Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:EXPT00568 (ascorbate)
 23,072 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In adults supplemental parenteral nutrition (PN) is advisable in burns over 40% especially when weight loss exceeds 10% of body weight. In children with smaller reserves and higher requirement of proteins and energy no rigid scheme for parenteral supplementation is used at our unit. In a young infant it may be added already at a 20-30% deep burn, especially with connected gastrointestinal tract problems, infection etc. Metabolic and protein requirements are estimated 50-100% in addition to their normal needs. Hypertonic glucose (gradually increased from 20-40%), covered with insulin in the early phase, is used as source of carbohydrates. L-amino acid mixture containing the "pediatric essential amino acids" histidine and cysteine is given as a nitrogen source. 20% Intralipid is given in a gradually increased amount of 2-4 g/kg per day to provide calories and essential fatty acids. Among electrolytes K, Ca, P and Mg must be added. Increased amounts of vitamin C and folate are needed by burned children. Vitamin E is also required during prolonged lipid administration. Trace elements (Zn. Fe, etc.) are supplied orally or i.v. with special solutions or fresh plasma infusions. Our experience with parenteral nutrition in severely burned children will be presented. There were no severe metabolic side-effects but sepsis represented the major problem. The concomitant heat preservation by warming the room and use of infra-red heaters is emphasized.
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PMID:Parenteral nutrition in severely burned children. 10 12

A significantly lower vitamin C concentration has been found in the blood and particularly in the leukocytes of hypercholesterolemic diabetic patients than of healthy blood donors. Ascorbic acid administered in a dose of 500 mg per day for 12 months to metabolically stabilized hypercholesterolemic subjects with maturity-onset diabetes mellitus (diabetic diet without insulin or diabetic drugs) brought about a striking decline of cholesterolemia and a moderate decline of triglyceridemia. The serum lipid level in the control group given placebo remained unaltered. A daily administration of 500 mg of ascorbic acid for six months failed to affect the fasting level of serum immunoreactive insulin. It is assumed that the long-term administration of ascorbic acid to maturity-onset diabetics removed the tissue ascorbate deficiency and improved the liver ability to compensate the increased endogenous synthesis of cholesterol by its enhanced transformation to bile acids.
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PMID:Hypocholesterolemic effect of ascorbic acid in maturity-onset diabetes mellitus. 36 79

Vitamin C stimulates the formation of PGE1 in human platelets. The effect occurs over the physiologically relevant range of concentrations. PGE1 is required for T lymphocyte function and plays a major part in the regulation of immune responses. PGE1 is also important in the regulation of collagen and ground substance metabolism, in cholesterol metabolism and in regulation of responsiveness to insulin. It is proposed that defective formation of PGE1 could account for many of the features of scurvy and for many of the reported therapeutic effects of vitamin C. If correct, vitamin C will be of value only in conjunction with an adequate supply of dihomogammalinolenic acid, the precursor of PGE1. Essential fatty acids, pyridoxine and zinc are all required to achieve this.
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PMID:The regulation of prostaglandin E1 formation: a candidate for one of the fundamental mechanisms involved in the actions of vitamin C. 39 Mar 31

The nitrogen metabolism in rats with toxic affection of the liver caused by administration of CCl4 was studied as affected by the amino acid mixture moriamine S-2. It is established that with toxic hepatitis the nitrogen metabolism is sharply disturbed, especially during protein deficiency. The following evidences for this fact: a rise in the depth of the nitrogen negative balance, an increase in the intensity of amine nitrogen and ammonia excretion with urea as well as an increase in the amount of amine nitrogen in blood and tissues with a simultaneous decrease in the content of protein. The parenteral administration of the amino acid mixture for eight days to the animals with a toxic affection of the liver is more effective when nitrogen preparation is combined with the group B vitamin, vitamin C, insulin, nerobolyl and sirepar.
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PMID:[Correction of nitrogen metabolism in rats with toxic hepatitis by parenteral administration of an amino acid mixture]. 42 34

In 19 insulin-dependent diabetics under compensated metabolic conditions the influence of a highly-dosed short-term vitamin C-treatment with 2,000 mg of ascorbic acid on the carbohydrate and fat metabolism was examined during a stay in hospital. Under the treatment with vitamin C low concentrations of blood glucose in the daily profile are observed, in which case this effect of ascorbic acid on the carbohydrate metabolism cannot be statistically ascertained. Triglyceride, cholesterol, FFA-concentrations and glycerol concentrations are not influenced.
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PMID:[The effect of high dosage vitamin C treatment on the carbohydrate and lipid metabolism in diabetics using insulin]. 59 35

An increase in oxidative stress may contribute to the development of diabetic complications. The key aqueous-phase chain-breaking antioxidant ascorbate is known to be deficient in diabetes, and we have therefore investigated the effects of ascorbate supplementation on oxidative stress in the streptozotocin diabetic rat. Markers of lipid peroxidation (malondialdehyde [MDA] and diene conjugates) were increased in plasma and erythrocytes of untreated diabetic animals, and levels of the antioxidants ascorbate and retinol were reduced. Plasma tocopherol was unchanged. Insulin treatment normalized MDA and ascorbate levels, although ascorbate metabolism remained disturbed, as indicated by increased levels of dehydroascorbate. High-dose ascorbate supplementation in the absence of insulin treatment restored plasma ascorbate to normal and increased plasma retinol and tocopherol levels. However, MDA and diene conjugate levels remained unchanged, possibly as a result of increased iron availability. High-dose ascorbate supplementation should be approached with caution in diabetes, as ascorbate may exert both antioxidant and prooxidant effects in vivo.
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PMID:The effect of ascorbate supplementation on oxidative stress in the streptozotocin diabetic rat. 162 52

Cultured pig aortic smooth muscle cells maintain a viable, quiescent state in a chemically defined medium that contains 10(-6) M insulin, 5 micrograms/ml transferrin, and 0.2 mM ascorbate. DNA synthesis and DNA content were determined by measuring tritiated thymidine incorporation and DNA-binding to the fluorescent probe 4',6-diamidino-2-phenylindole, respectively. The majority of the population of cells in defined medium cultures were diploid. Tritiated thymidine uptake in cells in defined medium was one-tenth that observed in cells in fetal bovine serum-containing medium. The study of cellular cyclic AMP level in response to extracellular adenosine stimulation in dividing cells and quiescent cells showed that cells in defined medium had a lower extent of response to adenosine compared to cells cultured in serum-containing medium. Both the cell growth index and the response to adenosine of cells cultured in defined medium were reversible after replacing the medium with 10% fetal bovine serum-containing medium, which suggests that the cells in defined medium were healthy and were capable of modulating cellular metabolism depending on culture conditions.
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PMID:Modulation of response to adenosine in vascular smooth muscle cells cultured in defined medium. 164 62

Several recent studies suggest that vitamin C (ascorbic acid [AA]) status may be altered in insulin-dependent diabetes mellitus (IDDM). We measured the AA content of mononuclear leukocytes (MN-AA) as an indicator of tissue vitamin C status in adults with IDDM and nondiabetic adults matched for age and sex. Dietary vitamin C intake and plasma AA were analyzed to ensure that vitamin C availability was adequate. Dietary vitamin C intakes were above recommendations and were not different between the groups. MN-AA was reduced by 33% on average (P less than .05) in adults with IDDM (1.75 microgram/mg total protein [TP]) when compared with nondiabetics (2.60 micrograms/mg TP). When MN-AA is indexed to the dietary vitamin C intake (MN-AA/100 mg diet C), the storage deficit in adults with IDDM averages 50% (P less than .05). This observation suggests an impaired tissue AA storage in adults with IDDM and supports the theory that intracellular scurvy contributes to the chronic degenerative complications of the disease.
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PMID:Reduced mononuclear leukocyte ascorbic acid content in adults with insulin-dependent diabetes mellitus consuming adequate dietary vitamin C. 198 72

An automatic, luminometric assay of glucose in samples of the extracellular water space obtained by microdialysis is described. The assay involves oxidation by glucose oxidase (EC 1.1.3.4) and mutarotation of glucose by aldose mutarotase (EC 5.1.3.3.). The H2O2 formed is subsequently determined in a reaction catalyzed by horseradish peroxidase (EC 1.11.1.7) using luminol as electron donor. The assay is linear between 0.01 and 1 nmol in the cuvette. The detection limit, defined as 3 standard deviations of the reagent blank, was 0.008 mumol/liter in the cuvette. A complete oxidation of glucose is obtained within 4 min and 25 samples are automatically assayed within 75 min. Addition of microdialysate sample obtained from human adipose tissue in vivo did not interfere with the standard curves. Glucose added to microdialysate resulted in a complete recovery compared to a H2O2 standard. Analytical interference from different factors was investigated. No interference was observed up to the following concentrations: 5 mumol/liter epinephrine, 1 mumol/liter norepinephrine, 100 mumol/liter insulin, 500 mumol/liter pyruvate, 50 mmol/liter lactate, and 1 mumol/liter ascorbate. The glucose values with the present method correlated strongly (r = 0.984) with values obtained using a routine method involving glucose oxidase and peroxidase.
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PMID:Glucose determination in samples taken by microdialysis by peroxidase-catalyzed luminol chemiluminescence. 204 27

Age-related cataract is a condition characterized by multiple mechanisms and multiple risk factors. The mechanisms that bring about a loss in transparency include oxidation, osmotic stress, and chemical adduct formation. Risk factors for cataract include diabetes, radiation (ultraviolet B, x-ray), certain pharmaceutical substances, certain nutritional states, and possibly acute episodes of dehydration. Interaction occurs between and among mechanistic factors and risk factors. Thus nutrition must be considered as one part of a tapestry of intertwined events and responses. Certain experimental models for nutritional cataract have been useful for study of the cataractogenic process but are probably not important factors in the human disease. Little current evidence supports significant roles in human senile cataract for imbalances of tryptophan or other amino acids, deficiencies of calcium or selenium, or excessive intake of selenium. Overconsumption of galactose is likely to be hazardous only in subjects with genetic inability to metabolize this sugar. Vitamins with antioxidant potential (riboflavin, vitamin E, vitamin C, carotenoids) deserve further research scrutiny to ascertain their significance in cataract etiology. Excessive caloric intake needs to receive added emphasis as a factor contributing to cataract. Diabetes increases the likelihood of cataract three- to four-fold. Obesity, defined as more than 20% overweight, is considered a major risk factor for non-insulin-dependent, or type II, diabetes (69, 73). Weight control can be recommended as a prudent, safe, economic, and effective means of lowering risk probability for diabetes and the associated complication of cataract.
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PMID:Nutritional factors in cataract. 220 Apr 64


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