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Biomedical subjects

K F Gey

Publications and source records attributed to K F Gey.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effect of etoposide (VP16-213) on lipid peroxidation and antioxidant status in a high-dose radiochemotherapy regimen.

A total of 13 patients receiving bone marrow transplants (BMT) for treatment of different haematological diseases were investigated. Conditioning therapy preceding BMT consisted of fractionated total-body irradiation (12 Gy) and high-dose chemotherapy with cyclophosphamide (2 +/- 60 mg/kg). Patients stratified to be at high risk for relapse (6/13) were additionally treated with etoposide (30 mg/kg). Plasma concentrations of absolute and lipid-standardized antioxidants (alpha-tocopherol and beta-carotene) decreased following conditioning therapy, presumably as the result of an enhanced breakdown of these antioxidants. Etoposide treatment did not amplify the loss of essential anti-oxidants but significantly increased lipid hydroperoxide concentrations in serum. We suggest that the abnormal generation of lipid hydroperoxides is the result of free radical formation.

Anemia, Aplastic↗
PubMed1989

[Plasma vitamin A and E correlate inversely with coronary mortality].

All essential plasma antioxidants were measured in representative samples of apparently healthy males from 12 European study populations the coronary mortality of which differed by the factor 4. Lipid-standardized vitamins A and E showed a strong inverse correlation to the age-specific coronary mortality (r2 = 0.33 and r2 = 0.49, resp.; combined r2 = 0.53) and thus complemented substantially the direct correlation of coronary mortality with total cholesterol (r2 = 0.51). Multiple regression analysis with these three variables predicted the actual mortality almost completely (r2 = 0.94). In conclusion, a fair plasma status of vitamins A and E could be a quantitatively important, hitherto underrated protective factor of coronary heart disease. These antioxidant vitamins presumably protect lipoproteins against peroxidation and atherogenic modification, respectively, but might still have additional antiarteriosclerotic effects in the arterial wall.

Adult↗
PubMed1989

Plasma vitamin E, apolipoprotein B and HDL-cholesterol in middle-aged men from southern Italy.

Plasma vitamin E, HDL-cholesterol, apolipoprotein B and triglycerides were measured in an apparently healthy, male, random population sample (n = 74) from Southern Italy. Plasma vitamin E concentration was positively correlated to that of serum cholesterol, non-HDL cholesterol, triglycerides and apolipoprotein B (all P less than 0.001). The results of partial correlation analysis showed that apo B, the apolipoprotein constituent of LDL, was related to vitamin E independently of serum triglycerides, a fairly accurate marker of VLDL. On the other hand, triglycerides were related to vitamin E independently of apo B. Both correlations were much weaker if an adjustment was performed for non-HDL-cholesterol. No independent relationship was demonstrated between plasma vitamin E and HDL-cholesterol.

Adult↗
PubMed1989

Plasma vitamins E and A inversely correlated to mortality from ischemic heart disease in cross-cultural epidemiology.

In eight study populations in which the medians of total plasma cholesterol did not differ significantly (mean 5.8 mM, p greater than 0.05) and therefore did not correlate with the IHD mortality (r2 = 0.05), the median of absolute plasma level of vitamin E (alpha-tocopherol) was inversely related to the IHD mortality (r2 = 0.55; p = 0.003). Vitamin A behaved similarly (r2 = 0.51; p = 0.046). The absolute levels of vitamins E and A together with cholesterol predicted (by multiple regression analysis) the IHD mortality of these eight populations fairly well (r2 = 0.81; p = 0.06). Considering all 12 study populations analyzed thus far, total plasma cholesterol correlated with the IHD mortality directly as expected (r2 = 0.51; p less than 0.01), but the median of the plasma alpha-tocopherol individually standardized for cholesterol and triglycerides (220 mg/dL + 110 mg/dL, respectively) maintained a strong inverse association with the IHD mortality (r2 = 0.49; p = 0.01). In the partial regression analysis, lipid-standardized vitamin E exhibited an even stronger inverse correlation with IHD mortality (r2 = 0.69; p less than 0.001). Again, vitamin A behaved similarly to vitamin E, that is, after lipid-standardization of individuals (r2 = 0.33; p = 0.07), as well as in the cholesterol-independent partial regression analysis (r2 = 0.74; p less than 0.001). Both vitamins may act singularly, for after lipid-standardization they vary de facto independently (rs = 0.012) in individuals. The combination of vitamins E and A as obtained by multiple partial regression predicted the actual IHD mortality to a large extent (r2 = 0.89; p less than 0.001), whereas the three-variable prediction model, with the median of total cholesterol and of individually lipid-standardized vitamins E and A, fit the actual IHD mortality of these 12 populations almost completely (r2 = 0.94; p less than 0.001). In conclusion, the plasma status of vitamins E and A are important, hitherto underrated risk factors of IHD, which may act independently, but can, if combined, predict at least 53% of the cross-cultural differences of IHD mortality. After inclusion of total cholesterol into a multivariate model, up to 94% of the IHD mortality can be predicted. The present epidemiological data are in agreement with the hypothesis that these vitamins have physiological functions in the protection of lipoproteins against peroxidation and atherogenic apo-B modifications, respectively, but that does not exclude additional beneficial effects of vitamin E and A in the arterial wall.

Adult↗
PubMed1989

Low plasma vitamins E and C. Increased risk of angina in Scottish men.

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.

Adult↗
PubMed1989

Decreased essential antioxidants and increased lipid hydroperoxides following high-dose radiochemotherapy.

The blood from 19 patients having bone marrow transplantation was examined for the essential antioxidants alpha-tocopherol and beta-carotene as well as lipid hydroperoxides before, at and after bone marrow transplantation (BMT). Conditioning therapy, preceding BMT in order to achieve marrow ablation and immunosuppression, consists of high-dose chemotherapy which is mostly combined with total body irradiation (TBI). In order to see a possible difference between patients with and without additional TBI, we divided the patients up into two groups; patients receiving TBI (RT+) and patients without TBI (RT-). All patients required total parenteral nutrition beginning one week prior to BMT. After conditioning therapy plasma levels of absolute and lipid-standardized alpha-tocopherol and beta-carotene decreased in both groups, presumably as a result of an enhanced breakdown of these antioxidants. The loss of these lipid-soluble antioxidants has to be considered as a possible cause for early post-transplant toxicity. Lipid hydroperoxides increase significantly in the group of patients with additional TBI, whereas the other group, receiving no additional TBI, showed no significant change. We suggest high-dose supplementation of essential antioxidants for patients undergoing BMT.

Adolescent↗
PubMed1989

Inverse correlation of vitamin E and ischemic heart disease.

According to animal experiments, deficiency in vitamin E may be related to arterial lesions. In current cross-cultural epidemiology of middle-aged men representing 11 European populations with different mortality from ischemic heart disease (IHD) all principal antioxidant vitamins and selenium were compared in plasma. The vitamin E concentration within lipoproteins (alpha-tocopherol/cholesterol ratio) showed the most prominent correlation with IHD. This highly significant correlation seemed to be independent of the risk of coronary mortality attributable to hypercholesterolemia. The levels of lipid-standardized vitamin E associated with a relatively higher IHD risk were still in a range which has hitherto been considered "normal." The differences between individuals of lipid-standardized plasma vitamin E were reflected by corresponding changes of vitamin E in the erythrocyte and buccal mucosa. On the other hand, membrane vitamin E varied independently from the level of polyunsaturated fatty acids (PUFAs) in the membrane. The present data suggest that the plasma level of lipid-standardized vitamin E is a hitherto underrated risk factor of IHD which may substantially complement previously known risk factors, such as hypercholesterolemia and a critical state of PUFAs. A conceivable preventive effect of (an enlarged RDA of) vitamin E remains to be elucidated by an intervention trial.

Adult↗
PubMed1987

Relationship of plasma level of vitamin C to mortality from ischemic heart disease.

The present epidemiological data support and extend previous evidence in men and animals. Thus, a poor plasma status of vitamin C (less than 23 microM = 0.4 mg/dl) and/or of cholesterol-standardized vitamin E (less than 20-21.5 microM = 9 mg/l) occurs in westernized countries with an increased risk of IHD. A poor status in the major essential antioxidants may be a hitherto underrated, at least permissive, risk factor of IHD that could, at least in some European countries, substantially complement the previously established risk factors such as hypercholesterolemia.

Adult↗
PubMed1986

Increase of gingival hydroxyproline and proline by improvement of ascorbic acid status in man.

The 4-hydroxyproline and proline content of periodontal tissue was measured in 24 adult volunteers with initially low and partially even deficient plasma vitamin C values, before and after peroral supplementation with 70 mg ascorbic acid daily for six weeks. The latter caused a statistically significant rise and normalization respectively of plasma ascorbic acid and simultaneously a statistically significant increase of the hydroxyproline and proline in periodontal tissue (p less than 0.01) but not before the plasma vitamin C level was above 0.9 mg/dl. The optimal plasma vitamin C level which was associated with the highest hydroxyproline and proline content in periodontal tissue ranged between 1.00-1.30 mg/dl corresponding to the total daily dietary ascorbic acid intake of about 100 mg.

Adult↗
PubMed1983

[Changes in vitamin C content of Bintje potatoes during storage and usual culinary preparations].

In various regions of France (particularly in the North-East) potatoes have remained an important source of vitamin C. We measured by a specific method [7], the loss of ascorbic acid in the Bintje species of potatoes (grown in Pas-de-Calais) due to storage and different cooking procedures. Storage for 3 months in the dark at +12 degrees C decreases the ascorbic acid level by about 50%, storage for 6-8 months by about 66%. Cooking of peeled potatoes (in water, vapor or as French fries) causes an additional loss of vitamin C of roughly 40-45% whereas unpeeled potatoes loose only about 7% by cooking. When cooked potatoes are kept warm, on a hot plate, for an hour the loss of ascorbic acid amounts up to 70%. Thus three major factors determine the spontaneous destruction of ascorbic acid in potatoes, i.e. the length and conditions of storage (aging), the way of cooking and warming up. Potatoes, even when consumed in considerable quantities, can only supply part of the French recommended Daily Allowance [8] particularly from January through June.

Ascorbic Acid↗