A portfolio of crosslinked chitosan:collagen blends was prepared, and their microarchitecture and water binding capacity were studied to investigate their application for adipose tissue engineering. Glutaraldehyde (GA) concentration had little effect on scaffold morphology or water binding capacity. However, the processing freezing temperature prior to lyophilization affected both. In vitro cytocompatibility of pre-adipocytes (PAs) was assessed for a candidate collagen:chitosan blend using two assays. Results confirm the viability of PAs on GA-crosslinked collagen:chitosan scaffolds. A rat subcutaneous pocket assay was employed to assess PA-seeded scaffolds in vivo. Animal tests proved that PA-seeded scaffolds were biocompatible, could induce vascularization, and form adipose tissue.

The echinoderm nervous system is one of the least studied among invertebrates, partly because the tools available to study the neurobiology of this phylum are limited. We have now produced a monoclonal antibody (RN1) that labels a nervous system component of the sea cucumber Holothuria glaberrima. Western blots show that our antibody recognizes a major band of 66 kDa and a minor band of 53 kDa. Immunohistological experiments show that, in H. glaberrima, the antibody distinctly labels most of the known nervous system structures and some components that were previously unknown or little studied. A surprising finding was the labeling of nervous plexi within the connective tissue compartments of all organs studied. Double labeling with holothurian neuropeptides and an echinoderm synaptotagmin showed that RN1 labeled most, if not all, of the fibers labeled by these neuronal markers, but also a larger component of cells and fibers. The presence of a distinct connective tissue plexus in holothurians is highly significant since these organisms possess mutable connective tissues that change viscosity under the control of the nervous system. Therefore, the cells and fibers recognized by our monoclonal antibodies may be involved in controlling tensility changes in echinoderm connective tissue.

Cardiac conduction devices (CCDs) depend on correct anatomic positioning to function properly. Chest radiography is the preferred imaging modality to evaluate CCD's anatomic location, lead wire integrity, and help in identifying several complications. In this pictorial review, our goal is to familiarize radiologists with CCD implantation techniques, appropriate positioning of the device, common causes of malfunction, methods to improve report accuracy, and assure maximal therapeutic benefit.

Background Cardiac 3D navigator‐gated late gadolinium enhancement (LGE) imaging is important for assessment of left atrial fibrosis, but the image quality is often degraded due to arrhythmia. Purpose To investigate a novel 3D LGE sequence with improved myocardial nulling and reduced ghosting artifacts during arrhythmia. Study Type Prospective. Population Arrhythmia patients (n = 14). Sequence The proposed technique, REPAIRit (Regrowth Equalization Pulse for Arrhythmias in Inversion Recovery with automatic inversion time calculation), inserts a saturation pulse with a dynamic flip angle into the 3D LGE sequence to minimize arrhythmia‐induced signal fluctuations. Using ShMOLLI (shortened modified Look–Locker imaging) to estimate myocardial T1, REPAIRit automatically calculates the optimal inversion time (TI) based on Bloch equations. Assessment REPAIRit LGE and the standard LGE were compared with simulations, phantom imaging, and patient studies. Patient images were assessed quantitatively, based on ghost‐to‐noise ratio (GNR), blood signal‐to‐noise ratio (SNRb), myocardial signal‐to‐noise ratio (SNRm), and blood‐to‐myocardium contrast‐to‐noise ratio (CNR), and qualitatively on a 4‐point scale. Patients were subgrouped based on the presence of arrhythmia to assess the image quality difference. Statistical Tests The two LGE sequences were compared by Student's t‐test and Wilcoxon signed‐rank test. The two patient‐subgroups were compared using Welch's t‐test and Wilcoxon rank‐sum test. Results In 14 analyzed patients, REPAIRit LGE significantly lowered GNR (1.25 ± 0.41 vs. 1.42 ± 0.42, P = 0.04), reduced SNRm (1.90 ± 0.60 vs. 3.16 ± 1.66, P = 0.01), improved ghosting artifact scores (2.5 ± 0.6 vs. 2.2 ± 0.9, P = 0.03), myocardial nulling scores (2.7 ± 0.5 vs. 2.3 ± 0.7, P = 0.02), and atrial quality scores (2.8 ± 0.3 vs. 2.4 ± 0.8, P = 0.03) compared with the standard LGE. Comparing patients with arrhythmia (n = 6) to those without (n = 8) during the scan, the former had lower left ventricular (LV) myocardial T1s (430 ± 26 msec vs. 469 ± 39 msec, P = 0.06) but similar blood T1s (318 ± 55 msec vs. 316 ± 27 msec, P = 0.96), and significantly lower blood SNR (5.2 ± 1.8 vs. 9.2 ± 3.0, P = 0.01) and significantly worse image quality (P = 0.01 for REPAIRit and P = 0.03 for standard). Data Conclusion REPAIRit improves myocardial nulling and reduces ghosting artifacts of 3D LGE under arrhythmia. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:688–699.

Background Cardiac dark-blood turbo spin-echo (TSE) imaging is sensitive to through-plane motion, resulting in myocardial signal reduction. Purpose To propose and validate reverse double inversion-recovery (RDIR)—a dark-blood preparation with improved motion robustness for the cardiac dark-blood TSE sequence. Study Type Prospective. Population Healthy volunteers (n=10) and patients (n=20) Field Strength 1.5T (healthy volunteers) and 3T (patients) Assessment Compared to double inversion recovery (DIR), RDIR swaps the two inversion pulses in time and places the slice-selective 180° in late-diastole of the previous cardiac cycle to minimize slice mis-registration. RDIR and DIR were performed in the same left-ventricular basal short-axis slice. Healthy subjects were imaged with two preparation slice-thicknesses, 110% and 200%, while patients were imaged using a 200% slice-thickness only. Images were assessed quantitatively, by measuring the myocardial signal heterogeneity and the extent of dropout, and also qualitatively on a 5-point scale. Statistical Tests Quantitative and qualitative data were assessed with Student’s t-test and Wilcoxon signed-rank test, respectively. Results In healthy subjects, RDIR with 110% slice-thickness significantly reduced signal heterogeneity in both the left ventricle (LV) and right ventricle (RV) (LV: p=0.006, RV: p<0.0001) and the extent of RV dropout (p<0.0001), while RDIR with 200% slice-thickness significantly reduced RV signal heterogeneity (p=0.001) and the extent of RV dropout (p=0.0002). In patients, RDIR significantly reduced RV myocardial signal heterogeneity (0.31 vs. 0.43; p=0.003) and the extent of RV dropout (24% vs. 46%; p=0.0005). LV signal heterogeneity exhibited a trend towards improvement with RDIR (0.12 vs. 0.16; p=0.06). Qualitative evaluation showed a significant improvement of LV and RV visualization in RDIR compared to DIR (LV: p= 0.04, RV: p=0.0007) and a significantly improved overall image quality (p=0.03). Data Conclusion RDIR TSE is less sensitive to through-plane motion, potentiating increased clinical utility for black-blood TSE.