Project description:BackgroundBack pain is a common chief complaint within the United States and is caused by a multitude of etiologies. There are many different treatment modalities for back pain, with a frequent option being spinal fusion procedures. The success of spinal fusion greatly depends on instrumentation, construct design, and bone grafts used in surgery. Bone allografts are important for both structural integrity and providing a scaffold for bone fusion to occur.MethodSearches were performed using terms "allografts" and "bone" as well as product names in peer reviewed literature Pubmed, Google Scholar, FDA-510k approvals, and clinicaltrials.gov.ResultsThis study is a review of allografts and focuses on currently available products and their success in both animal and clinical studies.ConclusionBone grafts used in surgery are generally categorized into 3 main types: autogenous (from patient's own body), allograft (from cadaveric or living donor), and synthetic. This paper focuses on allografts and provides an overview on the different subtypes with an emphasis on recent product development and uses in spinal fusion surgery.
Project description:Laser technologies for fast prototyping using metal powder-based materials allow for faster production of prototype constructions actually used in the tooling industry. This paper presents the results of measurements on the surface texture of flat samples and the surface texture of a prototype of a reduced-mass lathe chuck, made with the additive technology-powder bed fusion. The paper presents an analysis of the impact of samples' orientation on the building platform on the surface geometrical texture parameters (two-dimensional roughness profile parameters (Ra, Rz, Rv, and so on) and spatial parameters (Sa, Sz, and so on). The research results showed that the printing orientation has a very large impact on the quality of the surface texture and that it is possible to set digital models on the building platform (parallel-0° to the building platform plane), allowing for manufacturing models with low roughness parameters. This investigation is especially important for the design and 3D printing of microelectromechanical systems (MEMS) models, where surface texture quality and printable resolution are still a large problem.
Project description:BackgroundThis manuscript is a review of the literature investigating the use of mesenchymal stem cells (MSCs) being applied in the setting of spinal fusion surgery. We mention the rates of pseudarthrosis, discuss current bone grafting options, and examine the preclinical and clinical outcomes of utilizing MSCs to assist in successfully fusing the spine.MethodsA thorough literature review was conducted to look at current and previous preclinical and clinical studies using stem cells for spinal fusion augmentation. Searches for PubMed/MEDLINE and ClinicalTrials.gov through January 2021 were conducted for literature mentioning stem cells and spinal fusion.ResultsAll preclinical and clinical studies investigating MSC use in spinal fusion were examined. We found 19 preclinical and 17 clinical studies. The majority of studies, both preclinical and clinical, were heterogeneous in design due to different osteoconductive scaffolds, cells, and techniques used. Preclinical studies showed promising outcomes in animal models when using appropriate osteoconductive scaffolds and factors for osteogenic differentiation. Similarly, clinical studies have promising outcomes but differ in their methodologies, surgical techniques, and materials used, making it difficult to adequately compare between the studies.ConclusionMSCs may be a promising option to use to augment grafting for spinal fusion surgery. MSCs must be used with appropriate osteoconductive scaffolds. Cell-based allografts and the optimization of their use have yet to be fully elucidated. Further studies are necessary to determine the efficacy of MSCs with different osteoconductive scaffolds and growth/osteogenic differentiation factors.Level of evidence3.
Project description:The biologic steps involved in creating a bony fusion between adjacent segments of the spine are a complex and highly coordinated series of events. There have been significant advancements in bone grafts and bone graft substitutes in order to augment spinal fusion. While autologous bone grafting remains the gold standard, allograft bone grafting, synthetic bone graft substitutes, and bone graft enhancers are appropriate in certain clinical situations. This article provides an overview of the basic biology of spinal fusion and strategies for enhancing fusion through innovations in bone graft material.
Project description:Gene expression profiling provides powerful analyses of transcriptional responses to cellular perturbation. In contrast to DNA array-based methods, reporter gene technology has been underused for this application. Here we describe a genomewide, genome-registered collection of Escherichia coli bioluminescent reporter gene fusions. DNA sequences from plasmid-borne, random fusions of E. coli chromosomal DNA to a Photorhabdus luminescens luxCDABE reporter allowed precise mapping of each fusion. The utility of this collection covering about 30% of the transcriptional units was tested by analyzing individual fusions representative of heat shock, SOS, OxyR, SoxRS, and cya/crp stress-responsive regulons. Each fusion strain responded as anticipated to environmental conditions known to activate the corresponding regulatory circuit. Thus, the collection mirrors E. coli's transcriptional wiring diagram. This genomewide collection of gene fusions provides an independent test of results from other gene expression analyses. Accordingly, a DNA microarray-based analysis of mitomycin C-treated E. coli indicated elevated expression of expected and unanticipated genes. Selected luxCDABE fusions corresponding to these up-regulated genes were used to confirm or contradict the DNA microarray results. The power of partnering gene fusion and DNA microarray technology to discover promoters and define operons was demonstrated when data from both suggested that a cluster of 20 genes encoding production of type I extracellular polysaccharide in E. coli form a single operon.
Project description:The paper presents the results of tests aimed at evaluating the surface textures of samples manufactured from material based on 316L stainless steel. The analysis of the surface topography was conducted based on the classical approach in accordance with the current standard and with the use of multiscale methods; i.e., wavelet transformation and geometric via curvature. Selective laser melting 3D printing technology was used to produce samples for surface testing. Furthermore, additional assessment of surfaces created as result of milling was conducted. Statistical research demonstrated a differentiation in the distribution of particular morphological features in certain ranges of the analyzed scales.
Project description:Whitlockite (WH) is the second most abundant inorganic component of human bone, accounting for approximately 25% of bone tissue. This study investigated the role of WH in bone remodeling and formation in a mouse spinal fusion model. Specifically, morphology and composition analysis, tests of porosity and surface area, thermogravimetric analysis, an ion-release test, and a cell viability test were conducted to analyze the properties of bone substitutes. The MagOss group received WH, Group A received 100% beta-tricalcium phosphate (β-TCP), Group B received 100% hydroxyapatite (HAp), Group C received 30% HAp/70% β-TCP, and Group D received 60% HAp/40% β-TCP (n = 10 each). All mice were sacrificed 6 weeks after implantation, and micro-CT, hematoxylin and eosin (HE) staining, and Masson trichome (MT) staining and immunohistochemistry were performed. The MagOss group showed more homogeneous and smaller grains, and nanopores (<500 nm) were found in only the MagOss group. On micro-CT, the MagOss group showed larger fusion mass and better graft incorporation into the decorticate mouse spine than other groups. In the in vivo experiment with HE staining, the MagOss group showed the highest new bone area (mean: decortication group, 9.50%; A, 15.08%; B, 15.70%; C, 14.76%; D, 14.70%; MagOss, 22.69%; p < 0.0001). In MT staining, the MagOss group demonstrated the highest new bone area (mean: decortication group, 15.62%; A, 21.41%; B, 22.86%; C, 23.07%; D, 22.47%; MagOss, 26.29%; p < 0.0001). In an immunohistochemical analysis for osteocalcin, osteopontin, and CD31, the MagOss group showed a higher positive area than other groups. WH showed comparable bone conductivity to HAp and β-TCP and increased new bone formation. WH is likely to be used as an improved bone substitute with better bone conductivity than HAp and β-TCP.
Project description:BackgroundSpinal cord ischemic injury is a severe complication of aortic surgery. We hypothesized that cerebrospinal fluid (CSF) oxygenation with nanobubbles after reperfusion could ameliorate spinal cord ischemic injury.MethodsTwenty white Japanese rabbits were categorized into 4 groups of 5 rabbits each: sham group, with balloon catheter insertion into the aorta; ischemia group, with spinal cord ischemic injury by abdominal aortic occlusion; nonoxygenated group, with nonoxygenated artificial CSF irrigation after spinal cord ischemic injury; and oxygenated group, with oxygenated artificial CSF irrigation after spinal cord ischemic injury. At 48 hours after spinal cord ischemic injury, the modified Tarlov score to reflect hind limb movement was evaluated. The spinal cord was histopathologically examined by counting anterior horn cells, and microarray and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analyses were performed.ResultsThe oxygenated group showed improved neurologic function compared with the ischemia and nonoxygenated groups (P < .01 and P = .019, respectively). Anterior horn neuron prevention in the sham, nonoxygenated, and oxygenated groups was confirmed (mean modified Tarlov score: sham, 9.2 ± 1.9; nonoxygenated, 10.2 ± 2.2; oxygenated, 10.4 ± 2.2; ischemia, 2.7 ± 2.7). Microarray analysis identified 644 genes with twofold or greater increased signals between the ischemia and sham groups. Thirty-three genes related to inflammatory response were enriched among genes differentially expressed between the oxygenated and ischemia groups. Interleukin (IL)-6 and tumor necrosis factor (TNF) expression levels were significantly lower in the oxygenated group compared with the ischemia group, while qRT-PCR showed lower IL-6 and TNF expression levels in the oxygenated group compared with the ischemia group (P < .05).ConclusionsCSF oxygenation with nanobubbles after reperfusion can ameliorate spinal cord ischemic injury and suppress inflammatory responses in the spinal cord.
Project description:Melatonin is probably produced in all cells but is only secreted by the pineal gland. The pineal secretion of melatonin is determined by the light-dark cycle, and it is only released at night. Melatonin regulates biological rhythms via its receptors located in the suprachiasmatic nuclei of the hypothalamus. Melatonin also has strong antioxidant activities to scavenge free radicals such as reactive oxygen species (ROS). The direct free radical scavenging actions are receptor independent. ROS play an important role in reproductive function including in the ovulatory process. However, excessive ROS can also have an adverse effect on oocytes because of oxidative stress, thereby causing infertility. It is becoming clear that melatonin is located in the ovarian follicular fluid and in the oocytes themselves, which protects these cells from oxidative damage as well as having other beneficial actions in oocyte maturation, fertilization, and embryo development. Trials on humans have investigated the improvement of outcomes of assisted reproductive technology (ART), such as in vitro fertilization and embryo transfer (IVF-ET), by way of administering melatonin to patients suffering from infertility. In addition, clinical research has examined melatonin as an anti-aging molecule via its antioxidative actions, and its relationship with the aging diseases, e.g., Alzheimer's and Parkinson's disease, is also underway. Melatonin may also reduce ovarian aging, which is a major issue in assisted reproductive technology. This review explains the relationship between melatonin and human reproductive function, as well as the clinical applications expected to improve the outcomes of assisted reproductive technology such as IVF, while also discussing possibilities for melatonin in preventing ovarian aging.