BazTech - Yadda

1

Radicals initiated by gamma rays in selected amino acids and collagen

Przybytniak Grażyna., Sadło Jarosław, Dąbrowska Małgorzata, Zimek Zbigniew

Nukleonika

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2019

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Vol. 64, No. 1

11--17

EN

Calf skin collagen and three amino acids essential for its structure, namely glycine, L-proline and 4-hydroxyl-L-proline, were irradiated with gamma rays up to a dose of 10 kGy. Conversion of radicals over time or after thermal annealing to selected temperatures was monitored by X-band electron paramagnetic resonance (EPR) spectroscopy. Some experimental spectra were compared with signals simulated based on literature data from the electron nuclear double resonance (ENDOR) studies. The following phenomena were confi rmed in the tested amino acids: abstraction of hydrogen atom (glycine, proline, hydroxyproline, collagen), deamination (glycine, hydroxyproline), decarboxylation (hydroxyproline). Chain scission at glycine residues, radiation-induced decomposition of side groups and oxidative degradation were observed in irradiated collagen. The decay of radicals in collagen saturated with water occurred at lower temperatures than in macromolecules having only structural water. The paramagnetic centres were the most stable in an oxygen-free atmosphere (vacuum). Radical processes deteriorated the structure of collagen; hence, radiation sterilization of skin grafts requires careful pros and cons analysis.

2

Keratyna : źródła, właściwości, zastosowanie

Staroń P., Banach M., Kowalski Z.

Chemik

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2011

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Vol. 65, nr 10

1019-1026

PL

Celem artykułu jest scharakteryzowanie keratyny. Należy ona do rodziny białek fibrylarnych. Głównym źródłem naturalnego występowania keratyny są odpadowe pióra z przemysłu drobiarskiego. W skali globalnej powstaje ponad 4 mln ton tego odpadu w ciągu roku i należy go unieszkodliwiać. Keratyna charakteryzuje się dużą odpornością na czynniki fizyczne i chemiczne, dlatego niezwykle ważne jest poszukiwanie nowych metod przerobu odpadów keratynowych. Pozwoli to uniknąć problemu składowania odpadowego pierza. W pracy przedstawiono ponadto sposoby otrzymywania, degradacji oraz zastosowania keratyny.

EN

The aim of the article is the keratin characterization. Keratin belongs to the group of fibril proteins. The main source of natural occurrence of keratin are feathers from poultry industry. In the whole world there are 4 M tones a year of feathers, which should be utilized. Keratin has a high immunity to physical and chemical factors and it is the reason of searching for a new methods of keratin waste conversion. It would help to avoid a problem with storage of feather waste. The scientific work represents also methods of receiving, degradation and application of keratin.

3

Usefulness of spectroscopy for biomedical engineering

Olsztyńska-Janus S., Szymborska K., Komorowska M., Lipiński J.

Acta of Bioengineering and Biomechanics

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2008

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Vol. 10, nr 3

45-49

EN

Modifications of phenylalanine amino acid after its exposure to near-infrared (NIR) radiation have been investigated using ATRFTIR (Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy). The process of amino acid aggregation after its exposure to NIR has been observed. A possible mechanism of amino acid dimer formation has been proposed with the help of theoretical calculations of quantum mechanics (MP2 and B3LYP/6–31 G* level) using the GAUSSIAN 03 package. The usefulness of spectroscopy for biomedical engineering is discussed. ATR-FTIR appears to be a powerful tool for measuring tissue damage in aqueous environments.

4

Kinetic analysis of transport and hydrolysis of dipeptides, a new osmotic agent for peritoneal dialysis solution

Weryński A., Waniewski J., Wang T., Anderstam B., Lindholm B., Bergström J.

Biocybernetics and Biomedical Engineering

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2007

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Vol. 27, no. 1-2

71-82

EN

A mixture of dipeptides (DP) have been proposed as an alternative (to glucose and amino acids, AA) osmotic agent in peritoneal dialysis (PD) solutions. The following solutions were used: (1) the amino acids (AA) solution containing leucine, valine, lysine, isoleucine, threonine, phenylalanine and histidine (tyrosine was omitted because of its poor solubility), (2) the dipeptide (DP) solution containing leucyl-valine, lysyl-isoleucine, threonyl-phenylalanine and histidyl-tyrosine. Sixteen Sprague-Dawley rats were used in the experiments. Kinetic models were developed for estimation of the diffusive mass transport coefficient between the peritoneal cavity and blood (KBD), the DP hydrolysis rate coefficient (KH ) and the AA clearance in the body (KC). The calculations show that KH is about ten times smaller than KBD. Thus, the hydrolysis rate in the peritoneal cavity is much smaller than the diffusive transport rate of DP. KBD for AA appeared to be similar to KBD for dipeptides. KC was much higher than KBD for AA. This finding explains the rapid clearance of amino acids from blood. The peritoneal transport characteristics of AA and DP were similar; however, their kinetics in blood considerably differed. The DP solution resulted in a less pronounced increase of the AA concentrations in blood, suggesting that the DP solution could provide the AA supply/delivery in a more physiological way.