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Winner of the 2013 Young Investigator Award for the Society for Biomaterials annual meeting and exposition, April 10-13, 2013, Boston, Massachusetts. Osteogenic differentiation of mesenchymal stem cells on demineralized and devitalized biodegradable polymer and extracellular matrix hybrid constructs.

ABSTRACT: Devitalization and demineralization processing of biodegradable polymer and extracellular matrix (ECM) hybrid constructs was explored for the effect on the retention of ECM components and construct osteogenicity. Hybrid constructs were generated by seeding osteogenically predifferentiated rat mesenchymal stem cells (MSCs) onto electrospun poly(?-caprolactone) fiber meshes and culturing in osteogenic medium for 12 or 16 days within a flow perfusion bioreactor to create an ECM coating. The resulting constructs were then either devitalized (using a freeze-thaw or a detergent technique), devitalized and demineralized, or left untreated, and subsequently characterized for DNA, glycosaminoglycan, collagen, and calcium content. The osteogenicity of each construct was investigated by culturing MSCs on the hybrid constructs within a flow perfusion bioreactor for 4, 8, and 12 days in osteogenic medium. Histological staining demonstrated that devitalization via the freeze-thaw method retained the thickest coating of ECM components within the constructs. Demineralization and devitalization processing of ECM coated constructs resulted in a decrease in their osteogenicity.

SUBMITTER: Thibault RA

PROVIDER: S-EPMC3677758 | biostudies-other | 2013 May

REPOSITORIES: biostudies-other

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Winner of the 2013 Young Investigator Award for the Society for Biomaterials annual meeting and exposition, April 10-13, 2013, Boston, Massachusetts. Osteogenic differentiation of mesenchymal stem cells on demineralized and devitalized biodegradable polymer and extracellular matrix hybrid constructs.

Thibault Richard A RA Mikos Antonios G AG Kasper F Kurtis FK

Journal of biomedical materials research. Part A 20130316 5

Devitalization and demineralization processing of biodegradable polymer and extracellular matrix (ECM) hybrid constructs was explored for the effect on the retention of ECM components and construct osteogenicity. Hybrid constructs were generated by seeding osteogenically predifferentiated rat mesenchymal stem cells (MSCs) onto electrospun poly(ε-caprolactone) fiber meshes and culturing in osteogenic medium for 12 or 16 days within a flow perfusion bioreactor to create an ECM coating. The resulti ...[more]

PMID: 23505119

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Project description:Study designRetrospective hospital-registry study.ObjectiveTo characterize the microbial epidemiology of surgical site infection (SSI) in spinal fusion surgery and the burden of resistance to standard surgical antibiotic prophylaxis.Summary of background dataSSI persists as a leading complication of spinal fusion surgery despite the growth of enhanced recovery programs and improvements in other measures of surgical quality. Improved understandings of SSI microbiology and common mechanisms of failure for current prevention strategies are required to inform the development of novel approaches to prevention relevant to modern surgical practice.MethodsSpinal fusion cases performed at a single referral center between January 2011 and June 2019 were reviewed and SSI cases meeting National Healthcare Safety Network criteria were identified. Using microbiologic and procedural data from each case, we analyzed the anatomic distribution of pathogens, their differential time to presentation, and correlation with methicillin-resistant Staphylococcus aureus screening results. Susceptibility of isolates cultured from each infection were compared with the spectrum of surgical antibiotic prophylaxis administered during the index procedure on a per-case basis. Susceptibility to alternate prophylactic agents was also modeled.ResultsAmong 6727 cases, 351 infections occurred within 90 days. An anatomic gradient in the microbiology of SSI was observed across the length of the back, transitioning from cutaneous (gram-positive) flora in the cervical spine to enteric (gram-negative/anaerobic) flora in the lumbosacral region (correlation coefficient 0.94, P < 0.001). The majority (57.5%) of infections were resistant to the prophylaxis administered during the procedure. Cephalosporin-resistant gram-negative infection was common at lumbosacral levels and undetected methicillin-resistance was common at cervical levels.ConclusionIndividualized infection prevention strategies tailored to operative level are needed in spine surgery. Endogenous wound contamination with enteric flora may be a common mechanism of infection in lumbosacral fusion. Novel approaches to prophylaxis and prevention should be prioritized in this population.Level of Evidence: 3.

Project description:ImportancePrevious studies have shown high mortality rates among homeless people in general, but little is known about the patterns of mortality among "rough sleepers," the subgroup of unsheltered urban homeless people who avoid emergency shelters and primarily sleep outside.ObjectivesTo assess the mortality rates and causes of death for a cohort of unsheltered homeless adults from Boston, Massachusetts.Design, setting, and participantsA 10-year prospective cohort study (2000-2009) of 445 unsheltered homeless adults in Boston, Massachusetts, who were seen during daytime street and overnight van clinical visits performed by the Boston Health Care for the Homeless Program's Street Team during 2000. Data used to describe the unsheltered homeless cohort and to document causes of death were gathered from clinical encounters, medical records, the National Death Index, and the Massachusetts Department of Public Health death occurrence files. The study data set was linked to the death occurrence files by using a probabilistic record linkage program to confirm the deaths. Data analysis was performed from May 1, 2015, to September 6, 2016.ExposureBeing unsheltered in an urban setting.Main outcomes and measuresAge-standardized all-cause and cause-specific mortality rates and age-stratified incident rate ratios that were calculated for the unsheltered adult cohort using 2 comparison groups: the nonhomeless Massachusetts adult population and an adult homeless cohort from Boston who slept primarily in shelters.ResultsOf 445 unsheltered adults in the study cohort, the mean (SD) age at enrollment was 44 (11.4) years, 299 participants (67.2%) were non-Hispanic white, and 72.4% were men. Among the 134 individuals who died, the mean (SD) age at death was 53 (11.4) years. The all-cause mortality rate for the unsheltered cohort was almost 10 times higher than that of the Massachusetts population (standardized mortality rate, 9.8; 95% CI, 8.2-11.5) and nearly 3 times higher than that of the adult homeless cohort (standardized mortality rate, 2.7; 95% CI, 2.3-3.2). Non-Hispanic black individuals had more than half the rate of death compared with non-Hispanic white individuals, with a rate ratio of 0.4 (95% CI, 0.2-0.7; P < .001). The most common causes of death were noncommunicable diseases (eg, cancer and heart disease), alcohol use disorder, and chronic liver disease.Conclusions and relevanceMortality rates for unsheltered homeless adults in this study were higher than those for the Massachusetts adult population and a sheltered adult homeless cohort with equivalent services. This study suggests that this distinct subpopulation of homeless people merits special attention to meet their unique clinical and psychosocial needs.

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