Publications by authors named "Howard R Petty"

Although nonrecurrent and recurrent forms of ductal carcinoma in situ (DCIS) of the breast are observed, no evidence-based test can make this distinction. The current retrospective case-control study used archival DCIS samples stained with anti-phospho-Ser226-glucose transporter type 1 and anti-phosphofructokinase type L antibodies. Immunofluorescence micrographs were used to create machine learning models of recurrent and nonrecurrent biomarker patterns, which were evaluated in cross-validation studies.

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A major goal of biomedical research has been the early and quantitative identification of patients who will subsequently experience a cancer recurrence. In this review, I discuss the ability of glycolytic enzyme and transporter patterns within tissues to detect sub-populations of cells within ductal carcinoma in situ (DCIS) lesions that specifically precede cancer recurrences. The test uses conventional formalin fixed paraffin embedded tissue samples.

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Although great effort has been expended to understand cancer's origins, less attention has been given to the primary cause of cancer deaths-cancer recurrences and their sequelae. This interdisciplinary review addresses mechanistic features of aggressive cancer by studying metabolic enzyme patterns within ductal carcinoma in situ (DCIS) of the breast lesions. DCIS lesions from patients who did or did not experience a breast cancer recurrence were compared.

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Although recurrent cancers can become life threatening, little is known about the intracellular events required for cancer recurrences. Due to this lack of mechanistic information, there is no test to predict cancer recurrences or nonrecurrences during early stages of disease. In this retrospective study, we use ductal carcinoma in situ of the breast as a framework to better understand the mechanism of cancer recurrences using patient outcomes as the physiological observable.

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Some patients treated for ductal carcinoma in situ (DCIS) of the breast will experience cancer recurrences, whereas other patients will not. Unfortunately, current techniques cannot identify which preinvasive lesions will lead to recurrent cancer. Because the mechanism of cancer recurrence is unknown, it is difficult to design a test that detects its activity.

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Although many monogenic diseases are understood based upon structural changes of gene products, less progress has been made concerning polygenic disease mechanisms. This article presents a new interdisciplinary approach to understand complex diseases, especially their genetic polymorphisms. I focus upon primary open angle glaucoma (POAG).

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This protocol describes the methods and steps involved in performing biomarker ratio imaging microscopy (BRIM) using formalin fixed paraffin-embedded (FFPE) samples of human breast tissue. The technique is based on the acquisition of two fluorescence images of the same microscopic field using two biomarkers and immunohistochemical tools. The biomarkers are selected such that one biomarker correlates with breast cancer aggressiveness while the second biomarker anti-correlates with aggressiveness.

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Although epidemiological studies propose aggressive and non-aggressive forms of ductal carcinoma in situ (DCIS), they cannot be identified with conventional histopathology. We now report a retrospective study of human biopsy samples using biomarker ratio imaging microscopy (BRIM). Using BRIM, micrographs of biomarkers whose expression correlates with breast cancer aggressiveness are divided by micrographs of biomarkers whose expression negatively correlates with aggressiveness to create computed micrographs reflecting aggressiveness.

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Although metal-metal oxide nanoparticles have attracted considerable interest as catalysts, they have attracted little interest in nanomedicine. This is likely due to the fact that metal oxide semiconductors generally require biologically harmful ultraviolet excitation. In contrast, this study focuses upon WO3/Pt nanoparticles, which can be excited by visible light.

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To provide a means of delivering an artificial immune effector cell-like attack on tumor cells, we report the tumoricidal ability of inorganic WO3/Pt nanoparticles that mimic a leukocyte's functional abilities. These nanoparticles route electrons from organic structures and electron carriers to form hydroxyl radicals within tumor cells. During visible light exposure, WO3/Pt nanoparticles manufacture hydroxyl radicals, degrade organic compounds, use NADPH, trigger lipid peroxidation, promote lysosomal membrane disruption, promote the loss of reduced glutathione, and activate apoptosis.

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To develop new nanoparticle materials possessing anti-oxidative capacity with improved physical characteristics, we have studied titanium-doped cerium oxide (CeTiO) nanoparticles. CeTiO nanoparticles had a mode diameter of 15-20 nm. These nanoparticles demonstrated catalase activity, and did not promote the activation of hemolytic or cytolytic pathways in living cells.

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Background And Objective: Oxidative stress and mitochondrial dysfunction are implicated in the pathogenesis of age-related macular degeneration (AMD). Because increased flavoprotein fluorescence (FPF) is indicative of mitochondrial dysfunction, the authors attempted to detect mitochondrial dysfunction in eyes with AMD using FPF.

Patients And Methods: Six nonexudative eyes with AMD, including three with geographic atrophy (GA), and age-matched control eyes were imaged with a FPF device.

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In this paper we report the enzymatic properties of Ti-doped CeO(2) nanoparticles. The superoxide dismutase activity of Ti-doped nanoparticles is reduced in comparison to undoped nanoceria. In contrast, the oxidase activity of these nanoparticles was unchanged.

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Catalytic nanoparticles represent a potential clinical approach to replace or correct aberrant enzymatic activities in patients. Several diseases, including many blinding eye diseases, are promoted by excessive oxidant stress due to reactive oxygen species (ROS). Cerium oxide and platinum nanoparticles represent two potentially therapeutic nanoparticles that de-toxify ROS.

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A specific colorimetric assay for the determination of glucose-6-phosphate (G6P) was developed. This assay is based on the oxidation of G6P in the presence of glucose-6-phosphate dehydrogenase (G6PD) and nicotinamide adenine dinucleotide phosphate (NADP(+)); the NADPH thereby generated reduces the tetrazolium salt WST-1 [2-(4-indophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium, monosodium salt] to water-soluble yellow-colored formazan with 1-methoxy-5-methylphenazium methylsulfate (1-mPMS) as an electron carrier. The assay is optimized for reaction buffer pH, enzyme/dye concentration, and reaction time course.

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Oxidative stress and mitochondrial dysfunction occur before apoptosis in many retinal diseases. Under these conditions, a larger fraction of flavoproteins become oxidized and, when excited by blue-light, emit green flavoprotein fluorescence (FPF). In this study, we evaluated the utility of FPF as an early indicator of mitochondrial stress, pre-apoptotic cellular instability, and apoptosis of human retinal pigment epithelial (HRPE) cells subjected to hydrogen peroxide (H(2)O(2)) or monocytes (unstimulated or interferon-γ-stimulated) in vitro and of freshly-isolated pieces of human and rat neural retina subjected to H(2)O(2)ex vivo.

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Reactive oxidative compounds including superoxide anions and nitric oxide are believed to play a central role in many blinding eye diseases. In the present study, we examine the effect of ischemia on human retinal pigment epithelial (RPE) cells in an unusual clinical case. We show that ischemia leads to extensive nitrotyrosine deposition in the RPE and choroid, thus indicating NO-dependent oxidative stress.

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Purpose: The inflammatory response in age-related macular degeneration (AMD) is characterized by mononuclear leukocyte infiltration of the outer blood-retina barrier formed by the retinal pigment epithelium (RPE). A key mechanistic element in AMD progression is RPE dysfunction and apoptotic cell loss. The purpose of this study was to evaluate whether monocyte chemoattractant protein (MCP)-1-activated monocytes induce human RPE apoptosis and whether Ca(2+) and reactive oxygen species (ROS) are involved in this process.

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Kinetic studies of nicotinamide adenine dinucleotide phosphate autofluorescence have been conducted in adherent neutrophils using an improved microscopic photometry system incorporating low noise excitation and detection systems. Dynamic autofluorescence oscillations were found with periods ranging from ∼4 min to ∼10 s. The largest portion of the population of oscillating neutrophils (32%) had periods near 2 min.

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Purpose: The retinal pigment epithelium (RPE) is considered a primary site of pathology in age-related macular degeneration (AMD), which is the most prevalent form of irreversible blindness worldwide in the elderly population. Extracellular adenosine triphosphate (ATP) acts as a key signaling molecule in numerous cellular processes, including cell death. The purpose of this study was to determine whether extracellular ATP induces apoptosis in cultured human RPE.

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The human retina is rich in autofluorescent species, such as lipofuscin and melanin. Consequently, it is difficult to localize antigens in the human retina using immunofluorescence microscopy. To address this issue, we have developed a methodology to tag retinal antigens using quantum dot nanoparticles that absorb in the ultraviolet and emit in the infrared, thereby avoiding the visible spectrum.

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Problem: Emerging evidence suggests that metabolism influences immune cell signaling and immunoregulation. To examine the immunoregulatory role of glycolysis in pregnancy, we evaluated the properties of pyruvate kinase in leukocytes from non-pregnant women and those with normal pregnancy and pre-eclampsia.

Method Of Study: We evaluated pyruvate kinase expression in lymphocytes and neutrophils from non-pregnant, pregnant, and pre-eclampsia patients using fluorescence microscopy and flow cytometry.

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Problem: to better understand the immunoregulatory properties of trophoblasts, we have searched for small immunologically active carbohydrates derived from intact trophoblast-like cells.

Method Of Study: using solid phase extraction coupled with HPLC and mass spectrometry methods, we have characterized a low molecular weight carbohydrate-rich fraction associated with JEG-3 cells. We have also tested the bioactivities of selected authentic oligosaccharides found in the oligosaccharide fraction.

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