Scaffold-free development of multicellular tumor spheroids with spatial characterization of structure and metabolic radial profiles.

Purpose: assays are essential for studying cellular biology, but traditional monolayer cultures fail to replicate the complex three-dimensional (3D) interactions of cells in living organisms. 3D culture systems offer a more accurate reflection of the cellular microenvironment. However, 3D cultures require robust and unique methods of characterization.

The Physiological and Therapeutic Role of CD47 in Macrophage Function and Cancer.

Background: Immunotherapy is an emerging strategy in cancer therapeutics aimed at modulating the immune system to inhibit pro-tumor pathways and increase a tumor's sensitivity to chemotherapy. Several clinically approved immunotherapy treatments, such as monoclonal antibody treatments, have been successful in solid tumors such as breast, colorectal, and pancreatic. However, an outstanding challenge of these strategies is tumor cell resistance.

Live-Cell Imaging Quantifies Changes in Function and Metabolic NADH Autofluorescence During Macrophage-Mediated Phagocytosis of Tumor Cells.

Background: The immune system has evolved to detect foreign antigens and deliver coordinated responses, while minimizing "friendly fire." Until recently, studies investigating the behavior of immune cells were limited to static measurements. Although static measurements allow for real-time imaging, results are often difficult to translate to an setting.

Autofluorescence imaging of endogenous metabolic cofactors in response to cytokine stimulation of classically activated macrophages.

Background: Macrophages are one of the most prevalent subsets of immune cells within the tumor microenvironment and perform a range of functions depending on the cytokines and chemokines released by surrounding cells and tissues. Recent research has revealed that macrophages can exhibit a spectrum of phenotypes, making them highly plastic due to their ability to alter their physiology in response to environmental cues. Recent advances in examining heterogeneous macrophage populations include optical metabolic imaging, such as fluorescence lifetime imaging (FLIM), and multiphoton microscopy.

Longitudinal examination of perfusion and angiogenesis markers in primary colorectal tumors shows distinct signatures for metronomic and maximum-tolerated dose strategies.

Metronomic chemotherapy (MET) has been developed to address the shortcomings of maximum-tolerated chemotherapy (MTD) in regard to toxicity and development of resistance mechanisms in the tumor. In colorectal cancer (CRC), MET is a promising novel strategy to treat locally advanced malignancies when used as neoadjuvant chemotherapy (NAC). However, so far there are no preclinical studies to assess the impact of MET NAC in CRC to assess the benefits and challenges of this approach.

"Persistence of Memory" - Multimodal imaging of delayed sympathetic ophthalmia.

Purpose: To describe a case of late post-surgical sympathetic ophthalmia documented with multimodal imaging.

Observations: A 74-year-old male presented to the urgent care of the New York Eye and Ear Infirmary with blurry vision and discomfort in his left eye for three weeks. His vision was 20/50, with intraocular pressure of 13 mmHg, and slit lamp examination was significant for conjunctival congestion, 1+ anterior segment cell and flare, and diffuse keratic precipitates.

Generalized additive models to analyze nonlinear trends in biomedical longitudinal data using R: Beyond repeated measures ANOVA and linear mixed models.

In biomedical research, the outcome of longitudinal studies has been traditionally analyzed using the repeated measures analysis of variance (rm-ANOVA) or more recently, linear mixed models (LMEMs). Although LMEMs are less restrictive than rm-ANOVA as they can work with unbalanced data and non-constant correlation between observations, both methodologies assume a linear trend in the measured response. It is common in biomedical research that the true trend response is nonlinear and in these cases the linearity assumption of rm-ANOVA and LMEMs can lead to biased estimates and unreliable inference.

Minimally invasive endoscopic monitoring of dextran sulfate sodium-induced murine colitis.

Ulcerative colitis (UC) is a gastrointestinal, autoimmune disease that causes ulceration and inflammation of the colon with an incidence of 10 out of every 100,000 people in North America and Western Europe. Though the specific cause is unknown, several studies have demonstrated that inflammatory cells as well as environmental variables, genetics, and lifestyle behaviors can play a role in the long-term inflammatory response. Researchers have commonly used immunohistochemistry, western blotting and gene sequencing to establish the cellular processes behind UC relapse and remission.

Macrophage-targeted anti-CCL2 immunotherapy enhances tumor sensitivity to 5-fluorouracil in a Balb/c-CT26 murine colon carcinoma model measured using diffuse reflectance spectroscopy.

Background: Immunotherapy in colorectal cancer (CRC) regulates specific immune checkpoints and, when used in combination with chemotherapy, can improve patient prognosis. One specific immune checkpoint is the recruitment of circulating monocytes that differentiate into tumor-associated macrophages (TAMs) and promote tumor angiogenesis. Changes in vascularization can be non-invasively assessed via diffuse reflectance spectroscopy using hemoglobin concentrations and oxygenation in a localized tumor volume.

Employing Faculty, Peer Mentoring, and Coaching to Increase the Self-Confidence and Belongingness of First-Generation College Students in Biomedical Engineering.

First-generation college students (FGCSs) face myriad challenges including the lack of parental guidance, economic and social burdens, isolation, decreased belongingness, and lowered self-confidence making them at an increased risk of dropping out of college compared to their continuing-generation college students colleagues. In addition, being in a multidisciplinary science, technology, engineering, and mathematics (STEM) field such as biomedical engineering (BMEG) is another challenge as it requires the integration of several disciplines. This study aims to maximize FGCSs' success and retention in BMEG.

A Light-Sheet-Based Imaaging Spectrometer to Characterize Acridine Orange Fluorescence within Leukocytes.

Low-cost imaging systems that utilize exogenous fluorescent dyes, such as acridine orange (AO), have recently been developed for use as point-of-care (POC) blood analyzers. AO-based fluorescence imaging exploits variations in emission wavelength within different cell types to enumerate and classify leukocyte subpopulations from whole blood specimens. This approach to leukocyte classification relies on accurate and reproducible colorimetric features, which have previously been demonstrated to be highly dependent on the cell staining protocols (such as specific AO concentration, timing, and pH).

Label-free optical biomarkers detect early calcific aortic valve disease in a wild-type mouse model.

Background: Calcific aortic valve disease (CAVD) pathophysiology is a complex, multistage process, usually diagnosed at advanced stages after significant anatomical and hemodynamic changes in the valve. Early detection of disease progression is thus pivotal in the development of prevention and mitigation strategies. In this study, we developed a diet-based, non-genetically modified mouse model for early CAVD progression, and explored the utility of two-photon excited fluorescence (TPEF) microscopy for early detection of CAVD progression.

Diffuse reflectance spectroscopy to monitor murine colorectal tumor progression and therapeutic response (Erratum).

The erratum notes a correction to Fig. 5 for the published article.

Diffuse reflectance spectroscopy to monitor murine colorectal tumor progression and therapeutic response.

Significance: Many studies in colorectal cancer (CRC) use murine ectopic tumor models to determine response to treatment. However, these models do not replicate the tumor microenvironment of CRC. Physiological information of treatment response derived via diffuse reflectance spectroscopy (DRS) from murine primary CRC tumors provide a better understanding for the development of new drugs and dosing strategies in CRC.

Efficacy and clinical monitoring strategies for immune checkpoint inhibitors and targeted cytokine immunotherapy for locally advanced and metastatic colorectal cancer.

Colorectal cancer (CRC) is the fourth most common cancer type and is the second leading cause of cancer deaths annually in the United States. Conventional treatment options include postoperative (adjuvant) and preoperative (neoadjuvant) chemotherapy and radiotherapy. Although these treatment modalities have shown to decrease tumor burden, a major limitation to chemothearpy/radiotherapy is the high recurrence rate in patients.

Evaluation of Acridine Orange Staining for a Semi-Automated Urinalysis Microscopic Examination at the Point-of-Care.

A urinary tract infection (UTI) can be diagnosed via urinalysis, consisting of a dipstick test and manual microscopic examination. Point-of-care (POC) image-based systems have been designed to automate the microscopic examination for low-volume laboratories or low-resource clinics. In this pilot study, acridine orange (AO) was evaluated as a fluorescence-based contrast agent to aid in detecting and enumerating urine sediment specific for diagnosing a UTI.

Differences in colonic crypt morphology of spontaneous and colitis-associated murine models via second harmonic generation imaging to quantify colon cancer development.

Background: Colorectal cancer remains the second leading cause of cancer death in the United States, and increased risk in patients with ulcerative colitis (a subset of inflammatory bowel disease) has motivated studies into early markers of dysplasia. The development of clinically translatable multiphoton imaging systems has allowed for the potential of in vivo label-free imaging of epithelial crypt structures via autofluorescence and/or second harmonic generation (SHG). SHG has been used to investigate collagen structures in various types of cancer, though the changes that colorectal epithelial collagen structures undergo during tumor development, specifically colitis-associated tumors, have not been fully investigated.

Effects of isoflurane anesthesia on physiological parameters in murine subcutaneous tumor allografts measured via diffuse reflectance spectroscopy.

Diffuse reflectance spectroscopy (DRS) has been used in murine studies to quantify tumor perfusion and therapeutic response. These studies frequently use inhaled isoflurane anesthesia, which depresses the respiration rate and results in the desaturation of arterial oxygen saturation, potentially affecting tissue physiological parameters. However, there have been no controlled studies quantifying the effect of isoflurane anesthesia on DRS-derived physiological parameters of murine tissue.

Sampling depth of a diffuse reflectance spectroscopy probe for in-vivo physiological quantification of murine subcutaneous tumor allografts.

Diffuse reflectance spectroscopy (DRS) is a probe-based spectral biopsy technique used in cancer studies to quantify tissue reduced scattering (μs') and absorption (μa) coefficients and vary in source-detector separation (SDS) to fine-tune sampling depth. In subcutaneous murine tumor allografts or xenografts, a key design requirement is ensuring that the source light interrogates past the skin layer into the tumor without significantly sacrificing signal-to-noise ratio (target of ≥15  dB). To resolve this requirement, a DRS probe was designed with four SDSs (0.

Two-layer inverse model for improved longitudinal preclinical tumor imaging in the spatial frequency domain.

Spatial frequency domain imaging (SFDI) is a widefield, noncontact, and label-free imaging modality that is currently being explored as a new tool for longitudinal tracking of cancer therapies in the preclinical setting. We describe a two-layer look-up-table (LUT) inversion algorithm for SFDI that better accounts for the skin (top layer) and tumor (bottom layer) tissue geometry in subcutaneous tumor models. Monte Carlo (MC) simulations were conducted natively in the spatial frequency domain, avoiding discretization errors associated with Fourier or Hankel transforms of conventional MC simulation results.

Redox-Magnetohydrodynamically Controlled Fluid Flow with Poly(3,4-ethylenedioxythiophene) Coupled to an Epitaxial Light Sheet Confocal Microscope for Image Cytometry Applications.

We present the merging of two technologies to perform continuous high-resolution fluorescence imaging of cellular suspensions in a deep microfluidics chamber with no moving parts. An epitaxial light sheet confocal microscope (e-LSCM) was used to image suspensions enabled by fluid transport via redox-magnetohydrodynamics (R-MHD). The e-LSCM features a linear solid state sensor, oriented perpendicular to the direction of flow, that can bin the emission across different numbers of pixels, yielding electronically adjustable optical sectioning.

Fluorescein as a topical fluorescent contrast agent for quantitative microendoscopic inspection of colorectal epithelium.

Fiber bundle microendoscopic imaging of colorectal tissue has shown promising results, for both qualitative and quantitative analysis. A quantitative image quality control and image feature extraction algorithm was previously designed for quantitative image feature analysis of proflavine-stained colorectal tissue. We investigated fluorescein as an alternative topical stain.

Considerations for point-of-care diagnostics: evaluation of acridine orange staining and postprocessing methods for a three-part leukocyte differential test.

There exists a broad range of techniques that can be used to classify and count white blood cells in a point-of-care (POC) three-part leukocyte differential test. Improvements in lenses, light sources, and cameras for image-based POC systems have renewed interest in acridine orange (AO) as a contrast agent, whereby subpopulations of leukocytes can be differentiated by colorimetric analysis of AO fluorescence emission. We evaluated the effect on test accuracy using different AO staining and postprocessing methods in the context of an image-based POC colorimetric cell classification scheme.

Optical redox ratio identifies metastatic potential-dependent changes in breast cancer cell metabolism.

The development of prognostic indicators of breast cancer metastatic risk could reduce the number of patients receiving chemotherapy for tumors with low metastatic potential. Recent evidence points to a critical role for cell metabolism in driving breast cancer metastasis. Endogenous fluorescence intensity of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) can provide a label-free method for assessing cell metabolism.