44 research outputs found
Total Synthesis of Brasoside and Littoralisone
The first total syntheses of littoralisone (1) and brasoside (2) have been achieved in 13 overall steps. Both natural products are forged from a common intermediate which is rapidly assembled using organocatalytic technology, including a proline-catalyzed α-aminoxylation and a contra-thermodynamic intramolecular Michael addition. Application of the two-step carbohydrate synthesis technology has enabled to access a selectively substituted glucose derivative for use as an intramolecular cycloaddition tether. This synthesis culminates with an intramolecular [2+2] photocycloaddition that serves to support the proposed biosynthetic origins of 1 from 2
Mass Activated Droplet Sorting (MADS) Enables Highâ Throughput Screening of Enzymatic Reactions at Nanoliter Scale
Microfluidic droplet sorting enables the highâ throughput screening and selection of waterâ inâ oil microreactors at speeds and volumes unparalleled by traditional wellâ plate approaches. Most such systems sort using fluorescent reporters on modified substrates or reactions that are rarely industrially relevant. We describe a microfluidic system for highâ throughput sorting of nanoliter droplets based on direct detection using electrospray ionization mass spectrometry (ESIâ MS). Droplets are split, one portion is analyzed by ESIâ MS, and the second portion is sorted based on the MS result. Throughput of 0.7â samplesâ sâ 1 is achieved with 98â % accuracy using a selfâ correcting and adaptive sorting algorithm. We use the system to screen â 15â 000â samples in 6â h and demonstrate its utility by sorting 25â nL droplets containing transaminase expressed in vitro. Labelâ free ESIâ MS droplet screening expands the toolbox for droplet detection and recovery, improving the applicability of droplet sorting to protein engineering, drug discovery, and diagnostic workflows.A microfluidic system for sorting nanoliter droplets based on mass spectrometry is presented. Fully automated, labelâ free sorting at 0.7â samplesâ sâ 1 is achieved with 98â % accuracy. In vitro transcription and translation (ivTT) of a transaminase enzyme in ca.â 25â nL samples is demonstrated and samples are sorted on the basis of enzyme activity.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154315/1/anie201913203.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154315/2/anie201913203-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154315/3/anie201913203_am.pd
Mass Activated Droplet Sorting (MADS) Enables Highâ Throughput Screening of Enzymatic Reactions at Nanoliter Scale
Microfluidic droplet sorting enables the highâ throughput screening and selection of waterâ inâ oil microreactors at speeds and volumes unparalleled by traditional wellâ plate approaches. Most such systems sort using fluorescent reporters on modified substrates or reactions that are rarely industrially relevant. We describe a microfluidic system for highâ throughput sorting of nanoliter droplets based on direct detection using electrospray ionization mass spectrometry (ESIâ MS). Droplets are split, one portion is analyzed by ESIâ MS, and the second portion is sorted based on the MS result. Throughput of 0.7â samplesâ sâ 1 is achieved with 98â % accuracy using a selfâ correcting and adaptive sorting algorithm. We use the system to screen â 15â 000â samples in 6â h and demonstrate its utility by sorting 25â nL droplets containing transaminase expressed in vitro. Labelâ free ESIâ MS droplet screening expands the toolbox for droplet detection and recovery, improving the applicability of droplet sorting to protein engineering, drug discovery, and diagnostic workflows.Ein Mikrofluidiksystem zur Sortierung von Nanolitertröpfchen basierend auf Massenspektrometrie erreicht eine vollautomatische markierungsfreie Sortierung bei 0.7 Probenâ sâ 1 mit 98â % Genauigkeit. Die Inâ vitroâ Transkription und â Translation (ivTT) eines Transaminaseâ Enzyms in Proben von etwa 25â nL wird demonstriert, und die Proben werden nach ihrer Enzymaktivität sortiert.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154446/1/ange201913203-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154446/2/ange201913203.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154446/3/ange201913203_am.pd
Sex-based associations with microvascular injury and outcomes after ST-segment elevation myocardial infarction
Objectives: We aimed to assess for sex differences in invasive parameters of acute microvascular reperfusion injury and infarct characteristics on cardiac MRI after ST-segment elevation myocardial infarction (STEMI).
Methods: Patients with STEMI undergoing emergency percutaneous coronary intervention (PCI) were prospectively enrolled. Index of microcirculatory resistance (IMR) and coronary flow reserve (CFR) were measured in the culprit artery post-PCI. Contrast-enhanced MRI was used to assess infarct characteristics, microvascular obstruction and myocardial haemorrhage, 2 days and 6 months post-STEMI. Prespecified outcomes were as follows: (i) all-cause death/first heart failure hospitalisation and (ii) cardiac death/non-fatal myocardial infarction/urgent coronary revascularisation (major adverse cardiovascular event, MACE) during 5- year median follow-up.
Results: In 324 patients with STEMI (87 women, mean age: 61 ± 12.19 years; 237 men, mean age: 59 ± 11.17 years), women had anterior STEMI less often, fewer prescriptions of beta-blockers at discharge and higher baseline N-terminal pro-B-type natriuretic peptide levels (all p < 0.05). Following emergency PCI, fewer women than men had Thrombolysis in Myocardial Infarction (TIMI) myocardial perfusion grades ≤ 1 (20% vs 32%, p = 0.027) and women had lower corrected TIMI frame counts (12.94 vs 17.65, p = 0.003). However, IMR, CFR, microvascular obstruction, myocardial haemorrhage, infarct size, myocardial salvage index, left ventricular remodelling and ejection fraction did not differ significantly between sexes. Female sex was not associated with MACE or all-cause death/first heart failure hospitalisation.
Conclusion: There were no sex differences in microvascular pathology in patients with acute STEMI. Women had less anterior infarcts than men, and beta-blocker therapy at discharge was prescribed less often in women
Hypertension, Microvascular Pathology, and Prognosis After an Acute Myocardial Infarction
The rationale for our study was to investigate the pathophysiology of microvascular injury in patients with acute ST-segment–elevation myocardial infarction in relation to a history of hypertension. We undertook a cohort study using invasive and noninvasive measures of microvascular injury, cardiac magnetic resonance imaging at 2 days and 6 months, and assessed health outcomes in the longer term (URL: http://www.clinicaltrials.gov. Unique identifier: NCT02072850). Three hundred twenty-four patients with acute myocardial infarction (mean age, 59 [12] years; blood pressure, 135 [25] / 79 [14] mm Hg; 237 [73%] male, 105 [32%] with antecedent hypertension) were prospectively enrolled during emergency percutaneous coronary intervention. Compared with patients without antecedent hypertension, patients with hypertension were older (63 [12] years versus 57 [11] years; P<0.001) and a lower proportion were cigarette smokers (52 [50%] versus 144 [66%]; P=0.007). Coronary blood flow, microvascular resistance within the culprit artery, infarct pathologies, inflammation (C-reactive protein and interleukin-6) were not associated with hypertension. Compared with patients without antecedent hypertension, patients with hypertension had less improvement in left ventricular ejection fraction at 6 months from baseline (5.3 [8.2]% versus 7.4 [7.6]%; P=0.040). Antecedent hypertension was a multivariable associate of incident myocardial hemorrhage 2-day post-MI (1.81 [0.98–3.34]; P=0.059) and all-cause death or heart failure (n=47 events, n=24 with hypertension; 2.53 [1.28–4.98]; P=0.007) postdischarge (median follow-up 4 years). Severe progressive microvascular injury is implicated in the pathophysiology and prognosis of patients with a history of hypertension and acute myocardial infarction
Invasive versus medical management in patients with prior coronary artery bypass surgery with a non-ST segment elevation acute coronary syndrome: a pilot randomized controlled trial
Background:
The benefits of routine invasive management in patients with prior coronary artery bypass grafts presenting with non-ST elevation acute coronary syndromes are uncertain because these patients were excluded from pivotal trials.
Methods:
In a multicenter trial, non-ST elevation acute coronary syndromes patients with prior coronary artery bypass graft were prospectively screened in 4 acute hospitals. Medically stabilized patients were randomized to invasive management (invasive group) or noninvasive management (medical group). The primary outcome was adherence with the randomized strategy by 30 days. A blinded, independent Clinical Event Committee adjudicated predefined composite outcomes for efficacy (all-cause mortality, rehospitalization for refractory ischemia/angina, myocardial infarction, hospitalization because of heart failure) and safety (major bleeding, stroke, procedure-related myocardial infarction, and worsening renal function).
Results:
Two hundred seventeen patients were screened and 60 (mean±SD age, 71±9 years, 72% male) were randomized (invasive group, n=31; medical group, n=29). One-third (n=10) of the participants in the invasive group initially received percutaneous coronary intervention. In the medical group, 1 participant crossed over to invasive management on day 30 but percutaneous coronary intervention was not performed. During 2-years’ follow-up (median [interquartile range], 744 [570–853] days), the composite outcome for efficacy occurred in 13 (42%) subjects in the invasive group and 13 (45%) subjects in the medical group. The composite safety outcome occurred in 8 (26%) subjects in the invasive group and 9 (31%) subjects in the medical group. An efficacy or safety outcome occurred in 17 (55%) subjects in the invasive group and 16 (55%) subjects in the medical group. Health status (EuroQol 5 Dimensions) and angina class in each group were similar at 12 months.
Conclusions:
More than half of the population experienced a serious adverse event. An initial noninvasive management strategy is feasible. A substantive health outcomes trial of invasive versus noninvasive management in non-ST elevation acute coronary syndromes patients with prior coronary artery bypass grafts appears warranted.
Clinical Trial Registration:
URL: https://www.clinicaltrials.gov. Unique identifier: NCT01895751
Current Smoking and Prognosis After Acute ST-Segment Elevation Myocardial Infarction:New Pathophysiological Insights
Objectives:
The aim of this study was to mechanistically investigate associations among cigarette smoking, microvascular pathology, and longer term health outcomes in patients with acute ST-segment elevation myocardial infarction (MI).
Background:
The pathophysiology of myocardial reperfusion injury and prognosis in smokers with acute ST-segment elevation MI is incompletely understood.
Methods:
Patients were prospectively enrolled during emergency percutaneous coronary intervention. Microvascular function in the culprit artery was measured invasively. Contrast-enhanced magnetic resonance imaging (1.5-T) was performed 2 days and 6 months post-MI. Infarct size and microvascular obstruction were assessed using late gadolinium enhancement imaging. Myocardial hemorrhage was assessed with T2* mapping. Pre-specified endpoints included: 1) all-cause death or first heart failure hospitalization; and 2) cardiac death, nonfatal MI, or urgent coronary revascularization (major adverse cardiovascular events). Binary logistic regression (odds ratio [OR] with 95% confidence interval [CI]) with smoking status was used.
Results:
In total, 324 patients with ST-segment elevation MI were enrolled (mean age 59 years, 73% men, 60% current smokers). Current smokers were younger (55 ± 11 years vs. 65 ± 10 years, p < 0.001), with fewer patients with hypertension (52 ± 27% vs. 53 ± 41%, p = 0.007). Smokers had better TIMI (Thrombolysis In Myocardial Infarction) flow grade (≥2 vs. ≤1, p = 0.024) and ST-segment resolution (none vs. partial vs. complete, p = 0.010) post–percutaneous coronary intervention. On day 1, smokers had higher circulating C-reactive protein, neutrophil, and monocyte levels. Two days post-MI, smoking independently predicted infarct zone hemorrhage (OR: 2.76; 95% CI: 1.42 to 5.37; p = 0.003). After a median follow-up period of 4 years, smoking independently predicted all-cause death or heart failure events (OR: 2.20; 95% CI: 1.07 to 4.54) and major adverse cardiovascular events (OR: 2.79; 95% CI: 2.30 to 5.99).
Conclusions:
Smoking is associated with enhanced inflammation acutely, infarct-zone hemorrhage subsequently, and longer term adverse cardiac outcomes. Inflammation and irreversible myocardial hemorrhage post-MI represent mechanistic drivers for adverse long-term prognosis in smokers. (Detection and Significance of Heart Injury in ST Elevation Myocardial Infarction. [BHF MR-MI]; NCT02072850)
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Chronic infarct size after spontaneous coronary artery dissection: implications for pathophysiology and clinical management
Aims:
To report the extent and distribution of myocardial injury and its impact on left ventricular systolic function with cardiac magnetic resonance imaging (CMR) following spontaneous coronary artery dissection (SCAD) and to investigate predictors of myocardial injury.
Methods and results:
One hundred and fifty-eight angiographically confirmed SCAD-survivors (98% female) were phenotyped by CMR and compared in a case–control study with 59 (97% female) healthy controls (44.5 ± 8.4 vs. 45.0 ± 9.1 years). Spontaneous coronary artery dissection presentation was with non-ST-elevation myocardial infarction in 95 (60.3%), ST-elevation myocardial infarction (STEMI) in 52 (32.7%), and cardiac arrest in 11 (6.9%). Left ventricular function in SCAD-survivors was generally well preserved with small reductions in ejection fraction (57 ± 7.2% vs. 60 ± 4.9%, P < 0.01) and increases in left ventricular dimensions (end-diastolic volume: 85 ± 14 mL/m2 vs. 80 ± 11 mL/m2, P < 0.05; end-systolic volume: 37 ± 11 mL/m2 vs. 32 ± 7 mL/m2, P <0.01) compared to healthy controls. Infarcts were small with few large infarcts (median 4.06%; range 0–30.9%) and 39% having no detectable late gadolinium enhancement (LGE). Female SCAD patients presenting with STEMI had similar sized infarcts to female Type-1 STEMI patients age <75 years. Multivariate modelling demonstrated STEMI at presentation, initial TIMI 0/1 flow, multivessel SCAD, and a Beighton score >4 were associated with larger infarcts [>10% left ventricular (LV) mass].
Conclusion:
The majority of patients presenting with SCAD have no or small infarctions and preserved ejection fraction. Patients presenting with STEMI, TIMI 0/1 flow, multivessel SCAD and those with features of connective tissue disorders are more likely to have larger infarcts