Metabolic engineering of Corynebacterium glutamicum for the production of pyrone and pyridine dicarboxylic acids.

Environmental concerns from plastic waste are driving interest in alternative monomers from bio-based sources. Pseudoaromatic dicarboxylic acids are promising alternatives with chemical structures similar to widely used petroleum-based aromatic dicarboxylic acids. However, their use in polyester synthesis has been limited due to production challenges. Here, we report the fermentative production of five pseudoaromatic dicarboxylic acids, including 2-pyrone-4,6-dicarboxylic acid (PDC) and pyridine dicarboxylic acids (PDCAs: 2,3-, 2,4-, 2,5-, and 2,6-PDCA), from glucose using five engineered Corynebacterium glutamicum strains. A platform C. glutamicum chassis strain was constructed by modulating the expression of nine genes involved in the synthesis and degradation pathways of precursor protocatechuate (PCA) and the glucose-uptake system. Comparative transcriptome analysis of the engineered strain against wild-type C. glutamicum identified iolE (NCgl0160) as a target for PDC production. Optimized fed-batch fermentation conditions enabled the final engineered strain to produce 76.17 ± 1.24 g/L of PDC. Using this platform strain, we constructed 2,3-, 2,4-, and 2,5-PDCA-producing strains by modulating the expression of key enzymes. Additionally, we demonstrated a previously uncharacterized pathway for 2,3-PDCA biosynthesis. The engineered strains produced 2.79 ± 0.005 g/L of 2,3-PDCA, 494.26 ± 2.61 mg/L of 2,4-PDCA, and 1.42 ± 0.02 g/L of 2,5-PDCA through fed-batch fermentation. To complete the portfolio, we introduced the 2,6-PDCA biosynthetic pathway to an L-aspartate pathway-enhanced C. glutamicum strain, producing 15.01 ± 0.03 g/L of 2,6-PDCA in fed-batch fermentation. The metabolic engineering strategies developed here will be useful for the production of pseudoaromatic chemicals.

Explainable Deep-Learning-Based Gait Analysis of Hip-Knee Cyclogram for the Prediction of Adolescent Idiopathic Scoliosis Progression.

Accurate prediction of scoliotic curve progression is crucial for guiding treatment decisions in adolescent idiopathic scoliosis (AIS). Traditional methods of assessing the likelihood of AIS progression are limited by variability and rely on static measurements. This study developed and validated machine learning models for classifying progressive and non-progressive scoliotic curves based on gait analysis using wearable inertial sensors. Gait data from 38 AIS patients were collected using seven inertial measurement unit (IMU) sensors, and hip-knee (HK) cyclograms representing inter-joint coordination were generated. Various machine learning algorithms, including support vector machine (SVM), random forest (RF), and novel deep convolutional neural network (DCNN) models utilizing multi-plane HK cyclograms, were developed and evaluated using 10-fold cross-validation. The DCNN model incorporating multi-plane HK cyclograms and clinical factors achieved an accuracy of 92% in predicting curve progression, outperforming SVM (55% accuracy) and RF (52% accuracy) models using handcrafted gait features. Gradient-based class activation mapping revealed that the DCNN model focused on the swing phase of the gait cycle to make predictions. This study demonstrates the potential of deep learning techniques, and DCNNs in particular, in accurately classifying scoliotic curve progression using gait data from wearable IMU sensors.

Microbial production of methyl anthranilate, a grape flavor compound.

Methyl anthranilate (MANT) is a widely used compound to give grape scent and flavor, but is currently produced by petroleum-based processes. Here, we report the direct fermentative production of MANT from glucose by metabolically engineered Escherichia coli and Corynebacterium glutamicum strains harboring a synthetic plant-derived metabolic pathway. Optimizing the key enzyme anthranilic acid (ANT) methyltransferase1 (AAMT1) expression, increasing the direct precursor ANT supply, and enhancing the intracellular availability and salvage of the cofactor S-adenosyl-l-methionine required by AAMT1, results in improved MANT production in both engineered microorganisms. Furthermore, in situ two-phase extractive fermentation using tributyrin as an extractant is developed to overcome MANT toxicity. Fed-batch cultures of the final engineered E. coli and C. glutamicum strains in two-phase cultivation mode led to the production of 4.47 and 5.74 g/L MANT, respectively, in minimal media containing glucose. The metabolic engineering strategies developed here will be useful for the production of volatile aromatic esters including MANT.

Analysis of Gait Characteristics Using Hip-Knee Cyclograms in Patients with Hemiplegic Stroke.

Gait disturbance is a common sequela of stroke. Conventional gait analysis has limitations in simultaneously assessing multiple joints. Therefore, we investigated the gait characteristics in stroke patients using hip-knee cyclograms, which have the advantage of simultaneously visualizing the gait kinematics of multiple joints. Stroke patients (n = 47) were categorized into two groups according to stroke severity, and healthy controls (n = 32) were recruited. An inertial measurement unit sensor-based gait analysis system, which requires placing seven sensors on the dorsum of both feet, the shafts of both tibias, the middle of both femurs, and the lower abdomen, was used for the gait analysis. Then, the hip-knee cyclogram parameters (range of motion, perimeter, and area) were obtained from the collected data. The coefficient of variance of the cyclogram parameters was obtained to evaluate gait variability. The cyclogram parameters differed between the stroke patients and healthy controls, and differences according to stroke severity were also observed. The gait variability parameters mainly differed in patients with more severe stroke, and specific visualized gait patterns of stroke patients were obtained through cyclograms. In conclusion, the hip-knee cyclograms, which show inter-joint coordination and visualized gait cycle in stroke patients, are clinically significant.

Microbial production of 4-amino-1-butanol, a four-carbon amino alcohol.

4-Amino-1-butanol (4AB) serves as an important intermediate compound for drugs and a precursor of biodegradable polymers used for gene delivery. Here, we report for the first time the fermentative production of 4AB from glucose by metabolically engineered Corynebacterium glutamicum harboring a newly designed pathway comprising a putrescine (PUT) aminotransferase (encoded by ygjG) and an aldehyde dehydrogenase (encoded by yqhD) from Escherichia coli, which convert PUT to 4AB. Application of several metabolic engineering strategies such as fine-tuning the expression levels of ygjG and yqhD, eliminating competing pathways, and optimizing culture condition further improved 4AB production. Fed-batch culture of the final metabolically engineered C. glutamicum strain produced 24.7 g/L of 4AB. The strategies reported here should be useful for the microbial production of primary amino alcohols from renewable resources.

Markerless gene knockout and integration to express heterologous biosynthetic gene clusters in Pseudomonas putida.

Pseudomonas putida has gained much interest among metabolic engineers as a workhorse for producing valuable natural products. While a few gene knockout tools for P. putida have been reported, integration of heterologous genes into the chromosome of P. putida, an essential strategy to develop stable industrial strains producing heterologous bioproducts, requires development of a more efficient method. Current methods rely on time-consuming homologous recombination techniques and transposon-mediated random insertions. Here we report a RecET recombineering system for markerless integration of heterologous genes into the P. putida chromosome. The efficiency and capacity of the recombineering system were first demonstrated by knocking out various genetic loci on the P. putida chromosome with knockout lengths widely spanning 0.6-101.7 kb. The RecET recombineering system developed here allowed successful integration of biosynthetic gene clusters for four proof-of-concept bioproducts, including protein, polyketide, isoprenoid, and amino acid derivative, into the target genetic locus of P. putida chromosome. The markerless recombineering system was completed by combining Cre/lox system and developing efficient plasmid curing systems, generating final strains free of antibiotic markers and plasmids. This markerless recombineering system for efficient gene knockout and integration will expedite metabolic engineering of P. putida, a bacterial host strain of increasing academic and industrial interest.

Focused ultrasound-mediated noninvasive blood-brain barrier modulation: preclinical examination of efficacy and safety in various sonication parameters.

OBJECTIVE The application of pharmacological therapeutics in neurological disorders is limited by the ability of these agents to penetrate the blood-brain barrier (BBB). Focused ultrasound (FUS) has recently gained attention for its potential application as a method for locally opening the BBB and thereby facilitating drug delivery into the brain parenchyma. However, this method still requires optimization to maximize its safety and efficacy for clinical use. In the present study, the authors examined several sonication parameters of FUS influencing BBB opening in small animals. METHODS Changes in BBB permeability were observed during transcranial sonication using low-intensity FUS in 20 adult male Sprague-Dawley rats. The authors examined the effects of FUS sonication with different sonication parameters, varying acoustic pressure, center frequency, burst duration, microbubble (MB) type, MB dose, pulse repetition frequency (PRF), and total exposure time. The focal region of BBB opening was identified by Evans blue dye. Additionally, H & E staining was used to identify blood vessel damage. RESULTS Acoustic pressure amplitude and burst duration were closely associated with enhancement of BBB opening efficiency, but these parameters were also highly correlated with tissue damage in the sonicated region. In contrast, MB types, MB dose, total exposure time, and PRF had an influence on BBB opening without conspicuous tissue damage after FUS sonication. CONCLUSIONS The study aimed to identify these influential conditions and provide safety and efficacy values for further studies. Future work based on the current results is anticipated to facilitate the implementation of FUS sonication for drug delivery in various CNS disease states in the near future.

CRISPR/Cas9-coupled recombineering for metabolic engineering of Corynebacterium glutamicum.

Genome engineering of Corynebacterium glutamicum, an important industrial microorganism for amino acids production, currently relies on random mutagenesis and inefficient double crossover events. Here we report a rapid genome engineering strategy to scarlessly knock out one or more genes in C. glutamicum in sequential and iterative manner. Recombinase RecT is used to incorporate synthetic single-stranded oligodeoxyribonucleotides into the genome and CRISPR/Cas9 to counter-select negative mutants. We completed the system by engineering the respective plasmids harboring CRISPR/Cas9 and RecT for efficient curing such that multiple gene targets can be done iteratively and final strains will be free of plasmids. To demonstrate the system, seven different mutants were constructed within two weeks to study the combinatorial deletion effects of three different genes on the production of γ-aminobutyric acid, an industrially relevant chemical of much interest. This genome engineering strategy will expedite metabolic engineering of C. glutamicum.

Computed Tomography Features of Appendiceal Metastasis in Patients With Underlying Malignancy: Comparison With Pathological Findings.

OBJECTIVE: To evaluate the computed tomography (CT) findings compared with pathologic features and to determine whether CT findings are useful for diagnosis of appendiceal metastasis in patients with underlying malignancy. MATERIALS AND METHODS: Preoperative CT examinations of 59 patients who had underlying malignancy and underwent appendectomy were evaluated. Appendiceal metastasis (n = 21) and nonmetastasis (n = 38) were pathologically confirmed. Computed tomography features (appendiceal morphology and diameter, presence of ascites, rectal shelf, omental cake, lymphadenopathy or organ metastasis) were retrospectively reviewed, and compared with histopathological findings. Fisher exact test and Wilcoxon rank sum test were performed for statistical analysis. RESULTS: Mean diameter of appendiceal metastasis was significantly larger (9.1 mm) than that of nonmetastasis (5.2 mm), (P < 0.0001). The CT morphology of appendiceal metastasis showed broad spectrum, and 3 cases of nodular thickening was only detected in appendiceal metastasis. There was a significant difference between groups (P = 0.0102). Appendiceal metastasis was more frequently associated with peritoneal seeding (ascitis, rectal shelf, omental cake) than nonmetastasis (P < 0.0001). Histopathological invasion of appendiceal metastasis was more frequently seen in serosa-mesoappendix (n = 20, 100%) or muscularis propria (n = 17, 85%), than in submucosa (n = 10, 50%) or mucosa layer (n = 7, 35%). Acute appendicitis was more commonly detected in metastasis (n = 4) than in nonmetastasis (n = 1) (P = 0.0495). CONCLUSIONS: Evaluation of CT features of appendix and peritoneum may be useful for prediction of appendiceal metastasis in patients with underlying malignancy.

Metabolic engineering of Corynebacterium glutamicum for enhanced production of 5-aminovaleric acid.

BACKGROUND: 5-Aminovaleric acid (5AVA) is an important five-carbon platform chemical that can be used for the synthesis of polymers and other chemicals of industrial interest. Enzymatic conversion of L-lysine to 5AVA has been achieved by employing lysine 2-monooxygenase encoded by the davB gene and 5-aminovaleramidase encoded by the davA gene. Additionally, a recombinant Escherichia coli strain expressing the davB and davA genes has been developed for bioconversion of L-lysine to 5AVA. To use glucose and xylose derived from lignocellulosic biomass as substrates, rather than L-lysine as a substrate, we previously examined direct fermentative production of 5AVA from glucose by metabolically engineered E. coli strains. However, the yield and productivity of 5AVA achieved by recombinant E. coli strains remain very low. Thus, Corynebacterium glutamicum, a highly efficient L-lysine producing microorganism, should be useful in the development of direct fermentative production of 5AVA using L-lysine as a precursor for 5AVA. Here, we report the development of metabolically engineered C. glutamicum strains for enhanced fermentative production of 5AVA from glucose. RESULTS: Various expression vectors containing different promoters and origins of replication were examined for optimal expression of Pseudomonas putida davB and davA genes encoding lysine 2-monooxygenase and delta-aminovaleramidase, respectively. Among them, expression of the C. glutamicum codon-optimized davA gene fused with His6-Tag at its N-Terminal and the davB gene as an operon under a strong synthetic H36 promoter (plasmid p36davAB3) in C. glutamicum enabled the most efficient production of 5AVA. Flask culture and fed-batch culture of this strain produced 6.9 and 19.7 g/L (together with 11.9 g/L glutaric acid as major byproduct) of 5AVA, respectively. Homology modeling suggested that endogenous gamma-aminobutyrate aminotransferase encoded by the gabT gene might be responsible for the conversion of 5AVA to glutaric acid in recombinant C. glutamicum. Fed-batch culture of a C. glutamicum gabT mutant-harboring p36davAB3 produced 33.1 g/L 5AVA with much reduced (2.0 g/L) production of glutaric acid. CONCLUSIONS: Corynebacterium glutamicum was successfully engineered to produce 5AVA from glucose by optimizing the expression of two key enzymes, lysine 2-monooxygenase and delta-aminovaleramidase. In addition, production of glutaric acid, a major byproduct, was significantly reduced by employing C. glutamicum gabT mutant as a host strain. The metabolically engineered C. glutamicum strains developed in this study should be useful for enhanced fermentative production of the novel C5 platform chemical 5AVA from renewable resources.

Rostral Agranular Insular Cortex Lesion with Motor Cortex Stimulation Enhances Pain Modulation Effect on Neuropathic Pain Model.

It is well known that the insular cortex is involved in the processing of painful input. The aim of this study was to evaluate the pain modulation role of the insular cortex during motor cortex stimulation (MCS). After inducing neuropathic pain (NP) rat models by the spared nerve injury method, we made a lesion on the rostral agranular insular cortex (RAIC) unilaterally and compared behaviorally determined pain threshold and latency in 2 groups: Group A (NP + MCS; n = 7) and Group B (NP + RAIC lesion + MCS; n = 7). Also, we simultaneously recorded neuronal activity (NP; n = 9) in the thalamus of the ventral posterolateral nucleus and RAIC to evaluate electrophysiological changes from MCS. The pain threshold and tolerance latency increased in Group A with "MCS on" and in Group B with or without "MCS on." Moreover, its increase in Group B with "MCS on" was more than that of Group B without MCS or of Group A, suggesting that MCS and RAIC lesioning are involved in pain modulation. Compared with the "MCS off" condition, the "MCS on" induced significant threshold changes in an electrophysiological study. Our data suggest that the RAIC has its own pain modulation effect, which is influenced by MCS.

Robotic versus laparoscopic intersphincteric resection for low rectal cancer: comparison of the operative, oncological, and functional outcomes.

BACKGROUND: Robotic surgery was developed to overcome the limitations of laparoscopic surgery and is increasingly used to treat low rectal cancer. In this study, we compared the operative, oncological, and functional outcomes of low rectal cancer patients who underwent robotic or laparoscopic intersphincteric resection (ISR). METHODS: Prospectively collected data from low rectal cancer patients who underwent laparoscopic or robotic ISR between September 2006 and August 2011 were retrospectively compared. The functional outcomes of patients followed up for ≥ 12 months after ileostomy closure were evaluated via questionnaire. RESULTS: Forty-four and 26 patients underwent robotic and laparoscopic ISR, respectively. The robotic group patients had a higher body mass index (BMI; 21.42 ± 3.13 vs. 24.13 ± 3.33 kg/m(2); p = 0.001), more advanced clinical N stage (p = 0.029), lower cancer location (3.71 ± 0.89 vs. 3.24 ± 0.78 cm; p = 0.023), more frequent chemoradiotherapy (26.9 vs. 54.5 %; p = 0.025), and longer operation time (286.77 ± 51.46 vs. 316.43 ± 65.11 min; p = 0.038). However, no intergroup differences were observed in the pathological details (except the number of retrieved lymph nodes), postoperative morbidity, 3-year overall survival, recurrence-free survival (RFS), local RFS, and functional outcomes. CONCLUSIONS: Robotic and laparoscopic ISR yielded similar operative, oncological, and functional outcomes in patients with low rectal cancer, despite differences in unfavorable outcome-affecting factors, including BMI, clinical N stage, cancer location, and chemoradiotherapy frequency. A randomized trial will provide more solid methodology for investigating the potential benefits of robotic ISR.

Impact of laparoscopic experience on virtual robotic simulator dexterity.

BACKGROUND: Different skills are required for robotic surgery and laparoscopic surgery. We hypothesized that the laparoscopic experience would not affect the performance with the da Vinci(®) system. A virtual robotic simulator was used to estimate the operator's robotic dexterity. MATERIALS AND METHODS: The performance of 11 surgical fellows with laparoscopic experience and 14 medical students were compared using the dV-trainer(®). Each subject completed three virtual endo-wrist modules ("Pick and Place," "Peg Board," and "Match Board"). Performance was recorded using a built-in scoring algorithm. RESULTS: In the Peg Board module, the performance of surgical fellows was better in terms of the number of instrument collisions and number of drops (P < 0.05). However, no significant differences were found in the percentage scores of the three endo-wrist modules between the groups. CONCLUSION: Robotic dexterity was not significantly affected by laparoscopic experience in this study. Laparoscopic experience is not an important factor for learning robotic skills.

Inertial measurement unit sensor-based gait analysis in adults and older adults: A cross-sectional study.

BACKGROUND: Gait assessment has been used in a wide range of clinical applications, and gait velocity is also a leading predictor of disease and physical functional aspects in older adults. RESEARCH QUESTION: The study aim to examine the changes in IMU-based gait parameters according to age in healthy adults aged 50 and older, to analyze differences between aging patients. METHODS: A total of 296 healthy adults (65.32 ± 6.74 yrs; 83.10 % female) were recruited. Gait assessment was performed using an IMU sensor-based gait analysis system, and 3D motion information of hip and knee joints was obtained using magnetic sensors. The basic characteristics of the study sample were stratified by age category, and the baseline characteristics between the groups were compared using analysis of variance (ANOVA). Pearson's correlation analysis was used to analyze the relationship between age as the dependent variable and several measures of gait parameters and joint angles as independent variables. RESULTS: The results of this study found that there were significant differences in gait velocity and both terminal double support in the three groups according to age, and statistically significant differences in the three groups in hip joint angle and knee joints angle. In addition, it was found that the gait velocity and knee/hip joint angle changed with age, and the gait velocity and knee/hip joint angle were also different in the elderly and adult groups. CONCLUSIONS: We found changes in gait parameters and joint angles according to age in healthy adults and older adults and confirmed the difference in gait velocity and joint angles between adults and older adults.

Computer modeling for the prediction of thoracic aortic stent graft collapse.

OBJECTIVE: To assess the biomechanical implications of excessive stent protrusion into the aortic arch in relation to thoracic aortic stent graft (TASG) collapse by simulating the structural load and quantifying the fluid dynamics on the TASG wall protrusion extended into a model arch. METHODS: One-way coupled fluid-solid interaction analyses were performed to investigate the flow-induced hemodynamic and structural loads exerted on the proximal protrusion of the TASG and aortic wall reconstructed from a patient who underwent traumatic thoracic aortic injury repair. Mechanical properties of a Gore TAG thoracic endoprosthesis (W. L. Gore and Assoc, Flagstaff, Ariz) were assessed via experimental radial compression testing and incorporated into the computational modeling. The TASG wall protrusion geometry was characterized by the protrusion extension (PE) and by the angle (θ) between the TASG and the lesser curvature of the aorta. The effect of θ was explored with the following four models with PE fixed at 1.1 cm: θ = 10 degrees, 20 degrees, 30 degrees, and 40 degrees. The effect of PE was evaluated with the following four models with θ fixed at 10 degrees: PE = 1.1 cm, 1.4 cm, 1.7 cm and 2.0 cm. RESULTS: The presence of TASG wall protrusion into the aortic arch resulted in the formation of swirling, complex flow regions in the proximal luminal surface of the endograft. High PE values (PE = 2.0 cm) led to a markedly reduced left subclavian flow rate (0.27 L/min), low systolic perfusion pressure (98 mm Hg), and peak systolic TASG diameter reduction (2 mm). The transmural pressure load across the TASG was maximum for the model with the highest PE and θ, 15.2 mm Hg for the model with PE = 2.0 cm and θ = 10 degrees, and 11.6 mm Hg for PE = 1.1 cm and θ = 40 degrees. CONCLUSIONS: The findings of this study suggest that increased PE imparts an apparent risk of distal end-organ malperfusion and proximal hypertension and that both increased PE and θ lead to a markedly increased transmural pressure across the TASG wall, a load that would portend TASG collapse. Patient-specific computational modeling may allow for identification of patients with high risk of TASG collapse and guide preventive intervention. CLINICAL RELEVANCE: A potentially devastating complication that may occur after endovascular repair of traumatic thoracicaortic injuries is stent graft collapse. Although usually asymptomatic, stent graft collapse may be accompanied by adverse hemodynamic consequences. Numerous anatomic and device-related factors contribute to the development of collapse, but predictive factors have not yet been clearly defined. In the present study, we assessed the relevant hemodynamics and solid mechanics underlying stent graft collapse using a computational fluid-structure interaction framework of stent graft malapposition. Our findings suggest that both increased stent graft angle and extension into the aortic arch lead to a markedly increased transmural pressure across the stent graft wall, portending collapse. Patient-specific computational modeling may allow for identification of patients at high risk for collapse and aid in planning for an additional, prophylactic intervention to avert its occurrence.

Selective use of preoperative chemoradiotherapy for T3 rectal cancer can be justified: analysis of local recurrence.

BACKGROUND: Preoperative chemoradiotherapy (CXRT) is performed to reduce local recurrence and improve the rate of radical resection for rectal cancer. Currently, it is recommended for all suspected T3 rectal cancers. However, the survival benefit of this procedure is controversial, and complications of RT are often overlooked. The present study was designed to assess the validity of our institutional policies regarding selective use of preoperative CXRT for T3 rectal cancer. METHODS: From September 2006 to May 2010, we retrospectively analyzed data for patients with pathologic T3 rectal cancer, especially those with follow-up for more than 18 months. Patients who underwent RT pre-/postoperatively were excluded. Patients who fulfilled these criteria but did not undergo RT or had incurable distant metastasis were also excluded. RESULTS: Of the 319 patients who underwent surgery for rectal cancer, 183 were diagnosed with T3 cancer. After excluding 58 patients, the final sample included 125 subjects with a mean follow-up of 26.0 months. In all, 94 patients had a follow-up of more than 18 months. Four patients had local recurrences, and the cumulative local recurrence rate was 3.4 % at 18 months and 5.6 % after 2 years. All four had low rectal cancer (mean distance 4.5 ± 1.9 cm). Three were diagnosed as N0 and one as N1. The mean disease-free period was 15.0 months. The distance between the tumor and the anal verge was the only significant risk factor for local recurrence. CONCLUSIONS: In this study, the oncologic outcome for T3 rectal cancer without preoperative CXRT was acceptable in terms of local recurrence. Selective use of preoperative CXRT for T3 rectal cancer needs to be further evaluated prospectively.

Factors affecting the competitiveness of bacterial fermentation.

Sustainable production of chemicals and materials from renewable non-food biomass using biorefineries has become increasingly important in an effort toward the vision of 'net zero carbon' that has recently been pledged by countries around the world. Systems metabolic engineering has allowed the efficient development of microbial strains overproducing an increasing number of chemicals and materials, some of which have been translated to industrial-scale production. Fermentation is one of the key processes determining the overall economics of bioprocesses, but has recently been attracting less research attention. In this Review, we revisit and discuss factors affecting the competitiveness of bacterial fermentation in connection to strain development by systems metabolic engineering. Future perspectives for developing efficient fermentation processes are also discussed.

Targeted and high-throughput gene knockdown in diverse bacteria using synthetic sRNAs.

Synthetic sRNAs allow knockdown of target genes at translational level, but have been restricted to a limited number of bacteria. Here, we report the development of a broad-host-range synthetic sRNA (BHR-sRNA) platform employing the RoxS scaffold and the Hfq chaperone from Bacillus subtilis. BHR-sRNA is tested in 16 bacterial species including commensal, probiotic, pathogenic, and industrial bacteria, with >50% of target gene knockdown achieved in 12 bacterial species. For medical applications, virulence factors in Staphylococcus epidermidis and Klebsiella pneumoniae are knocked down to mitigate their virulence-associated phenotypes. For metabolic engineering applications, high performance Corynebacterium glutamicum strains capable of producing valerolactam (bulk chemical) and methyl anthranilate (fine chemical) are developed by combinatorial knockdown of target genes. A genome-scale sRNA library covering 2959 C. glutamicum genes is constructed for high-throughput colorimetric screening of indigoidine (natural colorant) overproducers. The BHR-sRNA platform will expedite engineering of diverse bacteria of both industrial and medical interest.

Endovascular repair of ruptured abdominal aortic aneurysm does not confer survival benefits over open repair.

OBJECTIVE: Endovascular repair of ruptured abdominal aortic aneurysm (rAAA) is being increasingly performed despite lack of good evidence for its superiority. Other reported studies suffer from patient selection and publication bias with limited follow-up. This study is a single-center propensity score comparing early and midterm outcomes between open surgical repair (OSR) and endovascular repair of rAAA (REVAR). METHODS: A retrospective review from January 2001 to November 2010 identified 312 patients who underwent rAAA repairs. Thirty-one patients with antecedent AAA repair and three with incomplete records were excluded, leaving 37 REVARs and 241 OSRs. Propensity score-based matching for sex, age, preoperative hemodynamic status, surgeon's annual AAA volume, and preoperative cardiopulmonary resuscitation was performed in a 1:3 ratio to compare outcomes. Thirty-seven REVARs were matched with 111 OSRs. Late survival was estimated by Kaplan-Meier methods. RESULTS: Operative time and blood replacement were higher with OSR. Overall complication rates were similar (54% REVAR vs 66% OSR; P = .23), except for higher incidences of tracheostomies (21% vs 3%; P = .015), myocardial infarction (38% vs 18%; P = .036), and acute tubular necrosis (47% vs 21%; P = .009) with OSR. Operative mortality rates were similar (22% REVAR vs 32% OSR), with an odds ratio of 0.63 for REVAR (95% confidence interval = [0.24, 1.48]; P = .40). No differences in the incidences for secondary interventions for aneurysm- or graft-related complications were noted (22% REVAR vs 22% OSR; P = .99). Kaplan-Meier estimates of 1-, 2-, and 3-year survival rates were also similar (50%, 50%, 42% REVAR vs 54%, 52%, 47% OSR; P = .66). CONCLUSIONS: REVAR for rAAA does not seem to conclusively confer either acute or late survival advantages. Routine use of REVAR should be deferred until prospective, randomized trial data become available.

Delayed open conversions after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Secondary interventions after endovascular aneurysm repair (EVAR) remain a concern. Most are simple catheter-based procedures, but in some instances, open conversions (OCs) are required and carry a worse outcome. We reviewed our experience to characterize these OCs. METHODS: A retrospective review was conducted of all patients who underwent an OC after a previous EVAR for an aneurysm-related indication from 2001 to 2010. Clinical outcomes are reported. RESULTS: Data were reviewed for 44 patients (77% men) with a mean age of 74 years (range, 55-90 years). The average time from EVAR to the first OC was 45 months (range, 2-190 months). In six patients (14%), the initial EVAR was at another institution. The endografts used were Ancure in 16, Excluder in 13, AneuRx in eight, Zenith in three, Lifepath in one, Renu in one, and undetermined in two. Twenty-two patients had previously undergone a total of 32 endovascular reinterventions before their index OC. Indications for OC were aneurysm expansion in 28 (64%), rupture in 12 (27%), and infection in four (9%). The endograft was preserved in situ in 10 patients (23%). Explantation was partial in 18 (41%) or complete in 16 (36%). Endograft preservation was used for type II endoleak in all but one patient by selective ligation of the culprit arteries (lumbar in four, inferior mesenteric artery in five, and middle sacral in one). Proximal neck banding was performed in one type Ia endoleak. Overall morbidity was 55%, and mortality was 18%. No deaths occurred in a subgroup of patients who underwent endograft preservation with selective ligation of culprit vessels for type II endoleak. Intraoperative complications included bowel injury in two, bleeding in two, splenectomy in one, and ureteral injury in one. At a mean follow-up of 20 months, two patients underwent additional procedures after the index OC: one after endograft preservation and one after partial explantation. None of the patients who underwent elective OC with endograft preservation required subsequent endograft explantation. CONCLUSIONS: Most OCs after EVAR are associated with significant morbidity and mortality, except when electively treating an isolated type II endoleak with ligation of branches and preservation of the endograft.