Ready-to-use iPSC-derived microglia progenitors for the treatment of CNS disease in mouse models of neuropathic mucopolysaccharidoses.

Mucopolysaccharidoses are inherited metabolic disorders caused by the deficiency in lysosomal enzymes required to break down glycosaminoglycans. Accumulation of glycosaminoglycans leads to progressive, systemic degenerative disease. The central nervous system is particularly affected, resulting in developmental delays, neurological regression, and early mortality. Current treatments fail to adequately address neurological defects. Here we explore the potential of human induced pluripotent stem cell (hiPSC)-derived microglia progenitors as a one-time, allogeneic off-the-shelf cell therapy for several mucopolysaccharidoses (MPS). We show that hiPSC-derived microglia progenitors, possessing normal levels of lysosomal enzymes, can deliver functional enzymes into four subtypes of MPS knockout cell lines through mannose-6-phosphate receptor-mediated endocytosis in vitro. Additionally, our findings indicate that a single administration of hiPSC-derived microglia progenitors can reduce toxic glycosaminoglycan accumulation and prevent behavioral deficits in two different animal models of MPS. Durable efficacy is observed for eight months after transplantation. These results suggest a potential avenue for treating MPS with hiPSC-derived microglia progenitors.

Advances in HIV Management During Pregnancy and Infant Feeding.

Recent advances in human immunodeficiency virus (HIV) management during pregnancy and infant feeding encompass several key elements: expanded HIV testing guidance; growing evidence of safety, efficacy, and pharmacokinetic data favoring the use of preferred antiretroviral therapy (ART) during pregnancy and breastfeeding; increasing advocacy for the inclusion of pregnant individuals with HIV in clinical trials to expedite access to new ART; and updated guidelines supporting shared decision-making for choice of infant feeding methods in people with HIV.

Clinical Trials That Have Changed Clinical Practice and Care of Pregnant People With HIV.

Over the last 4 decades, significant advances in the care of HIV during pregnancy have successfully reduced, and nearly eliminated, the risk of perinatal HIV transmission. The baseline risk of transmission without intervention (25% to 30%) is now <1% to 2% in the United States with contemporary antepartum, intrapartum, and postnatal interventions. In this review, we discuss 3 landmark clinical trials that substantially altered obstetric practice for pregnant individuals with HIV and contributed to this extraordinary achievement: 1) the Pediatric AIDS Clinical Trials Group 076 Trial determined that antepartum and intrapartum administration of antiretroviral drug zidovudine to the pregnant individual, and postnatally to the newborn, could reduce the risk of perinatal transmission by approximately two-thirds; 2) the European Mode of Delivery Collaboration Trial demonstrated performance of a prelabor cesarean birth before rupture of membranes among pregnant people with viremia reduced the risk of perinatal transmission compared with vaginal birth; and 3) the International Maternal Pediatric Adolescent AIDS Clinical Trials Network 2010 Trial identified that dolutegravir-containing, compared with efavirenz-containing, antiretroviral regimens during pregnancy achieved a significantly higher rate of viral suppression at delivery with shorter time to viral suppression, with fewer adverse pregnancy outcomes. Collectively, these trials not only advanced obstetric practice but also advanced scientific understanding of the timing, mechanisms, and determinants of perinatal HIV transmission. For each trial, we will describe key aspects of the study protocol and outcomes, insights gleaned about the dynamics of perinatal transmission, how each study changed clinical practice, and relevant updates to current practice since the trial's publication.

Association of Fatty Acid Signatures with HIV Viremia in Pregnancy.

Omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) are vital for fetal metabolic programming and immunomodulation. Higher n-6:n-3 ratios, reflecting a proinflammatory eicosanoid profile, are associated with adverse perinatal outcomes. Limited data exist, however, on n-6 and n-3 PUFAs specifically in the context of HIV and pregnancy. Our objective was to assess HIV clinical factors associated with PUFA signatures in pregnant persons with HIV (PWH). In this observational cohort, third trimester plasma PUFA concentrations (six n-6 PUFAs, four n-3 PUFAs) were measured, each as a percent of total fatty acid content, via esterification and gas chromatography in pregnant PWH enrolled from 2009 to 2011 in the Nutrition substudy of the Pediatric HIV/AIDS Cohort Study. PUFA ratios (n-6:n-3) were calculated. Exposures assessed were first/second trimester CD4 count (<200 vs. >200 cells/mm3), HIV RNA viral load (VL) (VL >400 vs. <400 copies/mL), and protease inhibitor (PI) versus non-PI antiretroviral therapy (ART). Linear regression models using generalized estimating equations were fit to assess mean differences and their 95% confidence intervals (CIs) in n-6:n-3 by each exposure, adjusted for potential confounders. Of 264 eligible pregnant PWH, the median age was 27 years, 12% had CD4 counts <200 cells/mm3, and 56% had VL ≥400 copies/mL in the first/second trimesters. PUFA concentrations and ratios were similar by CD4 count and PI exposure. n-3 concentrations were lower in PWH with VL ≥400 versus <400 copies/mL (median 2.8% vs. 3.0%, p < .01, respectively); no differences were observed for n-6 concentrations by VL. In models adjusted for age, education, tobacco use, body mass index, and PI-based ART, n-6:n-3 was higher in those with VL ≥400 copies/mL (mean difference: 1.6; 95% CI: 0.79-2.48, p = .0001). Therefore, PUFA signatures in viremic pregnant PWH reflect a proinflammatory eicosanoid milieu. Future studies should evaluate associations of proinflammatory PUFA signatures with adverse perinatal outcomes in PWH.

Safety and Efficiency Outcomes of Ambulatory Gynaecologic Procedures in Canadian Surgical Centres Adopting a Common Model.

OBJECTIVE: The present study aims to compare the safety and efficiency outcomes of ambulatory gynaecologic procedures performed under conscious sedation and/or local anaesthetic at 2 Canadian institutions. METHODS: A retrospective cohort study was completed over 1-year on patients presenting to the ambulatory care centres at 2 Canadian institutions that shared a common care model. Outcomes of interest were lead time (registration to discharge), procedural time, and intraoperative complications. Surgical data was derived from a retrospective chart review and outcomes were compared using the independent t test and one-way analysis of variance. RESULTS: A total of 1495 and 1098 patients presented to the 2 sites. The average age of patients was 35.5 ± 12.3 years and 41.7 ± 10.2 years. The most commonly performed procedures were dilatation and curettages at the first centre and operative hysteroscopies at the second centre. Average lead times were similar: 170.3 ± 35.8 minutes and 171.6 ± 45.4 minutes (P = 0.45). There was a significant difference in mean procedural time being 9.8 ± 5.5 minutes and 17.0 ± 10.0 minutes (P < 0.001). The rate of minor intraoperative complications was 3.8% and 6.6% (P = 0.002); whereas the rate of major complications was 2.7% and 3.3% (P = 0.43). CONCLUSION: In Canada, the majority of gynaecologic procedures are performed under general anesthesia. By comparing outcomes at 2 separate Canadian centres, we demonstrated the reproducibility of a common ambulatory model for minor gynaecologic procedures, supporting the implementation of similar care models across Canada.

Continuous Subcutaneous Infusion Versus Multiple Daily Injections of Insulin for Pregestational Diabetes in Pregnancy: A Systematic Review and Meta-Analysis.

BACKGROUND: The use of continuous subcutaneous insulin infusion (CSII) therapy in pregnancies affected by pregestational diabetes mellitus (DM) has generated mixed outcome data worthy of further investigation. This systematic review and meta-analysis aims to evaluate clinical outcomes associated with CSII versus multiple daily injections (MDIs) in pregnant persons with pregestational DM. METHODS: A predefined, systematic, librarian-assisted search of MEDLINE (PubMed), Embase, Cochrane Library, Scopus, ClinicalTrials.gov, and World Health Organization International Clinical Trial Registry Platform (published from 2010 to 2022) yielded 3003 studies describing pregnancy outcomes associated with CSII and/or MDI for pregestational DM. The primary exposure was mode of insulin administration, with cesarean delivery and neonatal hypoglycemia as the primary maternal and neonatal outcomes, respectively. Secondary outcomes included hypertensive disorders of pregnancy, first and third-trimester glycemic control, large-for-gestational age (LGA) neonate, preterm birth, neonatal intensive care unit admission, need for respiratory support, hyperbilirubinemia, 5-minute Apgar <7, shoulder dystocia, and perinatal mortality. We calculated pooled odds ratios (OR) with 95% confidence intervals (CI) using random-effects models. RESULTS: Among 39 eligible studies, 39% of the 5518 pregnancies included were exposed to CSII. Odds of cesarean delivery were higher with CSII (20 studies: 63% vs 56%, odds ratio [OR] 1.3 [95% confidence interval (CI) 1.2-1.5]), but we did not identify a difference in the odds of neonatal hypoglycemia (23 studies: 31% vs 34%, OR 1.1 [95% CI 0.9-1.5]). Among secondary outcomes, only the odds of LGA (20 studies: 47% vs 38%, OR 1.4 [95% CI 1.2-1.6]) were higher in individuals using CSII versus MDI. CONCLUSIONS: Use of CSII (vs MDI) for pregestational DM in pregnancy is associated with higher odds of cesarean delivery and delivery of an LGA neonate. Further evaluation of how CSII use may influence neonatal size and delivery route is warranted.

Pregnancy After Bariatric Surgery.

This JAMA Insights Clinical Update discusses general adaptations for pregnancy after bariatric surgery, including recommendations regarding nutrition, maternal health, and fetal and neonatal risks.

Universal first-trimester cytomegalovirus screening and valaciclovir prophylaxis in pregnant persons: a cost-effectiveness analysis.

BACKGROUND: Recent studies have suggested a possible benefit of valaciclovir prophylaxis to prevent vertical transmission after a positive serologic screen for primary maternal cytomegalovirus infection during pregnancy, although its cost-effectiveness remains uncertain. OBJECTIVE: This study aimed to determine the circumstances under which universal first-trimester maternal serologic screening for maternal cytomegalovirus infection, with valaciclovir prophylaxis to prevent congenital cytomegalovirus, is cost-effective. STUDY DESIGN: This study was a decision analysis from the perspective of the pregnant person to assess whether universal maternal screening in the first trimester of pregnancy, with subsequent valaciclovir prophylaxis (8 g/day from the time of positive serologic screen for primary maternal cytomegalovirus infection to 21 weeks of gestation) for those who are acutely infected, is cost-effective compared with usual care (ie, no routine serologic screening but with amniocentesis if midtrimester sonographic findings suggest cytomegalovirus). For baseline estimates, this study assumed a 35% risk of congenital cytomegalovirus after primary maternal infection and a 71% risk reduction with valaciclovir. This study varied valaciclovir's efficacy to identify whether and at what threshold universal screening would be estimated to be cost-effective, compared with usual care. Monte Carlo analyses were performed. A willingness-to-pay threshold of $100,000/quality-adjusted life year was used to define cost-effectiveness. RESULTS: Under base case estimates, first-trimester universal screening and valaciclovir prophylaxis for seropositive pregnant persons with acute cytomegalovirus infection were not cost-effective, with a cost of $137,854 per maternal quality-adjusted life year but resulted in 14 fewer children affected with cytomegalovirus per 100,000 pregnancies compared with usual care. In 1-way sensitivity analysis, universal screening and treatment were estimated to be the cost-effective strategy if the incidence of primary maternal cytomegalovirus infection exceeds 2.6%, the baseline risk of vertical transmission of cytomegalovirus without prophylaxis is greater than 36.8%, and the risk reduction of vertical transmission of cytomegalovirus with valaciclovir prophylaxis exceeds 75.9%. In Monte Carlo analyses, first-trimester universal serologic screening with valaciclovir prophylaxis was estimated to be the cost-effective strategy in 46.8% of runs. CONCLUSION: Universal first-trimester serologic screening with valaciclovir prophylaxis is not the cost-effective strategy for antenatal management of cytomegalovirus under the base case estimates. Although universal screening is cost-effective in certain circumstances when the efficacy of valaciclovir exceeds the base case, that result was not robust to variation of estimates across their reasonable ranges. These data can inform future studies to evaluate screening and treatment to prevent congenital cytomegalovirus.

Critical Evaluation of Clinical Research in Obstetrics and Gynecology.

Within the evolving field of obstetrics and gynecology, providers should possess the ability to effectively and critically evaluate medical literature in order to best adapt and incorporate evidence-based practice. For both clinicians and researchers alike, we provide a systematic approach for reviewing a journal article published in the medical literature. We summarize the various types of study designs, with dedicated attention to observational and experimental studies, and examine sources of bias inherent to these study designs. Finally, we review important considerations when interpreting the validity and significance of the results and conclusions of a research study.

Neighborhood deprivation and preterm delivery during the coronavirus 2019 pandemic.

BACKGROUND: Prior studies have reported decreases in the preterm delivery incidence during the COVID-19 pandemic. However, the findings are inconsistent. Given the wide disparities in the pandemic's impact across communities, neighborhood deprivation may explain the observed variation in the relationship between the COVID-19 pandemic and preterm delivery. OBJECTIVE: To characterize the changes in the incidence of preterm delivery during the COVID-19 pandemic with attention to the effect modification introduced by neighborhood hardship. STUDY DESIGN: This retrospective cohort study included all the pregnant patients who delivered at an urban tertiary care hospital during the pandemic (April-November 2020) or before the pandemic (April-November 2019). We compared the incidence of preterm delivery, spontaneous preterm delivery, and medically indicated preterm delivery before 37 weeks' gestation across epochs. Planned analyses stratified the cohorts by neighborhood deprivation metrics defined by the residential zip code; the metrics included the median neighborhood household income and the hardship index (a composite index including dependency, educational attainment, unemployment, poverty, per capita income, and crowded housing). The Breslow-Day test for homogeneity assessed the association of the delivery epoch and neighborhood deprivation with the preterm delivery outcomes. RESULTS: Of 16,544 eligible deliveries, 8.7% occurred preterm. The incidences of preterm delivery (8.4% vs 9.0%; P=.17), spontaneous preterm delivery (5.0 vs 5.4%; P=.27), and medically indicated preterm delivery (3.2% vs 3.5%; P=.47) were similar in the pandemic and prepandemic epochs. However, the preterm delivery (odds ratio, 0.78; 95% confidence interval, 0.64-0.96) and spontaneous preterm delivery (odds ratio, 0.76; 95% confidence interval, 0.59-0.99) decreased from the prepandemic to the pandemic epoch in those living in neighborhoods <50th percentile for median income (Breslow-Day P values.047 and.036, respectively). Similarly, the preterm delivery (odds ratio, 0.78; 95% confidence interval, 0.64-0.97) and spontaneous preterm delivery (odds ratio, 0.74; 95% confidence interval, 0.57-0.98) decreased for those inhabiting the neighborhoods in the highest-hardship quartile (Breslow-Day P values.045 and.029, respectively). CONCLUSION: The populations residing in socioeconomically disadvantaged neighborhoods experienced reductions in preterm delivery during the COVID-19 pandemic. Neighborhood-level social determinants of health offer insight into the complex etiologies that contribute to preterm delivery and provide opportunities for public health and equity-focused prevention strategies.

Laboratory analysis of symptomatic and asymptomatic pregnant patients with SARS-CoV-2 infection.

BACKGROUND: Inflammatory biomarkers have been used to portend disease severity in nonpregnant individuals with SARS-CoV-2 infection. However, currently, limited data are available, and with mixed results, to elucidate which inflammatory biomarkers may be most associated with clinical phenotype in pregnant patients. OBJECTIVE: We aimed to compare laboratory findings among pregnant patients with SARS-CoV-2 infection by symptom status and disease severity. STUDY DESIGN: We retrospectively evaluated pregnant patients with positive SARS-CoV-2 infection, confirmed through polymerase chain reaction testing, at an urban academic US hospital between March 2020 and October 2020, performed for reported symptoms or universal screening on admission. In our hospital, all patients with SARS-CoV-2 infection were recommended to have baseline laboratory testing, including leukocyte, neutrophil, and lymphocyte counts; aspartate aminotransferase and alanine aminotransferase; high-sensitivity C-reactive protein; procalcitonin; lactate dehydrogenase; D-dimer; and ferritin. We performed multivariable logistic regression to evaluate peak laboratory abnormalities significantly associated with symptomatic SARS-CoV-2 infection and disease severity with gestational age at diagnosis, maternal age, and obesity as covariates. The sensitivity and specificity of laboratory abnormalities were calculated to identify symptomatic vs asymptomatic infection and severe to critical disease vs mild to moderate disease. RESULTS: We identified 175 pregnant patients with SARS-CoV-2 infection, of whom 100 (57%) were symptomatic; 17 (17%) of those who were symptomatic had a severe to critical disease. Laboratory data were available for 128 patients, of whom 67 (52%) were symptomatic. Compared with asymptomatic individuals, symptomatic individuals were more likely to exhibit elevated high-sensitivity C-reactive protein levels after adjusting for gestational age (adjusted odds ratio, 5.67; 95% confidence interval, 1.42-22.52; sensitivity, 81%; specificity, 43%). In symptomatic individuals, transaminitis (adjusted odds ratio, 5.67; 95% confidence interval, 1.27-25.43), elevated procalcitonin levels (adjusted odds ratio, 16.60; 95% confidence interval, 2.61-105.46), and elevated lactate dehydrogenase levels (adjusted odds ratio, 17.55; 95% confidence interval, 2.51-122.78) were independently associated with severe to critical disease rather than mild to moderate disease after adjusting for maternal age and obesity. For differentiating disease severity, sensitivity rates for transaminitis, procalcitonin elevation, and lactate dehydrogenase elevation were 47%, 87%, and 53%, respectively, whereas the specificity rates were 89%, 63%, and 90%, respectively. CONCLUSION: Inflammatory biomarkers in pregnant patients with SARS-CoV-2 infection exhibited vast heterogeneity, poor discriminative ability, and thereby limited clinical utility. Larger registry studies should evaluate which inflammatory biomarkers may be most useful for risk stratification and prognostication of pregnant patients with SARS-CoV-2 infection, taking into account the physiology of pregnancy.

Electrically elicited quadriceps muscle torque: Comparison at three knee angles.

Background and Purpose: The effect of knee angle on electrically elicited quadriceps muscle torque has not been established. The goal of this study was to determine which knee angle allowed for the production of the greatest knee extensor maximal voluntary isometric torque (KEMVIT), the greatest electrically elicited torque, and the highest percent of KEMVIT from the knee extensor muscles. Case Description: Eighteen participants were secured in a force dynamometer with the knee positioned at 30°, 60°, and 90° flexion. Participants performed KEMVITs followed by electrically elicited contractions to their maximum tolerance. Outcomes: The mean ± SD of the peak KEMVITs was 123.7 ± 35.7 Nm, 222.6 ± 67.1 Nm, and 248.2 ± 81.1 Nm at 30°, 60°, and 90°, respectively. Significantly greater KEMVITs were produced at 60° and 90° than at 30° (p < 0.001). The mean ± SD of the maximally tolerated electrically elicited torques was 71.8 ± 18.8 Nm, 170.9 ± 70.4 Nm, and 134.6 ± 72.6 Nm at 30°, 60°, and 90°, respectively. Significantly higher torques were tolerated at 60° than at 30° (p < 0.001) and 90° (p = 0.018). The mean ± SD of the percent KEMVITs was 59.7 ± 11.7%, 78.2 ± 23.8%, and 52.6 ± 18.7% at 30°, 60°, and 90°, respectively. Significantly greater percent KEMVITs were produced at 60° than at 30° (p = 0.001) and 90° (p < 0.001). Discussion: Electrically elicited quadriceps torque production is greater at 60° as compared to 30° and 90° knee flexion.

Comparative Effectiveness of 2 Diabetes Prevention Lifestyle Programs in the Workplace: The City and County of San Francisco Diabetes Prevention Trial.

INTRODUCTION: Data on the comparative effectiveness of Diabetes Prevention Programs (DPPs) in the workplace are limited. METHODS: Between September 2015 and July 2016, employees of the City and County of San Francisco who were at risk for type 2 diabetes (N = 158) were randomly assigned to one of 2 DPP-derived programs recognized by the Centers for Disease Control and Prevention: an in-person YMCA-DPP (n = 78) or an online virtual lifestyle management DPP (VLM-DPP) offered through Canary Health (n = 80). The primary outcome was change in body weight assessed at 6 and 12 months. Follow-up ended in August 2017. RESULTS: Both the YMCA-DPP and VLM-DPP yielded a significant reduction in percentage body weight at 6 months. For the YMCA-DPP, mean percentage change at 6 months was -2.70% (95% confidence interval [CI], -3.91% to -1.48%) and at 12 months was -2.46% (95% CI, -4.24% to -0.68%). For the VLM-DPP, mean percentage change at 6 months was -2.41% (95% CI, -4.07% to -0.77%) and at 12 months was -1.59% (95% CI, -3.51% to 0.33%). The mean between-condition difference at 6 months was -0.25% (95% CI, -2.04% to 1.55%) and at 12 months was -0.84% (95% CI, -3.03% to 1.34%). No significant differences were observed between conditions. The YMCA-DPP had a slightly higher reduction in waist circumference than VLM-DDP at 6 months (mean between-condition difference -2.00 cm [95% CI, -4.24 to 0.25 cm]). Participant engagement, expressed as mean number of completed core program sessions, was significantly higher for the YMCA-DPP than the VLM-DPP. Participants of the YMCA-DPP completed an average of 10.2 sessions (95% CI, 9.0 to 11.4), and participants of the VLM-DPP completed an average of 5.9 sessions (95% CI, 4.7 to 7.1). The adjusted mean between-condition difference was 4.2 sessions (95% CI, 2.54 to 5.99). CONCLUSION: Both the YMCA-DPP and VLM-DPP yielded weight loss at 6 months, which was maintained at 12 months in the YMCA-DPP. The workplace may be an effective setting to offer DPPs.

Molecular Epidemiology of Ceftriaxone Non-Susceptible Enterobacterales Isolates in an Academic Medical Center in the United States.

BACKGROUND: Knowledge of whether Enterobacterales are not susceptible to ceftriaxone without understanding the underlying resistance mechanisms may not be sufficient to direct appropriate treatment decisions. As an example, extended-spectrum ß-lactamase (ESBL)-producing organisms almost uniformly display non-susceptibility to ceftriaxone. Regardless of susceptibility to piperacillin-tazobactam or cefepime, carbapenem antibiotics are the treatment of choice for invasive infections. No such guidance exists for ceftriaxone non-susceptible organisms with mechanisms other than ESBL production. We sought to investigate the molecular epidemiology of ceftriaxone non-susceptible Enterobacterales. METHODS: All consecutive Escherichia coli, Klebsiellapneumoniae, Klebsiella oxytoca, or Proteus mirabilis clinical isolates with ceftriaxone MICs of ≥2 mcg/mL from unique patients at a United States hospital over an 8-month period were evaluated for ß-lactamase genes using a DNA microarray-based assay. RESULTS: Of 1929 isolates, 482 (25%) had ceftriaxone MICs of ≥2 mcg/mL and were not resistant to any carbapenem antibiotics. Of the 482 isolates, ESBL (blaCTX-M, blaSHV, blaTEM) and/or plasmid-mediated ampC (p-ampC) genes were identified in 376 (78%). ESBL genes were identified in 310 (82.4%), p-ampC genes in 2 (0.5%), and both ESBL and p-ampC genes in 64 (17.0%) of the 376 organisms. There were 211 (56%), 120 (32%), 41 (11%), and 4 (1%) isolates with 1, 2, 3, or 4 or more ESBL or p-ampC genes. The most common ESBL genes were of the blaCTX-M-1 group (includes blaCTX-M-15) and the most common p-ampC gene was the blaCMY-2. CONCLUSIONS: There is considerable diversity in the molecular epidemiology of ceftriaxone non-susceptible Enterobacterales. An understanding of this diversity can improve antibiotic decision-making.

A System-Wide Approach to Prevention of In-Hospital Newborn Falls.

BACKGROUND: The Centers for Disease Control and Prevention lists accidents (unintentional injuries) as the fifth leading cause of infant mortality. Data analysis from a multihospital system of inpatient family birth centers revealed fluctuations in newborn birth admission falls rates at times above the benchmark reported in the literature. PURPOSE: We describe a multipronged approach to address an identified safety concern. The aim of the project was to decrease the rate of newborn falls during birth hospitalization. Despite applying multiple interventions described in the literature, newborn falls were not eliminated. STUDY DESIGN AND METHODS: In this quality improvement project, a nursing leadership team was convened to review the literature, identify current and ideal states, obtain stakeholder input, identify contributing factors, and agree on standardized interventions to prevent newborn falls. The project received exempt status from the institutional review board. RESULTS: Since we started the project in 2016, there was a downward trend in newborn birth admission falls in 2017; however, based on our variable data over the last 5 years and small numbers of falls, it is difficult to conclude that any one strategy or combination of strategies has been successful. Because falls from bed with the new mother were the most common types of newborn falls, interventions were focused; however, our falls rate for newborns never fell below comparable rates in the literature. CLINICAL IMPLICATIONS: More data are needed on effective interventions that can reduce the rate of newborn falls, especially those from bed while with the new mother. A comprehensive approach based on analysis of events and review of existing evidence are necessary first steps.

Photo-immobilized EGF chemical gradients differentially impact breast cancer cell invasion and drug response in defined 3D hydrogels.

Breast cancer cell invasion is influenced by growth factor concentration gradients in the tumor microenvironment. However, studying the influence of growth factor gradients on breast cancer cell invasion is challenging due to both the complexities of in vivo models and the difficulties in recapitulating the tumor microenvironment with defined gradients using in vitro models. A defined hyaluronic acid (HA)-based hydrogel crosslinked with matrix metalloproteinase (MMP) cleavable peptides and modified with multiphoton labile nitrodibenzofuran (NDBF) was synthesized to photochemically immobilize epidermal growth factor (EGF) gradients. We demonstrate that EGF gradients can differentially influence breast cancer cell invasion and drug response in cell lines with different EGF receptor (EGFR) expression levels. Photopatterned EGF gradients increase the invasion of moderate EGFR expressing MDA-MB-231 cells, reduce invasion of high EGFR expressing MDA-MB-468 cells, and have no effect on invasion of low EGFR-expressing MCF-7 cells. We evaluate MDA-MB-231 and MDA-MB-468 cell response to the clinically tested EGFR inhibitor, cetuximab. Interestingly, the cellular response to cetuximab is completely different on the EGF gradient hydrogels: cetuximab decreases MDA-MB-231 cell invasion but increases MDA-MB-468 cell invasion and cell number, thus demonstrating the importance of including cell-microenvironment interactions when evaluating drug targets.

Designing Peptide and Protein Modified Hydrogels: Selecting the Optimal Conjugation Strategy.

Hydrogels are used in a wide variety of biomedical applications including tissue engineering, biomolecule delivery, cell delivery, and cell culture. These hydrogels are often designed with a specific biological function in mind, requiring the chemical incorporation of bioactive factors to either mimic extracellular matrix or to deliver a payload to diseased tissue. Appropriate synthetic techniques to ligate bioactive factors, such as peptides and proteins, onto hydrogels are critical in designing materials with biological function. Here, we outline strategies for peptide and protein immobilization. We specifically focus on click chemistry, enzymatic ligation, and affinity binding for transient immobilization. Protein modification strategies have shifted toward site-specific modification using unnatural amino acids and engineered site-selective amino acid sequences to preserve both activity and structure. The selection of appropriate protein immobilization strategies is vital to engineering functional hydrogels. We provide insight into chemistry that balances the need for facile reactions while maintaining protein bioactivity or desired release.

6-Bromo-7-hydroxy-3-methylcoumarin (mBhc) is an efficient multi-photon labile protecting group for thiol caging and three-dimensional chemical patterning.

The photochemical release of chemical reagents and bioactive molecules provides a useful tool for spatio-temporal control of biological processes. However, achieving this goal requires the development of highly efficient one- and two-photon sensitive photo-cleavable protecting groups. Thiol-containing compounds play critical roles in biological systems and bioengineering applications. While potentially useful for sulfhydryl protection, the 6-bromo-7-hydroxy coumarin-4-ylmethyl (Bhc) group can undergo an undesired photoisomerization reaction upon irradiation that limits its uncaging efficiency. To address this issue, here we describe the development of 6-bromo-7-hydroxy-3-methylcoumarin-4-ylmethyl (mBhc) as an improved group for thiol-protection. One- and two-photon photolysis reactions demonstrate that a peptide containing a mBhc-caged thiol undergoes clean and efficient photo-cleavage upon irradiation without detectable photoisomer production. To test its utility for biological studies, a K-Ras-derived peptide containing an mBhc-protected thiol was prepared by solid phase peptide synthesis using Fmoc-Cys(mBhc)-OH for the introduction of the caged thiol. Irradiation of that peptide using either UV or near IR light in presence of protein farnesyltransferase (PFTase), resulted in generation of the free peptide which was then recognized by the enzyme and became farnesylated. To show the utility of this caging group in biomaterial applications, we covalently modified hydrogels with mBhc-protected cysteamine. Using multi-photon confocal microscopy, highly defined volumes of free thiols were generated inside the hydrogels and visualized via reaction with a sulfhydryl-reactive fluorophore. The simple synthesis of mBhc and its efficient removal by one- and two-photon processes make it an attractive protecting group for thiol caging in a variety of applications.