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Biomedical subjects

D Hötzel

Publications and source records attributed to D Hötzel.

At least 19 recordsLinked to original sources
PubMed1995

[Determination of intestinal strontium absorption--assessment and validation of routinely manageable test procedures].

Intestinal strontium absorption has been discussed recently as an indirect measure for calcium uptake. Prerequisite for the clinical use of an oral strontium test is the availability of a reliable procedure including controlled strontium supply, sample pretreatment and analysis as well as the assessment of normal values. In the present study, a group of young females (n = 33; 24.0 +/- 2.7 y; BMI 21.5 +/- 1.9) received an oral dose of 2.27 mmol strontium in a standardized breakfast that contained 0.625 mmol calcium. Before and 220 min after the bolus serum strontium concentrations were determined by means of atomic absorption spectrophotometry (coefficient of variation: within day 4.8%, n = 10; day-to-day 9.5%, n = 8). The error of the method was 2.7%. Calculation of the fractional strontium absorption rate considered the respective distribution volume (extracellular fluid; either estimated using body weight or determined by means of bioimpedance analysis [BIA]). Average absorption rates were 13.3 +/- 3.1% and, considering BIA measurement 13.6 +/- 2.6%, respectively. Smoking, exercise and, use of oral contraceptives showed no effects. Our oral strontium test is characterized by excellent reliability, easy handling and low costs and, thus, is suitable for routine use.

Administration, Oral↗
PubMed1991

[Nutrition and primary osteoporosis].

Osteoporosis is a bone disease of great sociomedical and economic importance. Postmenopausal women are primarily affected. Pathogenesis is of multifactorial origin. In Western countries, reduced physical activity and an inadequate nutritional calcium supply are important aspects besides decreased postmenopausal oestrogen secretion. Food statistics confirm that in the Federal Republic of Germany calcium intake is below the DGE recommendation in almost all age groups, especially in women. Calcium may play a role in prevention of osteoporosis. The paper reports on individual measures to enhance calcium intake. Furthermore, the influence of the postmenopausal status on calcium metabolism and calcium requirement is demonstrated. Finally, the importance of other nutritional aspects for the manifestation of osteoporosis is discussed.

Calcium, Dietary↗
PubMed1990

Cadmium, copper, lead, and zinc concentrations in human scalp and pubic hair.

Cadmium, Cu, Pb, and Zn concentrations were measured in the first 3 cm of the proximal end of scalp hair and in pubic hair of 41 humans, by atomic absorption spectrometry. Data are presented as geometric means. Scalp hair (SH) metal levels were higher than those in pubic hair (PH), (Cd, 85.1 vs 60.8 ng g-1; Cu, 17.7 vs 11.9 micrograms g-1; Pb, 1.72 vs 1.05 micrograms g-1; Zn, 148.8 vs 133.3 micrograms g-1) with correlation coefficients of: Cd, r = 0.474; Cu, r = 0.549; Pb, r = 0.576; and Zn, r = 0.263. Further correlations were established between Cd and Pb levels (SH, r = 0.691; PH, r = 0.621) as well as between Cd and Zn levels (SH, r = -0.268). In PH the Cd, Cu, and Pb levels of males were higher than those of females, whereas the Zn levels were lower in SH and PH of males. Scalp hair Zn contents were inversely related to age. Cadmium and Pb levels in SH and PH were higher in summer than in winter, whereas the SH Zn contents were higher in winter. An influence of place of residence, smoking habit, hair colour and hair structure on SH and PH metal levels is identified. It is concluded that hair metal analysis in samples close to the scalp is not seriously invalidated by sources of external contamination.

Adolescent↗
PubMed1990

[The evaluation of "natural" sweeteners, especially concentrated fruit juices, syrups and honey].

The present paper deals with the nutritional value of some natural sweeteners, like concentrated fruit juices, special syrups and honey. The following aspects are discussed: concentration of sweet-tasting carbohydrates, average composition of essential nutrients like minerals and vitamins, and occurrence of other substances like organic acids etc. The nutritional value of natural sweeteners is not significantly different from "sugar" (saccharose): Natural sweeteners do not contribute to fulfill the need for minerals, trace elements or vitamins in an important manner. The sensoric properties are different and the intensity of sweet-taste is usually higher in sucrose than in syrups. Descriptions of such products as "naturally", "healthy", "without sugar" are not justified.

Carbohydrates↗
PubMed1989

[The contribution of nutrition to the pathogenesis of osteoporosis].

Osteoporosis primarily affects women and is a bone disease of great social, medical and economic importance. The pathogenesis is thought to be of multifactorial origin. The current work discusses nutritional aspects relative to osteoporosis. In this aspect, calcium supply seems to have the largest preventional importance. In contrast, food statistics and individual food records show that calcium intake of females is below the DGE's recommendation of 800 mg/daily. Furthermore, in view of skeletal integrity, calcium intake should be increased up to 1,500 mg/daily after menopause, because of endocrinological changes in calcium metabolism. Therefore, calcium intake on the whole is usually found to not be sufficient. The importance of further nutritional aspects for manifestation of osteoporosis are discussed. In some cases, influences on skeletal integrity are quite evident, whereas the literature has only infrequently drawn conclusions about the pathogenesis of osteoporosis.

Calcium↗
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↗
PubMed1983

[Methods and their evaluation for the estimation of vitamin B6 levels in man. 5. Serum pyridoxal-5-phosphate determination: method and comparison of methods].

Methods and Their Evaluation to Estimate the Vitamin B6-Status in Human Subjects. V. S-PLP-Determination: Method and Comparison of Methods. A method to determine the plasma pyridoxal 5-phosphate (PLP) basing on the enzymatic decarboxylation of 1-14C-l-tyrosine and the measurement of the radio-active 14CO2 is described. Its efficiency is discussed in comparison with other methods. High specificity, precision, accuracy, and sensitivity are demonstrated. The developed equipment allows to analyse a great number of samples and minimizes the risk of radio-active contamination. The commercial apoenzyme preparations are different in quality and require purification. Apoenzyme lots with high genuine content of PLP are useless. Storage tests at 4 degrees C, -18 degrees C, and -196 degrees C show stability of the samples for one day, 30 days, and at least 10 weeks.

Carbon Radioisotopes↗
PubMed1982

Thiamin Metabolism in the rat during long-term alcohol administration. 1. Communication: ethanol induced changes at optimal thiamin supply.

The effect of ethanol administration on the phosphorylation of thiamin, and on the transketolase activity (TKA) in erythrocytes, heart and liver, and on the thiamin excretion in urine was investigated in rats optimally supplied with thiamin over a period of 16 weeks. Ethanol ingestion resulted in a diminished concentration of thiamin (T), thiaminmonophosphate (TMP), thiamindiphosphate (TDP) and thiamintriphosphate (TTP) in blood and organs and in a reduced excretion rate of T in urine due to an impaired intestinal absorption. An ethanol induced alteration of the degree of thiamin phosphorylation became evident only after 16 weeks resulting in a decline of T and TMP in blood and of T in heart to undetectable amounts and in an enhancement of the TDP- and TTP-pool. Despite an increasing content of TDP in erythrocytes the TKA was lowered and the alpha-TK was enhanced during the test period suggesting a partially inhibited formation of the active holoenzyme by alcohol in vivo. However, the lowered TKA and the normal alpha-TK in liver are primarily suggestive of an apo-enzyme degeneration influenced by ethanol.

Alcoholism↗
PubMed1982

[Methods and their evaluation in the determination of vitamin B6 status in man. 2. alpha-SGOT: reliability of the parameter].

Some factors, which are primary independent of the vitamin B6-uptake have influence on the maximum and/or the basis activity of the EGOT and thereby finally on the alpha-value. There is a negative correlation between the age of the test persons and both the maximum and the basis activity. An insufficient supply with protein leads to lowered maximum activities, but we could not estimate a correlation between EGOT+ and protein-intake when adequate. Influences of oral contraceptives as well an enzyme induction caused by long-term high vitamin B6-uptake can not confidently be excluded. Specific differences between the enzyme activities of men and women are scarcely probable. EGOT+ and EGOT- are lowered by chronic alcohol abuse. A short-term load with alcohol does not change the results. Oral contraceptives as well as the vitamin B2 status have little if any influence on the enzyme activities. Our results show, that because of the various possible influences a single determination of the alpha-value is a doubtfull parameter to assess the vitamin B6 status of men. Only the observation of the alteration of the individual alpha-value during deficiency and substitution tests, considering at the same time some essential incidentals, can lead to well-founded statements.

Adult↗
PubMed1982

Thiamin metabolism in the rat during long term alcohol administration.

In order to test the effect of a long term alcohol administration on the thiamin metabolism in blood, heart and liver under suboptimal supply, an experiment with rats was carried out over a period of 16 weeks. The suboptimal thiamin supply became visible mainly in the liver stores which were lowered during the whole test period. The unphosphorylated thiamin (T) of liver and heart was not detectable after 4 weeks up to the end of experiment. On the other hand the total thiamin concentration in the erythrocytes increased from the beginning due to an enhanced thiamin-diphosphate (TDP) and thiamintriphosphate (TTP) pool and T was lowered to undetectable amounts only after 16 weeks. In contrast, the alpha-TK in blood and liver was enhanced only after 2 and 4 weeks and tended to become normal by the end of the test period indicating an apoenzyme degeneration. Alcohol ingestion resulted in a general diminution of the total thiamin and the thiamin phosphates in blood, heart and liver and a reduced thiamin excretion in urine. An alcohol induced shift of the phosphorylation status could be observed only in the liver, but not in the heart and the erythrocytes, leading to a lowered concentration of T and TMP. The results demonstrate that the level of thiamin and thiamin phosphates in blood and organs under suboptimal thiamin supply seems to be more sensitive to chronic alcohol administration than the transketolase activity and the alpha-TK value.

Animals↗
PubMed1982

[Methods and their evaluation in estimating the vitamin B6-status in humans. 3. Determination- of 4-pyridoxic acid in urine].

A method based on the fluorimetric determination of the 4-PA-lactone is described. The applied method saves time and work compared to others. The analytical procedure may be interrupted for a few days after eluting the 4-PA from the ion exchanger as well as before measuring the transmission. Accuracy, precision and sensitivity of the method are demonstrated. Interfering substances influencing the fluorescence measurement and probable errors caused by the reference value creatinine are discussed. Storage tests applied with the urine samples at--18 degrees C have shown that 4-PA-values do not change considerably within two months.

Chromatography, Ion Exchange↗