Neurodegenerative diseases are currently among the most common causes for low quality of life among US population. In addition to that, disabilities caused by neurodegenerative diseases, negatively impact economy by causing early workforce retirement. Existing human models of such conditions are hard to replicate and describe due to the wide array of factors influencing the progression and morphology of the disease. Recent studies suggest application of photodynamically induced oxidative stress in drosophila model as a viable trigger to neurodegenerative conditions. We hypothesize that neural degradation is accompanied by significant changes in brain chemistry and biomechanics. This preliminary study focuses on investigation of correlation between drosophila brain elasticity and induced oxidative stress using combined Brillouin-Raman spectroscopy as a label-free method of elasticity measurement.
Implant infections pose a serious health risk to patients, both immediately after surgery and even years later. Hard materials provide the opportunity for more potent infection clearing, but soft materials like hydrogels are more delicate and may be more susceptible to the formation of sturdy bacterial biofilms. Photodynamic therapy (PDT) is a proven technique for infectious load reduction, biofilm penetration, and sensitization to antibiotic therapies. However, evaluation is lacking in efficacy of PDT in proximity to hydrogels, based on the risks of oxidative degradation. This preliminary study assesses the effects of PDT on HEMA-DMAEMA hydrogel viscoelastic properties. PDT is applied by soaking of hydrogels in PBS containing 10 ฮผM methylene blue and subsequent 660 nm light exposure at 9.20 ๐๐/๐๐2 for 30 minutes. PDT and all component controls cause reduction in values of storage modulus, loss modulus, and loss factor, but only differences in storage modulus are statistically significant as compared to baseline controls. Additionally, PDT component controls are comparable to the PDT test group, implying that photosensitizer integration and light degradation of hydrogels may be the primary source of interference. Overall, the changes noted in viscoelasticity are moderate and encourage further exploration with larger PDT doses, greater sample numbers, and testing of commercially available implant materials.
Antimicrobial photodynamic therapy (aPDT) in combination with antibiotics leads to a notable reduction in antibiotic minimum inhibitory concentration (MIC). Four antibiotic resistant bacterial strains (E. faecalis OG1RF(+), P. aeruginosa PA01, K. pneumoniae, E. coli ETEC) were evaluated with four antibiotics (ampicillin, kanamycin, tetracycline, chloramphenicol) in a combination treatment with methylene blue aPDT. Treatment involved co-culture of antibiotics with 1.0 μ๐ MB followed by exposure to 0 to 14.4 ๐ฝ๐๐2 of light over 0 to 10 minutes at a rate of 30 ๐๐๐๐2. MIC of test groups was compared to controls to evaluate direct effects on resistance, and further aPDT controls were used to evaluate measures of synergistic effect based on fractional inhibitory concentration index (FICI). It was found that 12 of 16 strain-antibiotic combinations have a reduction in antibiotic resistance during treatment, two of which are statistically significant. The calculated FICI values for these combinations contain 6 indifferent values between 1.0 and 1.5 and 10 additive values at or below 1.0, one of which was 0.43, qualifying as synergistic treatment. Overall, this survey provides a brief exploration of aPDT as an adjunct therapy for combatting antibiotic resistant bacteria. Further targeted research on strain-antibiotic combinations of interest may reveal valuable synergistic effects.
Photosensitizer uptake and elimination are studied in the animal model D. melanogaster with the purpose of developing tools for highly regulated photodynamic therapy (PDT) as a model of accelerated aging and neurodegenerative disorders. The photosensitizer (PS) methylene blue (MB) is given in a concentration of 1 mM by mixing with growth media for fly consumption. Internal MB increases for eight hours following exposure to MB media. At this time, the mean trends of these early results show adequate uptake rate and maximum internal MB for PDT utility in the D. melanogaster model and potential for further applications in disease modelling.
Photodynamic inactivation (PDI) has been widely applied to localized infections, both internal and external. However, there is a notable knowledge gap when it comes to applying PDI to an entire organ system or even systemically throughout an organism. To study these treatment methods, an in vivo murine model of MHV-1 is planned. As a respiratory coronavirus, the model provides a suitable system for study, in addition to potential determination of systemic results. Specifically applied, MHV-1 has many key characteristics, such as symptoms and viral protein structures, that are in common or similar to other coronaviruses. Thus, this theorized model simultaneously addresses a key knowledge gap and provides useful insights into potential treatments for COVID-19 and similar disease-causing viruses. The risk of emergent viral threats and the necessity for rapidly developed, adaptable, affordable treatment methods are both now vividly evident.
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