(9)2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37763768

RESUMO

Background and Objectives: Polymer-free ultrathin strut sirolimus- and probucol-eluting stents (PF-SES) are recognized as safe and effective in diverse patient populations, although the implications of post-dilation during stent implantation remain underexamined. Materials and Methods: In this study, patients implanted with PF-SES at Gachon University Gil Medical Center between December 2014 and February 2018 were evaluated. Major adverse cardiovascular events (MACE), encompassing nonfatal myocardial infarction (MI), nonfatal stroke, and cardiovascular death were identified as primary outcomes, with secondary outcomes including target vessel revascularization (TVR), target lesion revascularization (TLR), and in-stent restenosis (ISR). Results: Of the 384 initial patients, 299 were considered eligible for analysis. The groups, delineated by those undergoing post-dilation (143 patients) and those not (156 patients), exhibited comparable rates of primary outcomes [hazard ratio (HR), 2.17; 95% confidence interval (CI), 0.40 to 11.87; p = 0.37]. The outcomes remained consistent irrespective of the post-dilation status and were similarly unaffected in multivariate analyses (HR, 2.90; 95% CI, 0.52 to 16.34; p = 0.227). Conclusions: These results suggest that the clinical outcomes of patients with post-dilation were similar to that of those without post-dilation in those with the polymer-free sirolimus- and probucol-eluting stents.

4.
Rev Cardiovasc Med ; 23(1): 18, 2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35092210

RESUMO

BACKGROUND: For the Asian patients with STEMI undergoing PCI, ACEIs are known to have a better outcome than ARBs. However, there is limited evidence to suggest so. METHODS: Among the STEMI registry consist of 1142 Korean patients, we compared the MACE, the composite of myocardial infarction, stoke, death, admission for heart failure, and target vessel revascularization, between the ACEI and ARB groups (Set 1). Further, we defined adequate medication as the administration of a dose equal to or higher than the initiation dose of ACEI according to the heart failure guideline recommendation with a mandatory addition of beta-blockers, and compared the outcomes between the inadequate and adequate medication groups (Set 2). Propensity score matching was used to eliminate difference. RESULTS: In the Set 1 comparison, patients in the ACEI group had a better outcome than those in the ARB group for both whole and matched populations (whole and matched population: Cox regression hazard ratio [HR], 0.645 and 0.535; 95% confidence interval [CI], 0.440-0.944 and 0.296-0.967; p = 0.024 and p = 0.039, respectively). In the Set 2 comparison for the whole population, patients in the inadequate medication group had more MACE than those in the adequate medication group (HR, 0.673; 95% CI, 0.459-0.985; p = 0.042). However, no difference was observed after propensity score matching (HR, 1.023; 95% CI, 0.654-1.602; p = 0.919). CONCLUSION: ACEIs might be a better choice than ARBs after primary revascularization. However, this study's findings suggest that early ACEI dose escalation combined with beta-blocker use may not improve prognosis.


Assuntos
Intervenção Coronária Percutânea , Infarto do Miocárdio com Supradesnível do Segmento ST , Antagonistas de Receptores de Angiotensina/efeitos adversos , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Angiotensinas/uso terapêutico , Humanos , Revascularização Miocárdica , Renina/uso terapêutico , Estudos Retrospectivos , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico por imagem , Infarto do Miocárdio com Supradesnível do Segmento ST/terapia , Resultado do Tratamento
5.
Circ J ; 86(9): 1365-1375, 2022 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-35896356

RESUMO

BACKGROUND: Differences in the impact of the 1- or 2-stent strategy in similar coronary bifurcation lesion conditions are not well understood. This study investigated the clinical outcomes and its predictors between 1 or 2 stents in propensity score-matched (PSM) complex bifurcation lesions.Methods and Results: We analyzed the data of patients with bifurcation lesions, obtained from a multicenter registry of 2,648 patients (median follow up, 53 months). The patients were treated by second generation drug-eluting stents (DESs). The primary outcome was target lesion failure (TLF), composite of cardiac death, target vessel myocardial infarction (TVMI), and ischemia-driven target lesion revascularization (TLR). PSM was performed to balance baseline clinical and angiographic discrepancies between 1 and 2 stents. After PSM (N=333 from each group), the 2-stent group had more TLRs (hazard ratio [HR] 3.14, 95% confidence interval [CI] 1.42-6.97, P=0.005) and fewer hard endpoints (composite of cardiac death and TVMI; HR 0.44, 95% CI 0.19-1.01, P=0.054), which resulted in a similar TLF rate (HR 1.40, 95% CI 0.83-2.37, P=0.209) compared to the 1-stent group. Compared with 1-stent, the 2-stent technique was more frequently associated with less TLF in the presence of main vessel (pinteraction=0.008) and side branch calcification (pinteraction=0.010). CONCLUSIONS: The 2-stent strategy should be considered to reduce hard clinical endpoints in complex bifurcation lesions, particularly those with calcifications.


Assuntos
Doença da Artéria Coronariana , Infarto do Miocárdio , Intervenção Coronária Percutânea , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/cirurgia , Morte , Humanos , Infarto do Miocárdio/etiologia , Intervenção Coronária Percutânea/efeitos adversos , Sistema de Registros , Estudos Retrospectivos , Stents , Resultado do Tratamento
6.
Sensors (Basel) ; 22(6)2022 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-35336397

RESUMO

A new development process for the noise, vibration, and harshness (NVH) of a vehicle is presented using data analysis and machine learning with long-term NVH driving data. The process includes exploratory data analysis (EDA), variable importance analysis, correlation analysis, sensitivity analysis, and development target selection. In this paper, to dramatically reduce the development period and cost related to vehicle NVH, we propose a technique that can accurately identify the precise connectivity and relationship between vehicle systems and NVH factors. This new technique uses whole big data and reflects the nonlinearity of dynamic characteristics, which was not considered in existing methods, and no data are discarded. Through the proposed method, it is possible to quickly find areas that need improvement through correlation analysis and variable importance analysis, understand how much room noise increases when the NVH level of the system changes through sensitivity analysis, and reduce vehicle development time by improving efficiency. The method could be used in the development process and the validation of other deep learning and machine learning models. It could be an essential step in applying artificial intelligence, big data, and data analysis in the vehicle and mobility industry as a future vehicle development process.

7.
Inorg Chem ; 60(22): 17348-17356, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34709799

RESUMO

The replacement of phosphine substituents in nickel-bound PNNP ligands is reported as an alternative method for preparing multidentate phosphine ligands with alkyl substituents. Treatment of the previously reported bis(phosphide) complex {K(THF)x}22Ph[PNNP]Ni (2) with 2 equiv of MeI, iPrI, and 1,3-dibromoethane formed alkyl-substituted complexes 2Ph,2Me[PNNP]Ni (3), 2Ph,2iPr[PNNP]Ni (4), and 2Ph,propylene[PNNP]Ni (5), respectively. The stereoselectivity (racemic vs meso) of these reactions can be controlled by varying the reaction temperature. The racemic mixtures of products with the new alkyl substituents in an anti configuration were favored at lower temperatures, whereas a larger proportion of meso compounds was acquired at higher temperatures. Further treatment of 3 with KH resulted in selective elimination of the remaining phenyl groups rather than the methyl substituents, affording bis(methylphosphide) complex {K(THF)x}22Me[PNNP]Ni (6). Subsequent treatment of 6 with additional MeI formed 4Me[PNNP]Ni (7), in which all four phenyl groups were replaced with methyl substituents. As a proof of concept, demetalation of the ligand from 7 was achieved using aqueous KCN to form a free dimethylphosphine-substituted ligand H24Me[PNNP] (8), and 8 was subsequently coordinated to a different metal, using PdCl2 to form 4Me[PNNP]Pd (9). Unlike the clean elimination of phenyl substituents from 3, the reactions of KH with 4 and 5 exhibited competitive elimination of both alkyl and phenyl substituents and/or attenuated reactivity.

8.
Mar Drugs ; 19(8)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34436274

RESUMO

Ultraviolet (UV) B exposure is a prominent cause of skin aging and a contemporary subject of interest. The effects are progressing through the generation of reactive oxygen species (ROS) that alter cell signaling pathways related to inflammatory responses. The present study evaluates the protective effects of (7aR)-6-hydroxy-4,4,7a-trimethyl-6,7-dihydro-5H-1-benzofuran-2-one (HTT) isolated from the edible brown algae Sargassum horneri against UVB protective effects in human dermal fibroblasts (HDFs). HTT treatment dose-dependently suppressed intracellular ROS generation in HDFs with an IC50 of 62.43 ± 3.22 µM. HTT abated UVB-induced mitochondrial hyperpolarization and apoptotic body formation. Furthermore, UVB-induced activation of key nuclear factor (NF)-κB and mitogen-activated protein kinase signaling proteins were suppressed in HTT treated cells while downregulating pro-inflammatory cytokines (interleukin-1ß, 6, 8, 33 and tumor necrosis factor-α). Moreover, HTT treatment downregulated matrix metalloproteinase1, 2, 3, 8, 9 and 13 that was further confirmed by the inhibition of collagenase and elastase activity. The evidence implies that HTT delivers protective effects against premature skin aging caused by UVB exposure via suppressing inflammatory responses and degradation of extracellular matrix (ECM) components. Extensive research in this regard will raise perspectives for using HTT as an ingredient in UV protective ointments.


Assuntos
Benzofuranos/farmacologia , Fibroblastos/efeitos dos fármacos , Sargassum , Envelhecimento da Pele , Organismos Aquáticos , Humanos , Concentração Inibidora 50 , Estresse Oxidativo/efeitos dos fármacos , Fitoterapia , Pele/efeitos dos fármacos , Raios Ultravioleta
9.
BMC Cardiovasc Disord ; 20(1): 486, 2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33208092

RESUMO

BACKGROUND: Several biomarkers have been proposed as independent predictors of poor outcomes in ST-segment elevation myocardial infarction (STEMI). We investigated whether adding information obtained from routine blood tests including hypoxic liver injury (HLI), dysglycemia, anemia, and high neutrophil to lymphocyte ratio (NLR) could improve the prognostic performance of the TIMI risk score for the prediction of 1-year mortality. METHODS: A total of 1057 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) between 2007 and 2014 were retrospectively enrolled from 4-regional hospitals. HLI and dysglycemia were defined as serum transaminase > twice the normal upper limit and glucose < 90 or > 250 mg/dL, respectively. The effect of adding biomarkers to the TIMI risk score on its discriminative ability was assessed using c-statistic, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). RESULTS: The 1-year mortality rate was 7.1%. The best cutoff value of NLR for the prediction of 1-year mortality was 4.3 (sensitivity, 67%; specificity, 65%). HLI (HR 2.019; 95% CI 1.104-3.695), dysglycemia (HR 2.535; 95% CI 1.324-3.923), anemia (HR 2.071; 95% CI 1.093-3.923), and high NLR (HR 3.651; 95% CI 1.927-6.918) were independent predictors of 1-year mortality. When these 4 parameters were added to the TIMI risk score, the c-statistic significantly improved from 0.841 to 0.876 (p < 0.001), and the NRI and IDI were estimated at 0.203 (95% CI 0.130-0.275; p < 0.001) and 0.089 (95% CI 0.060-0.119; p < 0.001), respectively. CONCLUSIONS: The addition of HLI, dysglycemia, anemia, and high NLR to the TIMI risk score may be useful for very early risk stratification in patients with STEMI receiving primary PCI.


Assuntos
Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Análise Química do Sangue , Glicemia/metabolismo , Hemoglobinas/metabolismo , Linfócitos , Neutrófilos , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Feminino , Humanos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Admissão do Paciente , Intervenção Coronária Percutânea/mortalidade , Valor Preditivo dos Testes , Sistema de Registros , República da Coreia , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Infarto do Miocárdio com Supradesnível do Segmento ST/sangue , Infarto do Miocárdio com Supradesnível do Segmento ST/mortalidade , Infarto do Miocárdio com Supradesnível do Segmento ST/terapia , Fatores de Tempo , Resultado do Tratamento
10.
Perfusion ; 35(4): 338-347, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31608761

RESUMO

BACKGROUND: The selection of ß-blocker for survivors after primary intervention due to acute ST-elevation myocardial infarction seems crucial to improve the outcomes. However, rare comparison data existed for these patients. We aimed to compare the effectiveness of selective ß-blockers to that of carvedilol in patients treated with primary intervention. METHODS AND RESULTS: Among the 1,485 patients in the "INTERSTELLAR" registry between 2007 and 2015, 238 patients with selective ß-blockers (bisoprolol, nebivolol, atenolol, bevantolol, and betaxolol) and 988 with carvedilol were included and their clinical outcomes were compared for a 2-year observation period. In the clinical baseline characteristics, the unfavorable trends in the carvedilol group were high Killip presentation, lower ejection fractions, smaller diameters, and longer lengths of deployed stents. Although mortality (2.5% vs. 1.7%; p = 0.414) and the rate of stroke (0.8% vs. 0.6%; p = 0.693) were not different between groups, the rate of recurrent myocardial infarction (4.6% vs. 1.2%; p = 0.001) and of target vessel revascularization (4.2% vs. 0.9%; p < 0.001) were lower in the carvedilol group. After eliminating the difference by propensity matching, the similar outcome result was shown (all-cause death, 0.6% vs. 1.0%, p = 0.678; stroke, 0.6% vs. 1.2%, p = 0.479; myocardial infarction, 5.0% vs. 1.2%, p = 0.003; target vessel revascularization, 4.5% vs. 0.7%, p < 0.006) for 595 matched populations. The use of carvedilol was also determined to be an independent predictor for recurrent myocardial infarctions (hazard ratio = 0.305; p = 0.005; 95% confidence interval = 0.13-0.69). CONCLUSION: Use of a carvedilol in ST-segment myocardial infarction survivor is associated with lower recurrent myocardial infarction events. Thus, it might be the better choice of ß-blocker for secondary prevention in ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention.


Assuntos
Antagonistas Adrenérgicos beta/uso terapêutico , Infarto do Miocárdio com Supradesnível do Segmento ST/tratamento farmacológico , Antagonistas Adrenérgicos beta/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
11.
Ther Drug Monit ; 41(1): 102-106, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30299430

RESUMO

BACKGROUND: Colistin is increasingly used as the last therapeutic option for the treatment of multidrug-resistant, Gram-negative bacterial infections. To ensure safe and efficacious use of colistin, therapeutic drug monitoring (TDM) is needed due to its narrow therapeutic window. This study aimed to evaluate the pharmacokinetic (PK) characteristics of colistin and to guide TDM in colistin-treated patients in Korea. METHODS: In a prospective study, we analyzed PK characteristics in 15 patients who intravenously received colistin methanesulfonate twice per day. Colistin methanesulfonate doses were adjusted based on renal function of the subjects. The appropriate blood sampling points for TDM were evaluated by analyzing the correlations between the PK parameters and the plasma concentrations at each time point. RESULTS: The mean values for the minimum, maximum, and average concentrations (Cmin, Cmax, and Caverage) of colistin at steady state were 2.29, 5.5, and 3.38 mg/L, respectively. The dose-normalized Cmin, Cmax, Caverage, and area under the plasma concentration-time curve from 0 to the last measurable concentration (AUClast) showed negative correlations with the creatinine clearance. The combination of the 0- and 2-hour post-dose plasma concentrations was evaluated as the appropriate sampling point for TDM. Two patients reported nephrotoxic adverse events during colistin administration. CONCLUSIONS: Our study clarifies the PK characteristics of successful colistin treatment using TDM. Further evaluations in a larger patient population are needed to confirm the clinical usefulness of colistin TDM.


Assuntos
Antibacterianos/farmacocinética , Antibacterianos/uso terapêutico , Colistina/farmacocinética , Colistina/uso terapêutico , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Monitoramento de Medicamentos/métodos , Feminino , Humanos , Infusões Intravenosas/métodos , Masculino , Testes de Sensibilidade Microbiana/métodos , Pessoa de Meia-Idade , Estudos Prospectivos , República da Coreia
12.
Inorg Chem ; 58(19): 12756-12774, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31490065

RESUMO

The continued development of redox-active ligands requires an understanding as to how ligand modifications and related factors affect the locus of redox activity and spin density in metal complexes. Here we describe the synthesis, characterization, and electronic structure of nickel complexes containing triaryl NNNN (1) and SNNS (2) ligands derived from o-phenylenediamine. The tetradentate ligands in 1 and 2 were investigated and compared to those in metal complexes with compositionally similar ligands to determine how ligand-centered redox properties change when redox-active flanking groups are replaced with redox-innocent NMe2 or SMe. A derivative of 2 in which the phenylene backbone was replaced with ethylene (3) was also prepared to interrogate the importance of o-phenylenediamine for ligand-centered redox activity. Cyclic voltammograms collected for 1 and 2 revealed two fully reversible ligand-centered redox events. Remarkably, several quasi-reversible ligand-centered redox waves were also observed for 3 despite the absence of the o-phenylenediamine subunit. Oxidizing 1 and 2 with silver salts containing different counteranions (BF4-, OTf-, NTf2-) allowed the electrochemically generated complexes to be analyzed as a function of different oxidation states using single-crystal X-ray diffraction (XRD), EPR spectroscopy, and S K-edge X-ray absorption spectroscopy. The experimental data are corroborated by DFT calculations, and together, they reveal how the location of unpaired spin density and electronic structure in singly and doubly oxidized salts of 1 and 2 varies depending on the coordinating ability of the counteranions and exogenous ligands such as pyridine.

13.
Angew Chem Int Ed Engl ; 58(36): 12451-12455, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31271502

RESUMO

Bond distance is a common structural metric used to assess changes in metal-ligand bonds, but it is not clear how sensitive changes in bond distances are with respect to changes in metal-ligand covalency. Here we report ligand K-edge XAS studies on Ni and Pd complexes containing different phosphorus(III) ligands. Despite the large number of electronic and structural permutations, P K-edge pre-edge peak intensities reveal a remarkable correlation that spectroscopically quantifies the linear interdependence of covalent M-P σ bonding and bond distance. Cl K-edge studies conducted on many of the same Ni and Pd compounds revealed a poor correlation between M-Cl bond distance and covalency, but a strong correlation was established by analyzing Cl K-edge data for Ti complexes with a wider range of Ti-Cl bond distances. Together these results establish a quantitative framework to begin making more accurate assessments of metal-ligand covalency using bond distances from readily-available crystallographic data.

14.
Angew Chem Int Ed Engl ; 58(21): 6993-6998, 2019 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-30901511

RESUMO

Constraining σ3 -P compounds in nontrigonal, entatic geometries has proven to be an effective strategy for promoting biphilic oxidative addition reactions more typical of transition metals. Although qualitative descriptions of the impact of structure and symmetry on σ3 -P complexes have been proposed, electronic structure variations responsible for biphilic reactivity have yet to be elucidated experimentally. Reported here are P K-edge XANES data and complementary TDDFT calculations for a series of structurally modified P(N)3 complexes that both validate and quantify electronic structure variations proposed to give rise to biphilic reactions at phosphorus. These data are presented alongside experimentally referenced electronic structure calculations that reveal nontrigonal structures predicted to further enhance biphilic reactivity in σ3 -P ligands and catalysts.


Assuntos
Compostos Organofosforados/química , Fósforo/química , Elementos de Transição/química , Catálise , Ligantes , Modelos Moleculares , Oxirredução , Espectroscopia por Absorção de Raios X
15.
J Synchrotron Radiat ; 25(Pt 2): 529-536, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29488933

RESUMO

P K-edge X-ray absorption near-edge structure (XANES) spectroscopy is a powerful method for analyzing the electronic structure of organic and inorganic phosphorus compounds. Like all XANES experiments, P K-edge XANES requires well defined and readily accessible calibration standards for energy referencing so that spectra collected at different beamlines or under different conditions can be compared. This is especially true for ligand K-edge X-ray absorption spectroscopy, which has well established energy calibration standards for Cl (Cs2CuCl4) and S (Na2S2O3·5H2O), but not neighboring P. This paper presents a review of common P K-edge XANES energy calibration standards and analysis of PPh4Br as a potential alternative. The P K-edge XANES region of commercially available PPh4Br revealed a single, highly resolved pre-edge feature with a maximum at 2146.96 eV. PPh4Br also showed no evidence of photodecomposition when repeatedly scanned over the course of several days. In contrast, we found that PPh3 rapidly decomposes under identical conditions. Density functional theory calculations performed on PPh3 and PPh4+ revealed large differences in the molecular orbital energies that were ascribed to differences in the phosphorus oxidation state (III versus V) and molecular charge (neutral versus +1). Time-dependent density functional theory calculations corroborated the experimental data and allowed the spectral features to be assigned. The first pre-edge feature in the P K-edge XANES spectrum of PPh4Br was assigned to P 1s → P-C π* transitions, whereas those at higher energy were P 1s → P-C σ*. Overall, the analysis suggests that PPh4Br is an excellent alternative to other solid energy calibration standards commonly used in P K-edge XANES experiments.

16.
Inorg Chem ; 57(21): 13188-13200, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-30351072

RESUMO

Borenium ions (i.e., three-coordinate boron cations) are known to promote a wide variety of stoichiometric and catalytic reactions because of their high Lewis acidity. As demonstrated by the growing number of chemically reactive borane ligands, there is considerable interest in developing ligands with highly electrophilic boron sites that promote multisite reactivity in metal complexes. However, there are currently few examples of ligand-centered borenium ions, especially with ligands that form coordination complexes with a wide range of metals. Here we report borenium-like reactivity on a highly versatile diphosphine ligand. Treating (PhTBDPhos)NiCl2 (1) with strong Bronsted acids such as HBF4·Et2O, HOTf, or HNTf2 resulted in fluoride or chloride abstraction from BF4- or NiCl2, respectively, to form trans N-H and B-X bonds on the ligand backbone. HCl addition to the bridgehead N-B bond is reversible, and the reactivity depends on the identity of the supporting counteranions, as observed when treating [(PhTBDPhos)NiCl]2X2, where X = NTf2- (3), OTf- (4), or BArF4- (5), with HCl. The reaction of 4 with HNTf2 instead of HCl yielded NMR evidence of the latent borenium cation in solution and showed how poor nucleophiles such as triflate bind to the borenium ion in the solid state. Remarkably, replacing the chloride ligands in 1 with chelating and less-labile thiolates or catecholates, or changing the phosphorus substituents (phenyl to isopropyl), attenuates the reactivity on the ligand backbone. Density functional theory was used to quantify the reaction free energies, and the theoretical results corroborate the experimental observations. Given the broad utility of diphosphines in homogeneous catalysis and the known benefits of strong Lewis acid promotors in many catalytic reactions, we anticipate that the results will provide new opportunities for dual-site reactivity involving boron ligands and metals.

17.
Inorg Chem ; 57(16): 10277-10286, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-30067355

RESUMO

Diphosphines are highly versatile ancillary ligands in coordination chemistry and catalysis because their structures and donor-acceptor properties can vary widely depending on the substituents attached to phosphorus. Experimental and theoretical methods have been developed to quantify differences in phosphine and diphosphine ligand field strength, but experimentally measuring individual σ-donor and π-acceptor contributions to metal-phosphorus bonding remains a formidable challenge. Here we report P and Cl K-edge X-ray absorption spectroscopy (XAS), density functional theory (DFT), and time-dependent density functional theory (TDDFT) studies of a series of [Ph2P(CH2) nPPh2]TiCl4 complexes, where n = 1, 2, or 3. The d0 metal complexes (Ti4+) revealed both P 1s → Ti-P π and P 1s → Ti-P σ* transitions in the P K-edge XAS spectra, which allowed spectral changes associated with Ti-P σ-bonding and π-backbonding to be evaluated as a function of diphosphine alkane length. DFT and TDDFT calculations were used to assign and quantify changes in Ti-P σ-bonding and π-backbonding. The calculated results for [Ph2P(CH2)2PPh2]TiCl4 were subsequently compared to electronic structure calculations and simulated spectra for [R2P(CH2)2PR2]TiCl4, where R = cyclohexyl or CF3, to evaluate spectral changes as a function of diphosphine ligand field strength. Collectively, our results demonstrate how P K-edge XAS can be used to experimentally measure M-P π-backbonding with a d0 metal and corroborate earlier studies showing that relative changes in covalent M-P σ bonding do not depend solely on changes in diphosphine bite angle.

18.
Circ J ; 82(6): 1632-1639, 2018 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-29593145

RESUMO

BACKGROUND: Indwelling urethral catheters (IUC) are routinely inserted for the purpose of monitoring urine output in patients with acute heart failure (AHF). The benefit of IUC in patients capable of complying with urine collection protocols is unclear, and IUC carry multiple risks. This study describes the impact of IUC on AHF treatment.Methods and Results:A total of 540 records were retrospectively analyzed. After exclusion criteria were applied, 316 patients were propensity matched to establish groups of 100 AHF patients who either did (IUC(+)) or did not receive an IUC (IUC(-)) upon admission. Hospital length of stay (9 vs. 7 days), in-hospital urinary complications (24 vs. 5%), and 1-year urinary tract infection rate (17 vs. 6%; HR, 3.145; 95% CI: 1.240-7.978) were significantly higher in the IUC(+) group (P<0.05 for all). There were no differences in 30-day rehospitalization (6 vs. 6%; HR, 0.981; 95% CI: 0.318-3.058; P=0.986) or major adverse cardiac/cerebrovascular events at 1 year (37 vs. 32%, HR, 1.070; 95% CI: 0.636-1.799; P=0.798). CONCLUSIONS: Based on this retrospective analysis, the routine use of IUC may increase length of stay and UTI complications in AHF patients without reducing the risk for major cardiovascular and cerebrovascular events or 30-day rehospitalization rate.


Assuntos
Insuficiência Cardíaca/terapia , Cateterismo Urinário/efeitos adversos , Infecções Urinárias/etiologia , Doença Aguda , Idoso , Idoso de 80 Anos ou mais , Cateteres de Demora/efeitos adversos , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento
19.
Korean J Physiol Pharmacol ; 20(6): 657-667, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27847443

RESUMO

Critical limb ischemia (CLI) is one of the most severe forms of peripheral artery diseases, but current treatment strategies do not guarantee complete recovery of vascular blood flow or reduce the risk of mortality. Recently, human bone marrow derived mesenchymal stem cells (MSCs) have been reported to have a paracrine influence on angiogenesis in several ischemic diseases. However, little evidence is available regarding optimal cell doses and injection frequencies. Thus, the authors undertook this study to investigate the effects of cell dose and injection frequency on cell survival and paracrine effects. MSCs were injected at 106 or 105 per injection (high and low doses) either once (single injection) or once in two consecutive weeks (double injection) into ischemic legs. Mice were sacrificed 4 weeks after first injection. Angiogenic effects were confirmed in vitro and in vivo, and M2 macrophage infiltration into ischemic tissues and rates of limb salvage were documented. MSCs were found to induce angiogenesis through a paracrine effect in vitro, and were found to survive in ischemic muscle for up to 4 weeks dependent on cell dose and injection frequency. In addition, double high dose and low dose of MSC injections increased vessel formation, and decreased fibrosis volumes and apoptotic cell numbers, whereas a single high dose did not. Our results showed MSCs protect against ischemic injury in a paracrine manner, and suggest that increasing injection frequency is more important than MSC dosage for the treatment CLI.

20.
J Comput Assist Tomogr ; 39(1): 125-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25229204

RESUMO

We report on an extremely rare case of a fake lesion in the left ventricle on electrocardiogram-gated cardiac computed tomography simulating thrombus or tumor by turbulent flow in a 14-year-old boy. Cardiac magnetic resonance imaging with contrast-enhanced myocardial perfusion and delayed enhancement images were helpful in excluding true thrombus or tumor. Awareness of this potential pitfall is critical in order to avoid unnecessary anticoagulation or surgery.


Assuntos
Artefatos , Técnicas de Imagem de Sincronização Cardíaca/métodos , Neoplasias Cardíacas/diagnóstico por imagem , Trombose/diagnóstico por imagem , Disfunção Ventricular Esquerda/diagnóstico por imagem , Adolescente , Velocidade do Fluxo Sanguíneo , Diagnóstico Diferencial , Reações Falso-Positivas , Neoplasias Cardíacas/fisiopatologia , Humanos , Masculino , Radiografia , Trombose/fisiopatologia , Disfunção Ventricular Esquerda/fisiopatologia
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