Oxidative stress appears to act globally and span body systems (e.g., nervous, immune, and endocrine). Currently, there is no single, generally-accepted measurement of oxidative stress. Many possible Show more
Oxidative stress appears to act globally and span body systems (e.g., nervous, immune, and endocrine). Currently, there is no single, generally-accepted measurement of oxidative stress. Many possible measurement approaches focus on the bottom-up analysis of individual molecules (e.g., reactive species, antioxidants, hormones or signaling molecules) or combinations of molecules (e.g., proteomics or metabolomics). Efforts to develop a global measurement of oxidative stress often detect a sample's ability to reduce a metal-ion (e.g., iron or copper) or quench a free radical. Here, we review results from a recently-developed iridium-reducing capacity assay (Ir-RCA) and suggest that this method offers several key benefits as a potential measurement of oxidative stress. First, the Ir-RCA employs simple optical and/or electrochemical measurements that can be extended to high throughput formats. Second, the Ir-RCA appears to be more sensitive than alternative global antioxidant assays. Third, the Ir-RCA measures stable molecular features of a sample. Fourth, the Ir-RCA has been "validated" by showing statistically significant differences in persons diagnosed with schizophrenia (N = 73) versus healthy controls (N = 45). Fifth, the Ir-RCA measurement of oxidative stress is "movable": psychosocial stressors can increase this measure of oxidative stress, while beneficial dietary interventions can decrease this measure of oxidative stress. Limitations and future directions for the Ir-RCA are discussed. Show less
Abstract Imaging contrast agents are widely investigated in preclinical and clinical studies, among which biogenic imaging contrast agents (BICAs) are developing rapidly and playing an increasingly i Show more
Abstract Imaging contrast agents are widely investigated in preclinical and clinical studies, among which biogenic imaging contrast agents (BICAs) are developing rapidly and playing an increasingly important role in biomedical research ranging from subcellular level to individual level. The unique properties of BICAs, including expression by cells as reporters and specific genetic modification, facilitate various in vitro and in vivo studies, such as quantification of gene expression, observation of protein interactions, visualization of cellular proliferation, monitoring of metabolism, and detection of dysfunctions. Furthermore, in human body, BICAs are remarkably helpful for disease diagnosis when the dysregulation of these agents occurs and can be detected through imaging techniques. There are various BICAs matched with a set of imaging techniques, including fluorescent proteins for fluorescence imaging, gas vesicles for ultrasound imaging, and ferritin for magnetic resonance imaging. In addition, bimodal and multimodal imaging can be realized through combining the functions of different BICAs, which helps overcome the limitations of monomodal imaging. In this review, the focus is on the properties, mechanisms, applications, and future directions of BICAs. Show less