Targeting angiogenesis as a therapeutic means to reinforce osteocyte survival and prevent nonunions in the aftermath of radiotherapy

BackgroundRadiotherapy (XRT) exerts detrimental collateral effects on bone tissue through mechanisms of vascular damage and impediments to osteocytes, ultimately predisposing patients to the debilitating problems of late pathologic fractures and nonunions. We posit that angiogenic therapy will reverse these pathologic effects in a rat model of radiated fracture healing.MethodsThree groups of rats underwent mandibular osteotomy. Radiated groups received a fractionated 35‐Gy dose before surgery. The deferoxamine (DFO) group received local injections postoperatively. A 40‐day healing period was allowed before histology. Analysis of variance (ANOVA; p < .05) was used for group comparisons.ResultsRadiated fractures revealed a significantly decreased osteocyte count and corresponding increase in empty lacunae when compared to nonradiated fractures (p = .001). With the addition of DFO, these differences were not appreciated. Further, a 42% increase in bony unions was observed after DFO therapy.ConclusionTargeting angiogenesis is a useful means for promoting osteocyte survival and preventing bone pathology after XRT. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1261–1267, 2015Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113164/1/hed23744.pd

Role of parathyroid hormone in regeneration of irradiated bone in a murine model of mandibular distraction osteogenesis

BackgroundThe purpose of this study was to measure the histologic and histomorphometric effects of parathyroid hormone (PTH) treatment on irradiated bone undergoing distraction osteogenesis (DO).MethodsThirty‐four rats were divided into 3 groups. The control group underwent DO and the radiation control group underwent radiotherapy (RT) before DO. The PTH group underwent RT and received PTH during DO. Quantitative histology and histomorphometry were performed.ResultsRT resulted in a depletion of osteocytes and increase in empty lacunae. Treatment with PTH resulted in an increase in osteocyte counts and decrease in empty lacunae (p < .05), restoring osteocytes to levels seen in nonradiated bone (p = .121). RT decreased bone volume to tissue volume (BV‐TV) ratio and increased osteoid volume to tissue volume (OV‐TV) ratio, signifying increased immature bone formation. PTH treatment restored OV‐TV ratio to that observed in nonradiated bone.ConclusionPTH treatment of irradiated bone enhanced bone regeneration and restored osteocyte counts and OV‐TV ratio to levels comparable to nonradiated bone. © 2016 Wiley Periodicals, Inc. Head Neck 39: 464–470, 2017Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136287/1/hed24612.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136287/2/hed24612_am.pd

Translational treatment paradigm for managing non‐unions secondary to radiation injury utilizing adipose derived stem cells and angiogenic therapy

BackgroundBony non‐unions arising in the aftermath of collateral radiation injury are commonly managed with vascularized free tissue transfers. Unfortunately, these procedures are invasive and fraught with attendant morbidities. This study investigated a novel, alternative treatment paradigm utilizing adipose‐derived stem cells (ASCs) combined with angiogenic deferoxamine (DFO) in the rat mandible.MethodsRats were exposed to a bioequivalent dose of radiation and mandibular osteotomy. Those exhibiting non‐unions were subsequently treated with surgical debridement alone or debridement plus combination therapy. Radiographic and biomechanical outcomes were assessed after healing.ResultsSignificant increases in biomechanical strength and radiographic metrics were observed in response to combination therapy (p < .05). Importantly, combined therapy enabled a 65% reduction in persisting non‐unions when compared to debridement alone.ConclusionWe support the continued investigation of this promising combination therapy in its potential translation for the management of radiation‐induced bony pathology. © 2015 Wiley Periodicals, Inc. Head Neck 38: E837–E843, 2016Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137613/1/hed24110.pd

Last Generation Solar Cells in Outer Space: A STEM Outreach Project with Middle and High School Students in Colombia

As part of an unprecedented collaborative outreach effort, we implemented an innovative STEM outreach project, where more than 80 middle and high school students from different traditionally underrepresented school districts in Colombia-with no previous knowledge on material science or photovoltaics-created Last Generation Solar Cells (LGSCs) that were part of several suborbital spaceflight missions. As a result, the students were able to contrast visual and instrumental data obtained from the solar cells and modules that were launched to space with similar samples that remained on earth to measure the degradation that occurs during spaceflight conditions. At the same time, the students that participated were able to cultivate their curiosity, strengthen their scientific skills and increase their interest in pursuing careers in STEM fields. These experiences were possible thanks to an extraordinary collaborative network between public and private entities and the use of project-based education as a powerful driver of development, especially for low-to-middle-income countries, such as Colombia. Here, we share our methodology for constructing photovoltaic devices in rural settings, and we show the progression and impact of this novel scientific outreach project

Dose-Response Effect of Human Equivalent Radiation in the Murine Mandible: Part I. A Histomorphometric Assessment

"The palace of the "Gun Gate' was originally double and consisted of summer pavilions at the water's edge--now mainly destroyed by the railway--and the winter palace on the ridge overlooking the city. The courts were arranged in a series: the first contained the armory in the church of Hagia Irene, and various hospitals and barracks; the second was bounded by the reception hall and inner treasury on one side, and the kitchen on the other; the third was used by the palace school; and the fourth consisted of gardens and various pavilions. On the city side, beyond the barracks of the Halberdiers, was the harem. It was divided into distinct sectors: those for eunuchs, laundry and other services, the queen mother's suite, the sultan's rooms and those of his ladies, and the sacred chamber of the Robe of the Prophet and its pavilion."interior, gilded marble tap, Baths of the Sultan and of the Queen Mother, 200

Treatment of landfill leachate by a combined process: Iron electrodissolution, iron oxidation by H2O2 and chemical flocculation

The efficiency of iron electrodissolution and the flocculation processes with Fe2+ and Fe3+ for removing color, turbidity, chloride and chemical oxygen demand (COD) were studied by treating a landfill leachate effluent from âEl Carrascoâ (Bucaramanga, Colombia). The pH and current density for the electrodissolution treatment were determined from potentiodynamic polarization studies. The electrodissolution process was performed under galvanostatic conditions at 24 A mâ2 with changing polarity of the electrodes. Hydrogen peroxide was used for the oxidation of Fe2+ to Fe3+ while Ca(OH)2 was used for the flocculation as the pH modifier and coagulant adjuvant agent along with an anionic polyacrylamide. The results showed that higher removal efficiencies of the COD, color and turbidity were obtained (85, 96 and 76%, respectively) using 0.225 g Lâ1 of hydrogen peroxide at pH about 8.5 after 150 min; requiring 0.6 kWh mâ3 and a total treatment cost of 2.24 USD mâ3. Keywords: Leachate, Iron electrodissolution, Potentiodynamic polarization, Flocculatio