Ultrasound Imaging of Various Ingested Foreign Bodies in an Ex Vivo Intestinal Model.

OBJECTIVE: Foreign body ingestion is an increasingly prevalent issue for children who are in the preverbal to early verbal stages of life. Foreign bodies lodged in the gastrointestinal tract can cause issues such as obstruction, perforation, and fistulae. Radiographic imaging can often locate most foreign bodies; however, radiolucent objects may be missed. Ultrasound is an alternative imaging modality that can be used to locate and track foreign objects as they pass through the bowel. The objective of this study was to characterize the sonographic appearance of various ingested foreign bodies of varying characteristics in an ex vivo gastrointestinal tract segment. METHODS: A GE Logiq 9 ultrasound machine with a linear transducer at a frequency of 15 MHz was used to examine various ingested foreign bodies placed in a segment of pig intestinal tract. RESULTS: Imaged objects varied in visual appearance from echogenicity, texture, size, and shape; acoustic shadows and reverberation artifacts cast were particularly distinguishing characteristics. CONCLUSIONS: Ultrasound evaluation to assess foreign body ingestion in the pediatric population may provide a useful alternative or supportive imaging modality in confirming the location and real-time tracking of the ingested item. This may be especially useful for objects of varying radiodensities that cannot always be reliably seen in traditional radiographs.

Convection and extracellular matrix binding control interstitial transport of extracellular vesicles.

Extracellular vesicles (EVs) influence a host of normal and pathophysiological processes in vivo. Compared to soluble mediators, EVs can traffic a wide range of proteins on their surface including extracellular matrix (ECM) binding proteins, and their large size (∼30-150 nm) limits diffusion. We isolated EVs from the MCF10 series-a model human cell line of breast cancer progression-and demonstrated increasing presence of laminin-binding integrins α3ß1 and α6ß1 on the EVs as the malignant potential of the MCF10 cells increased. Transport of the EVs within a microfluidic device under controlled physiological interstitial flow (0.15-0.75 µm/s) demonstrated that convection was the dominant mechanism of transport. Binding of the EVs to the ECM enhanced the spatial concentration and gradient, which was mitigated by blocking integrins α3ß1 and α6ß1. Our studies demonstrate that convection and ECM binding are the dominant mechanisms controlling EV interstitial transport and should be leveraged in nanotherapeutic design.