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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 150 osteotomies of rabbits' distal femur were fixed with absorbable self-reinforced polyglycolide (SR-PGA) rods coated with slowly absorbable polymers. In order to reduce the degradation rate of the SR-PGA construction rods were coated with n-butyl-2-cyanoacrylate, polydioxanone (PDS), poly-beta-hydroxybutyrate (PHBA), or poly-l-lactide (PLLA). Biocompatibility and the rate of biodegradation were evaluated in histological, histomorphometric, microradiographic, and oxytetracycline labeling studies. PDS, PHBA, and PLLA coatings showed good biocompatibility although there were scattered fluid accumulations around the rod in each group. Cyanoacrylate coating seemed to inhibit cartilage regeneration and cause the formation of considerable amount of connective tissue around the implant. The PGA core of the rod had totally degraded in 24 to 36 weeks in each coating group. Cyanoacrylate and PDS coatings were not detectable after 6 weeks while PHBA and PLLA coatings were still observed after 48 weeks. There were five (14%) non-unions in the cyanoacrylate coating group, one (3%) in the PHBA coating group caused by a purulent infection and none in the PDS and PLLA coating groups.
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PMID:A histomorphological study on self-reinforced polyglycolide (SR-PGA) osteosynthesis implants coated with slowly absorbable polymers. 217 71

The effect of suture material on healing of vascular anastomosis was examined. Four types of vascular grafts, i.e., autogenous vein, preserved human umbilical cord vein, expanded polytetrafluoroethylene and double velour knitted Dacron, were implanted into the abdominal aorta of 78 adult mongrel dogs using two kinds of absorbable sutures (multifilament polyglycolic acid: PGA and monofilament polydioxanone: PDS) and a nonabsorbable suture (polypropylene: PP). The macroscopic findings and the histologic examinations showed that hyalinoid degeneration and calcification resulting from tissue ischemia due to tight and long lasting suture loops interfered with tissue healing at the PP-anastomotic site. On the other hand, fairly good healing of the anastomoses was observed with absorbable sutures because of the reduction of ischemia. The absorbable suture-anastomoses could tolerate systemic blood pressure within one month after implantation, and there was no anastomotic disruption at 1000 mmHg pressure in the bursting test 12 months after grafting. From Dec., 1984, 55 anastomoses in 34 bypass-operations employing autogenous vein grafts were performed using PGA and PDS in 28 cases clinically. There were no anastomotic complications. In conclusion, the synthetic absorbable suture material, especially in the form of monofilament, seems to be most suitable for suturing or anastomosing autogenous small vessels at present.
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PMID:[The role of suture material on healing of vascular anastomosis]. 255 81

Wounds closed under tension have a tendency to stretch. To assess whether this stretching can be limited by inserting absorbable subcuticular sutures, 28 wounds, which involved elliptical excisions, were closed with PGA and PDS sutures in opposite halves of the same wound. PGA scars were found to be significantly wider than their PDS counterparts and were associated with greater hypertrophy at 6 months.
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PMID:A comparison of scar quality in wounds closed under tension with PGA (Dexon) and Polydioxanone (PDS). 255 50

The following article discusses the experimental and clinical reasons for using absorbable synthetic explants in retinal surgery. We have carried out experimental studies with absorbable synthetic explants bandmade from absorbable sewing threads: PG910, PGA and PDS; proving that these explants are well tolerated by the organism. Their reabsorption time is from 45 days using PG910, to 8 months using PDS; these periods are sufficient for proper anatomical healing of the retina to take place. We present 13 cases of extraction of Teflon explants after retinal detachment surgery; in none of these cases did re-detachment of the retina occur. Consequently, this induced us to introduce absorbable synthetic explants into retinal detachment surgery, using absorbable threads, having previously carried out an experimental study on rabbits. We present 10 cases of retinal detachment operated on with PDS from 95 cases operated on using absorbable synthetic explants; 100% anatomical healing of the retina was achieved. We consider this type of explant to be the ideal material for retinal detachment healing, due to the fact that its period reabsorption, being longer than those of the other explants, allows a longer indentation period.
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PMID:[Synthetic absorbable PDS explant for the treatment of retinal detachment]. 310 Jun 8

The loss of breaking strength and elasticity of five absorbable suture materials (polydioxanone [PDS-II], polyglycolic acid [PGA], polyglactin 910 [PG-910], polyglyconate [GTMC], and chromic gut) after in vitro incubation in sterile, Escherichia coli- and Proteus mirabilis-inoculated canine urine was studied. Biomechanical testing, in a controlled environment, was performed during the 28-day study period. Polydioxanone and chromic gut retained greater than 90% of their original strengths after 28 days of incubation in sterile urine and 87% of original strengths in E. coli-inoculated urine. Polyglyconate retained 24% and 18% of original strength, respectively, after incubation in sterile and E. coli-inoculated urine for 28 days. Polyglycolic acid and PG-910 retained less than 30% of original strength in sterile urine and only 7% in E. coli-inoculated urine after 21 days of incubation. In P. mirabilis-inoculated urine, loss of tensile strength and elongation was significant for all suture materials. Polyglycolic acid and PG-910 lost all strength after 24 hours of incubation. Polydioxanone lost all strength after 7 days of incubation, whereas GTMC retained 19% at day 7. Chromic gut retained 78% at day 7 and 16% after 21 days of incubation, however, the absence of normal phagocytic destruction of chromic gut in this in vitro study may have artificially elevated these values. In sterile urine with chemically modified pH, loss of strength and elongation was greater in alkaline urine than in neutral or acidic urine for all types of suture materials.
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PMID:In vitro loss of tensile strength and elasticity of five absorbable suture materials in sterile and infected canine urine. 836 3

Tissue generation by autogenous cell transplantation is one of the most promising treatment concepts being developed as it eliminates problems of donor site scarcity, immune rejection and pathogen transfer. Cultured cells are seeded onto a three-dimensional biocompatible scaffold that will slowly degrade and resorb as the soft and hard structures grow and assimilate in vitro and/or in vivo. The 3-D scaffold provides the necessary template for cells to proliferate and maintain their differentiated state. Ultimately, it defines the overall shape of the tissue-engineered transplant. The aim of this review is to describe and discuss the scaffold materials of natural and synthetic origin that are of specific interest to tissue engineers. This review is based on previous publications and our own experience in the use of biomaterials of natural and synthetic origin for tissue engineering applications. Biodegradable polymers which have been used for tissue engineering applications are mainly based on clinically established medical devices and implants. In the group of macromolecules of natural origin collagen, alginate, agarose, hyaluronic acid derivatives, chitosan, and fibrin glue have been used as scaffolds. Man-made polymers such as polyglycolide (PGA), polylactides (PLLA, PDLA), poly(caprolactone) (PCL), and poly(dioxanone) (PDS) have been studied as matrix material to guide the differentiation and proliferation of cells into the targeted functional premature and/or mature tissue. Appropriate selection of scaffold material with respect to the targeted tissue is essential. Today, biomaterials of choice remain to be those approved by the US Food and Drug Administration. In spite of that, novel biomaterials should be developed specifically designed for tissue engineering applications.
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PMID:An introduction to biodegradable materials for tissue engineering applications. 1137 17

The purpose of this study was to investigate, qualitatively and histoquantitatively, the tissue response of rabbit femur cancellous bone to polyglycolide (PGA), polydioxanone (PDS), polylevolactide (PLLA), and stainless steel pins under identical conditions. Eighty knees in 50 rabbits were operated on by inserting bioabsorbable pins (PGA, PDS, or PLLA) together with metallic Kirschner wire in 60, and two metallic Kirschner wires alone in 20 knees, while 20 knees served as intact controls. Follow-up times were 3, 6, 12, 24, and 52 weeks. Cancellous bone tissue response to implants was studied using histological, histomorphometrical, microradiographical, and oxytetracycline fluorescence methods. Residual fragments of PGA and PDS were seen at 24 weeks. Complete degradation of these polymers had taken place before 52 weeks. No signs of degradation of the PLLA pins were observed within the entire follow-up period. The osteoid formation surfaces at tissue implant-interface were statistically larger in all test groups as compared to intact controls. The number of macrophages at tissue implant-interfaces increased in all bioabsorbable implant specimens until 6 weeks, and with PGA until 12 weeks. No differences in the osseous response emerged when comparing groups of bioabsorbable implants with each other or with stainless steel group. Bioabsorbable pins and metallic Kirschner wires evoked an osteoconductive response in the cancellous bone surrounding implant, but the response intensity between implants displayed no differences. This suggests a simple, nonspecific walling-off new-bone front type of response. Consequently, the polymers possessed no specific osteostimulatory or osteoinhibitory properties. Within the follow-up, no significant differences in biocompatibility between the implants appeared, and no frank inflammatory foreign-body reactions occurred. The small-volume pins obviously did not exceed the local tissue tolerance and clearing capacity of the bone.
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PMID:Tissue response to polyglycolide, polydioxanone, polylevolactide, and metallic pins in cancellous bone: An experimental study on rabbits. 1677 15

The time requirement for endoscopic subperiosteal brow lift fixation is as little as 10-14 days. Many types of bioabsorbable fixation have been applied to this procedure, including bioabsorbable suture coupled with a bioabsorbable bone anchor, with excellent outcomes. Typically, the anchor and suture materials differ, each having their own hydrolytic strength loss profile. The dynamic relationship between the instantaneous state of degradation of the bone anchor and the suture components can affect fixation strength and failure mode, a poorly understood phenomenon. We examined the use of 2x5 mm PLLA-PGA (82:18) copolymer screws containing a suture eyelet in the head, paired with one of four types of bioabsorbable suture (2-0 and 3-0 Vicryl and 2-0 and 3-0 PDS-II), in a model system designed to mimic brow lift fixation. Constructs were inserted into a synthetic bone substrate and incubated in pH 7.4 buffer at 37 degrees C for up to 3 weeks, then loaded to failure. Initial failure loads were dependent upon suture size but not suture material, with 2-0 suture constructs (63-70N) failing at twice the load of the 3-0 suture constructs (30-35N). The following 3 week strength retentions were obtained: 40-55% for 2-0 and 3-0 Vicryl suture, 100% for 3-0 PDS-II suture, and 58% for 2-0 PDS-II suture constructs. The predominant failure mode was suture breakage at the knot, with the later intervals utilizing 2-0 PDS-II suture including some screw head failures. This suspension screw, when coupled with an appropriate suture, appears to have suitable mechanical properties for endoscopic brow lift fixation.
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PMID:In vitro characteristics of a bioabsorbable suspension screw and suture system for endoscopic brow lift surgery. 1741 97

Several surgical disciplines apply cartilage grafts for reconstructive purposes and have to overcome the scarcity of donor sites for this unique tissue. Employing the techniques of tissue engineering, cartilage might be generated in reasonable amounts for clinical purposes. Application of growth factors together with biochemical and biomechanical scaffold properties influence the process of ex vivo transplant production. The aims of this study are: 1) to investigate the influence of IGF-1 and TGFbeta-2 on tissue engineered human septal cartilage in vitro and in vivo after transplantation in nude mice; 2) to analyse the effect of the polydioxanone (PDS) content of the biodegradable Ethisorb E210 scaffold on the properties of the implanted constructs. Cells were three-dimensionally cultured on biodegradable Ethisorb E210 (PGA-PLA-copolymer fleeces with polydioxanone (PDS) adhesions), or on E210 scaffolds with a reduced polydioxanone content. Wet weight (ww), GAG-, and hydroxyprolin-content, as well as the cellularity of the neocartilage constructs were quantitatively evaluated. Additionally, the in vivo resorption of the two types of cell carriers was monitored. Addition of growth factors clearly increased the wet weight of the in vitro cultured constructs before transplantation. After transplantation, high PDS content improved the in vivo stability and macroscopic morphometric appearance of the tissue engineered specimens and led to enhanced deposition of glycosaminoglycans in transplanted constructs. Hydroxyproline content of the implants was not affected by either growth factors or PDS content. These data suggest a role for IGF-1 and TGFbeta-2 in preparative in vitro culture of chondrocytes before implantation, while PDS content of the scaffold is important for in vivo properties of the implanted material.
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PMID:Growth factors and scaffold composition influence properties of tissue engineered human septal cartilage implants in a murine model. 1914 66

We performed qualitative and histoquantitative investigations of tissue restoration after implanting polyglycolide (PGA), polydioxanone (PDS), polylevolactide (PLLA), and stainless steel pins in the intramedullary canal of rabbit femurs. The effect of bioabsorbable devices on healing of a cortical bone defect was also assessed. The cortical bone defect was created in the right femur of 80 rabbits. Bioabsorbable and metallic pins in 60 and two metallic pins alone were implanted in 20 intramedullary canals; 80 left femurs served as intact controls. Follow-up times were 3, 6, 12, 24, and 52 weeks. At all time points, collagenous connective tissue, including bone trabeculae, surrounded the implant at the tissue-implant interface, replacing hematopoiesis and fat of the intramedullary canal. The groups did not differ in the area and trabecular bone area fraction of the resulting callus. Residual fragments of PGA and PDS were observed at 24 weeks, and complete degradation occurred within 52 weeks. PGA, PDS, PLLA, and metallic implants induced a bony and fibrous walling-off response in the intramedullary cavity. No inflammation was observed. Complete tissue restoration did not occur within the follow-up, even after complete degradation of PGA and PDS, which had shorter degradation times than PLLA. The cortical bone healing effect was not different between bioabsorbable pins and metallic wires. Thus, these polymers had no specific osteostimulatory or osteoinhibitory properties compared to stainless steel. Within the follow-up period, there were no significant differences in biocompatibility between the implants and no adverse inflammatory foreign-body reactions.
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PMID:Tissue restoration after implantation of polyglycolide, polydioxanone, polylevolactide, and metallic pins in cortical bone: an experimental study in rabbits. 2049 91


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