What are the standard units for Urinary Malondialdehyde relative creatinine?
Is it
umol.g creatinine?
umol.mmol creatinine?
Let me give you the calculation of Professor Pardha-Saradhi. It becomes clear in what units it is necessary to express Malondialdehyde (MDA). This explanation is in RG, by the way.
Please, find below the explanation from Professor Pardha-Saradhi.
(Absorbance at 532) - (Absorbance at 600) is Absorbance due to MDA-TBA abduct.
Extinction coefficient of this MDA-TBA abduct at 532 nm is 155 mM-1cm-1.
Concentration of MDA (mM) = (A532 - A600)/155
Let us presume
(i) A532 is 0.75
(ii) A600 is 0.05
(iii) Volume of reaction mixture is 2 ml (one ml sample + one ml 0.5% TBA in 20% TCA)
(iv) path length is one cm
Concentration of MDA (mM) = (0.75 - 0.05)/155 = 0.6/155 = 0.00387
Concentration of MDA (microM)= 0.00387 x 1000 = 3.87
In other words one microM (means one micromole in 1000 ml) has a value of 3.87. Therefore, one ml reaction mixture will have 3.87/1000 micromole of MDA (= 3.87 nmoles). If reaction mixture is two ml then MDA present in two ml will be 3.87 x 2 = 7.74 nmoles.
Depending on the qualtity of material (irrespective of plant/animal/microbe) you had taken and the quantity of (-%)TCA (or some other solvent) you used for extracting MDA, you need to calculate actual MDA content (either per g fresh or dry weight or some other parameter).
J Chromatogr B Biomed Appl. 1994 Apr 22;655(1):112-6.
Malondialdehyde measurement in urine.
Guichardant M1, Valette-Talbi L, Cavadini C, Crozier G, Berger M.
Author information
Abstract
Malondialdehyde (MDA) is an end product of lipid peroxidation and is a frequently measured index of these processes. The thiobarbituric acid (TBA) test is commonly used to measured MDA, but its specificity is questionable due to the presence of interfering chromogens. Wade and van Rij described in 1988 a method which removes these chromogens by HPLC. However, the sensitivity and the resolution of this method was not adequate for measurements of MDA in urine. We have improved this method by replacing TBA with diethylthiobarbituric acid (DETBA). The less polar MDA-DETBA complexes were isolated on Bakerbond cartridges and quantified by HPLC without interference. MDA was detectable using a fluorescence or ultraviolet detector at picomole levels. This technique was applied to urine samples obtained from ten burns patients on different days following their hospitalization. Urinary MDA in burns patients was very high and reached 18.6 mumol/mmol creatinine in one patient compared with a mean value of 0.23 mumol/mmol creatinine in healthy controls. Maximum MDA levels were attained on the third day for the majority of patients and remained, on average, much higher than normal even after 20 days. Using this method, picomole quantities of MDA can be easily and specifically detected in urine samples. This method is useful for assessing an oxidative stress.
PMID: 8061818
Electron Physician. 2016 Jul; 8(7): 2614–2619.Published online 2016 Jul 25. doi: 10.19082/2614PMCID: PMC5014499PMID: 27648187
Serum and Urinary Malondialdehyde (MDA), Uric acid, and Protein as markers of perinatal asphyxia
"The mean urinary MDA:Cr ratios at birth (2.62 ± 0.29 μg/mg) and after 48 hr (3.70 ± 52 μg/mg) were elevated significantly in newborns with perinatal asphyxia compared to the controls (1.63 ± 0.19 μg/mg vs. 1.96 ± 0.15; P < 0.001)"
Mediators of Inflammation Volume 2015, Article ID 524291, 6 pages http://dx.doi.org/10.1155/2015/524291
Research Article
Urinary Malondialdehyde Is Associated with Visceral Abdominal Obesity in Middle-Aged MenUrinary
MDA was measured with high performance liquid chromatography (HPLC). Urinary MDA levels were expressed as μmol/g creatinine, averaged, and used for analysis.
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