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Spleen Microcirculation
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
Alan C. Groom, Eric E. Schmidt, Ian C. MacDonald
Microvascular corrosion casting may be applied to spleens of humans as well as laboratory animals. Normal human spleens are available from transplant donors, but a large portion of the organ is used for tissue typing; with surgically removed spleens from various disease states, samples are first taken by the pathologist. In either case, it is possible to obtain a cast from a portion of the organ. In brief, the procedure is as follows. A major arterial branch, distant from any incision, is cannulated and the spleen is perfused with ~1 liter of heparinized Ringer solution at 100 cm H2O pressure, resulting in washout of most of the RBCs from the perfused segment. A low-viscosity methacrylate resin, e.g., modified Batson’s compound35 or Mercox (Dainippon Ink and Chemicals, Tokyo), is then injected at a rate of 2 to 4 ml/min. The volume of compound used varies according to the amount of tissue perfused, but is generally 1 to 5 ml for a “minimal-injection” cast. The organ is then left undisturbed for several hours for polymerization of the resin to occur. Pieces of tissue ~1 cm2 are cut from the filled segment and the tissue is corroded away from these samples with 40% KOH at 60°C for 5 to 6 days. The vascular casts are then carefully rinsed in distilled water, air-dried, mounted on SEM stubs, and sputter-coated with gold for examination by SEM. (For full details, see Reference 4.)
Deficiency of the Wnt receptor Ryk causes multiple cardiac and outflow tract defects
Published in Growth Factors, 2018
Kumudhini Kugathasan, Michael M. Halford, Peter G. Farlie, Damien Bates, Darrin P. Smith, You Fang Zhang, James P. Roy, Maria L. Macheda, Dong Zhang, James L. Wilkinson, Margaret L. Kirby, Donald F. Newgreen, Steven A. Stacker
Vascular corrosion casting of E18.5 embryos revealed the morphology of the great arteries and heart. Over 90% of Ryk−/− mice had defects in the aortic arch (Figure 2 and Table 1). Aortic arch stenosis (AAS; Figure 2(D,E,I–L)) or interruption of the aortic arch (IAA type-B, between the left common carotid (LCC) artery and the left subclavian artery (LSA); Figure 2(M–P)), were the most serious aortic arch defects observed. AAS and IAA were present in 53% and 13% of Ryk−/− mice, respectively (Table 1). Right-sided aortic arch (RSAA) occurred in 5% of Ryk−/− mice (Table 1; Figure 2(F–H)).
Transarterial drug delivery for liver cancer: numerical simulations and experimental validation of particle distribution in patient-specific livers
Published in Expert Opinion on Drug Delivery, 2021
Tim Bomberna, Ghazal Adeli Koudehi, Charlotte Claerebout, Chris Verslype, Geert Maleux, Charlotte Debbaut
There are several limitations to the research, which – at the same time – inspire future work. First, two types of outlet BCs were used: (i) Murray’s law, and (i) the perfusion methodology [20], while neither has been validated in vivo yet. Note that in Table 2 two sets of outlet BCs were reported for a cancer-free scenario in the CL (according to the 2 types of BCs). This discrepancy stresses that, moving forward, more appropriate BCs should ideally be used, preferably validated by or based on patient-specific in vivo measurements. Second, from a modeling perspective, the effect of transient cardiac pulses should ideally be included to more accurately describe the PD in physiological conditions (i.e. for particle release during a specified, clinically achievable time window) [15,16]. Importantly, more attention should be paid to the clinical interpretation of the non-exit particles in these transient conditions. Third, it should be noted that geometries generated from vascular corrosion casting can be slightly expanded compared to in vivo conditions, but that shrinkage of the resin can also occur [39,40,41]. In the future, the use of patient-specific anatomical imaging resulting from CT or MRI scans should be prioritized. Fourth, the scope of this study was limited to studying uncontrolled particle injection in the PHA in two patient-specific geometries. In addition to the parameters studied in this work, other clinically relevant parameters (such as injection velocity, catheter type, catheter tip orientation, etc.) should also be studied to fully estimate the possibilities offered by parameter optimization [16–19,21]. Future work also should focus on modeling axial injection locations beyond the first bifurcation, up to the point where the vasculature becomes inaccessible for catheters. As such, the workflow proposed in this study can be repeated for this larger range of axial locations to investigate the impact of parameter optimization for injection further downstream. Similarly, injections with more precise control of in-plane catheter tip location should be studied. Overall, more patient-specific liver geometries should be studied to verify the observations made. Last but not least, the scope of the experimental study was currently limited to a proof-of-concept, but should be expanded to investigate the sensitivity of the experimental PDs toward varying injection conditions and particle parameters.