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1.
Crit Care Med ; 51(8): 1023-1032, 2023 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-36971440

RESUMEN

OBJECTIVES: Studies have suggested intrapulmonary shunts may contribute to hypoxemia in COVID-19 acute respiratory distress syndrome (ARDS) with worse associated outcomes. We evaluated the presence of right-to-left (R-L) shunts in COVID-19 and non-COVID ARDS patients using a comprehensive hypoxemia workup for shunt etiology and associations with mortality. DESIGN: Prospective, observational cohort study. SETTING: Four tertiary hospitals in Edmonton, Alberta, Canada. PATIENTS: Adult critically ill, mechanically ventilated, ICU patients admitted with COVID-19 or non-COVID (November 16, 2020, to September 1, 2021). INTERVENTIONS: Agitated-saline bubble studies with transthoracic echocardiography/transcranial Doppler ± transesophageal echocardiography assessed for R-L shunts presence. MEASUREMENTS AND MAIN RESULTS: Primary outcomes were shunt frequency and association with hospital mortality. Logistic regression analysis was used for adjustment. The study enrolled 226 patients (182 COVID-19 vs 42 non-COVID). Median age was 58 years (interquartile range [IQR], 47-67 yr) and Acute Physiology and Chronic Health Evaluation II scores of 30 (IQR, 21-36). In COVID-19 patients, the frequency of R-L shunt was 31 of 182 COVID patients (17.0%) versus 10 of 44 non-COVID patients (22.7%), with no difference detected in shunt rates (risk difference [RD], -5.7%; 95% CI, -18.4 to 7.0; p = 0.38). In the COVID-19 group, hospital mortality was higher for those with R-L shunt compared with those without (54.8% vs 35.8%; RD, 19.0%; 95% CI, 0.1-37.9; p = 0.05). This did not persist at 90-day mortality nor after adjustment with regression. CONCLUSIONS: There was no evidence of increased R-L shunt rates in COVID-19 compared with non-COVID controls. R-L shunt was associated with increased in-hospital mortality for COVID-19 patients, but this did not persist at 90-day mortality or after adjusting using logistic regression.


Asunto(s)
COVID-19 , Síndrome de Dificultad Respiratoria , Humanos , Adulto , Persona de Mediana Edad , Estudios Prospectivos , Ecocardiografía , Hipoxia , Unidades de Cuidados Intensivos , Alberta
2.
Mar Drugs ; 21(7)2023 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-37504921

RESUMEN

Recombinant peptide synthesis allows for large-scale production of peptides with therapeutic potential. However, access to dicarba peptidomimetics via sidechain-deprotected sequences becomes challenging with exposed Lewis basicity presented by amine and sulfur-containing residues. Presented here is a combination of strategies which can be used to deactivate coordinative residues and achieve high-yielding Ru-catalyzed ring-closing metathesis. The chemistry is exemplified using α-conotoxin EpI, a native bicyclic disulfide-containing sequence isolated from the marine conesnail Conus episcopatus. Replacement of the loop I disulfide with E/Z-dicarba bridges was achieved with high conversion via solution-phase ring-closing metathesis of the unprotected linear peptide after simple chemoselective oxidation and ion-exchange masking of problematic functionality. Metathesis was also attempted in green solvent choices to further improve the sustainability of dicarba peptide synthesis.


Asunto(s)
Conotoxinas , Cistina , Péptidos/química , Disulfuros/química , Oxidación-Reducción , Conotoxinas/química
3.
Mar Drugs ; 21(2)2023 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-36827123

RESUMEN

Elevenins are peptides found in a range of organisms, including arthropods, annelids, nematodes, and molluscs. They consist of 17 to 19 amino acid residues with a single conserved disulfide bond. The subject of this study, elevenin-Vc1, was first identified in the venom of the cone snail Conus victoriae (Gen. Comp. Endocrinol. 2017, 244, 11-18). Although numerous elevenin sequences have been reported, their physiological function is unclear, and no structural information is available. Upon intracranial injection in mice, elevenin-Vc1 induced hyperactivity at doses of 5 or 10 nmol. The structure of elevenin-Vc1, determined using nuclear magnetic resonance spectroscopy, consists of a short helix and a bend region stabilised by the single disulfide bond. The elevenin-Vc1 structural fold is similar to that of α-conotoxins such as α-RgIA and α-ImI, which are also found in the venoms of cone snails and are antagonists at specific subtypes of nicotinic acetylcholine receptors (nAChRs). In an attempt to mimic the functional motif, Asp-Pro-Arg, of α-RgIA and α-ImI, we synthesised an analogue, designated elevenin-Vc1-DPR. However, neither elevenin-Vc1 nor the analogue was active at six different human nAChR subtypes (α1ß1εδ, α3ß2, α3ß4, α4ß2, α7, and α9α10) at 1 µM concentrations.


Asunto(s)
Conotoxinas , Caracol Conus , Receptores Nicotínicos , Ratones , Humanos , Animales , Conotoxinas/farmacología , Caracol Conus/metabolismo , Ponzoñas , Receptores Nicotínicos/metabolismo , Péptidos/metabolismo , Antagonistas Nicotínicos/farmacología
4.
J Adv Nurs ; 78(4): 1140-1153, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35128720

RESUMEN

AIM: To analyse the nature and extent of sponsorship of nursing professional associations and their major scientific conferences. DESIGN: Cross-sectional content analysis. METHODS: Data were extracted from the websites and conference documents of 156 national and international professional nursing associations in 2019 to identify sponsors. Sponsorship prospectuses were analysed to estimate the value and describe the nature of sponsorship arrangements. We analysed sponsorship patterns using social network analysis. RESULTS: Most associations (84/156, 54%) did not report any sponsors. Sponsorship was concentrated among specialty nursing associations in high-income countries. Half of identified sponsors promoted products used in clinical care (50%; 981/1969); the majority represented the medical device industry (69%; 681/981). Top sponsors generally favoured opportunities that promoted interaction with conference attendees. CONCLUSION: Globally, commercial sponsorship of nursing associations is a common, but not the dominant source of support for these activities. Half of sponsors were commercial entities that manufactured or distributed products used during clinical care, which presents a risk of commercial influence over education and ultimately, clinical practice. Sponsors favoured opportunities to interact directly with nurses, determine educational content, or foster continued interaction.


Asunto(s)
Estudios Transversales , Humanos
5.
J Hand Ther ; 35(2): 186-199, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35227556

RESUMEN

BACKGROUND: Scar massage is a widely used treatment modality in hand therapy. This intervention is thoroughly discussed in the literature relating to burns rehabilitation, however, the evidence for its use in treating linear scars following surgery is limited. PURPOSE OF STUDY: To collate the empirical literature on scar massage for the treatment of postsurgical cutaneous scars. STUDY DESIGN: Scoping review. METHODS: Medline, EMBASE, CINAHL, AMED, Scopus, ProQuest Dissertations & Theses Global, and the Joanna Briggs Institute were searched from inception to December 2020. Two researchers used a data extraction tool to record key demographic, intervention and outcome data, and to apply the Oxford Levels of Evidence for each study. RESULTS: Twenty-five studies met the inclusion criteria, reporting on a combined sample of 1515 participants. Only two papers addressed hand or wrist scars (92 participants). While all studies reported favorable outcomes for scar massage, there were 45 different outcome measures used and a propensity towards non-standardized assessment. Intervention protocols varied from a single session to three treatments daily for 6 months. The results from 13 studies were confounded by the implementation of additional rehabilitation interventions. CONCLUSIONS: The overall findings suggest that while there may be benefits to scar massage in reducing pain, increasing movement and improving scar characteristics; there is a lack of consistent research methods, intervention protocols and outcome measures. This scoping review highlights the heterogenous nature of research into scar massage following surgery and supports the need for further research to substantiate its use in the clinical setting.


Asunto(s)
Cicatriz , Masaje , Cicatriz/terapia , Humanos , Masaje/métodos , Evaluación de Resultado en la Atención de Salud , Dolor
6.
Bioorg Med Chem Lett ; 30(16): 127291, 2020 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-32631513

RESUMEN

Hydroxamic acid-based histone deacetylase inhibitors (HDACi) are a class of epigenetic agents with potentially broad therapeutic application to several disease states including post angioplasty mediated neointimal hyperplasia (NIH). Precise spatiotemporal control over the release of HDACi at the target blood vessel site is required for the safe and successful therapeutic use of HDACi in the setting of drug eluting balloon catheter (DEBc) angioplasty treatment of NIH. We aimed to develop and characterise a novel photoactive HDACi, as a potential coating agent for DEBc. Metacept-3 1 was caged with a photo-labile protecting group (PPG) to synthesise a novel UV365nm active HDACi, caged metacept-3 15. Conversion of caged metacept-3 15 to active/native metacept-3 1 by UV365nm was achievable in significant quantities and at UV365nm power levels in the milliwatt (mW) range. In vitro evaluation of the biological activity of pre and post UV365nm activation of caged metacept-3 15 identified significant HDACi activity in samples exposed to short duration, mW range UV365nm. Toxicity studies performed in human umbilical vein endothelial cells (HUVEC's) identified significantly reduced toxicity of caged metacept-3 15 pre UV365nm exposure compared with native metacept-3 1 and paclitaxel (PTX). Taken together these findings identify a novel photo-activated HDACi, caged metacept-3 15, with pharmacokinetic activation characteristics and biological properties which may make it suitable for evaluation as a novel coating for targeted DEBc angioplasty interventions.


Asunto(s)
Inhibidores de Histona Desacetilasas/farmacología , Ácidos Hidroxámicos/farmacología , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/química , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Humanos , Ácidos Hidroxámicos/síntesis química , Ácidos Hidroxámicos/química , Estructura Molecular , Fotólisis , Relación Estructura-Actividad
7.
J Biol Chem ; 293(30): 11928-11943, 2018 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-29899115

RESUMEN

The development of fast-acting and highly stable insulin analogues is challenging. Insulin undergoes structural transitions essential for binding and activation of the insulin receptor (IR), but these conformational changes can also affect insulin stability. Previously, we substituted the insulin A6-A11 cystine with a rigid, non-reducible C=C linkage ("dicarba" linkage). A cis-alkene permitted the conformational flexibility of the A-chain N-terminal helix necessary for high-affinity IR binding, resulting in surprisingly rapid activity in vivo Here, we show that, unlike the rapidly acting LysB28ProB29 insulin analogue (KP insulin), cis-dicarba insulin is not inherently monomeric. We also show that cis-dicarba KP insulin lowers blood glucose levels even more rapidly than KP insulin, suggesting that an inability to oligomerize is not responsible for the observed rapid activity onset of cis-dicarba analogues. Although rapid-acting, neither dicarba species is stable, as assessed by fibrillation and thermodynamics assays. MALDI analyses and molecular dynamics simulations of cis-dicarba insulin revealed a previously unidentified role of the A6-A11 linkage in insulin conformational dynamics. By controlling the conformational flexibility of the insulin B-chain helix, this linkage affects overall insulin structural stability. This effect is independent of its regulation of the A-chain N-terminal helix flexibility necessary for IR engagement. We conclude that high-affinity IR binding, rapid in vivo activity, and insulin stability can be regulated by the specific conformational arrangement of the A6-A11 linkage. This detailed understanding of insulin's structural dynamics may aid in the future design of rapid-acting insulin analogues with improved stability.


Asunto(s)
Hipoglucemiantes/química , Hipoglucemiantes/farmacología , Insulina/análogos & derivados , Insulina/farmacología , Animales , Glucemia/metabolismo , Línea Celular , Cristalografía por Rayos X , Cisteína/química , Cisteína/farmacología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Simulación de Dinámica Molecular , Células 3T3 NIH , Conformación Proteica , Estabilidad Proteica , Receptor de Insulina/metabolismo , Termodinámica
8.
Drug Metab Dispos ; 47(7): 715-723, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31048454

RESUMEN

Although overexpression of multiple ATP-binding cassette transporters has been reported in clinical samples, few studies have examined how coexpression of multiple transporters affected resistance to chemotherapeutic drugs. We therefore examined how coexpression of ABCB1 (P-glycoprotein) and ABCG2 contributes to drug resistance in a cell line model. HEK293 cells were transfected with vector-encoding full-length ABCB1, ABCG2, or a bicistronic vector containing both genes, each under the control of a separate promoter. Cells transfected with both transporters (B1/G2 cells) demonstrated high levels of both transporters, and uptake of both the ABCB1-specific substrate rhodamine 123 and the ABCG2-specific substrate pheophorbide a was reduced when examined by flow cytometry. B1/G2 cells were also cross-resistant to the ABCB1 substrate doxorubicin, the ABCG2 substrate topotecan, as well as mitoxantrone and the cell cycle checkpoint kinase 1 inhibitor prexasertib, both of which were found to be substrates of both ABCB1 and ABCG2. When B1/G2 cells were incubated with both rhodamine 123 and pheophorbide a, transport of both compounds was observed, suggesting that ABCB1 and ABCG2, when coexpressed, can function independently to transport substrates. ABCB1 and ABCG2 also functioned additively to transport the common fluorescent substrates mitoxantrone and BODIPY-prazosin, as it was necessary to inhibit both transporters to prevent efflux from B1/G2 cells. ABCG2 expression was also found to decrease the efficacy of the ABCB1 inhibitor tariquidar in B1/G2 cells. Thus, ABCB1 and ABCG2 can independently and additively confer resistance to substrates, underscoring the need to inhibit multiple transporters when they are coexpressed.


Asunto(s)
Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/metabolismo , Proteínas de Neoplasias/metabolismo , Subfamilia B de Transportador de Casetes de Unión a ATP/antagonistas & inhibidores , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Antineoplásicos/farmacología , Transporte Biológico , Supervivencia Celular/efectos de los fármacos , Células HEK293 , Humanos , Modelos Biológicos , Proteínas de Neoplasias/genética , Quinolinas/farmacología
9.
Chemistry ; 25(32): 7613-7617, 2019 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-30977166

RESUMEN

Fluorine-18 is the most utilized radioisotope in positron emission tomography (PET), but the wide application of fluorine-18 radiopharmaceuticals is hindered by its challenging labelling conditions. As such, many potentially important radiotracers remain underutilized. Herein, we describe the use of [18 F]ethenesulfonyl fluoride (ESF) as a novel radiofluoride relay reagent that allows radiofluorination reactions to be performed in minimally equipped satellite nuclear medicine centres. [18 F]ESF has a simple and reliable production route and can be stored on inert cartridges. The cartridges can then be shipped remotely and the trapped [18 F]ESF can be liberated by simple solvent elution. We have tested 18 radiolabelling precursors, inclusive of model and clinically used structures, and most precursors have demonstrated comparable radiofluorination efficiencies to those obtained using a conventionally dried [18 F]fluoride source.

10.
J Labelled Comp Radiopharm ; 61(11): 847-856, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29924425

RESUMEN

Fluorine-18 labelled prosthetic groups (PGs) are often necessary for radiolabelling sensitive biological molecules such as peptides and proteins. Several shortcomings, however, often diminish the final yield of radiotracer. In an attempt to provide higher yielding and operationally efficient tools for radiolabelling biological molecules, we describe herein the first radiochemical synthesis of [18 F]ethenesulfonyl fluoride ([18 F]ESF) and its Michael conjugation with amino acids and proteins. The synthesis of [18 F]ESF was optimised using a microfluidic reactor under both carrier-added (c.a.) and no-carrier-added (n.c.a.) conditions, affording, in a straightforward procedure, 30-50% radiochemical yield (RCY) for c.a. [18 F]ESF and 60-70% RCY for n.c.a. [18 F]ESF. The conjugation reactions were performed at room temperature using 10 mg/mL precursor in aqueous/organic solvent mixtures for 15 min. The radiochemical stability of the final conjugates was evaluated in injectable formulation and rat serum, and resulted strongly substrate dependent and generally poor in rat serum. Therefore, in this work we have optimised a straightforward synthesis of [18 F]ESF and its Michael conjugation with model compounds, without requiring chromatographic purification. However, given the general low stability of the final products, further studies will be required for improving conjugate stability, before assessing the use of this PG for PET imaging.


Asunto(s)
Fluoruros/síntesis química , Fluoruros/metabolismo , Radioisótopos de Flúor/metabolismo , Sulfonas/síntesis química , Sulfonas/metabolismo , Animales , Bovinos , Técnicas de Química Sintética , Estabilidad de Medicamentos , Fluoruros/química , Radioisótopos de Flúor/química , Insulina/metabolismo , Marcaje Isotópico , Láseres de Excímeros , Albúmina Sérica Bovina/metabolismo , Sulfonas/química
11.
N Engl J Med ; 370(16): 1504-13, 2014 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-24679061

RESUMEN

BACKGROUND: Marked activation of the sympathetic nervous system occurs during and after noncardiac surgery. Low-dose clonidine, which blunts central sympathetic outflow, may prevent perioperative myocardial infarction and death without inducing hemodynamic instability. METHODS: We performed a blinded, randomized trial with a 2-by-2 factorial design to allow separate evaluation of low-dose clonidine versus placebo and low-dose aspirin versus placebo in patients with, or at risk for, atherosclerotic disease who were undergoing noncardiac surgery. A total of 10,010 patients at 135 centers in 23 countries were enrolled. For the comparison of clonidine with placebo, patients were randomly assigned to receive clonidine (0.2 mg per day) or placebo just before surgery, with the study drug continued until 72 hours after surgery. The primary outcome was a composite of death or nonfatal myocardial infarction at 30 days. RESULTS: Clonidine, as compared with placebo, did not reduce the number of primary-outcome events (367 and 339, respectively; hazard ratio with clonidine, 1.08; 95% confidence interval [CI], 0.93 to 1.26; P=0.29). Myocardial infarction occurred in 329 patients (6.6%) assigned to clonidine and in 295 patients (5.9%) assigned to placebo (hazard ratio, 1.11; 95% CI, 0.95 to 1.30; P=0.18). Significantly more patients in the clonidine group than in the placebo group had clinically important hypotension (2385 patients [47.6%] vs. 1854 patients [37.1%]; hazard ratio 1.32; 95% CI, 1.24 to 1.40; P<0.001). Clonidine, as compared with placebo, was associated with an increased rate of nonfatal cardiac arrest (0.3% [16 patients] vs. 0.1% [5 patients]; hazard ratio, 3.20; 95% CI, 1.17 to 8.73; P=0.02). CONCLUSIONS: Administration of low-dose clonidine in patients undergoing noncardiac surgery did not reduce the rate of the composite outcome of death or nonfatal myocardial infarction; it did, however, increase the risk of clinically important hypotension and nonfatal cardiac arrest. (Funded by the Canadian Institutes of Health Research and others; POISE-2 ClinicalTrials.gov number, NCT01082874.).


Asunto(s)
Agonistas de Receptores Adrenérgicos alfa 2/uso terapéutico , Clonidina/uso terapéutico , Hipotensión/inducido químicamente , Infarto del Miocardio/prevención & control , Complicaciones Posoperatorias/prevención & control , Procedimientos Quirúrgicos Operativos/mortalidad , Agonistas de Receptores Adrenérgicos alfa 2/efectos adversos , Anciano , Clonidina/efectos adversos , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Atención Perioperativa , Complicaciones Posoperatorias/inducido químicamente , Insuficiencia del Tratamiento
12.
N Engl J Med ; 370(16): 1494-503, 2014 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-24679062

RESUMEN

BACKGROUND: There is substantial variability in the perioperative administration of aspirin in patients undergoing noncardiac surgery, both among patients who are already on an aspirin regimen and among those who are not. METHODS: Using a 2-by-2 factorial trial design, we randomly assigned 10,010 patients who were preparing to undergo noncardiac surgery and were at risk for vascular complications to receive aspirin or placebo and clonidine or placebo. The results of the aspirin trial are reported here. The patients were stratified according to whether they had not been taking aspirin before the study (initiation stratum, with 5628 patients) or they were already on an aspirin regimen (continuation stratum, with 4382 patients). Patients started taking aspirin (at a dose of 200 mg) or placebo just before surgery and continued it daily (at a dose of 100 mg) for 30 days in the initiation stratum and for 7 days in the continuation stratum, after which patients resumed their regular aspirin regimen. The primary outcome was a composite of death or nonfatal myocardial infarction at 30 days. RESULTS: The primary outcome occurred in 351 of 4998 patients (7.0%) in the aspirin group and in 355 of 5012 patients (7.1%) in the placebo group (hazard ratio in the aspirin group, 0.99; 95% confidence interval [CI], 0.86 to 1.15; P=0.92). Major bleeding was more common in the aspirin group than in the placebo group (230 patients [4.6%] vs. 188 patients [3.8%]; hazard ratio, 1.23; 95% CI, 1.01, to 1.49; P=0.04). The primary and secondary outcome results were similar in the two aspirin strata. CONCLUSIONS: Administration of aspirin before surgery and throughout the early postsurgical period had no significant effect on the rate of a composite of death or nonfatal myocardial infarction but increased the risk of major bleeding. (Funded by the Canadian Institutes of Health Research and others; POISE-2 ClinicalTrials.gov number, NCT01082874.).


Asunto(s)
Aspirina/uso terapéutico , Infarto del Miocardio/prevención & control , Inhibidores de Agregación Plaquetaria/uso terapéutico , Complicaciones Posoperatorias/prevención & control , Hemorragia Posoperatoria/inducido químicamente , Procedimientos Quirúrgicos Operativos/mortalidad , Anciano , Aspirina/efectos adversos , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Infarto del Miocardio/epidemiología , Atención Perioperativa , Inhibidores de Agregación Plaquetaria/efectos adversos , Insuficiencia del Tratamiento
13.
J Org Chem ; 82(16): 8497-8505, 2017 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-28696718

RESUMEN

A cross-metathesis protocol has been developed to provide facile access to highly hindered trisubstituted α-branched olefins, which when coupled with a cationic azaspirocyclization reaction, generates the marine alkaloids (-)-fasicularin 2 and a pro-forma synthesis of (-)-lepadiformine A 1.


Asunto(s)
Alcaloides/síntesis química , Tiocianatos/síntesis química , Alcaloides/química , Estructura Molecular , Tiocianatos/química
14.
J Org Chem ; 82(16): 8725-8732, 2017 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-28731342

RESUMEN

The development of an efficient, high yielding six-step convergent synthesis of the semisynthetic alkaloid (-)-perhydrohistrionicotoxin is described. The key transformations include the cross metathesis of a Brønsted-acid masked primary homoallylic amine with a vinyl cyclohexenone and a regioselective palladium catalyzed hydrogenation. This sequence generated the advanced Winterfeldt spirocyclic precursor in 47% overall yield, with a longest linear sequence of five steps.


Asunto(s)
Venenos de Anfibios/síntesis química , Venenos de Anfibios/química , Hidrogenación , Estructura Molecular , Estereoisomerismo
15.
J Org Chem ; 81(5): 1798-805, 2016 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-26799811

RESUMEN

Ruthenium-alkylidene-catalyzed cross-metathesis of a range of homologous alkenylamine salts provides expedient and high-yielding routes to commercially valuable polyamide monomers using a single catalyst, telescopic workup, and mild experimental conditions.

16.
J Org Chem ; 80(18): 9057-63, 2015 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-26280241

RESUMEN

The installation of interlocked dicarba bridges into peptide sequences requires the development of a regioselective and chemoselective methodology. This manuscript describes a one-pot, chemoselective synthesis of three 2,7-diaminosuberic acid derivatives from an alkyne, a cobalt-carbonyl protected alkyne, and an alkene using metathesis and homogeneous hydrogenation catalysis.

17.
J Org Chem ; 80(14): 7205-11, 2015 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-26100533

RESUMEN

A simple and generic approach to access a new family of Ru-alkylidene olefin metathesis catalysts with specialized properties is reported. This strategy utilizes a late stage, utilitarian Hoveyda-type ligand derived from tyrosine, which can be accessed via a multigram-scale synthesis. Further functionalization allows the catalyst properties to be tuned, giving access to modified second-generation Hoveyda-Grubbs-type catalysts. This divergent synthetic approach can be used to access solid-supported catalysts and catalysts that function under solvent-free and aqueous conditions.

18.
J Mol Recognit ; 27(5): 285-95, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24700595

RESUMEN

A new set of ligands based on substituted pyridine and other N-heterocyclic structures, possessing an aliphatic primary amino group tether and an exocyclic sulphur atom, has been prepared and immobilized onto epoxy-activated matrices such as Sepharose 6 Fast Flow®. The derived adsorbents have been evaluated for their utility to capture and purify humanized monoclonal antibodies. Favourable binding properties were assessed from screening assays to determine optimal conditions for the capture and elution of the monoclonal antibodies. Static and dynamic binding experiments were employed to derive the equilibrium dissociation constants KD 's and binding capacities Qmax 's. Typically, the KD values were in the range of 2-5 µM and the Qmax values between 20 and 75 mg mAb/ml resin, depending on the stereo-electronic properties of the substituent in the N-heterocyclic ring structure. The effect of ligand structure on the selectivity of these adsorbents was also investigated, and criteria for their use in the purification of monoclonal antibodies from cell culture supernatants established.


Asunto(s)
Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/aislamiento & purificación , Cromatografía/métodos , Ligandos
19.
JAMA ; 312(21): 2254-64, 2014 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-25399007

RESUMEN

IMPORTANCE: Acute kidney injury, a common complication of surgery, is associated with poor outcomes and high health care costs. Some studies suggest aspirin or clonidine administered during the perioperative period reduces the risk of acute kidney injury; however, these effects are uncertain and each intervention has the potential for harm. OBJECTIVE: To determine whether aspirin compared with placebo, and clonidine compared with placebo, alters the risk of perioperative acute kidney injury. DESIGN, SETTING, AND PARTICIPANTS: A 2 × 2 factorial randomized, blinded, clinical trial of 6905 patients undergoing noncardiac surgery from 88 centers in 22 countries with consecutive patients enrolled between January 2011 and December 2013. INTERVENTIONS: Patients were assigned to take aspirin (200 mg) or placebo 2 to 4 hours before surgery and then aspirin (100 mg) or placebo daily up to 30 days after surgery, and were assigned to take oral clonidine (0.2 mg) or placebo 2 to 4 hours before surgery, and then a transdermal clonidine patch (which provided clonidine at 0.2 mg/d) or placebo patch that remained until 72 hours after surgery. MAIN OUTCOMES AND MEASURES: Acute kidney injury was primarily defined as an increase in serum creatinine concentration from the preoperative concentration by either an increase of 0.3 mg/dL or greater (≥26.5 µmol/L) within 48 hours of surgery or an increase of 50% or greater within 7 days of surgery. RESULTS: Aspirin (n = 3443) vs placebo (n = 3462) did not alter the risk of acute kidney injury (13.4% vs 12.3%, respectively; adjusted relative risk, 1.10; 95% CI, 0.96-1.25). Clonidine (n = 3453) vs placebo (n = 3452) did not alter the risk of acute kidney injury (13.0% vs 12.7%, respectively; adjusted relative risk, 1.03; 95% CI, 0.90-1.18). Aspirin increased the risk of major bleeding. In a post hoc analysis, major bleeding was associated with a greater risk of subsequent acute kidney injury (23.3% when bleeding was present vs 12.3% when bleeding was absent; adjusted hazard ratio, 2.20; 95% CI, 1.72-2.83). Similarly, clonidine increased the risk of clinically important hypotension. In a post hoc analysis, clinically important hypotension was associated with a greater risk of subsequent acute kidney injury (14.3% when hypotension was present vs 11.8% when hypotension was absent; adjusted hazard ratio, 1.34; 95% CI, 1.14-1.58). CONCLUSIONS AND RELEVANCE: Among patients undergoing major noncardiac surgery, neither aspirin nor clonidine administered perioperatively reduced the risk of acute kidney injury. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01082874.


Asunto(s)
Lesión Renal Aguda/prevención & control , Agonistas de Receptores Adrenérgicos alfa 2/administración & dosificación , Aspirina/administración & dosificación , Aspirina/efectos adversos , Clonidina/administración & dosificación , Inhibidores de Agregación Plaquetaria/administración & dosificación , Administración Cutánea , Administración Oral , Agonistas de Receptores Adrenérgicos alfa 2/efectos adversos , Anciano , Clonidina/efectos adversos , Creatinina/sangre , Esquema de Medicación , Femenino , Hemorragia/inducido químicamente , Humanos , Hipotensión/inducido químicamente , Masculino , Persona de Mediana Edad , Atención Perioperativa , Inhibidores de Agregación Plaquetaria/efectos adversos , Complicaciones Posoperatorias , Riesgo
20.
Psychol Rec ; 64(2): 143-150, 2014 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-24976647

RESUMEN

Acute effects of methylenedioxymethamphetamine (MDMA), methamphetamine (MA) and methylphenidate (MPD) were studied using a within-subject, repeated acquisition/performance procedure adapted to the Morris Swim Task. To investigate place learning, the acquisition component consisted of a hidden platform that varied in location across experimental sessions. As a control for drug effects not specific to acquisition, a performance component was included in which the hidden platform was in the same pool location in every experimental session. All three drugs increased escape latencies and swim distances in dose-dependent fashion. However, impairment in the acquisition component was generally observed only at doses that also produced impairment in the performance component, suggesting that effects were not selective to place learning. None of the drugs produced enhancement of learning or performance at any dose. Taken together, the results suggest that acute exposure to these psychomotor stimulants produce global impairment of performance in the Morris task, rather than specific deficits in place learning.

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