Browsing by Subject "viability"

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    Improved autologous cortical bone harvest and viability with 2Flute otologic burs
    (Wiley, 2018-01) Roth, Adam A.; Tang, Pei-Ciao; Ye, Michael J.; Mohammad, Khalid S.; Nelson, Rick F.; Otolaryngology -- Head and Neck Surgery, School of Medicine
    Objectives To determine if 2Flute (Stryker Corporation, Kalamazoo, MI) otologic burs improve the size, cellular content, and bone healing of autologous cortical bone grafts harvested during canal wall reconstruction (CWR) tympanomastoidectomy with mastoid obliteration. Study Design Institutional review board-approved prospective cohort study. Methods Human autologous cortical bone chips were harvested using various burs (4 and 6 mm diameter; multiflute, and 2Flute [Stryker Corporation]) from patients undergoing CWR tympanomastoidectomy for the treatment of chronic otitis media with cholesteatoma. Bone chip size, cell counts, cellular gene expression, and new bone formation were quantified. Results Bone chips were significantly larger when harvested with 2Flute (Stryker Corporation) bur compared to multiflute burs at both 6 mm diameter (113 ± 14 μm2 vs. 66 ± 8 μm2; P < 0.05) and 4 mm diameter (70 ± 8 μm2 vs. 50 ± 3 μm2; P < 0.05). After 2 weeks in culture, cell numbers were significantly higher when harvested with 2Flute (Stryker Corporation) bur compared to multiflute burs at both 6 mm diameter (48.7 ± 3 vs. 31.8 ± 3 cells/μg bone; P < 0.05) and 4 mm diameter (27.6 ± 1.2 vs. 8.8 ± 1.2 cells/μg bone; P < 0.05). Bone-derived cells express osteoblast markers (alkaline phosphatase, osteocalcin). Cultured cells are able to form new bone in culture, and bone formation is facilitated by the presence of bone chips. Conclusion Use of 2Flute (Stryker Corporation) otologic burs for human autologous cortical bone harvest results in more viable bone fragments, with larger bone chips and more osteoblasts. Future studies are needed to determine if this leads to improved bone healing.
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    β-aminoisobutyric Acid, L-BAIBA, Is a Muscle-Derived Osteocyte Survival Factor
    (Cell Press, 2018-02-06) Kitase, Yukiko; Vallejo, Julian A.; Gutheil, William; Vemula, Harika; Jähn, Katharina; Yi, Jianxun; Zhou, Jingsong; Brotto, Marco; Bonewald, Lynda F.; Anatomy and Cell Biology, School of Medicine
    Exercise has beneficial effects on metabolism and on tissues. The exercise-induced muscle factor β-aminoisobutyric acid (BAIBA) plays a critical role in the browning of white fat and in insulin resistance. Here we show another function for BAIBA, that of a bone-protective factor that prevents osteocyte cell death induced by reactive oxygen species (ROS). L-BAIBA was as or more protective than estrogen or N-acetyl cysteine, signaling through the Mas-Related G Protein-Coupled Receptor Type D (MRGPRD) to prevent the breakdown of mitochondria due to ROS. BAIBA supplied in drinking water prevented bone loss and loss of muscle function in the murine hindlimb unloading model, a model of osteocyte apoptosis. The protective effect of BAIBA was lost with age, not due to loss of the muscle capacity to produce BAIBA but likely to reduced Mrgprd expression with aging. This has implications for understanding the attenuated effect of exercise on bone with aging.,