Biomedical subjects

G Schöch

Publications and source records attributed to G Schöch.

At least 19 recordsLinked to original sources

PubMed2000

A high-performance liquid chromatographic method for the determination of 8-oxo-7,8-dihydro-2'-deoxyguanosine in urine from man and rat.

The renally excreted amount of 8-oxo-7,8-dihydro-2'-deoxyguanosine (oxo(8)dG) is a potential marker of oxidative DNA damage by reactive oxygen species. We have developed a high-performance liquid chromatographic (HPLC) method to determine oxo(8)dG in urine from humans and Wistar rats. First, 300 microl of filtered urine is prefractionated by solid phase extraction (BAKERBOND SPE C(18) Polar Plus column). Then, the HPLC separation of the fraction containing oxo(8)dG is performed using four HPLC columns (two cation exchange and two C(18) columns) in series with an automated column switching technique. Quantification of oxo(8)dG is performed by electrochemical detection (Coulochem II, ESA Inc.). Limit of detection was 0.4 nM oxo(8)dG. Recovery of oxo(8)dG added respectively in 11 or 8 concentration steps (range, 4-74 or 2-23 nM) to a pooled human or rat urine was 104.1 +/- 4.3 or 104.5 +/- 7.7%. Precision of sixfold analysis of a pooled human or rat urine carried out respectively on the same day was 2.2 or 2.4% relative standard deviation. Normal excretion rates of oxo(8)dG in healthy adult humans (five females, six males; body weight, 70.7 +/- 11 kg) and male Wistar rats (body weight, 309 +/- 13 g) were 281.7 +/- 179.1 and 333.2 +/- 47.4 pmol oxo(8)dG/day/kg weight, respectively.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2000

Renal excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine in Wistar rats with increased O(2) consumption due to cold stress.

DNA damage by reactive oxygen species is of special interest in the development of cancer and in aging. The renally excreted amount of 8-oxo-7,8-dihydro-2'-deoxyguanosine (oxo(8)dG) is a potential noninvasive marker of oxidative DNA damage. The respiratory chain of mitochondria is one source for the formation of reactive oxygen species. In the present study we investigated in Wistar rats (n = 7; mean body weight at start, 307.4 +/- 11 g) the effect of an increased O(2) consumption, i.e., energy expenditure, due to cold stress on the renally excreted amount of oxo(8)dG. First, the rats were housed for 4 days at 23.5 degrees C (basic period, BP), and then for 6 days at 10 degrees C (cold stress period, CSP), and finally for 3 days at 23.5 degrees C (recovery period, RP). The O(2) consumption (L O(2)/day/kg weight) was significantly (P < 0.0001) on average 50% higher in CSP (69.0 +/- 3.9) than in BP (45.8 +/- 4.8), and similar in BP and RP (44.3 +/- 5.4). The average renal excretion of oxo(8)dG (pmol/day/kg weight) was significantly (P < 0.025) on average 13% higher in CSP (375.5 +/- 27.7) than in BP (333.2 +/- 47. 4) and similar in BP and RP (331.8 +/- 34.3). Maximum increase in oxo(8)dG excretion of on average 17% was on the third to fifth day of the CSP. This study reveals that an increase in O(2) consumption of 50% resulted in a much lower increase in the renal excretion of oxo(8)dG.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2000

Whole-body degradation rates of transfer-, ribosomal-, and messenger ribonucleic acids and resting metabolic rate in 3- to 18-year-old humans.

Whole-body degradation rates of transfer, ribosomal, and messenger RNA were determined noninvasively in 3-, 6-, 10-, 14-, and 18-y-old female and male subjects (n = 14 per age group per sex) under normal living conditions. The method for determining the RNA degradation rates is based on measuring the renal excretion rates of special RNA catabolites (modified ribonucleosides and nucleobases) by HPLC. Resting metabolic rates were calculated for the same subjects by their body weights using formulas taken from literature. We found high correlations between the degradation rates of the different RNA classes (micromoles per day per kilogram body weight) and the resting metabolic rate (kilojoules per day per kilogram body weight): in females (n = 70), r = 0.75-0.82 and in males (n = 70), r = 0.68-0.79 (p<0.0001). We conclude that a causal relationship exists between the whole-body degradation rates of the different RNA classes and the resting metabolic rate. Therefore, in healthy subjects noninvasive determinations of RNA degradation rates could be very useful to assess the resting metabolic rate.

Adolescent↗

PubMed1999

Development of scores to measure the effects of nutrition counselling on the overall diet: A pilot study in children and adolescents.

An intervention study by documented dietary counselling was carried out in a sample of 9 children and adolescents (12-15 years) living in a full-time institution in Dortmund. Three weighed dietary records were collected over 3-7 days, one before and one after each of two individual nutrition counselling sessions, which were based on the recommended intake of food groups defined by the Optimized Mixed Diet (OMD), a quantitative preventive dietary conception for children and adolescents. As univariate dietary parameters (e.g., cholesterol intake), which are often used to show the effectiveness of nutrition counselling, do not take into account the multivariate complexitiy of nutrition, we developed 3 multivariate scores to measure the effectiveness of nutrition counselling. They are defined as: Recommended Food group change Score (RFS): Average change in the amounts of the deviations (%) from the reference food groups values (OMD = 100 %) before and after counselling taking into account the aim (eat mor/less) of the counselling session, exclusively based on the food groups addressed during counselling. Total Food group change Score (TFS): Average change in the amounts of the deviations (%) from the reference food group values (OMD = 100 %) before and after counselling based on all food groups consumed. Nutrient Improvement Score (NIS): Average change in the negative deviations (%) of 8 vitamins and 8 minerals from the German reference values for nutrient intake (Deutsche Gesellschaft für Ernährung (DGE) = 100 %) before and after counselling. On average, the intakes of the food groups mentioned during the first counselling session improved considerably (RFS = +36 %), the change in the intake of all food groups was small (TFS = +6 %) and the nutrient intakes did not improve (NIS = 0 %). From the second counselling session the values of the RFS was +10 %, of the TFS was +6% and of the NIS +3 %. This means that the success of counselling on one dietary criterion does not guarantee success on others. Our food and nutrient based scores together with a detailed food intake assessment give an example of multivariate measurements of nutrition counselling outcomes.

Adolescent↗

PubMed1999

Vitamin intake of 3- to 36-month-old German infants and children--results of the DONALD-Study.

Infants and young children are a vulnerable group with regard to nutrition. However, there is a lack of information about the dietary composition of healthy German infants and children. Therefore, the intake of vitamins (A, C, E, B1, B2, B6, folate, niacin) was assessed in 354 healthy German infants and children aged 3 to 36 months from 3-day-weighed diet records and compared with German, European and US reference values. Intake of all B-vitamins (B1, B2, B6, folate, niacin) increased during the first 3 years of life, whereas intake of vitamin E decreased. Intake of vitamin A and C varied between age groups. The highest levels of the nutrient densities of most vitamins were found at the end of the first year of life. Depending on the reference values chosen, the vitamin supply of the study population ranged between sufficient and very good. The reported satisfactory intake of vitamins in infants and young children in this study gives rise to the question of whether the current extent of fortification of commercial infant food in Germany is necessary.

Breast Feeding↗

PubMed1999

Consumption of fortified food between 1985 and 1996 in 2- to 14-year-old German children and adolescents.

Since the 1980s, fortified food plays an increasing role in food marketing in Germany. However, there is a lack of data concerning fortified food consumption. We therefore evaluated dietary information of the DONALD Study. A total of 2251 3-days weighed records between 1986 and 1996 from 637 different subjects aged between 2 and 14 years (mean: 6.6 years) were evaluated. Food products were defined as fortified if enriched at least with one of the following nutrients: vitamin A (including provitamin A carotenoids), E, B1, B2, B6, C, niacin, folate, calcium, magnesium, potassium, iron or phosphate. Products were grouped in 'Diary products', 'Cereals', 'Beverages', 'Instant Beverages', 'Sweets/biscuits', 'Fats/oils', and 'Beikost' (i.e. dietetic food intended for infants and young children under 4 years). Over the last 11 years almost all children and adolescents consumed fortified food products. Excluding the food group 'Fats/oils' the proportion of consumers of fortified food increased by about 20% between 1986 and 1996. During the same period the consumption rate increased up to five-fold for the food group 'Beverages' and fourfold for 'Cereals'. Since 1988, a relatively constant consumption ratio of 62-68 different fortified products per 100 consumers has been found. 'Beverages' showed the highest food-group-specific diversity. In Germany, vitamins are more often used than minerals to fortify food, whereas vitamin C is the most frequent added nutrient. We found some interesting time trends in the use of vitamins and minerals for fortification with a continuous increase in the use of vitamin C and E. Only vitamin A showed a decrease in use during the study period. Finally, we found a decreasing number of consumers of all fortified products at the end of the study period.

Adolescent↗

PubMed1999

Fruit juice consumption and the prevalence of obesity and short stature in german preschool children: results of the DONALD Study. Dortmund Nutritional and Anthropometrical Longitudinally Designed.

BACKGROUND: In recent years, a possible association between excessive consumption of fruit juice (> or =12 fl oz per day) and short stature and/or obesity has been discussed. The association among the consumption of fruit juice, anthropometric indices, and the overall diet was examined during a 3-year period in a sample of healthy preschool children participating in the Dortmund Nutritional and Anthropometrical Longitudinally Designed (DONALD) Study. METHODS: Two hundred five children were examined annually at the ages of 3, 4, and 5 years. Dietary intake was calculated from 3-day weighed diet records. Height was measured using a stadiometer. Weight was measured using an electronic scale. RESULTS: Five children consumed excessive fruit juice continually in all three records, 10 children in two records, and 23 children in one record. None of the five children with repeatedly excessive fruit juice consumption was obese or short. Growth velocity, body mass index, and height standard deviation score were not correlated with fruit juice consumption. Consumption of fruit juice was inversely correlated with the consumption of all other beverages and the total consumption of all other food. The intake of protein, fat, and carbohydrates of children consuming excessive fruit juice was closer to the international dietary preventive guidelines than the intake of children consuming low amounts of fruit juice. CONCLUSIONS: In the study sample, even repeatedly excessive fruit juice consumption had no influence on anthropometric indices. The results do not justify a general warning or a general promotion regarding high fruit juice consumption in preschool children's diets.

Animals↗

PubMed1999

Macronutrient intake of 3- to 36-month-old German infants and children: results of the DONALD Study. Dortmund Nutritional and Anthropometric Longitudinally Designed Study.

The intake of macronutrients (protein, fat, fatty acids, carbohydrates, added sugars, fiber) was assessed in 354 healthy German infants and children aged 3-36 months from 3-day weighed diet records. The intake of protein ranged between 7 and 14% of energy intake. Fat intake decreased from 3 months (breast-fed boys and girls, 48%; formula-fed boys/girls, 41/44%) to 12 months (boys/girls, 33/36%) due to the increasing consumption of commercial weaning foods, and then increased again up to 36 months (boys/girls, 40/43%). Intake of added sugars decreased during the first 12 months and then increased again, but only slightly exceeded the limit of 10%. Intake of dietary fiber was highest at the age of 1 year (boys/girls, 2.7/2.3 g/MJ). The macronutrient intake was in accordance with other German and European surveys, but deviated considerably from the respective recommendations.

Age Factors↗

PubMed1998

Renal excretion of gamma-carboxyglutamic acid and metabolic rate in 3-18 years old humans.

The modified amino acid gamma-carboxyglutamic acid (Gla) occurs in several proteins such as prothrombin, blood coagulation factors VII, IX and X, proteins C, S and Z as well as matrix Gla protein and osteocalcin. The amount of Gla excreted in urine is a common indicator of the whole-body degradation of these proteins. We have determined the renal excretion rates of Gla in 3, 6, 10, 14 and 18 years old male and female human subjects (n = 14 per age group and sex) and calculated the respective resting metabolic rates (RMR) on the basis of the body weights using published formulas. We found high correlations between the excretion rates of Gla (mumol/d/kg body weight) and the RMR (kJ/d/kg body weight) in the females (n = 70) of r = 0.70 (y = 0.003x + 0.29) and in the males (n = 70) of r = 0.70 (y = 0.0038x + 0.27) and in all subjects (n = 140) of r = 0.69 (y = 0.0035x + 0.27); p < 0.01. We postulate that in children and adolescents a causal relationship exists between the whole-body degradation rate of Gla containing proteins and the metabolic rate.

1-Carboxyglutamic Acid↗

PubMed1998

Energy intake of 1 to 18 year old German children and adolescents.

In a sample of 695 healthy well-nourished German children and adolescents covering the total age range from 1 to 18 years, 3d weighed diet records were collected and measurements of body height and weight were taken. 10% non-plausible records (reported energy intake (EI):estimated basal metabolic rate (BMR) < Cut off 1.06) were excluded from further analysis. The rate of non-plausible records was low in the childhood age groups (2-6%), higher in the male (10%), and highest in the female adolescents (30%). Recalculation of age and sex specific cut offs based on assumed light physical activity levels (PAL) reduced the exclusion rate to 6.5% (total) and 20% (female adolescents). The reported energy intake of the total sample based on plausible records (n = 627, EI:BMR > or = 1.06) was close to the new estimations of energy requirements assuming light physical activity which are proposed for the revision of the current FAO/WHO energy requirements. The sample was of normal height and weight compared to the Netherlands growth references. For a definite interpretation of the low reported energy intake in the context of health promoting physical activity patterns of children and adolescents more scientific evidence should be available.

Adolescent↗

PubMed1998

Expiration of ethane in rats under variously elevated inspiratory O2-concentrations.

Expired ethane is regarded as a noninvasive indicator of lipid peroxidation. As a model of oxidative stress we have investigated in male Wistar rats (body wt. 309 +/- 15 g) the effects of various levels of elevated inspiratory oxygen concentrations on the expiration rate of ethane. After 4 days under 21 vol% O2 (basic condition) the rats were exposed for 6 or 5 days to 40, 60 or 80 vol% O2 over 8 or 23 h/day. The variously O2-enriched air was conducted through the cages and expired ethane adsorbed onto charcoal was thermo-desorbed and measured by gas chromatography. Basic ethane expiration was 3.1 +/- 0.8 pmol/100 g body wt. per min. At 40 vol% O2 over 8 or 23 h/day no increase or a maximum average 47% increase (P < 0.01) in ethane expiration occurred on day 4; 60 vol% O2 over 8 or 23 h/day led to a corresponding increase of 56 or 87% (P < 0.05 or P < 0.01) on day 3; 80 vol% O2 over 8 or 23 h/day led to a corresponding increase of 81 or 66% (P < 0.01) on days 3 or 2. Our results indicate that with up to 60 vol% O2 a temporary increase in lipid peroxidation occurs in a dose dependent manner. However, at 80 vol% O2 no further increase in the maximum ethane expiration occurred. The latter finding and the finding of only transient increase in ethane expiration in probably due to antioxidative counteraction.

Animals↗

PubMed1998

Induction of single-strand breaks in lymphocyte DNA of rats exposed to hyperoxia.

A modified technique of alkaline filter elution was used to evaluate single-strand breaks (SSB) as a measure of DNA lesions in lymphocytes of male Wistar rats exposed to 60 or 80 vol% oxygen, over 23 h/day and for 6 or 5 days, respectively. An acceleration of elution was observed with samples from experiments at both increased levels of oxygen. With proteinase K treatment, a twofold increase in elution rates after exposure to 60 vol% oxygen and a threefold increase at 80 vol% oxygen were indicative of increased occurrence of SSB. This is explained by an involvement of reactive oxygen species in DNA damage under elevated oxygen levels.

Animals↗

PubMed1998

Underreporting of energy intake in 1 to 18 year old German children and adolescents.

It is generally accepted that self-reported food intakes underestimate habitual energy intake (underreporting). Underreporting is often addressed by computing the ratio of measured energy intake to predicted basal metabolic rate (EI:BMR). We used this ratio to study differences between not plausible records (NPR) and plausible records (PR) according to recalculated cut-off values for EI:BMR ratios (< 0.97 to 1.07; age- and sex-dependent) in cross-sectional data of 1,032 3d weighed diet records of 1 to 18 year old children and adolescents. Underreporting (in 5% of total subjects) was age and sex dependent: about 1% in the 1 to 5 year old children, 2% (3%) in the 6 to 13 year old males (females) and 12% (20%) in the adolescent males (females), respectively. To analyse differences between subgroups with PR vs. NPR we therefore concentrated on the 14 to 18 year olds. Male (female) subjects with NPR vs. PR had a 40% lower total EI: 7.4 MJ/d (5.3 MJ/d) vs. 11.5 MJ/d (8.0 MJ/d), respectively. In both sexes with NPR vs. PR, EI per meal was lower. Females with NPR vs. PR had a higher body mass index (kg:m2), recorded fewer meals per day, and had a shorter time span between the first and last meal per day. Furthermore, females with NPR vs. PR had higher intakes per MJ of water, protein, fiber, sodium, iron, niacin, zinc, and protein in percent of total EI, but a lower intake of added sugars per MJ. Males with NPR vs. PR answered significantly more often that they usually eat more, had a higher water intake per MJ, and a higher Ca:P. The observed differences between groups with PR and NPR indicate different food habits or dietary recording behavior. Therefore, validity in dietary studies cannot be achieved by simply excluding underreporters.

Adolescent↗

PubMed1998

Macronutrient intake of 1 to 18 year old German children and adolescents.

In a sample of 627 healthy German children and adolescents between the age of 1 and 18 years the intake of macronutrients (protein, fat, carbohydrates) and their specific subgroups (animal protein, saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), cholesterol, added sugars, dietary fiber) were assessed from 3d weighed diet records. The medians of the nutrient intake (% of energy) were 13% protein (2/3 animal), 38% fat, 49% carbohydrates, 17% SFA, 16% MUFA, 5% PUFA, 12% added sugars and (per MJ) 34 mg cholesterol, 1.9 g dietary fiber. The macronutrient patterns were almost uniform across the age and sex groups with the exception of lower fat, PUFA, and sugar intakes in the 1 year olds. The findings were almost in accordance with former and current dietary surveys in Germany and neighboring countries. Several findings, particularly the high SFA and low fiber intake, differed considerably from the diet for the prevention of the chronic diseases related to nutrition in western societies which is recommended for this age range. Based on the findings of this study, a preventive dietary concept for German children and adolescents was proposed.

Adolescent↗

PubMed1998

The degradation rates of cytoplasmic tRNA, rRNA and mRNA in rats are elevated after infection with Nippostrongylus brasiliensis.

The effects of a parasitic infection with the nematode Nippostrongylus brasiliensis on the degradation rates of cytoplasmic tRNA, rRNA and mRNA in rats have been investigated by measuring the renal excretion rates of the modified RNA catabolites N6-threoninocarbonyladenosine, pseudouridine and 7-methylguanine. Between days 9 and 13 post-infection when the expulsion of N. brasiliensis is usually the most pronounced, the degradation rates of the different RNA classes were significantly higher than in the control rats (P < 0.05) by, on average, +24% (tRNA), +34% (rRNA) and +26% (mRNA). We suspect that the elevated degradation rates of RNA are related to an increased production of reactive oxygen species by the host during the expulsion of N. brasiliensis.

Animals↗

PubMed1998

Measured consumption of commercial infant food products in German infants: results from the DONALD study. Dortmund Nutritional and Anthropometrical Longitudinally Designed.

BACKGROUND: Commercial food products intended for infants form an important part of the diet. Such products are defined as special dietetic food by food legislation. However, quantitative consumption data in the context of the current European Community (EC) food regulations have not been available up to now. METHODS: Six hundred eighty 3-day weighed diet records from 3-, 6-, 9-, and 12-month-old infants involved in the DONALD (Dortmund Nutritional and Anthropometrical Longitudinally Designed) Study were evaluated regarding overall and individual consumption of commercial infant food (CIF). Here, CIF was allocated to the food categories of the current EC directives. RESULTS: Four hundred eighteen varieties of infant food were recorded. The total CIF (formulae; beikost [any food or drink other than breast milk or infant and follow-on formulae]) reached percentages of the total food intake (including breast milk) of 51% (47%; 4%), 62% (33%; 29%), 53% (20%; 32%), and 37% (13%; 24%) at the ages of 3, 6, 9 and 12 months, respectively. Approximately 55% (95%) of the 3-month-old infants (range, 6-12 months) consumed some sort of CIF, but the highest amounts were observed at 6 months and the highest numbers of consumers at 9 months. Depending on the definition of "high consumers" of CIF, the individual consumption quantities (in grams per kilogram per day) differed by a maximum of 60% but high consumers were always found in the 6-month-old group. CONCLUSION: The high proportions of CIF in the diet during a critical developmental period call for a guaranteed high nutritional and safety quality of CIF and for realistic data on consumption patterns.

Breast Feeding↗

PubMed1998

Energy intake and growth of 3- to 36-month-old German infants and children.

Recently, new estimations of the energy requirements of infants and children were proposed as a basis of new FAO/ WHO energy requirements. We have compared the energy intake of 354 healthy, well-nourished infants taking part in the Dortmund Nutritional and Anthropometric Longitudinal Designed Study (3-day-weighted diet records) with these new estimated energy requirements. The energy intake of breast-fed and formula-fed infants and the energy intake of the 1- to 3-year-old children in the study population corresponded well with the new estimated energy requirements, although these were considerably lower than the 1985 FAO/WHO energy requirements. Breast-feeding rates were lower and the introduction of beikost was earlier than the current recommendations. Height and weight, which were taken as global indicators of the adequacy of the energy intake, were in good accordance with The Netherlands' third nationwide survey. Our data indicate that the new estimations of energy requirement seem to be more appropriate than the 1985 FAO/WHO energy requirements.

Body Height↗

PubMed1997

Determination of degradation rates of transfer and ribosomal ribonucleic acids in cultured rat hepatocytes by measuring N6-threoninocarbonyladenosine, dihydrouridine, and pseudouridine in medium using high-performance liquid chromatography.

Modified ribonucleic acid catabolites excreted into the medium by primary cultures of rat hepatocytes (2.3 +/- 0.42 x 10(6) cells/dish) during a 24-h cultivation period were quantified by reversed-phase high-performance liquid chromatography (fmol/10(3) cells): 613 +/- 81 dihydrouridine, 46 +/- 6 N6-threoninocarbonyladenosine, 1879 +/- 220 pseudouridine. On the basis of these excretion rates and the average frequency of occurrence of these modified ribonucleosides per cytoplasmic transfer ribonucleic acid (residues: 2.6 dihydrouridine, 0.22 N6-threoninocarbonyladenosine, 3 pseudouridine) as well as per cytoplasmic ribosomal ribonucleic acid (residues: 95 pseudouridine), the degradation rates of transfer and ribosomal ribonucleic acids were calculated. The degradation rate of transfer ribonucleic acid (fmol/10(3) cells/24 h) was 236 +/- 31 (via dihydrouridine) and 211 +/- 28 (via N6-threoninocarbonyladenosine) and that of ribosomal ribonucleic acid (fmol/10(3) cells/24 h) was 13.1 +/- 1.7 (via pseudouridine and N6-threoninocarbonyladenosine).

Adenosine↗