Estimation of dehydroascorbic acid in blood of diabetic patients
TL;DR: The DHA from diabetic blood has been isolated as the 2,4-dinitrophenylhydrazone derivative and identified by thin-layer chromatography and spectrophotometry.
About: This article is published in Analytical Biochemistry.The article was published on 1979-10-01. It has received 77 citations till now. The article focuses on the topics: Dehydroascorbic acid & Ascorbic acid.
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TL;DR: Feline spinal cord contains 0.97 mM ascorbic acid, as measured by the dinitrophenylhydrazine method, and greater than 90% is maintained in the reduced form.
Abstract: Feline spinal cord contains 0.97 mM ascorbic acid, as measured by the dinitrophenylhydrazine method. Greater than 90% is maintained in the reduced form. When functioning normally, the CNS conserves its ascorbic acid with a turnover rate of 2% per h. Following contusion injury severe enough to produce paraplegia, ascorbic acid is rapidly lost from injured spinal tissue. Thus, ascorbic acid is decreased 30% by 1 h and 50% by 3 h following injury. Oxidized ascorbic acid is increased at 1, but not 3, h following impact. As a consequence of its many functions in CNS, loss of ascorbic acid may contribute to derangements in spinal cord function following injury.
54 citations
TL;DR: The result of the present study suggests that this DHA disappearance is a function of both a chemical degradation to 2,3-DKG and a reduction to AsA, which indicates that rat plasma lacks an enzyme having an aldonolactonase-like activity.
50 citations
TL;DR: It appears that, in persons having an hereditary predisposition to diabetes, high blood dehydroascorbic acid levels may be used as a marker for early detection of the disease.
Abstract: Ascorbic acid and dehydroascorbic acid were estimated in the blood of normal healthy subjects and diabetic patients. In normal subjects, blood contained only ascorbic acid while dehydroascorbic acid was practically absent. The ascorbic acid level was low in the blood of diabetic patients but the dehydroascorbic acid content was remarkably high, irrespective of age, sex, history of diabetes, or treatment. About 75% of blood dehydroascorbic acid was present in the erythrocytes: the rest was in plasma. High blood dehydroascorbic acid levels were also found in 90% of the non-diabetic offspring with both parents diabetic, in 24% of the non-diabetic offspring with one parent diabetic, and in 75% of the non-diabetic siblings of diabetic patients. It appears that, in persons having an hereditary predisposition to diabetes, high blood dehydroascorbic acid levels may be used as a marker for early detection of the disease.
47 citations
TL;DR: These findings support earlier reports that ascorbic acid uptake into the cell may be compromised by decreased insulin and/or increased extracellular glucose levels and significantly enhanced uptake and reversed the inhibition of glucose.
45 citations
01 Jan 1985
TL;DR: The study of redox enzymes in plasma membranes is at the stage equivalent to looking at distant mountains at dawn through binoculars as discussed by the authors, where fog in the valleys obscures everything except the peaks.
Abstract: The study of redox enzymes in plasma membranes is at the stage equivalent to looking at distant mountains at dawn through binoculars. Fog in the valleys obscures everything except the peaks. What is really there will only be known when the fog is blown away and the mountains stand isolated. Some of the peaks perchance may not be real. As everyone who has walked in mountains knows it might be a long way to the base of the mountain. Along the way are other mountains not appreciated from a distance.
44 citations
References
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01 Jan 1963
TL;DR: Methods of enzymatic analysis, Methods of enzymes analysis, the authors, Methods of enzyme analysis, enzymatics, methods of enzymes, and methods of analysis, method of enzymes.
Abstract: Methods of enzymatic analysis , Methods of enzymatic analysis , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
18,100 citations
TL;DR: Using the in vitro method, the ascorbic acid synthesizing abilities of different species of animals in the phylogenetic tree are examined, and the results are given below.
Abstract: The requirement of ascorbic acid (vitamin C ) is a common property of living organisms, and it has long been considered that all animals except the guinea pig, monkey, and man can synthesize this vitamin. The classic method for determining the ability of an animal to synthesize ascorbic acid is to feed it a scorbutogenic diet for a prolonged period and to observe the appearance of the scurvy syndrome. Obviously, the method is laborious and time-consuming. Also, the onset of the scorbutic syndrome depends on the ascorbic-acid-retention capacity of the animal. For example, whereas the guinea pigs can be made scorbutic in about 3 weeks, it takes 3 to 4 months to produce scurvy in man. Since the discovery of the technique for studying ascorbic acid synthesir in vitro,1-8 the task has become much simpler. In this technique, the tissue homogenates or the subcellular fractions are incubated with precursors of ascorbic acid and the amount of the vitamin formed is estimated. Using the in vitro method, we have examined the ascorbic acid synthesizing abilities of different species of animals in the phylogenetic tree, and the results are given below.
331 citations
TL;DR: Methods for determinations of vitamin C dehydro-Z-ascorbic (DHA), DHA, and DKA in the presence of each other are reported, indicating that these derivatives are identical substances.
268 citations
TL;DR: An account is given of a new method, based on the two findings that homocysteine rapidly reduces dehydroascorbic acid at pH 7 0, and that under certain simple conditions 2:6-dichlorophenolindophenol can be used to estimate ascorbic acid in the presence of homocy steine without interference from the latter compound.
Abstract: Two main methods are in current use for the estimation of dehydroascorbic acid. In the one, developed by Roe and his colleagues (Roe & Kuether, 1943; Roe, Mills, Oesterling & Damron, 1948), the dehydroascorbic acid is condensed with 2:4-dinitrophenylhydrazine and the product treated with sulphuric acid to give a red colour, the intensity of which is measured photoelectrically. In a second technique (Tillmans, Hirsch & Siebert, 1932; Eekelen, Emmerie, Josephy & Wolff, 1933; Bessey, 1938), dehydroascorbic acid is measured as acorbic acid after reduction with hydrogen sulphide and removal of excess of reductant. Disadvantages are associated with both methods; they are nonspecific for dehydroascorbic acid, timeand labourconsuming, and in the method involving reduction with hydrogen sulphide it may be difficult to ensure the removal ofexcess ofreductant before estimating the ascorbic acid formed with 2:6-dichlorophenolindophenol. In this paper an account is given ofanew method, based on the two findings that homocysteine rapidly reduces dehydroascorbic acid at pH 7 0, and that under certain simple conditions 2:6-dichlorophenolindophenol can be used to estimate ascorbic acid in the presence of homocysteine without interference from the latter compound.
124 citations