[Nutritional status and problems with obesity in relation to educational status in young people in the Czech Republic]. / Výzivový stav a problematika obezity u mladých lidí Ceské republiky ve vztahu ke vzdelání.

UNLABELLED: The cross section study was performed with the aim to detect health prone nutritional behaviour and describe its relationship to the education in the groups of 20-25 years old people. Two groups: 449 undergraduate medical students (UG) and 116 non-graduate control people (C) were compared in respect of their food habits (food frequency questionnaire), nutrition (3 days dietary records data) and health nutritional state (measurement of body weight, height, percentage of body fat using Harpenden calliper). UG male performed higher energy intake, however, they did not differ in BMI, but they showed lower proportion of body fat ¿95% CI:(-4.22; -4.18)% of body content¿, probably due to higher physical activity. UG female performed lower energy intake and lower body mass index in comparison to C ¿95% CI:(-4.18; -4.8) kg/m2¿. CONCLUSION: Higher level of education is associated with health prone behaviour and is reflected on health nutritional state already in age of early adulthood.

Influence of vitamin C status on the metabolic rate of a single dose of ethanol-1-(14)C in guinea pigs.

The rate of oxidative metabolism after a single i.p. dose of ethanol-1-(14)C was studied in male guinea pigs, previously treated with two different levels of vitamin C (traces or 0.5 g/100 g) in their diet for 5 weeks. While the body weight did not differ between these two groups after 5 weeks of the dietary regimen, the vitamin C concentration in the liver was five times higher in the group with the high vitamin C intake. The cumulative amounts of breathing 14CO2 measured at short time intervals during 24 hours after an ethanol-14C injection (23 mg ethanol and 160 kBq per kg body weight or 2.35 g ethanol and 165 kBq per kg body weight in a parallel experiment) were significantly different. The half-time of ethanol turnover reached a value of 5.1 h versus 6.9 h (9.9 vs 14.4 h in a parallel experiment) in the high and low saturated group respectively. The long-term pretreatment of guinea pigs with large doses of vitamin C accelerated ethanol metabolism. Improvement of the redox state and activation of the cytochrome P450 system in vitamin C-supplemented organism are considered to be the reason for the increased ethanol catabolism.

Influence of vitamin C status on ethanol metabolism in guinea-pigs.

Guinea-pigs were maintained for 5 weeks on a diet containing three different concentrations of vitamin C: a) traces (none added), b) medium (0.05% w/w) and high (0.5% w/w). Twenty-four hours before killing the animals received one i.p. dose of 3 g ethanol per kg body weight (a model of short-term acute intoxication). In a parallel experiment which lasted 5 weeks, the animals were treated every week with two i.p. doses of 1 g ethanol per kg body weight followed by the final acute intoxication (3g ethanol/kg) (a model of long-term chronic alcoholization). In both experiments, the guinea-pigs with the highest tissue concentration of vitamin C proved to have significantly decreased residual levels of ethanol and acetaldehyde in the liver and the brain, a decreased activity of alanine- and aspartate aminoacyl transferases in the serum and decreased contents of triacylglycerols and cholesterol in the serum and liver in comparison with the vitamin C-unsupplemented group. The regression curve expressing vitamin C levels versus residual ethanol and acetaldehyde concentrations in the liver confirmed the highly significant negative correlation between them. Administration of the guinea-pigs with large amounts of vitamin C appears to accelerate ethanol and acetaldehyde metabolism and reduce some of their adverse health effects.

[The role of dietary plant polyphenols in health maintenance]. / Uloha rostlinných polyfenolu v potrave pri ochrane zdraví.

Plant polyphenols are typical representatives of natural substances in foods of plant origin, in particular in fruit, tea and vegetables. They display multiple structure-conditioned interactions with various biomolecules. Their general property is the antioxidant and chelating effect and modulation of activity of various enzyme systems. In the diet they act mostly as health promoting factors during various chemical and physical stresses of the organism. They are antiatherogenic and anticarcinogenic, on the principle of inhibition of oxidative destruction of various oxylabel biological structures, inhibition of processes of bioactivation of carcinogens, blocking LDL oxidation and stimulating the activity of antioxidant and detoxication enzymes. Some of them have mutagenic properties in genotoxicity tests (quercetin, colours of red wine, phenolic acids of coffee), however, the results of animal experiments and epidemiological studies do not confirm the risk of neoplastic disease in subjects with a normal intake of these substances. The biological activity of plant polyphenols is part of the activity of other chemopreventive dietary constituents and essential nutrients. In this complex polyphenols act in many ways on the principle of synergism. The use of the health promoting properties of polyphenols isolate from plants and their administration in a pure state is not foreseen. However, under conditions it is desirable to increase the consumption of foods which are important sources of these substances.

[Color reaction in the detection of drugs using photooxidation on thin-layer chromatography]. / Barevná detekce nekterých léku fotooxidací na tenké vrstve.

Due to the action of light and oxidation some drugs applied to and developed on a thin layer give a colour reaction. As a result of photooxidation artefacts may develop directly on the thin layer.

Moderate alcohol consumption and vitamin C status in the guinea-pig and the rat.

The influence of regular moderate ethanol consumption on the status of vitamin C was followed in guinea-pigs and rats. In the guinea-pigs examined, 10-day consumption of ethanol (4.5 g per day and kg of body weight), administered in drinking water under a vitamin C-deficient diet, caused a greater decrease in the tissue concentrations and the body-pool of this vitamin than in the group without alcohol. In the rats, on the contrary, the daily consumption of ethanol (6% vol) during 10 months resulted in an increase in the body stores of vitamin C, especially in the liver, adrenals, kidneys, and lungs. Moreover, the biosynthesis of ascorbate from D-glucuronolactone in vitro was more intensive (by 30%) in the liver microsomes of alcoholized rats than in those of controls (without alcohol). These results indicate that the need of vitamin C during chronic consumption of moderate alcohol doses is enhanced. This is due to the participation of ascorbate in oxidoreducing processes connected with ethanol metabolism which leads to its irreversible destruction. In the rat, this loss is compensated by its enhanced biosynthesis, while in the guinea-pig it produces increased demands for its exogenous intake. If these are not satisfied, a partial vitamin C deficiency may occur, which potentiates the harmful effect of alcohol on the health status.

[Use of bromine in the detection of drugs using thin-layer chromatography]. / Pouzití bromu pri detekci léciv na tenké vrstve.

For colour identification of drugs on a thin layer bromine vapours were used. The investigated drugs were divided into those which after bromination gave a colour reaction and those which did not display this reaction.

Temporal changes of the lipid peroxidation in rats after acute intoxication by ethanol.

A group of male rats were intoxicated within 24 h by three successive i.p. doses of ethyl alcohol (7.5 g per 1 kg of the body weight). In parallel, a control group of rats were dosed i.p. with a physiological saline. At time intervals of 0 h, 4 h, 24 h, and 48 h after the intoxication, the content of thiobarbiturate-reactive substances (TBARS) as product of lipid peroxidation within the liver and brain microsomes and mitochondria was followed. In liver microsomes of the experimental rats there was a rapid increase (by 220%) in the content of TBARS during 4 h after the last application of ethanol, later on the level of lipid peroxidation decreased to the low original value. In other organelles examined only an insignificant increase in the content of TBARS was found. The results prove that an acute intoxication by ethanol does elicit an oxidative stress of the organism, expressed by a transiently increased production of TBARS. These oxidative and harmful changes for the cell structures are mostly located in the liver microsomes but a rapid repair of this damage follows. However, if such a short-term excessive abuse of alcohol is repeated more often, the above changes may lead to severe alcoholic injury to the liver tissue.

Effect of vitamins C and E on toxicity and mutagenicity of hexavalent chromium in rat and guinea pig.

The effect of simultaneous pretreatment with vitamins C and E on the toxicity and mutagenicity of K2Cr2O7 in rats and guinea pigs was evaluated. Dietary pretreatment of Cr(VI)-intoxicated rats with ascorbic acid or alpha-tocopherol normalized vitamin C levels in lungs but not in kidneys. The synergistic preventive effect of both vitamins was confirmed in the production of lipoperoxides in Cr(VI)-intoxicated rats. Simultaneous administration of vitamins C and E in guinea pigs prevented the decrease of vitamin C levels provoked by the oxidative effects of Cr(VI). The results of the micronucleus test in bone marrow showed that it was vitamin C that caused the antimutagenic effect against bichromate, in both rats and guinea pigs. The effect of vitamin E was demonstrated only in an increase of the ratio of NCE to PCE, i.e., in a decrease of the cytotoxic but not the mutagenic effects of hexavalent chromium.

Influence of age on the kinetics of vitamin C catabolism in guinea-pigs.

Pharmacokinetic analysis methods were used to evaluate the course of vitamin C catabolism in male guinea-pigs aged 3-5 weeks (weighting 255 g) and five months (weighing 570 g) given a diet containing no vitamin C. The vitamin C content of most of the organs and tissues of the younger experimental animals was depleted significantly more rapidly than in the older guinea pigs. At the same time, the half-time ascorbate elimination values were lower in the younger animals, in all the tissues analysed. As distinct from the older animals, vitamin C catabolism in the younger guinea-pigs had a biphasic character -- an extremely fast phase from the 1st to the 3rd day and a slower phase, comparable to the rate in older animals, from the 4th to the 17th day of administration of the scorbutogenic diet. The findings indicate that ascorbate metabolism in young organisms has specific characteristics, which ought to be taken into account when assessing and specifying the vitamin C requirements of the youngest section of the human population.

Changes in the cholesterol content of high-density plasma lipoproteins in guinea pigs in the presence of a raised exogenous cholesterol intake and different degrees of vitamin C saturation.

The cholesterol content of the high-density plasma lipoproteins (d over 1.1 g.cm-3) of guinea-pigs with experimental vitamin C deficiency, followed by realimentation with suboptimal (1 mg/animal per day) or optimal (10 mg/animal per day) doses of L-ascorbic acid for 6-9 weeks in the continued presence of an elevated alimentary cholesterol intake (0.5 g/kg diet), did not exceed 5% of the total plasma cholesterol concentration and did not alter significantly with changes in the degree of vitamin C saturation of the organism. The maximum total body tissue cholesterol concentrations were found in C-deficient guinea-pigs (plasma, adrenals) and in the group with partial vitamin C deficiency (liver, brain); the lowest values were found in the group whose organism was fully saturated with vitamin C. Under conditions of a raised cholesterol intake, ascorbic acid stimulated its elimination from the organism, but did not affect the proportion of plasma cholesterol bound in high-density lipoproteins.

Effect of flavonoids on vitamin C activity of D-isoascorbic acid.

Large peroral doses of D-isoascorbic acid, a vitamin C stereoisomer (50 mg per animal per day), were retained in the guinea-pig organism to a smaller extent than the same doses of L-ascorbic acid (vitamin C). Simultaneous administration of the flavonoids rutin and epicatechin increased the amount of D-isoascorbic acid retained in the liver, brain and wall of the small intestine by up to 100%, but four weeks after its extraction from the food the amount of L-ascorbic acid left in the guinea-pig organism still exceeded D-isoascorbic acid reserves. This difference, which was found in all the organs studied, was the largest in the groups simultaneously given flavonoids. In guinea-pigs which, like man, are dependent on an exogenous vitamin C supply, D-isoascorbic acid was metabolized at a manifestly higher rate than L-ascorbic acid, irrespective of whether flavonoids were administered or not. In liver, brain and small intestine wall homogenates, the oxidized forms of both stereoisomers were reduced in the presence of reduced glutathione, but the reduction rate of D-isodehydroascorbic acid was higher and it was stimulated by the two flavonoids more strongly than the reduction of L-dehydroascorbic acid. The stuterospecific.