This study examined histologically the potential of using allogeneic cultured chondrocyte pellet (CCP) in enhancing bone-tendon junction (BTJ) healing using a rabbit partial patellectomy model. Chondrocytes isolated from the cartilaginous ribs of 6-week-old New Zealand white rabbits were cultured for 14 days to form CCP. Partial patellectomy was performed on 30 18-week-old rabbits. After removal of the distal third patella, the BTJ gap was repaired surgically with or without CCP interposition. Four samples of patella-patellar tendon complexes (PPTC) for each group were harvested each at 8, 12, and 16 weeks; and two additional PPTC for each group were harvested at 2, 4, and 6 weeks for early observation of fibrocartilage zone regeneration, histologically. Results showed that CCP interposition demonstrated earlier structural integration at the BTJ after 8, 12, and 16 weeks of healing, and formation of a fibrocartilage zone like structure, compared with control specimens. In addition, no immune rejection was observed in CCP experimental group. The results suggested that CCP had a stimulatory effect on BTJ healing. This bioengineering approach might have potential clinical application in treatment of difficult BTJ healing. However, systemic histomorphometric, immunological tests, and biomechanical evaluations are needed before any clinical trials.
Background An estimated 10% of male adults have split or dribbled stream leading to poor hygiene, embarrassment, and inconvenience. There is no current metric that measures male stream deviation. Objective To develop a novel method to measure spray in normal and abnormal anatomical conformations. Design, setting, and participants We developed a novel platform to reliably describe spray. We used cadaveric tissues and 3D Printed models to study the impact of meatal shape on the urinary stream. Cadaveric penile tissue and 3D printed models were affixed to a fluid pump and used to simulate micturition. Dye captured on fabric allowed for spray detection. Outcome measurements and statistical analysis Spray pattern area, deviation from normal location, and flowrates were recorded. Computational fluid dynamic models were created to study fluid vorticity. Results and limitations Obstructions at the penile tip worsened spray dynamics and reduced flow. Ventral meatotomy improved flowrate (p<0.05) and reduced spray (p<0.05) compared to tips obstructed ventrally, dorsally or in the fossa navicularis. 3D models do not fully reproduce parameters of their parent cadaver material. The average flowrate from 3D model was 10ml/sec less than that of the penis from which it was derived (p = 0.03). Nonetheless, as in cadavers, increasing obstruction in 3D models leads to the same pattern of reduced flowrate and worse spray. Dynamic modeling revealed increasing distal obstruction was correlated to higher relative vorticity observed at the urethral tip. Conclusions We developed a robust method to measure urine spray in a research setting. Dynamic 3D printed models hold promise as a methodology to study common pathologies in the urethra and corrective surgeries on the urine stream that would not be feasible in patients. These novel methods require further validation, but offer promise as a research and clinical tool.
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