43 research outputs found

    Orbital Observations of Dust Lofted by Daytime Convective Turbulence

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    Over the past several decades, orbital observations of lofted dust have revealed the importance of mineral aerosols as a climate forcing mechanism on both Earth and Mars. Increasingly detailed and diverse data sets have provided an ever-improving understanding of dust sources, transport pathways, and sinks on both planets, but the role of dust in modulating atmospheric processes is complex and not always well understood. We present a review of orbital observations of entrained dust on Earth and Mars, particularly that produced by the dust-laden structures produced by daytime convective turbulence called “dust devils”. On Earth, dust devils are thought to contribute only a small fraction of the atmospheric dust budget; accordingly, there are not yet any published accounts of their occurrence from orbit. In contrast, dust devils on Mars are thought to account for several tens of percent of the planet’s atmospheric dust budget; the literature regarding martian dust devils is quite rich. Because terrestrial dust devils may temporarily contribute significantly to local dust loading and lowered air quality, we suggest that martian dust devil studies may inform future studies of convectively-lofted dust on Earth

    Multi-ancestry genome-wide association analyses improve resolution of genes and pathways influencing lung function and chronic obstructive pulmonary disease risk.

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    Lung-function impairment underlies chronic obstructive pulmonary disease (COPD) and predicts mortality. In the largest multi-ancestry genome-wide association meta-analysis of lung function to date, comprising 580,869 participants, we identified 1,020 independent association signals implicating 559 genes supported by ≥2 criteria from a systematic variant-to-gene mapping framework. These genes were enriched in 29 pathways. Individual variants showed heterogeneity across ancestries, age and smoking groups, and collectively as a genetic risk score showed strong association with COPD across ancestry groups. We undertook phenome-wide association studies for selected associated variants as well as trait and pathway-specific genetic risk scores to infer possible consequences of intervening in pathways underlying lung function. We highlight new putative causal variants, genes, proteins and pathways, including those targeted by existing drugs. These findings bring us closer to understanding the mechanisms underlying lung function and COPD, and should inform functional genomics experiments and potentially future COPD therapies

    Arthroscopic Labral Reconstruction of the Hip Using Local Capsular Autograft

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    Labral reconstruction is becoming an important treatment modality for hips with nonsalvageable labra. Nonsalvageable labra can be present in cases of intrasubstance damage, revision surgery after debridement, labral calcification, and hypoplasia. Previous methods of reconstruction have been performed in an open manner and arthroscopically using ligamentum teres, iliotibial band, and gracilis autograft. We present an alternate method of arthroscopic labral reconstruction using capsular autograft. The technique uses readily available capsular tissue during arthroscopy with no donor-site morbidity. This technique may be valuable in appropriately selected patients with labral deficiency

    Endoscopic Pubic Symphysectomy for Recalcitrant Osteitis Pubis

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    Recalcitrant osteitis pubis presents a challenging problem for orthopaedic surgeons. Various surgical interventions have been described for treatment, including opening-wedge resection, symphysiodesis, and curettage. We propose that endoscopic pubic symphysectomy offers an effective method of treating such a challenging problem. This article describes in detail the technique used to perform endoscopic pubic symphysectomy, and a companion video demonstrating the procedure is included. Our experience suggests that removal of the interpubic fibrocartilaginous lamina and resection of approximately 1 cm of bone can successfully eliminate all sources of pain and dysfunction caused by the recalcitrant osteitis pubis

    Utilising silk fibroin membranes as scaffolds for the growth of tympanic membrane keratinocytes, and application to myringoplasty surgery

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    Background: Chronic tympanic membrane perforations can cause significant morbidity. The term myringoplasty describes the operation used to close such perforations. A variety of graft materials are available for use in myringoplasty, but all have limitations and few studies report post-operative hearing outcomes. Recently, the biomedical applications of silk fibroin protein have been studied. This material’s biocompatibility, biodegradability and ability to act as a scaffold to support cell growth prompted an investigation of its interaction with human tympanic membrane keratinocytes. Methods and materials: Silk fibroin membranes were prepared and human tympanic membrane keratinocytes cultured. Keratinocytes were seeded onto the membranes and immunostained for a number of relevant protein markers relating to cell proliferation, adhesion and specific epithelial differentiation. Results: The silk fibroin scaffolds successfully supported the growth and adhesion of keratinocytes, whilst also maintaining their cell lineage. Conclusion: The properties of silk fibroin make it an attractive option for further research, as a potential alternative graft in myringoplasty

    Arthroscopic Decompression of Central Acetabular Impingement With Notchplasty

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    Acetabular notch osteophytes are often encountered during routine diagnostic arthroscopy of the hip. It has been our observation that when notch osteophytes are present, there is often corresponding chondral damage to the anterosuperior femoral head and ligamentum teres degeneration. We propose that removal of the notch osteophyte and decompression of the articulating surface offer an effective method of delaying the progression of arthritis. This article describes in detail the technique used to perform arthroscopic acetabular notchplasty, and a companion video, demonstrating the procedure, is included. Our experience suggests that decompression of the acetabular notch can remove offending structural abnormalities that can potentially cause further chondral damage and may hasten the progression of arthritis

    Trochanteric Micropuncture: Treatment for Gluteus Medius Tendinopathy

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    Lateral hip pain along with tenderness of the greater trochanter has been associated with greater trochanteric pain syndrome. Radiographically, this has been associated with gluteus medius pathology on magnetic resonance imaging. This has led some surgeons to conclude that abductor pathology is a primary cause of lateral hip pain. Failure of conservative treatment in the setting of gluteus medius pathology may lead to surgical intervention. In some patients a focal tear of the gluteus medius cannot be visualized and likely represents more diffuse tendinopathy. In these patients we propose micropuncture of the greater trochanter. Similar procedures have shown effectiveness in the elbow and shoulder by eliciting a healing response. Our experience suggests that trochanteric micropuncture at the insertion of the gluteus medius tendon can be effectively performed endoscopically for gluteus medius tendinopathy

    Arthroscopic Labral Reconstruction of the Hip Using Semitendinosus Allograft

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    The labrum of the hip is recognized as being important to the stability of the hip and a major cause of hip pain. Damage to the labrum may result in increased joint stress and articular damage. Labral damage is often treated through various methods, among them simple stitch repair, base refixation, and debridement. Labral reconstruction becomes necessary when the labrum is too damaged to salvage, which renders labral repair improbable and labral debridement ineffective. In contrast to other methods that have been described for this treatment, our technique uses a semitendinosus allograft as a graft source, allowing for arthroscopic hip labral reconstruction. This technique has many advantages and is easily reproducible. It has shown promising results in patients with labral damage. The purpose of this article is to detail the step-by-step surgical technique of labral reconstruction using a semitendinosus allograft, in addition to the indications, pearls, and pitfalls of the technique

    Paracrine Activity from Adipose-Derived Stem Cells on In Vitro Wound Healing in Human Tympanic Membrane Keratinocytes

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    Stem cell therapies for tympanic membrane repair have shown initial experimental success using mesenchymal stem cells in rat models to promote healing; however, the mechanisms providing this benefit are not known. We investigated in vitro the paracrine effects of human adipose-derived stem cells (ADSCs) on wound healing mechanisms for human tympanic membrane-derived keratinocytes (hTM) and immortalized human keratinocytes (HaCaT). ADSC conditioned media (CMADSC) were assessed for paracrine activity on keratinocyte proliferation and migration, with hypoxic conditions for ADSC culture used to generate contrasting effects on cytokine gene expression. Keratinocytes cultured in CMADSC showed a significant increase in cell number compared to serum-free cultures and further significant increases in hypoxic CMADSC. Assessment of ADSC gene expression on a cytokine array showed a range of wound healing cytokines expressed and under stringent hypoxic and serum-free conditions was upregulated (VEGF A, MMP9, Tissue Factor, PAI-1) or downregulated (CXCL5, CCL7, TNF-α). Several of these may contribute to the activity of conditioned media on the keratinocytes with potential applications in TM perforation repair. VEGFA protein was confirmed by immunoassay to be increased in conditioned media. Together with gene regulation associated with hypoxia in ADSCs, this study has provided several strong leads for a stem cell-derived approach to TM wound healing
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