Aquasonic 100 ultrasound transmission gel

Prior to performing the warm-up and 1RM back squat protocol, CSA measurements of the participants’ right vastus lateralis (VL) and biceps femoris (BF) muscles were assessed using a linear probe scanning head with a 3.4–10.8 MHz bandwidth range (LOGIQ P6, GE Healthcare, Wauwatosa, WI, USA). The probe was coated with a water soluble transmission gel (Aquasonic 100 ultrasound transmission gel, Parker Laboratories, Inc., Fairfield, NJ, USA) and positioned on the surface of the skin to provide acoustic contact without depressing the dermal layer to collect an image. The CSA images for the VL and BF were obtained using a sweep of the muscle in the extended field of view mode with the gain set to 50 dB and an image depth to 5 cm. For the VL CSA measurements, participants laid on an athletic training table on their left side with their legs together and relaxed with 15° of knee flexion as measured by a manual goniometer [24 (link)]. For the BF CSA measurements, participants laid in a prone position with their feet hanging off the end of the athletic training table. The anatomical location for all CSA measurements was standardized for all participants. VL CSA was measured at 50% of the distance between the greater trochanter and the lateral condyle of the tibia. BF CSA was measured at 50% of the distance between the ischial tuberosity and the posterior aspect of the fibular head.

Short and long term blood perfusion of transplanted spleens was confirmed by high resolution ultrasonography using Vevo 2100 system (FujiFilm VisualSonics, Toronto, ON, Canada).CD45.2⁺ C57BL6/J transplanted recipient mice were anesthetized with isoflurane supplemented with oxygen (2–3 Vol%). Once anesthetized, animals were removed from the induction box and placed in dorsal position on a heated imaging platform and remained anesthetized via a nose cone. Prior to start imaging, the tail vein was catheterized, using a 27-gauge needle connected to a modified P10 tubing catheter, and the anterior abdominal wall was shaved. Aquasonic-100 ultrasound transmission gel (Parker Laboratories, Fairfield, NJ) was applied over the abdominal wall and a 40-MHz imaging transducer was placed longitudinally over the left region of the abdomen. B-mode and color doppler imaging were taken before and after a bolus tail vein injection of 100-μL of microbubbles contrast agent (VEVO non-targeted micromarker microbubbles, FujiFilm VisualSonics) and continue microbubbles injection at a constant rate of 9 μL/min through the duration of spleen imaging.