Publications by authors named "Tracy Hopkins"

In vivo use of biodegradable magnesium (Mg) metal can be plagued by too rapid a degradation rate that removes metal support before physiological function is repaired. To advance the use of Mg biomedical implants, the degradation rate may need to be adjusted. We previously demonstrated that pure Mg filaments used in a nerve repair scaffold were compatible with regenerating peripheral nerve tissues, reduced inflammation, and improved axonal numbers across a short-but not long-gap in sciatic nerves in rats.

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  • Traumatic brain injury (TBI) affects over 69 million people globally each year, and individuals with prior depression tend to recover worse.
  • The study used WKY rats to investigate how TBI impacts recovery, particularly focusing on changes in the hippocampus and comparing it to regular Wistar rats.
  • Findings revealed that WKY rats experienced greater myelin loss and had pre-existing deficits in brain cell proliferation, highlighting the unique molecular factors that hinder recovery after TBI in those with depression, which could inform future treatments.
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Magnesium (Mg) metal is of great interest in biomedical applications, especially in tissue engineering. Mg exhibits excellent in vivo biocompatibility, biodegradability and, during degradation, releases Mg ions (Mg) with the potential to improve tissue repair. We used electrospinning technology to incorporate Mg particles into nanofibers.

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Absorbable implants made of magnesium alloys may revolutionize surgical intervention, and fine magnesium wire will be critical to many applications. Functionally, the wires must have sufficient mechanical properties to withstand implantation and in-service loading, have excellent tissue tolerance, and exhibit an appropriate degradation rate for the application. Alloy chemistry and thermomechanical processing conditions will significantly impact the material's functional performance, but the exact translation of these parameters to implant performance is unclear.

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  • Hollow nerve conduits made from biomaterials, used to help heal damaged peripheral nerves, need to maintain their structure during recovery, leading to exploration of new methods for studying their integrity.
  • A combined approach utilizing micro-CT imaging and histological analysis was employed to assess two types of nerve conduits in rats after nerve reconstruction, revealing varying structural outcomes.
  • Results indicated that while poly(caprolactone) conduits experienced significant breakage, they still supported nerve growth; silicone conduits remained intact but showed constriction, illustrating that nerve regeneration can occur despite limitations in conduit integrity.
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  • A study explored the use of biodegradable magnesium filaments within nerve conduits to replace autografts for repairing peripheral nerve injuries in adult rats.
  • Results showed that magnesium filaments supported nerve repair, with better axon growth compared to empty conduits or those with titanium filaments, especially after a 6 mm gap and 6 weeks post-repair.
  • Despite less improvement in nerve regeneration with longer gaps (15 mm) and more time (16 weeks), magnesium filaments demonstrated biocompatibility and enhanced tissue conditions compared to empty conduits, making them a promising option for future nerve repair strategies.
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Background Poly(butylcyanoacrylate) (PBCA) nanoparticles (NPs) loaded with doxorubicin (DOX) and coated with polysorbate 80 (PS80) have shown efficacy in the treatment of rat glioblastoma. However, cytotoxicity of this treatment remains unclear. Purpose The purpose of this study was to investigate cytotoxicity and apoptotic gene expression using a proven in vitro co-culture model of the blood-brain barrier.

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Background: Biomedical implants used in tissue engineering repairs, such as scaffolds to repair peripheral nerves, can be too large to examine completely with histological analyses. Micro-computed tomography (micro-CT) with contrast agents allows ex vivo visualization of entire biomaterial implants and their interactions with tissues, but contrast agents can interfere with histological analyses of the tissues or cause shrinkage or loss of antigenicity.

New Method: Soft tissue, ex vivo micro-CT imaging using Lugol's iodine was compatible with histology after using a rapid (48 h) method of removing iodine.

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Carbon nanotubes (CNTs) are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing.

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Because a potential treatment for brain injuries could be elevating magnesium ions (Mg(2+)) intracerebrally, we characterized the effects of elevating external Mg(2+) in cultures of neonatal murine brain-derived neural stem/progenitor cells (NSCs). Using a crystal violet assay, which avoids interference of Mg(2+) in the assay, it was determined that substrate influenced Mg(2+) effects on cell numbers. On uncoated plastic, elevating Mg(2+) levels to between 2.

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Keratin-based composite nanofibers have been fabricated by an electrospinning technique. Aqueous soluble keratin extracted from human hair was successfully blended with poly(ε-caprolactone) (PCL) in different ratios and transformed into nanofibrous membranes. Toward the potential use of this nanofibrous membrane in tissue engineering, its physicochemical properties, such as morphology, mechanical strength, crystallinity, chemical structure, and integrity in aqueous medium were studied and its cellular compatibility was determined.

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Increased neurogenesis in the hippocampus and subventricular zone (SVZ) of the brain of animals has been demonstrated following administration of several psychotropic medications. Such changes are thought to regenerate tissues and contribute to the beneficial effects of the medications. This study sought to determine if another neurogenic tissue, the peripheral olfactory epithelium (OE), might also exhibit changes after treatment with psychotropic medications.

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This paper reports interim findings of a prospective study that examines longitudinal outcomes of early- and later-identified children with hearing impairment in Australia. Eighty-seven children with cochlear implants were assessed using the Preschool Language Scale at one or more intervals. Results demonstrated that children who received a cochlear implant before 12 months of age developed normal language skills and at a rate that is comparable to normal-hearing children.

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