63 research outputs found

    Small molecule binding sites on the Ras:SOS complex can be exploited for inhibition of Ras activation.

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    Constitutively active mutant KRas displays a reduced rate of GTP hydrolysis via both intrinsic and GTPase-activating protein-catalyzed mechanisms, resulting in the perpetual activation of Ras pathways. We describe a fragment screening campaign using X-ray crystallography that led to the discovery of three fragment binding sites on the Ras:SOS complex. The identification of tool compounds binding at each of these sites allowed exploration of two new approaches to Ras pathway inhibition by stabilizing or covalently modifying the Ras:SOS complex to prevent the reloading of Ras with GTP. Initially, we identified ligands that bound reversibly to the Ras:SOS complex in two distinct sites, but these compounds were not sufficiently potent inhibitors to validate our stabilization hypothesis. We conclude by demonstrating that covalent modification of Cys118 on Ras leads to a novel mechanism of inhibition of the SOS-mediated interaction between Ras and Raf and is effective at inhibiting the exchange of labeled GDP in both mutant (G12C and G12V) and wild type Ras

    Endovascular Thrombectomy for Ischemic Stroke Increases Disability-Free Survival, Quality of Life, and Life Expectancy and Reduces Cost

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    Background: Endovascular thrombectomy improves functional outcome in large vessel occlusion ischemic stroke. We examined disability, quality of life, survival and acute care costs in the EXTEND-IA trial, which used CT-perfusion imaging selection. Methods: Large vessel ischemic stroke patients with favorable CT-perfusion were randomized to endovascular thrombectomy after alteplase versus alteplase-only. Clinical outcome was prospectively measured using 90-day modified Rankin scale (mRS). Individual patient expected survival and net difference in Disability/Quality-adjusted life years (DALY/QALY) up to 15 years from stroke were modeled using age, sex, 90-day mRS, and utility scores. Level of care within the first 90 days was prospectively measured and used to estimate procedure and inpatient care costs (USreferenceyear2014).Results:Therewere70patients,35ineacharm,meanage69,medianNIHSS15(IQR12−19).Themedian(IQR)disability−weightedutilityscoreat90dayswas0.65(0.00−0.91)inthealteplase−onlyversus0.91(0.65−1.00)intheendovasculargroup(p=0.005).Modeledlifeexpectancywasgreaterintheendovascularversusalteplaseonlygroup(median15.6versus11.2years,p=0.02).TheendovascularthrombectomygrouphadfewersimulatedDALYslostover15years[median(IQR)5.5(3.2−8.7)versus8.9(4.7−13.8),p=0.02]andmoreQALYgained[median(IQR)9.3(4.2−13.1)versus4.9(0.3−8.5),p=0.03].Endovascularpatientsspentlesstimeinhospital[median(IQR)5(3−11)daysversus8(5−14)days,p=0.04]andrehabilitation[median(IQR)0(0−28)versus27(0−65)days,p=0.03].Theestimatedinpatientcostsinthefirst90dayswerelessinthethrombectomygroup(averageUS reference year 2014). Results: There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15 (IQR 12-19). The median (IQR) disability-weighted utility score at 90 days was 0.65 (0.00-0.91) in the alteplase-only versus 0.91 (0.65-1.00) in the endovascular group (p = 0.005). Modeled life expectancy was greater in the endovascular versus alteplaseonly group (median 15.6 versus 11.2 years, p = 0.02). The endovascular thrombectomy group had fewer simulated DALYs lost over 15 years [median (IQR) 5.5 (3.2-8.7) versus 8.9 (4.7-13.8), p = 0.02] and more QALY gained [median (IQR) 9.3 (4.2-13.1) versus 4.9 (0.3-8.5), p = 0.03]. Endovascular patients spent less time in hospital [median (IQR) 5 (3-11) days versus 8 (5-14) days, p = 0.04] and rehabilitation [median (IQR) 0 (0-28) versus 27 (0-65) days, p = 0.03]. The estimated inpatient costs in the first 90 days were less in the thrombectomy group (average US15,689 versus US30,569,p=0.008)offsettingthecostsofinterhospitaltransportandthethrombectomyprocedure(averageUS30,569, p = 0.008) offsetting the costs of interhospital transport and the thrombectomy procedure (average US10,515). The average saving per patient treated with thrombectomy was US$4,365. c Conclusion: Thrombectomy patients with large vessel occlusion and salvageable tissue on CT-perfusion had reduced length of stay and overall costs to 90 days. There was evidence of clinically relevant improvement in long-term survival and quality of life.Peer reviewe

    Endovascular thrombectomy for ischemic stroke increases disability-free survival, quality of life, and life expectancy and reduces cost

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    Background: Endovascular thrombectomy improves functional outcome in large vessel occlusion ischemic stroke. We examined disability, quality of life, survival and acute care costs in the EXTEND-IA trial, which used CT-perfusion imaging selection. Methods: Large vessel ischemic stroke patients with favorable CT-perfusion were randomized to endovascular thrombectomy after alteplase versus alteplase-only. Clinical outcome was prospectively measured using 90-day modified Rankin scale (mRS). Individual patient expected survival and net difference in Disability/Quality-adjusted life years (DALY/QALY) up to 15 years from stroke were modeled using age, sex, 90-day mRS, and utility scores. Level of care within the first 90 days was prospectively measured and used to estimate procedure and inpatient care costs (USreferenceyear2014).Results:Therewere70patients,35ineacharm,meanage69,medianNIHSS15(IQR12–19).Themedian(IQR)disability−weightedutilityscoreat90dayswas0.65(0.00–0.91)inthealteplase−onlyversus0.91(0.65–1.00)intheendovasculargroup(p=0.005).Modeledlifeexpectancywasgreaterintheendovascularversusalteplase−onlygroup(median15.6versus11.2years,p=0.02).TheendovascularthrombectomygrouphadfewersimulatedDALYslostover15years[median(IQR)5.5(3.2–8.7)versus8.9(4.7–13.8),p=0.02]andmoreQALYgained[median(IQR)9.3(4.2–13.1)versus4.9(0.3–8.5),p=0.03].Endovascularpatientsspentlesstimeinhospital[median(IQR)5(3–11)daysversus8(5–14)days,p=0.04]andrehabilitation[median(IQR)0(0–28)versus27(0–65)days,p=0.03].Theestimatedinpatientcostsinthefirst90dayswerelessinthethrombectomygroup(averageUS reference year 2014). Results: There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15 (IQR 12–19). The median (IQR) disability-weighted utility score at 90 days was 0.65 (0.00–0.91) in the alteplase-only versus 0.91 (0.65–1.00) in the endovascular group (p = 0.005). Modeled life expectancy was greater in the endovascular versus alteplase-only group (median 15.6 versus 11.2 years, p = 0.02). The endovascular thrombectomy group had fewer simulated DALYs lost over 15 years [median (IQR) 5.5 (3.2–8.7) versus 8.9 (4.7–13.8), p = 0.02] and more QALY gained [median (IQR) 9.3 (4.2–13.1) versus 4.9 (0.3–8.5), p = 0.03]. Endovascular patients spent less time in hospital [median (IQR) 5 (3–11) days versus 8 (5–14) days, p = 0.04] and rehabilitation [median (IQR) 0 (0–28) versus 27 (0–65) days, p = 0.03]. The estimated inpatient costs in the first 90 days were less in the thrombectomy group (average US15,689 versus US30,569,p=0.008)offsettingthecostsofinterhospitaltransportandthethrombectomyprocedure(averageUS30,569, p = 0.008) offsetting the costs of interhospital transport and the thrombectomy procedure (average US10,515). The average saving per patient treated with thrombectomy was US$4,365. Conclusion: Thrombectomy patients with large vessel occlusion and salvageable tissue on CT-perfusion had reduced length of stay and overall costs to 90 days. There was evidence of clinically relevant improvement in long-term survival and quality of life.Bruce C. V. Campbell, Peter J. Mitchell, Leonid Churilov, Mahsa Keshtkaran, Keun-Sik Hong, Timothy J. Kleinig … et al. on behalf of the EXTEND-IA Investigator

    Discovery of 4,6-disubstituted pyrimidines as potent inhibitors of the heat shock factor 1 (HSF1) stress pathway and CDK9.

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    Heat shock factor 1 (HSF1) is a transcription factor that plays key roles in cancer, including providing a mechanism for cell survival under proteotoxic stress. Therefore, inhibition of the HSF1-stress pathway represents an exciting new opportunity in cancer treatment. We employed an unbiased phenotypic screen to discover inhibitors of the HSF1-stress pathway. Using this approach we identified an initial hit (1) based on a 4,6-pyrimidine scaffold (2.00 μM). Optimisation of cellular SAR led to an inhibitor with improved potency (25, 15 nM) in the HSF1 phenotypic assay. The 4,6-pyrimidine 25 was also shown to have high potency against the CDK9 enzyme (3 nM)

    Midterm outcomes of paclitaxel-eluting stents for the treatment of intracranial posterior circulation stenoses

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    OBJECT: Symptomatic intracranial vertebral and basilar artery atherosclerotic stenoses carry a high risk of stroke and permanent disability if refractory to maximal medical therapy. The authors conducted a study to determine the technical feasibility and midterm clinical and angiographic outcomes in patients in whom paclitaxel-eluting stents were placed for the treatment of symptomatic intracranial posterior circulation stenoses. METHODS: A retrospective review of medical records and imaging studies was performed for 13 consecutive patients in whom paclitaxel-coated stents were used to treat symptomatic posterior circulation intracranial stenoses between 2002 and 2005. Clinical follow-up data were supplemented by telephone interviews. The technical success rate for stent placement was 100%. One patient (8%) suffered a periprocedural stroke. Twelve patients (92%) underwent clinical follow up for a minimum of 3 months postsurgery, and 11 (92%) of these patients remained asymptomatic after a mean period of 10.9 months. Nine patients (69%) underwent catheter angiographic follow up, and no patient had significant in-stent recurrence of stenosis after a mean period of 5.4 months. CONCLUSIONS: Treatment of intracranial posterior circulation stenoses with drug-eluting stents is technically feasible, and the rate of clinically significant periprocedural complications is low. Rates of stenosis recurrence are reduced compared with those of bare-metal stents in the midterm. Midterm clinical outcome is excellent; no symptom recurrence was observed in this patient cohort.4 page(s
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