Separation of elastin cross-links as phenylisothiocyanate derivatives.

A method has been developed for the separation and quantitation of desmosines in tissue samples. The tissue is treated with cold 10% trichloroacetic acid to remove collagen and hydrolysed in HCl vapours in sealed vials. Preseparation of desmosines from tissue acid hydrolysates is performed on a cellulose column, first eluted with n-butanol-acetic acid-water to wash out other amino acids and then with water to recover desmosines. Separated desmosines are then derivatized with phenylisothiocyanate and determined by reversed-phase high-performance liquid chromatography using a gradient system with sodium acetate pH 6.4 and acetonitrile. Desmosines were detected spectrophotometrically at 254 nm. The method was applied to the determination of desmosine in elastin, rat aorta and bovine ligamentum nuchae.

Effects of dietary trans-fatty acids on reproductive performance of Wistar rats.

1. Wistar rats were fed for three successive generations on a semi-purified diet, in which the fat was provided by butter, sunflower oil, rapeseed oil or hydrogenated vegetable fat, differing in the content of cis,cis-18:2 and trans-18:1 fatty acids. Effects of these fats on the composition of adipose tissue and reproductive performance were studied. Fatty acids were analysed using high-performance liquid chromatography. 2. The fatty acid pattern of adipose tissue was closely related to dietary fat composition and, established in the first generation, did not change significantly in successive generations of rats. 3. Hydrogenated fat adversely affected litter size, sperm morphology and regularity of oestrous cycle, and prolonged the period of gestation in experimental animals. Differences observed between the generations were not significant. 4. Hydrogenated fat decreased the level of serum testosterone in males, but the differences observed in levels of serum progesterone in females were not apparently related to the dietary trans-fatty acids.

Poultry Meat Irradiation - Effect of Temperature on Chemical Changes and Inactivation of Microorganisms.

Chilled (10°C) and frozen (-15°C) broiler carcasses initially artificially contaminated either with Pseudomonas aeruginosa , Salmonella typhimurium or Serratia marcescens (106cfu/g) were irradiated (Co60) with doses of 0.5, 1.0, 2.5, 5.0 and 10.0 kGy. Ps. aeruginosa was eliminated by doses of 1.0 - 2.5 kGy, S. marcescens by doses of 2.5 - 5.0 kGy and S. typhimurium by a dose of 10 kGy. Characteristic radiation odor increasing with radiation dose and temperature was well removed by heat meat preparation. Radiation resulted in increase of acid and peroxide values and destruction of thiamine (up to 57%/10 kGy) and riboflavin (up to 27%/10 kGy), lower increase of fat indexes and lower destruction of vitamins was observed at lower irradiation temperature. Content of amino acids was not affected by the treatment.

Determination of fatty acids as phenacyl esters in rat adipose tissue and blood vessel walls by high-performance liquid chromatography.

Twenty-two biologically relevant (6:0-22:6) saturated, monounsaturated and polyunsaturated fatty acids were separated by reversed-phase high-performance liquid chromatography after derivatization with phenacyl bromide. An optimal resolution of the critical combinations linolenic-myristic, docosahexaenoic-palmitoleic-arachidonic and palmitic-oleic acids and cis and trans isomers of octadecenoic (n9) and octadecadienoic (n9, 12) acids was achieved by continuous gradient elution with methanol-acetonitrile-water. Elution of mixtures of 6:0-22:1 fatty acids was completed within 80 min at a flow-rate of 1 ml/min. By the use of UV detection at 242 nm the detection limits for short- and long-chain fatty acids were found to be about 0.8 and 12 ng per injection, respectively. Linearity was tested up to 100 ng. The method was applied to the determination of fatty acids in rat adipose tissue and blood vessel walls of animals fed hydrogenated fat diets. The results are comparable to those obtained by gas chromatography and surpass the latter for the resolution of oleic and elaidic acids.

Physiological changes in laboratory rats caused by different housing.

Males rats of the Wistar strain (Institute of Physiology, CSAV ) were divided into six groups from the 30th to the 200th day of age. Rats (n = 54) were put into cages in various numbers (1, 2, 3, 4, 6 and 8 animals in a cage) and were weighed regularly and the consumption of water and food was measured. At the end of the experiment the animals were killed and the weight of some organs and haematological values were determined. During the experiment the highest weight was attained in animals with 3 or 4 members in one cage. The differences in weight were significant from the 80th day of age. The consumption of diets and water was not influenced significantly by the number of animals in a cage. On the 200th day, the differences between the groups were found in the weight of some organs, and in some haematological values.

Influence of diet composition on the weight gains of Wistar rat.

The composition of diets used for breeding and experimentation on laboratory animals is one of the important factors affecting the quality of the animals and the comparison of experimental data between different laboratories. Six diets used either at the Institute of Physiology, Czechoslovak Academy of Sciences in Prague, or in the Research Centre of Molecular Biology and Medicine, Academy of Sciences GDR in Berlin were analysed for moisture, crude protein, fat, fibre, ash, sodium, potassium, calcium, magnesium, phosphorus and chloride and fed to Wistar rats for 70 and 112 days. Weight gains of the animals were compared and statistically evaluated. The greatest weight gains were achieved with animals fed on the DOS 2b diet.