A novel needle-free WaterJet technique for injecting porcine muscle-derived cells into the urethra

Stress urinary incontinence is the most common type of urinary incontinence. It reduces the quality of life of patients. Actual standard surgical therapeutic modalities are offering a symptomatic relief without treating the underlying disorder. Therefore, we developed a novel cell injection technology to deliver viable cells for recovery of the function of the urethral sphincter by WaterJet (WJ, ERBE). Here we investigated if a) porcine muscle−derived cells (pMDC) could be injected by WJ in both, cadaveric samples and living porcine urethra with high viability, b) the WJ inherits the risk of full tissue penetration of the porcine urethra and thus loss of cells, and c) WJ grants improved precision of cell injection and distribution in tissues targeted. The pMDC were produced from male boars and characterized by qRT−PCR and immunofluorescence. Visualized by Calcein AM vs EthD−1, cells were injected into cadaveric porcine urethral by WaterJet vs William’s Needle. In another in vivo study, cells labelled with PKH 26 or/and BacMam, were injected in living female pigs by WaterJet using either a moderate (E60−10; n = 18) or elevated pressure (E80−10; n = 6) protocol, and follow-up (f/u) of up to 7 days. Cell injections targeted the site of the maximum urethral closure pressure (Aquarius TT, Laborie Medical). After harvesting the whole bladder and urethra, cells were traced by an In Vivo Imaging System (IVIS, PerkinElmer) and visualized by fluorescence microscopy of cryosections. Nuclei were stained by DAPI, muscular tissue by phalloidin-iFluor 488. The pSRY gene was detected by PCR. The distribution of injected pMDC was measured as X−depth, Y−width, Z−height and calculated areas in the XY-, YZ-, XZ- planes were analysed. The distance between sphincter muscle and injected cells (DISIC) was measured simultaneously. The analyses provided experimental evidence that pMDCs injected by WaterJet in vitro were viable. Our in vivo study supported that cells appeared defined cellular somata with distinct nuclei and contained intact chromosomal DNA. The success rates of WJ cell application in living animals were significantly higher (≥ 95%, n = 24) when compared to needle injections. Only one out of six samples with full penetration was observed in the WJ E80−10 group. The analyses of the 3D distribution of cells after WJ injection documented that the Y−width of the WJ E80-10 group was statistically significant wider (P = 0.0479) than that of WJ E60-10 group. The same was recorded for the cell distribution in Z-height (P < 0.0001). The YZ-plane of the WJ E80−10 group was statistically significant larger (P = 0.0005) than that of WJ E60-10 group, as well as XZ-plane (P = 0.0204). The injection depth of WJ E80-10 compared to WJ E60-10 showed a statistically significant decrease in length (P < 0.0001). This indicated that WJ E80-10 injections transported cells closer to the targeted rhabdosphincter, but at a higher risk for full penetration. We conclude that the novel WJ is a fast, precise, and easy-to-use innovative method to inject living cells in tissues with a significantly wider and diffuse distribution, with less disintegration of the tissue targeted, and at higher success rates

The effect of swing leg retraction on biped walking stability is influenced by the walking speed and step-length

Swing Leg Retraction (SLR) is observed in human walking and running. Previous studies have concluded that SLR improves the stability and robustness of biped walking. But this conclusion was based on analysis of robot models that can only walk at a very small range of step-lengths and slow or fixed speeds. By contrast, humans can walk with a large range of speeds and step-lengths. Moreover, human walking patterns have a special feature that has not been considered in the previous studies on SLR effects: At a given walking speed, v, humans prefer a step-length, s, which satisfies the power law, s-v β . Therefore, previous studies on SLR can't tell us whether their conclusion will still hold in the full range of human walking patterns (i.e., various walking speeds and step-lengths). This is the question we want to answer in this paper. In this study, using a simple biped model, we studied how the SLR affects the walking stability in the full range of human walking speeds/step-lengths. Preliminary analysis of both models suggests the same conclusion: (1) SLR improves the stability more evidently in human-preferred walking patterns than in other walking patterns. (2) In walking patterns that are very unlike human-preferred ones, the SLR improves the stability very little, or even deteriorates it drastically. Therefore, the new finding of our study is that how the SLR affects the biped walking stability depends on the walking speed and step-length. SLR does not always improve the stability of biped walking

Fast walking with rhythmic sway of torso in a 2D passive ankle walker

There is a category of biped robots that are equipped with passive or un-actuated ankles, which we call Passive-Ankle Walkers (PAWs). Lack of actuation at ankles is a disadvantage in the fast walking of PAWs. We started this study with an intuitive hypothesis that rhythmic sway of torso may enable faster walking in PAWs. To test this hypothesis, firstly, we optimized the rhythmic sway of torso of a simulated PAW model for fast walking speed, and analyzed the robustness of the optimal trajectories. Then we implemented the optimal trajectories on a real robot. Both the simulation analysis and the experimental results indicated that optimized torso-swaying can greatly increase the walking speed by 40%. By analyzing the walking patterns of the simulated model and the real robot, we identified the reason for the faster walking with swaying-torso: The rhythmic sway of torso enables the robot to walk with a relatively large step-length while still keeninu a hizh sten-frenuencv

Influence on Elastic Wave Propagation Behavior in Polymers Composites: An Analysis of Inflection Phenomena

Particulate polymer composites (PPCs) are widely applied under different elastic wave loading conditions in the automobile, aviation, and armor protection industries. This study investigates the elastic wave propagation behavior of a typical PPC, specifically a Cu/poly (methyl methacrylate) (PMMA) composite, with a wide range of particle contents (30–65 vol. %) and particle sizes (1–100 μm). The results demonstrate an inflection phenomenon in both the elastic wave velocity and attenuation coefficient with increasing volume content. In addition, the inflection point moves to the direction of low content with the increase in particle size. Notably, the elastic wave velocity, attenuation, and wavefront width significantly increased with the particle size. The inflection phenomenon of elastic wave propagation behavior in PPCs is demonstrated to have resulted from particle interaction using the classical scattering theory and finite element analysis. The particle interaction initially intensified and then reduced with increasing particle content. This study elucidates the underlying mechanism governing the elastic wave propagation behavior of high particle content PPCs and provides guidelines for the design and application of wave-absorbing composites

CD24: A Marker for an Extended Expansion Potential of Urothelial Cancer Cell Organoids In Vitro?

Background: Bladder cancer is the most cost-intensive cancer due to high recurrence rates and long follow-up times. Bladder cancer organoids were considered interesting tools for investigating better methods for the detection and treatment of this cancer. Methods: Organoids were generated from urothelial carcinoma tissue samples, then expanded and characterized; the expression of immune modulatory antigens and tumor stem cells markers CD24 and CD44 was explored in early (P ≤ 3) and later (P ≥ 5) passages (P) by immunofluorescence and by quantitative PCR of cDNA. The expression of these factors was investigated in the corresponding cancer tissue samples by immunohistochemistry. Results: The expression of the PD-L1 was detected on some but not all organoids. CD276 and CD47 were observed on organoids in all passages investigated. Organoids growing beyond passage 8 expressed both CD24 and CD44 at elevated levels in early and late cultures. Organoids proliferating to the eighth passage initially expressed both CD24 and CD44, but lost CD24 expression over time, while CD44 remained. Organoids growing only up to the 6th passage failed to express CD24 but expressed CD44. Conclusions: The data indicate that the expression of CD24 in urothelial cancer cell organoids may serve as an indicator for the prolonged proliferation potential of the cells