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Biomedical subjects

M Chvapil

Publications and source records attributed to M Chvapil.

At least 235 records · Page 13Linked to original sources
PubMed1965

A study of the biosynthesis of collagenous and non-collagenous proteins and of the proline/hydroxyproline ratios of collagens isolated from embryonic tissues.

1. After incubation of chick-embryo skin slices with [(14)C]proline for 2hr. the specific activities of [(14)C]proline and [(14)C]hydroxyproline in soluble and insoluble collagens and [(14)C]proline in non-collagenous proteins were determined as well as the total amounts of both imino acids in these proteins. On the basis of these results it was demonstrated that soluble collagens having a high proline/hydroxyproline ratio are contaminated with non-collagenous proteins. 2. It was found that, in the presence of a mixture of amino acids in the incubation medium, the rate of synthesis of soluble collagen is significantly decreased. 3. The metabolic activity of collagenous proteins is related to their solubility, but that of non-collagenous proteins is not.

Journal Article↗
PubMedDate not supplied

Vitamin E reduction of lipid peroxidation products in rats fed cod liver oil and ethanol.

The purpose of this study was to investigate the effects of vitamin E supplementation on ethanol- and cod liver oil-induced lipid peroxidation. Adult male rats received diets containing ethanol, cod liver oil and supplemented with vitamin E for 28 days. Following treatment, hepatic conjugated dienes, lipid fluorescence, and exhalation of ethane were measured as indices of lipid peroxidation. Ethane expiration over a 3-hour period was reduced by 96% in rats fed ethanol supplemented with vitamin E. Exhalation of ethane was increased by CLO feeding but was reduced 89% in the CLO-fed rats supplemented with vitamin E. In addition, ethane production was elevated in rats fed ethanol plus CLO compared to rats fed diets containing CLO supplemented with vitamin E. Supplementation of the CLO diet with vitamin E also significantly decreased hepatic conjugated fatty acid dienes levels. Levels of hepatic conjugated fatty acid dienes from rats fed ethanol plus vitamin E were reduced 91% compared to rats fed ethanol diets. Additionally, hepatic lipid fluorescence expressed as per mg of hepatic phospholipid basis was also significantly increased in rat groups fed vitamin E, ethanol, and cod liver oil diets. Where vitamin E was added to these same diets a significant decrease of hepatic lipid peroxidation products occurred. The observed reduction in lipid peroxidation by vitamin E may be useful to retard lipid peroxides derived materials involved in the development of alcoholic liver diseases.

Animals↗
PubMedDate not supplied

Early changes in the chemical composition of the rat lung after silica administration.

A group of 200 g male Sprague-Dawley rats was injected with 75 mg of quartz (less than 5 mu particle size) and changes in lung DNA, noncollagenous protein, total lipids, and collagen were studied after 6, 24, 72, 96, and 144 hr. Another group of rats received 10, 30, 59, and 75 mg quartz and the above lung analysis was performed 6 days later. Control rats received saline only. Both sets of experiments indicate that striking changes in the above parameters occur very early. The sequence of statistically significant changes was: lung weight (24 hr), DNA (24 hr), noncollagenous proteins (72 hr), total lipids (72 hr), collagen (144 hr). At the dose of 30 mg quartz/lung all the above parameters were significantly increased within 6 days after the lung injury. It is proposed that in early stages of experimental silicosis an excessive amount of collagen accumulates in the lung. Later, some of the deposited collagen is resorbed. This indicates that in the course of the silicotic fibroproliferative inflammation, the balance between collagen deposition and degradation varies.

Animals↗