Characterization of the Degradation and Conversion of Bone Cement and Borate Bioactive Glass Composites

Periprosthetic infections are a devastating complication of orthopedic procedures, costing time and money as well as the quality of life of affected patients. 13-93B3 is a boron-based bioactive glass that degrades and converts into hydroxyapatite when immersed in a physiological fluid. Its ability to break down and dissolve quickly would be useful for drug delivery when combined with bone cement because this glass can create passages in the cement that would increase the elution of incorporated antibiotics. The conversion of this bioactive glass into calcium phosphate products could also attract surrounding bone growth, further integrating implants with tissue and removing space on the cement surfaces where biofilms can form. While bioactive glasses have previously been added to bone cement, the incorporation of 13-93B3 into commercial bone cement has not yet been reported in literature. The focus of this study was to characterize composites of these materials by measuring its degradation rate and the identity of its resulting precipitate while monitoring for adverse reductions of mechanical strength. Particles of 13-93B3 with diameters of 5 μm, 33 μm, and 100 μm were mixed into a PMMA-based commercial bone cement, DePuy SmartSet MV, to create composites with 20%, 30%, and 40% glass loadings. The composites were formed into pellets and paired with bone cement control groups. These samples were soaked in phosphate-buffered saline (PBS). The compressive strength, Young’s modulus, water uptake, and weight loss of the pellets over time were recorded. The pH and boron concentrations of the solutions were measured at various soak durations. Results showed that smaller glass particles degraded faster in composites than larger particles, and that a higher amount of glass incorporation increased the amount of degradation that occurred. Composites with smaller glass diameters had higher compressive strengths than composites with larger glass particles, though the compressive strengths of all composites were found to be consistently above ASTM F451 and ISO 5833 standards. The conversion of 13-93B3 in the composites was studied using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy – attenuated total reflection (FTIR-ATR), and micro-Raman spectroscopy. The solid precipitate that accumulated on the surfaces was determined to be hydroxyapatite incorporated with magnesium ions from the dissolved glass. The presence of this magnesium in the hydroxyapatite layer could improve the adhesion of the bone cement to living bone. Results from these tests suggest that composites made of 13-93B3 and bone cement may have a promising future in helping to prevent periprosthetic infections and would benefit from further investigation

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Heterozygous Variants in KMT2E Cause a Spectrum of Neurodevelopmental Disorders and Epilepsy.

We delineate a KMT2E-related neurodevelopmental disorder on the basis of 38 individuals in 36 families. This study includes 31 distinct heterozygous variants in KMT2E (28 ascertained from Matchmaker Exchange and three previously reported), and four individuals with chromosome 7q22.2-22.23 microdeletions encompassing KMT2E (one previously reported). Almost all variants occurred de novo, and most were truncating. Most affected individuals with protein-truncating variants presented with mild intellectual disability. One-quarter of individuals met criteria for autism. Additional common features include macrocephaly, hypotonia, functional gastrointestinal abnormalities, and a subtle facial gestalt. Epilepsy was present in about one-fifth of individuals with truncating variants and was responsive to treatment with anti-epileptic medications in almost all. More than 70% of the individuals were male, and expressivity was variable by sex; epilepsy was more common in females and autism more common in males. The four individuals with microdeletions encompassing KMT2E generally presented similarly to those with truncating variants, but the degree of developmental delay was greater. The group of four individuals with missense variants in KMT2E presented with the most severe developmental delays. Epilepsy was present in all individuals with missense variants, often manifesting as treatment-resistant infantile epileptic encephalopathy. Microcephaly was also common in this group. Haploinsufficiency versus gain-of-function or dominant-negative effects specific to these missense variants in KMT2E might explain this divergence in phenotype, but requires independent validation. Disruptive variants in KMT2E are an under-recognized cause of neurodevelopmental abnormalities

Variability in Plus Disease Diagnosis using Single and Serial Images

PurposeTo assess changes in retinopathy of prematurity (ROP) diagnosis in single and serial retinal images.DesignCohort study.ParticipantsCases of ROP recruited from the Imaging and Informatics in Retinopathy of Prematurity (i-ROP) consortium evaluated by 7 graders.MethodsSeven ophthalmologists reviewed both single and 3 consecutive serial retinal images from 15 cases with ROP, and severity was assigned as plus, preplus, or none. Imaging data were acquired during routine ROP screening from 2011 to 2015, and a reference standard diagnosis was established for each image. A secondary analysis was performed using the i-ROP deep learning system to assign a vascular severity score (VSS) to each image, ranging from 1 to 9, with 9 being the most severe disease. This score has been previously demonstrated to correlate with the International Classification of ROP. Mean plus disease severity was calculated by averaging 14 labels per image in serial and single images to decrease noise.Main outcome measuresGrading severity of ROP as defined by plus, preplus, or no ROP.ResultsAssessment of serial retinal images changed the grading severity for > 50% of the graders, although there was wide variability. Cohen's kappa ranged from 0.29 to 1.0, which showed a wide range of agreement from slight to perfect by each grader. Changes in the grading of serial retinal images were noted more commonly in cases of preplus disease. The mean severity in cases with a diagnosis of plus disease and no disease did not change between single and serial images. The ROP VSS demonstrated good correlation with the range of expert classifications of plus disease and overall agreement with the mode class (P = 0.001). The VSS correlated with mean plus disease severity by expert diagnosis (correlation coefficient, 0.89). The more aggressive graders tended to be influenced by serial images to increase the severity of their grading. The VSS also demonstrated agreement with disease progression across serial images, which progressed to preplus and plus disease.ConclusionsClinicians demonstrated variability in ROP diagnosis when presented with both single and serial images. The use of deep learning as a quantitative assessment of plus disease has the potential to standardize ROP diagnosis and treatment