The Effect of Pectoral Nerve Blocks on Opioid Use and Postoperative Pain in Masculinizing Mastectomy: A Randomized Controlled Trial.

BACKGROUND: Bilateral masculinizing mastectomy is the most common gender-affirmation operation performed. Currently, there is lack of data regarding intraoperative and postoperative pain control for this population. It is the authors' aim to study the effects of the pectoral nerve (Pecs) I and II regional nerve blocks in patients undergoing masculinizing mastectomy. METHODS: A randomized, double-blind, placebo-controlled trial was performed. Patients undergoing bilateral gender-affirmation mastectomy were randomized to receive either a Pecs block with ropivacaine or placebo injection. The patient, surgeon, and anesthesia team were blinded to the allocation. Intraoperative and postoperative opioid requirements were collected and recorded as morphine milligram equivalents (MME). Participants recorded postoperative pain scores at specific time points on the day of surgery through postoperative day 7. RESULTS: Fifty patients were enrolled between July of 2020 and February of 2022. Twenty-seven were randomized to the intervention group and 23 to the control group, with 43 patients undergoing analysis. There was no significant difference in intraoperative MME between the Pecs block group and the control group (9.8 versus 11.1; P = 0.29). In addition, there was no difference in postoperative MME between the groups (37.5 versus 40.0; P = 0.72). Postoperative pain scores were also similar between the groups at each specified time point. CONCLUSIONS: There was no significant reduction in opioid consumption or postoperative pain scores in patients undergoing bilateral gender-affirmation mastectomy who received a regional anesthetic when compared with placebo. In addition, a postoperative opioid-sparing approach may be appropriate for patients undergoing bilateral masculinizing mastectomy. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, I.

Effect of temperature on the degradation of glyphosate by Mn-oxide: Products and pathways of degradation.

Glyphosate is the most commonly used herbicide in the United States. In the environment, glyphosate residues can either degrade into more toxic and persistent byproducts such as aminomethylphosphonic acid (AMPA) or environmentally benign species such as sarcosine or glycine. In this research, the birnessite-catalyzed degradation of glyphosate was studied under environmentally relevant temperatures (10-40 °C) using high-performance liquid chromatography, inductively coupled plasma mass spectrometry, nuclear magnetic resonance, and theoretical calculations. Our results show a temperature-dependent degradation pathway preference for AMPA and glycine production. The AMPA and glycine pathways are competitive at short reaction times, but the glycine pathway became increasingly preferred as reaction time and temperature increased. The measured free energy barriers are comparable for both the glycine and AMPA pathways (93.5 kJ mol-1 for glycine and 97.1 kJ mol-1 for AMPA); however, the entropic energy penalty for the AMPA pathway is significantly greater than the glycine pathway (-TΔS‡ = 26.2 and 42.8 kJ mol-1 for glycine and AMPA, respectively). These findings provide possible routes for biasing glyphosate degradation towards safer products, thus to decrease the overall environmental toxicity.

Symptomatic Intracranial Hemorrhage With Tenecteplase vs Alteplase in Patients With Acute Ischemic Stroke: The Comparative Effectiveness of Routine Tenecteplase vs Alteplase in Acute Ischemic Stroke (CERTAIN) Collaboration.

Importance: Symptomatic intracranial hemorrhage (sICH) is a serious complication of stroke thrombolytic therapy. Many stroke centers have adopted 0.25-mg/kg tenecteplase instead of alteplase for stroke thrombolysis based on evidence from randomized comparisons to alteplase as well as for its practical advantages. There have been no significant differences in symptomatic intracranial hemorrhage (sICH) reported from randomized clinical trials or published case series for the 0.25-mg/Kg dose. Objective: To assess the risk of sICH following ischemic stroke in patients treated with tenecteplase compared to those treated with alteplase. Design, Setting, and Participants: This was a retrospective observational study using data from the large multicenter international Comparative Effectiveness of Routine Tenecteplase vs Alteplase in Acute Ischemic Stroke (CERTAIN) collaboration comprising deidentified data on patients with ischemic stroke treated with intravenous thrombolysis. Data from more than 100 hospitals in New Zealand, Australia, and the US that used alteplase or tenecteplase for patients treated between July 1, 2018, and June 30, 2021, were included for analysis. Participating centers included a mix of nonthrombectomy- and thrombectomy-capacity comprehensive stroke centers. Standardized data were abstracted and harmonized from local or regional clinical registries. Consecutive patients with acute ischemic stroke who were considered eligible and received thrombolysis at the participating stroke registries during the study period were included. All 9238 patients who received thrombolysis were included in this retrospective analysis. Main Outcomes and Measures: sICH was defined as clinical worsening of at least 4 points on the National Institutes of Health Stroke Scale (NIHSS), attributed to parenchymal hematoma, subarachnoid, or intraventricular hemorrhage. Differences between tenecteplase and alteplase in the risk of sICH were assessed using logistic regression, adjusted for age, sex, NIHSS score, and thrombectomy. Results: Of the 9238 patients included in the analysis, the median (IQR) age was 71 (59-80) years, and 4449 patients (48%) were female. Tenecteplase was administered to 1925 patients. The tenecteplase group was older (median [IQR], 73 [61-81] years vs 70 [58-80] years; P < .001), more likely to be male (1034 of 7313 [54%] vs 3755 of 1925 [51%]; P < .01), had higher NIHSS scores (median [IQR], 9 [5-17] vs 7 [4-14]; P < .001), and more frequently underwent endovascular thrombectomy (38% vs 20%; P < .001). The proportion of patients with sICH was 1.8% for tenecteplase and 3.6% for alteplase (P < .001), with an adjusted odds ratio (aOR) of 0.42 (95% CI, 0.30-0.58; P < .01). Similar results were observed in both thrombectomy and nonthrombectomy subgroups. Conclusions and Relevance: In this large study, ischemic stroke treatment with 0.25-mg/kg tenecteplase was associated with lower odds of sICH than treatment with alteplase. The results provide evidence supporting the safety of tenecteplase for stroke thrombolysis in real-world clinical practice.

The role of iron in the formation of Ediacaran 'death masks'.

The Ediacara biota are an enigmatic group of Neoproterozoic soft-bodied fossils that mark the first major radiation of complex eukaryotic and macroscopic life. These fossils are thought to have been preserved via pyritic "death masks" mediated by seafloor microbial mats, though little about the chemical constraints of this preservational pathway is known, in particular surrounding the role of bioavailable iron in death mask formation and preservational fidelity. In this study, we perform decay experiments on both diploblastic and triploblastic animals under a range of simulated sedimentary iron concentrations, in order to characterize the role of iron in the preservation of Ediacaran organisms. After 28 days of decay, we demonstrate the first convincing "death masks" produced under experimental laboratory conditions composed of iron sulfide and probable oxide veneers. Moreover, our results demonstrate that the abundance of iron in experiments is not the sole control on death mask formation, but also tissue histology and the availability of nucleation sites. This illustrates that Ediacaran preservation via microbial death masks need not be a "perfect storm" of paleoenvironmental porewater and sediment chemistry, but instead can occur under a range of conditions.

Trial of Endovascular Thrombectomy for Large Ischemic Strokes.

BACKGROUND: Trials of the efficacy and safety of endovascular thrombectomy in patients with large ischemic strokes have been carried out in limited populations. METHODS: We performed a prospective, randomized, open-label, adaptive, international trial involving patients with stroke due to occlusion of the internal carotid artery or the first segment of the middle cerebral artery to assess endovascular thrombectomy within 24 hours after onset. Patients had a large ischemic-core volume, defined as an Alberta Stroke Program Early Computed Tomography Score of 3 to 5 (range, 0 to 10, with lower scores indicating larger infarction) or a core volume of at least 50 ml on computed tomography perfusion or diffusion-weighted magnetic resonance imaging. Patients were assigned in a 1:1 ratio to endovascular thrombectomy plus medical care or to medical care alone. The primary outcome was the modified Rankin scale score at 90 days (range, 0 to 6, with higher scores indicating greater disability). Functional independence was a secondary outcome. RESULTS: The trial was stopped early for efficacy; 178 patients had been assigned to the thrombectomy group and 174 to the medical-care group. The generalized odds ratio for a shift in the distribution of modified Rankin scale scores toward better outcomes in favor of thrombectomy was 1.51 (95% confidence interval [CI], 1.20 to 1.89; P<0.001). A total of 20% of the patients in the thrombectomy group and 7% in the medical-care group had functional independence (relative risk, 2.97; 95% CI, 1.60 to 5.51). Mortality was similar in the two groups. In the thrombectomy group, arterial access-site complications occurred in 5 patients, dissection in 10, cerebral-vessel perforation in 7, and transient vasospasm in 11. Symptomatic intracranial hemorrhage occurred in 1 patient in the thrombectomy group and in 2 in the medical-care group. CONCLUSIONS: Among patients with large ischemic strokes, endovascular thrombectomy resulted in better functional outcomes than medical care but was associated with vascular complications. Cerebral hemorrhages were infrequent in both groups. (Funded by Stryker Neurovascular; SELECT2 ClinicalTrials.gov number, NCT03876457.).

Safety of Incision Placement with Nipple-sparing Mastectomy and Immediate Prepectoral Breast Reconstruction.

In nipple-sparing mastectomy, adequate perfusion to the nipple-areolar complex (NAC) during reconstruction is paramount to avoiding unwanted outcomes. Previous studies have suggested that periareolar incisions may result in higher rates of NAC complications. However, studies to date have not specifically investigated this in prepectoral reconstruction. The purpose of this study is to evaluate the impact of incision location on NAC complications in patients undergoing prepectoral breast reconstruction. Methods: We performed a retrospective review of all patients who underwent immediate two-stage prepectoral breast reconstruction following nipple-sparing mastectomy between 2015 and 2018 at a single institution. We identified two types of incisions utilized: superior periareolar or inframammary fold (IMF). Patient demographics, comorbidities, and surgical details were compared between incision types, as were NAC complications. Results: A total of 181 consecutive prepectoral breast reconstructions were included for analysis. A superior periareolar incision was used in 113 reconstructions (62%), and an IMF incision was used in 68 reconstructions (38%). There were 33 (18%) total NAC complications in our series. The periareolar incision group had a higher rate of any NAC complication (25% versus 7.4%; P < 0.01), as well as a higher rate of nipple necrosis requiring debridement (9.7% versus 1.5%; P = 0.03). Conclusions: In patients undergoing immediate two-stage prepectoral breast reconstruction following nipple-sparing mastectomy, periareolar incisions are associated with an increased risk of NAC complications compared with IMF incisions. For patients who are candidates for either an IMF or periareolar incision, a periareolar incision should be avoided.

The effects of palladium coordination complex speciation and concentration upon the ubiquitous bacterial species Pseudomonas aeruginosa.

The toxicity of three different palladium (Pd) species to Pseudomonas aeruginosa, an environmentally ubiquitous bacterial species, is reported. Palladium was added to chemically-defined minimal media as three complex ion salts, namely sodium tetrachloropalladate (Na2[PdCl4]), tetraamminepalladium(II) chloride ([Pd(NH3)4]Cl2), and potassium hexachloropalladate(IV) (K2[PdCl6]), inoculated with log-phase cultures and incubated for 24 h at 25 °C. Toxicity was tested for Pd concentrations ranging from 6.55 µg/L (0.06 µM Pd) to 250 µg/L (2.33 µM Pd). Minimum inhibitory concentrations (MICs) were determined and growth tracked via optical absorption at 600 nm. Viability and minimum bactericidal concentrations (MBCs) were measured in parallel with dilution, plating and colony forming unit (CFU) counting. MICs for all forms of Pd were 62.5 µg Pd/L, approximately 1000 times lower than previously reported values. The MBCs for PdCl42- and Pd(NH3)42+ were 62.5 µg Pd/L and 125 µg Pd/L for PdCl62-. Pd(NH3)42+ and PdCl62- culture viability at 7.8-31.3 µg Pd/L was not different from controls. However, PdCl42- culture viability was different from the other additives, with decreasing viability at sub-MBC concentrations down to 6.55 µg Pd/L. To understand the possible effect of speciation upon toxicity, the equilibrium speciation of Pd was modeled for all solutions using PHREEQC and found to be dominated by Pd(NH3)3Cl+ (65.6 % of total Pd) and Pd(NH3)42+ (34.2 % total Pd). The juxtaposition of the equilibrium calculations and the toxicity results indicates that the kinetics of ligand exchange between the palladium complexes and the growth medium could influence bacterial response.

Association of Endovascular Thrombectomy vs Medical Management With Functional and Safety Outcomes in Patients Treated Beyond 24 Hours of Last Known Well: The SELECT Late Study.

Importance: The role of endovascular thrombectomy is uncertain for patients presenting beyond 24 hours of the time they were last known well. Objective: To evaluate functional and safety outcomes for endovascular thrombectomy (EVT) vs medical management in patients with large-vessel occlusion beyond 24 hours of last known well. Design, Setting, and Participants: This retrospective observational cohort study enrolled patients between July 2012 and December 2021 at 17 centers across the United States, Spain, Australia, and New Zealand. Eligible patients had occlusions in the internal carotid artery or middle cerebral artery (M1 or M2 segment) and were treated with EVT or medical management beyond 24 hours of last known well. Interventions: Endovascular thrombectomy or medical management (control). Main Outcomes and Measures: Primary outcome was functional independence (modified Rankin Scale score 0-2). Mortality and symptomatic intracranial hemorrhage (sICH) were safety outcomes. Propensity score (PS)-weighted multivariable logistic regression analyses were adjusted for prespecified clinical characteristics, perfusion parameters, and/or Alberta Stroke Program Early CT Score (ASPECTS) and were repeated in subsequent 1:1 PS-matched cohorts. Results: Of 301 patients (median [IQR] age, 69 years [59-81]; 149 female), 185 patients (61%) received EVT and 116 (39%) received medical management. In adjusted analyses, EVT was associated with better functional independence (38% vs control, 10%; inverse probability treatment weighting adjusted odds ratio [IPTW aOR], 4.56; 95% CI, 2.28-9.09; P < .001) despite increased odds of sICH (10.1% for EVT vs 1.7% for control; IPTW aOR, 10.65; 95% CI, 2.19-51.69; P = .003). This association persisted after PS-based matching on (1) clinical characteristics and ASPECTS (EVT, 35%, vs control, 19%; aOR, 3.14; 95% CI, 1.02-9.72; P = .047); (2) clinical characteristics and perfusion parameters (EVT, 35%, vs control, 17%; aOR, 4.17; 95% CI, 1.15-15.17; P = .03); and (3) clinical characteristics, ASPECTS, and perfusion parameters (EVT, 45%, vs control, 21%; aOR, 4.39; 95% CI, 1.04-18.53; P = .04). Patients receiving EVT had lower odds of mortality (26%) compared with those in the control group (41%; IPTW aOR, 0.49; 95% CI, 0.27-0.89; P = .02). Conclusions and Relevance: In this study of treatment beyond 24 hours of last known well, EVT was associated with higher odds of functional independence compared with medical management, with consistent results obtained in PS-matched subpopulations and patients with presence of mismatch, despite increased odds of sICH. Our findings support EVT feasibility in selected patients beyond 24 hours. Prospective studies are warranted for confirmation.

Thrombectomy versus Medical Management in Mild Strokes due to Large Vessel Occlusion: Exploratory Analysis from the EXTEND-IA Trials and a Pooled International Cohort.

OBJECTIVE: This study was undertaken to evaluate functional and safety outcomes for endovascular thrombectomy (EVT) versus medical management (MM) in patients with large vessel occlusion (LVO) and mild neurological deficits, stratified by perfusion imaging mismatch. METHODS: The pooled cohort consisted of patients with National Institutes of Health Stroke Scale (NIHSS) < 6 and internal carotid artery (ICA), M1, or M2 occlusions from the Extending the Time for Thrombolysis in Emergecy Neurological Deficits - Intra-Arterial (EXTEND-IA) Trial,  Tenecteplase vs Alteplase before Endovascular Thrombectomy in Ischemic Stroke (EXTEND-IA TNK) trials Part I/II and prospective data from 15 EVT centers from October 2010 to April 2020. RAPID software estimated ischemic core and mismatch. Patients receiving primary EVT (EVTpri ) were compared to those who received primary MM (MMpri ), including those who deteriorated and received rescue EVT, in overall and propensity score (PS)-matched cohorts. Patients were stratified by target mismatch (mismatch ratio ≥ 1.8 and mismatch volume ≥ 15ml). Primary outcome was functional independence (90-day modified Rankin Scale = 0-2). Secondary outcomes included safety (symptomatic intracerebral hemorrhage [sICH], neurological worsening, and mortality). RESULTS: Of 540 patients, 286 (53%) received EVTpri and demonstrated larger critically hypoperfused tissue (Tmax > 6 seconds) volumes (median [IQR]: 64 [26-96] ml vs MMpri : 40 [14-76] ml, p < 0.001) and higher presentation NIHSS (median [IQR]: 4 [2-5] vs MMpri : 3 [2-4], p < 0.001). Functional independence was similar (EVTpri : 77.4% vs MMpri : 75.6%, adjusted odds ratio [aOR] = 1.29, 95% confidence interval [CI] = 0.82-2.03, p = 0.27). EVT had worse safety regarding sICH (EVTpri : 16.3% vs MMpri : 1.3%, p < 0.001) and neurological worsening (EVTpri : 19.6% vs MMpri : 6.7%, p < 0.001). In 414 subjects (76.7%) with target mismatch, EVT was associated with improved functional independence (EVTpri : 77.4% vs MMpri : 72.7%, aOR = 1.68, 95% CI = 1.01-2.81, p = 0.048), whereas there was a trend toward less favorable outcomes with primary EVT (EVTpri : 77.4% vs MMpri : 83.3%, aOR = 0.39, 95% CI = 0.12-1.34, p = 0.13) without target mismatch (pinteraction  = 0.06). Similar findings were observed in a propensity score-matched subpopulation. INTERPRETATION: Overall, EVT was not associated with improved clinical outcomes in mild strokes due to LVO, and sICH was increased. However, in patients with target mismatch profile, EVT was associated with increased functional independence. Perfusion imaging may be helpful to select mild stroke patients for EVT. ANN NEUROL 2022;92:364-378.

Racial Disparity in Mechanical Thrombectomy Utilization: Multicenter Registry Results From 2016 to 2020.

Background Previous studies on racial disparity in mechanical thrombectomy (MT) treatment of acute large vessel occlusion stroke lack individual patient data that influence treatment decision-making. We assessed patient-level data in a large US health care system from 2016 to 2020 for racial disparities in MT utilization and eligibility. Methods and Results A retrospective study was performed of 34 596 patients admitted to 43 hospitals from January 2016 to September 2020. Data included patient age, sex, race, residential zip code median income and population density, presenting hospital stroke certification, baseline ambulation, and National Institutes of Health stroke scale. The cohort included 26 640 White, non-Hispanic (77.0%), and 7956 African American/Black (23.0%) patients. In multivariable logistic regression, Black patients were less likely to undergo MT (adjusted odds ratio [OR], 0.65; 95% CI, 0.54-0.76), arrive within 5 hours of "last known well" (adjusted OR, 0.73; 95% CI, 0.69-0.78), and have documented anterior circulation large vessel occlusion (adjusted OR, 0.78; 95% CI, 0.64-0.96). Race was not associated with MT rate among patients arriving within 5 hours of last known well with documented acute large vessel occlusion. Conclusions Black patients with stroke underwent MT less frequently than White patients, likely in part because of longer times from last known well to hospital arrival and a lower rate of documented acute large vessel occlusion. Further studies are needed to assess whether extending the MT time window and more aggressive large vessel occlusion screening protocols mitigate this disparity.

Diagnosis and Treatment of Lymphatic Complications of the Groin Following Open Lower Extremity Revascularization with Plastic Surgery Closure.

INTRODUCTION: Lymphatic complications following vascular procedures involving the groin require prompt treatment to limit morbidity. Several treatments have been described, including conservative management, aspiration, sclerotherapy, and direct lymphatic ligation with or without a muscle flap have been described. To date, there is no data indicating which treatment results in the shortest time to recovery. We sought to address this gap by conducting a retrospective cohort study. METHODS: We reviewed all patients who developed a lymphatic complication after undergoing an open revascularization procedure in the groin between 2014 and 2020 in which plastic surgery was involved in the closure. A control group consisted of patients from the same timespan who did not develop a lymphatic complication. Demographics, comorbidities, operative details, and outcomes were compared between these groups. For cases identified with a lymphatic complication, the method of diagnosis, culture data, and treatment details were collected, and outcomes were compared for surgical management versus sclerotherapy. RESULTS: There were 27 lymphatic complications and 60 control patients. The complication group had a higher incidence of aortofemoral bypass (25.8% vs. 8.3%, P = 0.04), and a lower incidence of femoral-to-distal bypass (11.1% vs. 45.0%, P < 0.01). Daily drain output volume from postoperative days 1-5, and days 6-10, was significantly higher in the complication group than in the controls (194.0 vs. 44.0, P < 0.01; and 429.5 vs. 35.0, P < 0.01, respectively). In the lymphatic leak group, 16 patients (59.3%) had surgical treatment and six (22.2%) had sclerotherapy. Of those who had surgery, 71.4% had successful outcomes without the need for an additional intervention, whereas all of the patients analyzed who were treated with sclerotherapy had successful outcomes without further intervention. The average time to resolution was significantly shorter for surgery than for sclerotherapy (38.7 vs. 86.0 days, P = 0.03). CONCLUSIONS: Daily postoperative drain volume can assist with early diagnosis of a lymphatic leak in the groin following an open revascularization procedure. Sclerotherapy and surgery were each successful, but surgery resulted in significantly shorter times to resolution. In the appropriate candidates, surgery should be considered first line management of a lymphatic leak.

Prophylactic Muscle Flaps in Primary Vascular Procedures of the Groin.

BACKGROUND: Complications following vascular procedures involving the groin can lead to significant morbidity. Achieving stable soft tissue coverage over sites of revascularization can help mitigate complications. Prior evidence supports the use of muscle flaps in reoperative groins and in high risk patient populations to reduce postoperative complications. Data regarding the use of prophylactic muscle flap coverage of the groin is lacking. Therefore, the purpose of this study is to evaluate the effect of immediate prophylactic muscle flap coverage of vascular wounds involving the groin. METHODS: A retrospective cohort study was performed on all patients undergoing primary open vascular procedures involving the groin for occlusive, aneurysmal, or oncologic disease between 2014 and 2020 at a single institution where plastic surgery was involved in closure. Patient demographics, comorbidities, surgical details, and postoperative complications were compared between patients who had sartorius muscle flap coverage of the vascular repair versus layered closure alone. RESULTS: A total of 133 consecutive groins were included in our analysis. A sartorius flap was used in 115 groins (86.5%) and a layered closure was used in 18 (13.5%). Wound breakdown was similar between groups (25.2% sartorius vs. 38.9% layered closure, P = 0.26). However, the rate of reoperation was significantly higher in the layered closure group (50.0% vs. 12.2%, P < 0.01). Among patients who experienced wound breakdown (N = 36), a larger proportion of layered closure patients required operative intervention (71.4% vs. 20.7%, P = 0.02). Other rates of complications were not statistically different between groups. CONCLUSIONS: In patients undergoing primary open vascular procedures involving the groin, patients who underwent prophylactic sartorius muscle flap closure had lower rates of reoperation. Although incisional breakdown was similar between the groups overall, the presence of a vascularized muscle flap overlying the vascular repair was associated with reduced need for reoperation and allowed more wounds to be managed with local wound care alone. Consideration should be given to this low morbidity local muscle flap in patients undergoing vascular procedures involving the groin.

Effect of Intravenous Thrombolysis on Clot Survival during Mechanical Thrombectomy in Acute Large Vessel Occlusion Strokes.

BACKGROUND: The benefit of intravenous thrombolysis (IVT) before mechanical thrombectomy (MT) in patients with large vessel occlusion (LVO) stroke is uncertain. Conventional metrics of final modified thrombolysis in cerebral ischemia (mTICI) score and 90-d modified Rankin Scale may be insensitive to IVT effects on procedural complexity and duration. OBJECTIVE: To study the effect of IVT prior to MT on clot survival. METHODS: We performed a single-center retrospective analysis of 257 acute stroke patients with LVO undergoing MT and analyzed the effect of IVT prior to MT using a novel, pass-by-pass clot survival methodology. RESULTS: The use of IVT was associated with a significantly lower number of passes to attain mTICI 2B or greater (P = .002) or mTICI 3 (P = .039) reperfusion. The number of patients who achieved mTICI 2B or greater after the first pass was significantly higher in the IVT group (P = .003). This increased rate of reperfusion persisted into subsequent passes. CONCLUSION: IVT prior to MT reduces the number of thrombectomy passes required to achieve mTICI 2B or mTICI 3 reperfusion. This information should be considered as the merits of IVT prior to MT are debated.

Position-specific isotope effects during alkaline hydrolysis of 2,4-dinitroanisole resolved by compound-specific isotope analysis, 13C NMR, and density-functional theory.

Compound-specific isotope analysis (CSIA), position-specific isotope analysis (PSIA), and computational modeling (e.g., quantum mechanical models; reactive-transport models) are increasingly being used to monitor and predict biotic and abiotic transformations of organic contaminants in the field. However, identifying the isotope effect(s) associated with a specific transformation remains challenging in many cases. Here, we describe and interpret the position-specific isotope effects of C and N associated with a SN2Ar reaction mechanism by a combination of CSIA and PSIA using quantitative 13C nuclear magnetic resonance spectrometry, and density-functional theory, using 2,4-dinitroanisole (DNAN) as a model compound. The position-specific 13C enrichment factor of O-C1 bond at the methoxy group attachment site (εC1) was found to be approximately -41‰, a diagnostic value for transformation of DNAN to its reaction products 2,4-dinitrophenol and methanol. Theoretical kinetic isotope effects calculated for DNAN isotopologues agreed well with the position-specific isotope effects measured by CSIA and PSIA. This combination of measurements and theoretical predictions demonstrates a useful tool for evaluating degradation efficiencies and/or mechanisms of organic contaminants and may promote new and improved applications of isotope analysis in laboratory and field investigations.

Patient Characteristics and Outcomes Associated with Decline in Stroke Volumes During the Early COVID-19 Pandemic.

BACKGROUND AND PURPOSE: Delayed evaluation of stroke may contribute to COVID-19 pandemic-related morbidity and mortality. This study evaluated patient characteristics, process measures and outcomes associated with the decline in stroke presentation during the early pandemic. METHODS: Volumes of stroke presentations, intravenous thrombolytic administrations, and mechanical thrombectomies from 52 hospitals from January 1-June 30, 2020 were analyzed with piecewise linear regression and linear spline models. Univariate analysis compared pandemic (case) and pre-pandemic (control) groups defined in relation to the nadir of daily strokes during the study period. Significantly different patient characteristics were further evaluated with logistic regression, and significantly different process measures and outcomes were re-analyzed after propensity score matching. RESULTS: Analysis of 7,389 patients found daily stroke volumes decreased 0.91/day from March 12-26 (p < 0.0001), reaching a nadir 35.0% less than expected, and increased 0.15 strokes/day from March 27-June 23, 2020 (p < 0.0001). Intravenous thrombolytic administrations decreased 3.3/week from February 19-March 31 (p = 0.0023), reaching a nadir 33.4% less than expected, and increased 1.4 administrations/week from April 1-June 23 (p < 0.0001). Mechanical thrombectomy volumes decreased by 1.5/week from February 19-March 31, 2020 (p = 0.0039), reaching a nadir 11.3% less than expected. The pandemic group was more likely to ambulate independently at baseline (p = 0.02, OR = 1.60, 95% CI = 1.08-2.42), and less likely to present with mild stroke symptoms (NIH Stroke Scale ≤ 5; p = 0.04, OR = 1.01, 95% CI = 1.00-1.02). Process measures and outcomes of each group did not differ, including door-to-needle time, door-to-puncture time, and successful mechanical thrombectomy rate. CONCLUSION: Stroke presentations and acute interventions decreased during the early COVID-19 pandemic, at least in part due to patients with lower baseline functional status and milder symptoms not seeking medical care. Public health messaging and initiatives should target these populations.

Diradical Interactions in Ring-Open Isoxazole.

Electron capture by the σ* LUMO of isoxazole triggers the dissociation of the O-N bond and the opening of the ring. Photodetachment of the resulting anion accesses a neutral structure, in which the O· and ·N bond fragments interact through the intact remainder of the molecular ring and via a 3 Å gap created by the bond dissociation. These through-bond and through-space interactions result in a dense manifold of diradical states, including (in the order of increasing energy) a triplet, an open-shell singlet, a closed-shell singlet, and another triplet state. We report photoelectron spectra that reflect partially resolved signatures of these states. Remarkably, the structure of the isoxazole diradical manifold is qualitatively different from that of the analogous system in oxazole. The distinct properties of the two manifolds are explained by using a coupled-fragments molecular-orbital model. Consistent with the past conclusions [Culberson et al. Phys. Chem. Chem. Phys. 2014, 16, 3964-3972], the lingering through-space interactions between the O· and ·C bond fragments in ring-open oxazole are responsible for the relative stabilization of the closed-shell singlet state, which correlates with the ground-state cyclic structure. In contrast, the placement of the N atom in the terminal position within the ring-open structure of isoxazole is the key factor leading to the near degeneracy of the π and σ* orbitals, favoring a triplet-state configuration.

Evaluation of the Metastatic Spine Disease Multidisciplinary Working Group Algorithms as Part of a Multidisciplinary Spine Tumor Conference.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The Metastatic Spine Disease Multidisciplinary Working Group Algorithms are evidence and expert opinion-based strategies for utilizing radiation therapy, interventional radiology procedures, and surgery to treat 5 types of spine metastases: asymptomatic spinal metastases, uncomplicated spinal metastases, stable vertebral compression fractures (VCF), unstable VCF, and metastatic epidural spinal cord compression (MESCC). Evaluation of this set of algorithms in a clinical setting is lacking. The authors aimed to identify rate of treatment adherence to the Working Group Algorithms and, subsequently, update these algorithms based on actual patient management decisions made at a single-institution, multidisciplinary, spine tumor conference. METHODS: Patients with metastatic spine disease from primary non-hematologic malignancies discussed at an institutional spine tumor conference from 2013 to 2016 were evaluated. Rates of Working Group Algorithms adherence were calculated for each type of metastasis. Based on the reasons for algorithm nonadherence, and patient outcomes in such cases, updated Working Group Algorithms recommendations were proposed. RESULTS: In total, 154 eligible patients with 171 spine metastases were evaluated. Rates of algorithm adherence were as follows: asymptomatic (67%), uncomplicated (73%), stable VCF (20%), unstable VCF (32%), and MESCC (41%). The most common deviation from the Working Group Algorithms was surgery for MESCC despite poor prognostic factors, but this treatment strategy was supported based on median survival surpassing 6 months in these patients. CONCLUSIONS: Adherence to the Working Group Algorithm was lowest for MESCC and VCF patients, but many nonadherent treatments were supported by patient survival outcomes. We proposed updates to the Working Group Algorithm based on these findings.

Deprotonation of Isoxazole: A Photoelectron Imaging Study.

We report a photoelectron imaging study of gas-phase deprotonation of isoxazole in which spectroscopic data are compared to the results of electronic structure calculations for the anion products corresponding to each of three possible deprotonation sites. The observed photoelectron spectra are assigned to a mixture of the anion isomers. Deprotonation at the most acidic (C5) and the least acidic (C4) positions yields the respective C5- and C4-isoxazolide anions, while the reaction at the intermediate-acidity C3 site leads to a cleavage of the O-N bond and an opening of the ring in the anion. Following photodetachment, the ground states of neutral C5- and C4-isoxazolyl are assigned to be σ radicals (X2A'), while the ground-state neutral derived from the ring-open C3-anion is a π radical (X2A″). The relative intensities of the spectral bands exhibit sensitivity to the ion source conditions, giving evidence of competing and varying contributions of the dominant C5 and C3, as well as possible C4, deprotonation pathways.

Dual antiplatelet therapy does not improve outcomes after aneurysmal subarachnoid hemorrhage compared with aspirin monotherapy.

BACKGROUND: The pathophysiology of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) may include platelet activation and microthrombi formation. Antiplatelet therapy may reduce the incidence of DCI and improve clinical outcomes after aSAH. This study compared outcomes among aSAH patients receiving aspirin monotherapy versus dual antiplatelet therapy (DAPT). METHODS: Aneurysmal subarachnoid hemorrhage patients treated at a single institution between November 2011 and December 2017 were divided according to whether they received aspirin monotherapy or DAPT after endovascular treatment. Baseline characteristics and outcomes of the groups were compared, including incidences of delayed cerebral ischemia, bleeding complications, symptomatic vasospasm, in-hospital mortality, and functional status 6 months after discharge. RESULTS: During the study period, 142 patients met study inclusion criteria, of which 123 were treated with aspirin monotherapy (87 %) and 19 were treated with DAPT (13 %). There was no statistically significant difference between the aspirin monotherapy and DAPT groups with respect to incidences of delayed cerebral ischemia (4.9 vs 10.5 %; p = 0.32), symptomatic vasospasm (13.0 vs 15.8 %; p = 0.74), or good clinical outcome at 6-month follow up (73.3 vs 66.7 %; p = 0.56). The DAPT group experienced a higher incidence of in-hospital mortality (21 vs 5.7 %; p = 0.02), but DAPT did not remain independently predictive of this outcome on regression analysis. There was a trend toward a higher bleeding complication rate in the DAPT group (0.8 vs 5.3 %; p = 0.13). CONCLUSIONS: DAPT does not reduce the incidence of DCI or improve outcomes in aSAH patients, and may increase the risk of clinically significant bleeding complications.

Interventional Management of Head and Neck Tumors.

Advancements in medical imaging and device technology allow minimal invasive procedures for the diagnosis and treatment of various disorders. For the management of tumors in head and neck region, these image-guided interventions play essential role in the often used multidisciplinary approach. Tissue sampling under ultrasound or computed tomography guidance is generally the first step to reach a pathological diagnosis. For head and neck tumors with high vascularity, embolization using particulate matter, liquid embolic agents, or coils is used to achieve successful tumor resection with minimal blood loss. Hemorrhage related to head and neck tumors can be evaluated and managed with endovascular techniques with minimal morbidity and mortality. Intra-arterial chemotherapy, radiofrequency ablation, and cryotherapy are new techniques for the management of advanced head and neck cancer which may serve as an alternative to achieve locoregional control and survival when curative resection may not be feasible.