Fingerprinting of hydroxyl radical-attacked polysaccharides by N-isopropyl-2-aminoacridone labelling

Hydroxyl radicals ((•)OH) cause non-enzymic scission of polysaccharides in diverse biological systems. Such reactions can be detrimental (e.g. causing rheumatic and arthritic diseases in mammals) or beneficial (e.g. promoting the softening of ripening fruit, and biomass saccharification). Here we present a method for documenting (•)OH action, based on fluorescent labelling of the oxo groups that are introduced as glycosulose residues when (•)OH attacks polysaccharides. The method was tested on several polysaccharides, especially pectin, after treatment with Fenton reagents. 2-Aminoacridone plus cyanoborohydride reductively aminated the oxo groups in treated polysaccharides; the product was then reacted with acetone plus cyanoborohydride, forming a stable tertiary amine with the carbohydrate linked to N-isopropyl-2-aminoacridone (pAMAC). Digestion of labelled pectin with ‘Driselase’ yielded several fluorescent products which on electrophoresis and HPLC provided a useful ‘fingerprint’ indicating (•)OH attack. The most diagnostic product was a disaccharide conjugate of the type pAMAC·UA-GalA (UA=unspecified uronic acid), whose UA-GalA bond was Driselase-resistant (product 2A). 2A was clearly distinguishable from GalA-GalA–pAMAC (disaccharide labelled at its reducing end), which was digestible to GalA–pAMAC. The methodology is applicable, with appropriate enzymes in place of Driselase, for detecting natural and artificial (•)OH attack in diverse plant, animal and microbial polysaccharides

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

798-4 Predictors of the Efficacy of Sotalol, a Class III Antiarrhythmic Agent, in the Treatment of Atrial Arrhythmias

Sotalol, a class III antiarrhythmic drug (AAD) approved for use in ventricular arrhythmias, is being used with increasing frequency for supraventricular arrhythmias (SVA). To determine the efficacy of sotalol in the treatment of SVA and the predictors of sotalol failure or intolerance, 114 pts in whom Sotalol was begun for SVA were reviewed. All pts had atrial fibrillation (109) and/or atrial flutter (32) (AF: paroxysmal in 76, chronic in 35), except for 3 who had SVT. Mean duration after diagnosis of SVA was 5.2±8.2 yrs. The mean number of priorfailed AADs was 1.96±1.27 (range 0–6). Electrical cardioversion was achieved in 38/41 pts; 18 pts pharmacologically converted. Sotalol was stopped prior to discharge in 16 pts (inefficacy in 8, side effects in 4, prolonged QT in 2, and no longer indicated in 2). Prior to discharge, proarrhythmia occurred in 1 pt and bradycardia in 15 pts. 26 pts had prior pacemakers, and 11 pts required pacemakers for sotalol. Mean discharge dose was 229±78mg/day and mean discharge QTc was 462±59ms. Predictors for discontinuation of sotalol prior to discharge included degree of left atrial enlargement (LAE, p=0.03) and QTc on sotalol (p=0.063). Of 88 pts discharged on sotalol in sinus rhythm, 52 developed recurrent SVA (mean f/u 7.8 mos). After dose changes, 3 more pts became recurrence free. Of 36 recurrence-free pts, 12 had sotalol discontinued (side effects in 7, no longer indicated in 5). 2 pts discharged on sotalol developed proarrhythmia, and 2 pts died (1 noncardiac and 1 CVA). Overall, 27/114 pts (23.6%) begun on sotalol remained recurrence free and on the drug. Of 10 pts who began sotalol as first line antiarrhythmic therapy, 2 stopped sotalol in the hospital, 2 after hospital discharge, and 2 recurred after discharge (overall 40% recurrence free on sotalol). Univariate predictors of recurrent SVA on sotalol for pts discharged in NSR included younger age (60±13 vs 68±9 yrs, p=0.001), longer duration since diagnosis of SVA (7.7±11 vs 2.8±4.0 yrs, p=0.009), prior CABG (p=0.01), number of failed AADs (2.4±1.3 vs 1.4±1.1, p=0.0003), and shorter baseline QTc (441±46 vs 465±59 ms, p=0.049) and discharge QRS (109±32 vs 128±41 ms, p=0.025). Changes in HR or QTc were not significant predictors of sotalol success. Significant multivariate predictors of SVA recurrence adjusted for the follow-up period included number of failed AADs (p=0.0024), discharge QRS (p=0.0038) and age (p=0.03). In summary, sotalol showed moderate (24%) efficacy in pts previously refractory to AADs and comparable efficacy as a first-line agent to that reported with other AADs. Changes in QT interval or HR could not be used to predict long term efficacy

Novel robotic catheter remote control system: feasibility and safety of transseptal puncture and endocardial catheter navigation

OBJECTIVES: The aims of this study were to demonstrate the safety and the feasibility of the robotic catheter remote control system (CCS) in endocardial navigation in all cardiac chambers, as well as facilitation of the transseptal puncture. BACKGROUND: CCS has been developed to facilitate control and precise positioning of catheters within the cardiovascular system. METHODS: CCS consists of a remote catheter manipulator, a set up joint, a physician workstation, and a steerable guide catheter (SGC) and sheath. A conventional 4-mm tip catheter was inserted through the SGC to perform mapping of five predefined targets in each cardiac chamber. Seven mongrel dogs were used in this study. Intracardiac echocardiography and three-dimensional (3-D) electroanatomical mapping were integrated with CCS to facilitate catheter manipulation and to guide transseptal puncture. The time to complete the transseptal puncture and the time to complete access to the predefined targets in each cardiac chamber were measured. Gross and microscopic examinations of the accessed and ablation sites were performed to evaluate safety. RESULTS: Transseptal puncture was performed successfully in all animals with a mean time of 7 +/- 3 minutes. Procedure times to access the five targets in the right atrium, right ventricle, left atrium, and left ventricle were 5.6 +/- 1.7, 4.6 +/- 1.5, 13.5 +/- 11.0, 7.0 +/- 2.9 minutes, respectively. There were no intracardiac damages associated with catheter manipulation noted in the excised hearts. CONCLUSIONS: Endocardial catheter navigation and mapping using the robotic catheter remote control is safe and feasible. Moreover, the CCS could be used to perform transseptal puncture and left atrial instrumentation