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Biomedical subjects

G Wolfram

Publications and source records attributed to G Wolfram.

At least 37 records · Page 2Linked to original sources
PubMed1999

Influence of folic acid, pyridoxal phosphate and cobalamin on plasma homocyst(e)ine levels and the susceptibility of low-density lipoprotein to ex-vivo oxidation.

Mild hyperhomocyst(e)inaemia is a risk factor for atherosclerotic vascular disease. In-vitro studies have shown that autooxidation of homocyst(e)ine is accompanied by the generation of oxygen radicals. This may lead to oxidative modification of low-density lipoproteins (LDL) and promote atherosclerotic vascular lesions. In male patients with peripheral arterial occlusive disease we determined fasting and post methionine load homocyst(e)ine levels by high performance liquid chromatography and the susceptibility of their LDL particles to ex-vivo oxidation by continously measuring the conjugated diene production induced by incubation with copper ions. Oxidation resistance (expressed as lag time), maximal oxidation rate, and extent of oxidation (expressed of total diene production) of LDL from patients with normal or mildly elevated homocyst(e)ine levels did not differ significantly. Folic acid, pyridoxal phosphate and cobalamin supplementation significantly decreased plasma homocyst(e)ine levels in hyperhomocyst(e)inaemic patients. This went along with a significant decrease in the extent of LDL oxidation and additionally increased HDL-cholesterol levels. The clinical relevance of these findings for the long-term course of atherosclerotic vascular disorders has to be determined by intervention studies.

Adult↗
PubMed1999

Acute effects of LDL-apheresis on cholesterol oxidation products and antioxidants in plasma and lipoproteins of patients with familial hypercholesterolemia.

Regular LDL-apheresis treatment of hypercholesterolemic patients has proven to reduce the formation of atherosclerotic lesions. Regarding the underlying mechanisms, cholesterol oxidation products (COP) may play a detrimental role. Therefore, COP levels were determined before and after regular LDL-apheresis treatment in ten patients with familial hypercholesterolemia. - The patients had approximately twofold elevated plasma and LDL COP concentrations on the average as compared to healthy subjects. LDL-apheresis treatment efficiently removed COP from the circulation. As a consequence of a smaller reduction of the COP content (- 52 %) than of the total cholesterol content (-71 %) in LDL, the LDL COP:cholesterol ratio increased. Lipid-soluble antioxidants in the plasma of the hypercholesterolemics decreased to a comparable extent as did plasma lipids. In contrast to nearly stable vitamin C concentrations, plasma selenium concentrations also decreased, resulting altogether in a decreased but still normal serum total antioxidant capacity. - In conclusion, LDL-apheresis treatment effectively reduced potentially atherogenic COP from the plasma. With normal plasma antioxidant concentrations before LDL-apheresis in long-term treated hypercholesterolemics, the observed acute decrease in lipid-soluble antioxidants and selenium by treatment seems not to be as meaningful. The higher LDL COP:cholesterol ratio after treatment needs further elucidation.

Adolescent↗
PubMed1999

Effects of an antihypertensive medication on functional capacity under simulated flight-typical stress-conditions.

A model to investigate the functional capacity (psychomental performance) under stressful conditions was developed. Twenty eight patients with mild hypertension receiving Nitrendipine (20 mg) for 30 days were tested under hypoxic (16% oxygen) and/or orthostatic (-30 mmHg lower body negative pressure) conditions using a subset of the AGARD battery. The main effect was a decreasing performance of the grammatical reasoning task (GRT) under hypoxia or the combination of hypoxia and orthostasis. A simultaneous application of stressors while performing psychometric test batteries may be useful to reveal pharmaceutical influences on human performance and may help to recommend the use of drugs in occupational medicine.

Aerospace Medicine↗
PubMed1999

Outcome and cost-effectiveness of perioperative enteral immunonutrition in patients undergoing elective upper gastrointestinal tract surgery: a prospective randomized study.

HYPOTHESIS: Perioperatively administered enteral immunonutrition will improve early postoperative morbidity and cost-effectiveness after gastrointestinal tract surgery. DESIGN: A prospective, randomized, double-blind, multicenter clinical trial. SETTING: Surgical departments in German university and teaching hospitals. PATIENTS: One hundred fifty-four patients with upper gastrointestinal tract malignant neoplasms who were eligible for analysis. INTERVENTION: Preoperatively, patients received 5 days of oral immunonutrition (an arginine-, RNA-, and omega3 fatty acid-supplemented diet) or an isoenergetic control diet (1 L/d). Early postoperative enteral feeding with immunonutrition or an isoenergetic, isonitrogenous control diet using a catheter jejunostomy was performed for 10 days. MAIN OUTCOME MEASURES: Postoperative infectious complications, their treatment costs, and cost-effectiveness of immunonutrition were analyzed. Plasma levels of the fatty acids eicosapentaenoic acid and docosahexaenoic acid were measured. RESULTS: In the immunonutrition group, significantly fewer infectious complication events occurred (14 vs 27; P = .05). The number of patients with complications was significantly lower in the supplemented diet group after postoperative day 3 (7 vs 16; P = .04). The treatment costs of complications in the supplemented diet group were suggestively lower than in the control diet group (DM 75172 vs DM 204273). Cost-effectiveness was DM 1503 in the experimental group vs DM 3587 in the control group, where DM denotes deutsche mark (German currency). CONCLUSION: The perioperative administration of an enteral immunonutrition significantly (P = .05) decreased the early occurrence of postoperative infections and reduced substantially the treatment costs of the complications after major upper gastrointestinal tract surgery.

Adjuvants, Immunologic↗
PubMed1999

Dietary fiber reduces the antioxidative effect of a carotenoid and alpha-tocopherol mixture on LDL oxidation ex vivo in humans.

BACKGROUND: Antioxidant concentrations in low density lipoproteins (LDL) are an important determinant for their susceptibility to oxidation and can be modulated by dietary intake. AIM OF THE STUDY: In the present study, the influence of dietary fiber on the antioxidant enrichment and the oxidation resistance of LDL after antioxidant supplementation is investigated. METHOD: An antioxidant supplement consisting of beta-carotene, lycopene, lutein, canthaxanthin and alpha-tocopherol was given to six young women together with a standard meal. Using a cross-over study design, each subject received the standard meal without additional dietary fiber and enriched with pectin, guar, or cellulose in a random order. To determine the resistance of LDL against copper ion-induced oxidation, the formation of conjugated dienes was measured. RESULTS: Eight, 10, and 24 hours after antioxidant supplementation the isolated LDL revealed significantly (p < 0.05) increased antioxidant concentrations; addition of pectin, guar, or cellulose to the meal depressed this increase. Concomitantly, the observed increase in the resistance of LDL against oxidation (measured as lag phase) was lower with dietary fiber supplementation than that found without. On average, pectin, guar, and cellulose reduced the increase of the lag phase (measured without addition of dietary fiber) by 38%, 22%, and 18%, respectively. CONCLUSIONS: These results indicate that dietary fiber supplementation decreases the antioxidative effect of a supplement consisting of carotenoids and alpha-tocopherol in LDL, an effect that is likely to be mediated by a reduced bioavailability of these antioxidants in the gut.

Adult↗
PubMed1999

Scintigraphically assessed cardiac sympathetic dysinnervation in poorly controlled type 1 diabetes mellitus: one-year follow-up with improved metabolic control.

Diabetic neuropathy is thought to comprise a reversible metabolic and an irreversible structural component of neuronal abnormality. To study whether cardiac sympathetic dysinnervation in poorly controlled longer-term Type 1 Diabetes Mellitus (DM) without myocardial perfusion abnormalities is partially reversible with improved metabolic control, 123-I-metaiodobenzylguanidine (123-I-MIBG) scintigraphy (myocardial uptake score 1-6) was performed in 11 Type 1 DM patients (HbA1c 12.0 +/- 1.8%, duration of diabetes 10 +/- 4 yrs) one year after initial assessment. During follow-up, all patients had been treated with intensive insulin therapy and at one year, HbAlc had fallen to 8.4 +/- 1.4% (p < 0.01). The global myocardial 123-I-MIBG uptake score had improved in 5 patients at one year, remained unchanged in 5 patients, and deteriorated in 1 patient. Cardiac sympathetic dysinnervation (123-I-MIBG myocardial uptake (MU) score >2), initially observed in 10 patients, was detectable in 8 patients at follow-up. Myocardial uptake scores of the anterior, lateral, posterior, septal and apical region had improved in 6, 6, 6, 7 and 6 patients, but the mean changes of these scores did not reach significance. In patients with substantial improvement of metabolic control (HbAlc 7.3 +/- 0.6% at one year, mean HbA1c of months 2-12: 7.8%, n = 6), global myocardial uptake had improved from 4.3 +/- 1.0 to 3.2 +/- 1.0 (p < 0.05). Respectively, myocardial uptake score of the anterior, posterior and septal region had ameliorated: 3.8 +/- 1.3 vs 2.3 +/- 0.8 (p < 0.05), 4.0 +/- 1.7 vs 2.5 +/- 1.0 (p < 0.05), 4.3 +/- 1.2 vs 3.2 +/- 1.5 (p < 0.05). In conclusion, cardiac sympathetic dysinnervation in poorly controlled longer-term Type 1 DM patients is dominated by irreversible neuronal abnormalities. Substantial metabolic improvement, however, partially restores cardiac sympathetic dysinnervation, indicating the presence of a reversible component of cardiac sympathetic dysfunction in longer-term Type 1 DM.

3-Iodobenzylguanidine↗
PubMed1999

Some dietary fibers reduce the absorption of carotenoids in women.

Dietary fiber may be partly responsible for the lower bioavailability of carotenoids from food than from purified supplements. Due to the lack of detailed information available, we investigated the effects of different kinds of dietary fiber on the absorption of carotenoids and alpha-tocopherol. Six healthy young women received an antioxidant mixture consisting of beta-carotene, lycopene, lutein, canthaxanthin and alpha-tocopherol together with a standard meal. The meal did not contain additional dietary fiber or was enriched with pectin, guar, alginate, cellulose or wheat bran (0. 15 g. kg body weight(-1)). The increases in plasma carotenoid and alpha-tocopherol concentrations were followed over 24 h, and the areas-under-curves (AUC(24h)) were calculated. The mean AUC(24h) of beta-carotene was significantly (P < 0.05) reduced by the water-soluble fibers pectin, guar and alginate with a mean decrease of 33-43%. All tested fibers significantly reduced the AUC(24h) of lycopene and lutein by 40-74% (P < 0.05). The dietary fiber effect on the AUC(24h) of canthaxanthin was almost significant (P = 0.059) and there was no effect on the AUC(24h) of alpha-tocopherol. We conclude that the bioavailability of beta-carotene, lycopene and lutein given within a mixed supplement is markedly reduced by different kinds of dietary fiber.

Absorption↗
PubMed1998

Effect of a single oral dose of antioxidant mixture (vitamin E, carotenoids) on the formation of cholesterol oxidation products after ex vivo LDL oxidation in humans.

During oxidation of LDL not only polyunsaturated fatty acids and apolipoproteins but also cholesterol is affected. To test the preventive effect of vitamin E and carotenoids against metal ion-induced oxidative modification of the cholesterol moiety, LDL of five females (age 25-30 years) were enriched by single oral supplementation with a mixture of alpha-tocopherol, beta-carotene, lycopene, canthaxanthin, and lutein. LDL was isolated from blood samples before as well as 10 and 24 hours after supplement intake. In the 10 and 24 hours samples, total concentration of the supplemented antioxidants increased significantly to 127% and 125% of the initial value, respectively. As a consequence, the lag phase until beginning of oxidative modification of fatty acids--measured in terms of lag phase time till diene production--significantly increased by 13% (10 h and 24 h). After stopping the oxidation process in all LDL samples (0 h, 10 h, 24 h) of one person when the maximal absorbance value of diene production in the 10 h sample was reached, a statistically significant reduction in the formation of cholesterol oxidation products (COP) could be measured. In the average, 10 h and 24 h after supplementation the COP concentration reached 84% and 86% of the 0 h-value, respectively. Except for 7 beta-hydroxycholesterol, all COP measured decreased by 10-20%. The results of the in vitro-model demonstrate that an antioxidant enrichment of LDL has the potential to protect also cholesterol (besides unsaturated fatty acids) against oxidative modification.

Administration, Oral↗
PubMed1998

Evidence for specific autoimmunity against sympathetic and parasympathetic nervous tissues in Type 1 diabetes mellitus and the relation to cardiac autonomic dysfunction.

There is growing evidence for the involvement of immunological factors in the pathogenesis of cardiac autonomic dysfunction in Type 1 diabetes mellitus (DM). To evaluate the presence of autoantibodies against autonomic nervous tissues and their relationship with tests of autonomic function, 64 newly diagnosed and 142 long duration Type 1 DM patients were investigated for sympathetic and parasympathetic ganglia (CF-SG and CF-PSG) autoantibodies with a complement-fixing indirect immunofluorescence technique. Five cardiac reflex tests were performed to assess autonomic function. Fifty-seven patients with neurological diseases other than diabetic neuropathy and 131 healthy control subjects were also tested for CF-SG and CF-PSG autoantibodies. CF-SG autoantibodies were observed in 47 (23%) and CF-PSG autoantibodies in 21 (10%) of 206 Type 1 DM patients (p < 0.001). In contrast, these autoantibodies were detected in 3 (5%) and 1 (2%) of patients with non-diabetic neurological diseases and 3 (2%) and 4 (3%) of control subjects (p < 0.01, p < 0.05, p < 0.0001, p < 0.05 vs Type 1 DM patients). All except two Type 1 DM patients with CF-PSG autoantibodies also presented with CF-SG autoantibodies. In diabetic patients with long duration, CF-SG autoantibodies were more frequent in patients with ECG-based cardiac autonomic neuropathy (CAN; > or =2 of 5 cardiac reflex tests abnormal) compared to patients without CAN although this did not reach statistical significance (29% vs 17%, p = 0.06). However, 4 (80%) of 5 newly diagnosed and 23 (32%) of 73 established Type 1 DM patients with abnormalities in heart rate variation during deep breathing and/or standing from lying presented with CF-SG autoantibodies compared to 12 (25%) of 58 newly diagnosed (p < 0.05) and 7 (11%) of 63 established Type 1 DM patients (p < 0.01), in whom both tests were normal. The results suggest that autoimmune factors contribute to the pathogenesis of cardiac autonomic dysfunction in Type 1 DM and that autoantibodies against sympathetic and parasympathetic nervous tissues are relatively specific for Type 1 DM.

Adult↗
PubMed1998

Iodine supplementation of laying hen feed: a supplementary measure to eliminate iodine deficiency in humans?

Iodine deficiency still exists in many countries worldwide, to a certain degree this is also true for Germany. Food of animal origin can be a good source for iodine depending on the feed. To investigate the possible use of laying hen feed enriched with iodine, we conducted a feeding experiment with 40 laying hens receiving feed with different amounts of iodine either as KIO3 or in the form of seaweed. Iodine concentration in eggs increased significantly depending on iodine intake after a 2 week period. Seaweed could also be used as an iodine source by the hens. A subsequent consumption study with 24 volunteers showed that eggs enriched with iodine can increase human's iodine excretion and therefore improve human's iodine supply. This new strategy is thought to accompany salt iodization programs, not to replace them.

Animals↗
PubMed1998

[Phenolic acid intake of adults in a Bavarian subgroup of the national food consumption survey].

Phenolic acids, essentially hydroxycinnamic acids and hydroxybenzoic acids, are secondary plant products and commonly found in plant derived foodstuff. The antioxidant and anticarcinogenic properties of phenolic acids could be one of the facts to explain the inverse association between fruit and vegetable intake and the incidence of coronary heart disease and cancer, respectively, as found in epidemiologic studies. Phenolic acids are rarely listed in food composition tables and there are no dietary intake data available. Consequently, a data base containing the phenolic acid content of foods (literatur data) was built and 7-d dietary protocols of 63 women and 56 men of a Bavarian subpopulation (age 19-49 years) of the German National Food Consumption Survey (NVS) were evaluated. The average phenolic acid intake of men and women is 222 mg/d within a large range. The dominating one within all the phenolic acids is clearly caffeic acid (206 mg/d); the intake of the other phenolic acids amounts to 0.2 (gentisic acid) up to 5.2 mg/d (ellagic acid). The sum of hydroxybenzoic acids and hydroxycinnamic acids amounts to 11 mg/d and 211 mg/d, respectively. Significant sex differences are found for some of the phenolic acids. Especially, the average intake of caffeic acid of women (229 mg/d) is higher than that of men (179 mg/d) caused by the high amount of coffee consumption. The age group "25-49 years" is consuming more coffee than the age group "19-24 years" and, therefore, reveals a significantly higher intake of caffeic acid. The major sources of phenolic acids are coffee with 92% of the caffeic acid intake and fruits (including fruit products and juices) with 75% of the salycilic acid and 59% of the p-coumaric acid intake. Consequently, phenolic acids are consumed in considerable amounts with food. Since antioxidant and anticarcinogenic properties of phenolic acids are already proven in in vitro as well as in animal experiments, epidemiologic studies will show whether a high phenolic acid intake goes ahead with a reduced risk for coronary heart disease or cancer in humans.

Acids, Carbocyclic↗
PubMed1998

Sucrose intake in Germany.

The present investigation reevaluated the German National Food Consumption Survey in order to obtain data on sucrose intake and food sources of sucrose intake in Germany. Moreover, it focused on the effect of sucrose intake on nutrient intake. By means of the food composition data base Bundeslebensmittelschlüssel, version II.2, 7-days dietary records of a representative sample of 15,838 persons aged 4 years and older were analyzed. The relation between sucrose and nutrients intake was investigated by variance and regression analyses. Low, moderate, and high sucrose intake categories were defined by means of sucrose density quartiles and comparisons were made for the percentages of persons meeting the German nutrient intake recommendations. Mean daily sucrose intake ranges between 43.2 g/d (f, 51-64 years) and 82.3 g/d (m, 13-14 years). The mean contribution of sucrose to total energy intake is highest with 14% in young age (4-6 years) and decreases to 9% and 7% in 51-64 year old women and men, respectively. The food groups "table sugar", "confectionery and ice cream", "biscuits, cake and pastries", "preserves", "dairy products", and "non-alcoholic beverages" are the main sucrose sources with varying importance in different age groups. The average amount of naturally occurring sucrose in the Germans' diet is estimated to 15-25% of total sucrose intake. Sucrose contributes 80-90% to total disaccharides intake in Germany. With each gram of sucrose the intake of energy rises on the average by 12.5 kcal (52.4 kJ), of protein by 0.3 g (9% of the energy increase), of fat by 0.5 g (34%), and of carbohydrates by 1.8 g (57%). Consequently, the higher the sucrose content of a diet, the lower is the contribution of fat to total energy intake. In contrast, the energy-adjusted effect of sucrose was found to be negative for energy-providing nutrients (except mono- and disaccharides) as well as for all the selected micronutrients, except calcium, vitamin E, vitamin C, and dietary fiber. Accordingly, the comparison between moderate and high sucrose consumers revealed a lower percentage of persons meeting nutrient intake recommendations in the high sucrose category under the condition of a comparable energy intake. This unfavorable effect of high sucrose intake is most prominent in 4-6 year old boys and girls as the groups with the highest sucrose intake. Since from the present data no exact figure for a sucrose or sugars intake recommendation can be deduced, it is suggested to keep on the WHO recommendation for a moderate sugar intake of 10% of energy intake.

Adolescent↗
PubMed1998

Influence of different fat emulsions with 10 or 20% MCT/LCT or LCT on lipoproteins in plasma of patients after abdominal surgery.

In patients after elective abdominal surgery, different fat emulsions were used to compare their efficacy in total parenteral nutrition and in normalizing plasma lipoprotein levels. In five different groups with 5 patients each, half of the nonprotein calories were given as medium-chain triglycerides/long-chain triglycerides (1:1) or as long-chain triglycerides alone in 10 or 20% fat emulsions or as glucose alone in a control group for 7 days. After surgery, an initial decrease of all plasma lipoprotein components was followed by a different behavior of glyceride-glycerol, cholesterol, phospholipids, and apolipoproteins. Glyceride-glycerol in very-low-density lipoproteins and high-density lipoproteins is increasing during infusion of fat emulsions and decreasing during overnight interruption of infusions. After the 7-day infusion period, there was no significant difference in very-low-density lipoprotein glyceride-glycerol as compared with the values before different infusions. Low-density lipoprotein cholesterol is reaching and exceeding preoperative concentrations between the 4th and the 7th day, most during infusion of 10% fat emulsion and especially due to an increase of free cholesterol. High-density lipoprotein cholesterol and apolipoprotein A-I reach preoperative levels during infusion of fat emulsions but not with glucose alone. Higher than preoperative values are reached in phospholipids with all fat infusions already on day 4. Abnormal lipoprotein X occurred least with the medium-chain/long-chain triglyceride 20% fat-infusion. This fat emulsion is suggested as having the best normalizing effect on plasma lipoproteins and best tolerance in patients after surgery.

Abdomen↗
PubMed1998

Absorption of cholesterol oxidation products from ordinary foodstuff in humans.

BACKGROUND: Information on the absorption of cholesterol oxidation products (COP) from ordinary foodstuff in humans is scarce. METHODS: Five healthy young men were offered a salami- and Parmesan-containing meal naturally rich in COP. Plasma and lipoprotein COP concentrations were measured over the following 9 h. RESULTS: The mean plasma free (nonesterified) COP concentration showed its maximal increase 3 and 5 h after meal consumption. In contrast, the raise in plasma total COP concentration began 6 h after the meal with a maximum at 8 h and was statistically significant for 7alpha- and 7beta-hydroxycholesterol and 7-ketocholesterol. The increase in plasma total cholesterol concentration was comparable to that of total COP. Comparing the COP composition of the chylomicrons and the test meal, cholestanetriol, 7-ketocholesterol, and to a lesser extent cholesterol-alpha-epoxide were underrepresented in the chylomicrons as was the opposite for 7beta-hydroxycholesterol. In very-low-density lipoprotein, a steady increase in the COP:cholesterol ratio was observed from 6 h on. CONCLUSION: COP from ordinary foodstuff were absorbed in the human intestinal tract but differences in the bioavailability of the single COP compounds were found.

Absorption↗
PubMed1998

Effects of elevated carbon dioxide environment on calcium metabolism in humans.

BACKGROUND: Chronic respiratory acidosis induced by an elevated carbon dioxide (CO2) environment should provoke hypercalciuria with related total body and subsequent bone calcium losses. We examined this hypothesis in four healthy male volunteers, who were exposed during a 25-d period to an 0.7% CO2 environment within a deep diving isolation chamber. Three months later the same subjects were reexamined during a second campaign being exposed to a 1.2% CO2 atmosphere. METHODS: The subjects received a constant calcium intake (1.4 g.d-1) and vitamin D supplement (1000 IU.d-1) during both campaigns. Calcium balance (oral calcium intake minus urinary and fecal calcium output) was evaluated. Serum calcium concentrations and biomarkers of bone metabolism were measured, in order to evaluate bone turnover. Additionally, the response to an acute oral calcium load was examined as a sensitive measure of changes in calcium metabolism. RESULTS: Both, urinary calcium excretion (from 245 +/- 38 to 199 +/- 31 mg.d-1; mean +/- SE, 0.7% and 1.2%, respectively) and fecal calcium losses (from 1229 +/- 128 to 996 +/- 62 mg.d-1) were significantly reduced in the higher (1.2%) CO2 atmosphere. Although more calcium was retained in the body during the 1.2% than during the 0.7% CO2 campaign, serum calcium concentrations and biomarkers of bone formation were significantly lower in the higher CO2 campaign. Furthermore, bone resorption was slightly increased in the 1.2% experiment. CONCLUSION: Elevated CO2 atmosphere may dose-dependently preserve body calcium without a parallel improvement of bone substance.

Acidosis, Respiratory↗