Comparison of in-person versus virtual ultrasound instruction for pediatric residents.

PURPOSE: Point-of-care ultrasound (POCUS) instruction is prevalent in medical schools but not in pediatric residency programs, even though the majority of pediatric residents desire POCUS instruction. Virtual ultrasound instruction with affordable handheld ultrasound devices may help remedy this deficiency by allowing qualified instructors to circumvent geographic and financial limitations to reach this population. This study sought to determine if virtual ultrasound instruction is an effective alternative to traditional in-person instruction in a cohort of pediatric residents for the extended Focused Assessment with Sonography in Trauma (eFAST) exam. METHODS: Pediatric residents were randomized to receive either in-person or virtual instruction to learn the eFAST exam using a Sonosite Edge (Sonosite, Inc., Bothell, WA) or Butterfly iQ (Butterfly Network, Inc., Guilford, CT), respectively. After the instructional session, the participants completed a timed assessment in which all required images for the eFAST exam were obtained on the same anatomic model. The content and quality of the images were then scored by expert faculty. RESULTS: There were no significant differences in assessment scores (65.8% and 61.8%, p = 0.349) and assessment duration (482.6 s and 432.6 s, p = 0.346) between pediatric residents who received in-person instruction and those who received virtual instruction. CONCLUSION: Virtual ultrasound instruction appears to be an effective alternative to traditional in-person instruction.

Nanocomposite Methacrylated Silk Fibroin-Based Scaffolds for Bone Tissue Engineering.

The treatment of bone defects is a clinical challenge. Bone tissue engineering is gaining interest as an alternative to current treatments, with the development of 3D porous structures (scaffolds) helpful in promoting bone regeneration by ensuring temporary functional support. In this work, methacrylated silk fibroin (SilMA) sponges were investigated as scaffolds for bone tissue engineering by exploiting the combination of physical (induced by NaCl salt during particulate leaching) and chemical crosslinking (induced by UV-light exposure) techniques. A biomimetic approach was adopted to better simulate the extracellular matrix of the bone by introducing either natural (mussel shell-derived) or synthetic-origin hydroxyapatite nanoparticles into the SilMA sponges. The obtained materials were characterized in terms of pore size, water absorption capability and mechanical properties to understand both the effect of the inclusion of the two different types of nanoparticles and the effect of the photocrosslinking. Moreover, the SilMA sponges were tested for their bioactivity and suitability for bone tissue engineering purposes by using osteosarcoma cells, studying their metabolism by an AlamarBlue assay and their morphology by scanning electron microscopy. Results indicate that photocrosslinking helps in obtaining more regular structures with bimodal pore size distributions and in enhancing the stability of the constructs in water. Moreover, the addition of naturally derived hydroxyapatite was observed to be more effective at activating osteosarcoma cell metabolism than synthetic hydroxyapatite, showing a statistically significant difference in the AlamarBlue measurement on day 7 after seeding. The methacrylated silk fibroin/hydroxyapatite nanocomposite sponges developed in this work were found to be promising tools for targeting bone regeneration with a sustainable approach.

Invasion and Secondary Site Colonization as a Function of In Vitro Primary Tumor Matrix Stiffness: Breast to Bone Metastasis.

Increased breast tissue stiffness is correlated with breast cancer risk and invasive cancer progression. However, its role in promoting bone metastasis, a major cause of mortality, is not yet understood. It is previously identified that the composition and stiffness of alginate-based hydrogels mimicking normal (1-2 kPa) and cancerous (6-10 kPa) breast tissue govern phenotype of breast cancer cells (including MDA-MB-231) in vitro. Here, to understand the causal effect of primary tumor stiffness on metastatic potential, a new breast-to-bone in vitro model is described. Together with alginate-gelatin hydrogels to mimic breast tissue, 3D printed biohybrid poly-caprolactone (PCL)-composite scaffolds, decellularized following bone-ECM deposition through Saos-2 engraftment, are used to mimic the bone tissue. It is reported that higher hydrogel stiffness results in the increased migration and invasion capacity of MDA-MB 231 cells. Interestingly, increased expression of osteolytic factors PTHrP and IL-6 is observed when MDA-MB-231 cells pre-conditioned in stiffer hydrogels (10 kPa, 3% w/v gelatin) colonize the bone/PCL scaffolds. The new breast-to-bone in vitro models herein described are designed with relevant tissue microenvironmental factors and could emerge as future non-animal technological platforms for monitoring metastatic processes and therapeutic efficacy.

Role of stiffness and physico-chemical properties of tumour microenvironment on breast cancer cell stemness.

Several physico-chemical properties of the tumour microenvironment (TME) are dysregulated during tumour progression, such as tissue stiffness, extracellular pH and interstitial fluid flow. Traditional preclinical models, although useful to study biological processes, do not provide sufficient control over these physico-chemical properties, hence limiting the understanding of cause-effect relationships between the TME and cancer cells. Breast cancer stem cells (B-CSCs), a dynamic population within the tumour, are known to affect tumour progression, metastasis and therapeutic resistance. With their emerging importance in disease physiology, it is essential to study the interplay between above-mentioned TME physico-chemical variables and B-CSC marker expression. In this work, 3D in vitro models with controlled physico-chemical properties (hydrogel stiffness and composition, perfusion, pH) were used to mimic normal and tumour breast tissue to study changes in proliferation, morphology and B-CSC population in two separate breast cancer cell lines (MCF-7 and MDA-MB 231). Cells encapsulated in alginate-gelatin hydrogels varying in stiffness (2-10 kPa), density and adhesion ligand (gelatin) were perfused (500 µL/min) for up to 14 days. Physiological (pH 7.4) and tumorigenic (pH 6.5) media were used to mimic changes in extracellular pH within the TME. We found that both cell lines have distinct responses to changes in physico-chemical factors in terms of proliferation, cell aggregates size and morphology. Most importantly, stiff and dense hydrogels (10 kPa) and acidic pH (6.5) play a key role in B-CSCs dynamics, increasing both epithelial (E-CSCs) and mesenchymal cancer stem cell (M-CSCs) marker expression, supporting direct impact of the physico-chemical microenvironment on disease onset and progression. STATEMENT OF SIGNIFICANCE: Currently no studies evaluate the impact of physico-chemical properties of the tumour microenvironment on breast cancer stem cell (B-CSC) marker expression in a single in vitro model and at the same time. In this study, 3D in vitro models with varying stiffness, extracellular pH and fluid flow are used to recapitulate the breast tumour microenvironment to evaluate for the first time their direct effect on multiple breast cancer phenotypes: cell proliferation, cell aggregate size and shape, and B-CSC markers. Results suggest these models could open new ways of monitoring disease phenotypes, from the early-onset to progression, as well as being used as testing platforms for effective identification of specific phenotypes in the presence of relevant tumour physico-chemical microenvironment.

Taking the Pulse of POCUS: The State of Point-of-Care Ultrasound at a Pediatric Tertiary Care Hospital.

We aim to quantify and categorize point-of-care ultrasound (POCUS) usage by pediatric practitioners and trainees at our tertiary care center, and assess the degree of interest from pediatric residents, fellows, and program leaders for integrating POCUS into their training. Data was collected via online survey, evaluating the current use of POCUS in clinical decision making, desire for further formal training, and opinions on the importance of POCUS to future clinical practice. In total, 14 program directors/assistant program directors (PD/APDs) representing 10 of 15 training programs, 30 of 95 fellows representing 9 of 15 fellowships, and 32 of 82 residents responded. From PD/APDs, only 2 of the programs reported active use POCUS for clinical decision making, but 13 of the fellows and 9 residents reported doing so. In regard to desire for a formal POCUS program, 30.8% of PD/APDs, 43.8% of fellows without current curricula, and 87.5% of residents were interested in participating in such a program. When considering specialty, some non-acute care-based PD/APDs and fellows at our institution felt that POCUS was important to future practice. Pediatric subspecialty PD/APDs and their fellows had divergent outlooks on the importance of POCUS in future practice. Finally, an overwhelming majority of residents at our institution expressed a desire to learn, and half believing it will be important to future practice. Based on the degree of interest, medicolegal considerations, and trajectory of patient care, pediatric residency and fellowship programs should strongly consider integrating POCUS education into their curricula.

Additively manufactured BaTiO3 composite scaffolds: A novel strategy for load bearing bone tissue engineering applications.

Piezoelectric ceramics, such as BaTiO3, have gained considerable attention in bone tissue engineering applications thanks to their biocompatibility, ability to sustain a charged surface as well as improve bone cells' adhesion and proliferation. However, the poor processability and brittleness of these materials hinder the fabrication of three-dimensional scaffolds for load bearing tissue engineering applications. For the first time, this study focused on the fabrication and characterisation of BaTiO3 composite scaffolds by using a multi-material 3D printing technology. Polycaprolactone (PCL) was selected and used as dispersion phase for its low melting point, easy processability and wide adoption in bone tissue engineering. The proposed single-step extrusion-based strategy enabled a faster and solvent-free process, where raw materials in powder forms were mechanically mixed and subsequently fed into the 3D printing system for further processing. PCL, PCL/hydroxyapatite and PCL/BaTiO3 composite scaffolds were successfully produced with high level of consistency and an inner architecture made of seamlessly integrated layers. The inclusion of BaTiO3 ceramic particles (10% wt.) significantly improved the mechanical performance of the scaffolds (54 ± 0.5 MPa) compared to PCL/hydroxyapatite scaffolds (40.4 ± 0.1 MPa); moreover, the presence of BaTiO3 increased the dielectric permittivity over the entire frequency spectrum and tested temperatures. Human osteoblasts Saos-2 were seeded on scaffolds and cellular adhesion, proliferation, differentiation and deposition of bone-like extracellular matrix were evaluated. All tested scaffolds (PCL, PCL/hydroxyapatite and PCL/BaTiO3) supported cell growth and viability, preserving the characteristic cellular osteoblastic phenotype morphology, with PCL/BaTiO3 composite scaffolds exhibiting higher mineralisation (ALP activity) and deposited bone-like extracellular matrix (osteocalcin and collagen I). The single-step multi-material additive manufacturing technology used for the fabrication of electroactive PCL/BaTiO3 composite scaffolds holds great promise for sustainability (reduced material waste and manufacturing costs) and it importantly suggests PCL/BaTiO3 scaffolds as promising candidates for load bearing bone tissue engineering applications to solve unmet clinical needs.

SNX27-retromer assembly recycles MT1-MMP to invadopodia and promotes breast cancer metastasis.

A variety of metastatic cancer cells use actin-rich membrane protrusions, known as invadopodia, for efficient ECM degradation, which involves trafficking of proteases from intracellular compartments to these structures. Here, we demonstrate that in the metastatic breast cancer cell line MDA-MB-231, retromer regulates the matrix invasion activity by recycling matrix metalloprotease, MT1-MMP. We further found that MT2-MMP, another abundantly expressed metalloprotease, is also invadopodia associated. MT1- and MT2-MMP showed a high degree of colocalization but were located on the distinct endosomal domains. Retromer and its associated sorting nexin, SNX27, phenocopied each other in matrix degradation via selectively recycling MT1-MMP but not MT2-MMP. ITC-based studies revealed that both SNX27 and retromer could directly interact with MT1-MMP. Analysis from a publicly available database showed SNX27 to be overexpressed or frequently altered in the patients having invasive breast cancer. In xenograft-based studies, SNX27-depleted cell lines showed prolonged survival of SCID mice, suggesting a possible implication for overexpression of the sorting nexin in tumor samples.

The association of coagulopathy and traumatic brain injury in patients with isolated head injury.

UNLABELLED: The emergence of prothrombotic agents (e.g. activated factor VII) to treat traumatic brain injury (TBI) requires a better understanding of the association of coagulopathy with isolated head injury (IHI). OBJECTIVE: To investigate the association of IHI and coagulopathy. METHODS: Prospective, observational study in an urban level I trauma center. INCLUSION CRITERIA: Adult (> or = 13 years of age) patients with IHI. EXCLUSION CRITERIA: patients with known coagulopathies or on anticoagulant therapy. PREDICTOR VARIABLES: TBI (head abbreviated injury severity score > 2, or brain hematoma on CT scan), age, gender, mechanism of injury, Glasgow Coma Score (GCS), and loss of consciousness (LOC). OUTCOME VARIABLES: coagulopathy defined as elevated International Normalized Ratio (INR > 1.3) or activated partial thromboplastin time (PTT) greater than 34 s. We divided IHI subjects into two groups of patients with and without TBI. STATISTICAL ANALYSIS: Fisher's exact test and Mann-Whitney U were used to compare data where appropriate (alpha: 0.05, two-tailed). RESULTS: From July 2005 to December 2006, 276 patients with IHI were studied. The median age was 35 years (interquartile range: 25-52) with a 79% male predominance and 88% blunt trauma. Eight percent (95% CI, 5-12%) of patients had coagulopathy. The rate of coagulopathy in TBI patients (17%) was significantly higher than non-TBI patients (6%) (11% difference, 95% CI, 3-20%]. The relative risk of coagulopathy in TBI patients was 2.9 (95% CI, 1.3-6.6). CONCLUSION: Coagulopathy as defined by elevated INR and/or PTT is associated with TBI after isolated head injury.

Identifying traumatic brain injury in patients with isolated head trauma: are arterial lactate and base deficit as helpful as in polytrauma?

BACKGROUND: Increase in lactate (LAC) within the central nervous system after head trauma is an established marker of traumatic brain injury (TBI). OBJECTIVE: To investigate the utility of arterial base deficit (BD) and LAC in identifying TBI in patients with isolated head injury (IHI). MATERIALS AND METHODS: TBI was defined as Glasgow Coma Scale < or =8, head Abbreviated Injury Severity Score >2 or brain haematoma on CT scan. Patients were divided into two groups: IHI with and without TBI. Data were reported as means (SDs). 131 patients with IHI were studied (mean (SD) age 39 (19) years, 78% male). RESULTS: 17% of the patients sustained TBI. The mean differences for arterial BD (0.65 mmol/l, 95% CI -0.8 to 2.1) and LAC (0.34 mmol/l, 95% CI -0.7 to 1.4) in patients with and without TBI were not significant. Analysis of receiver operating characteristic curves confirmed that arterial BD and LAC were unable to detect TBI in patients with IHI. CONCLUSION: Arterial BD and LAC are poor predictors of TBI in isolated head trauma.