Filiz Öner

Effect of use of slow release of bone morphogenetic protein-2 and transforming growth factor-Beta-2 in a chitosan gel matrix on cranial bone graft survival in experimental cranial critical size defect model.

Bone grafts, used for providing structural integrity of cranial vault remodeling, could not always integrate with the remaining bone structures. All efforts are focused on increasing incorporation of the applied bone grafts. Allografts were covered by chitosan so that slow release of bone morphogenetic protein-2 (BMP-2) and Transforming growth factor-beta-2 (TGF-beta-2) was achieved. Two hundred forty Wistar-Albino rats were distributed equally in 8 study groups. Study groups were designed as; defect group, autograft group, allograft group, chitosan group, allograft + chitosan, TGF-beta-2 group, BMP-2 group, and TGF-Beta-2 +BMP-2 group. Bone biopsies were obtained at second, eight, and 14th weeks. Bone regeneration was evaluated by morphologic studies detecting histologic bone healing and radiologic studies detecting bone density. Histologic findings were evaluated in 2 categories; tissue response to the implant and defect healing. Additionally, scanning electron microscopy for detailed morphologic evaluation was done. Bone density of the applied scaffold and the parietal bone at the same computed tomography section were measured in Hounsfield scale and this ratio was used for densitometry evaluations. Kruskal-Wallis test was used to analyze difference among groups according to the histologic and radiologic data. Pairwise comparisons were done using Mann-Whitney U test with Bonferroni correction. P < 0.05 was considered significant. In the morphologic studies, bone regeneration in BMP-2 group was found to be compatible with bone regeneration in gold standard autograft group and even better than it within 15 days. Chitosan is a biocompatible material. TGF-Beta-2 alone is not effective enough in bone regeneration; BMP-2 alone has a positive effect in every step of bone regeneration. Combining TGF-Beta-2 with BMP-2 does not lead to a better bone regeneration than using BMP-2 alone. A synergistic effect is not obtained by using these 2 factors together.

In vivo evaluation for rhGM-CSF wound-healing efficacy in topical vehicles.

The wound-healing efficacy of recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) was studied in a mouse model. Full-thickness wounds were treated with liquid crystalline, emulsion, and niosome vehicles alone and with rhGM-CSF. The control group was non-medicated. Observation of the vehicle groups with and without the rhGM-CSF displayed better healing profiles than the control group. The vehicles were also evaluated among themselves and it was noted that emulsion base and niosome base groups gave significantly better healing profiles and histological results than the liquid crystalline base group. Among the rhGM-CSF containing groups, emulsion formulation displayed a stronger wound-healing effectiveness compared to the other formulations. In vitro release characteristics of the recombinant protein from the three vehicle formulations were demonstrated with diffusion cells. Histological and immunohistochemical evaluation was performed on biopsies taken on the last day of the experiment.

Effect of slow-release 5-Fluorouracil on capsule formation around silicone breast implants: an experimental study with mice.

BackgroundCapsule formation around breast implants, development of tendon adhesions after tendon repair, intestinal brits after laparatomies, hypertrophic scars in skin incisions all are the results of excessive collagen synthesis to the extracellular matrix by fibroblasts. Any intervention that leads to cessation of collagen synthesis in these clinical situations may help to prevent these untoward results of wound healing. Although 5-fluorouracil (5-FU) is used mainly as a cytotoxic drug in chemotherapy protocols, it decreases cellular metabolism and blocks protein synthesis only at lower concentrations. Findings have shown that 5-FU downregulates fibroblast proliferation and differentiation in vitro. It has been used to treat fibroproliferative disorders of the eye and skin and is thought to inhibit thymidylate synthetase, blocking DNA replication.MethodsThis study used five treatment groups: (1) gelatin only, (2) silicone only, (3) silicone + gelatin, (4) silicone + gelatin containing 1 mg of 5-FU, and (5) silicone + gelatin containing 5 mg of 5-FU. The release kinetics of 5-FU from gelatin have been investigated by means of ultraviolet spectrophotometric analysis. Specimens were obtained on postoperative day 30. Gross evaluation and histopathologic examination were conducted for capsule formation and the development of inflammation.ResultsThe silicone group had the most prominent capsule formation among all the groups. The gelatin group was second, and the silicone + gelatin group was third. As compared with the other groups, the 5-FU–containing groups had the least capsule formation. The 5-mg 5-FU–containing group had the most inflammation. The silicone + gelatin group was second in inflammation. Although the silicone, gelatin, and 1-mg 5-FU–containing groups had the same means, the results of the silicone group showed the most divergent data within the group.ConclusionsBecause 5-FU loaded to a gelatin carrier for its slow release seems to prevent capsule formation around silicone blocks, it may be used to prevent capsule formation around silicone breast implants.

In vitro and in vivo evaluations of PLGA microsphere vaccine formulations containing pDNA coexpressing Hepatitis B surface antigen and Interleukin-2

Purpose. DNA-based vaccines encoding viral antigens have been shown to elicit immune responses in animal models. In this study, a plasmid DNA (pDNA) coexpressing the middle envelope protein of hepatitis B virus (HBV) and Interleukin-2 (IL-2) was incorporated into Poly (D,L-lactic-co-glycolic acid) (PLGA) microspheres and three different formulations were investigated for their potential as a vaccine delivery system. Methods. Emulsion solvent evaporation methods of water-in-oil-in-water (w/o/w) and oil-in-water (o/w) were used to generate three different formulations in which PLGA microspheres contained pDNA either encapsulated within or adsorbed onto the microspheres. Results. In vaccine formulation A2, prepared using the (w/o/w) method, pDNA was encapsulated within the microspheres. The other two formulations (B2 and B2a) were prepared using the (o/w) method and B2 contained pDNAs encapsulated within the microspheres while B2a contained pDNAs adsorbed onto the microspheres. pDNA loading efficiencies of A2, B2 and B2a were determined to be 15%, 25% and 45%, respectively. In vitro release of pDNAs from microspheres was evaluated for a 45-day period with no conformational changes and A2 displayed slower release than that of the B2 and B2a. When mice were immunized from anterior tibialis muscle using A2, B2 and B2a formulations containing 100 µg pDNA, antibody responses were detected for 6 months in mice sera. Conclusions. Although all PLGA microsphere formulations containing pDNA elicited antibody responses by the end of the 6th month, the antibody titers were found to be higher with B2 and B2a formulations in comparison to A2 formulation and the naked pDNA in saline.

Acceleration of distraction osteogenesis with drug-releasing distractor.

Objective: The aim of this study was to develop an internal distractor to release a drug to the distraction site during the distraction process and to investigate whether intermittent bone morphogenetic protein 2 (BMP-2)-containing chitosan hydrogel infusion will improve radiologic and histologic parameters of distraction osteogenesis (DO) when compared with control groups. Materials and Methods: Experimental groups were control group (n = 6), 2-&mgr;g single-dose BMP-2-chitosan hydrogel-infused group (n = 6), and 2-&mgr;g intermittent BMP-2-containing chitosan hydrogel-infused group (n = 6). In intermittent BMP-infused group, certain amount of BMP-2 loaded chitosan hydrogel injected into the distraction gap for controlled BMP release from the chitosan with every turning of the geared rod of the distractor. Radiologic and histologic evaluation methods have been conducted. Conclusion: The results of the analysis demonstrated that the newly developed distractor effectively stabilized the DO site while allowing intermittent BMP-chitosan infusion. Application of a BMP-2-chitosan hydrogel infusion to the distraction zone facilitates ossification. Intermittent infusion of BMP-2-containing chitosan hydrogel by use of a developed internal distractor increases ossification even more at the site of DO.

Approaches to Education of Pharmaceutical Biotechnology in Faculties of Pharmacy

Pharmaceutical biotechnology is developing rapidly both in academic institutions and in the biopharmaceutical industry. For this reason, FIP Special Interest Group of Pharmaceutical Biotechnology decided to develop a questionnaire concerning pharmaceutical biotechnology education. After preliminary studies were completed, questionnaires were sent to the leading scientists in academia and research directors or senior managers of various Pharmaceutical Biotechnology Companies in order to gather their views about how to create a satisfactory program. The objectives of this study were as follows: -To review all of the graduate and undergraduate courses which are presently available worldwide on pharmaceutical biotechnology in Faculties of Pharmacy. -To review all of the text books, references and scientific sources available worldwide in the area of pharmaceutical biotechnology. When replying to the questionnaires, the respondents were asked to consider the present status of pharmaceutical biotechnology education in academia and future learning needs in collaboration with the biotechnology industry. The data from various pharmacy faculties and biotechnology industry representatives from Asia, Europe and America were evaluated and the outcome of the survey showed that educational efforts in training qualified staff in the rapidly growing field of pharmaceutical biotechnology is promising. Part of the results of this questionnaire study have already been presented at the 57th International Congress of FIP Vancouver, Canada in 1997.

A new concept in treatment of burn injury: controlled slow-release granulocyte-monocyte colony-stimulating factor chitosan gel system.

Objective:The aim of the study is to investigate the effectiveness of the controlled slow-release granulocyte-monocyte colony-stimulating factor (GM-CSF) system in burn wound healing. Material and Methods:In vivo effect of controlled slow-release GM-CSF from chitosan gel on burn wound healing was evaluated on 18 Wistar-Albino rats, weighing between 250 and 300 g. They were randomly divided into 3 groups; (1) burned only group (n = 6), (2) burned + chitosan group (n = 6), (3) burned + chitosan + GM-CSF group (n = 6). Wound area was measured macroscopically. Hematoxylin and eosin and Massons trichrome stained sections were evaluated for wound healing and tissue response to the polymer. Results:The best healing process was observed with the controlled slow-release GM-CSF–applied group (group 3) in which the wound area was significantly narrowed. Conclusion:The study demonstrated the positive contribution of the single-dose controlled slow-release GM-CSF from chitosan gel on burn wound healing.

Epidermal Growth Factor (EGF) Wound Healing in Fluorocarbon and Chitosan Gels in a Rabbit Model

Wound repair follows a general scheme, a sequence of processes taking place in an orderly way: inflammation, repair and closure, remodelling and final healing. Growth factors are produced by the cells aiding the process and are effective during replacement and reconstitution1. A wound is defined as an interruption of tissue to a greater or lesser extent, which may affect skin, mucosa or organs. The specific sequence of different processes following wounding has one common aim: repair. In every wound type, the healing process runs through three stages, which partly overlap. The first one, the exsudative or inflammatory phase, is followed by the proliferative phase and finally the regenerative phase. Characteristic for the inflammatory phase, lasting approximately 72 h, is the activation of blood coagulation system and the release of various mediators from platelets. This is followed by the coagulation of blood, within 2–4 h inflammatory cell immigration starts and after 32 h fibroblasts are present in the wound site. The second phase of wound repair is characterized by proliferation and lasts from day 1 to a maximum of 14 days. Highly vascularized granulation tissue is formed and angiogenesis and neovascularization in the wound site starts. During the last phase of wound healing the production of new connective tissue is of main importance. If all epidermal layers are effected, re-epithelialization proceeds through the following three stages: migration of basal lamina cells, mitosis of cells migrating across the wound surface and maturation of newly generated cells. The final step in epidermal wound healing is characterized by cell maturation, leading to the regeneration of a defined epidermal layer. Keratinization starts and finally desmosomes promote attachment of cells to one another. The wound is closed and covered by mature epidermis2.

Drug Carrier Systems for Biotechnology Derived Products

Progress in biotechnology and increasing number of biotechnology derived drug products have led to the development of many new drug carrier systems.