[The use of photodegradability of polyethylene in medicine. Own experiments]. / Wykorzystanie zjawiska fotodegradacji polietylenu w medycynie. Doswiadczenia wlasne.

AIM OF THE STUDY: The introduction ofphotodegradable polymers raises doubts among the natural profession. Photodegradation is a process of destruction of polymer, that is the entirety of physical and chemical change within the plastic, leading to irreversible changes in structure and deterioration of processing parameters. The prospect of release of products of degradation, possessing unknown capabilities is unsettling, as is the possibility of accumulation of compounds that could potentially be toxic, mutagenic and allergenic. Despite this, the use of photodegradable polymers is unavoidable in some cases. The applicability of degradable materials is easily visible in agriculture, horticulture and fruit-growing and medicine. The aim of the study is to asses the influence of selected additives over the process of accelerated aging of polyethylene. The aging was conducted in laboratory environment using lamps simulating the effect of natural sunlight in conditions similar to natural. MATERIAL AND METHODS: Preparation of polyethylene samples with sensitizers (TiO2-anatase, acacFe (II), acacFe (III)) added, aging of the sample in a UV chamber, estimating the surface changes in polyethylene after irradiation by measuring contact angle, spectroscopic analysis of polyethylene photodegradation, assessing endurance characteristics. The results of study show the highest degradation occurs if Ferrous (Iron (II)) acetylacetonate is used, with Ferric (Iron (III)) acetylacetonate showing slightly less effectiveness. TiO2-anatase indicates little influence over the process of degradation, on the contrary--a protective activity can be noticed, connected with white colour of this additive reflecting UV radiation. CONCLUSIONS: The results of the study clearly signify an interrelation between aging process and endurance characteristics of the material. The conducted analysis shows correlation between the number of carbonyl groups and endurance characteristics which, in turn, points to clear structural changes in polyethylene.

[Influence of oxidative stress on tissue regeneration]. / Wpllyw stresu oksydacyjnego na procesy regeneracji tkankowej.

The redox reactions involving oxidants and antioxidants play a key role in many biochemical pathways and cellular biosynthesis and regulation processes at the molecular level. Normally, there is the balance between oxidative and reductive processes in the organism. If oxidative processes are prevalent, it will result in oxidative stress. It leads to damage of many biological structures, resulting in impairment of many processes at the molecular level. Lipids and proteins are most sensitive to oxidative stress structures. Lipid oxidation can result in degradation of the cell membrane, whereas the oxidation of proteins can result in a change of their properties. It is suggested that oxidative processes accompany inflammation and affect their growth. This situation can lead to a number of serious diseases such as tumors. Many scientists claim that oxidative stress causes many pathological conditions. Enzymes and antioxidants, which are one of the body's defenses, can prevent oxidative processes.