Influence of plasma modification on biological properties of poly(ethylene terephthalate).

Poly(ethylene terephthalate) film was modified with argon or perfluorohexane plasma to obtain hydrophilic or hydrophobic surfaces, respectively. Various biological experiments in vitro and in vivo were chosen in order to evaluate the influence of such treatment on biocompatibility. Plasma modification does not cause toxic effects and does not influence disadvantageously the tested polyester biocompatibility. The huge changes in surface energy cause only minor changes in the biological behaviour of the samples.

[Biological studies of Gore-Tex vascular prostheses]. / Badania biologiczne protez naczyniowych Gore-Tex.

In 1981 we received the Gore-Tex PTFE vascular prostheses, 12 mm in diameter, in order to test their value. Experimental studies were carried out on 6 piglets, in which 5 cm long sections of the prostheses under study were grafted into surgical defects of the thoracic aorta. The dissections were made 1, 3, 6 months after grafting, each time detailed pathomorphological studies were carried out. The results show that PTFE prostheses, grafted into a piglet thoracic aorta was surrounded by fibrinous connective tissue. The tissue on the outside of the prostheses differs in histological structure from that inside. After 6 months it was found that the prosthesis has inside a thin layer of fibrinous connective tissue, connected to the prostheses wall; the layer did not constrict the internal diameter. The Gore-Tex prostheses fulfill biological requirements on vascular prostheses after their grafting into operational defects of the aorta.

[Clinical studies of Gore-Tex vascular prostheses. A review of the literature]. / Badania kliniczne protez naczyniowych Gore-Tex. Przeglad literatury.

Reconstruction of arterial and venous vessels by means of polyester and teflon vascular prostheses gives unsatisfactory distant results. Three-year long observations show that only 50% are satisfactory. The best results are achieved when autogenous veins are grafted. It is estimated, however, that in 15-30% of cases the veins are useless as prosthetic material because of various pathological changes. New types of vascular prostheses have to be searched for, such that would meet all requirements. In the end of the 1970 the Gore Firm worked out a unique technological process of making vascular prostheses of pure, distensible or reinforced polytetrafluoroethylene, porous in structure. In 1970 such prostheses, named Gore-Tex, were subjected to experimental studies. The present paper discusses first publications on the prostheses, the publications included ample statistic material and discussed perspectives in vascular surgery that the new type of vascular prostheses opens.

[Biological testing of hemostatic properties of various collagen preparations]. / Badania biologiczne hemostatycznych wlasciwosci róznych preparatów kolagenowych.

In experiments on animals a method of studying electrostatic and hemostatic properties of collagens was worked out. Following hemostatic collagen sponges were used: Superstat (Interface Biomedical Laboratories Corporation, USA), Hemostatic Felt (B. Braun, BRD), collagen sponge and collagen foil (Central Tissue Bank of Transplantation Institute, Medical Academy, Warsaw). Biological experiments were performed on rabbits in 4 groups, depending of the implanted material. Basing on surgical macro- and microscopic evaluation it was found that collagen preparations used in the experiments shorten the duration of bleeding of damaged liver, and that biological reactivity of studied collagen preparations is proportional to the duration of their resorption time in tissues. The shortest resorption time gave the Superstat.

[Experimental testing of the hydrogel dressing Geliperm]. / Badania doswiadczalne hydrozelowego opatrunku Geliperm.

The dressing materials used in the local treatment for dressing large defects of skin, subcutaneous and muscular tissues do not have the optimum protective and therapeutic properties. We carry out experiments tending to achieve new kinds of dressing impermeable for microorganisms, free from toxic, allergic, action and acridity and not evoking pathological tissue reaction in a long-lasting contact with the wound. What is more, the new dressing should hasten the cicatrization process of a wound and enable its control as well as soothe the pain if it is possible. Some of these properties were achieved by the usage of cross-linked hydrophilic polymers with high ability of water absorption, creating elastic gels in its presence. The dressing of this type called Geliperm was produced by Geistlich Sons Ltd. and BYK Goldbin-Konstanz firms. The methods of evaluation of hydrogel dressing materials comprising a preliminary, standard and qualifying evaluation were worked out in the Department of Experimental Surgery and Biomaterials Research Medical Academy of Wroclaw. According to the worked out scheme of experiments the Geliperm dressing was evaluated. We have discovered on the basis of the carried out experiments that the new generation of gel dressing has, to a large extent, the properties of the so called "ideal dressing".

[Tutoplast-Dura and Zenoderm-Corium implant--materials for tissue replacement. Experimental studies]. / Tutoplast-dura i Zenoderm-Corium implant--materialy do zaopatrywania ubytków tkanek. Badania doswiadczalne.

The results of experimental studies with the use of two biostatic materials: solvent-preserved human dura mater (Tutoplast-Dura--Pfrimmer-Vigo) and lyophilized porcine dermis (Zenoderm-Corium implant--Ethicon) as prosthesis of deficient, abdominal wall tissue are submitted. The studies were performed on an animal model and consisted on the evaluation of mechanical and biological qualities of the investigated materials as well as their surgical handiness and tissue tolerability. The application of knitted polyester net as a reinforcing agent for both materials was also estimated. Process of incorporation of the prosthetic material was investigated macroscopical at 3, 6 and 12 weeks after the implantation. The experimental trials revealed the usefulness of Tutoplast-Dura and Zenoderm-Corium implant in reconstructive surgery in account of their good biocompatibility and adequate, mechanical properties. It was stated that Tutoplast-Dura was characterized by remarkably better surgical handiness in comparison to Zenoderm-Corium implant. Additional mechanical reinforcement with polyester net was not necessary.

[Experimental research on the usefulness of the Dallos polyester prostheses in reconstructive operations of knee joint ligaments]. / Badania doswiadczalne nad przydatnoscia protez poliestrowych Dallos w operacjach rekonstrukcyjnych wiezadel stawu kolanowego.

Usage of allogenic grafts in surgery of severe injuries of knee joint may be necessary in spite of their disadvantages. Prosthesis Dallos made by Tricomed in Lódz has been tested taking into account its usage in reconstruction of knee sacral ligaments. Prosthesis was implanted into 7 piglets in place of the removed front sacral ligament. In the tests the mechanical requirements made for this kind of grafts were confirmed. However, an unfavourable influence of this prosthesis on the synovial membrane of a joint and weak overgrowth of the graft with connective tissue, which can be eliminated by usage of looser knitting, were noticed.

[Testing the usefulness of a provisional polyester prosthesis for augmentation in reconstructive operations of knee joint ligaments]. / Badania przydatnosci czasowej protezy poliestrowej do augmentacji w operacjach rekonstrukcyjnych wiezadel stawu kolanowego.

Prosthesis from polyester fibres 5 mm wide with loose knitting finished on both ends with teflon handles for fixing bones with a wholly aphid screw made by Tricomed company in Lódz according to its own idea was the subject of the test. The tests were made on 7 piglets. The prosthesis together with an autogenic graft taken from the middle third of a patella ligaments was implanted into the place of the excised front sacral ligament. The implanted prosthesis was characterised with a high biocompatibility, satisfying mechanical resistance and easiness of fixing of the tested graft. We noticed clinically and pertaining to autopsy the possibility of removing the allogenic graft after achieving the full healing of the autogenic graft without the possibility of hurting that last one.

[Experimental testing of Dexon, Vicryl and Gore-Tex mesh used to complete the abdominal wall]. / Badania doswiadczalne wchlanialnych i niewchlanialnych siatek Dexon, Vicryl i Gore-Tex do uzupelniania powlok brzusznych.

Injuries of abdominal integuments, operations and reoperations of hernias, injuries of a spleen, defects in the wall of the chest and diaphragm cause that the need for substitute materials and alloplastic materials for completing those defects is large. To satisfy this tests have been made experiments with absorbable--Dexon, made by Davis and Geck enterprise, Ethicon and non-absorbable--Teflon made by Gore-Tex enterprise according to the proposition of H. Kus. The experimental tests were made on 30 rabbits of the white New Zealand breed which weighted 2-3 kg. On the hypogastrium in the distance of 3 cm from the white line on its both sides defects of the size 2 x 3 cm were made. On the right side both fascial-muscular layers of the external and internal oblique muscle of abdomen were cut out but the peritoneum was left while on the left side only one layer was cut out. The defects were completed with nets and fixed with interrupted sutures and then with continuous suture. During the operation the behaviour of the nets in the operation area and the difficulties in connecting the nets with the animals' tissues were tested. Sections of the animals and macroscopic tests were made 7, 14, 21 and 90 days after the implantation of each surgical net estimating the process of healing and resorption of the absorbable nets. The state of the organs of the abdominal cavity was also estimated. Microscopic tests consisted of estimation of the histological specimens made from the tissues taken during the sections of the animals. At the estimation of the surgical convenience of the tested nets it turned out that each of them is very convenient. The differences were in the fact that the Dexon and Vicryl nets had little elasticity and extensibility and after cutting there was a little shredding of their edges. The Gore-Tex net, on the other hand, due to its specific spongy structure, had little extensibility, good elasticity and a complete lack of shredding of the edges after cutting. The macroscopic tests carried out in the planned terms did not showed any deformation or handicap of the functions of the abdominal integuments. The nets implantation did not cause displacement of the internal organs nor intraperitoneal adhesions. On the basis of the microscopic investigation it was noticed that the absorbable surgical nets underwent progressing resorption in the tissues in the period of 21 to 90 days after the implantation.(ABSTRACT TRUNCATED AT 400 WORDS)

[Testing tissue reactivity to surgical sutures using a personal point method]. / Badanie odczynu tkanek na nici chirurgiczne z zastosowaniem wlasnej metody punktowej.

In the Institution of Experimental and Biomaterial Research Surgery of Medical Academy in Wroclaw works on biological methods of estimation of different biomaterials including, first of all, surgical threads have been carried out for 30 years. The purpose of this work is to define the local biological reaction on the implanted absorptive and non-absorptive surgical threads. The present estimation of reactivity of surgical threads depended on a description of a great number of histological samples and on observation of numerous microscopic fields for each tested thread. It required long and tiring descriptions the analysis of which was made difficult and often led to non-objective conclusions. The presented punctual system depends on observation of the field of vision in a biological microscope which includes transverse cross-section of the implanted thread together with the surrounding tissues. The estimation of the histological samples in magnification of 45 times allows to define the range of infiltration of tissues with inflammatory cells in comparison with the diameter of the implanted thread. Observations in magnification 120 times allow to differentiate cells included in non-specific inflammatory process. The worked put punctual system enables to define the level of tissue reaction on the basis of uniform criteria.

[Experimental studies of Dallon vascular prostheses after superficial alkaline hydrolysis]. / Badania doswiadczalne protez naczyniowych Dallon po powierzchniowej hydrolizie alkalicznej.

Within the research on improving polyester vascular prostheses DALLON there was made a superficial alkaline hydrolysis in the manufactured product, which greatly enhanced the prostheses wettability without lowering their resistance parameters. In preliminary laboratory research and in biological studies in vitro, made with model prostheses and with those having been hydrolyzed, the results were better for hydrolized ones. Biological studies in vivo were made on piglets by implanting the prostheses into surgical defects of the thoracic aorta. In the course of the operations it was found that the prostheses were, apart from having better wettability, far more tight intraoperationally, as compared to the model ones. Pathomorphological studies, carried out 3 and 6 months after the operation, showed that, besides the hydrolized prostheses being less calcified, there were no significant qualitative and quantitative changes in the tissues around the implanted prostheses.

Radiosterilized polyester knitted nets Dallop.

Polish surgical polyester knitted nets Dallop sterilized by radiation were implanted and tested on Wistar rats. The results of the experimental evaluation are positive and lead to the conclusion that the Dallop radiosterilized polyester nets may be used in humans. The evaluated knittings fulfill the most up-to-date biological requirements and may be utilized as implantation material for plastic and reconstructive surgery.

[Effect of plasma modification on biological properties of polyethylene terephthalate foil]. / Wplyw modyfikacji plazmowej na wlasciwosci biologiczne folii z politereftalanu etylenowego.

Film of poly(ethylene terephthalate) modified with plasma of pure argon and with mixture of argon and perfluorohexane. Wettability of surface, toxic influence, reaction of tissues and influence on the blood-clotting system of modified samples were tested. Plasma was modification allowed to obtain PET both with hydrophilic and hydrophobic surface. We did not observed the increase of toxicity and of the reaction of tissues in comparison with the initial film. Modification with plasma of perfluorohexane had the test influence on the blood-clotting system.

[Experimental studies of new Polish hydrogel dressing materials HDR]. / Badania doswiadczalne nowych polskich opatrunków hydrozelowych o symbolu HDR.

Recently the spectrum of dressings was enriched, incorporating the so-called hydrogel dressing, made by Geistlich Sons Ltd. and Byk Goldbin-Konstanz referred to as "Geliperm". In Poland, HDR hydrogel dressings' technology was launched by Institute of Radiative Technology, Lódz+ Polytechnic. This type of dressing is obtained by radiative cross-linking of hydrophilic polymers. The experimental studies of the new Polish hydrogel materials were accomplished at the Department of Experimental Surgery and Biomaterials Research, the Chair of traumatologic Surgery, Medical Academy of Wroclaw. These studies concerned three kinds of hydrogel dressings, different in composition and irradiation conditions. HDR-1 10% of polyvinylpyrrolidone+, 1.5% of agar, 1.5% of polyethylene glycol 300, irradiated with 30 kGy (gamma radiation of 60Co); HDR-1 with neomycin--formula as above plus neomycin sulfate (2.5%); HDR-2 6% of polyvinylpyrrolidone++, 1% of agar, 1.5% of polyethylene glycol 300, irradiated with 25-27 kGy (gamma radiation of 60Co). The usable properties of the HDR dressings approximate those of the West German products. Owing to the lab tests, biological and in vitro examinations we had performed, it was possible to state that aqueous extracts of the hydrogel dressings subjected to assessment did'nt exhibit hemolytical or toxic activities in cellular tests, at the same time lacking an irritating effect. They cause a minimal tissular reaction and accelerate the process of healing.

[Attempts at modification of the polyester vascular prosthesis]. / Próby modyfikacji poliestrowych protez naczyniowych.

Polyester vascular bilaterally velour prostheses produced by the Enterprise of Medical Products TRICOMED in Lodz were modified through: putting negative electric charge on the internal surfaces of prostheses; additional cleaning with ethanol; covering of the surfaces of prostheses with silicone preparation; two-sided covering of the surfaces of prostheses with collagen by the radiative method; covering of the surfaces of prostheses with chitosane. Laboratory investigations, investigations of hemolytic and toxic effects of aqueous as well as experimental investigations has been carried on piglets. During these investigations it was observed that the carried preparations caused multiple increase of electrical conductivity of proper and dry remnant after evaporation of the aqueous extracts. Hemolytic and toxic effects were not observed. In radiological and pathomorphological investigations it was observed that none of the preparations used for modification of vascular prostheses influenced improvement of their biological properties. In comparison with the initial prostheses DALLONR these prostheses evoked a greater reaction of tissues which was manifested with a thick internal layer causing narrowing of the lumen of the section with prosthesis or closing it. A small improvement of the biological properties of the prostheses were achieved after cleaning them with methanol. However, this improvement is so small that it does not justify changes in the existing technology.

[Absorption of chitosan applied to polyester discs in rats after implantation]. / Wchlanianie chitozanu naniesionego na krazki poliestrowe po implantacji u szczurów.

Experiments have been made on white rats implanting polyester blocks covered with chitosan into the peritoneal cavity and to the abdominal wall skin. Before implantation the material was sterilized with ethylene oxide or radiation. The animals were subjected to autopsy 3, 7, 14, 21, 25, 30, 35, 40, 45, 50, 55 and 60 days after implantation with macroscopic and microscopic evaluation. On the basis of the carried out experiments it was stated that the disintegration of chitosan proceeded not uniformly. The resorption time of chitosan oscillated in the range of 45-60 days and it was accompanied by rather strong specific inflammation process. It was characterized with fibrin effusion and with appearance of multi-flapped neutrocytes. Essential distinctions in the resorption process of depending on the sterilization mean of the blocks as well as on the place of implantation were not stated.

[Experimental testing of hydrogel dressings POLGEL based on the basis of synthetic monomers]. / Badania doswiadczalne opatrunków hydrozelowych POLGEL opartych na bazie syntetycznych monomerów.

In the Department of Experimental Surgery and Biomaterials Research in Wroclow Medical Academy standard and qualifying evaluation of 5 kinds of hydrogel dressings POLGEL produced in the Institute of Physico-Chemistry and Technology of Polymers of produced in Silesian Polytechnique has been carried out. Dressings Polgel were obtained as a result of copolymerization of acrylamide and methylene-bis-acrylamide in aqueous solution. On the basis of introductory experiments for qualifying evaluation dressing Polgel M modified with glycerin in the form of foil and dressing Polgel T--in the form of jelly were chosen. Both kinds of dressings did not cause haemolytic, toxic or irritative effects. In pathomorphological experiments moderate tissues reaction was noticed what signifies good biological characteristics of the evaluated dressings. The process of healing of injuries treated with dressings Polgel M proceeded well and epidermis creating was quicker in comparison with injuries treated with traditional dressing. On the basis of the carried out experiments it was noticed that dressings Polgel M and T satisfy the requirements made for the type of materials.

[Changes in the level of selected laboratory parameters in blood after implantation of chitosan fibers]. / Zmiany w poziomie wybranych parametrów laboratoryjnych krwi po implantacji wlókien chitozanowych.

The tests were carried out on rats of the Wistar tribe to the peritoneal cavity of which chitosan fibres were implanted. The blood for the tests was taken in 3, 7, 14, 30 and 60 days after the implantation. In the blood hematological, biochemical and clotting system parameters were marked. Moreover they made pathomorphological tests of the tissues surrounding the implanted material and laboratory and biological tests of aqueous extracts from chitosan fibres. The shown quantitative changes in the level of the marked parameters of blood to the 14th day of observation are connected mainly with toxicity of chitosan fibres, whereas to the 30th and 60th day-with the process of biodegradation and resorption of collagenous fibres.

[Changes in the level of interleukin-1 beta and interleukin-6 after implantation of selected medical materials. Introductory report]. / Zmiany w poziomie interleukiny-1 beta i interleukiny-6 po implantacji wybranych materialów medycznych. Doniesienie wstepne.

Evaluation of biomaterials with the help of routine methods not always allow full and explicit stating of their toxicity. That is why we still seek new methods of evaluation of biocompatibility on the cellular level. Usage of changes in activity of interleukin after biomaterials implantation creates such a possibility. The aim of this work as use of changes in activity of cytokines IL-1 beta and cytokines IL-6 for evaluation of biocompatibility of chosen medical materials. The tests were made on mice to whom polyester and aramid fibres as well as discs of rubber drains were implanted into the peritoneal cavity. Evaluation of the changes of the level of interleukin-1 beta and interleukin-6 was made in the fluid from the peritoneal cavity 3, 7, 14 and 21 days after implantation. Introductory tests of changes in the level of IL-1 beta and IL-6 after implantation of biomaterials with different degree of biocompatibility allow to assume that testing their activity may be useful in evaluation of their toxic effect.

The biological assessment of the chitin fibres.

On the basis of carried laboratory tests of the aqueous extracts, such as pH evaluation, electric conductivity and dry residue assessment we can stated that the obtained results are within the limits of the standards and are comparable to these given for similar kinds of medical devices, e.g. for Dexon sutures: pH--6.10; electric conductivity--31 MicroScm-1; dry residue after evaporation--0.0014 g/100 cm3. The mean percentage of hemolysis counted from the three samples made for chitin extracts was 0.86% and did not exceed the value of 1% which is accepted by the standards. In the assessment of the cytotoxicity which was carried out on the mouse fibroblasts, the proper morphological character was stated. Agglutination, vacuolisation, nor cells membrane lysis were not observed. The number of cells separated from the matrix were identical as in the control cultures. The increased number of the dead cells and decreased proliferation of the cells in the cultures containing the chitin extracts, were probably due to the ethylene oxide residues, which was used for sterilisation of the fibres. The assessment of the intracutaneous reactivity of the chitin extracts showed the lack of the irritation influence and the index of primary irritation was of no importance at all. The pathomorphological findings, which included macroscopic and microscopic evaluation, specially carried out after the implantation, showed the greater biocompatibility of the tested chitin fibres in comparing them to the Maxon sutures. The healing process of these fibres included the short exudative phase, which was more significant than in Maxon sutures reaction followed by the proliferation phase, which ended with the development of the connective tissue capsule. The connective tissue penetrated among the single chitin fibres. After longer observation periods (more then 30 days) the thickness of the capsule decreased. The number of the chitin fibres did not change over the observations periods, however the change of the colour of the fibres was observed. In our opinion it is the sign that the process of resorption has already started. The tissue reactions after implantation of the chitin fibres can be compared to those observed for monofilament suture Maxon. On the basis of all these observations, assessments and findings we can stated that the chitin fibres fulfil the basic biological requirements set up for the bio-medical devices.