1,472 research outputs found
Effective Doses of Recombinant Human Bone Morphogenetic Protein-2 in Experimental Spinal Fusion
Study Design Nineteen dogs underwent L4-L5 intertransverse process fusions with either 58 μg, 115 μg, 230 μg, 460 μg, or 920 μg of recombinant human bone morphogenetic protein-2 carried by a polylactic acid polymer. A previous study (12 dogs) compared 2300 μg of recombinant human bone morphogenetic protein-2, autogenous iliac bone, and carrier alone in this model. All fusions subsequently were compared.
Objectives To characterize the dose-response relationship of recombinant human bone morphogenetic protein-2 in a spinal fusion model.
Summary of Background Data Recombinant osteoinductive morphogens, such as recombinant human bone morphogenetic protein-2, are effective in vertebrate diaphyseal defect and spinal fusion models. It is hypothesized that the quality of spinal fusion produced with recombinant human bone morphogenetic protein-2, above a threshold dose, does not change with increasing amounts of inductive protein.
Methods After decortication of the posterior elements, the designated implants were placed along the intertransverse process space bilaterally. The fusion sites were evaluated after 3 months by computed tomography imaging, high-resolution radiography, manual testing, mechanical testing, and histologic analysis.
Results As in the study using 2300 μg of recombinant human bone morphogenetic protein-2, implantation of 58–920 μg of recombinant human bone morphogenetic protein-2 successfully resulted in intertransverse process fusion in the dog by 3 months. This had not occurred in animals containing autograft or carrier alone. The cross-sectional area of the fusion mass and mechanical stiffness of the L4-L5 intersegment were not dose-dependent. Histologic findings varied but were not related to rhBMP-2 dose. Inflammatory reaction to the composite implant was proportional inversely to the volume of the fusion mass.
Conclusions No mechanical, radiographic, or histologic differences in the quality of intertransverse process fusion resulted from a 40-fold variation in dose of recombinant human bone morphogenetic protein-2
Estimated Rates of Retinal Ganglion Cell Loss in Glaucomatous Eyes with and without Optic Disc Hemorrhages
Purpose: To evaluate whether optic disc hemorrhages are associated with faster rates of estimated retinal ganglion cell (RGC) loss in glaucoma.Methods: A longitudinal observational cohort study of 222 eyes of 122 patients with glaucoma recruited from the Diagnostic Innovations Glaucoma Study (DIGS) followed for an average of 3.74 +/- 0.85 years. All subjects had optical coherence tomography and standard automated perimetry during follow up. Optic disc hemorrhages were detected by masked evaluation of stereophotographs. Rates of change in estimated numbers of RGCs were determined using a previously described method. A random coefficients model was used to investigate the relationship between disc hemorrhages and rates of change in estimated RGC counts over time.Results: 19 eyes of 18 subjects had at least one disc hemorrhage during follow up. At baseline, average estimated RGC counts in eyes with and without disc hemorrhages were 677,994 cells and 682,021 cells, respectively (P = 0.929). Eyes with optic disc hemorrhages during follow-up had significantly faster rates of estimated RGC loss than eyes without disc hemorrhages (22,233 cells/year versus 10,704 cells/year, P = 0.020). the effect of disc hemorrhages on the rates of estimated RGC loss remained significant after adjusting for confounding variables.Conclusion: Eyes with disc hemorrhages showed faster rates of RGC loss compared to eyes without disc hemorrhages. These results provide further evidence that disc hemorrhages should be considered as an indicator of increased risk for faster neural loss in glaucoma.National Institutes of Health/National Eye InstituteResearch to Prevent Blindness (New York, N.Y.)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)AlconAllerganPfizerMerckSantenUniv Calif San Diego, Hamilton Glaucoma Ctr, San Diego, CA 92103 USAUniv Calif San Diego, Dept Ophthalmol, San Diego, CA 92103 USAUniversidade Federal de São Paulo, Dept Ophthalmol, São Paulo, BrazilUniv Edinburgh, Princess Alexandra Eye Pavil, Edinburgh, Midlothian, ScotlandUniv Edinburgh, Dept Ophthalmol, Edinburgh, Midlothian, ScotlandUniversidade Federal de São Paulo, Dept Ophthalmol, São Paulo, BrazilNational Institutes of Health/National Eye Institute: EY021818National Institutes of Health/National Eye Institute: EY11008National Institutes of Health/National Eye Institute: EY14267National Institutes of Health/National Eye Institute: EY019869National Institutes of Health/National Eye Institute: P30EY022589CAPES: 12309-13-3Web of Scienc
Mesenchymal stromal cells in bronchoalveolar lavage as predictors of bronchiolitis obliterans syndrome
Rationale: Bronchoalveolar lavage fluid (BAL) from human lung
allografts demonstrates the presence of a multipotentmesenchymal
stromal cell population. However, the clinical relevance of this novel
cellular component of BAL and its association with bronchiolitis
obliterans syndrome (BOS), a disease marked by progressive airflow
limitation secondary to fibrotic obliteration of the small airways,
remains to be determined.
Objectives: In this study we investigate the association of number of
mesenchymal stromal cells in BAL with development of BOS in
human lung transplant recipients.
Methods:Mesenchymal colony-forming units (CFUs)were quantitated
in a cohort of 405 BAL samples obtained from 162 lung transplant
recipients. Poisson generalized estimating equations were used to
determine the predictors of BAL mesenchymal CFU count.
Measurements and Main Results: Higher CFU counts were noted early
post-transplantation; time from transplant to BAL of greater than
3 months predicted 0.4-fold lower CFU counts (P = 0.0001). BOS
diagnosis less than or equal to 365 days before BAL was associated
with a 2.11-fold higher CFU count (P = 0.02). There were 2.62- and
2.70-fold higher CFU counts noted in the presence of histologic
diagnosis of bronchiolitis obliterans (P = 0.05) and organizing
pneumonia (0.0003), respectively. In BAL samples obtained from
BOS-free patients greater than 6 months post-transplantation (n =
173), higher mesenchymal CFU counts (>=10) significantly predicted
BOS onset in both univariate (hazard ratio, 5.61; 95%CI, 3.03–10.38;
P < 0.0001) andmultivariate (hazard ratio, 5.02; 95%CI, 2.40–10.51;
P < 0.0001) Cox regression analysis.
Conclusions: Measurement of mesenchymal CFUs in the BAL provides
predictive information regarding future BOS onset.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91951/1/2011 AJRCCM Mesenchymal stromal cells in bronchoalveolar lavage as predictors of bronchiolitis obliterans syndrome.pd
Protein kinase B controls transcriptional programs that direct cytotoxic T cell fate but is dispensable for T cell metabolism
SummaryIn cytotoxic T cells (CTL), Akt, also known as protein kinase B, is activated by the T cell antigen receptor (TCR) and the cytokine interleukin 2 (IL-2). Akt can control cell metabolism in many cell types but whether this role is important for CTL function has not been determined. Here we have shown that Akt does not mediate IL-2- or TCR-induced cell metabolic responses; rather, this role is assumed by other Akt-related kinases. There is, however, a nonredundant role for sustained and strong activation of Akt in CTL to coordinate the TCR- and IL-2-induced transcriptional programs that control expression of key cytolytic effector molecules, adhesion molecules, and cytokine and chemokine receptors that distinguish effector versus memory and naive T cells. Akt is thus dispensable for metabolism, but the strength and duration of Akt activity dictates the CTL transcriptional program and determines CTL fate
Global defects in collagen secretion in a Mia3/TANGO1 knockout mouse
Mia3’s contribution to protein secretion is broader than previously realized—its absence impairs collagen deposition and normal development of cartilage and bone
Quaternary Structure Defines a Large Class of Amyloid-β Oligomers Neutralized by Sequestration
SummaryThe accumulation of amyloid-β (Aβ) as amyloid fibrils and toxic oligomers is an important step in the development of Alzheimer’s disease (AD). However, there are numerous potentially toxic oligomers and little is known about their neurological effects when generated in the living brain. Here we show that Aβ oligomers can be assigned to one of at least two classes (type 1 and type 2) based on their temporal, spatial, and structural relationships to amyloid fibrils. The type 2 oligomers are related to amyloid fibrils and represent the majority of oligomers generated in vivo, but they remain confined to the vicinity of amyloid plaques and do not impair cognition at levels relevant to AD. Type 1 oligomers are unrelated to amyloid fibrils and may have greater potential to cause global neural dysfunction in AD because they are dispersed. These results refine our understanding of the pathogenicity of Aβ oligomers in vivo
IKK phosphorylates Huntingtin and targets it for degradation by the proteasome and lysosome
Expansion of the polyglutamine repeat within the protein Huntingtin (Htt) causes Huntington's disease, a neurodegenerative disease associated with aging and the accumulation of mutant Htt in diseased neurons. Understanding the mechanisms that influence Htt cellular degradation may target treatments designed to activate mutant Htt clearance pathways. We find that Htt is phosphorylated by the inflammatory kinase IKK, enhancing its normal clearance by the proteasome and lysosome. Phosphorylation of Htt regulates additional post-translational modifications, including Htt ubiquitination, SUMOylation, and acetylation, and increases Htt nuclear localization, cleavage, and clearance mediated by lysosomal-associated membrane protein 2A and Hsc70. We propose that IKK activates mutant Htt clearance until an age-related loss of proteasome/lysosome function promotes accumulation of toxic post-translationally modified mutant Htt. Thus, IKK activation may modulate mutant Htt neurotoxicity depending on the cell's ability to degrade the modified species
Menthol Cigarette Smoking and Obesity in Young Adult Daily Smokers in Hawaii
This study investigates 1) the relationship between menthol cigarette smoking and obesity and 2) the association of body mass index with the nicotine metabolite ratio among menthol and non-menthol daily smokers aged 18–35 (n = 175). A brief survey on smoking and measures of height and weight, carbon monoxide, and saliva samples were collected from participants from May to December 2013 in Honolulu, Hawaii. Multiple regression was used to estimate differences in body mass index among menthol and non-menthol smokers and the association of menthol smoking with obesity. We calculated the log of the nicotine metabolite ratio to examine differences in the nicotine metabolite ratio among normal, overweight, and obese smokers. Sixty-eight percent of smokers used menthol cigarettes. Results showed that 62% of normal, 54% of overweight, and 91% of obese smokers used menthol cigarettes (p = .000). The mean body mass index was significantly higher among menthol compared with non-menthol smokers (29.4 versus 24.5, p = .000). After controlling for gender, marital status, educational attainment, employment status, and race/ethnicity, menthol smokers were more than 3 times as likely as non-menthol smokers to be obese (p = .04). The nicotine metabolite ratio was significantly lower for overweight menthol smokers compared with non-menthol smokers (.16 versus .26, p = .02) in the unadjusted model, but was not significant after adjusting for the covariates. Consistent with prior studies, our data show that menthol smokers are more likely to be obese compared with non-menthol smokers. Future studies are needed to determine how flavored tobacco products influence obesity among smokers
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Copy number variant discrepancy resolution using the ClinGen dosage sensitivity map results in updated clinical interpretations in ClinVar
Conflict resolution in genomic variant interpretation is a critical step toward improving patient care. Evaluating interpretation discrepancies in copy number variants (CNVs) typically involves assessing overlapping genomic content with focus on genes/regions that may be subject to dosage sensitivity (haploinsufficiency (HI) and/or triplosensitivity (TS)). CNVs containing dosage sensitive genes/regions are generally interpreted as â likely pathogenicâ (LP) or â pathogenicâ (P), and CNVs involving the same known dosage sensitive gene(s) should receive the same clinical interpretation. We compared the Clinical Genome Resource (ClinGen) Dosage Map, a publicly available resource documenting known HI and TS genes/regions, against germline, clinical CNV interpretations within the ClinVar database. We identified 251 CNVs overlapping known dosage sensitive genes/regions but not classified as LP or P; these were sent back to their original submitting laboratories for reâ evaluation. Of 246 CNVs reâ evaluated, an updated clinical classification was warranted in 157 cases (63.8%); no change was made to the current classification in 79 cases (32.1%); and 10 cases (4.1%) resulted in other types of updates to ClinVar records. This effort will add curated interpretation data into the public domain and allow laboratories to focus attention on more complex discrepancies.The ClinGen Dosage Sensitivity (DS) Map provides evidenceâ based assessments of the haploinsufficiency and triplosensitivity of genes/genomic regions. We identified 251 clinical copy number variants (CNVs) in ClinVar that overlapped known DS genes/regions but were not interpreted as â likely pathogenicâ or â pathogenic;â these were sent back to their original laboratories for reâ evaluation. Of the 246 that were reâ evaluated, 63.0% resulted in updated classifications, showing that the ClinGen DS Map can be an effective initial step in CNV classification discrepancy resolution.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146425/1/humu23610_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146425/2/humu23610.pd
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Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry.
Importance:Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives:To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants:A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures:Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures:Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data. Results:A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance:In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies
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