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1

The influence of immune system stimulation on encapsulated islet graft survival

100%
Orlowski T. M., Godlewska E., Tarchalska M., Kinasiewicz J., Antosiak M., Sabat M.
Archivum Immunologiae et Therapiae Experimentalis
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2005
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vol. 53
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issue 2
180-184
EN
The aim of this study was to determine the influence activating of the recipient immune system on the function of microencapsulated islet xenografts. The skin of WAG or Fisher rats and WAG free or encapsulated (APA) Langerhans islets were transplanted to healthy or to streptozotocin diabetic BALB/c mice. Skin grafts were performed following the method of Billingham and Medawar. Rat islets were isolated from pancreas by the Lacy and Kostianovsy method and encapsulated with calcium alginate- poly-L-lysine-alginate according to the 3-step coating method of Sun. The transplantation of encapsulated WAG islets, despite activation of the host immune system, restored euglycemia for over 180?100 days. A subsequent skin graft taken from the same donor was rejected in the second set mode, but euglycemia persisted. In diabetic recipients, impaired immune response was corrected by successful encapsulated islet transplantation. In diabetic mice, strong stimulation with 2-fold skin transplantation induced primary non-function of grafted islets despite their encapsulation. The survival of an islet xenograft depends on the level of activation of the recipient immune system. The immune response of diabetic mice was impaired, but increased after post-transplant restitution of euglycemia. Microencapsulation sufficiently protected grafted islets, and remission of diabetes was preserved. However, after strong specific or non- -specific stimulation of the host immune system, non-function of xenografted islets developed despite their encapsulation. Therefore, islet graft recipients should avoid procedures which could stimulate their immune systems. If absolutely necessary, the graft should be protected by exogenous insulin therapy at that time.
2

Biohybrid artificial organs in therapy of systemic disorders

100%
Jankowski T.
Biotechnologia
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1999
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issue 1
45-58
EN
Transplantation of cells and tissues secreting a desirable therapeutic product shows a potential in the treatment of many human diseases such as diabetes, hemophilia, dwarfism, immunodeficiencies, anemia, hypocalcemia, and some neurodegenerative disorders. To avoid graft rejection, the transplanted tissue is immunoisolated in a semipermeable membrane, thereby creating an implantable biohybrid artificial organ. A number of encapsulation systems such as vascular implants, diffusion chambers, and microcapsules have been developed for cell therapy. The encapsulation membrane should allow for diffusion of nutrients, dissolved gases, and wastes and should be impermeable to the components of the immune system, including cellular and humoral components. Encapsulation cell technology offers a solution to the problem of donor organ supply, not only by potentially allowing the transplantation of cells and tissues without immunosuppresion, but also by permitting use of tissue isolated from animals. However, further research is required in the areas of encapsulation device design and tissue supply from primary or cell-culture sources.
3

Cryopreservation of plant tissue culture

100%
Makowska Z., Kotlinska T.
Biotechnologia
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2001
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issue 2
126-134
EN
Three methods of cryopreservation: vitrification, encapsulation and slow freezing were discussed. The factors having influence on long-term storage in liquid nitrogen as selection of plant explants, media, optimal condition for regeneration and growth of plants were described. Practical utilisation of vitrification method and obtained results on garlic (Allium sativum L.) are given as an example. Vitrification involves treatment of samples with cryoprotective substances, dehydration with highly concentrated vitrification solution, aimed at water removal from the cells in order to protect them against destruction because of liquid nitrogen influence. This method offers a possibility to store plant material for a long time without any modification and contamination. The aim of the study is to develop a useful method for cryopreservation of apical meristems of garlic (Allium sativum L.) bulbils. The apical meristems of garlic bulbils were treated with PVS 3 solution containing 50% sucrose and 50% glicerol. The time of treatment of explants with PVS 3 was from 0 min to 240 min, then samples were plunged into liquid nitrogen (LN2) where they were kept for 1 hour or 30 days. Rapid heat up was achieved by plunging the samples in a 45oC water-bath until cryoprotectant solution became liquid. After cryopreservation, survival and regrowth on MS (Murashige and Skoog) medium were observed. Results showed that the best kind of explants giving high percentage of regeneration were meristems with two leaves primordia about 1 mm of diameter and about 3 mm in length.
4

Entrapment of immobilised in situ intracellular lipase of Mucor in microporous capsules

75%
Antczak T., Bugla J., Mastalerz M., Niemiec A., Szeja W., Slek M., Galas E.
Biotechnologia
|
2000
|
issue 4
142-151
EN
Lipases Mucor circinelloides and Mucor racemosus immobilised in situ were closed in microporous polysacharides hydrophilic gel cross-linked using a solution of calcium salts. In order to increase the porosity of polysacharides matrix during its cross-linking oligomer molecules of ethylene oxide (optimal Polikol 1000) were incorporated in the structure of the matrix. Then the oligomer was removed by acetone extraction. The obtained biocatalyst preparations were tested in hydrolysis of esters and esterification of oleic acid with butanol. The hydrolysis was carried out in water saturated organic solvents medium (n-hexane and diisopropylether). It was found that the efficiency of M. racemosus lipase immobilisation in hydrolysis of n-butyl oleate, n-butyl palmitate, n-butyl stearate, n-butyl laurate amounted to 60%. The efficiency of M. circinelloides lipase immobilisation in esterification of oleic acid with 1-butanol in hexane achieved 45%.
5

Encapsulation of immobilised in situ intracellurar lipases of Mucor

75%
Antczak T., Bugla J., Szeja W., Galas E.
Biotechnologia
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1999
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issue 1
172-179
EN
Endolipases associated with the cell structures of microorganisms are more active in comparison with purified enzymes. Due to the weak mechanical resistance lipases immobilised in situ cannot be used many times. The method of lipases encapsulation in polysacharides hydrophilic gels was elaborated. The lipases Mucor immobilised in situ were treated with oleic acid in hexane and then dispersed in an aqueous solution of sodium alginate or karagenate. Immobilisation of enzymes was achieved by intermolecular cross-linking of the polysacharide chains using the solution of calcium or potassium salts. The biocatalysts prepared under proposed conditions were active in hydrolysis of esters, as well as in esterification reaction. It was found that immobilised enzymes were active for a long time, were mechanically resistant and could be used many times in periodic and continuous processes.
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