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)

The relation between risk of angina pectoris and plasma concentrations of vitamins A, C, and E and carotene was examined in a population case-control study of 110 cases of angina, identified by the Chest Pain Questionnaire, and 394 controls selected from a sample of 6000 men aged 35-54. Plasma concentrations of vitamins C and E and carotene were significantly inversely related to the risk of angina. There was no significant relation with vitamin A. Smoking was a confounding factor. The inverse relation between angina and low plasma carotene disappeared and that with plasma vitamin C was substantially reduced after adjustment for smoking. Vitamin E remained independently and inversely related to the risk of angina after adjustment for age, smoking habit, blood pressure, lipids, and relative weight. The adjusted odds ratio for angina between the lowest and highest quintiles of vitamin E concentrations was 2.68 (95% confidence interval 1.07-6.70; p = 0.02). These findings suggest that some populations with a high incidence of coronary heart disease may benefit from eating diets rich in natural antioxidants, particularly vitamin E.
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PMID:Risk of angina pectoris and plasma concentrations of vitamins A, C, and E and carotene. 167 55

Cross-cultural studies suggest that low plasma antioxidant levels contribute to the high incidence of coronary heart disease (CHD) in Scotland. One hundred twenty-five cases of angina without reported history were identified by a postal WHO chest pain questionnaire from a systemic population sample of 6000 Edinburgh men (35-54 years). Classical CHD risk factors (lipids, blood pressure, smoking, and relative weight), plasma vitamins, and a new independent CHD risk factor, adipose tissue linoleate, were measured in angina (n = 125) and healthy controls (n = 430). Cigarette smoking was common in angina (46% vs. 29%, p less than 0.01), and adipose tissue linoleate was lower (8.77 +/- 0.18% vs. 9.81 +/- 0.14% (p less than 0.01). Classical CHD risk factors were not different. Vitamin E/cholesterol molar ratio (micron/mM) was lower in angina than in controls: 1.58 +/- 0.03 vs. 1.66 +/- 0.02 (p less than 0.01). Plasma vitamin C was also lower in angina than in controls: 23.6 +/- 1.7 vs. 30.5 +/- 1.1 microM (p less than 0.001). The relative risk of angina for those in the lowest versus those in the highest quintile of the vitamin E/cholesterol ratio distribution was 2.2:1, irrespective of other risk factors (p less than 0.009). Adipose tissue linoleate removed the association between vitamin E and angina. The relative risk of angina for those in the lowest versus those in the highest quintile of plasma vitamin C was 2.6:1 (p less than 0.01), and the increased risk was also independent of classical risk factors, but closely related to a smoking habit. Low plasma vitamin E or adipose linoleate predisposes to angina, and smoking may increase the risk of angina by lowering plasma vitamin C levels in Scottish men.
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PMID:Low plasma vitamins E and C. Increased risk of angina in Scottish men. 262 98

Cardiovascular disease (CVD) in general seems to be the leading cause of death in the Eastern Mediterranean Region (EMR) including Iran. This may be due to classic risk factors such as high triglyceride (TG), high total cholesterol (TC), and low levels of high density lipoprotein cholesterol (HDL-C). The impact of antioxidants as potentially protective risk factors against early coronary heart disease (CHD) is unknown in Iran. Therefore, relationships between angina and plasma antioxidants and indicators of lipid peroxidation were investigated in a case-control study. In this study, 82 cases of previously undiagnosed angina pectoris (AP), identified by a modified WHO Rose chest pain questionnaire and verified by electrocardiography during treadmill exercise testing, were compared with 146 controls selected from the same population of over 4000 male civil servants aged 40-60 years. Subjects with AP declared significantly less physical activity and had higher serum TG [means (S.E.M.) 2.32 (0.18) versus 1.61 (0.07) mmol/l] but lower HDL-C [1.01 (0.04) versus 1.18 (0.03) mmol/l] than age-matched controls. Levels of total serum cholesterol, low-density lipoprotein cholesterol (LDL-C) and lipoprotein(a) [Lp(a)] were not significantly different between the two groups, while the ratio of LDL-C/HDL-C was significantly higher [4.51 (0.23) versus 3.54 (0. 11)] for subjects with AP than for the controls. There was no significant difference in plasma levels of alpha-tocopherol, vitamin C, alpha- and beta-carotene. However, retinol [1.90 (0.06) versus 2. 09 (0.05)] and beta-cryptoxanthin [0.398 (0.04) versus 0.467 (0.03)] were significantly lower in AP. Furthermore, angina cases exhibited a higher index of lipid peroxidation than controls (e.g. malondialdehyde, MDA; 0.376 (0.010) versus 0.337 (0.009) micromol/l). On multiple logistic regression analysis, retinol with odds ratio (OR) of 0.644 [95% confidence interval (CI; 0.425-0.978)], beta-cryptoxanthin, with an OR of 0.675 (CI; 0.487-0.940), oxidation indices, MDA with OR of 1.612 (95% CI; 1.119-2.322) and LDL-C/HDL-C ratio with OR of 2.006 (95% CI; 1.416-2.849) showed the most significant independent associations with AP in this group of Iranians. In conclusion, the state of lipid peroxidation as well as the status of special antioxidants may be co-determinants of AP in Iran, in parallel with the influence of classical risk factors for cardiovascular disease.
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PMID:Relationship between classic risk factors, plasma antioxidants and indicators of oxidant stress in angina pectoris (AP) in Tehran. 1085 33

Glyceryl trinitrate (GTN) has found widespread use for the treatment of angina pectoris, a pathological condition manifested by chest pain resulting from insufficient blood supply to the heart. Metabolic conversion of GTN, a nitric oxide (NO) pro-drug, into NO induces vasodilation and improves blood flow. Patients develop tolerance to GTN after several weeks of continuous use, limiting the potential for long-term therapy. The mechanistic cause of nitrate tolerance is relatively unknown. We developed a cell culture model of nitrate tolerance that utilizes stable isotopes to measure metabolism of 15N3-GTN into 15N-nitrite. We performed global metabolomics to identify the mechanism of GTN-induced nitrate tolerance and to elucidate the protective role of vitamin C (ascorbic acid). Metabolomics analyses revealed that GTN impaired purine metabolism and depleted intracellular ATP and GTP. GTN inactivated xanthine oxidase (XO), an enzyme that is critical for the metabolic bioactivation of GTN into NO. Ascorbic acid prevented inactivation of XO, resulting in increased NO production from GTN. Our studies suggest that ascorbic acid has the ability to prevent nitrate tolerance by protecting XO, but not aldehyde dehydrogenase (another GTN bioactivating enzyme), from GTN-induced inactivation. Our findings provide a mechanistic explanation for the previously observed beneficial effects of ascorbic acid in nitrate therapy.
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PMID:Metabolomics-Driven Elucidation of Cellular Nitrate Tolerance Reveals Ascorbic Acid Prevents Nitroglycerin-Induced Inactivation of Xanthine Oxidase. 3031 19

Scurvy is a multisystem condition that arises from vitamin C deficiency. As humans cannot synthesize vitamin C, serum and tissue levels depend on bioavailability, utilization, and renal excretion. Deficiencies result in defective collagen formation with swelling of gums, leg ulceration, and bleeding manifestations. Death most often results from infection and hemorrhage. In a forensic context, scurvy may mimic inflicted injuries and may be responsible for sudden death by mechanisms that remain unclear. Cardiac failure and rhythm disturbances with chest pain, hypotension, cardiac tamponade, and dyspnea are associated with vitamin C deficiency. In addition, syncope and seizures may occur. Although far less common than in previous centuries, scurvy is still present in high-risk populations that include alcoholics, isolated elderly individuals, food faddists, institutionalized patients, those with mental illness, and those who have had bariatric surgery or with underlying gastrointestinal conditions. Scurvy should therefore be a diagnosis to consider in medicolegal cases of apparent trauma and sudden death.
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PMID:Scurvy-Characteristic Features and Forensic Issues. 3042 23

Scurvy is a relatively rare micronutrient deficiency disease that can occur among refugees dependent on food aid (1). Inadequate access to fresh fruits and vegetables in refugee camps can result in scurvy (2,3). Kakuma Refugee Camp in Kenya's Turkana District is home to 148,000 refugees, mostly from Somalia and South Sudan, who receive food assistance. In August 2017, a number of South Sudanese adolescent and young adult male refugees were evaluated at a health clinic in the camp for calf pain, chest pain, and gingival swelling. Because the symptoms were nonspecific, no diagnosis was made, and some patients received antibiotics and analgesics. All were managed as outpatients, but symptoms did not improve. During subsequent months, more young men with similar symptoms were reported. On January 20, 2018, the United Nations High Commissioner for Refugees (UNHCR) was informed and conducted clinical examinations. Signs and symptoms included lower limb pain and swelling (in some cases involving joints), lethargy, fatigue, gingival swelling and pain, hyperkeratotic skin changes, and chest pain. Based on these clinical findings, micronutrient deficiency, particularly vitamin C deficiency (scurvy), was considered a possible diagnosis, and an investigation of a possible outbreak was conducted. The suspected scurvy cases all occurred in young men from South Sudan who were living and cooking together in one geographic section of the camp. All patients who received treatment with vitamin C noted improvement of symptoms within <1 week. Patients were provided with food and cash assistance, the latter to allow dietary diversification (i.e., fresh fruits and vegetables). However, both forms of assistance were inadequate to allow access to sufficient amount of calories and the dietary diversification needed for intake of micronutrients, such as vitamin C. It is important to consider these needs when determining the amount of food or cash assistance provided to adolescents and young adult male refugees.
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PMID:Scurvy Outbreak Among South Sudanese Adolescents and Young Men - Kakuma Refugee Camp, Kenya, 2017-2018. 3067 9