Conformational flexibility in carbapenem hydrolysis drives substrate specificity of the class D carbapenemase OXA-24/40.

The evolution of multidrug resistance in Acinetobacter spp. increases the risk of our best antibiotics losing their efficacy. From a clinical perspective, the carbapenem-hydrolyzing class D ß-lactamase subfamily present in Acinetobacter spp. is particularly concerning because of its ability to confer resistance to carbapenems. The kinetic profiles of class D ß-lactamases exhibit variability in carbapenem hydrolysis, suggesting functional differences. To better understand the structure-function relationship between the carbapenem-hydrolyzing class D ß-lactamase OXA-24/40 found in Acinetobacter baumannii and carbapenem substrates, we analyzed steady-state kinetics with the carbapenem antibiotics meropenem and ertapenem and determined the structures of complexes of OXA-24/40 bound to imipenem, meropenem, doripenem, and ertapenem, as well as the expanded-spectrum cephalosporin cefotaxime, using X-ray crystallography. We show that OXA-24/40 exhibits a preference for ertapenem compared with meropenem, imipenem, and doripenem, with an increase in catalytic efficiency of up to fourfold. We suggest that superposition of the nine OXA-24/40 complexes will better inform future inhibitor design efforts by providing insight into the complicated and varying ways in which carbapenems are selected and bound by class D ß-lactamases.

Automated production of gene-modified chimeric antigen receptor T cells using the Cocoon Platform.

Autologous cell-based therapeutics have gained increasing attention in recent years because of their efficacy at treating diseases with limited therapeutic options. Chimeric antigen receptor (CAR) T-cell therapy has demonstrated clinical success in hematologic oncology indications, providing critically ill patients with a potentially curative therapy. Although engineered cell therapies such as CAR T cells provide new options for patients with unmet needs, the high cost and complexity of manufacturing may hinder clinical and commercial translation. The Cocoon Platform (Lonza, Basel, Switzerland) addresses many challenges, such as high labor demand, process consistency, contamination risks and scalability, by enabling efficient, functionally closed and automated production, whether at clinical or commercial scale. This platform is customizable and easy to use and requires minimal operator interaction, thereby decreasing process variability. We present two processes that demonstrate the Cocoon Platform's capabilities. We employed different T-cell activation methods-OKT3 and CD3/CD28 Dynabeads (Thermo Fisher Scientific, Waltham, MA, USA)-to generate final cellular products that meet the critical quality attributes of a clinical autologous CAR T-cell product. This study demonstrates a manufacturing solution for addressing challenges with manual methods of production and facilitating the scale-up of autologous cell therapy.

Point-of-Care Ultrasound for Central Venous Assessment in the Emergency Department: A Prospective Study Comparing the Femoral and Internal Jugular Veins.

OBJECTIVES: The objective of this study was to estimate the width, height, and depth of the femoral vein (FV) and internal jugular vein (IJV), both sites of potential central line placement in children, using point-of-care ultrasound. METHODS: This was a prospective observational study. Point-of-care ultrasound was used to measure the width, height, and depth of the right FV and IJV in 100 children. The primary outcome was a comparison of the widths of the FV and the IJV in the same child. Our primary hypothesis was that the IJV would be wider than the FV. Secondary outcome measures included comparison of the heights and depths the FV and IJV and description of vessel overlap frequency between the 2 sites. RESULTS: A total of 106 children were enrolled, with 6 subjects excluded, and equally divided into 5 age groups (0-30 days, 1-24 months, 2-5 years, 6-11 years, and 12-17 years). The FV/IJV width ratios (95% confidence interval) by age were 0.58 (0.49-0.68), 0.53 (0.43-0.66), 0.57 (0.49-0.67), 0.68 (0.55-0.85), and 0.73 (0.62-0.85), all P < 0.002. The FV/IJV height ratios were <1 in all age groups, with P < 0.003 in the 4 youngest age groups. The FV/IJV depth ratios were >1 in 6 to 11 years (P = 0.018) and 12 to 17 years (P < 0.001). CONCLUSIONS: The IJV was significantly wider and taller than the FV in the same child in all age groups. The FV was significantly deeper than the IJV in children 6 years and older. This supports the use of the IJV as a potential site when placing ultrasound-guided central lines in children.

Sitting Time, Physical Activity, and Cognitive Impairment in Midlife and Older Adults.

This study cross-sectionally examines the relations of sitting and physical activity (PA) with cognitive impairment in community-dwelling adults aged 55-87 years (n = 3,780). Multivariable logistic regression assessed independent and joint relations of sitting and PA with Montreal Cognitive Assessment scores adjusting for covariates. Sitting ≥75% of the time and not meeting PA guidelines were related to 60% (95% confidence interval [CI] [1.19, 2.17]) and 27% (95% CI [1.06, 1.53]) higher odds for cognitive impairment, respectively. Stratification by age showed that sitting ≥75% of the time was associated with higher cognitive impairment odds in midlife (odds ratio [OR] = 1.86; 95% CI [1.31, 2.65]), but not older adults (OR = 1.06; 95% CI [0.57, 1.95]). Joint association analysis revealed that, overall, the highest odds for cognitive impairment were in those sitting ≥75% of the time while meeting or not meeting PA guidelines (OR = 1.69, 95% CI [1.13, 2.53]; and OR = 1.66, 95% CI [1.19, 2.32], respectively). In conclusion, prolonged sitting and insufficient PA are independent risk markers for cognitive impairment.

Cutaneous leukocyte lineages in tolerant large animal and immunosuppressed clinical vascularized composite allograft recipients.

Vascularized composite allografts (VCAs) can restore fully functional anatomic units in patients with limb amputations or severe facial tissue loss. However, acute rejection of the skin is frequently observed and underscores the importance of developing tolerance induction protocols. In this study, we have characterized the skin immune system in VCAs. We demonstrate infiltration of recipient leukocytes, regardless of rejection status, and in tolerant mixed hematopoietic chimeras, the co-existence of these cells with donor leukocytes in the absence of rejection. Here we characterize the dermal T cell and epidermal Langerhans cell components of the skin immune system in our porcine model of VCA tolerance, and the kinetics of cutaneous chimerism in both of these populations in VCAs transplanted to tolerant and nontolerant recipients, as well as in host skin. Furthermore, in biopsies from the first patient to receive a hand transplant in our program, we demonstrate the presence of recipient T cells in the skin of the transplanted limb in the absence of clinical or histological evidence of rejection.

Body mass, cardiorespiratory fitness, and cardiometabolic risk over time: Findings from the Cooper Center Longitudinal Study.

Few studies have adequately assessed the simultaneous effects of changes in cardiorespiratory fitness (fitness) and body mass on cardiometabolic risk. Hence, the current study's aims were twofold: (1) To determine whether increases in body mass result in higher cardiometabolic risk after controlling for fitness changes; and (2) To assess whether increases in fitness result in lower cardiometabolic risk after controlling for weight changes. The study consisted of 3534 patients who came for preventive medicine visits ≥4 times over any 10-year period (1979-2019). The primary independent variables were body mass and fitness, and the dependent variable was metabolic syndrome (MetS) and its components. Mixed-effects regression was used to model the relationship between changes in body mass, fitness, and MetS. Results indicate that increasing body mass up to a 10-year period was significantly related to increasing risk of MetS while controlling for changes in fitness. Specifically, a 1-kg increase in body mass was associated with a 17% (OR = 1.17; 95% CI 1.15-1.19) increased odds for MetS, while adjusting for fitness changes. A 1-MET increase in fitness was related to a 23% (OR = 0.77; 95% CI 0.70-0.84) decrease in odds for MetS, while adjusting for body mass changes up to 10 years. Moreover, body mass change was significantly related to changes in all cardiometabolic components of MetS. Fitness change was significantly associated with changes in MetS components. Future interventions should focus concurrently on increasing fitness and on body mass loss (or maintenance) to improve cardiometabolic health.

Keeping children healthy during and after COVID-19 pandemic: meeting youth physical activity needs.

BACKGROUND: The purpose of this study was to: 1) examine the maintenance of Physical Education and physical activity during the distance learning time, 2) determine the resources educators are utilizing to deliver PE curricula, and 3) understand the challenges experienced by educators during distance learning. METHODS: A survey was sent to a cohort of school-based fitness assessment software users. Respondents were largely school-based individuals including PE teachers (n = 1789), school (n = 62) and district administrators (n = 64), nurses (n = 3), and "other" (n = 522). RESULTS: Of 2440 respondents, most were from a city or suburb (69.7%), elementary or middle school (72.3%), and had Title 1 status (60.4%), an indicator of low socioeconomic status. Most campuses were closed during the COVID-19 pandemic (97.8%). Of the schools closed during the pandemic, only 2.8% had no prior PE requirements and that increased to 21% during the pandemic. In schools that remained open during the pandemic, 7.7% had no prior PE requirements and this increased to 60.5%. Importantly, 79% of respondents reported that students were either "significantly less" or "somewhat less" physically active during the closure. For closed schools, the most frequently cited challenges included "student access to online learning", "teacher/student communication" and "teacher remote work arrangements". For open schools, the most commonly reported challenges included "social distancing", "access to gymnasium/equipment", and "concern for personal health and wellbeing". CONCLUSION: The COVID-19 pandemic has caused important reductions in PE requirements and time engaged in physical activity. Challenges experienced by teachers were identified for closed and open schools.

Functional Movement Screening Performance and Association With Key Health Markers in Older Adults.

ABSTRACT: Farrell, SW, Pavlovic, A, Barlow, CE, Leonard, D, DeFina, JR, Willis, BL, DeFina, LF, and Haskell, WL. Functional movement screening performance and association with key health markers in older adults. J Strength Cond Res 35(11): 3021-3027, 2021-We examined Functional Movement Screening (FMS) performance and associations with key health markers among adults aged 55 years or older. Apparently healthy men (n = 425) and women (n = 158) completed a preventive medical examination between 2013 and 2018. Subjects were grouped by age and sex to determine mean scores for individual FMS items as well as total FMS score. We examined partial correlations between total FMS score and key health markers. We computed odds ratios (ORs) for having a total FMS score ≤14. The mean FMS scores for men and women were 11.7 ± 2.8 and 11.9 ± 2.3, respectively. Several differences were found between men who participated in FMS (takers) compared with FMS nontakers, whereas women FMS takers were generally similar to women FMS nontakers. After controlling for age, sex, and smoking, FMS scores were directly associated with physical activity (PA), cardiorespiratory fitness, frequency of resistance training, serum vitamin D, omega-3 index, low-density lipoprotein, and high-density lipoprotein (HDL)-cholesterol, and were inversely associated with body mass index (BMI), waist circumference (WC), blood glucose, HbA1c, and metabolic syndrome (p ≤ 0.02 for each). Adjusted OR for scoring ≤14 was significantly greater for those who were BMI and WC-obese, those with metabolic syndrome, those with low HDL-cholesterol, and those not meeting current PA guidelines. This study provides characteristics and mean values for FMS in a large older population and demonstrates that FMS performance is associated with key health markers. Prospective studies of older adults are needed to determine the utility of FMS in predicting future musculoskeletal injury and other chronic disease-related health outcomes.

Alcohol Use Disorder Masks the Effects of Childhood Adversity, Lifetime Trauma, and Chronic Stress on Hypothalamic-Pituitary-Adrenal Axis Reactivity.

BACKGROUND: Individuals with alcohol use disorder (AUD) and those who have experienced traumas or chronic stress exhibit dysregulated hypothalamic-pituitary-adrenal (HPA) axis reactivity. Whether and how trauma and stress histories interact with AUD to affect HPA axis reactivity has not been assessed. METHODS: In the present study, 26 healthy male controls and 70 abstinent men with AUD were administered a pharmacologic probe [ovine corticotropin-releasing hormone (oCRH)] and psychosocial stressor to assess HPA axis reactivity. Plasma adrenocorticotropin hormone (ACTH) and cortisol were assessed every 10-20 minutes. Hierarchical clustering of multiple measures of trauma and stress identified 3 distinct clusters: childhood adversity, lifetime trauma, and chronic stress. General linear model procedures were used to examine main effects of group (AUD/control) and interaction effects of the 3 clusters upon net-integrated ACTH and cortisol response. RESULTS: We found that higher levels of childhood adversity, lifetime trauma, and chronic stress were each associated with blunted oCRH-induced ACTH reactivity in controls, but not in the AUD group. Recent chronic stress within the prior 6 months had the strongest influence upon ACTH reactivity in the control group, and lifetime trauma, the least. CONCLUSIONS: Childhood adversity, lifetime trauma, and chronic stress likely exert persistent, measurable effects upon HPA axis functioning in healthy controls. This association appears to be masked in individuals with AUD, potentially confounding studies examining the effects of stress, adversity, and/or trauma upon the HPA axis in this population during the protracted withdrawal phase of recovery. Future work targeting stress exposure and reactivity should consider the heightened effect of previous alcohol use relative to past adversity and trauma.

Gastrointestinal stromal tumors of the colon and rectum.

Gastrointestinal stromal tumors (GISTs) are rare neoplasms, colorectal location being met in less than 5% of cases. Knowledge about this site related particularities are limited. The aim of this study is to present our experience with colorectal GISTs between 2005 and 2018 from the clinical, morphological, and immunohistochemical perspectives, with emphasis on prognostic factors. From a total of 203 gastrointestinal stromal tumors registered, 12 were colorectal (6%). The number of colonic tumors surpassed that of the rectum (9 : 3) and on the right side were registered more cases than on the left side (6/3). 9 were primary tumors and 3 were recurrences. Men and women were represented equally and the age range was between 22 and 76. Tumor dimensions varied between 0.5 and 14 cm. Microscopically, spindle cell type was dominant. Mitotic rate was variable between 1 and 115/50HPFs. Accordingly, for primary tumors progression risks were assigned (low risk: 2 cases, intermediate risk: 3 cases and high risk: 4 cases). All GISTs were CD117 and DOG1 positive. Four of the patients died of the disease.

Non-Neural (S-100 Negative) Bronchial Granular Cell Tumor Causing Acute Respiratory Failure.

Introduction: Endobronchial granular cell tumors are uncommon in the pediatric population. Case report: A 9-year-old female presented with respiratory failure due to an endobronchial tumor. After debulking and diagnosis, she underwent thoracotomy with right upper lobe resection and bronchoplasty. Pathology demonstrated an endobronchial S-100 negative granular cell tumor, which to our knowledge, is the first such report in the literature. Conclusion: Endobronchial granular cell tumors may cause obstructive respiratory failure, are amenable to surgery, and may be S-100 negative.

Cardiorespiratory Fitness, Coronary Artery Calcium, and Cardiovascular Disease Events in a Cohort of Generally Healthy Middle-Age Men: Results From the Cooper Center Longitudinal Study.

BACKGROUND: A robust literature demonstrates that coronary artery calcification (CAC) and cardiorespiratory fitness (CRF) are independent predictors of cardiovascular disease (CVD) events. Much less is known about the joint associations of CRF and CAC with CVD risk. In the setting of high CAC, high versus low CRF has been associated with decreased CVD events. The goal of this study was to assess the effect of continuous levels of CRF on CVD risk in the setting of increasing CAC burden. METHODS: We studied 8425 men without clinical CVD who underwent preventive medicine examinations that included an objective measurement of CRF and CAC between 1998 and 2007. There were 383 CVD events during an average follow-up of 8.4 years. Parametric proportional hazards regression models based on a Gompertz mortality rule were used to estimate total CVD incidence rates at 70 years of age as well as hazard ratios for the included covariates. RESULTS: CVD events increased with increasing CAC and decreased with increasing CRF. Adjusting for CAC level (scores of 0, 1-99, 100-399, and ≥400), for each additional MET of fitness, there was an 11% lower risk for CVD events (hazard ratio, 0.89; 95% confidence interval, 0.84-0.94). When CAC and CRF were considered together, there was a strong association between continuous CRF and CVD incidence rates in all CAC groups. CONCLUSIONS: In a large cohort of generally healthy men, there is an attenuation of CVD risk at all CAC levels with higher CRF.

Long-Term Association of Low-Density Lipoprotein Cholesterol With Cardiovascular Mortality in Individuals at Low 10-Year Risk of Atherosclerotic Cardiovascular Disease.

BACKGROUND: The associations of low-density lipoprotein cholesterol (LDL-C) with cardiovascular disease (CVD) and coronary heart disease mortality in an exclusively low estimated 10-year risk group are not well delineated. We sought to determine the long-term associations of various LDL-C and non-high-density lipoprotein cholesterol (HDL-C) thresholds and CVD and coronary heart disease mortality in a large, low 10-year risk cohort. METHODS: The study sample included participants of the CCLS (Cooper Center Longitudinal Study) without a history of CVD or diabetes mellitus and defined as low risk (<7.5%) for 10-year atherosclerotic CVD events at baseline based on Pooled Cohort Risk Assessment Equations. The associations of fasting LDL-C and non-HDL-C with CVD mortality were tested with Cox proportional hazards models. RESULTS: In 36 375 participants (72% men, median age 42) followed for a median of 26.8 years, 1086 CVD and 598 coronary heart disease deaths occurred. Compared with LDL-C <100 mg/dL, LDL-C categories 100 to 129 mg/dL, 130 to 159 mg/dL, 160 to 189.9 mg/dL, and ≥190 mg/dL were associated with a significantly higher risk of CVD death, with hazard ratios of 1.4 (95% CI, 1.1-1.7), 1.3 (95% CI, 1.1-1.6), 1.9 (95% CI, 1.5-2.4), and 1.7 (95% CI, 1.3-2.3), and mean reductions in years free of CVD death of 1.8, 1.1, 4.3, and 3.9, respectively. After adjustment for atherosclerotic CVD risk factors, LDL-C categories 160 to 189 mg/dL and ≥190 mg/dL remained independently associated with CVD mortality, with hazard ratios of 1.7 (95% CI, 1.4-2.2) and 1.5 (95% CI, 1.2-2.1), respectively. In multivariable-adjusted models using non-HDL-C <130 mg/dL as the reference, non-HDL-C 160 to 189 mg/dL, 190 to 219 mg/dL, and ≥220 mg/dL were significantly associated with CVD death, with hazard ratios of 1.3 (95% CI, 1.1-1.6), 1.8 (95% CI, 1.4-2.2), and 1.5 (95% CI, 1.2-2.0), respectively. Restricting the cohort to those with 10-year risk <5% did not diminish the associations of LDL-C and non-HDL-C with CVD mortality. CONCLUSIONS: In a low 10-year risk cohort with long-term follow-up, LDL-C and non-HDL-C ≥160 mg/dL were independently associated with a 50% to 80% increased relative risk of CVD mortality. These findings may have implications for future cholesterol treatment paradigms.

Multiple substitutions lead to increased loop flexibility and expanded specificity in Acinetobacter baumannii carbapenemase OXA-239.

OXA-239 is a class D carbapenemase isolated from an Acinetobacter baumannii strain found in Mexico. This enzyme is a variant of OXA-23 with three amino acid substitutions in or near the active site. These substitutions cause OXA-239 to hydrolyze late-generation cephalosporins and the monobactam aztreonam with greater efficiency than OXA-23. OXA-239 activity against the carbapenems doripenem and imipenem is reduced ∼3-fold and 20-fold, respectively. Further analysis demonstrated that two of the substitutions (P225S and D222N) are largely responsible for the observed alteration of kinetic parameters, while the third (S109L) may serve to stabilize the protein. Structures of OXA-239 with cefotaxime, doripenem and imipenem bound as acyl-intermediates were determined. These structures reveal that OXA-239 has increased flexibility in a loop that contains P225S and D222N. When carbapenems are bound, the conformation of this loop is essentially identical with that observed previously for OXA-23, with a narrow active site that makes extensive contacts to the ligand. When cefotaxime is bound, the loop can adopt a different conformation that widens the active site to allow binding of that bulky drug. This alternate conformation is made possible by P225S and further stabilized by D222N. Taken together, these results suggest that the three substitutions were selected to expand the substrate specificity profile of OXA-23 to cephalosporins and monobactams. The loss of activity against imipenem, however, suggests that there may be limits to the plasticity of class D enzymes with regard to evolving active sites that can effectively bind multiple classes of ß-lactam drugs.

Practical Catalytic Cleavage of C(sp3 )-C(sp3 ) Bonds in Amines.

The selective cleavage of thermodynamically stable C(sp3 )-C(sp3 ) single bonds is rare compared to their ubiquitous formation. Herein, we describe a general methodology for such transformations using homogeneous copper-based catalysts in the presence of air. The utility of this novel methodology is demonstrated for Cα -Cß bond scission in >70 amines with excellent functional group tolerance. This transformation establishes tertiary amines as a general synthon for amides and provides valuable possibilities for their scalable functionalization in, for example, natural products and bioactive molecules.

Hope as a Predictor of Anxiety and Depressive Symptoms Following Pediatric Cancer Diagnosis.

Objective: To examine hope and its components of agency and pathways as predictors of anxiety and depressive symptoms in children receiving cancer treatment. Methods: Sixty patients (mean standard deviation age = 13.3 (2.7); 57% male) completed Snyder's Hope Scales, the Children's Depression Inventory, and the State-Trait Anxiety Inventory at diagnosis and 3 month intervals for 1 year following pediatric cancer diagnosis. Parents also completed Snyder's Hope Scales. Linear mixed-effect regression was used to assess hope's role in longitudinal models of symptoms of depression and anxiety. Results: Agency was a significant predictor of between-patient differences and within-patient changes in symptoms of depression and anxiety. Neither patient pathways nor either component of parent hope was predictive of symptoms of depression or anxiety. Patients who were more likely to have depressive symptoms at baseline were older, diagnosed with leukemia, and non-Hispanic White as opposed to Hispanic. Patient demographics were not predictive of anxiety. Conclusions: Patient agency is a potential target for intervention to prevent or reduce anxiety and depressive symptoms following pediatric cancer diagnosis.

The Relationship between Cardiorespiratory Fitness and Montreal Cognitive Assessment Scores in Older Adults.

BACKGROUND: Relatively little is known regarding the association between objective measures of physical function such as cardiorespiratory fitness (CRF) and cognitive function tests in healthy older adults. OBJECTIVE: To evaluate the relationship between CRF and cognitive function in adults aged 55 and older. METHODS: Between 2008 and 2017, 4,931 men and women underwent a comprehensive preventive physical exam at the Cooper Clinic in Dallas, Texas. CRF was determined by duration of a maximal treadmill exercise test. Cognitive function was evaluated with the Montreal Cognitive Assessment (MoCA). In a multivariate model, adjusted odds ratios with 95% confidence intervals for MoCA scores < 26 (i.e., cognitive impairment) were determined by using CRF as both a continuous and a categorical variable. RESULTS: The mean age of the sample was 61.0 ± 6.0 years; mean maximal MET values were 10.0 ± 2.2. Mean MoCA scores were 26.9 ± 2.2; 23.4% of the sample had MoCA scores indicative of cognitive impairment. The odds ratio for cognitive impairment was 0.93 (0.88-0.97) per 1-MET increment in CRF. When examined as a categorical variable, and using the lowest CRF quintile as the referent, there was a significantly reduced likelihood for cognitive impairment across the remaining ordered CRF categories (p trend = 0.004). CONCLUSION: The association between CRF and MoCA score in older adults suggests that meeting or exceeding public health guidelines for physical activity is likely to increase CRF in low fit individuals, maintain CRF in those with a moderate to high level of CRF, and thereby help to maintain cognitive function in healthy older adults.

Nut consumption and metabolic syndrome in US adolescents.

OBJECTIVE: To determine whether nut intake is associated with the prevalence of metabolic syndrome in US adolescents. DESIGN: A cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) years 2003-2012. Anthropometric measurements, blood tests, 24 h diet recalls and demographic data were retrieved for participating adolescents. Metabolic syndrome was defined according to paediatric-modified Adult Treatment Panel III criteria. The exposure was defined as a nut intake ≥5 g/d. SETTING: USA. SUBJECTS: Individuals aged 12-19 years (n 2805). RESULTS: Nut consumption was associated with lower odds for metabolic syndrome (crude OR=0·25; 95 % CI 0·11, 0·55; P≤0·001). This effect was independent of age, sex, race/ethnicity and family income:poverty ratio (adjusted OR=0·27; 95 % CI 0·12, 0·61; P=0·002), and was stable after controlling for nutritional covariates including intake of sugar and total energy consumption (OR=0·36; 95 % CI 0·16, 0·81; P=0·014). CONCLUSION: Nut consumption of ≥5 g/d is independently associated with lower odds for metabolic syndrome in US adolescents.

Long-term outcomes of 176 patients with X-linked hyper-IgM syndrome treated with or without hematopoietic cell transplantation.

BACKGROUND: X-linked hyper-IgM syndrome (XHIGM) is a primary immunodeficiency with high morbidity and mortality compared with those seen in healthy subjects. Hematopoietic cell transplantation (HCT) has been considered a curative therapy, but the procedure has inherent complications and might not be available for all patients. OBJECTIVES: We sought to collect data on the clinical presentation, treatment, and follow-up of a large sample of patients with XHIGM to (1) compare long-term overall survival and general well-being of patients treated with or without HCT along with clinical factors associated with mortality and (2) summarize clinical practice and risk factors in the subgroup of patients treated with HCT. METHODS: Physicians caring for patients with primary immunodeficiency diseases were identified through the Jeffrey Modell Foundation, United States Immunodeficiency Network, Latin American Society for Immunodeficiency, and Primary Immune Deficiency Treatment Consortium. Data were collected with a Research Electronic Data Capture Web application. Survival from time of diagnosis or transplantation was estimated by using the Kaplan-Meier method compared with log-rank tests and modeled by using proportional hazards regression. RESULTS: Twenty-eight clinical sites provided data on 189 patients given a diagnosis of XHIGM between 1964 and 2013; 176 had valid follow-up and vital status information. Sixty-seven (38%) patients received HCT. The average follow-up time was 8.5 ± 7.2 years (range, 0.1-36.2 years). No difference in overall survival was observed between patients treated with or without HCT (P = .671). However, risk associated with HCT decreased for diagnosis years 1987-1995; the hazard ratio was significantly less than 1 for diagnosis years 1995-1999. Liver disease was a significant predictor of overall survival (hazard ratio, 4.9; 95% confidence limits, 2.2-10.8; P < .001). Among survivors, those treated with HCT had higher median Karnofsky/Lansky scores than those treated without HCT (P < .001). Among patients receiving HCT, 27 (40%) had graft-versus-host disease, and most deaths occurred within 1 year of transplantation. CONCLUSION: No difference in survival was observed between patients treated with or without HCT across all diagnosis years (1964-2013). However, survivors treated with HCT experienced somewhat greater well-being, and hazards associated with HCT decreased, reaching levels of significantly less risk in the late 1990s. Among patients treated with HCT, treatment at an early age is associated with improved survival. Optimism remains guarded as additional evidence accumulates.

Expanded Substrate Activity of OXA-24/40 in Carbapenem-Resistant Acinetobacter baumannii Involves Enhanced Binding Loop Flexibility.

Gram-negative bacteria resist ß-lactam antibiotics primarily by deploying ß-lactamase proteins that hydrolytically destroy the antibiotics. In clinical settings, these bacteria are producing variant ß-lactamases with "gain-of-activity" mutations that inactivate a broader range of ß-lactams. Learning how these mutations broaden substrate activity is important for coping with ß-lactam resistance. Here, we investigate a gain of activity mutation in OXA-24/40, a carbapenem-hydrolyzing class D ß-lactamase (CHDL) in Acinetobacter baumannii. OXA-24/40 was originally active against penicillin and carbapenem classes of ß-lactams, but a clinical variant of OXA-24/40, the single-site substitution mutant P227S, has emerged with expanded activity that now includes advanced cephalosporins and the monobactam aztreonam. Using solution-state nuclear magnetic resonance (NMR) spectroscopy, we have compared the site-specific backbone dynamics of wild-type OXA-24/40 and the P227S variant. P227S changes local backbone flexibility in segments that are important for both binding and hydrolysis of carbapenem and cephalosporin substrates. Our results suggest that mutation-induced changes in sequence-specific dynamics can expand substrate activity and thus highlight the role of protein conformational dynamics in antibiotic resistance. To the best of our knowledge, this is the first NMR study of CHDL conformational dynamics and its impact on the expansion of ß-lactam antibiotic resistance.