A pilot oral history of plant synthetic biology.

The whole field of synthetic biology (SynBio) is only about 20 years old, and plant SynBio is younger still. Nevertheless, within that short time, SynBio in general has drawn more scientific, philosophical, government, and private-sector interest than anything in biology since the recombinant DNA revolution. Plant SynBio, in particular, is now drawing more and more interest in relation to plants' potential to help solve planetary problems such as carbon capture and storage and replacing fossil fuels and feedstocks. As plant SynBio is so young and so fast-developing, we felt it was too soon to try to analyze its history. Instead, we set out to capture the essence of plant SynBio's origins and early development through interviews with 8 of the field's founders, representing 5 countries and 3 continents. We then distilled these founders' personal recollections and reflections into this review, centering the narrative on timelines for pivotal events, articles, funding programs, and quoting from interviews. We have archived the interview recordings and documented timeline entries. This work provides a resource for future historical scholarship.

Clinical presentation and outcomes in patients with antiphospholipid syndrome-associated adrenal hemorrhage. A multicenter cohort study and systematic literature review.

BACKGROUND: Adrenal hemorrhage (AH) can occur in patients with antiphospholipid Syndrome (APS). We aimed to characterize the clinical manifestations, treatments, and outcomes of patients presenting with APS-associated AH (APS-AH) through a retrospective cohort and a systematic literature review (SLR). METHODS: We performed a mixed-source approach combining a multicenter cohort with an SLR of patients with incident APS-AH. We included patients from Mayo Clinic and published cases with persistent positivity for antiphospholipid antibodies and presenting with AH, demonstrated by imaging or biopsy. We extracted demographics, clinical characteristics, laboratory findings, treatment strategies, and outcomes (primary adrenal insufficiency and mortality). We used Kaplan-Meier and Cox models for survival analysis. RESULTS: We included 256 patients in total, 61 (24%) from Mayo Clinic and 195 (76%) from the SLR. The mean age was 46.8 (SD 15.2) years, and 45% were female. 69% of patients had bilateral adrenal involvement and 64% presented adrenal insufficiency. The most common symptoms at presentation were abdominal pain in 79%, and nausea and vomiting 46%. Hyponatremia (77%) was the most common electrolyte abnormality. Factors associated with primary adrenal insufficiency were bilateral adrenal involvement at initial imaging (OR 3.73, CI; 95%, 1.47-9.46) and anticardiolipin IgG positivity (OR 3.80, CI; 95%, 1.30-11.09). The survival rate at five years was 82%. History of stroke was associated with 3.6-fold increase in mortality (HR 3.62, 95% CI; 1.33-9.85). CONCLUSION: AH is a severe manifestation of APS with increased mortality. Most patients developed permanent primary adrenal insufficiency, particularly those positive for anticardiolipin IgG and bilateral adrenal involvement.

Preoperative Anemia and Postoperative Outcomes in Cardiac Surgery: A Mediation Analysis Evaluating Intraoperative Transfusion Exposures.

BACKGROUND: Preoperative anemia is associated with adverse outcomes in cardiac surgery, yet it remains unclear what proportion of this association is mediated through red blood cell (RBC) transfusions. METHODS: This is a historical observational cohort study of adults undergoing coronary artery bypass grafting or valve surgery on cardiopulmonary bypass at an academic medical center between May 1, 2008, and May 1, 2018. A mediation analysis framework was used to evaluate the associations between preoperative anemia and postoperative outcomes, including a primary outcome of acute kidney injury (AKI). Intraoperative RBC transfusions were evaluated as mediators of preoperative anemia and outcome relationships. The estimated total effect, average direct effect of preoperative anemia, and percent of the total effect mediated through transfusions are presented with 95% confidence intervals and P -values. RESULTS: A total of 4117 patients were included, including 1234 (30%) with preoperative anemia. Overall, 437 of 4117 (11%) patients went on to develop AKI, with a greater proportion of patients having preoperative anemia (219 of 1234 [18%] vs 218 of 2883 [8%]). In multivariable analyses, the presence of preoperative anemia was associated with increased postoperative AKI (6.4% [4.2%-8.7%] absolute difference in percent with AKI, P < .001), with incremental decreases in preoperative hemoglobin concentrations displaying greater AKI risk (eg, 11.9% [6.9%-17.5%] absolute increase in probability of AKI for preoperative hemoglobin of 9 g/dL compared to a reference of 14 g/dL, P < .001). The association between preoperative anemia and postoperative AKI was primarily due to direct effects of preoperative anemia (5.9% [3.6%-8.3%] absolute difference, P < .001) rather than mediated through intraoperative RBC transfusions (7.5% [-4.3% to 21.1%] of the total effect mediated by transfusions, P = .220). Preoperative anemia was also associated with longer hospital durations (1.07 [1.05-1.10] ratio of geometric mean length of stay, P < .001). Of this total effect, 38% (22%, 62%; P < .001) was estimated to be mediated through subsequent intraoperative RBC transfusion. Preoperative anemia was not associated with reoperation or vascular complications. CONCLUSIONS: Preoperative anemia was associated with higher odds of AKI and longer hospitalizations in cardiac surgery. The attributable effects of anemia and transfusion on postoperative complications are likely to differ across outcomes. Future studies are necessary to further evaluate mechanisms of anemia-associated postoperative organ injury and treatment strategies.

The number of catalytic cycles in an enzyme's lifetime and why it matters to metabolic engineering.

Metabolic engineering uses enzymes as parts to build biosystems for specified tasks. Although a part's working life and failure modes are key engineering performance indicators, this is not yet so in metabolic engineering because it is not known how long enzymes remain functional in vivo or whether cumulative deterioration (wear-out), sudden random failure, or other causes drive replacement. Consequently, enzymes cannot be engineered to extend life and cut the high energy costs of replacement. Guided by catalyst engineering, we adopted catalytic cycles until replacement (CCR) as a metric for enzyme functional life span in vivo. CCR is the number of catalytic cycles that an enzyme mediates in vivo before failure or replacement, i.e., metabolic flux rate/protein turnover rate. We used estimated fluxes and measured protein turnover rates to calculate CCRs for ∼100-200 enzymes each from Lactococcus lactis, yeast, and Arabidopsis CCRs in these organisms had similar ranges (<103 to >107) but different median values (3-4 × 104 in L. lactis and yeast versus 4 × 105 in Arabidopsis). In all organisms, enzymes whose substrates, products, or mechanisms can attack reactive amino acid residues had significantly lower median CCR values than other enzymes. Taken with literature on mechanism-based inactivation, the latter finding supports the proposal that 1) random active-site damage by reaction chemistry is an important cause of enzyme failure, and 2) reactive noncatalytic residues in the active-site region are likely contributors to damage susceptibility. Enzyme engineering to raise CCRs and lower replacement costs may thus be both beneficial and feasible.

Clinical features, risk factors, and outcomes of diffuse alveolar hemorrhage in antiphospholipid syndrome: A mixed-method approach combining a multicenter cohort with a systematic literature review.

BACKGROUND: Antiphospholipid syndrome (APS) is a systemic autoimmune disease clinically associated with thrombotic and obstetric events. Additional manifestations have been associated with APS, like diffuse alveolar hemorrhage (DAH). We aimed to summarize all the evidence available to describe the presenting clinical features, their prognostic factors, and short- and long-term outcomes. METHODS: We performed a mixed-method approach combining a multicenter cohort with a systematic literature review (SLR) of patients with incident APS-associated DAH. We described their clinical features, treatments, prognostic factors, and outcomes (relapse, mortality, and requirement of mechanical ventilation [MV]). Kaplan-Meier methods were used to estimate relapse and mortality rates, and Cox and logistic regression models were used to assess the factors associated as appropriate. RESULTS: We included 219 patients with incident APS-associated DAH (61 from Mayo Clinic and 158 from SLR). The median age was 39.5 years, 51% were female, 29% had systemic lupus erythematosus, and 34% presented with catastrophic APS (CAPS). 74% of patients had a history of thrombotic events, and 26% of women had a history of pregnancy morbidity; half of the patients had a history of thrombocytopenia, and a third had valvulopathy. Before DAH, 55% of the patients were anticoagulated. At DAH onset, 65% of patients presented hemoptysis. The relapse rate was 47% at six months and 52% at one year. Triple positivity (HR 4.22, 95% CI 1.14-15.59) was associated with relapse at six months. The estimated mortality at one and five years was 30.3% and 45.8%. Factors associated with mortality were severe thrombocytopenia (< 50 K/µL) (HR 3.10, 95% CI 1.39-6.92), valve vegetations (HR 3.22, 95% CI 1.14-9.07), CAPS (HR 3.80, 95% CI 1.84-7.87), and requirement of MV (HR 2.22, 95% CI 1.03-4.80). Forty-two percent of patients required MV on the incident DAH episode. Patients presenting with severe thrombocytopenia (OR 6.42, 95% CI 1.77-23.30) or CAPS (OR 4.30, 95% CI 1.65-11.16) were more likely to require MV. CONCLUSION: APS-associated DAH is associated with high morbidity and mortality, particularly when presenting with triple positivity, thrombocytopenia, valvular involvement, and CAPS.

Adapting enzymes to improve their functionality in plants: why and how.

Synthetic biology creates new metabolic processes and improves existing ones using engineered or natural enzymes. These enzymes are often sourced from cells that differ from those in the target plant organ with respect to, e.g. redox potential, effector levels, or proteostasis machinery. Non-native enzymes may thus need to be adapted to work well in their new plant context ('plantized') even if their specificity and kinetics in vitro are adequate. Hence there are two distinct ways in which an enzyme destined for use in plants can require improvement: In catalytic properties such as substrate and product specificity, kcat, and KM; and in general compatibility with the milieu of cells that express the enzyme. Continuous directed evolution systems can deliver both types of improvement and are so far the most broadly effective way to deliver the second type. Accordingly, in this review we provide a short account of continuous evolution methods, emphasizing the yeast OrthoRep system because of its suitability for plant applications. We then cover the down-to-earth and increasingly urgent issues of which enzymes and enzyme properties can - or cannot - be improved in theory, and which in practice are the best to target for crop improvement, i.e. those that are realistically improvable and important enough to warrant deploying continuous directed evolution. We take horticultural crops as examples because of the opportunities they present and to sharpen the focus.

Large vessel involvement in antineutrophil cytoplasmic antibody-associated vasculitis.

OBJECTIVES: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is currently categorized under the small vessel vasculitides. There is limited knowledge about large vessel involvement in AAV (L-AAV), mainly described in case reports and small series. L-AAV can involve temporal arteries (TA-AAV), aorta (A-AAV), and periaortic soft tissue (PA-AAV). We sought to characterize the features of patients with L-AAV. METHODS: Patients older than 18 years at diagnosis of TA-AAV, A-AAV and PA-AAV seen at the Mayo Clinic, Rochester between January 1, 2000, and December 31, 2021, were identified through a proprietary medical text search algorithm. Patients were included if diagnosed with L-AAV, fulfilled 2022 ACR/EULAR classification criteria for GPA, MPA, or EGPA, had positive ANCA test results, and had more than one outpatient or inpatient visit. RESULTS: The study cohort consists of 36 patients with L-AAV. Of those, 23 had p-ANCA and/or MPO-ANCA; 13 had c-ANCA and/or PR3-ANCA. Mean (SD) age at AAV diagnosis was 63.4 (12.79); 20 (56%) were male. Seventeen patients had TA-AAV, 10 had A-AAV and 9 had PA-AAV. Most patients (n = 25, 69%) were diagnosed with large vessel vasculitis and AAV within a one-year timespan. Twenty-five (69%) patients had histopathologic confirmation of AAV diagnosis in a location other than temporal artery, aorta, or periaortic soft tissue. Glucocorticoids (36/36), rituximab (19/36), and methotrexate (18/36) were the most frequent treatments. CONCLUSIONS: This is the largest single-center cohort of patients with L-AAV to date. AAV can involve large arteries, albeit infrequent. AAV-targeted therapy should be considered in patients with L-AAV.

Using continuous directed evolution to improve enzymes for plant applications.

Continuous directed evolution of enzymes and other proteins in microbial hosts is capable of outperforming classical directed evolution by executing hypermutation and selection concurrently in vivo, at scale, with minimal manual input. Provided that a target enzyme's activity can be coupled to growth of the host cells, the activity can be improved simply by selecting for growth. Like all directed evolution, the continuous version requires no prior mechanistic knowledge of the target. Continuous directed evolution is thus a powerful way to modify plant or non-plant enzymes for use in plant metabolic research and engineering. Here, we first describe the basic features of the yeast (Saccharomyces cerevisiae) OrthoRep system for continuous directed evolution and compare it briefly with other systems. We then give a step-by-step account of three ways in which OrthoRep can be deployed to evolve primary metabolic enzymes, using a THI4 thiazole synthase as an example and illustrating the mutational outcomes obtained. We close by outlining applications of OrthoRep that serve growing demands (i) to change the characteristics of plant enzymes destined for return to plants, and (ii) to adapt ("plantize") enzymes from prokaryotes-especially exotic prokaryotes-to function well in mild, plant-like conditions.

Non-invasive hemoglobin estimation for preoperative anemia screening.

BACKGROUND: Preoperative anemia is common and associated with adverse postoperative outcomes. Assessment of hemoglobin concentrations may facilitate optimization prior to surgery. However, phlebotomy-based hemoglobin measurement may contribute to patient discomfort and iatrogenic blood loss, which makes non-invasive hemoglobin estimation attractive in this setting. STUDY DESIGN AND METHODS: This is a prospective study of adult patients presenting for preoperative evaluation before elective surgery at a tertiary care medical center. The Masimo Pronto Pulse CO-Oximeter was utilized to estimate blood hemoglobin concentrations (SpHb), which were then compared with hemoglobin concentrations obtained via complete blood count. Receiver operating curves were used to identify SpHb values maximizing specificity for anemia detection while meeting a minimum sensitivity of 80%. RESULTS: A total of 122 patients were recruited with a median (interquartile range) age of 66 (58, 72) years. SpHb measurements were obtained in 112 patients (92%). SpHb generally overestimated hemoglobin with a mean (± 1.96 × standard deviation) difference of 0.8 (-2.2, 3.9) g/dL. Preoperative anemia, defined by hemoglobin <12.0 g/dL in accordance with institutional protocol, was present in 22 patients (20%). The optimal SpHb cut-point to identify anemia was 13.5 g/dL: sensitivity 86%, specificity 81%, negative predictive value 96%, and positive predictive value 53%. Utilizing this cut-point, 60% (73/122) of patients could have avoided phlebotomy-based hemoglobin assessment, while an anemia diagnosis would have been missed in <3% (3/122). CONCLUSION: The use of SpHb devices for anemia screening in surgical patients is feasible with the potential to reliably rule-out anemia despite limited accuracy.

Postoperative Transfusions after Administration of Delayed Cold-stored Platelets versus Room Temperature Platelets in Cardiac Surgery: A Retrospective Cohort Study.

BACKGROUND: Delayed cold storage of room temperature platelets may extend shelf life from 5 to 14 days. The study hypothesized that the use of delayed cold-stored platelets in cardiac surgery would be associated with decreased postoperative platelet count increments but similar transfusion and clinical outcomes compared to room temperature-stored platelets. METHODS: This is an observational cohort study of adults transfused with platelets intraoperatively during elective cardiac surgery between April 2020 and May 2021. Intraoperative platelets were either room temperature-stored or delayed cold-stored based on blood bank availability rather than clinical features or provider preference. Differences in transfusion and clinical outcomes, including a primary outcome of allogenic transfusion exposure in the first 24 h postoperatively, were compared between groups. RESULTS: A total of 713 patient encounters were included: 529 (74%) room temperature-stored platelets and 184 (26%) delayed cold-stored platelets. Median (interquartile range) intraoperative platelet volumes were 1 (1 to 2) units in both groups. Patients receiving delayed cold-stored platelets had higher odds of allogeneic transfusion in the first 24 h postoperatively (81 of 184 [44%] vs. 169 of 529 [32%]; adjusted odds ratio, 1.65; 95% CI, 1.13 to 2.39; P = 0.009), including both erythrocytes (65 of 184 [35%] vs. 135 of 529 [26%]; adjusted odds ratio, 1.54; 95% CI, 1.03 to 2.29; P = 0.035) and platelets (48 of 184 [26%] vs. 79 of 529 [15%]; adjusted odds ratio, 1.91; 95% CI, 1.22 to 2.99; P = 0.005). There was no difference in the number of units administered postoperatively among those transfused. Platelet counts were modestly lower in the delayed cold-stored platelet group (-9 × 109/l; 95% CI, -16 to -3]) through the first 3 days postoperatively. There were no significant differences in reoperation for bleeding, postoperative chest tube output, or clinical outcomes. CONCLUSIONS: In adults undergoing cardiac surgery, delayed cold-stored platelets were associated with higher postoperative transfusion utilization and lower platelet counts compared to room temperature-stored platelets without differences in clinical outcomes. The use of delayed cold-stored platelets in this setting may offer a viable alternative when facing critical platelet inventories but is not recommended as a primary transfusion approach.

Intrathecal Opioid Use in Kidney Transplantation: An Observational Cohort Study.

BACKGROUND: Kidney transplant is the most common transplant operation performed in the United States. Although various approaches to pain management have been described, the optimal analgesic strategy remains undefined. Specifically, the role of intrathecal opioids in this patient population has not been comprehensively evaluated. METHODS: Using a retrospective cohort design, data from kidney transplant operations at a single tertiary care medical center between August 1, 2017, and July 31, 2022, were extracted. Inverse probability of treatment weighting (IPTW) was used to assess differences in clinical outcomes based on the presence or absence of intrathecal opioid administration before surgical incision. The primary outcome was total opioid exposure expressed in milligram morphine equivalents (MME) in the first 72 hours postoperatively, with secondary outcomes including total MME (intraoperative plus postoperative MME, postoperative pain scores, and the presence of postoperative nausea/vomiting [PONV], pruritus, or adverse events). RESULTS: A total of 1014 kidney transplants in 1012 unique patients were included, with 411 (41%) receiving intrathecal opioids preoperatively. Hydromorphone was the intrathecal opioid used in all cases with median dose of 100 µg (interquartile range [IQR], 100, 100; range 50-200). Subjects receiving intrathecal opioids had significantly lower postoperative opioid requirements at 72 hours (30 [0-68] vs 64 [22, 120] MME), with ratio of geometric means in the IPTW analysis (ratio of geometric means 0.34, 95% confidence interval [CI], 0.26-0.43; P < .001). Similar findings were observed for total opioids (45 [30-75] vs 75 [60-90] MME; ratio of geometric means 0.58, 95% CI, 0.54-0.63; P < .001). Maximum reported pain scores in the intrathecal group were lower at 24 hours (4 [2-7] vs 7 [5, 8]; OR, 0.28; 95% CI, 0.21-0.37 for experiencing a higher pain score with intrathecal opioids, P < .001) and 72 hours (6 [4-7] vs 7 [5-8]; OR, 0.41; 95% CI, 0.31-0.54; P < .001). Patients receiving intrathecal opioids were more likely to experience PONV (225 of 411 [55%] vs 232 of 603 [38%]; OR, 2.16; 95% CI, 1.63-2.86; P < .001). CONCLUSIONS: Intrathecal opioid administration was associated with improved pain outcomes in patients undergoing kidney transplantation, including lower opioid requirements and pain scores through 72 hours. However, this was accompanied by an increased risk of PONV.

Effect of an oxytocin protocol on secondary uterotonic use in patients undergoing Cesarean delivery.

PURPOSE: Protocol-driven oxytocin regimens can reduce oxytocin administration compared with a nonprotocol free-flow continuous infusion. Our aim was to compare secondary uterotonic use between a modified "rule of threes" oxytocin protocol and a free-flow continuous oxytocin infusion after Cesarean delivery. METHODS: We conducted a retrospective before-and-after study to compare patients who underwent Cesarean delivery between 1 January 2010 and 31 December 2013 (preprotocol) with patients who underwent Cesarean delivery between 1 January 2015 and 31 August 2017 (postprotocol). The preprotocol group received free-flow oxytocin administration and the postprotocol group received oxytocin according to a modified rule of threes algorithm. The primary outcome was secondary uterotonic use and the secondary outcomes included blood transfusion, hemoglobin value < 8 g·dL-1, and estimated blood loss. RESULTS: In total, 4,010 Cesarean deliveries were performed in 3,637 patients (2,262 preprotocol and 1,748 postprotocol). The odds of receiving secondary uterotonic drugs were increased in the postprotocol group (odds ratio [OR], 1.33; 95% confidence interval [CI], 1.04 to 1.70; P = 0.02). Patients in the postprotocol group were less likely to receive a blood transfusion. Nevertheless, the two groups were similar for the composite end point of transfusion or hemoglobin < 8 g·dL-1 (OR, 0.86; 95% CI, 0.66 to 1.11; P = 0.25). The odds of an estimated blood loss greater than 1,000 mL were reduced in the postprotocol group (OR, 0.64; 95% CI, 0.50 to 0.84; P = 0.001). CONCLUSIONS: Patients in the modified rule of threes oxytocin protocol group were more likely to receive a secondary uterotonic than those in the preprotocol group. Estimated blood loss and transfusion outcomes were similar.

RéSUMé: OBJECTIF: Les schémas thérapeutiques d'ocytocine basés sur un protocole peuvent réduire l'administration d'ocytocine par rapport à une perfusion continue en débit libre hors protocole. Notre objectif était de comparer l'utilisation secondaires d'agents utérotoniques entre un protocole modifié d'ocytocine en « règle de trois ¼ et une perfusion continue d'ocytocine à débit libre après un accouchement par césarienne. MéTHODE: Nous avons mené une étude rétrospective avant-après pour comparer les personnes ayant bénéficié d'une césarienne entre le 1er janvier 2010 et le 31 décembre 2013 (pré-protocole) avec les personnes ayant subi une césarienne entre le 1er janvier 2015 et le 31 août 2017 (post-protocole). Le groupe pré-protocole a reçu une administration d'ocytocine en débit libre et le groupe post-protocole a reçu de l'ocytocine selon un algorithme de règle de trois modifié. Le critère d'évaluation principal était l'utilisation secondaire d'agents utérotoniques et les critères d'évaluation secondaires incluaient la transfusion sanguine, un indice d'hémoglobine < 8 g·dL­1 et les pertes de sang estimées. RéSULTATS: Au total, 4010 accouchements par césarienne ont été réalisés chez 3637 patient·es (2262 pré-protocole et 1748 post-protocole). Les chances de recevoir des médicaments utérotoniques secondaires étaient plus élevées dans le groupe post-protocole (rapport de cotes [RC], 1,33; intervalle de confiance [IC] à 95 %, 1,04 à 1,70; P = 0,02). Les patient·es du groupe post-protocole étaient moins susceptibles de recevoir une transfusion sanguine. Néanmoins, les deux groupes étaient similaires en ce qui touchait au critère d'évaluation composite de transfusion ou d'hémoglobine < 8 g·dL­1 (RC, 0,86; IC 95, 0,66 à 1,11; P = 0,25). Les risques d'une perte de sang estimée supérieure à 1000 mL ont été réduits dans le groupe post-protocole (RC, 0,64; IC 95 %, 0,50 à 0,84; P = 0,001). CONCLUSION: Les patient·es du groupe du protocole d'ocytocine en règle de trois modifiée étaient plus susceptibles de recevoir un utérotonique secondaire que les personnes du groupe pré-protocole. Les pertes sanguines estimées et les résultats transfusionnels étaient similaires.

Coagulation Tests and Bleeding Classification After Cardiopulmonary Bypass: A Prospective Study.

OBJECTIVE: No recent prospective studies have analyzed the accuracy of standard coagulation tests and thromboelastography (TEG) to identify patients with excessive microvascular bleeding following cardiopulmonary bypass (CPB). The aim of this study was to assess the value of coagulation profile tests, as well as TEG, for the classification of microvascular bleeding after CPB. DESIGN: A prospective observational study. SETTING: At a single-center academic hospital. PARTICIPANTS: Patients ≥18 years of age undergoing elective cardiac surgery. INTERVENTIONS: Qualitative assessment of microvascular bleeding post-CPB (surgeon and anesthesiologist consensus) and the association with coagulation profile tests and TEG values. MEASUREMENTS AND MAIN RESULTS: A total of 816 patients were included in the study-358 (44%) bleeders and 458 (56%) nonbleeders. Accuracy, sensitivity, and specificity for the coagulation profile tests and TEG values ranged from 45% to 72%. The predictive utility was similar across tests, with prothrombin time (PT) (62% accuracy, 51% sensitivity, 70% specificity), international normalized ratio (INR) (62% accuracy, 48% sensitivity, 72% specificity), and platelet count (62% accuracy, 62% sensitivity, 61% specificity) displaying the highest performance. Secondary outcomes were worse in bleeders versus nonbleeders, including higher chest tube drainage, total blood loss, transfusion of red blood cells, reoperation rates (p < 0.001, respectively), readmission within 30 days (p = 0.007), and hospital mortality (p = 0.021). CONCLUSIONS: Standard coagulation tests and individual components of TEG in isolation agree poorly with the visual classification of microvascular bleeding after CPB. The PT-INR and platelet count performed best but had low accuracy. Further work is warranted to identify better testing strategies to guide perioperative transfusion decisions in cardiac surgical patients.

Association of Blood Pressure Variability with Delirium in Patients with Critical Illness.

BACKGROUND: The objective was to examine the association of blood pressure variability (BPV) during the first 24 h after intensive care unit admission with the likelihood of delirium and depressed alertness without delirium ("depressed alertness"). METHODS: This retrospective, observational, cohort study included all consecutive adult patients admitted to an intensive care unit at Mayo Clinic, Rochester, Minnesota, from July 1, 2004, through October 31, 2015. The primary outcomes were delirium and delirium-free days, and the secondary outcomes included depressed alertness and depressed alertness-free days. Logistic regression was performed to determine the association of BPV with delirium and depressed alertness. Proportional odds regression was used to assess the association of BPV with delirium-free days and depressed alertness-free days. RESULTS: Among 66,549 intensive care unit admissions, delirium was documented in 20.2% and depressed alertness was documented in 24.4%. Preserved cognition was documented in 55.4% of intensive care unit admissions. Increased systolic and diastolic BPV was associated with an increased odds of delirium and depressed alertness. The magnitude of the association per 5-mm Hg increase in systolic average real variability (the average of absolute value of changes between consecutive systolic blood pressure readings) was greater for delirium (odds ratio 1.34; 95% confidence interval 1.29-1.40; P < 0.001) than for depressed alertness (odds ratio 1.06; 95% confidence interval 1.02-1.10; P = 0.004). Increased systolic and diastolic BPV was associated with fewer delirium-free days but not with depressed alertness-free days. CONCLUSIONS: BPV in the first 24 h after intensive care unit admission is associated with an increased likelihood of delirium and fewer delirium-free days.

Disparities in Hypoxemia Detection by Pulse Oximetry Across Self-Identified Racial Groups and Associations With Clinical Outcomes.

OBJECTIVES: To assess disparities in hypoxemia detection by pulse oximetry across self-identified racial groups and associations with clinical outcomes. DESIGN: Observational cohort study from May 5, 2018, to December 31, 2020. SETTING: Three academic medical centers in the United States. PATIENTS: Adults greater than or equal to 18 years who self-identified as White, Black, Asian, or American Indian admitted to the ICU or undergoing surgery during inpatient hospitalization with simultaneous measurements of pulse oximetry-estimated oxygen saturation and arterial blood gas-derived oxygen saturation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Multivariable models were employed to assess the relationships between race, occult hypoxemia (i.e., arterial blood gas-derived oxygen saturation < 88% despite pulse oximetry-estimated oxygen saturation ≥ 92%), and clinical outcomes of hospital mortality and hospital-free days. One-hundred twenty-eight-thousand two-hundred eighty-five paired pulse oximetry-estimated oxygen saturation-arterial blood gas-derived oxygen saturation measurements were included from 26,603 patients. Pulse oximetry-estimated oxygen saturation on average overestimated arterial blood gas-derived oxygen saturation by 1.57% (1.54-1.61%). Black, Asian, and American Indian patients were more likely to experience occult hypoxemia during hospitalization (estimated probability 6.2% [5.1-7.6%], 6.6% [4.9-8.8%], and 6.6% [4.4-10.0%], respectively) compared with White patients (3.6% [3.4-3.8%]). Black patients had increased odds of occult hypoxemia compared with White patients after adjustment (odds ratio, 1.65; 1.28-2.14; p < 0.001). Differences in occult hypoxemia between Asian and American Indian patients compared with White patients were not significant after adjustment (odds ratio, 1.53; 0.95-2.47; p = 0.077 and odds ratio, 1.31; 0.80-2.16; p = 0.288, respectively). Occult hypoxemia was associated with increased odds of mortality in surgical (odds ratio, 2.96; 1.20-7.28; p = 0.019) and ICU patients (1.36; 1.03-1.80; p = 0.033). Occult hypoxemia was associated with fewer hospital-free days in surgical (-2.5 d [-3.9 to -1.2 d]; p < 0.001) but not ICU patients (0.4 d [-0.7 to 1.4 d]; p = 0.500). CONCLUSIONS: Occult hypoxemia is more common in Black patients compared with White patients and is associated with increased mortality, suggesting potentially important outcome implications for undetected hypoxemia. It is imperative to validate pulse oximetry with expanded racial inclusion.

Chemical-damage MINE: A database of curated and predicted spontaneous metabolic reactions.

Spontaneous reactions between metabolites are often neglected in favor of emphasizing enzyme-catalyzed chemistry because spontaneous reaction rates are assumed to be insignificant under physiological conditions. However, synthetic biology and engineering efforts can raise natural metabolites' levels or introduce unnatural ones, so that previously innocuous or nonexistent spontaneous reactions become an issue. Problems arise when spontaneous reaction rates exceed the capacity of a platform organism to dispose of toxic or chemically active reaction products. While various reliable sources list competing or toxic enzymatic pathways' side-reactions, no corresponding compilation of spontaneous side-reactions exists, nor is it possible to predict their occurrence. We addressed this deficiency by creating the Chemical Damage (CD)-MINE resource. First, we used literature data to construct a comprehensive database of metabolite reactions that occur spontaneously in physiological conditions. We then leveraged this data to construct 148 reaction rules describing the known spontaneous chemistry in a substrate-generic way. We applied these rules to all compounds in the ModelSEED database, predicting 180,891 spontaneous reactions. The resulting (CD)-MINE is available at https://minedatabase.mcs.anl.gov/cdmine/#/home and through developer tools. We also demonstrate how damage-prone intermediates and end products are widely distributed among metabolic pathways, and how predicting spontaneous chemical damage helps rationalize toxicity and carbon loss using examples from published pathways to commercial products. We explain how analyzing damage-prone areas in metabolism helps design effective engineering strategies. Finally, we use the CD-MINE toolset to predict the formation of the novel damage product N-carbamoyl proline, and present mass spectrometric evidence for its presence in Escherichia coli.

Renal Function Parameters and Serum Sodium Enhance Prediction of Wait-List Outcomes in Pediatric Liver Transplantation.

BACKGROUND AND AIMS: Reliance on exception points to prioritize children for liver transplantation (LT) stems from concerns that the Pediatric End-Stage Liver Disease (PELD) score underestimates mortality. Renal dysfunction and serum sodium disturbances are negative prognosticators in adult LT candidates and various pediatric populations, but are not accounted for in PELD. We retrospectively evaluated the effect of these parameters in predicting 90-day wait-list death/deterioration among pediatric patients (<12 years) listed for isolated LT in the United States between February 2002 and June 2018. APPROACH AND RESULTS: Among 4,765 patients, 2,303 (49.3%) were transplanted, and 231 (4.8%) died or deteriorated beyond transplantability within 90 days of listing. Estimated glomerular filtration rate (eGFR) (hazard ratio [HR] 1.09 per 5-unit decrease, 95% confidence interval [CI] 1.06-1.10) and dialysis (HR 7.24, 95% CI 3.57-14.66) were univariate predictors of 90-day death/deterioration (P < 0.001). The long-term benefit of LT persisted in patients with renal dysfunction, with LT as a time-dependent covariate conferring a 2.4-fold and 17-fold improvement in late survival among those with mild and moderate-to-severe dysfunction, respectively. Adjusting for PELD, sodium was a significant nonlinear predictor of outcome, with 90-day death/deterioration risk increased at both extremes of sodium (HR 1.20 per 1-unit decrease below 137 mmol/L, 95% CI 1.16-1.23; HR per 1-unit increase above 137 mmol/L 1.13, 95% CI 1.10-1.17, P < 0.001). A multivariable model incorporating PELD, eGFR, dialysis, and sodium demonstrated improved performance and superior calibration in predicting wait-list outcomes relative to the PELD score. CONCLUSIONS: Listing eGFR, dialysis, and serum sodium are potent, independent predictors of 90-day death/deterioration in pediatric LT candidates, capturing risk not accounted for by PELD. Incorporation of these variables into organ allocation systems may highlight patient subsets with previously underappreciated risk, augment ability of PELD to prioritize patients for transplantation, and ultimately mitigate reliance on nonstandard exceptions.

Association of hypothyroidism with outcomes in hospitalized adults with COVID-19: Results from the International SCCM Discovery Viral Infection and Respiratory Illness Universal Study (VIRUS): COVID-19 Registry.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is associated with high rates of morbidity and mortality. Primary hypothyroidism is a common comorbid condition, but little is known about its association with COVID-19 severity and outcomes. This study aims to identify the frequency of hypothyroidism in hospitalized patients with COVID-19 as well as describe the differences in outcomes between patients with and without pre-existing hypothyroidism using an observational, multinational registry. METHODS: In an observational cohort study we enrolled patients 18 years or older, with laboratory-confirmed severe acute respiratory syndrome coronavirus-2 infection between March 2020 and February 2021. The primary outcomes were (1) the disease severity defined as per the World Health Organization Scale for Clinical Improvement, which is an ordinal outcome corresponding with the highest severity level recorded during a patient's index COVID-19 hospitalization, (2) in-hospital mortality and (3) hospital-free days. Secondary outcomes were the rate of intensive care unit (ICU) admission and ICU mortality. RESULTS: Among the 20,366 adult patients included in the study, pre-existing hypothyroidism was identified in 1616 (7.9%). The median age for the Hypothyroidism group was 70 (interquartile range: 59-80) years, and 65% were female and 67% were White. The most common comorbidities were hypertension (68%), diabetes (42%), dyslipidemia (37%) and obesity (28%). After adjusting for age, body mass index, sex, admission date in the quarter year since March 2020, race, smoking history and other comorbid conditions (coronary artery disease, hypertension, diabetes and dyslipidemia), pre-existing hypothyroidism was not associated with higher odds of severe disease using the World Health Organization disease severity index (odds ratio [OR]: 1.02; 95% confidence interval [CI]: 0.92, 1.13; p = .69), in-hospital mortality (OR: 1.03; 95% CI: 0.92, 1.15; p = .58) or differences in hospital-free days (estimated difference 0.01 days; 95% CI: -0.45, 0.47; p = .97). Pre-existing hypothyroidism was not associated with ICU admission or ICU mortality in unadjusted as well as in adjusted analysis. CONCLUSIONS: In an international registry, hypothyroidism was identified in around 1 of every 12 adult hospitalized patients with COVID-19. Pre-existing hypothyroidism in hospitalized patients with COVID-19 was not associated with higher disease severity or increased risk of mortality or ICU admissions. However, more research on the possible effects of COVID-19 on the thyroid gland and its function is needed in the future.

Engineering Strategies to Boost Crop Productivity by Cutting Respiratory Carbon Loss.

Roughly half the carbon that crop plants fix by photosynthesis is subsequently lost by respiration. Nonessential respiratory activity leading to unnecessary CO2 release is unlikely to have been minimized by natural selection or crop breeding, and cutting this large loss could complement and reinforce the currently dominant yield-enhancement strategy of increasing carbon fixation. Until now, however, respiratory carbon losses have generally been overlooked by metabolic engineers and synthetic biologists because specific target genes have been elusive. We argue that recent advances are at last pinpointing individual enzyme and transporter genes that can be engineered to (1) slow unnecessary protein turnover, (2) replace, relocate, or reschedule metabolic activities, (3) suppress futile cycles, and (4) make ion transport more efficient, all of which can reduce respiratory costs. We identify a set of engineering strategies to reduce respiratory carbon loss that are now feasible and model how implementing these strategies singly or in tandem could lead to substantial gains in crop productivity.

Hemodynamics in Patients With Pheochromocytoma or Paraganglioma Undergoing Non-neuroendocrine Operations.

INTRODUCTION: Surgical resection of pheochromocytoma and paraganglioma (PPGL) may be associated with excessive hemodynamic variability. Whether hemodynamic variability occurs in patients with undiagnosed PPGL undergoing unrelated, non-neuroendocrine, operations is unknown. METHODS: We identified patients who underwent non-neuroendocrine surgical procedures up to 5 y before pathologic diagnosis of PPGL. For each PPGL, two non-PPGL patients were matched based on sex, age, type, and year of operation. Electronic medical records were reviewed for intraoperative blood pressures, heart rates, and hemodynamic variability was assessed with range (maximum-minimum), standard deviation, coefficient of variation, and average real variability. RESULTS: Thirty-seven PPGL patients underwent operations preceding the diagnosis of PPGL: 25 pheochromocytomas, 11 paragangliomas, and one metastatic pheochromocytoma. Median interquartile range tumor size at diagnosis was 35 mm (23 to 60). The time from index operation to PPGL diagnosis was ≤12 mo in 21 (56.8%) patients. In 23 (62.2%) patients, the subsequently diagnosed PPGL was functional. Fifteen (40.5%) PPGL and 20 (27.0%) control patients were preoperatively treated for hypertension (P = 0.149). Maximum intraoperative systolic BP was >180 mmHg for 4 (10.8%) PPGL patients and 3 (4.1%) controls (P = 0.219). Two PPGL patients had intraoperative systolic BP >230 mmHg. No significant differences were found with all other measures of intraoperative hemodynamic variability. Similarly, in secondary analysis there was no significant difference in intraoperative hemodynamic variability between biochemically active PPGL and their respective controls. CONCLUSIONS: Patients with undiagnosed PPGL undergoing a wide variety of non-neuroendocrine operations had intraoperative hemodynamic variability comparable to non-PPGL patients undergoing the same type of procedures.