Reduction of hemagglutination induced by a SARS-CoV-2 spike protein fragment using an amyloid-binding benzothiazole amphiphile.

COVID-19 infection is associated with a variety of vascular occlusive morbidities. However, a comprehensive understanding of how this virus can induce vascular complications remains lacking. Here, we show that a peptide fragment of SARS-CoV-2 spike protein, S192 (sequence 192-211), is capable of forming amyloid-like aggregates that can induce agglutination of red blood cells, which was not observed with low- and non-aggregated S192 peptide. We subsequently screened eight amyloid-binding molecules and identified BAM1-EG6, a benzothiazole amphiphile, as a promising candidate capable of binding to aggregated S192 and partially inhibiting its agglutination activity. These results provide new insight into a potential molecular mechanism for the capability of spike protein metabolites to contribute to COVID-19-related blood complications and suggest a new therapeutic approach for combating microvascular morbidities in COVID-19 patients.

Excited State Rotational Freedom Impacts Viscosity Sensitivity in Arylcyanoamide Fluorescent Molecular Rotor Dyes.

The microviscosity of intracellular environments plays an important role in monitoring cellular function. Thus, the capability of detecting changes in viscosity can be utilized for the detection of different disease states. Viscosity-sensitive fluorescent molecular rotors are potentially excellent probes for these applications; however, the predictable relationships between chemical structural features and viscosity sensitivity are poorly understood. Here, we investigate a set of arylcyanoamide-based fluorescent probes and the effect of small aliphatic substituents on their viscosity sensitivity. We found that the location of the substituents and the type of π-network of the fluorophore can significantly affect the viscosity sensitivity of these fluorophores. Computational analysis supported the notion that the excited state rotational energy barrier plays a dominant role in the relative viscosity sensitivity of these fluorophores. These findings provide valuable insight into the design of molecular rotor-based fluorophores for viscosity measurement.

Clinical characteristics and outcomes of obstetric patients transferred directly to intensive care units.

BACKGROUND: Medical complications in peripartum patients are uncommon. Often, these patients are transferred to tertiary care centers, but their conditions and outcomes are not well understood. Our study examined peripartum patients transferred to an intensive care unit (ICU) at an academic quaternary center. METHODS: We reviewed charts of adult, non-trauma, interhospital transfer (IHT) peripartum patients sent to an academic quaternary ICU between January 2017 and December 2021. We conducted a descriptive analysis and used multivariable ordinal regression to examine associations of demographic and clinical factors with ICU length of stay (LOS) and hospital length of stay (HLOS). RESULTS: Of 1,794 IHT peripartum patients, 60 (3.2%) were directly transferred to an ICU. The average was 32 years, with a median Sequential Organ Failure Assessment (SOFA) score of 3 (1-4.25) and Acute Physiology and Chronic Health Evaluation (APACHE) II score of 8 (7-12). Respiratory failure was most common (32%), followed by postpartum hemorrhage (15%) and sepsis (14%). Intubation was required for 24 (41%), and 4 (7%) needed extracorporeal membrane oxygenation. Only 1 (1.7%) died, while 45 (76.3%) were discharged. Median ICU LOS and HLOS were 5 days (212) and 8 days (5-17). High SOFA score was linked to longer HLOS, as was APACHE II. CONCLUSIONS: Transfers of critically ill peripartum patients between hospitals were rare but involved severe medical conditions. Despite this, their outcomes were generally positive. Larger studies are needed to confirm our findings.

Binding and Activation of LRP1-Dependent Cell Signaling in Schwann Cells Using a Peptide Derived from the Hemopexin Domain of MMP-9.

Schwann cells (SCs) undergo phenotypic transformation and then orchestrate nerve repair following a peripheral nervous system injury. The low-density lipoprotein receptor-related protein-1 (LRP1) is significantly upregulated in SCs in response to acute injury, activating cJun and promoting SC survival. Matrix-metalloproteinase-9 (MMP-9) is an LRP1 ligand that binds LRP1 through its hemopexin domain (PEX) and activates SC survival signaling and migration. To identify novel peptide mimetics within the hemopexin domain of MMP-9, we examined the crystal structure of PEX, synthesized four peptides, and examined their potential to bind and activate LRP1. We demonstrate that a 22 amino acid peptide, peptide 2, was the only peptide that activated Akt and ERK1/2 signaling in SCs, similar to a glutathione s-transferase (GST)-fused holoprotein, GST-PEX. Intraneural injection of peptide 2, but not vehicle, into crush-injured sciatic nerves activated cJun greater than 2.5-fold in wild-type mice, supporting that peptide 2 can activate the SC repair signaling in vivo. Peptide 2 also bound to Fc-fusion proteins containing the ligand-binding motifs of LRP1, clusters of complement-like repeats (CCRII and CCRIV). Pulldown and computational studies of alanine mutants of peptide 2 showed that positively charged lysine and arginine amino acids within the peptide are critical for stability and binding to CCRII. Collectively, these studies demonstrate that a novel peptide derived from PEX can serve as an LRP1 agonist and possesses qualities previously associated with LRP1 binding and SC signaling in vitro and in vivo.

Abdominal donor-site complications following autologous breast reconstruction: A multi-institutional multisurgeon study.

BACKGROUND: The deep inferior epigastric perforator (DIEP) free flap is the gold standard procedure for autologous breast reconstruction. Although breast-related complications have been well described, donor-site complications and contributing patient risk factors are poorly understood. METHODS: We examined a multi-institutional, prospectively maintained database of patients undergoing DIEP free flap breast reconstruction between 2015 and 2020. We evaluated patient demographics, operative details, and abdominal donor-site complications. Logistic regression modeling was used to predict donor-site outcomes based on patient characteristics. RESULTS: A total of 661 patients were identified who underwent DIEP free flap breast reconstruction across multiple institutions. Using logistic regression modeling, we found that body mass index (BMI) was an independent risk factor for umbilical complications (odds ratio [OR] 1.11, confidence interval [CI] 1.04-1.18, p = 0.001), seroma (OR 1.07, CI 1.01-1.13, p = 0.003), wound dehiscence (OR 1.10, CI 1.06-1.15, p = 0.001), and surgical site infection (OR 1.10, CI 1.05-1.15, p = 0.001) following DIEP free flap breast reconstruction. Further, immediate reconstruction decreases the risk of abdominal bulge formation (OR 0.22, CI 0.108-0.429, p = 0.001). Perforator selection was not associated with abdominal morbidity in our study population. CONCLUSIONS: Higher BMI is associated with increased abdominal donor-site complications following DIEP free flap breast reconstruction. Efforts to lower preoperative BMI may help decrease donor-site complications.

Approximate Policy Iteration With Deep Minimax Average Bellman Error Minimization.

In this work, we investigate the utilization of deep approximate policy iteration (DAPI) in estimating the optimal action-value function Q* within the context of reinforcement learning, employing rectified linear unit (ReLU) ResNet as the underlying framework. The iterative process of DAPI incorporates the minimax average Bellman error minimization principle. It employs ReLU ResNet to estimate the fixed point of the Bellman equation, which is aligned with the estimated greedy policy. Through error propagation, we derive nonasymptotic error bounds between Q* and the estimated Q function induced by the output greedy policy in DAPI. To effectively control the Bellman residual error, we address both the statistical and approximation errors associated with the α -mixing dependent data derived from Markov decision processes, using the techniques of empirical process and deep approximation theory, respectively. Furthermore, we present a novel generalization bound for ReLU ResNet in the presence of dependent data, as well as an approximation bound for ReLU ResNet within the Hölder class. Notably, this approximation bound contributes to a significant improvement in the dependence on the ambient dimension, transitioning from an exponential relationship to a polynomial one. The derived nonasymptotic error bounds explicitly depend on factors such as the sample size, the ambient dimension (in polynomial terms), and the width and depth of the neural networks. Consequently, these bounds serve as valuable theoretical guidelines for appropriately setting the hyperparameters, thereby enabling the achievement of the desired convergence rate during the training process of DAPI.

Antivesiculation and Complete Unbinding of Tail-Tethered Lipids.

We report the effect of tail-tethering on vesiculation and complete unbinding of bilayered membranes. Amphiphilic molecules of a bolalipid, resembling the tail-tethered molecular structure of archaeal lipids, with two identical zwitterionic phosphatidylcholine headgroups self-assemble into a large flat lamellar membrane, in contrast to the multilamellar vesicles (MLVs) observed in its counterpart, monopolar nontethered zwitterionic lipids. The antivesiculation is confirmed by small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cyro-TEM). With the net charge of zero and higher bending rigidity of the membrane (confirmed by neutron spin echo (NSE) spectroscopy), the current membrane theory would predict that membranes should stack with each other (aka "bind") due to dominant van der Waals attraction, while the outcome of the nonstacking ("unbinding") membrane suggests that the theory needs to include entropic contribution for the nonvesicular structures. This report pioneers an understanding of how the tail-tethering of amphiphiles affects the structure, enabling better control over the final nanoscale morphology.

Machine-Learning Identifies a Strategy for Differentiation Therapy in Solid Tumors.

BACKGROUND: Although differentiation therapy can cure some hematologic malignancies, its curative potential remains unrealized in solid tumors. This is because conventional computational approaches succumb to the thunderous noise of inter-/intratumoral heterogeneity. Using colorectal cancers (CRCs) as an example, here we outline a machine learning(ML)-based approach to track, differentiate, and selectively target cancer stem cells (CSCs). METHODS: A transcriptomic network was built and validated using healthy colon and CRC tissues in diverse gene expression datasets (~5,000 human and >300 mouse samples). Therapeutic targets and perturbation strategies were prioritized using ML, with the goal of reinstating the expression of a transcriptional identifier of the differentiated colonocyte, CDX2, whose loss in poorly differentiated (CSC-enriched) CRCs doubles the risk of relapse/death. The top candidate target was then engaged with a clinical-grade drug and tested on 3 models: CRC lines in vitro, xenografts in mice, and in a prospective cohort of healthy (n = 3) and CRC (n = 23) patient-derived organoids (PDOs). RESULTS: The drug shifts the network predictably, induces CDX2 and crypt differentiation, and shows cytotoxicity in all 3 models, with a high degree of selectivity towards all CDX2-negative cell lines, xenotransplants, and PDOs. The potential for effective pairing of therapeutic efficacy (IC50) and biomarker (CDX2-low state) is confirmed in PDOs using multivariate analyses. A 50-gene signature of therapeutic response is derived and tested on 9 independent cohorts (~1700 CRCs), revealing the impact of CDX2-reinstatement therapy could translate into a ~50% reduction in the risk of mortality/recurrence. CONCLUSIONS: Findings not only validate the precision of the ML approach in targeting CSCs, and objectively assess its impact on clinical outcome, but also exemplify the use of ML in yielding clinical directive information for enhancing personalized medicine.

Direct Discharge from the Critical Care Resuscitation Unit: Results from a Longitudinal Assessment.

Background: The critical care resuscitation unit (CCRU) facilitates interhospital transfer (IHT) of critically ill patients for immediate interventions. Due to these patients' acuity, it is uncommon for patients to be directly discharged home from this unit, but it does happen on occasion. Since there is no literature regarding outcomes of patients being discharged from a resuscitation unit, our study investigated these patients' outcome at greater than 12 months after being discharged directly from the CCRU. Methods: We performed a retrospective cohort study of all adult patients directly discharged from the CCRU between January 01, 2017, and December 31, 2020. The primary outcome was number of ED visits or hospitalizations within 6 months. Secondary outcomes were number of ED visits or hospitalizations within 6, 12, and >12 months from CCRU discharge. Results: We analyzed 145 patients' records. Mean age was 56 (standard deviation [SD] ± 19), with a majority being male (72%) and Caucasian (58%). The most common discharge destination was home (139 patients, 96% of total subjects) versus hospice (2%) or nursing facilities (2%). Most patients (55%) did not have any hospital revisits within the first 6 months of discharge, while 31% had 1-2 revisits, and 14% had ≥3 revisits. The most common discharge diagnoses were soft tissue infection (16.5%), aortic dissection (14%), and stroke (11%). Factors which were associated with a greater likelihood of any return hospital visit within 6 months receiving mechanical ventilation during CCRU stay (coefficient -2.23, 95% CI 0.01-0.87, P=0.036), while high hemoglobin on CCRU discharge was associated with no ED revisit (coeff. 0.42, 95% CI 1.15-2.06, P=0.004). Conclusions: Most patients who were discharged from the CCRU did not require any hospital revisits in the first 6 months. Requiring mechanical ventilation and having soft tissue infection were associated with high unplanned hospital revisits following discharge. Further research is needed to validate these findings.

Are Diagnostic Delays Associated with Distress in Breast Cancer Patients?

Introduction: Receiving a new breast cancer diagnosis can cause anxiety and distress, which can lead to psychologic morbidity, decreased treatment adherence, and worse clinical outcomes. Understanding sources of distress is crucial in providing comprehensive care. This study aims to evaluate the relationship between delays in breast cancer diagnosis and patient-reported distress. Secondary outcomes include assessing patient characteristics associated with delay. Methods: Newly diagnosed breast cancer patients who completed a distress screening tool at their initial evaluation at an academic institution between 2014 and 2019 were retrospectively evaluated. The tool captured distress levels in the emotional, social, health, and practical domains with scores of "high distress" defined by current clinical practice guidelines. Delay from mammogram to biopsy, whether diagnostic or screening mammogram, was defined as >30 days. Result: 745 newly diagnosed breast cancer patients met inclusion criteria. Median time from abnormal mammogram to core biopsy was 12 days, and 11% of patients experienced a delay in diagnosis. The non-delayed group had higher emotional (p = 0.04) and health (p = 0.03) distress than the delayed group. No statistically significant differences in social distress were found between groups. Additionally, patients with higher practical distress had longer time interval between mammogram and surgical intervention compared to those with lower practical distress. Older age, diagnoses of invasive lobular carcinoma or ductal carcinoma in situ, and clinical anatomic stages 0-I were associated with diagnostic delay. Conclusion: Patients with higher emotional or health-related distress were more likely to have timely diagnoses of breast cancer, suggesting that patients with higher distress may seek healthcare interventions more promptly. Improved understanding of sources of distress will permit early intervention regarding the devastating impact of breast cancer diagnosis.

Venous Thromboembolism after Deep Inferior Epigastric Perforator Flap Breast Reconstruction: Review of Outcomes After a Postoperative Prophylaxis Protocol.

BACKGROUND: Deep inferior epigastric perforator (DIEP) flap breast reconstruction is among the higher-risk patient groups for venous thromboembolism (VTE) in plastic surgery. Surgeons often opt for a patient-specific approach to postoperative anticoagulation, and the field has yet to come to a consensus on VTE chemoprophylaxis regimens. METHODS: A new chemoprophylaxis protocol was introduced starting March 2019 that involved two weeks of treatment with enoxaparin, regardless of patient risk factors. A retrospective chart review was conducted on all patients who underwent DIEP flap breast reconstruction at our institution between January 2014 and March 2020. Patients were grouped based on whether they enrolled in the new VTE protocol in the postoperative period or not. Patient demographics, prophylaxis type, and outcomes data were recorded, retrospectively. The primary outcome measure was postoperative VTE incidence. RESULTS: Risk of VTE was significantly higher in patients discharged without VTE prophylaxis compared to patients discharged with prophylaxis (3.7% vs. 0%, p = 0.03). Notably, zero patients in the VTE prophylaxis group developed a DVT or PE. Additionally, the risk of a VTE event was 25 times greater in patients with a Caprini score greater than or equal to 6 (p=0.0002). CONCLUSIONS: We demonstrate the successful implementation of a two-week VTE chemoprophylaxis protocol in DIEP flap breast reconstruction patients that significantly reduces the rate of VTE while not affecting the rate of hematoma complications.

A Rare Case of Traumatic Acute Pronator Syndrome in the Setting of Anticoagulation Therapy.

Pronator syndrome (PS) is a rare type of peripheral compression neuropathy in which the median nerve becomes entrapped as it passes through the pronator teres muscle at the proximal forearm. We report an unusual case of acute PS in a 78-year-old patient on warfarin who presented after traumatic forearm injury with forearm swelling, pain, and paresthesias. After emergent nerve decompression and hematoma evacuation, the patient regained near complete recovery of median nerve function six months after diagnosis and treatment.

Synthesis of functionalized 2,3-diaminopropionates and their potential for directed monobactam biosynthesis.

The N-sulfonated monobactams harbor considerable potential to combat emerging bacterial infections that are problematic to treat due to their metallo-ß-lactamase mediated resistance against conventional ß-lactam antibiotics. Herein, we report a divergent synthesis of C3-substituted 2,3-diaminopropionates featuring an array of small functional groups and examine their potential as alternative precursors during monobactam biosynthesis in a mutant strain (ΔsulG) of Pseudomonas acidophila that is deficient in the supply of this native precursor. In vitro assays revealed high diastereoselectivity, as well as a substrate tolerance by the terminal adenylation domain of the non-ribosomal peptide synthetase (NRPS) SulM toward the majority of synthetic analogs. Chemical complementation of this mutant yielded a fluorinated, bioactive monobactam through fermentation as confirmed by a combination of spectrometric data and microbiological assays. This study demonstrates site-specific functionalization of a clinically important natural product and sets in place a platform for further strain improvements and engineered NRPS-biosynthesis of non-native congeners.

Cyclobenzaprine utilization for musculoskeletal back pain: Analysis of 2007-2019 National Hospital Ambulatory Medical Care Survey Data.

BACKGROUND: With musculoskeletal back pain being one of the most common presentations in the emergency department, evidence-based management strategies are needed to address such complaints. Along with other medications, cyclobenzaprine is a muscle relaxant commonly prescribed for patients complaining of musculoskeletal pain, in particular, pain associated with muscle spasms. However, with recent literature questioning its efficacy, the role of cyclobenzaprine use in patients with musculoskeletal back pain remains unclear. OBJECTIVES: The objective of the study is to investigate trends of cyclobenzaprine utilization among patients presenting to the emergency department (ED) in the United States. METHODS: This is a retrospective cohort review of data obtained from the National Hospital Ambulatory Medical Care Survey (NHAMCS) between 2007 and 2019. We analyzed ED visits of patients 18 years and older. Visits during which cyclobenzaprine was administered in the ED or prescribed at discharge were identified. Trends were described using a time series analysis of patients' visits who received administration and prescriptions of cyclobenzaprine. RESULTS: Between 2007 and 2019, we identified an estimated 1.35 billion ED visits, 57.2% (772.6 million) were female. From that sample, 2.4% (32.7 million) of all visits received cyclobenzaprine prescription in the ED only, and 0.5% (6.6 million) of total visits were both given the drug in the ED and were prescribed the drug at discharge). Overall trend analysis shows a slight decrease in annual percentages of cyclobenzaprine administration and prescriptions during the study period. Visits of certain subgroups: 26-44 years, white showed relatively higher percentages of administration and prescription of cyclobenzaprine. CONCLUSIONS: Although there was a slight decrease, our study still shows significant cyclobenzaprine utilization in the ED, despite conflicting evidence demonstrating efficacy for patients with musculoskeletal complaints and the concern for adverse effects. Additional studies are needed to examine its overall effectiveness and risk-benefit analysis in treating patients with such conditions.

Breast Reconstruction Trends in the Setting of Postmastectomy Radiation Therapy: Analysis of Practices among Plastic Surgeons in the United States.

Radiation is an integral part of breast cancer therapy. The ideal type and timing of breast reconstruction with relation to radiation delivery are not well established. The study aimed to identify reconstructive practices among American plastic surgeons in the setting of pre- and postmastectomy radiation. Methods: A cross-sectional survey of members of the American Society of Plastic Surgery was performed. Practice/demographic information and breast reconstruction protocols were queried. Univariate descriptive statistics were calculated, and outcomes were compared across cohorts with χ2 and Fischer exact tests. Results: Overall, 477 plastic surgeons averaging 16.3 years in practice were surveyed. With respect to types of reconstruction, all options were well represented, although nearly 60% preferred autologous reconstruction with prior radiation and 55% preferred tissue expansion followed by implant/autologous reconstruction in the setting of unknown postoperative radiation. There was little consensus on the optimal timing of reconstruction in the setting of possible postoperative radiation. Most respondents wait 4-6 or 7-12 months between the end of radiation and stage 2 implant-based or autologous reconstruction. Common concerns regarding the effect of radiation on reconstructive outcomes included mastectomy flap necrosis, wound dehiscence, capsular contracture, tissue fibrosis, and donor vessel complications. Conclusions: Despite considerable research, there is little consensus on the ideal type and timing of reconstruction in the setting of pre- and postoperative radiation. Understanding how the current body of knowledge is translated into clinical practice by different populations of surgeons allows us to forge a path forward toward more robust, evidence-based guidelines for patient care.

Extended Venous Thromboembolism Chemoprophylaxis following Microsurgical Breast Reconstruction: Analysis of Trends in Postoperative Anticoagulation.

BACKGROUND: Microsurgical breast reconstruction following mastectomy represents a high-risk patient group for venous thromboembolism (VTE), but there is limited consensus on postoperative prophylaxis duration. The aim of this study was to characterize the risk of VTE after microsurgical breast reconstruction, the risk reduction associated with postoperative outpatient VTE prophylaxis, the clinical factors associated with VTE events, and surgeon prescribing patterns regarding outpatient VTE prophylaxis. METHODS: A commercially available database of 53 million unique patients, PearlDiver, was used to identify patients with breast cancer who underwent microsurgical breast reconstruction. Patients were grouped into those receiving any form of outpatient VTE prophylaxis at discharge and those who did not. Probability of VTE within 90 days was calculated for each group followed by absolute risk reduction and number needed to treat. A logistic regression, assuming binomial distribution, was performed to determine clinical factors associated with VTE events after surgery. RESULTS: A total of 22,606 patients underwent microsurgical breast reconstruction from 2010 to 2020. Of these patients, 356 (1.6%) were discharged with VTE prophylaxis and 22,250 (98.4%) were discharged without. No patients developed a VTE in the prophylaxis group, and 403 (1.8%) developed a VTE in the group without prophylaxis. The number needed to prevent one VTE was 55.25 patients. Most VTE events occurred after postoperative day 10 (71.3%). CONCLUSIONS: Outpatient chemoprophylaxis following breast reconstruction is underused despite the majority of VTE events occurring after the acute postoperative period. Breast microsurgeons should consider routine outpatient chemoprophylaxis as part of their postoperative care pathway to optimize VTE prevention. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Development of fluorophores for the detection of oligomeric aggregates of amyloidogenic proteins found in neurodegenerative diseases.

Alzheimer's disease and Parkinson's disease are the two most common neurodegenerative diseases globally. These neurodegenerative diseases have characteristic late-stage symptoms allowing for differential diagnosis; however, they both share the presence of misfolded protein aggregates which appear years before clinical manifestation. Historically, research has focused on the detection of higher-ordered aggregates (or amyloids); however, recent evidence has shown that the oligomeric state of these protein aggregates plays a greater role in disease pathology, resulting in increased efforts to detect oligomers to aid in disease diagnosis. In this review, we summarize some of the exciting new developments towards the development of fluorescent probes that can detect oligomeric aggregates of amyloidogenic proteins present in Alzheimer's and Parkinson's disease patients.

Site-Specific C-Terminal Fluorescent Labeling of Tau Protein.

Formation of Tau protein aggregates in neurons is a pathological hallmark of several neurodegenerative diseases, including Alzheimer's disease. Fluorescently labeled Tau protein is therefore useful to study the aggregation of these pathological proteins and to identify potential therapeutic targets. Conventionally, cysteine residues are used for labeling Tau proteins; however, the full-length Tau isoform contains two cysteine residues in the microtubule-binding region, which are implicated in Tau aggregation by forming intermolecular disulfide bonds. To prevent the fluorescent label from disturbing the microtubule binding region, we developed a strategy to fluorescently label Tau at its C-terminus while leaving cysteine residues unperturbed. We took advantage of a Sortase A-mediated transpeptidation approach to bind a short peptide (GGGH6-Alexa647) with a His-tag and a covalently attached Alexa 647 fluorophore to the C-terminus of Tau. This reaction relies on the presence of a Sortase recognition motif (LPXTG), which we attached to the C-terminus of recombinantly expressed Tau. We demonstrate that C-terminal modification of Tau protein results in no significant differences between the native and C-terminally labeled Tau monomer with regard to aggregation kinetics, secondary structure, and fibril morphology.

Teachers' Language Use in Multilingual Head Start Classrooms: Implications for Dual Language Learners.

Dual language learners (DLLs) are sensitive to teachers' language influence in early childhood classrooms. In this mixed methods study incorporating 53 teachers from 28 preschools in Northern California, we investigated the characteristics of teachers' language use in preschools teaching Chinese-English and Spanish-English DLLs. We further examined the links of teachers' language use to the DLLs' expressive vocabulary in English and their heritage language (HL), controlling for home language exposure and other confounding variables. Finally, we conducted interviews with teachers to understand how they make meaning of their daily language practices. The sample of children consisted of 190 Chinese-English (N = 125) and Spanish-English (N = 65) DLLs (mean age = 48.3 months; 48% females). The teacher survey showed that most teachers spoke two or more languages and used a mix of English and their HL during their interactions with DLLs. The results of random-intercept models showed that teachers' language use did not uniquely predict children's vocabulary, controlling for family-level factors. However, the teachers with more years of teaching DLLs oversaw children with a higher HL vocabulary. The interview data revealed that teachers employ several strategies to communicate with DLLs and support HL maintenance. Our study reveals the multilingual backgrounds of preschool teachers and the rich language strategies they implement in multilingual classrooms. Future directions concerning the quality and development of teachers' language use are discussed.

Multidisciplinary Treatment of Persistent Nontuberculous Mycobacterial Spinal Hardware Infection with a Pedicled Superior Gluteal Artery Perforator Flap.

Nontuberculous mycobacterial hardware infections are extremely challenging to treat. Multidisciplinary care involving removal of infected hardware, thorough debridement, and durable soft tissue coverage in conjunction with antibiotic therapy is essential for successful management. This case report presents a patient with chronic mycobacterial spinal hardware infection that underwent successful treatment with aggressive serial debridements and reconstruction with a large pedicled superior gluteal artery perforator flap coverage.