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Biomedical subjects

Z Dvorák

Publications and source records attributed to Z Dvorák.

15 recordsLinked to original sources
PubMed1999

[The human hepatocyte: I. A model for studying metabolism and toxicity of xenobiotics].

Isolated human hepatocytes have become one of the most attractive experimental approaches to the study of the specific metabolic functions of the human liver, interactions between liver cells and infectious agents, and metabolism and pharmacotoxicity of drugs. Particularly the primary cell culture model provides an in vitro system for investigating specific mechanisms in a precisely controlled conditions. In the present paper the legislative and ethical problems concerning availability of human liver samples, techniques developed for isolation, preservation and cultivation of hepatocytes are discussed. In addition, a comparison of human and rat hepatocyte models in the study of the metabolism and cytotoxicity of taxol is reviewed.

Animals↗
PubMed1990

Mechanical engineering problems in preserving biological objects by temperature lowering.

Analysis of dangers caused by mechanical refrigerating and liquid nitrogen systems used for low temperature preserving of biological material and safety measures to be adopted. Hazards are caused by moving or protruding parts of the machinery, its hot parts, noise and vibration, work in cold rooms, possible destruction of pressure vessels, refrigerant inflammation or explosion, breathing the refrigerant or its decomposition products, direct contact of the refrigerant with the skin or mucous tissues, depletion of stratospheric ozone or contamination of food-stuffs.

Equipment and Supplies↗
PubMed1986

Evaluation of protein mixtures in adults on the basis of scoring pattern deduced from Kofrányi's results.

Minimum protein requirements for adult males found by Kofrányi in testing protein mixtures were compared with amino acid scoring pattern in which total non-essential amino acids were also included. For protein mixtures composed of different ratios of animal and plant proteins the least minimum of protein required corresponded to the maximum of the courses of chemical score when non-essential amino acids, lysine, sulfur amino acids or tryptophan respectively were taken as limiting. Particular comparisons indicate that total non-essential amino acids ought to be included in amino acid scoring pattern.

Adult↗
PubMed1986

[Acid-base equilibrium in the blood in cattle in relation to the incidence of DFD (dark, firm, dry) meat].

We studied changes in the parameters of the acid-base balance of the blood in cattle before animal transport to the slaughterhouses, after transport, after stunning and before bleeding. At the same time we studied the occurrence of DFD meat by measuring the pH value of the muscle and by determining the meat color. We found out that the disorder of acid-base balance was less manifest, with respect to the large capacity of the buffer systems of the blood, than the changes caused by glycogenolysis in the muscle.

Acid-Base Equilibrium↗
PubMed1975

[Loss of nutritional value of proteins in meat products caused by thermal processing].

In certain cases, the proteins in meat products may be damaged during thermal processing to such an extent that their nutritional value is reduced. This might be caused above all by a loss in the availability of the essential and semi-essential amino-acids. Cooking of the meat produces no marked change in the availability of the amino acids. More marked changes are observed at temperatures needed for sterilization. The availability of cystine is in most cases affected by the length and temperature of sterilization, which is due to a reduction of its digestibility and to its degradation. The extent of the cystine degradation follows from the difference from the average reduction of the availability of the other amino acids. Since the sulphur-containing amino acids in meat proteins are limiting ones, this loss results in a reduction of the nutritional value of the proteins. Apart from cystine, lysine may also become less available if greater amounts of polysaccharides are present. The reduction of the availability can be so marked that lysine may be considered to be a limiting amino acid. In these cases, lysine is essential for the nutritional value of the proteins in such products.

Amino Acids↗