Biomedical Spectroscopy and Imaging - Volume 2, issue 2

Authors: Oldenhof, Harriëtte | Akhoondi, Maryam | Sieme, Harald | Wolkers, Willem F.

Article Type: Research Article

Abstract: Cryopreservation of cells requires addition of cryoprotective agents as well as controlled freezing and thawing rates to minimize damage resulting from osmotic dehydration and intracellular ice formation. Typically, there is an optimal cooling rate for maximum survival after freezing and thawing. This cooling rate, however, can vary greatly depending upon intrinsic cellular properties such as membrane composition, osmotic properties, and subzero membrane phase and permeability behavior. In this review, we describe the application of Fourier transform infrared (FTIR) spectroscopy to study membrane phase behavior during freezing of cells. It is shown how membrane phase behavior can be used to derive …the membrane permeability to water at subzero temperatures and the activation energy for water transport. In addition it is shown how subzero membrane hydraulic permeability parameters can be used to simulate the cellular dehydration response at different cooling rates to predict the optimal cooling rate. FTIR studies may thus aid in rationally designing cryopreservation protocols for cells. Show more

Keywords: Cryobiology, cryopreservation, Fourier transform infrared spectroscopy, membrane phase behavior

DOI: 10.3233/BSI-130037

Citation: Biomedical Spectroscopy and Imaging, vol. 2, no. 2, pp. 83-90, 2013

Authors: Macnab, Andrew | Shadgan, Babak | Stothers, Lynn

Article Type: Research Article

Abstract: Transcutaneous near infrared spectroscopy (NIRS) is a recognized means of non-invasively monitoring changes in the concentration of oxygenated and deoxygenated hemoglobin in tissue. However in applications of this technique to the bladder, because the combined thickness of the detrusor muscle and the wall of the organ is only a few millimeters, the question arises whether the trends and variations in hemoglobin concentration detected transcutaneously reflect physiologic changes occurring in the detrusor or are influenced by the effect of overlying tissue on the NIRS signal. In this study a rabbit model was used so that NIRS data could be collected …transcutaneously and then with the optical probe applied directly the anterior bladder wall after surgical exposure of the organ, and the data compared. Studies were done with an Oxymon dual channel spectrometer on 6 anaesthetized New Zealand white rabbits using interoptode distances adjusted for the two measurement sites, a consistent bladder filling and emptying protocol, and exposure to a brief period of controlled hypoxia (oxygen saturation decrease to 80%). Consistent data were obtained from transcutaneous and direct bladder wall measurements which confirms that transcutaneous NIRS monitoring does reflect changes occurring within the detrusor muscle in the anterior bladder wall. Hence, transcutaneous monitoring in humans using appropriate methodology and inter-optode spacing can be expected to avoid any potentially confounding signals from tissues in the abdominal wall overlying the bladder. Show more

Keywords: Bladder wall, detrusor, near infrared spectroscopy, vesical microcirculation, voiding dysfunction

DOI: 10.3233/BSI-130038

Citation: Biomedical Spectroscopy and Imaging, vol. 2, no. 2, pp. 91-99, 2013

Authors: Zhou, Qun | Chen, Jianbo | Sun, Suqin

Article Type: Research Article

Abstract: There is growing popularity in the use of herbal medicines around the world. Due to the presence of a complex mixture of compounds in such medicines, there are few techniques that can be readily used for their characterization. Two-dimensional correlation infrared (2D-IR) spectroscopy is a promising technique that has been applied successfully in the analysis of complex mixtures including herbal medicines. The counterfeit check, growing condition identification, geographic region identification and processing procedure monitoring of herbal medicines using 2D-IR spectroscopy are reviewed.

Keywords: Infrared spectroscopy, two-dimensional correlation spectroscopy, herbal medicines, counterfeit check, geographic origin

DOI: 10.3233/BSI-130039

Citation: Biomedical Spectroscopy and Imaging, vol. 2, no. 2, pp. 101-113, 2013

Authors: Noguchi, Takumi

Article Type: Research Article

Abstract: Photosynthetic water oxidation in plants and cyanobacteria is performed at the Mn4 CaO5 cluster in photosystem II through the light-driven cycle of five intermediates called Si state (i=0–4). This reaction is essential not only as an electron source for CO2 fixation but also as a source of energy and molecular oxygen for life on earth. In this review, the recent progress of the studies using infrared spectroscopy regarding the mechanism of photosynthetic water oxidation was summarized. Flash-induced Fourier-transform infrared (FTIR) difference spectra between the individual S-state transitions (S1 →S2 , S2 →S3 , S3 →S0 and …S0 →S1 ) revealed the structural changes of polypeptide main chains and amino-acid side chains as well as the reactions of water molecules. Proton release processes were also monitored using the infrared bands of buffer molecules, while the miss probabilities of individual transitions were estimated by monitoring an electron flow from the Mn4 CaO5 cluster to an exogenous electron acceptor, ferricyanide, using the CN stretching bands of ferricyanide and ferrocyanide. Furthermore, proton and protein dynamics during the S-state transitions were monitored by dispersive-type time-resolved infrared spectroscopy. These infrared measurements will be powerful methods for full understanding of the mechanism of photosynthetic water oxidation. Show more

Keywords: FTIR, time-resolved infrared spectroscopy, photosynthesis, water oxidation, oxygen evolution, Mn_4CaO_5 cluster, S-state cycle

DOI: 10.3233/BSI-130040

Citation: Biomedical Spectroscopy and Imaging, vol. 2, no. 2, pp. 115-128, 2013

Authors: Bourassa, Megan W. | Leskovjan, Andreana C. | Tappero, Ryan V. | Farquhar, Erik R. | Colton, Carol A. | Van Nostrand, William E. | Miller, Lisa M.

Article Type: Research Article

Abstract: BACKGROUND: In Alzheimer's disease (AD), alterations in metal homeostasis, including the accumulation of metal ions in the plaques and an increase of iron in the cortex, have been well documented but the mechanisms involved are poorly understood. OBJECTIVE: In this study, we compared the metal content in the plaques and the iron speciation in the cortex of three mouse models, two of which show neurodegeneration (5xFAD and Tg-SwDI/NOS2−/− ) (CVN) and one that shows very little neurodegeneration (PSAPP). METHODS: The Fe, Cu and Zn contents and speciation were determined using synchrotron X-ray fluorescence microscopy (XFM) and X-ray absorption …spectroscopy (XAS), respectively. RESULTS: In the mouse models with reported significant neurodegeneration, we found that plaques contained ~25% more copper compared to the PSAPP mice. The iron content in the cortex increased at the late stage of the disease in all mouse models, but iron speciation remains unchanged. CONCLUSIONS: The elevation of copper in the plaques and iron in the cortex is associated with AD severity, suggesting that these redox-active metal ions may be inducing oxidative damage and directly influencing neurodegeneration. Show more

Keywords: Alzheimer's disease, amyloid plaques, copper, iron, transgenic mice, X-ray fluorescence microscopy, X-ray absorption spectroscopy, infrared microscopy

DOI: 10.3233/BSI-130041

Citation: Biomedical Spectroscopy and Imaging, vol. 2, no. 2, pp. 129-139, 2013