86 research outputs found

    A Snu114-GTP-Prp8 module forms a relay station for efficient splicing in yeast

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    The single G protein of the spliceosome, Snu114, has been proposed to facilitate splicing as a molecular motor or as a regulatory G protein. However, available structures of spliceosomal complexes show Snu114 in the same GTP-bound state, and presently no Snu114 GTPase-regulatory protein is known. We determined a crystal structure of Snu114 with a Snu114-binding region of the Prp8 protein, in which Snu114 again adopts the same GTP-bound conformation seen in spliceosomes. Snu114 and the Snu114-Prp8 complex co-purified with endogenous GTP. Snu114 exhibited weak, intrinsic GTPase activity that was abolished by the Prp8 Snu114-binding region. Exchange of GTP-contacting residues in Snu114, or of Prp8 residues lining the Snu114 GTP-binding pocket, led to temperature-sensitive yeast growth and affected the same set of splicing events in vivo. Consistent with dynamic Snu114-mediated protein interactions during splicing, our results suggest that the Snu114-GTP-Prp8 module serves as a relay station during spliceosome activation and disassembly, but that GTPase activity may be dispensable for splicing

    Treatment and Management of Upper Extremity Dysfunction Following Transradial Percutaneous Coronary Intervention:A Prospective Cohort Study

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    Background:The transradial artery access is the benchmark approach in transradial percutaneous coronary intervention (TR-PCI). The purpose of this study was to evaluate the different complications, treatments, and outcome of upper extremity dysfunction following a TR-PCI.Methods:This was a prospective cohort substudy of patients with access-site complications. The study population consisted of 433 patients treated with TR-PCI. Referral to the hand center was mandated if the patient experienced new-onset or increase of preexistent symptoms in the upper extremity. Patients were followed up to the last control visit (5-7 months after the index procedure) at the hand center. Outcome results were categorized in "symptom-free," "improvement of symptoms," and "no improvement."Results:Forty-one (9% of total) patients underwent assessment at the hand center. Most frequent referral indication was pain in the intervention arm. Women, preexisting sensibility disorder, and osteoarthritis in the intervention arm were associated with increased odds of referral. The most common complications diagnosed were carpal tunnel syndrome (n = 18) and osteoarthritis (n = 15). Thirty patients required further medical treatment. Immobilization therapy was most applied. Seventeen (4% of total) patients had persisting symptoms despite medical treatment.Conclusions:The occurrence of complications in the upper extremity after a TR-PCI is small. Despite medical treatment, symptoms persisted in 4% of all patients treated with TR-PCI. Possible explanations for the persisting symptoms are exacerbation of latent osteoarthritis and carpal tunnel syndrome by trauma-induced edema. Awareness of TR-PCI-induced complications among all specialists is essential to optimize patient care

    Personality traits, ventricular tachyarrhythmias, and mortality in patients with an implantable cardioverter defibrillator: 6 years follow-up of the WEBCARE cohort

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    Objective: Risk stratification within the ICD population warrants the examining of the role of protective- and risk factors. Current study examines the association between Type D personality, pessimism, and optimism and risk of ventricular tachyarrhythmias (VTa's) and mortality in patients with a first-time ICD 6 years post implantation. Methods: A total of 221 first-implant ICD patients completed questionnaires on optimism and pessimism (Life Orientation Test) and Type D personality (Type D scale DS14) 10 to 14 days after implantation. VTa's and all-cause mortality 6 years post implant comprised the study endpoints. Results: Ninety (40.7%) patients had experienced VTa's and 37 (16.7%) patients died, 12 (5.4%) due to a cardiac cause. Adjusted logistic regression analysis showed that pessimism was significantly associated with increased risk of VTa's (OR = 1.09; 95% CI = 1.00–1.19; p =.05). Type D personality (OR = 1.05; 95% CI = 0.47–2.32; p =.91) and optimism (OR = 1.00; 95% CI = 0.90–1.12; p =.98) were not associated with VTa's. None of the personality types were associated with mortality. Conclusion: Pessimism was associated with VTa's but not with mortality. No significant association with either of the endpoints was observed for Type D personality and optimism. Future research should focus on the coexistent psychosocial factors that possibly lead to adverse cardiac prognosis in this patient population

    Pupillary Responses to High-Irradiance Blue Light Correlate with Glaucoma Severity

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    PurposeTo evaluate whether a chromatic pupillometry test can be used to detect impaired function of intrinsically photosensitive retinal ganglion cells (ipRGCs) in patients with primary open-angle glaucoma (POAG) and to determine if pupillary responses correlate with optic nerve damage and visual loss.DesignCross-sectional study.ParticipantsOne hundred sixty-one healthy controls recruited from a community polyclinic (55 men; 151 ethnic Chinese) and 40 POAG patients recruited from a glaucoma clinic (22 men; 35 ethnic Chinese) 50 years of age or older.MethodsSubjects underwent monocular exposure to narrowband blue light (469 nm) or red light (631 nm) using a modified Ganzfeld dome. Each light stimulus was increased gradually over 2 minutes to activate sequentially the rods, cones, and ipRGCs that mediate the pupillary light reflex. Pupil diameter was recorded using an infrared pupillography system.Main Outcome MeasuresPupillary responses to blue light and red light were compared between control subjects and those with POAG by constructing dose-response curves across a wide range of corneal irradiances (7–14 log photons/cm2 per second). In patients with POAG, pupillary responses were evaluated relative to standard automated perimetry testing (Humphrey Visual Field [HVF]; Carl Zeiss Meditec, Dublin, CA) and scanning laser ophthalmoscopy parameters (Heidelberg Retinal Tomography [HRT]; Heidelberg Engineering, Heidelberg, Germany).ResultsThe pupillary light reflex was reduced in patients with POAG only at higher irradiance levels, corresponding to the range of activation of ipRGCs. Pupillary responses to high-irradiance blue light associated more strongly with disease severity compared with responses to red light, with a significant linear correlation observed between pupil diameter and HVF mean deviation (r = −0.44; P = 0.005) as well as HRT linear cup-to-disc ratio (r = 0.61; P < 0.001) and several other optic nerve head parameters.ConclusionsIn glaucomatous eyes, reduced pupillary responses to high-irradiance blue light were associated with greater visual field loss and optic disc cupping. In POAG, a short chromatic pupillometry test that evaluates the function of ipRGCs can be used to estimate the degree of damage to retinal ganglion cells that mediate image-forming vision. This approach could prove useful in detecting glaucoma

    Treatment and Management of Upper Extremity Dysfunction Following Transradial Percutaneous Coronary Intervention: A Prospective Cohort Study

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    Background: The transradial artery access is the benchmark approach in transradial percutaneous coronary intervention (TR-PCI). The purpose of this study was to evaluate the different complications, treatments, and outcome of upper extremity dysfunction following a TR-PCI. Methods: This was a prospective cohort substudy of patients with access-site complications. The study population consisted of 433 patients treated with TR-PCI. Referral to the hand center was mandated if the patient experienced new-onset or increase of preexistent symptoms in the upper extremity. Patients were followed up to the last control visit (5-7 months after the index procedure) at the hand center. Outcome results were categorized in “symptom-free,” “improvement of symptoms,” and “no improvement.” Results: Forty-one (9% of total) patients underwent assessment at the hand center. Most frequent referral indication was pain in the intervention arm. Women, preexisting sensibility disorder, and osteoarthritis in the intervention arm were associated with increased odds of referral. The most common complications diagnosed were carpal tunnel syndrome (n = 18) and osteoarthritis (n = 15). Thirty patients required further medical treatment. Immobilization therapy was most applied. Seventeen (4% of total) patients had persisting symptoms despite medical treatment. Conclusions: The occurrence of complications in the upper extremity after a TR-PCI is small. Despite medical treatment, symptoms persisted in 4% of all patients treated with TR-PCI. Possible explanations for the persisting symptoms are exacerbation of latent osteoarthritis and carpal tunnel syndrome by trauma-induced edema. Awareness of TR-PCI-induced complications among all specialists is essential to optimize patient care

    Targeted therapy of underlying conditions improves sinus rhythm maintenance in patients with persistent atrial fibrillation:Results of the RACE 3 trial

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    Aims: Atrial fibrillation (AF) is a progressive disease. Targeted therapy of underlying conditions refers to interventions aiming to modify risk factors in order to prevent AF. We hypothesised that targeted therapy of underlying conditions improves sinus rhythm maintenance in patients with persistent AF. Methods and results: We randomized patients with early persistent AF and mild-to-moderate heart failure (HF) to targeted therapy of underlying conditions or conventional therapy. Both groups received causal treatment of AF and HF, and rhythm control therapy. In the intervention group, on top of that, four therapies were started: (i) mineralocorticoid receptor antagonists (MRAs), (ii) statins, (iii) angiotensin converting enzyme inhibitors and/or receptor blockers, and (iv) cardiac rehabilitation including physical activity, dietary restrictions, and counselling. The primary endpoint was sinus rhythm at 1 year during 7 days of Holter monitoring. Of 245 patients, 119 were randomized to targeted and 126 to conventional therapy. The intervention led to a contrast in MRA (101 [85%] vs. 5 [4%] patients, P < 0.001) and statin use (111 [93%] vs. 61 [48%], P < 0.001). Angiotensin converting enzyme inhibitors/angiotensin receptor blockers were not different. Cardiac rehabilitation was completed in 109 (92%) patients. Underlying conditions were more successfully treated in the intervention group. At 1 year, sinus rhythm was present in 89 (75%) patients in the intervention vs. 79 (63%) in the conventional group (odds ratio 1.765, lower limit of 95% confidence interval 1.021, P = 0.042). Conclusions: RACE 3 confirms that targeted therapy of underlying conditions improves sinus rhythm maintenance in patients with persistent AF. Trial Registration number: Clinicaltrials.gov NCT00877643

    Rate control efficacy in permanent atrial fibrillation:a comparison between lenient versus strict rate control in patients with and without heart failure. Background, aims, and design of RACE II

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    BACKGROUND: Recent studies demonstrated that rate control is an acceptable alternative for rhythm control in patients with persistent atrial fibrillation (AF). However, optimal heart rate during AF is still unknown. OBJECTIVE: To show that in patients with permanent AF, lenient rate control is not inferior to strict rate control in terms of cardiovascular mortality, morbidity, neurohormonal activation, New York Heart Association class for heart failure, left ventricular function, left atrial size, quality of life, and costs. METHODS: The RACE II study is a prospective multicenter trial in The Netherlands that will randomize 500 patients with permanent AF (< or = 12 months) to strict or lenient rate control. Strict rate control is defined as a mean resting heart rate < 80 beats per minute (bpm) and heart rate during minor exercise < 110 bpm. After reaching the target, a 24-hour Holter monitoring will be performed. If necessary, drug dose reduction and/or pacemaker implantation will be performed. Lenient rate control is defined as a resting heart rate < 110 bpm. Patients will be seen after 1, 2, and 3 months (for titration of rate control drugs) and yearly thereafter. We anticipate a 25% 2.5-year cardiovascular morbidity and mortality in both groups. RESULTS: Enrollment started in January 2005 in 29 centers in The Netherlands and is expected to be concluded in June 2006. Follow-up will be at least 2 years with a maximum of 3 years. CONCLUSION: This study should provide data how to treat patients with permanent AF

    Antiarrhythmic drugs in patients with early persistent atrial fibrillation and heart failure:results of the RACE 3 study

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    Aims: Maintaining sinus rhythm in patients with persistent atrial fibrillation (AF) is challenging. We explored the efficacy of class I and III antiarrhythmic drugs (AADs) in patients with persistent AF and mild to moderate heart failure (HF). Methods and results: In the RACE 3 trial, patients with early persistent symptomatic AF and short history of mild to moderate HF with preserved or reduced left ventricular ejection fraction (LVEF) were randomized to targeted or conventional therapy. Both groups received AF and HF guideline-driven treatment. Additionally, the targeted-group received mineralocorticoid receptor antagonists, statins, angiotensin-converting enzyme inhibitors and/or receptor blockers, and cardiac rehabilitation. Class I and III AADs could be instituted in case of symptomatic recurrent AF. Eventually, pulmonary vein isolation could be performed. Primary endpoint was sinus rhythm on 7-day Holter after 1-year. Included were 245 patients, age 65 ± 9 years, 193 (79%) men, AF history was 3 (2-6) months, HF history 2 (1-4) months, 72 (29.4%) had HF with reduced LVEF. After baseline electrical cardioversion (ECV), 190 (77.6%) had AF recurrences; 108 (56.8%) received class I/III AADs; 19 (17.6%) flecainide, 36 (33.3%) sotalol, 3 (2.8%) dronedarone, 50 (46.3%) amiodarone. At 1-year 73 of 108 (68.0%) patients were in sinus rhythm, 44 (40.7%) without new AF recurrences. Maintenance of sinus rhythm was significantly better with amiodarone [n = 29/50 (58%)] compared with flecainide [n = 6/19 (32%)] and sotalol/dronedarone [n = 9/39 (23%)], P = 0.0064. Adverse events occurred in 27 (25.0%) patients, were all minor and reversible. Conclusion: In stable HF patients with early persistent AF, AAD treatment was effective in nearly half of patients, with no serious adverse effects reported

    The genetic basis of apparently idiopathic ventricular fibrillation:A retrospective overview

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    Aims: During the diagnostic work-up of patients with idiopathic ventricular fibrillation (VF), next-generation sequencing panels can be considered to identify genotypes associated with arrhythmias. However, consensus for gene panel testing is still lacking, and variants of uncertain significance (VUS) are often identified. The aim of this study was to evaluate genetic testing and its results in idiopathic VF patients. Methods and results: We investigated 419 patients with available medical records from the Dutch Idiopathic VF Registry. Genetic testing was performed in 379 (91%) patients [median age at event 39 years (27-51), 60% male]. Single-gene testing was performed in 87 patients (23%) and was initiated more often in patients with idiopathic VF before 2010. Panel testing was performed in 292 patients (77%). The majority of causal (likely) pathogenic variants (LP/P, n = 56, 15%) entailed the DPP6 risk haplotype (n = 39, 70%). Moreover, 10 LP/P variants were found in cardiomyopathy genes (FLNC, MYL2, MYH7, PLN (two), TTN (four), RBM20), and 7 LP/P variants were identified in genes associated with cardiac arrhythmias (KCNQ1, SCN5A (2), RYR2 (four)). For eight patients (2%), identification of an LP/P variant resulted in a change of diagnosis. In 113 patients (30%), a VUS was identified. Broad panel testing resulted in a higher incidence of VUS in comparison to single-gene testing (38% vs. 3%, P &lt; 0.001). Conclusion: Almost all patients from the registry underwent, albeit not broad, genetic testing. The genetic yield of causal LP/P variants in idiopathic VF patients is 5%, increasing to 15% when including DPP6. In specific cases, the LP/P variant is the underlying diagnosis. A gene panel specifically for idiopathic VF patients is proposed.</p

    The genetic basis of apparently idiopathic ventricular fibrillation:A retrospective overview

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    Aims: During the diagnostic work-up of patients with idiopathic ventricular fibrillation (VF), next-generation sequencing panels can be considered to identify genotypes associated with arrhythmias. However, consensus for gene panel testing is still lacking, and variants of uncertain significance (VUS) are often identified. The aim of this study was to evaluate genetic testing and its results in idiopathic VF patients. Methods and results: We investigated 419 patients with available medical records from the Dutch Idiopathic VF Registry. Genetic testing was performed in 379 (91%) patients [median age at event 39 years (27-51), 60% male]. Single-gene testing was performed in 87 patients (23%) and was initiated more often in patients with idiopathic VF before 2010. Panel testing was performed in 292 patients (77%). The majority of causal (likely) pathogenic variants (LP/P, n = 56, 15%) entailed the DPP6 risk haplotype (n = 39, 70%). Moreover, 10 LP/P variants were found in cardiomyopathy genes (FLNC, MYL2, MYH7, PLN (two), TTN (four), RBM20), and 7 LP/P variants were identified in genes associated with cardiac arrhythmias (KCNQ1, SCN5A (2), RYR2 (four)). For eight patients (2%), identification of an LP/P variant resulted in a change of diagnosis. In 113 patients (30%), a VUS was identified. Broad panel testing resulted in a higher incidence of VUS in comparison to single-gene testing (38% vs. 3%, P &lt; 0.001). Conclusion: Almost all patients from the registry underwent, albeit not broad, genetic testing. The genetic yield of causal LP/P variants in idiopathic VF patients is 5%, increasing to 15% when including DPP6. In specific cases, the LP/P variant is the underlying diagnosis. A gene panel specifically for idiopathic VF patients is proposed.</p
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