OBJECTIVE: It has been proven that acetylsalicylic acid (aspirin), as a kind of classical non-steroidal anti-inflammatory drug, not only has the effect of anti-inflammatory, but also has the function of immunity regulation and mineralization. However, it needs further investigation to study how to delay release of aspirin for a long time and enable to promote bone regeneration. Herein, we demonstrated that the longterm delayed release pattern of aspirin through the construction of microsphere scaffolds is promising to achieve the excellent bone regeneration. METHODS: Here we synthesized three kinds of scaffolds as follows: (1) aspirin loaded calcium silicate (CaSiO₃) microsphere (CaSiO₃-aspirin) via simple immersion; (2) aspirin loaded polylactic-co-glycolic acid (PLGA) microsphere (PLGA-aspirin) via oil/water (O/W) emulsion; (3) aspirin loaded PLGA-CaSiO₃ scaffold (PLGA-CaSiO₃-aspirin) via O/W emulsion, optimal morphology and structure of PLGA-CaSiO₃-aspirin scaffold was acquired through modulating the ratio between PLGA and CaSiO₃. Furthermore, spectrophotometer was used to monitor the concentration of the extract of the three scaffolds for different releasing time, including 1, 2, 4, 6, 9, 13, 17, 21, 24, 30, 36, and 45 days, aspirin loading efficiency and its accumulation releasing curves were both achieved according to the concentration of aspirin. Their sustained release effects of aspirin were evaluated eventually. RESULTS: Environmental scanning electron microscope (ESEM) results showed that the surface structure of the three kinds of scaffolds were smooth and had uniform size distribution. In addition, a small amount of PLGA-aspirin microspheres occurred to aggregation, while a small amount of CaSiO₃-aspirin microspheres were broken. Moreover, the PLGA-aspirin microspheres in the PLGA-CaSiO₃-aspirin scaffolds were uniformly adhered to the surface of CaSiO₃ microspheres. The aspirin loadings of CaSiO₃-aspirin, PLGA-aspirin, and PLGA-CaSiO₃-aspirin were (1.06±0.04)%, (7.05±0.06)%, and (6.75±0.18)%, respectively. In addition, their corresponding time for releasing 95% of aspirin was 3, 24, and 36 days, respectively. The releasing time of PLGA-CaSiO₃-aspirin was longer than that of the others and the releasing rate was more stable. CONCLUSION The microsphere scaffold of PLGA-CaSiO₃-aspirin composites has excellent delayedrelease effect on aspirin, which is promising for using as osteogenic materials.
Aspirin ; Delayed-Action Preparations ; Lactic Acid ; Microspheres ; Polyglycolic Acid ; Polylactic Acid-Polyglycolic Acid Copolymer

PURPOSE: The purpose of this study was to evaluate the tensile strength of surgical synthetic absorbable sutures over a period of 14 days under simulated oral conditions. METHODS: Three suture materials (polyglycolic acid [PGA], polyglactin [PG] 910, and poly (glycolide-co-small je, Ukrainian-caprolactone) [PGC]) were used in 4-0 and 5-0 gauges. 210 suture samples (35 of each material and gauge) were used. All of the samples were tested preimmersion and 1 hour and 1, 3, 7, 10, and 14 days postimmersion. The tensile strength of each suture material and gauge was assessed. The point of breakage and the resorption pattern of the sutures were also assessed. RESULTS: During the first 24 hours of immersion, all 4-0 and 5-0 samples of PGA, PG 910, and PGC maintained their initial tensile strength. At baseline (preimmersion), there was a statistically significant (P<0.001) difference in the tensile strengths between the 4-0 and 5-0 gauge of PGA, PG 910, and PGC. PGA 4-0 showed the highest tensile strength until day 10. At 7 days, all the 4-0 sutures of the three materials had maintained their tensile strength with PGA 4-0 having significantly greater (P=0.003) tensile strength compared to PG. CONCLUSIONS: 4-0 sutures are stronger and have greater tensile strength than 5-0 sutures. The PGA 4-0 suture showed the highest tensile strength at the end of day 10.
Immersion ; Polyglactin 910 ; Polyglycolic Acid ; Prostaglandins A ; Sutures ; Tensile Strength

PURPOSE: To evaluate the usefulness and safety of unified technique of vascular control before renal exposure in reconstructive surgery of renal trauma. MATERIALS AND METHODS: From July 1995 to June 1997, 10 patients with major renal trauma who operated by unified approach technique were included in this study. Blunt trauma was the mechanism of injury in 8 patients and 2 were resulted from penetrating(stab) injury. Of the injuries 2 were grade 3, 7 grade 4, 1 grade 5. RESULTS: Of the 10 patients, 8(80%) were performed kidney preserving surgery and 2(20%) resulted in nephrectomy. Partial nephrectomy was underwent in 6 patients(with vascular repair in 2 cases) and renorrhaphy in 2 patients. Pedicle flap of omentum was used mainly and polyglycolic acid mesh also used in 2 cases as coverage material of parenchymal defect. Complications occurred in 2 cases(20%) but none resulted in renal loss with the mean followup of 10 months(1 to 15 months). CONCLUSIONS: Unified approach technique of vascular control before renal exposure seems to be a safe and effective method for reconstructive surgery in renal trauma. To confirm this result, studies with more cases and longer followup are needed.
Follow-Up Studies ; Humans ; Kidney* ; Nephrectomy ; Omentum ; Polyglycolic Acid

PURPOSE: The objective of the present study was to histologically evaluate durability and bone regeneration capacity of new synthetic membranes in comparison to clinically available collagen membrane. MATERIAL AND METHODS: To the skulls of 12 rabbits, we created 4 bone defects of 6 mm in diameter on each of them. Each of defects were covered with at least one of 5 membranes: No membrane, Collagen (Ossix(TM)), PLGA, HA-coated-PLGA and HA-PLGA/PLGA. After 4, 8, 12 weeks, we cut the skulls and dyed with H-E. And then, the histologic observation was done. RESULTS: In current study, the control group which did not use the membrane showed bone regeneration at 12 weeks and covered the bone defect partially. New bones were formed through the underneath of endocranium, and the upper defect was filled with connective tissues and fats. Collagen membrane (Ossix(TM)) showed new bones after 4 weeks, and they were formed through the membrane which maintained until 12 weeks. PLGA, HA-coated-PLGA, HA-PLGA/PLGA showed bone regeneration after 4 weeks and after 8 weeks, they mostly filled defects. At 12 weeks, we could find new bones and previous bones almost look alike and also, they united well. Membranes were unnoticeable after 4 weeks and were absorbed. CONCLUSION: Bone formation and maturation of PLGA, HA-coated-PLGA and HA-PLGA/PLGA were faster than the control group. They showed no difference on the application of HA and after 4 weeks, they were absorbed.
Bone Regeneration ; Collagen ; Connective Tissue ; Fats ; Hyaluronic Acid ; Lactic Acid ; Membranes ; Osteogenesis ; Polyglycolic Acid ; Rabbits ; Skull

OBJECTIVE: To construct a biodegradable PLGA nerve conduit (NC) filled with NSCs in order to improve facial nerve regeneration. METHOD: SD rats were subjected to right facial nerve transection, and PLGA NCs filled with NSCs were used to bridge the nerve gap. Facial nerve regeneration was assessed 4 and 12 weeks after surgery, through electrophysiological testing, and morphometric analysis of axons. RESULT: Nerve action potential amplitude, and axonal area were significantly greater in the NSCs group than the empty NC group. CONCLUSION NSCs transplantation may improve regeneration of the facial nerve.
Animals ; Facial Nerve Injuries ; surgery ; Female ; Lactic Acid ; Nerve Regeneration ; Neural Stem Cells ; transplantation ; Polyglycolic Acid ; Polylactic Acid-Polyglycolic Acid Copolymer ; Pregnancy ; Rats ; Rats, Sprague-Dawley

PURPOSE: This study was conducted to identify the surface characteristics of titanium discs coated with MS275/PLGA by electrospray and which is effective to mesenchymal stem cell proliferation. MATERIALS AND METHODS: We used anodized surface coated with PLGA as a control group and anodized surface coated with MS275 0.5 microM, 1 microM, 1.5 microM as test groups. To examine that the coating particles are nanometer sized, FE-SEM was used and AFM was utilized to determine the difference of coating surface roughness. We checked the mesenchymal stem cell proliferation by using MTT assay on 1st, 4th, 7th days. RESULTS: There was no significant difference between control groups and test groups in AFM results (P>.05). In MTT assay results, mesenchymal stem cell proliferation was increased with time, at 7th day, cell viability on discs coated with 1.5 microM MS275 was significantly higher than control group (P<.05). As SEM showed, the number of cells on all discs was increased and the morphology of cell attachment was also wider and closer with time. CONCLUSION: Titanium surface coated with MS275/PLGA showed significantly higher cell proliferation and the more density of MS275 was dispersed on titanium discs, the faster cells grew.
Cell Proliferation ; Cell Survival ; Lactic Acid ; Mesenchymal Stromal Cells ; Polyglycolic Acid ; Titanium

PURPOSE: This study was designed to compare the bond regeneratiom effects of treatment using silk fibroin membrane ( Nanogide-S (R)) resorbable barrier with control group treated by polyactic acid / polylacticglycolic acid membrane(Biomesh (R) ) METHODS:44 severe bone loss on extraction socket from 44 patients were used in this study. In experimental group 22 sites of them were treated by silk fibrin membrane as and the other 22 sites were treated by polyactic acid/ polylacticglycolic acid membrane as a control group. Clinical parameters including recovered bone width, length and radiographic parameter of vertical length were evlauated at base line and 3 months after surgery. RESULTS: 1) Severe bone width, length was significantlly decreased in two group. 2) Bone width, length was significantlly decreased in two group. 3) Decreased bone width, length and radiographic examination differences between group. CONCLUSIONS: On the basis of these results, silk fibrin resorbable membrane has similar bone regeneration ability to polyactic acid / polylacticglycolic acid membrane in guided bone regeneration for severe bone loss defect on extraction socket.
Bone Regeneration ; Fibrin ; Fibroins ; Humans ; Lactic Acid ; Membranes ; Polyglycolic Acid ; Regeneration ; Silk

STATEMENT OF PROBLEM: A biochemical approach for surface modification has offered an alternative for physicochemical and morphological methods to obtain desirable bone-implant interfaces. PURPOSE: The purpose of the present study was to investigate cell responses to poly (D,L-lactide-co-glycolide) (PLGA)/1alpha, 25-(OH)2D3 coating with reference to cellular proliferation and differentiation in vitro. MATERIAL AND METHODS: 96 titanium discs were fabricated and divided into four groups. Group 1 was anodized under 300 V as control. Group 2, 3 and 4 were anodized then coated with 3 ml PLGA/1alpha, 25-(OH)2D3 solutions. Amount of the solutions were 2 ul, 20 ul and 200ul respectively. The osteoblast-like Human Osteogenic Sarcoma (HOS) cells were seeded and cultured for 1, 3 and 7 days. MTSbased cell proliferation assay and ALPase activity test were carried out. RESULTS: PLGA nanoparticles were observed as fine, smooth and round and HOS cells attached to the anodized surfaces through strand-like and sheet-like filopodia. After 3 days of culture, the dendritic filopodia were exaggerated and sheet-like cytoplasmic projections covered the coated titanium surfaces. After 3 days of culture, all of the groups showed increased cellular proliferation and the lowest proliferation rate was measured on group 2. Higher amount of incorporated 1 alpha, 25-(OH)2D3 (Group 3 and 4) improved cellular proliferation but the differences were not significant statistically (P > .05). But they increased the rate of ALP activities than the control group at day 3 (P < .05). CONCLUSION: Biodegradable PLGA nanoparticles incorporated with vitamin D metabolite positively affected proliferation and differentiation of cells on the anodized titanium surface.
Calcitriol ; Cell Proliferation ; Cytoplasm ; Humans ; Lactic Acid ; Nanoparticles ; Osteosarcoma ; Polyglycolic Acid ; Pseudopodia ; Seeds ; Titanium ; Vitamin D

This research was aimed to develop the technique and formula for the preparation of stable and effective microbubbles containing hydrophilic drugs. We prepared EB-PLGA microbubbles and evaluated its drug loading and burst release to choose the best technique and formula. The result of optimizing formula was W1/O (1:15), EB-PLGA (0.04), PVA (5%). The burst release decreased after the addition of supplemental agent and the change of method for preparation. We concluded that the optimizing formula could elevate drug loading and decrease burst release obviously.
Drug Carriers ; chemistry ; Lactic Acid ; chemical synthesis ; chemistry ; Microbubbles ; Polyglycolic Acid ; chemical synthesis ; chemistry ; Quality Control

OBJECTIVETo elongate human nerve axon in culture and search for suitable support matrices for peripheral nervous system transplantation.

METHODSHuman embryo cortical neuronal cells, seeded on poly (D,L-lactide-co-glycolide) (PLGA) membrane scaffolds, were elongated with a self-made neuro-axon extending device. The growth and morphological changes of neuron axons were observed to measure axolemmal permeability after elongation. Neurofilament protein was stained by immunohistochemical technique.

RESULTSHuman embryo neuron axon could be elongated and cultured on the PLGA membrane and retain their normal form and function.

CONCLUSIONSThree dimensional scaffolds with elongated neuron axon have the basic characteristics of artificial nerves, indicating a fundemental theory of nerve repair with elongated neuron axon.

Axons ; drug effects ; transplantation ; Coculture Techniques ; Humans ; Immunohistochemistry ; Lactic Acid ; Polyglycolic Acid ; Polymers ; Tissue Engineering ; methods