Measurements of Quenching Rate Constants of Singlet Molecular Oxygen by use of Near Infrared Spectroscopy. Quenching by Cypridina Luciferin Analogues, Luminol and Sodium Azide.

Near-infrared spectroscopy (NIRS) can be used to measure muscle oxygen consumption (mVO2) using arterial occlusions. The recovery rate of mVO2after exercise can provide an index of skeletal muscle mitochondrial function. The purpose of this study was to test the influence of exercise modality and intensity on NIRS measurements of mitochondrial function. Three experiments were performed. Thirty subjects (age: 18–27 yr) were tested. NIRS signals were corrected for blood volume changes. The recovery of mVO2after exercise was fit to a monoexponential curve, and a rate constant was calculated (directly related to mitochondrial function). No differences were found in NIRS rate constants for VOL and ES exercises (2.04 ± 0.57 vs. 2.01 ± 0.59 min−1for VOL and ES, respectively; P = 0.317). NIRS rate constants were independent of the contraction frequency for both VOL and ES (VOL: P = 0.166 and ES: P = 0.780). ES current intensity resulted in significant changes to the normalized time-tension integral (54 ± 11, 82 ± 7, and 100 ± 0% for low, medium, and high currents, respectively; P < 0.001) but did not influence NIRS rate constants (2.02 ± 0.54, 1.95 ± 0.44, 2.02 ± 0.46 min−1for low, medium, and high currents, respectively; P = 0.771). In summary, NIRS measurements of skeletal muscle mitochondrial function can be compared between VOL and ES exercises and were independent of the intensity of exercise. NIRS represents an important new technique that is practical for testing in research and clinical settings.

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Carotenoids, tocopherols and thiols as biological singlet molecular oxygen quenchers

Biochemical Society Transactions ◽

10.1042/bst0181054 ◽

1990 ◽

Vol 18 (6) ◽

pp. 1054-1056 ◽

Cited By ~ 182

Author(s):

PAOLO Di MASCIO ◽

THOMAS P. A. DEVASAGAYAM ◽

STEPHAN KAISER ◽

HELMUT SIES

Keyword(s):

Singlet Oxygen ◽

Molecular Oxygen ◽

Rate Constants ◽

Protective Action ◽

Biological Tissues ◽

Oxygen Quenching ◽

Quenching Rate ◽

Singlet Molecular Oxygen ◽

Singlet Oxygen Quenching ◽

Β Carotene

Singlet molecular oxygen (1O2) has been shown to be generated in biological systems and is capable of damaging proteins, lipids and DNA. The ability of some biological antioxidants to quench 1O2 was studied by using singlet oxygen generated by the thermodissociation of the endoperoxide of 3,3′-(1,4-naphthylidene) dipropionate (NDPO2). The carotenoid lycopene was the most efficient 1O2 quencher (kq + kr = 31 × 109m-1s-1). Tocopherols and thiols were less effective. The singlet oxygen quenching ability decreased in the following order: lycopene, γ-carotene, astaxanthin, canthaxanthin, α-carotene, β-carotene, bixin, zeaxanthin, lutein, bilirubin, biliverdin, tocopherols and thiols. However, the compounds with low quenching rate constants occur at higher levels in biological tissues. Thus, carotenoids and tocopherols may contribute almost equally to the protection of tissues against the deleterious effects of 1O2. The quenching abilities of carotenoids and tocopherols were mainly due to physical quenching. In case of some thiols chemical quenching also plays a significant role. Carotenoids and tocopherols have been reported to exert a protective action against some types of cancer.

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Effectiveness of 6-Ischemic Cuff Near Infrared Spectroscopy Mitochondrial Capactity Test

10.20944/preprints201904.0314.v1 ◽

2019 ◽

Author(s):

Maxwell Sumner ◽

Indrajit Das ◽

Elizabeth K. Pryor ◽

Kevin McCully

Keyword(s):

Infrared Spectroscopy ◽

Near Infrared Spectroscopy ◽

Rate Constants ◽

Near Infrared ◽

Current Method ◽

Data Sets ◽

Curve Fit ◽

Total Data ◽

Mitochondrial Capacity ◽

Analysis Protocol

Near-Infrared Spectroscopy (NIRS) has been used to measure muscle mitochondrial capacity. The current method requires as many as 22 short ischemic occlusions to generate a recovery curve for mitochondrial capacity.  PURPOSE: To determine the effectiveness of using a 6-occlusion analysis protocol to study muscle mitochondrial capacity.  METHOD: Two independent, unidentified data sets were analyzed (bicep n=48, forearm n=41) from previous studies using a NIRS device (Artinis, Ltd.). Both data sets had two recovery tests that included 22 ischemic occlusions.  A recovery rate used to indicate mitochondrial capacity was calculated two different ways (simultaneously).  Each sample was analyzed with a MATLAB program; with a curve-fit for the 22 ischemic occlusions and curve matching for the first six ischemic cuffs and an end resting value. The two resulting rate constants were compared using correlations, both for the two data sets, good and bad fitting data, using the best 5 of 6 points for the 6 cuff approach.  RESULTS: The rate constants were not significantly different between the 22 cmuff and 6 cuff for the total data sets:  bicep (1.43+0.32min-1, 1.44+0.35min-1, p=0.56), forearm (1.94+0.42min-1, 1.95+0.44min-1, p=0.76). The average bicep rate constants, when compared to each other, had an equation of y=1.07x-0.09, R2=0.90. The average forearm rate constants, when compared to each other, had an equation of 0.98x+0.02, R2=0.93. CONCLUSIONS: The 6-Cuff analysis provided the same results as the longer 22-cuff. The 6-cuff approach is both shorter in time and uses less ischemic occlusion periods, increasing the practicality of the NIRS mitochondrial capacity test.

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