Publications by authors named "Ashlyn G Rickard"

Introduction: Immune dysregulation plays a major role in cancer progression. The quantification of lymphocytic spatial inflammation may enable spatial system biology, improve understanding of therapeutic resistance, and contribute to prognostic imaging biomarkers.

Methods: In this paper, we propose a knowledge-guided deep learning framework to measure the lymphocytic spatial architecture on human H&E tissue, where the fidelity of training labels is maximized through single-cell resolution image registration of H&E to IHC.

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Purpose: Despite aggressive multimodal treatment that typically includes definitive or adjuvant radiation therapy (RT), locoregional recurrence rates approach 50% for patients with locally advanced human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC). Thus, more effective therapeutics are needed to improve patient outcomes. We evaluated the radiosensitizing effects of ataxia telangiectasia and RAD3-related (ATR) inhibitor (ATRi) BAY 1895344 in preclinical models of HNSCC.

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Article Synopsis
  • Tumor hypoxia significantly reduces the effectiveness of radiation therapy, with areas of low oxygen being three times less responsive to treatment than areas with normal oxygen levels.
  • This study employed a specialized imaging technique called electron paramagnetic resonance oxygen-imager (EPROI) to measure tumor oxygen levels in two mouse tumor models, revealing that the sarcoma model more accurately reflects human tumors.
  • Results showed that the high levels of hypoxia in sarcomas make them more resistant to radiation, and treatment with the mitochondrial inhibitor papaverine did not enhance radiosensitivity in either tumor model.*
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Inflammatory breast cancer (IBC), an understudied and lethal breast cancer, is often misdiagnosed due to its unique presentation of diffuse tumor cell clusters in the skin and dermal lymphatics. Here, we describe a window chamber technique in combination with a novel transgenic mouse model that has red fluorescent lymphatics (ProxTom RFP Nu/Nu) to simulate IBC clinicopathological hallmarks. Various breast cancer cells stably transfected to express green or red fluorescent reporters were transplanted into mice bearing dorsal skinfold window chambers.

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Diffuse reflectance spectroscopy (DRS) is a powerful tool for quantifying optical and physiological tissue properties such as hemoglobin oxygen saturation and vascularity. DRS is increasingly used clinically for distinguishing cancerous lesions from normal tissue. However, its widespread clinical acceptance is still limited due to uncontrolled probe-tissue interface pressure that influences reproducibility and introduces operator-dependent results.

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Intracellular oxygenation is an important parameter for numerous biological studies. While there are a variety of methods available for acquiring measurements of oxygenation in animal models, most are dependent on indirect oxygen measurements, restraints, or anesthetization. A portable microscope system using a Raspberry Pi computer and Pi Camera was developed for attaching to murine dorsal window chambers.

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Significance: Decreasing the oxygen consumption rate (OCR) of tumor cells is a powerful method for ameliorating tumor hypoxia. However, quantifying the change in OCR is challenging in complex experimental systems.

Aim: We present a method for quantifying the OCR of two tumor cell lines using oxygen-sensitive dual-emissive boron nanoparticles (BNPs).

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Purpose: Real-time monitoring of physiological changes of tumor tissue during radiation therapy (RT) could improve therapeutic efficacy and predict therapeutic outcomes. Cherenkov radiation is a normal byproduct of radiation deposited in tissue. Previous studies in rat tumors have confirmed a correlation between Cherenkov emission spectra and optical measurements of blood-oxygen saturation based on the tissue absorption coefficients.

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Hypoxia, a prevalent characteristic of most solid malignant tumors, contributes to diminished therapeutic responses and more aggressive phenotypes. The term hypoxia has two definitions. One definition would be a physiologic state where the oxygen partial pressure is below the normal physiologic range.

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The increased expression of vascular endothelial growth factor (VEGF) and its receptors is associated with angiogenesis in a growing tumor, presenting potential targets for tumor-selective imaging by way of targeted tracers. Though fluorescent tracers are used for targeted in vivo imaging, the lack of photostability and biocompatibility of many current fluorophores hinder their use in several applications involving long-term, continuous imaging. To address these problems, fluorescent nanodiamonds (FNDs), which exhibit infinite photostability and excellent biocompatibility, were explored as fluorophores in tracers for targeting VEGF receptors in growing tumors.

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