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Anastasova S, Spehar‐Délèze A, Kwasnicki RM, Yang G, Vadgama P. Electrochemical Monitoring of Subcutaneous Tissue pO
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Fluctuations during Exercise Using a Semi‐implantable Needle Electrode. ELECTROANAL 2020. [DOI: 10.1002/elan.202060242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Salzitsa Anastasova
- Institute of Global Health and Innovation Hamlyn Centre Imperial College of Science, Technology & Medicine London W2 1NY UK
- Queen Mary, University of London Mile End Road London E1 4NS UK QMUL
| | | | - Richard Mark Kwasnicki
- Institute of Global Health and Innovation Hamlyn Centre Imperial College of Science, Technology & Medicine London W2 1NY UK
| | - Guang‐Zhong Yang
- Institute of Global Health and Innovation Hamlyn Centre Imperial College of Science, Technology & Medicine London W2 1NY UK
- Institute of Medical Robotics Shanghai Jiao Tong University Shanghai 200040 China
| | - Pankaj Vadgama
- Queen Mary, University of London Mile End Road London E1 4NS UK QMUL
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Hwang SH, Lee DC, Kim DH, Kim BY, Park SH, Lim MH, Jeun JH, Park YH, Kim SW. In vivo Oxygen Condition of Human Nasal Inferior Turbinate-Derived Stem Cells in Human Nose. ORL J Otorhinolaryngol Relat Spec 2020; 82:86-92. [PMID: 31991414 DOI: 10.1159/000504628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/03/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND OBJECTIVE Human nasal inferior turbinate-derived stem cells (hNTSCs) have been considered as a potent and useful source for regenerative medicine. To most effectively mimic the native environment of inferior turbinate could be very effective to hNTSCs biology. Thus, the purpose of this study was to evaluate partial pressure of oxygen (ppO2) and temperature in inferior turbinate. METHODS Ten patients were enrolled who underwent endoscopic endonasal transsphenoidal skull base tumor surgery between January 2014 and December 2015. The commercially available OxyLab pO2 monitor gauges the ppO2 and temperature using a fluorescence quenching technique. Also, hNTSCs were isolated from 10 patients and cultivated under hypercapnic condition (5, 10, and 15%) to mimic hypoxic intranasal conditions. RESULTS The measured oxygen concentration in submucosa tissue was higher than that at the surface of the inferior turbinate and the temperature in submucosa tissue was higher than the value at the surface of inferior turbinate. The patterns of proliferation were significantly different according to hypercapnic cultivation conditions and there were statistically significant decreased proliferation rates after the exposure of higher CO2 over a period of 5 days. CONCLUSIONS Intranasal turbinate tissue showed the hypoxia state in concordance with the result of the other tissues or organs. However, indirectly induced hypoxia influenced the influence on the hNTSCs proliferation negatively. Further study is needed to mimic the real hypoxic state, but our results could be used to optimize the culture environment of hNTSCs, thereby producing the stem cells for regenerative therapies.
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Affiliation(s)
- Se Hwan Hwang
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Dong Chang Lee
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Do Hyun Kim
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Boo-Young Kim
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sun Hwa Park
- Department of Biomedical Science, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Mi-Hyun Lim
- Department of Biomedical Science, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jung Ho Jeun
- Department of Biomedical Science, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Young Hoon Park
- Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sung Won Kim
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea,
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Linsenmeier RA, Zhang HF. Retinal oxygen: from animals to humans. Prog Retin Eye Res 2017; 58:115-151. [PMID: 28109737 DOI: 10.1016/j.preteyeres.2017.01.003] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 01/13/2017] [Accepted: 01/17/2017] [Indexed: 10/20/2022]
Abstract
This article discusses retinal oxygenation and retinal metabolism by focusing on measurements made with two of the principal methods used to study O2 in the retina: measurements of PO2 with oxygen-sensitive microelectrodes in vivo in animals with a retinal circulation similar to that of humans, and oximetry, which can be used non-invasively in both animals and humans to measure O2 concentration in retinal vessels. Microelectrodes uniquely have high spatial resolution, allowing the mapping of PO2 in detail, and when combined with mathematical models of diffusion and consumption, they provide information about retinal metabolism. Mathematical models, grounded in experiments, can also be used to simulate situations that are not amenable to experimental study. New methods of oximetry, particularly photoacoustic ophthalmoscopy and visible light optical coherence tomography, provide depth-resolved methods that can separate signals from blood vessels and surrounding tissues, and can be combined with blood flow measures to determine metabolic rate. We discuss the effects on retinal oxygenation of illumination, hypoxia and hyperoxia, and describe retinal oxygenation in diabetes, retinal detachment, arterial occlusion, and macular degeneration. We explain how the metabolic measurements obtained from microelectrodes and imaging are different, and how they need to be brought together in the future. Finally, we argue for revisiting the clinical use of hyperoxia in ophthalmology, particularly in retinal arterial occlusions and retinal detachment, based on animal research and diffusion theory.
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Affiliation(s)
- Robert A Linsenmeier
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston 60208-3107, IL, USA; Neurobiology Department, Northwestern University, 2205 Tech Drive, Evanston 60208-3520, IL, USA; Ophthalmology Department, Northwestern University, 645 N. Michigan Ave, Suite 440, Chicago 60611, IL, USA.
| | - Hao F Zhang
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston 60208-3107, IL, USA; Ophthalmology Department, Northwestern University, 645 N. Michigan Ave, Suite 440, Chicago 60611, IL, USA.
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Lim JKH, Nguyen CTO, He Z, Vingrys AJ, Bui BV. The effect of ageing on ocular blood flow, oxygen tension and retinal function during and after intraocular pressure elevation. PLoS One 2014; 9:e98393. [PMID: 24866182 PMCID: PMC4035318 DOI: 10.1371/journal.pone.0098393] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 05/02/2014] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To investigate the effect of ageing on the recovery of ocular blood flow, intravitreal oxygen tension and retinal function during and after intraocular pressure (IOP) elevation. METHODS Long Evans rats (3- and 14-month-old) underwent acute stepwise IOP elevation from 10 to 120 mmHg (5 mmHg steps each 3 minutes). IOP was then returned to baseline and recovery was monitored for 2 hours. Photopic electroretinograms (ERG) were recorded at each IOP step during stress and at each minute during recovery. Ocular blood flow and vitreal oxygen tension (pO2) were assayed continuously and simultaneously using a combined laser Doppler flow meter (LDF) and an oxygen sensitive fibre-optic probe, respectively. The combined sensor was placed in the vitreous chamber, proximal to the retina. Data were binned into 3 minute intervals during stress and 1 min intervals during recovery. Recovery data was described using a bi-logistic function. RESULTS Rats of both ages showed similar susceptibility to IOP elevation, with pO2 showing a closer relationship to ERG than LDF. During recovery, both ages showed a distinctive two-phased recovery for all three measures with the exception of the LDF in 3-month-old rats, which showed only 1 phase. In all animals, LDF recovered fastest (<1 minute), followed by pO2 (<10 minute) and ERG (>1 hour). 14-month-old rats showed surprisingly faster and greater LDF recovery compared to the younger group, with similar levels of pO2 recovery. However, the ERG in these middle-aged animals did not fully recover after two hours, despite showing no difference in susceptibility to IOP during stress compared to the young group. CONCLUSIONS Young and middle-aged eyes showed similar susceptibility to IOP elevation in terms of pO2, LDF and ERG. Despite this lack of difference during stress, older eyes did not completely recover function, suggesting a more subtle age-related susceptibility to IOP.
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Affiliation(s)
- Jeremiah K. H. Lim
- Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia
| | - Christine T. O. Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia
| | - Zheng He
- Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia
| | - Algis J. Vingrys
- Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia
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Filas BA, Shui YB, Beebe DC. Computational model for oxygen transport and consumption in human vitreous. Invest Ophthalmol Vis Sci 2013; 54:6549-59. [PMID: 24008409 DOI: 10.1167/iovs.13-12609] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE Previous studies that measured liquefaction and oxygen content in human vitreous suggested that exposure of the lens to excess oxygen causes nuclear cataracts. Here, we developed a computational model that reproduced available experimental oxygen distributions for intact and degraded human vitreous in physiologic and environmentally perturbed conditions. After validation, the model was used to estimate how age-related changes in vitreous physiology and structure alter oxygen levels at the lens. METHODS A finite-element model for oxygen transport and consumption in the human vitreous was created. Major inputs included ascorbate-mediated oxygen consumption in the vitreous, consumption at the posterior lens surface, and inflow from the retinal vasculature. Concentration-dependent relations were determined from experimental human data or estimated from animal studies, with the impact of all assumptions explored via parameter studies. RESULTS The model reproduced experimental data in humans, including oxygen partial pressure (Po2) gradients (≈15 mm Hg) across the anterior-posterior extent of the vitreous body, higher oxygen levels at the pars plana relative to the vitreous core, increases in Po2 near the lens after cataract surgery, and equilibration in the vitreous chamber following vitrectomy. Loss of the antioxidative capacity of ascorbate increases oxygen levels 3-fold at the lens surface. Homogeneous vitreous degeneration (liquefaction), but not partial posterior vitreous detachment, greatly increases oxygen exposure to the lens. CONCLUSIONS Ascorbate content and the structure of the vitreous gel are critical determinants of lens oxygen exposure. Minimally invasive surgery and restoration of vitreous structure warrant further attention as strategies for preventing nuclear cataracts.
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Affiliation(s)
- Benjamen A Filas
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, Missouri
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In Response. J Glaucoma 2013; 22:e24-6. [DOI: 10.1097/ijg.0b013e3182a4a029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Muir ER, Zhang Y, San Emeterio Nateras O, Peng Q, Duong TQ. Human vitreous: MR imaging of oxygen partial pressure. Radiology 2012; 266:905-11. [PMID: 23220896 DOI: 10.1148/radiol.12120777] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop a magnetic resonance (MR) imaging approach to noninvasively image quantitative Po(2) in the human vitreous. MATERIALS AND METHODS Human studies were approved by the institutional review board with informed consent obtained from all subjects and were HIPAA compliant. Animal studies were performed with animal care committee approval. An MR imaging method to measure the longitudinal relaxation rate, or R1, of water was implemented with a 3.0-T MR imager. R1 was calibrated in water phantoms at multiple Po(2) and temperature conditions (n = 10) and in ex vivo animal vitreous (n = 2). Vitreous Po(2) was imaged in three human volunteers (age range, 26-28 years) in multiple sessions on separate days to evaluate reproducibility. The effects of temperature and ambient air were evaluated by acquiring data with the eye open and closed. Statistical analysis consisted of t tests, with P less than .05 indicating significant difference. RESULTS Calibrations of phantoms and ex vivo vitreous yielded an R1 association with oxygen of 0.209 sec(-1) + Po(2) ⋅ 2.07 × 10(-4) sec(-1)/mm Hg at 37°C, and an association with temperature (Δ[1/R1]/ΔTemperature) of 0.106 sec/°C ± 0.009 (standard deviation). A difference in R1 was found between the phantoms and vitreous. If uncorrected, vitreal Po(2) would be significantly overestimated (P < .001). In vivo human vitreous Po(2) maps were spatially heterogeneous, with a whole vitreous Po(2) of 16.7 mm Hg ± 6.5 (eye closed). Measurements between open and closed eyes showed spatially dependent R1 differences, which translated to temperature differences of 0.34°-0.83°C across the eye. CONCLUSION This study established an MR imaging protocol to image quantitative vitreous Po(2) noninvasively and evaluated effects from vitreal macromolecules, temperature gradients, and ambient air on vitreal Po(2) values. Measurement of vitreous Po(2) with MR imaging has the potential to be used to study eye diseases noninvasively.
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Affiliation(s)
- Eric R Muir
- Research Imaging Institute and Department of Ophthalmology, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA
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