The Experts below are selected from a list of 104922 Experts worldwide ranked by ideXlab platform
Yan-zhong Chang - One of the best experts on this subject based on the ideXlab platform.
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Nasal delivery of nanoliposome-encapsulated ferric ammonium citrate can increase the Iron Content of rat brain.
Journal of nanobiotechnology, 2017Co-Authors: Xueling Guo, Hong Zheng, Yuetong Guo, Yan Wang, Gregory J. Anderson, Lina Geng, Yan-zhong ChangAbstract:Iron deficiency in children can have significant neurological consequences, and Iron supplementation is an effective treatment of choice. However, traditional routes of Iron supplementation do not allow efficient Iron delivery to the brain due to the presence of the blood–brain barrier. So an easily delivered Iron formulation with high absorption efficiency potentially could find widespread application in Iron deficient infants. In this study, we have developed and characterized a nanovesicular formulation of ferric ammonium citrate (ferric ammonium citrate nanoliposomes, FAC-LIP) and have shown that it can increase brain Iron levels in rats following nasal administration. FAC was incorporated into liposomes with high efficiency (97%) and the liposomes were small (40 nm) and stable. Following intranasal delivery in rats, FAC-LIP significantly increased the Iron Content in the olfactory bulb, cerebral cortex, striatum, cerebellum and hippocampus, and was more efficient at doing so than FAC alone. No signs of apoptosis or abnormal cell morphology were observed in the brain following FAC-LIP administration, and there were no significant changes in the levels of SOD and MDA, except in the cerebellum and hippocampus. No obvious morphological changes were observed in lung epithelial cells or tracheal mucosa after nasal delivery, suggesting that the formulation was not overtly toxic. In this study, nanoscale FAC-LIP proved an effective system delivering Iron to the brain, with high encapsulation efficiency and low toxicity in rats. Our studies provide the foundation for more detailed investigations into the applications of niosomal nasal delivery of liposomal formulations of Iron as a simple and safe therapy for Iron deficiency anemia.
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Nasal delivery of nanoliposome-encapsulated ferric ammonium citrate can increase the Iron Content of rat brain
BMC, 2017Co-Authors: Xueling Guo, Hong Zheng, Yuetong Guo, Yan Wang, Gregory J. Anderson, Lina Geng, Yan-zhong ChangAbstract:Abstract Background Iron deficiency in children can have significant neurological consequences, and Iron supplementation is an effective treatment of choice. However, traditional routes of Iron supplementation do not allow efficient Iron delivery to the brain due to the presence of the blood–brain barrier. So an easily delivered Iron formulation with high absorption efficiency potentially could find widespread application in Iron deficient infants. Results In this study, we have developed and characterized a nanovesicular formulation of ferric ammonium citrate (ferric ammonium citrate nanoliposomes, FAC-LIP) and have shown that it can increase brain Iron levels in rats following nasal administration. FAC was incorporated into liposomes with high efficiency (97%) and the liposomes were small (40 nm) and stable. Following intranasal delivery in rats, FAC-LIP significantly increased the Iron Content in the olfactory bulb, cerebral cortex, striatum, cerebellum and hippocampus, and was more efficient at doing so than FAC alone. No signs of apoptosis or abnormal cell morphology were observed in the brain following FAC-LIP administration, and there were no significant changes in the levels of SOD and MDA, except in the cerebellum and hippocampus. No obvious morphological changes were observed in lung epithelial cells or tracheal mucosa after nasal delivery, suggesting that the formulation was not overtly toxic. Conclusions In this study, nanoscale FAC-LIP proved an effective system delivering Iron to the brain, with high encapsulation efficiency and low toxicity in rats. Our studies provide the foundation for more detailed investigations into the applications of niosomal nasal delivery of liposomal formulations of Iron as a simple and safe therapy for Iron deficiency anemia. Graphical abstract The diagrammatic sketch of “Nasal delivery of nanoliposome-encapsulated ferric ammonium citrate can increase the Iron Content of rat brain”. Nanoliposome-encapsulated ferric ammonium citrate (FAC-LIP) was successfully prepared and intranasal administration of FAC-LIP increased both the total Iron Contents and Iron storage protein (FTL) expression in rat olfactory bulb, cerebral cortex, striatum and hippocampus, compared with those of FAC groups. Moreover, there was not overtly toxic affects to brain, lung epithelial cells and tracheal mucosa
Warren S Warren - One of the best experts on this subject based on the ideXlab platform.
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near infrared excited state dynamics of melanins the effects of Iron Content photo damage chemical oxidation and aggregate size
Journal of Physical Chemistry A, 2014Co-Authors: Mary Jane Simpson, Jesse W Wilson, Francisco E Robles, Christopher P Dall, Keely Glass, John D Simon, Warren S WarrenAbstract:Ultrafast pump–probe measurements can discriminate the two forms of melanin found in biological tissue (eumelanin and pheomelanin), which may be useful for diagnosing and grading melanoma. However, recent work has shown that bound Iron Content changes eumelanin’s pump–probe response, making it more similar to that of pheomelanin. Here we record the pump–probe response of these melanins at a wider range of wavelengths than previous work and show that with shorter pump wavelengths the response crosses over from being dominated by ground-state bleaching to being dominated by excited-state absorption. The crossover wavelength is different for each type of melanin. In our analysis, we found that the mechanism by which Iron modifies eumelanin’s pump–probe response cannot be attributed to Raman resonances or differences in melanin aggregation and is more likely caused by Iron acting to broaden the unit spectra of individual chromophores in the heterogeneous melanin aggregate. We analyze the dependence on optical...
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near infrared excited state dynamics of melanins the effects of Iron Content photo damage chemical oxidation and aggregate size
Journal of Physical Chemistry A, 2014Co-Authors: Mary Jane Simpson, Jesse W Wilson, Francisco E Robles, Christopher P Dall, Keely Glass, John D Simon, Warren S WarrenAbstract:Ultrafast pump-probe measurements can discriminate the two forms of melanin found in biological tissue (eumelanin and pheomelanin), which may be useful for diagnosing and grading melanoma. However, recent work has shown that bound Iron Content changes eumelanin's pump-probe response, making it more similar to that of pheomelanin. Here we record the pump-probe response of these melanins at a wider range of wavelengths than previous work and show that with shorter pump wavelengths the response crosses over from being dominated by ground-state bleaching to being dominated by excited-state absorption. The crossover wavelength is different for each type of melanin. In our analysis, we found that the mechanism by which Iron modifies eumelanin's pump-probe response cannot be attributed to Raman resonances or differences in melanin aggregation and is more likely caused by Iron acting to broaden the unit spectra of individual chromophores in the heterogeneous melanin aggregate. We analyze the dependence on optical intensity, finding that Iron-loaded eumelanin undergoes irreversible changes to the pump-probe response after intense laser exposure. Simultaneously acquired fluorescence data suggest that the previously reported "activation" of eumelanin fluorescence may be caused in part by the dissociation of metal ions or the selective degradation of Iron-containing melanin.
Arash Komeili - One of the best experts on this subject based on the ideXlab platform.
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single cell determination of Iron Content in magnetotactic bacteria implications for the Iron biogeochemical cycle
Environmental Microbiology, 2020Co-Authors: Matthieu Amor, Mickael Tharaud, Alexandre Gelabert, Arash KomeiliAbstract:Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that mineralize dissolved Iron into intracellular magnetic crystals. After cell death, these crystals are trapped into sediments that remove Iron from the soluble pool. MTB may significantly impact the Iron biogeochemical cycle, especially in the ocean where dissolved Iron limits nitrogen fixation and primary productivity. A thorough assessment of their impact has been hampered by a lack of methodology to measure the amount of, and variability in, their intracellular Iron Content. We quantified the Iron mass contained in single MTB cells of Magnetospirillum magneticum strain AMB-1 using a time-resolved inductively coupled plasma-mass spectrometry methodology. Bacterial Iron Content depends on the external Iron concentration, and reaches a maximum value of ~10-6 ng of Iron per cell. From these results, we calculated the flux of dissolved Iron incorporation into envIronmental MTB populations and conclude that MTB may mineralize a significant fraction of dissolved Iron into crystals.
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single cell determination of Iron Content in magnetotactic bacteria implications for the Iron biogeochemical cycle
bioRxiv, 2019Co-Authors: Matthieu Amor, Mickael Tharaud, Alexandre Gelabert, Arash KomeiliAbstract:Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that biomineralize dissolved Iron from the envIronment into intracellular nanoparticles of magnetite [Fe(II)Fe(III)2O4] or greigite [Fe(II)Fe(III)2S4] in a genetically controlled manner. After cell death, these magnetite and greigite crystals are trapped into sediments which effectively removes Iron from the soluble pool. MTB may significantly impact the Iron biogeochemical cycle, especially in the ocean where dissolved Iron limits nitrogen fixation and primary productivity. Although MTB are ubiquitous in the envIronment, their impact on the biogeochemical cycling of metallic elements is still poorly constrained. A thorough assessment of the mass of Iron incorporated by MTB has been hampered by a lack of methodology to accurately measure the amount of, and variability in, their intracellular Iron Content. Here, we quantify the mass of Iron contained in single MTB cells of the model organism, Magnetospirillum magneticum sp. AMB-1, using a time-resolved mass spectrometry methodology. Bacterial Iron Content depends on the external Iron concentration, and reaches a maximum value of 10-6 ng of Iron per cell when bacteria are cultivated with initial Iron concentrations of 100 μM or higher. From our experimental results, we calculated the flux of dissolved Iron incorporation into natural MTB populations and conclude that MTB may mineralize a significant fraction of envIronmental dissolved Iron into crystals.
Mark E Haacke - One of the best experts on this subject based on the ideXlab platform.
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assessing global and regional Iron Content in deep gray matter as a function of age using susceptibility mapping
Journal of Magnetic Resonance Imaging, 2016Co-Authors: Manju Liu, Yanwei Miao, Charbel Habib, Saifeng Liu, Kiarash Ghassaban, Weili Zheng, Dane Dicicco, Tarek Jazmati, Mark E HaackeAbstract:Purpose To investigate the correlation of non-heme Iron Content in deep gray matter nuclei as a function of age using quantitative susceptibility mapping (QSM) from both whole-structural and regional perspectives. Materials and methods We studied a group of 174 normal subjects ranging from 20 to 69 years old and measured the magnetic susceptibility of seven subcortical gray matter nuclei. SWI (susceptibility-weighted imaging) phase images were used to generate the susceptibility maps, which were acquired on a 1.5T scanner. The 3D whole-structural measurements were used to determine age-related thresholds, which were applied to calculate the local Iron deposition (RII: portion of the structure that contains Iron concentration larger than the structure threshold). Age-susceptibility correlation was reported for each measured structure for both the whole-region and two-region (low Iron and high Iron Content regions) analysis. Results For the local high Iron Content region, a strong age-susceptibility correlation was found in the caudate nucleus (CN,R = 0.9), putamen (PUT,R = 0.9), red nucleus (RN,R = 0.8), globus pallidus (GP,R = 0.7), substantia nigra (SN,R = 0.5), and pulvinar thalamus (PT,R = 0.5); for the global Iron Content, a strong age-susceptibility correlation was found in CN(R = 0.6), PUT(R = 0.7), and RN(R = 0.6). Overall, for each structure analyzed in this study, regional analysis showed higher correlation coefficient and higher slope comparing to the whole-region analysis. Further, we found the quantitative conversion factor between magnetic susceptibility and Iron concentration to be 1.03 ± 0.03 ppb per μg Iron/g wet tissue. Conclusion We conclude that the age-susceptibility correlation can serve as a quantitative magnetic susceptibility baseline as a function of age for monitoring abnormal global and regional Iron deposition. A regional analysis has shown a tighter age related behavior, providing a reliable and sensitive reference for what can be considered normal Iron Content for studies of neurodegenerative diseases. J. Magn. Reson. Imaging 2016;44:59-71.
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correlation of putative Iron Content as represented by changes in r2 and phase with age in deep gray matter of healthy adults
Journal of Magnetic Resonance Imaging, 2010Co-Authors: Mark E Haacke, Yanwei Miao, Manju Liu, Charbel Habib, Yashwanth Katkuri, Ting Liu, Zhihong Yang, Zhijin LangAbstract:Purpose: To establish a correlation between putative Iron Content using susceptibility weighted imaging (SWI) phase and T2* weighted magnitude values in the basal ganglia and the thalamus as a function of age in healthy human brains. Materials and Methods: One hundred healthy adults (range, 20–69 years; mean, 43 years) were evaluated for this study using a gradient echo sequence. The original magnitude and high pass filtered phase data were analyzed as proxy variables for Iron Content in the substantia nigra, red nucleus, globus pallidus, putamen, caudate nucleus, thalamus, and pulvinar thalamus. Each structure was broken into two parts, a high Iron Content region and a low Iron Content region. Results: Both magnitude and phase data showed an increase in putative Iron Content with age. However, the high Iron Content region revealed two new pieces of information: both the average Iron Content per pixel and the area of high Iron increased with age. Furthermore, significant increase in Iron uptake as a function of age was found past the age of 40. Conclusion: A two region of interest analysis of Iron is a much more sensitive means to evaluate Iron Content change over time. Contrary to the current belief that Iron Content increases level off with age, the putative Iron deposition in the high Iron Content region is seen to increase with age. J. Magn. Reson. Imaging 2010;32:561–576. © 2010 Wiley-Liss, Inc.
Yanwei Miao - One of the best experts on this subject based on the ideXlab platform.
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Iron Content in deep gray matter as a function of age using quantitative susceptibility mapping a multicenter study
Frontiers in Neuroscience, 2021Co-Authors: Sean K Sethi, Yanwei Miao, Chunyan Zhang, Kiran Kumar Yerramsetty, Vinay Kumar Palutla, Sara Gharabaghi, Chengyan Wang, Jingliang Cheng, Fuhua Yan, E M HaackeAbstract:Purpose To evaluate the effect of resolution on Iron Content using quantitative susceptibility mapping (QSM); to verify the consistency of QSM across field strengths and manufacturers in evaluating the Iron Content of deep gray matter (DGM) of the human brain using subjects from multiple sites; and to establish a susceptibility baseline as a function of age for each DGM structure using both a global and regional Iron analysis. Methods Data from 623 healthy adults, ranging from 20 to 90 years old, were collected across 3 sites using gradient echo imaging on one 1.5 Tesla and two 3.0 Tesla MR scanners. Eight subcortical gray matter nuclei were semi-automatically segmented using a full-width half maximum threshold-based analysis of the QSM data. Mean susceptibility, volume and total Iron Content with age correlations were evaluated for each measured structure for both the whole-region and RII (high Iron Content regions) analysis. For the purpose of studying the effect of resolution on QSM, a digitized model of the brain was applied. Results The mean susceptibilities of the caudate nucleus (CN), globus pallidus (GP) and putamen (PUT) were not significantly affected by changing the slice thickness from 0.5 to 3 mm. But for small structures, the susceptibility was reduced by 10% for 2 mm thick slices. For global analysis, the mean susceptibility correlated positively with age for the CN, PUT, red nucleus (RN), substantia nigra (SN), and dentate nucleus (DN). There was a negative correlation with age in the thalamus (THA). The volumes of most nuclei were negatively correlated with age. Apart from the GP, THA, and pulvinar thalamus (PT), all the other structures showed an increasing total Iron Content despite the reductions in volume with age. For the RII regional high Iron Content analysis, mean susceptibility in most of the structures was moderately to strongly correlated with age. Similar to the global analysis, apart from the GP, THA, and PT, all structures showed an increasing total Iron Content. Conclusion A reasonable estimate for age-related Iron behavior can be obtained from a large cross site, cross manufacturer set of data when high enough resolutions are used. These estimates can be used for correcting for age related Iron changes when studying diseases like Parkinson's disease, Alzheimer's disease, and other Iron related neurodegenerative diseases.
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assessing global and regional Iron Content in deep gray matter as a function of age using susceptibility mapping
Journal of Magnetic Resonance Imaging, 2016Co-Authors: Manju Liu, Yanwei Miao, Charbel Habib, Saifeng Liu, Kiarash Ghassaban, Weili Zheng, Dane Dicicco, Tarek Jazmati, Mark E HaackeAbstract:Purpose To investigate the correlation of non-heme Iron Content in deep gray matter nuclei as a function of age using quantitative susceptibility mapping (QSM) from both whole-structural and regional perspectives. Materials and methods We studied a group of 174 normal subjects ranging from 20 to 69 years old and measured the magnetic susceptibility of seven subcortical gray matter nuclei. SWI (susceptibility-weighted imaging) phase images were used to generate the susceptibility maps, which were acquired on a 1.5T scanner. The 3D whole-structural measurements were used to determine age-related thresholds, which were applied to calculate the local Iron deposition (RII: portion of the structure that contains Iron concentration larger than the structure threshold). Age-susceptibility correlation was reported for each measured structure for both the whole-region and two-region (low Iron and high Iron Content regions) analysis. Results For the local high Iron Content region, a strong age-susceptibility correlation was found in the caudate nucleus (CN,R = 0.9), putamen (PUT,R = 0.9), red nucleus (RN,R = 0.8), globus pallidus (GP,R = 0.7), substantia nigra (SN,R = 0.5), and pulvinar thalamus (PT,R = 0.5); for the global Iron Content, a strong age-susceptibility correlation was found in CN(R = 0.6), PUT(R = 0.7), and RN(R = 0.6). Overall, for each structure analyzed in this study, regional analysis showed higher correlation coefficient and higher slope comparing to the whole-region analysis. Further, we found the quantitative conversion factor between magnetic susceptibility and Iron concentration to be 1.03 ± 0.03 ppb per μg Iron/g wet tissue. Conclusion We conclude that the age-susceptibility correlation can serve as a quantitative magnetic susceptibility baseline as a function of age for monitoring abnormal global and regional Iron deposition. A regional analysis has shown a tighter age related behavior, providing a reliable and sensitive reference for what can be considered normal Iron Content for studies of neurodegenerative diseases. J. Magn. Reson. Imaging 2016;44:59-71.
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correlation of putative Iron Content as represented by changes in r2 and phase with age in deep gray matter of healthy adults
Journal of Magnetic Resonance Imaging, 2010Co-Authors: Mark E Haacke, Yanwei Miao, Manju Liu, Charbel Habib, Yashwanth Katkuri, Ting Liu, Zhihong Yang, Zhijin LangAbstract:Purpose: To establish a correlation between putative Iron Content using susceptibility weighted imaging (SWI) phase and T2* weighted magnitude values in the basal ganglia and the thalamus as a function of age in healthy human brains. Materials and Methods: One hundred healthy adults (range, 20–69 years; mean, 43 years) were evaluated for this study using a gradient echo sequence. The original magnitude and high pass filtered phase data were analyzed as proxy variables for Iron Content in the substantia nigra, red nucleus, globus pallidus, putamen, caudate nucleus, thalamus, and pulvinar thalamus. Each structure was broken into two parts, a high Iron Content region and a low Iron Content region. Results: Both magnitude and phase data showed an increase in putative Iron Content with age. However, the high Iron Content region revealed two new pieces of information: both the average Iron Content per pixel and the area of high Iron increased with age. Furthermore, significant increase in Iron uptake as a function of age was found past the age of 40. Conclusion: A two region of interest analysis of Iron is a much more sensitive means to evaluate Iron Content change over time. Contrary to the current belief that Iron Content increases level off with age, the putative Iron deposition in the high Iron Content region is seen to increase with age. J. Magn. Reson. Imaging 2010;32:561–576. © 2010 Wiley-Liss, Inc.
