HISTORY AND PRESENT STATE OF TRANSLATIONAL ELECTRO-OPTICAL APPLICATIONS TO MEDICINE

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.

QUANTITATIVE REDOX SCANNING OF TISSUE SAMPLES USING A CALIBRATION PROCEDURE

The fluorescence properties of reduced nicotinamide adenine dinucleotide(NADH)and oxidizedflavoproteins(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 metabolicproperties 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 mitochondrialredox state and were determined based on relative signal intensity ratios.Here we report thefurther development of the redox scanning technique by using a calibration method to quantifythe nominal concentration of the fluorophores in tissues.The redox scanner exhibited very goodlinear response in the range of NADH concentration between 165–1318µM and Fp between90–720µM using snap-frozen solution standards.Tissue samples such as human tumor mousexenografts and various mouse organs were redox-scanned together with adjacent NADH and Fpstandards of known concentration at liquid nitrogen temperature.The nominal NADH and Fpconcentrations 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 inmitochondrial redox state in the tissues.

INTRODUCTION SPECIAL ISSUE IN MEMORY OF PROFESSOR BRITTON CHANCE

Britton Chance:One of the Most Outstanding Scientists in the World On June 3rd and 4th,2011,over 300 scientists and professionals from all over the world gathered at the Translational Research Center of the University of Pennsylvania to attend a memorial symposium on\Britton Chance:His Life,Times and Legacy"and a\Molecular Spectroscopy/Imaging Workshop:from bench top to bedside"dedicated to Britton Chance as well.

This research was supported by E.U.FP6 Integrated Project“Molecular Imaging”LSHG-CT-2003-503259 and E.U.FP7 Collaborative Project“FMT-XCT”.R.F.acknowledges support from the Marie Curie Program EST-MolecImag Early Stage Training MEST-CT-2004-007643.

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.

Tightening up the structure, lighting up the pathway:application of molecular constraints and light to manipulate protein folding, self-assembly and function

Chemical cross-linking provides an effective avenue to reduce the conformational entropy of polypeptide chains and hence has become a popular method to induce or force structural formation in peptides and proteins.Recently,other types of molecular constraints,especially photoresponsive linkers and functional groups,have also found increased use in a wide variety of applications.Herein,we provide a concise review of using various forms of molecular strategies to constrain proteins,thereby stabilizing their native states,gaining insight into their folding mechanisms,and/or providing a handle to trigger a conformational process of interest with light.The applications discussed here cover a wide range of topics,ranging from delineating the details of the protein folding energy landscape to controlling protein assembly and function.

左前额叶参与非相关词对的语义编码过程──来自光学成像的佐证

通过研究左前额叶在非相关词对的语义编码过程中的作用，探讨近红外光学成像技术用于脑高级认知活动检测的可行性。被试在两种实验条件下分别学习视觉呈现的20个汉字非相关词对，要求被试或将词对组成一个有意义的句子（深加工），或判断两个词是否具有相同的结构组合（浅加工）。光学成像器即时记录连续光透过额骨及前额皮层后760nm和850nm的漫射光强变化，以此推测相应脑组织的血容量变化。结果表明，与浅加工相比，左下前额叶在深加工时的血容量增多，尤其是背外侧部分。

IMAGING REDOX STATE HETEROGENEITY WITHIN INDIVIDUAL EMBRYONIC STEM CELL COLONIES

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 t NADH)),where NADH is the reduced form of nicotinamide adenine dinucleotide and Fp is the oxidizedflavoproteins,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 embryonicfibroblasts(MEFs)on glass cover slips.The result showed significant heterogeneity in the mitochondrial redox state within individual mESC colonies(size:~200-440μm),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 thefirst 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.

CHOP THER APY INDUCED MITOCHONDRIAL REDOX STATE ALTERATION IN NON-HODGKIN'S LYMPHOMA XENOGRAFTS

We are interested in investigating whether cancer therapy may alter the mitochondrial redox state in cancer cells to inhibit their growth and survival.The redox state can be imaged by the redox scanner that collects the fuorescence signals from both the oxidized-fAavoproteins(Fp)and the reduced form of nicotinamide adenine dinucleotide(NADH)in snap frozen tissues and has been previously employed to study tumor aggressiveness and treatment responses.Here,with the redox scanner we investigated the effects of chemotherapy on mouse xenografts of a human diffuse large B.cell lymphoma cell line(DLCL2).The mice were treated with CHOP therapy,i.e,cyclophosphamide(C)+hydroxydoxorubicin(H)+Oncovin(O)+prednisone(P)with CHO administration on day 1 and prednisone administration on days 1-5.The Fp content of the treated group was significantly decreased(p=0.033)on day 5,and the mitochondrial redox state of the treated group was slightly more reduced than that of the control group(p=0.048).The decrease of the Fp heterogeneity(measured by the mean st andard deviation)had a border-line statistical significance(p=0.071).The result suggests that the mitochondrial metabolism of lymphoma cells was slightly suppressed and the lymphomas became less aggressive after the CHOP therapy.

TWO-SITE PROPERTY OF THENOYLTRIFLUOROACETONE INHIBITING SUCCINATE-UBIQUINONE REDUCTASE

It is proved by using the Dixon plot and the Lineweaver-Burk plot that thenoyltrifluoroacetone (TTFA) has two inhibitive sites affecting the reduction of ubiquinone catalyzed by succinate-ubiquinone reductase. The high affinity site (inhibited at the concentration of thenoyltrifluoroacetone less than 20 μmol/L) shows noncompetitive with substrate Q_2, while the low affinity site (inhibited at the concentration of TTFA over 20 μmol/L) shows competitive. It is suggested that both the reducing steps of Q→QH and QH→QH_2 are inhibited by thenoyltrifluoroacetone.