Chitosan-Based High-Intensity Modification of the Biodegradable Substitutes for Cancellous Bone.

An innovative approach to treating bone defects is using synthetic bone substitutes made of biomaterials. The proposed method to obtain polylactide scaffolds using the phase inversion technique with a freeze extraction variant enables the production of substitutes with morphology similar to cancellous bone (pore size 100-400 µm, open porosity 94%). The high absorbability of the implants will enable their use as platelet-rich plasma (PRP) carriers in future medical devices. Surface modification by dipping enabled the deposition of the hydrophilic chitosan (CS) layer, maintaining good bone tissue properties and high absorbability (850% dry weight). Introducing CS increases surface roughness and causes local changes in surface free energy, promoting bone cell adhesion. Through this research, we have developed a new and original method of low-temperature modification of PLA substitutes with chitosan. This method uses non-toxic reagents that do not cause changes in the structure of the PLA matrix. The obtained bone substitutes are characterised by exceptionally high hydrophilicity and morphology similar to spongy bone. In vitro studies were performed to analyse the effect of morphology and chitosan on cellular viability. Substitutes with properties similar to those of cancellous bone and which promote bone cell growth were obtained.

How does electron beam irradiation dose affect the chemical and antioxidant profiles of wild dried Amanita mushrooms?

As with all mushrooms, Amanita species demonstrates several conservation problems, due to a post-harvest life limited to a few days. Drying is one of the most commonly used methods in mushroom preservation. Food irradiation is another possible way to improve food quality and insure its security. Among the emerging irradiation technologies, electron beam irradiation has wide applications, allowing for high throughput, wide flexibility and potential, without any negative effect on the environment. The effects of different electron beam irradiation doses in Amanita genus, were assessed by measuring the changes produced on a wide variety of nutritional, chemical and antioxidant indicators. The evaluated profiles indicated differences between non-irradiated and irradiated samples, however a high similarity was observed among different doses. This finding advises that the highest assayed dose (10 kGy) be applied, ensuring a higher effectiveness from a decontamination and disinfestation perspective, without having any stronger effects than those observed by the lower doses.

The genetic diversity of components of rye hybrids.

The genetic variability between 5 open-pollinated varieties of rye (Secale cereale L) and between the components of rye hybrids was estimated using PCR-based marker analysis. The 22 maternal single crosses and 11 restorers were the components of hybrids investigated in the preofficial trials at the Plant Breeding and Acclimatization Institute in Radzików (PBAI), the Danko Breeding Co. Ltd (DBC) and in the Poznan Breeding Co. Ltd (PBC) during the 2001 growing season. The PCR system using semispecific primers targeting the intron-exon junction sequences of plant genes was applied for the evaluation of the genetic diversity of rye breeding materials. The genetic distances between varieties were relatively low. The coefficients of dissimilarity did not exceed 0,15. The highest average distance between maternal hybrids and restorers (0,28) was found in materials from PBAI, whereas in materials from PBC and DBC the average distances were lower and reached 0,21 and 0,20 respectively. The cluster analysis based on PCR data indicated that hybrid components that originated from different breeding centres exhibited different genetic characters.

Semi-specific PCR for the evaluation of diversity among cultivars of wheat and triticale.

The usefulness of a semispecific PCR system for the evaluation of genetic diversity among selected cultivars of wheat (Triticum aestivum L.) and triticale (x Triticosecale Wittm.) was investigated. A comparison was made of the diversity among cultivars of both species as revealed by primers targetting the semi-conservative sequences of the intron-exon junction. The main purpose of the study was the selection of the most informative primers from among the exon targetting (ET) and intron targetting (IT) primers of 12 to 18 bases in length. For triticale, the most satisfactory results were obtained using ET and IT primers of 18 bases in length. In wheat, complex and polymorphic banding patterns were generated by primers belonging to both groups, regardless of their length.