Cellular protection of morin against the oxidative stress induced by hydrogen peroxide

Flavonoids are a class of secondary metabolites abundantly found in fruits and vegetables. In addition, flavonoids have been reported as potent antioxidants with beneficial effects against oxidative stress-related diseases such as cancer, aging, and diabetes. The present study was carried out to investigate the cytoprotective effects of morin (2',3,4',5,7-pentahydroxyflavone), a member of the flavonoid group, against hydrogen peroxide (H(2)O(2))-induced DNA and lipid damage. Morin was found to prevent the cellular DNA damage induced by H(2)O(2) treatment, which is shown by the inhibition of 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation (a modified form of DNA base), inhibition of comet tail (a form of DNA strand breakage), and decrease of nuclear phospho histone H2A.X expression (a marker for DNA strand breakage). In addition, morin inhibited membrane lipid peroxidation, which is detected by inhibition of thiobarbituric acid reactive substance (TBARS) formation. Morin was found to scavenge the intracellular reactive oxygen species (ROS) generated by H(2)O(2) treatment in cells, which is detected by a spectrofluorometer, flow cytometry, and confocal microscopy after staining of 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA). Morin also induces an increase in the activity of catalase and protein expression. The results of this study suggest that morin protects cells from H(2)O(2)-induced damage by inhibiting ROS generation and by inducing catalase activation.

Induction of heme oxygenase-1 by plant extract KIOM-79 via Akt pathway and NF-E2 related factor 2 in pancreatic beta-cells

The objective of the present study was to determine the mechanism by which KIOM-79 induced heme oxygenase-1 (HO-1) in rat pancreatic beta-cells (RINm5F). A mixture of plant extracts (KIOM-79) was obtained from Magnolia officinalis, Pueraria lobata, Glycyrrhiza uralensis, and Euphorbia pekinensis. HO-1, an antioxidant phase 2 enzyme, was previously reported to possess cytoprotective properties in pancreatic beta-cells. KIOM-79 induced heme oxygenase-1 (HO-1) expression at the mRNA and protein levels, leading to increased HO-1 activity. The transcription factor, NF-E2 related factor 2 (Nrf2), regulates the antioxidant response element (ARE) of the phase 2 detoxifying and antioxidant enzymes, resulting in modulation of HO-1 expression. KIOM-79 increased nuclear translocation, ARE binding, and transcriptional activity of Nrf2. Furthermore, KIOM-79 also elicited activation of Akt (protein kinase B) and LY294004 (inhibitor of Akt)-suppressed KIOM-79-induced activation of Nrf2, which subsequently decreased HO-1 protein levels. Taken together, these data suggest that KIOM-79 augments the cellular antioxidant defense capacity through induction of HO-1 via the Akt-Nrf2-ARE signaling pathway, thereby protecting cells from streptozotocin-induced oxidative stress.

Inhibitory effects of triphlorethol-A on MMP-1 induced by oxidative stress in human keratinocytes via ERK and AP-1 inhibition

Oxidative stress is known to generate reactive oxygen species (ROS) in cells, which subsequently induce the synthesis of matrix metalloproteinases (MMP) and an aging phenomenon. The protective effects of triphlorethol-A, derived from Ecklonia cava, were investigated against hydrogen peroxide (H(2)O(2))-induced damage using human skin keratinocytes. Data showed that triphlorethol-A inhibited ROS formation, induced catalase expression, inhibited DNA damage, and increased cell viability in keratinocytes. Triphlorethol-A treatment significantly reduced MMP-1 expression and production, compared to H(2)O(2)-treated cells. In addition, triphlorethol-A abrogated the activation of extracellular signal regulated protein kinase (ERK), which originates upstream of MMP-1 expression, and was induced by H(2)O(2) treatment. Moreover, triphlorethol-A inhibited DNA binding activity of activator protein-1 (AP-1), a downstream transcription factor of ERK. Data indicate that the antioxidative properties of triphlorethol-A involve the inhibition of MMP-1 via ERK and AP-1 inhibition.

Protective effects of Castanopsis cuspidate through activation of ERK and NF-kappaB on oxidative cell death induced by hydrogen peroxide

The protective effect of Castanopsis cuspidate var. sieboldii was examined on H2O2-induced cell damage. The ethanol extract of Castanopsis cuspidate was found to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and reduce intracellular reactive oxygen species (ROS) generation, and thus prevent lipid peroxidation and cellular DNA damage induced by H2O2. As a result, Castanopsis extract reduced H2O2-induced cell death of V79-4 cells via inhibition of apoptosis. Castanopsis extract was also found to increase catalase activity and its protein expression. Further molecular mechanistic studies revealed that Castanopsis extract enhanced phosphorylation of extracellular signal regulated kinase (ERK) and activity of nuclear factor kappa B (NF-kappaB). Taken together, the results suggest that Castanopsis extract protects V79-4 cells against oxidative damage by enhancing catalase activity and modulating the ERK and NF-kappaB signal pathway.

Rhapontigenin from Rheum undulatum protects against oxidative-stress-induced cell damage through antioxidant activity

The antioxidant properties of rhapontigenin and rhaponticin isolated from Rheum undulatum were investigated. Rhapontigenin was found to scavenge intracellular reactive oxygen species (ROS), the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and hydrogen peroxide (H2O2). The radical scavenging effect of rhapontigenin was more effective than rhaponticin. Rhapontigenin protected against H2O2-induced membrane lipid peroxidation and cellular DNA damage, which are the main targets of oxidative stress-induced cellular damage. The radical scavenging activity of rhapontigenin protected Chinese hamster lung fibroblast (V79-4) cells exposed to H2O2 by inhibiting apoptosis. Rhapontigenin inhibited cell damage induced by serum starvation and was also found to increase the activity of catalase and its protein expression. Further, rhapontigenin increased phosphorylation of extracellular signal-regulated kinase (ERK) and inhibited the activity of activator protein 1 (AP-1), a redox-sensitive transcription factor. In summary, these results suggest that rhapontigenin protects V79-4 cells against oxidative damage by enhancing the cellular antioxidant activity and modulating cellular signal pathways.

Triphlorethol-A induces heme oxygenase-1 via activation of ERK and NF-E2 related factor 2 transcription factor

Triphlorethol-A, phlorotannin found in Ecklonia cava, induced heme oxygenase-1 (HO-1) expression at mRNA and protein levels, leading to increased HO-1 activity. Transcription factor NF-E2 related factor 2 (Nrf2) regulates antioxidant response element (ARE) of phase 2 detoxifying and antioxidant enzymes. Triphlorethol-A increased nuclear translocation, ARE binding, and transcriptional activity of Nrf2. Triphlorethol-A exhibited activation of ERK and U0126, inhibitor of ERK kinase, suppressed triphlorethol-A induced activation of Nrf2, finally decreased HO-1 protein level. Taken together, these data suggest that triphlorethol-A augments cellular antioxidant defense capacity through induction of HO-1 via ERK-Nrf2-ARE signaling pathway, thereby protecting cells from oxidative stress.

Cytoprotective Effects of KIOM-79 on Streptozotocin Induced Cell Damage by Inhibiting ERK and AP-1

The present study investigated the potential cytoprotective properties of a combination of plant extracts (KIOM-79) obtained from Magnolia officinalis, Pueraria lobata, Glycyrrhiza uralensis, and Euphorbia pekinensis, against the oxidative stresses induced by streptozotocin (STZ) in a rat pancreatic beta-cells (RINm5F). KIOM-79 was found to scavenge intracellular reactive oxygen species (ROS), thereby preventing DNA damage and lipid peroxidation. The KIOM-79 inhibited apoptosis of the beta-cells exposed to STZ via radical scavenging activity and activation of antioxidant enzymes. KIOM-79 inhibited activation of extracellular regulated kinase (ERK) induced by STZ and inhibited DNA binding activity of an activator protein-1 (AP-1), a downstream transcription factor of ERK. Taken together, these findings suggest that KIOM-79 protects against STZ induced cell death in RINm5F cells by inhibiting ROS generation and the ERK pathway.

Caffeic acid protects hydrogen peroxide induced cell damage in WI-38 human lung fibroblast cells

Cytoprotective effect of caffeic acid (3,4-dihydroxy cinnamic acid) on human lung fibroblast (WI-38) cells against hydrogen peroxide induced damage was investigated. Caffeic acid was found to scavenge intracellular reactive oxygen species, and 1,1-diphenyl-2-picrylhydrazyl radical, and thus prevented lipid peroxidation. The caffeic acid protected cell damage of WI-38 cells exposed to hydrogen peroxide (H(2)O(2)), via the activation of extracellular signal regulated kinase protein. Caffeic acid increased the activity of catalase and its protein expression. Hence, from the present study, it is suggestive that caffeic acid protects WI-38 cells against H2O2 damage by enhancing the cellular antioxidant activity.

Protective effect of triphlorethol-A from Ecklonia cava against ionizing radiation in vitro

We studied the cytoprotective effect of triphlorethol-A against gamma-ray radiation-induced oxidative stress. In this study, hydrogen peroxide, which is a reactive oxygen species (ROS), was detected using 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA) assay. Triphlorethol-A reduced intracellular hydrogen peroxide generated by gamma-ray radiation. This compound provided protection against radiation-induced membrane lipid peroxidation and cellular DNA damage which are the main targets of radiation-induced damage. Triphlorethol-A protected the cell viability damaged by the radiation through inhibition of apoptosis. Triphlorethol-A reduced the expression of bax and activated caspase 3 induced by radiation, but recovered the expression of bcl-2 decreased by radiation. Taken together, the results suggest that triphlorethol-A protects cells against oxidative damage induced by radiation through reducing ROS.

Cytoprotective effect of phloroglucinol on oxidative stress induced cell damage via catalase activation

We investigated the cytoprotective effect of phloroglucinol, which was isolated from Ecklonia cava (brown alga), against oxidative stress induced cell damage in Chinese hamster lung fibroblast (V79-4) cells. Phloroglucinol was found to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydrogen peroxide (H(2)O(2)), hydroxy radical, intracellular reactive oxygen species (ROS), and thus prevented lipid peroxidation. As a result, phloroglucinol reduced H(2)O(2) induced apoptotic cells formation in V79-4 cells. In addition, phloroglucinol inhibited cell damage induced by serum starvation and radiation through scavenging ROS. Phloroglucinol increased the catalase activity and its protein expression. In addition, catalase inhibitor abolished the protective effect of phloroglucinol from H(2)O(2) induced cell damage. Furthermore, phloroglucinol increased phosphorylation of extracellular signal regulated kinase (ERK). Taken together, the results suggest that phloroglucinol protects V79-4 cells against oxidative damage by enhancing the cellular catalase activity and modulating ERK signal pathway.

Trichotomoside: A New Antioxidative Phenylpropanoid Glycoside fromClerodendron trichotomum

The structure and antioxidant properties of a new natural glycoside, trichotomoside (1), isolated from Clerodendron trichotomum, were investigated. Trichotomoside was identified as 2-(3-hydroxy-4-methoxyphenyl)ethyl 3-O-(2,3-di-O-acetyl-alpha-L-rhamnopyranosyl)-4-O-[(2E)-3-(3-hydroxy-4-methoxyphenyl)prop-2-enoyl]-beta-D-glucopyranoside. The compound was active towards intracellular reactive oxygen species (ROS) and exhibited DPPH-radical-scavenging effects. The radical-scavenging activity of 1 was found to protect the viability of Chinese hamster lung fibroblasts (V79-4 cells) exposed to H2O2 and gamma-irradiation.

Cytotoxic effect of 7beta-hydroxycholesterol on human NCI-H460 lung cancer cells

The cytotoxic activity of 7beta-hydroxycholesterol (7beta-OHC) was evaluated on human NCI-H460 lung cancer cells. 7beta-OHC decreased clonogenic survival of NCI-H460 in a dose dependent pattern. 7beta-OHC induced apoptosis in NCI-H460, with the characteristic features like increase in sub-G(1) hypodiploid (apoptotic) cells, and apoptotic body formation, as evidenced by flow cytometry and fluorescence microscope, respectively. Apoptosis was also associated with loss of mitochondrial transmembrane potential, and the activation of caspases 9 and 3. 7beta-OHC resulted in generation of reactive oxygen species (ROS) during apoptosis. On the whole, the results indicated that 7beta-OHC inhibited the proliferation of NCI-H460 cells through apoptosis via caspase activation.

Eckol isolated from Ecklonia cava attenuates oxidative stress induced cell damage in lung fibroblast cells

We have investigated the cytoprotective effect of eckol, which was isolated from Ecklonia cava, against oxidative stress induced cell damage in Chinese hamster lung fibroblast (V79-4) cells. Eckol was found to scavenge 1,1-diphenyl-2-picrylhydrazyl radical, hydrogen peroxide (H(2)O(2)), hydroxy radical, intracellular reactive oxygen species (ROS), and thus prevented lipid peroxidation. As a result, eckol reduced H(2)O(2) induced cell death in V79-4 cells. In addition, eckol inhibited cell damage induced by serum starvation and radiation by scavenging ROS. Eckol was found to increase the activity of catalase and its protein expression. Further, molecular mechanistic study revealed that eckol increased phosphorylation of extracellular signal-regulated kinase and activity of nuclear factor kappa B. Taken together, the results suggest that eckol protects V79-4 cells against oxidative damage by enhancing the cellular antioxidant activity and modulating cellular signal pathway.

Cytoprotective effect of tectorigenin, a metabolite formed by transformation of tectoridin by intestinal microflora, on oxidative stress induced by hydrogen peroxide

In the present study, the antioxidative properties of tectorigenin, a metabolite formed by transformation of tectoridin by intestinal microflora, were investigated. Tectorigenin was found to scavenge intracellular reactive oxygen species, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and thus prevented lipid peroxidation. The radical scavenging activity of tectorigenin protected the viability of Chinese hamster lung fibroblast (V79-4) cells exposed to hydrogen peroxide (H2O2) via activation of extracellular signal regulated kinase (ERK) pathway. Furthermore, tectorigenin reduced the apoptotic cells formation and cell cycle arrest at G2/M phase induced by H2O2. Tectorigenin increased the activities of cellular antioxidant enzymes like superoxide dismutase, catalase, glutathione peroxidase, and also increased their protein level. Taken together, these findings suggest that tectorigenin protected V79-4 cells against H2O2 damage, by enhancing the antioxidative activity and by activating ERK pathway.

Antioxidant activity of ethanol extract of Callophyllis japonica

The antioxidant properties of the red seaweed Callophyllis japonica were investigated. An ethanol extract isolated from C. japonica exhibited intracellular reactive oxygen species, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and lipid peroxidation inhibitory activity. The radical scavenging activity of the extract protected the viability of Chinese hamster lung fibroblast (V79-4) cells exposed to H2O2. Furthermore, the extract reduced the proportion of apoptotic cells induced by H2O2, as demonstrated by decreased sub-G1 hypo-diploid cells and decreased apoptotic body formation. The extract also increased the activities of the cellular antioxidant enzymes, superoxide dismutase and catalase. Together, these findings suggest that C. japonica exhibits antioxidant properties.

Protective effect of puerariae radix on oxidative stress induced by hydrogen peroxide and streptozotocin

This study evaluated the protective effect of Puerariae radix against the oxidative stress induced by hydrogen peroxide (H2O2) and streptozotocin in vitro and in vivo, respectively. The ethanol extract scavenged intracellular reactive oxygen species (ROS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and prevented lipid peroxidation. This radical scavenging activity of the ethanol extract protected the cell viability of Chinese hamster lung fibroblast (V79-4) cells exposed to H2O2. Furthermore, this extract reduced the formation of apoptotic cells induced by H2O2, which was demonstrated by the decreased number of sub G(1) hypo-diploid cells and apoptotic cell body formation. The extract increased the activities of the cellular antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT). Administration of the extract to the streptozotocin induced diabetic rats decreased the blood glucose levels. The diabetic rats showed low activities of superoxide dismutase and catalase in the liver, and the ethanol extract increased the CAT activity. The increased level of lipid peroxidation in the diabetic rats reverted to near normal levels after being treated with the extract. This study showed that Puerariae radix was effective in the amelioration of diabetes, which may be a consequence of its antioxidant potential.

G1 phase arrest of the cell cycle by a ginseng metabolite, compound K, in U937 human monocytic leukamia cells

We recently reported that the ginseng saponin metabolite, compound K (20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol, IH901), inhibits the growth of U937 cells through caspase-dependent apoptosis pathway. In this study, we further characterized the effects of compound K on U937 cells and found that, in addition to apoptosis, compound K induced the arrest of the G1 phase. The compound K treated U937 cells showed increased p21 expression; an inhibitory protein of cyclin-cdk complex. The up-regulation of p21 was followed by the inactivation of cyclin D and the cdk4 protein, which act at the early G1 phase, and cyclin E, which acts at the late G1 phase. Furthermore, compound K induced the activation of JNK and the transcription factor AP-1, which is a downstream target of JNK. These findings suggest that the up-regulation of p21 and activation of JNK in the compound K treated cells contribute to the arrest of the G1 phase.

Triphlorethol-A from Ecklonia cava protects V79-4 lung fibroblast against hydrogen peroxide induced cell damage

In the present study, triphlorethol-A, a phlorotannin, was isolated from Ecklonia cava and its antioxidant properties were investigated. Triphlorethol-A was found to scavenge intracellular reactive oxygen species (ROS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and thus prevented lipid peroxidation. The radical scavenging activity of triphlorethol-A protected the Chinese hamster lung fibroblast (V79-4) cells exposed to hydrogen peroxide (H2O2) against cell death, via the activation of ERK protein. Furthermore, triphlorethol-A reduced the apoptotic cells formation induced by H2O2. Triphlorethol-A increased the activities of cellular antioxidant enzymes like, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Hence, from the present study, it is suggestive that triphlorethol-A protects V79-4 cells against H2O2 damage by enhancing the cellular antioxidative activity.

Antioxidant activity of isoacteoside from Clerodendron trichotomum

The antioxidant properties of isoacteoside, isolated from Clerodendron trichotomum (Verbenaceae), were investigated. This compound scavenged intracellular reactive oxygen species (ROS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and prevented lipid peroxidation. This radical scavenging activity of isoacteoside protected cell viability of Chinese hamster lung fibroblast (V79-4) cells exposed to hydrogen peroxide (H2O2). Furthermore, isoacteoside reduced the apoptotic cells formation induced by H2O2, as demonstrated by the decreased number of sub-G1 hypo-diploid cells and apoptotic cell body formation. However, isoacteoside increased the activities of cellular antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT). Taken together, these findings suggest that isoacteoside, isolated from C. trichotomum, possesses antioxidant properties.

Antioxidant Activity of Jionoside D from Clerodendron trichotomum

The antioxidant property of jionoside D, isolated from Clerodendron trichotomum (Verbenaceae), was investigated. This compound showed scavenging activity of intracellular reactive oxygen species and of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, as well as lipid peroxidation inhibitory activity. This radical scavenging activity of jionoside D protected the cell viability of Chinese hamster lung fibroblast (V79-4) cells exposed H2O2. Furthermore, jionoside D reduced the apoptotic cells induced by H2O2, as demonstrated by the decreased number of sub G1 hypo-diploid cells and apoptotic body formation. However, it increased the activities of cellular antioxidant enzymes, superoxide dismutase and catalase. Taken together, these findings suggest that jionoside D, isolated from C. trichotomum, exhibits antioxidant properties.

A feasibility study of multispectral image analysis of skin tumors

To develop a noninvasive, early-detection method for skin cancers, a feasibility study of multispectral image analysis was investigated. The three most frequently occurring skin cancer types, ten basal-cell carcinomas (BCCs), ten squamous-cell carcinomas (SCCs) and five malignant melanomas (MMs) were studied, along with ten normal moles. Images were acquired by a charge-coupled device camera using eight narrow-band filters ranging from 450 nm to 800 nm, at 50-nm intervals. To extract main features of these tumors, principal components analysis (PCA) was performed, because it projects the multidimensional (here, eight-dimensional) data in the direction of maximum data variance. Then, the primary PCA components for red, green, and blue subset images were analyzed in terms of hue-saturation-intensity (HSI). By hue distributions, the BCCs and SCCs were differentiated from the MMs and normal moles. Texture information was used to further classify tumor types after the HSI analysis. The texture analysis, performed using a spatial gray-level co-occurrence matrix (SGCM), could separate MMs from normal moles. The BCCs and SCCs were further studied by Fisher's linear discriminant analysis. Distribution was described as a Gaussian mixture model. By this classification procedure, seven BCCs, eight SCCs, five MMs, and ten NMs were correctly classified. Three BCCs and two SCCs were unseparable. Thus, multispectral skin cancer image analysis has potential to diagnose skin cancers.

Preliminary study of real-time fiber optic based protein C biosensor

Deficiency of protein C (PC), one of the human body's key anticoagulants, can lead to massive thrombotic complications. There is a diagnostic need to perform real-time assays, in order to quickly identify and treat this disease. An immuno-optical biosensor for the diagnosing of PC deficiencies and monitoring of PC concentrations is being developed for this purpose. Monoclonal antibody against PC (anti-PC) is immobilized on the surface of a tapered quartz fiber that is enclosed in a glass tube (capacity approximately 200 microL). Following sample injection, PC within a sample binds to the anti-PC in a highly specific reaction. The system is then probed with a fluorophore-tagged secondary antibody against PC. Excitation light is applied through the fiber, and the fluorescence intensity is correlated with the PC concentration in the sample. This study presents (1) a feasibility, direct binding assay, (2) a comparison of methods to immobilize anti-PC upon the fiber (direct immobilization vs an avidin-biotin bridge), and (3) effectiveness of an elution step to regenerate the fiber. PC-deficient patients typically have a concentration range less than 2.5 microg/mL. It was found that the sensor could detect PC levels down to 0.1 microg/mL in pure buffer with minimal optimization. Avidin-biotin immobilization of the primary antibody produced enhanced signals, up to 470% of the original intensities. Preliminary fiber regeneration tests achieved nearly a 50% increase in fiber lifetime with the use of a CaCl(2) elution step. Ultimately, further development may lead to automation and the use of the system as a multi-blood factor analyzer.

Isolation of a novel microorganism, pestalotia heterocornis, producing paclitaxel

Pestalotia heterocornis was isolated from soil collected in yew forest and was shown to produce paclitaxel in semisynthetic liquid media. The presence of paclitaxel in the fungal extract was confirmed by FAB mass spectrometry and NMR spectroscopy. The maximum yield of paclitaxel was 31 &mgr;g per liter. Optimal paclitaxel production occurred after 5-7 days in a 20-liter scale fermentation at 23 degrees C. These results indicate that P. heterocornis is an excellent candidate for consideration in fermentation technology. Copyright 1999 John Wiley & Sons, Inc.

Preliminary study of biosensor optimization for the detection of protein C

Methods to develop an immuno-optical biosensor for the detection and monitoring of Protein C (PC) concentrations are described. A tapered quartz fiber is enclosed in a glass tube (capacity approximately 300 microliters) and monoclonal antibody against PC (anti-PC) is immobilized on the surface of this fiber. PC within a sample, when injected into the chamber, will bind to the anti-PC in a specific reaction. The system is then probed with a fluorophore tagged secondary antibody against PC, also binding to PC in a specific reaction. Excitation light is applied through the fiber, and the amount of fluorescence is correlated with the PC concentration in the sample. This study offers encouraging results for the detection of PC deficiency in real-time.

Localization of a fluorescent object in highly scattering media via frequency response analysis of near infrared-time resolved spectroscopy spectra

Frequency response analysis via pulse testing for engineering systems and near infrared (NIR) time resolved spectroscopy (TRS) for biological system characterization involve identical principles: the system of interest is disturbed by an input pulse and the output response is observed. Since a sharp pulse, such as the Dirac delta function, contains the information of multimodulation frequencies (theoretically from 0 to infinity in frequency) a narrow pulse TRS input can produce a wide range frequency response for identifying any system of interest. Currently used NIR-TRS spectral analyses either fit the spectra with a known theoretical solution or use photon mean time-of-flight. Transforming the system time domain representation to the frequency domain generates five system parameters that can be valuable for process identification utility: steady state gain, time constant, system order, and magnitude ratio and phase shift over a wide frequency range. Optical contrast agents or fluorescent agents can be used to enhance the capability of optical instruments in detecting biological heterogeneities. In this article, magnitude ratio, phase shift, and other system parameters derived from the transfer function of systems with both a fluorescent absorber and a regular absorber are correlated with the position of the absorber. This technique is important in that ultimately it can be used to enhance optical medical imaging.

Application of near-IR time-resolved spectroscopy and frequency response analysis for deep vein thrombosis detection

Frequency response analysis is applied to analyze NIR-TRS spectra in a tissue model with a simulated thrombus. The value changes in parameters obtained from frequency response analysis are correlated with heterogeneity position in three dimensions. The goal of this research is to noninvasively localize deep vein thrombosis in the human leg through the use of this novel combination.

Feasibility study of a single- and multiple-source near-infrared phase-modulation device for characterizing biologic systems

Near-infrared (NIR) spectroscopy is an inexpensive and noninvasive optical method to characterize biologic and physiologic systems. Measurements of oxygen saturation in various organs, cytochrome oxidase concentration, and glucose concentration in tissue are examples of NIR spectroscopy applications. This instrument also has potential for diagnostic imaging by comparing the optical properties of a given point in tissue with those of the surrounding areas, e.g., tumor localization, hematoma detection, or deep vein thrombosis detection. Currently, NIR spectroscopy is available in three modalities: time-resolved spectroscopy (TRS), continuous-wave spectroscopy (CWS), and a phase-modulation device. This paper describes a single-source phase-modulation device and a multiple-source (in- and anti-phased) device and their application to system identification. The phase and intensity information for homogeneous systems is correlated with system and instrumental parameters. Phase and intensity changes resulting from the presence of one and two absorbers are illustrated. The sensitivity of in- and anti-phased phase-modulation devices (phased arrays) is demonstrated. The use of amplitude-modulated phased array for heterogeneity detection is described.

Chromatographic process identification for protein C purification using frequency response analysis

Frequency response analysis is applied for the analysis of liquid chromatography output of protein separation. Reduced data from simple chromatograms suggest that various Bode plot parameters, magnitude ratios, phase shift, the steady state gain, break frequency, and system order in the frequency domain, can be used to gain phenomenological insights on the system. Such an approach is advantageous because the validity of the model can be checked for two plots, the magnitude ratio vs. frequency and the phase shift vs. frequency, as compared to a single plot in the time domain. This approach also provides a useful empirical-tool which can be quantifiably used for process validation and scale-up, especially for immunoaffinity and immobilized metal affinity chromatographic systems used for protein C purification.

Reusable, real-time, immuno-optical protein C biosensor

A Protein C (PC) biosensor can be used to diagnose PC deficiency, to monitor the PC level in the blood of PC deficient patients, and to measure the PC concentration in other PC-containing samples, such as PC producing animal cell culture broth or transgenic animal milk. A fully functional biosensor requires extremely high sensitivity and specificity, and real-time measurement. To satisfy these requirements, it is proposed to develop an immuno-optical fiber biosensor that utilizes PC-specific biomolecules (PC probes) tagged with fluorophores. The method involves immobilizing monoclonal antibody against PC (anti-PC) on the surface of an optical fiber. When PC in a sample is adsorbed to the anti-PC on the fiber, it can be reached with the fluorophore tagged PC-probe. The intensity of light transported through the optical fiber, therefore, can be correlated with the concentration of PC in the sample. The sensor will be designed so it can be reused, following a simple elution step, thus reducing diagnostic expense. The preliminary study shows encouraging future for the real-time optical PC biosensor.

Separation of recombinant human protein C from transgenic animal milk using immobilized metal affinity chromatography

Protein C is an important serine protease due to its ability to proteolytically cleave activated Factors V and VIII. Excess coagulation and blood agglutination can lead to plugged capillaries, thereby reducing oxygen transport to interstitial tissues. To treat patients with hereditary and acquired protein C deficiency would require a greater amount of Protein C than that available from human plasma. However, the potential demand for this protein could be met by the production of human protein C from transgenic animal mammary glands. Thus, research into inexpensive, efficient methods to purify proteins from transgenic animal milk will be a critical area of study for the large scale production of protein C. Immobilized metal affinity chromatography (IMAC) is a novel method for the purification of protein C. A proposed method of purification is to take advantage of protein C's strong metal ion binding characteristics with IMAC to assist in the separation from transgenic animal milk. The separation procedure is benchmarked against current systems in use by the American Red Cross for purification of Protein C from transgenic porcine milk. Common problems in developing separation schemes for new therapeutics are the initial availability of the product (protein), and time-to-market concerns. Extensive experimental tests for scaleable purification schemes are often cost and time prohibitive. In order to optimize an IMAC protocol with minimal waste of time and resources, total quality management tools have been adopted. Initial experiments were designed to choose buffer conditions, eluents, immobilized valence metals, and flow rates using Taguchi experimental design, which is a total quality management (TQM) tool. One of the values of Taguchi methods lies in the use of Latin orthogonal sets. Through the use of the orthogonal sets, the total number of experiments may be reduced, shortening the focus time on optimal conditions.

Highly scattering optical system identification via frequency response analysis of NIR-TRS spectra

Frequency response analysis via pulse testing is often used for the characterization of engineering systems. Near infrared-time resolved spectroscopy (NIR-TRS) is a frequently used technique for the analysis of biological system properties. Since the TRS input is a very sharp photon pulse, a well designed TRS input pulse can produce a multi-frequency response over the useful frequency range for the system identification. This new approach for analyzing NIR-TRS provides new optical system parameters (e.g., magnitude ratio and phase shift at multi-frequencies, system time constant, system order, and steady state gain) that are not available by traditional TRS spectra analysis. In this paper, the basic theory of pulse reduction is introduced for the multi-modulation frequency response of TRS spectra. Homogeneous system response with various absorption and scattering properties were analyzed for the multi-system parameters. In heterogeneous systems, the position of the localized absorber is correlated with the multi-parameters, which can ultimately be used to enhance medical imaging.