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R Bitsch

Publications and source records attributed to R Bitsch.

At least 19 recordsLinked to original sources
PubMed2005

Urinary pharmacokinetics of cyanidin glycosides in healthy young men following consumption of elderberry juice.

We investigated the urinary pharmacokinetics of monomeric anthocyanins in seven healthy volunteers. The volunteers were administered a single oral dose of 3.57 g total anthocyanins contained in 150 ml of a concentrated elderberry juice under fasting conditions. Within 24 h the urinary excretion of unchanged cyanidin-3,5-diglucoside (cyanidin-3-sambubioside-5-glucoside and cyanidin-3,5-diglucoside were calculated as cyanidin-3,5-diglucoside equivalents), cyanidin-3-glucoside, cyanidin-3-sambubioside and total anthocyanins (i.e., the sum of all quantifiable anthocyanidin glycosides) was 0.16, 0.06, 0.05 and 0.06% of the administered doses, respectively. Maximum excretion rates were determined within 1.0 h after intake. The estimates (arithmetic mean +/- SD) of t1/2 were 1.25 +/- 0.25, 1.53 +/- 0.36, 1.38 +/- 0.20 and 1.35 +/- 0.18 h for cyanidin-3,5-diglucoside, cyanidin-3-glucoside, cyanidin-3-sambubioside and total anthocyanins, respectively. The urinary excretion of intact anthocyanins was fast and the decline of excretion rates appeared to be monophasic, suggesting a one-compartment pharmacokinetic model. The low urinary excretion of dietary anthocyanidin glycosides with values below 1% indicates that a large proportion of these plant pigments consumed are metabolized before entry into the circulation.

Adult↗
PubMed2002

Assessment of antioxidant activity by using different in vitro methods.

In this study, six common tests for measuring antioxidant activity were evaluated by comparing four antioxidants and applying them to beverages (tea and juices): Trolox equivalent antioxidant capacity assay (TEAC I-III assay), Total radical-trapping antioxidant parameter assay (TRAP assay), 2,2-diphenyl-l-picrylhydrazyl assay (DPPH assay), N,N-dimethyl-p-phenylendiamine assay (DMPD assay), Photochemiluminescence assay (PCL assay) and Ferric reducing ability of plasma assay (FRAP assay). The antioxidants included gallic acid representing the group of polyphenols, uric acid as the main antioxidant in human plasma, ascorbic acid as a vitamin widely spread in fruits and Trolox as water soluble vitamin E analogue. The six methods presented can be divided into two groups depending on the oxidising reagent. Five methods use organic radical producers (TEAC I-III, TRAP, DPPH, DMPD, PCL) and one method works with metal ions for oxidation (FRAP). Another difference between these tests is the reaction procedure. Three assays use the delay in oxidation and determine the lag phase as parameter for the antioxidant activity (TEAC I, TRAP, PCL). They determine the delay of radical generation as well as the ability to scavenge the radical. In contrast, the assays TEAC II and III, DPPH, DMPD and FRAP analyse the ability to reduce the radical cation (TEAC II and III, DPPH, DMPD) or the ferric ion (FRAP). The three tests acting by radical reduction use preformed radicals and determine the decrease in absorbance while the FRAP assay measures the formed ferrous ions by increased absorbance. Gallic acid was the strongest antioxidant in all tests with exception of the DMPD assay. In contrast, uric acid and ascorbic acid showed low activity in some assays. Most of the assays determine the antioxidant activity in the micromolar range needing minutes to hours. Only one assay (PCL) is able to analyse the antioxidant activity in the nanomolar range. Black currant juice showed highest antioxidant activity in all tests compared to tea, apple juice and tomato juice. Despite these differences, results of these in vitro assays give an idea of the protective efficacy of secondary plant products. It is strongly recommended to use at least two methods due to the differences between the test systems investigated.

Antioxidants↗
PubMed2001

Bioactive anthocyanins detected in human urine after ingestion of blackcurrant juice.

Anthocyanins are a group of very efficient bioactive compounds that are widely distributed in plant food. Several fruits (blackcurrant, blackberry, red grape) and some vegetables (eggplant, onion, red radish) are rich sources of these natural pigments. Extracts of some of them are used as food colorants as well as components of pharmaceutical preparations and functional foods. Anthocyanins, through their ability to inhibit radical reactions, are considered to exert several protective effects in the human body. Until now there has been only a small amount of data available on their capability, in intact or metabolized form, to reach the systemic circulation of humans. The present study was designed to determine the potential bioavailability in humans of the most important anthocyanins of blackcurrants: delphinidine-3-glucoside, delphinidine-3-rutinoside, cyanidine-3-glucoside, and cyanidine-3-rutinoside. Urinary samples from 4 healthy volunteers (2 women and 2 men) were collected before (baseline) and over a period of 5 hours with intervals of 30 minutes after the ingestion of 200 mL of blackcurrant juice (containing 153 mg of anthocyanins). Using high-performance liquid chromatography (HPLC), it was possible to quantify the 4 main anthocyanins of blackcurrants, excreted unchanged in the urine (0.020-0.050% of the oral doses). We present data on the bioavailability in humans of blackcurrant anthocyanins, which are dietary antioxidants with possible biological effects.

Adult↗
PubMed2000

High thiamine diphosphate concentrations in erythrocytes can be achieved in dialysis patients by oral administration of benfontiamine.

OBJECTIVE: The influence of either orally administered S-benzoylthiamine-O-monophosphate (benfotiamine) or thiamine nitrate on the thiamine status was tested in a randomised, two-group comparison study in 20 end-stage renal disease (ESRD) patients. Main outcome measures were the pharmacokinetics of thiamine diphosphate (TDP) in blood, the in vitro erythrocyte transketolase activity, its activation coefficient (alpha-ETK) and the TDP concentration in erythrocytes. METHODS: After ingestion of a single dose of either 100 mg thiamine nitrate (corresponding to 305 micromol thiamine) or 100 mg benfotiamine (corresponding to 214 micromol thiamine), the blood levels of thiamine phosphate esters were analysed by means of high-performance liquid chromatography for a 24-h period. The TDP concentration in erythrocytes was calculated using the haematocrit and TDP concentration in blood. Erythrocyte transketolase activity and alpha-ETK were measured before and 10 h after administration. The pharmacokinetics of TDP in blood were compared with healthy subjects of other studies retrieved from database query. RESULTS: Regarding the blood concentrations of TDP, the patients with ESRD had a 4.3 times higher area under the concentration time curve after benfotiamine administration than after thiamine nitrate. After benfotiamine administration, the peak plasma concentration of TDP exceeded that in healthy subjects by 51%. In the ESRD patients, after 24 h, the mean TDP concentration in erythrocytes increased from 158.7+/-30.9 ng/ml initially to 325.8+/-50.9 ng/ml after administration of benfotiamine and from 166.2+/-51.9 ng/ml to 200.5+/-50.0 ng/ml after thiamine nitrate administration. The ratio between the maximum erythrocyte TDP concentration and basal concentration was 2.66+/-0.6 in the benfotiamine group and 1.44+/-0.2 in the group receiving thiamine nitrate (P < 0.001). After 24 h, it was 2.11+/-0.4 and 1.23+/-0.2, respectively. The transketolase activity increased from 3.54+/-0.7 microkat/l initially to 3.84+/-0.6 microkat/l after benfotiamine intake (P = 0.02) and from 3.71+/-0.8 microkat/l to 4.02+/-0.7 microkat/l after thiamine nitrate intake (P = 0.08). Likewise, alpha-ETK decreased from initially 1.10+/-0.07 to 1.04+/-0.04 (P = 0.04) and from 1.12+/-0.05 to 1.08+/-0.06 (P = 0.09). After 24 h, the phosphorylation ratio in whole blood decreased from 12.9+/-6.9 initially to 5.6+/-3.2 after benfotiamine administration (P = 0.02) and from 13.5+/-7.3 to 9.0+/-4.8 (P = 0.03) after administration of thiamine nitrate. No correlation between erythrocyte TDP concentration and transketolase activity and/or alpha-ETK was observed in ESRD patients, either before or 10 h after administration. CONCLUSION: Compared with thiamine nitrate, the oral administration of benfotiamine leads to higher TDP concentrations in erythrocytes accompanied with a significant improvement of the erythrocyte transketolase activity in ESRD patients.

Administration, Oral↗
PubMed2000

Assessment of thiamin status in chronic renal failure patients, transplant recipients and hemodialysis patients receiving a multivitamin supplementation.

The thiamin status of patients with chronic renal failure (CRF, n = 14), dialysis patients (DP, n = 24) and patients after renal transplantation (RT, n = 19) was assessed. Thiamin intake was calculated at mean levels of 1.26 mg/d (CRF), 0.83 mg/d (DP) and 1.42 mg/d (RT). Corresponding mean plasma concentrations were 64.2 nmol/l (CRF), 78.3 nmol/l (DP) and 55.1 nmol/l (RT). Thiamin supplements of 1.5 mg or 8.0 mg orally given to patients of the DP-group after each dialysis session showed slightly higher thiamin concentrations in plasma. Transketolase activity coefficients (ETK-AC) were in the same range (1.11...1.19) except for RT-patients who had a slightly but not significantly higher ETK-AC of 1.22. During dialysis treatment (DT), thiamin plasma concentrations dropped to 75 and/or 82% in patients supplemented with 1.5 and/or 8.0 mg. They both reached initial levels again 44 hours later. Despite large inter-individual differences, thiamin concentrations increased in the non-supplemented DP-group. ETK-AC did not change after a 14-day interruption of supplementation and did not deteriorate after a single dialysis session, both in supplemented and non-supplemented patients. A daily thiamin supplementation which complies with the RDA for healthy subjects is indicated in DP and is sufficient to keep thiamin status within the normal range.

Adult↗
PubMed2000

Does a 100-km walking affect indicators of vitamin status?

The status of thiamin (B1), riboflavin (B2), ascorbic acid (AA), and tocopherol was determined in 60 leisure athletes (age 46 +/- 10 y, BMI 23.7 +/- 2.0 kg.m-2, VO2max 39.4 +/- 6.5 ml.min-1.kg-1), who completed a 100-km walking race. Vitamin plasma levels and activities of erythrocyte transketolase (ETK) and glutathione reductase (EGR) were measured before start, immediately after finishing and 6 hours later. The participators finished the entire distance in 14.25 h (average speed 7 km.h-1). Before start, all participators showed an excellent vitamin status (prevalences of low vitamin status ranged between 1.7 and 1.8%). Plasma tocopherol concentrations correlated significantly with increased age (r = 0.35, p = 0.008). Compared to the values before start, plasma concentrations of B1 and B2 as well as ETK and/or EGR were increased significantly after finishing. The raised levels persisted 6 hours after finishing, whereas AA remained unaltered. The univariate analysis of variance revealed that the change in vitamin status after finish and 6 hours later was in part highly dependent on age, BMI and the level of physical fitness. Despite the long distance, the extensive character of the 100-km walking with its low intensity did not deteriorate the measured indicators of vitamin status.

Adult↗
PubMed2000

Bioavailability of water- and lipid-soluble thiamin compounds in broiler chickens.

The bioavailability of thiamin mononitrate, thiamin chloride-hydrochloride and benfotiamin was compared in broiler chickens. A thiamin-deficient diet was supplemented with either 1.8 and 1.5 mg/kg thiamin equivalent as water-soluble salts, or with 1.5 and 1.2 mg/kg thiamin equivalent as benfotiamin, respectively, and fed to 3 replicate groups/treatment for 21 days. Weight gain, feed consumption and feed conversion rate were not significantly affected by solubility or dietary level of thiamin. Likewise, using biochemical indices of thiamin status (erythrocyte transketolase activation coefficient, and thiamin concentrations in blood and liver), no differences were found between the water-soluble thiamin salts, indicating that they have identical potency. In contrast, biochemical indices of thiamin status showed a significantly higher bioavailability for benfotiamin than for the water-soluble sources.

Animals↗
PubMed1999

Intestinal absorption of lycopene from different matrices and interactions to other carotenoids, the lipid status, and the antioxidant capacity of human plasma.

BACKGROUND: The bioavailability of carotenoids has been investigated in animal studies as well as in human studies, so far mostly for beta-carotene. Only few results exist for lycopene. In recent studies, lycopene was significantly better available from processed tomatoes compared to raw tomatoes, when using daily intakes between 16.5 mg and 75 mg lycopene. AIM OF THE STUDY: In a comparative study the availability of a low oral lycopene dosage of 5 mg/d from different food matrices versus soft gel capsules containing tomato oleoresin was assessed. In addition to the plasma carotenoid content, the effect of lycopene ingestion on other plasma carotenoids, the lipid status parameters, and the antioxidant activity was estimated. METHODS: Twenty-two female adults (20-27 y) were randomized in three groups and were advised to minimize their carotenoid intake for two weeks. After this initial period, two groups received a portion of tomatoes or tomato juice adjusted to a lycopene dose of 5 mg/d, the third group ingested the same dose comprised in soft gel capsules containing tomato oleoresin. During the test period of 6 weeks, the participants continued reducing the intake of carotenoids from food. Fasting blood samples were withdrawn prior to the study, before supplementation started, and then weekly while supplemented. Seven-day dietary records were prepared before the study started and after one week of supplementation. Carotenoids were analyzed by reversed phase HPLC with diode array detection. Dietary records were evaluated using the computer software EBIS 2.1. The plasma total cholesterol, HDL cholesterol, and triglycerides were determined enzymatically. In addition, the antioxidant activity of plasma was estimated by using the TEAC and the TRAP assays. RESULTS: The basal levels of lycopene in plasma were comparable for all groups (0.2-0.3 mumol/l) and decreased significantly during the two weeks of depletion to approximately 50% of the basal values. Other plasma carotenoids such as beta-carotene and beta-cryptoxanthin decreased significantly, too, whereas lutein and zeaxanthin remained unchanged. After supplementation with tomato oleoresin capsules or tomato juice, the plasma lycopene increased significantly, while it remained unchanged during intake of tomatoes. Normal dietary habits were practised of all volunteers before and during the study except vitamin C whose intake was significantly lower during the study period, because the probands were recommended to reduce the intake of fruits and vegetables. Lycopene supplementation did not affect the lipid status parameters of the three groups. After ingestion of lycopene the antioxidant activity of the plasma was not altered. Mean TEAC values were estimated to 0.33 +/- 0.05 mmol/l and TRAP values to 1.0 +/- 0.1 mmol/l and showed no significant differences in all groups during the whole study period. CONCLUSIONS: The bioavailability of lycopene varied significantly depending on the administered matrix. Lycopene from tomato oleoresin capsules and tomato juice (processed tomatoes) was better absorbed from the intestine than lycopene from raw tomatoes. The daily intake of 5 mg lycopene, an intake comparable to the usual daily carotenoid intake, did not affect cholesterol and triglycerides in plasma or its antioxidant capacity.

Adult↗
PubMed1999

Alteration of thiamine pharmacokinetics by end-stage renal disease (ESRD).

OBJECTIVE: In a comparative study with 20 end-stage renal disease (ESRD) patients the pharmacokinetics of two therapeutically used thiamine (vitamin B1) preparations were assessed. SUBJECTS, MATERIAL AND METHODS: After a single oral dose of either 100 mg benfotiamin (S-benzoylthiamine-o-monophosphate, BTMP) or 100 mg thiamine mononitrate (TN), blood levels of thiamine phosphate esters were analyzed by HPLC after precolumn derivatization to thiochrome phosphate esters for a 24-hour period. RESULTS: The pharmacokinetic parameters AUC0-24h, Cmax and tmax of the benfotiamin group in whole blood and plasma exceeded significantly those in the TN group. Only 1.0 vs. 0.6% of the administered dose were excreted in urine in the BTMP group and TN group, respectively. A high cellular efficacy, as was concluded from the short-term stimulation of the thiamine-dependent transketolase activity in erythrocytes (ETKA), was assessed for BTMP as well as TN. The activation coefficient (ETK-AC) decreased significantly from 1.10 to 1.04 vs. 1.12 to 1.07 in both the BTMP as well as TN groups, respectively. In addition, a high transfer rate to thiamine diphosphate (TDP) was observed in the patients after ingestion of BTMP. The TDP concentration in whole blood increased by 2.6 and 1.4 times from baseline levels to Cmax in the BTMP and TN groups, respectively. The AUC0-24h of TDP in whole blood after BTMP ingestion exceeded those after TN ingestion by 420%. CONCLUSION: These findings justify the therapeutic application of BTMP in ESRD, because a high intracellular concentration of TDP may protect against numerous adverse effects of uremia in the long run.

Chromatography, High Pressure Liquid↗
PubMed1998

Are patients with chronic renal failure (CRF) deficient in Biotin and is regular Biotin supplementation required?

In 23 patients with chronic renal failure (CRF), 23 patients on chronic intermittent hemodialysis treatment (DP), 22 patients after renal transplantation (RT) and 40 normal persons (NP), Biotin plasma levels and the urinary excretion were analysed and compared to the dietary Biotin intake. Unsupplemented DP had lower intake of Biotin than the CRF, RT, NP and DP with supplementation. DP excreted only 1.6-6.3% of the daily intake as compared to 39.7% in NP, 27.6% in CRF and 24.3% in RT. In unsupplemented DP patients, Biotin plasma levels were elevated by 4 times and in supplemented patients by 6 times compared to NP. During hemodialysis treatment, the Biotin plasma level dropped by about 30% in DP with and by 33% in DP without vitamine supplementation. However, after 44 hours, the initial concentration was reached again in those receiving vitamine supplementation (99% of basal level) and in DP without substitution (97% of basal level). Only in male DP significantly higher Biotin plasma levels before HD were detected irrespective of the supplementation dose as compared to female patients (30 micrograms and 300 micrograms Biotin after each dialysis session). Biotin plasma concentration did not vary with respect to the underlying renal disease, the serum creatinine concentration and the length and frequency of dialysis treatment, including the type of dialyzer (low- vs high flux) used and the blood flow rate (QB 180-260 vs 270-280 vs 300 ml/min). There were no major effects of the age of the patients (< 60 years vs > 60 years), the BMI, nicotine abuse, or alcohol intake on Biotin blood concentration. Our results showed normal Biotin plasma levels which reflect a normal functional status and exclude a functional deficit, therefore there is no reason for a regular Biotin supplementation in patients with chronic renal failure.

Age Factors↗
PubMed1998

Comparative bioavailability of various thiamine derivatives after oral administration.

In a multiple change-over study the bioequivalence of 3 thiamine preparations, used therapeutically as neurotropic agents for the treatment of polyneuropathies, was tested in a collective of 7 volunteers. After ingestion of a single dose of either 100 mg benfotiamin CS-benzoylthiamine-o-monophosphate), fursultiamin (thiamintetrahydrofurfuryldisulfide) or thiaminedisulfide, thiamine blood levels were analyzed for a 10-hour period. Thiamine was measured by HPLC after precolumn derivatization to thiochrome. The maximal thiamine concentration Cmax and its time (tmax) in plasma and hemolysate, the area under concentration time curve (AUC), and thiamine excretion in 24-hour urine were assessed as criteria of bioavailability. Additionally the erythrocytic transketolase activity (ETK) and alphaETK were determined as indicators of the cellular thiamine availability. After benfotiamin ingestion a more rapid and earlier increase of thiamine in plasma and hemolysate was observed in contrast to fursultiamin and the disulfide. All biokinetic data demonstrated a significantly improved thiamine bioavailability from benfotiamin compared with the other preparations. The lowest bioavailability was detected with thiamindisulfide. From our results it can be concluded that oral administration of benfotiamin is best suitable for therapeutical purposes owing to its excellent absorption characteristics.

Administration, Oral↗
PubMed1997

[Vitamin B1, B2, A and E and beta-carotene content in transitional breast milk and comparative studies in maternal and umbilical cord blood].

The contents of the vitamins B1 (27 ng/ml), B2 (57 ng/ml), A (1.3 micrograms/ml), and E (9.7 micrograms/ml) as well as beta-carotene (0.2 microgram/ml) in transitional human milk were determined for up to 35 women aged between 19 and 31 years. Additionally, the vitamin content in maternal and cord plasma as well as the erythrocytic transketolase- and glutathione-reductase activities of the water soluble vitamins were measured. Dietary recalls were evaluated for the nutritional intake of vitamins. Concerning the fat soluble vitamins, the breast fed newborns received the recommended amounts of the German Society of Nutrition (DGE) for this group. In contrast to this, the supply of the water soluble vitamins (B1: 13.5 micrograms/500 ml; B2: 28.5 micrograms/500 ml) attained only 5 to 10% of the recommendations for newborns during the first two weeks after parturition with breast feeding. Vitamin content of maternal plasma (B1: 6.1 +/- 2.8 ng/ml) and erythrocytic enzyme activities (alpha ETK: 0.86-1.62; alpha EGR: 1.08-1.75) indicated a low or sufficient intake, while the values in cord blood (B1: 19.8 +/- 6.5 ng/ml; alpha ETK: 0.62-1.62; alpha EGR: 1.01-1.47) were in accordance with a satisfactory supply.

Adult↗
PubMed1997

Vitamin C status of patients with chronic renal failure, dialysis patients and patients after renal transplantation.

The vitamin C status of patients with chronic renal failure (CRF), dialysis patients (DP) and patients after renal transplantation (RT) was the object of this investigation. Levels of vitamin C intake from dietary records were estimated at mean values of 93.5 mg/d (CRF), 65.5 mg/d (DP) and 163.9 mg/d (RT). Compared to the recommendation of the German Society of Nutrition (75 mg/d), this indicated a normal range of supply for all groups except the group of DP. The corresponding mean plasma concentrations were 62.2 mumol/l (CRF), 80.3 mumol/l (DP) and 68.8 mumol/l (RT). Supplements of 60 or 100 mg vitamin C given to patients of the DP-group after each dialysis session showed slightly, but not significantly higher concentrations of vitamin C in plasma. During dialysis treatment, plasma vitamin C concentrations dropped to approximately 50% of the basal value, but almost reached initial levels again 44 hours later, both with and without supplementation. During one treatment period, vitamin C loss in the dialysate of three patients ranged between 92.5 and 333.6 mg. The amount of vitamin C in plasma, however, dropped to approximately 50% of the basal value for these patients, too.

Adult↗
PubMed1993

Vitamin B6.

Explore the source record for details and available documents.

Humans↗
PubMed1991

Bioavailability assessment of the lipophilic benfotiamine as compared to a water-soluble thiamin derivative.

The bioequivalence of thiamin in 2 therapeutically used preparations was tested in 10 healthy young men. Thiamin was orally administered either as lipophilic benfotiamine or as water-soluble thiamin mononitrate. Biokinetic data, measured as area under the curve and maximal concentration in plasma and hemolysate after ingestion, demonstrated a significantly improved bioavailability from the lipophilic derivative despite an ingested dose of only 40% as compared with the water-soluble salt. A superior cellular efficacy of benfotiamine was also concluded from the short-term stimulation of the thiamin-dependent transketolase activity in erythrocytes.

Adult↗
PubMed1989

Biotin assessment in foods and body fluids by a protein binding assay (PBA).

The biotin content of plant and animal food samples as well as of human plasma and urine specimens was assessed by a modified protein binding assay (PBA). Protein bound biotin in samples was released by digestion with papain, food samples were in addition treated previously with liquid nitrogen. Comparing analyses by use of the conventional microbiological test with L. plantarum resulted in slightly enhanced biotin values, in case of plasma by 9.2% and in case of urine by 10.3%, but the results obtained by both methods correlated well (r = 0.926 for plasma and 0.934 for urine). Regarding food analysis the additional comparison of different disintegration procedures led to best reproducible results by using the PBA with preceding papain digestion.

Adult↗
PubMed1989

Studies on bioavailability of oral biotin doses for humans.

Single biotin doses (600 micrograms and 900 micrograms) orally administered to male and female volunteers were very rapidly eliminated from plasma after absorption leading to a remarkable increase of urinary excretion. A prolonged enhancement of plasma levels occurred only after continuous supplementation with 300 micrograms biotin/day for 1 week and following 900 micrograms biotin/day for another week. From the diurnal turnover of the plasma level after oral stimulation with 600 micrograms biotin some biokinetic indices, such as the constants of invasion and elimination rate as well as the elimination half life time were determined. The median of the invasion constant was calculated to 2.068 h-1, that one of elimination constant to 0.3867 h-1 suggesting no indication of diminished body stores. The elimination half life time of the administered biotin dose from plasma amounted to 1 hour, 50 minutes.

Administration, Oral↗