Britton Chance was a pioneer in many scientific fields such as enzymatic reaction kinetics, bioenergetics, metabolism, in vivo NMR, and biophotonics. As an engineer, physical chemist, physicist, physiologist, biophysicist, biochemist, innovator and educator, he had worked in diversified fields over extended periods between 1926 until his death in 2010, at the age of 97. In order to illustrate his scientific career and great impact on research from a new perspective, we employ scientometric analysis tools to analyze the publications of Britton Chance with data downloaded from the ISI Citation Indexes in April 2013. We included articles, reviews and proceeding papers but excluded meeting abstracts. In total, we obtained 1023 publication records with 1236 authors in 266 journals with 17,114 citations from 1945 to 2013. We show the annual publications and citations that Britton Chance received from 1945 to 2013, and generate HistCite maps on the basis of the global citations (GCS) and local (self) citations (LCS) to show the citation relationships among the top-30 publications of Britton Chance. Metabolism and the development of physical methods to probe it appear to be the connecting thread of the lifelong research of Britton Chance. Furthermore, we generate the journal map and co-authorship map to show the broad scope of research topics and collaborators and the high impacts of the scientific oeuvre of Britton Chance ranging from physics, engineering, chemistry and biology to medicine.

Redox state mediates embryonic stem cell (ESC) differentiation and thus offers an important complementary approach to understanding the pluripotency of stem cells. NADH redox ratio (NADH/(Fp+ NADH)), where NADH is the reduced form of nicotinamide adenine dinucleotide and Fp is the oxidized flavoproteins, has been established as a sensitive indicator of mitochondrial redox state. In this paper, we report our redox imaging data on the mitochondrial redox state of mouse ESC (mESC) colonies and the implications thereof. The low-temperature NADH/Fp redox scanner was employed to image mESC colonies grown on a feeder layer of gamma-irradiated mouse embryonic fibroblasts (MEFs) on glass cover slips. The result showed significant heterogeneity in the mitochondrial redox state within individual mESC colonies (size: ~200-440 μm), exhibiting a core with a more reduced state than the periphery. This more reduced state positively correlates with the expression pattern of Oct4, a well-established marker of pluripotency. Our observation is the first to show the heterogeneity in the mitochondrial redox state within a mESC colony, suggesting that mitochondrial redox state should be further investigated as a potential new biomarker for the stemness of embryonic stem cells.

The source of energy for life is the tissue mitochondria and they demand a complex chain of biochemicals to ensure proper physiological function. Classically, the blood levels, and not the tissue levels of these metabolites, are determined by expensive and time-consuming biochemical analyses. Since the tissue mitochondria are the consumers of the substrates of glycolysis and of fatty acid metabolism, their redox state is a unique accessible monitor of tissue metabolism and its blockade due to toxins.

We have imaged mitochondrial oxidation–reduction states by taking a ratio of mitochondrial fluorophores: NADH (reduced nicotinamide adenine dinucleotide) to Fp (oxidized flavoprotein). Although NADH has been investigated for tissue metabolic state in cancer and in oxygen deprived tissues, it alone is not an adequate measure of mitochondrial metabolic state since the NADH signal is altered by dependence on the number of mitochondria and by blood absorption. The redox ratio, NADH/(Fp+NADH), gives a more accurate measure of steady-state tissue metabolism since it is less dependent on mitochondrial number and it compensates effectively for hemodynamic changes. This ratio provides important diagnostic information in living tissues. In this study, the emitted fluorescence of mouse colon in situ is passed through an emission filter wheel and imaged on a CCD camera. Redox ratio images of the healthy and hypoxic mouse intestines clearly showed significant differences. Furthermore, the corrected redox ratio indicated an increase from an average value of 0.51 ± 0.10 in the healthy state to 0.92 ± 0.03 in dead tissue due to severe ischemia (N = 5). We show that the CCD imaging system is capable of displaying the metabolic differences in normal and ischemic tissues as well as quantifying the redox ratio in vivo as a marker of these changes.

Mitochondrial redox states provide important information about energy-linked biological processes and signaling events in tissues for various disease phenotypes including cancer. The redox scanning method developed at the Chance laboratory about 30 years ago has allowed 3D highresolution (～ 50 × 50 × 10μm³) imaging of mitochondrial redox state in tissue on the basis of the fluorescence of NADH (reduced nicotinamide adenine dinucleotide) and Fp (oxidized flavoproteins including flavin adenine dinucleotide, i.e., FAD). In this review, we illustrate its basic principles, recent technical developments, and biomedical applications to cancer diagnostic and therapeutic studies in small animal models. Recently developed calibration procedures for the redox imaging using reference standards allow quantification of nominal NADH and Fp concentrations, and the concentration-based redox ratios, e.g., Fp/(Fp+NADH) and NADH/(Fp+NADH) in tissues. This calibration facilitates the comparison of redox imaging results acquired for different metabolic states at different times and/or with different instrumental settings. A redox imager using a CCD detector has been developed to acquire 3D images faster and with a higher in-plane resolution down to 10 μm. Ex vivo imaging and in vivo imaging of tissue mitochondrial redox status have been demonstrated with the CCD imager. Applications of tissue redox imaging in small animal cancer models include metabolic imaging of glioma and myc-induced mouse mammary tumors, predicting the metastatic potentials of human melanoma and breast cancer mouse xenografts, differentiating precancerous and normal tissues, and monitoring the tumor treatment response to photodynamic therapy. Possible future directions for the development of redox imaging are also discussed.

The fluorescence properties of reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins (Fp) including flavin adenine dinucleotide (FAD) in the respiratory chain are sensitive indicators of intracellular metabolic states and have been applied to the studies of mitochondrial function with energy-linked processes. The redox scanner, a three-dimensional (3D) low temperature imager previously developed by Chance et al., measures the in vivo metabolic properties of tissue samples by acquiring fluorescence images of NADH and Fp. The redox ratios, i.e. Fp/(Fp+NADH) and NADH/(Fp+NADH), provided a sensitive index of the mitochondrial redox state and were determined based on relative signal intensity ratios. Here we report the further development of the redox scanning technique by using a calibration method to quantify the nominal concentration of the fluorophores in tissues. The redox scanner exhibited very good linear response in the range of NADH concentration between 165–1318μM and Fp between 90–720μM using snap-frozen solution standards. Tissue samples such as human tumor mouse xenografts and various mouse organs were redox-scanned together with adjacent NADH and Fp standards of known concentration at liquid nitrogen temperature. The nominal NADH and Fp concentrations as well as the redox ratios in the tissue samples were quantified by normalizing the tissue NADH and Fp fluorescence signal to that of the snap-frozen solution standards. This calibration procedure allows comparing redox images obtained at different time, independent of instrument settings. The quantitative multi-slice redox images revealed heterogeneity in mitochondrial redox state in the tissues.

We utilized Near-Infrared (NIR) spectroscopy to closely investigate the activation change in anterior prefrontal cortex (aPFC) during verbal anagram problem-solving and learning. We used a parametric design of anagram-solving with three difficulty levels and evaluated anagram skill with two sets of subjects and protocols. The first protocol was a one-time evaluation of untrained subjects (n = 10) and the second protocol evaluated subjects over 6 weeks of training (n = 6). The untrained subjects in the first protocol demonstrated blood oxygenation corresponding to neuronal activation in the aPFC in response to medium and hard difficulty levels of the stimuli, while the easy anagram task deoxygenated the aPFC bilaterally, corresponding to deactivation. Higher performers have more aPFC activation than lower performers in the medium difficulty level anagram-solving task. Six weeks of training in the second protocol showed that training reduced oxygenation in aPFC. In particular, subjects with lower baseline skill in anagram production showed a larger reduction in oxygenation where true performance gains occurred (medium difficulty) and smaller reduction where the performance gains were limited (hard anagrams). Association of the aPFC activation with the difficulty of the complex task suggests that aPFC is a part of a circuit for execution of task performance. In addition, more use of aPFC by untrained high performers suggests that the role of the aPFC is to increase efficiency of a problem-solving task. Thus, the NIR spectroscopy showed that the aPFC is a key structure in the circuit implementing the development of anagram skill.

This paper reviews the history of the optoelectric devices applied to biomedical sciences in 20th century. It describes history of Vacuum tubes and Spectroscopies with the author’s personal experiences, especially doublebeam spectroscopy. Further, the present developments of Near Infra Red (NIR) devices are described in translational biomedical applications. It includes particulary micro optoelectronics developments and present status of NIR breast cancer detection. Lastly, intrinsic molecular biomarkers are discussed especially NIR measurements of angiogenensis, hypermetabolism and heat production for cancer detection.