Accumulation of poly(3-hydroxybutyrate) [poly(3HB)] by V. natriegens was studied. Results indicated that V. natriegens used glucose, gluconate, fructose and molasses as carbon sources for poly(3HB) synthesis. When molasses was used, up to 28.4% of poly(3HB) to cellular dry weight was accumulated. The accumulation of poly(3HB) followed, was not simultaneously to, the cell growth. Analysis of the PHA polymerase, beta-ketothiolase, and acetoacetyl-CoA reductase showed that the poly(3HB) accumulation was correlated to the increase of their activities in cells. Poly(3HB) accumulation was also related to the de novo fatty acid synthesis, as revealed by the results that cerulenin, a specific inhibitor to the de novo fatty acid synthesis, significantly reduced accumulation of poly(3HB). Based on the results from this study, the synthetic pathway of poly(3HB) was proposed.
Cerulenin ; pharmacology ; Hydroxybutyrates ; metabolism ; Polyesters ; metabolism ; Vibrio ; metabolism

PUE@PEG-PLGA micelles has excellent characteristics such as small particle size, high drug loading and slow drug release. The results of TEM electron microscopy showed that PUE@PEG-PLGA micelles had obvious core-shell structure. The critical micelle concentration(CMC) of PEG-PLGA micelles determined by pyrene assay was about 4.8 mg·L~(-1). Laser confocal experiments showed that PEG-PLGA micelles can enhance the cellular uptake of coumarin-6 and aggregate around the mitochondria; quantitative results of extracellular drug residues also indirectly confirmed that PEG-PLGA micelles can promote cellular uptake of the drug. Acute ischemic myocardial model rats were prepared by coronary artery ligation, and then the model rats were randomly divided into six groups: Sham operation group, model group, puerarin(PUE) group, as well as low-, mid-, and high-dose PUE@PEG-PLGA micelles groups. Drugs were given by iv administration 5 min after the ligation. The ST segment changes in the electrocardiogram were monitored; serum creatine kinase(CK), lactate dehydrogenase(LDH), aspartate aminotransferase(AST), and malondialdehyde(MDA) levels were detected and myocardial infarct size was also measured. Both PUE and PUE@PEG-PLGA micelles can reduce the elevated ST segment, reduce serum CK, LDH, AST and MDA levels, and reduce myocardial infarct size. The efficacy of PUE@PEG-PLGA medium and high dose groups was significantly better than that in the PUE group, and the efficacy in PUE@PEG-PLGA low dose group was basically equivalent to that in the PUE group. PUE@PEG-PLGA micelles can greatly improve the cardiomyocytes uptake of PUE, enhance the anti-acute myocardial ischemia effect of drugs, and reduce its dosage.
Animals ; Isoflavones ; pharmacology ; Micelles ; Myocardial Ischemia ; drug therapy ; Polyesters ; Polyethylene Glycols ; Random Allocation ; Rats

Poly(epsilon-caprolactone) microspheres were fabricated with an average particle size of 5.08 +/- 0.23 microns. The effect of poly(epsilon-caprolactone) microspheres on apoptosis and cell cycle of fibroblast was studied with flow cytometry. The data obtained clearly indicated that poly(epsilon-caprolactone) microspheres purified in different ways showed different cytocompatibility. The well purified microspheres have good cytocompatibility.
Animals ; Biocompatible Materials ; chemical synthesis ; pharmacology ; Biodegradation, Environmental ; In Vitro Techniques ; Materials Testing ; Mice ; Microspheres ; Polyesters ; chemical synthesis ; pharmacology

Lamellar particles(lamellae) were prepared by non-solvent precipitation from crystalic poly-L-lactic acid (PLLA). The PLLA lamellae exhibite a diamond or stepped irregular shape with a size range between 3-5 microns. Prepared without any surfactants and dispersing agents, the lamellar particles have clean surface, which is advantageous for the adsorption of proteins. The PLLA lamellar particles adsorbed protein cytokine interferon-alpha (IFN-alpha) with an adsorption efficiency of > or = 95%. The release of loaded IFN could continue for more than 10 days. The cell incubation experiments showed that the PLLA lamellar particles were easy to be phagocytosed by macrophages. The immunological experiments showed that the biological activity of IFN-alpha loaded on the PLLA lamellar particle was effectively retained.
Adsorption ; Chemistry, Pharmaceutical ; Drug Carriers ; Interferon-alpha ; chemistry ; pharmacology ; Lactic Acid ; chemistry ; Particle Size ; Polyesters ; Polymers ; chemistry

OBJECTIVETo prepare cisPLLAtin-loaded polylactic acid/cnts, and to study the anti-tumor effect of 5-FU-PLLA-CNTs on human gastric carcinoma cell lines(MGC803 and MNK45).

METHODS5-FU-PLLA-CNTs were prepared with ultrasound emulsification. The morphology of 5-FU-PLLA-CNTs was determined by scanning electron microscope(SEM), and its drug loading and drug release curve in vitro were detected by UV-Vis-NIR spectrophotometer. Cells were divided into experiment, positive control and negative control groups. CCK8 method was used to test the cytotoxic effect of 5-FU-PLLA-CNTs in different concentrations on MGC803 and MNK45 cell proliferation. Flow cytometry was employed to measure the apoptotic rate of MGC803 and MNK45 cells before and after the intervention of 5-FU-PLLA-CNTs.

RESULTSDeep layer film of 5-FU-PLLA-CNTs was successfully established, whose drug-load rate was(4.54±0.43)%, entrapment rate was(21.56±2.36)%. In vitro release test showed release rate within 24 h of 5-FU-PLLA-CNTs was 23.9% in a as lowly increasing manner, and accumulating release rate was 85.3% at day 31. CCk8 experiment revealed, as compared to control group, 5-FU-PLLA-CNTs significantly inhibited the proliferation of two cell lines in dose-dependent and time-dependent manner. The best 5-FU-PLLA-CNTs concentration of inhibition for human gastric cancer cell lines was 1 mg/well. Flow cytometry indicated the apoptotic rate of MGC803 and MNK45 cells in experiment group treated by 1 mg/well 5-FU-PLLA-CNTs significantly increased as compared to negative control group (P<0.05), while the difference was not significant as compared to positive control group (P>0.05).

CONCLUSIONThe 5-FU-PLLA-CNTs has good drug sustained-release capacity, and can significantly kill and inhibit the proliferation of MGC803 and MNK45 cell lines.

Cell Line, Tumor ; Cell Proliferation ; drug effects ; Delayed-Action Preparations ; Fluorouracil ; pharmacology ; Humans ; Lactic Acid ; pharmacology ; Nanotubes, Carbon ; Polyesters ; Polymers ; pharmacology ; Stomach Neoplasms ; pathology

OBJECTIVETo study the ectopic osteogenesis of tissue engineered bone with recombinant human bone morphogenetic protein/transforming growth factor-beta (rhBMP/TGF-beta) or WO-1 slow-released factors.

METHODSPartial demineralized freeze-dried bone (PDFDB) of pig was used as scaffold material. rhBMP/TGF-beta or WO-1 were pre-coated on the surface of material by means of vacuum negative pressure absorption, and then coated with polylactic acid (PLA) to make slow-released material. There were six group: PDFDB material (group A); PDFDB combined with osteoblasts (group B); PDFDB material with rhBMP/TGF-beta slow-released system (group C); PDFDB material combined with rhBMP/TGF-beta slow-released system osteoblasts (group D); PDFDB with WO-1 slow-released system (group E); PDFDB material combined with WO-1 slow-released system and osteoblasts (group F) were implanted in bilateral lower limbs of 36 Newzealand rabbits respectively (6 rabbits in each groups). Histological, histochemical and biochemical analysis were detected 2, 4, 6, 8 weeks after operation.

RESULTSWithin the observation periods, no osteogenesis was observed in group A. The osteogenesis in group B, D, F were superior to that of group C and E (P < 0.05). The osteogenetic activity in group C and E was delayed. The quantity and quality of osteogenesis in group D and F were 2 weeks ahead of time compared with group B, and 4 weeks to that of group C and E. The newborn calcification content was superior to that of group A, C, and E (P < 0.05).

CONCLUSIONSThe osteogenesis of PDFDB materials with BMP/TGF-beta or WO-1 is slower than that of which combined with osteoblasts. Simple material PDFDB has no ectopic osteogenesis.

Animals ; Bone Morphogenetic Proteins ; pharmacology ; Bone Substitutes ; pharmacology ; Child ; Drug Synergism ; Female ; Humans ; Lactic Acid ; pharmacology ; Osteogenesis ; drug effects ; Polyesters ; Polymers ; pharmacology ; Rabbits ; Recombinant Proteins ; pharmacology ; Swine ; Tissue Engineering ; Transforming Growth Factor beta ; pharmacology

Two new polyesters, talapolyesters G-H (1-2) were isolated from the wetland soil-derived fungus Talaromyces flavus BYD07-13, and their structures were determined by NMR and MS spectroscopic data. The absolute configurations of the residues were determined by alkaline hydrolysis. The cytotoxicity against five tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480) of 1-2 was examined.
Cell Line, Tumor ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; pharmacology ; Humans ; Molecular Structure ; Polyesters ; chemistry ; isolation & purification ; pharmacology ; Talaromyces ; chemistry ; growth & development ; Wetlands

OBJECTIVETo determine the efficacy of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits.

METHODSTwenty-four Japanese white rabbits underwent laminectomy (including the attached ligaments) at L(2 ) and L(5). After laminectomy at L(5), polylactic acid glue was sprayed on the dura and nerve roots and this segment was taken as the experimental group. After laminectomy at L(2), nothing was used and this segment was enrolled as the self control group. Four rabbits were killed every two weeks postoperatively till the end of the experiment at 12 weeks. Then the operated spine was observed grossly, histologically and ultrastructurally to check the degree of scar formation, the status of epidural scar adhesion, the absorption of the glue, and the intracellular structure of fibroblasts.

RESULTSThe glue coagulated immediately after spraying and showed excellent hemostatic effect. The glue membrane was easy to be taken away from the dura mater of the samples for 2 weeks and there were no cells in the epidural space in the experimental group. But the dura mater was covered by hematoma in the control group, which formed mild adhesion, with fibroblasts proliferating actively. In the 4th week, some glue shivers remained in the epidural space with fibroblasts increasing a little, and the dura mater was smooth in the experimental group. However, in the control group, the formed scar was fragile and conglutinated with the dura mater diffusely and fibroblasts were much more than those in the experimental group. In the 6th-12th weeks, there was a potential interspace between the scar and the dura mater, and the polylactic acid glue was absorbed completely in the experimental group. Much tough scar was found in the control group, which was very difficult to dissect from the dura mater and the surrounding tissues. From the ultrastructural observation of the fibroblasts, the nucleus became much bigger and the rough endoplasmic reticulum was much more plentiful in the control group than that in the experimental group.

CONCLUSIONSPolylactic acid glue can effectively reduce epidural cicatrization and adhesion.

Animals ; Biocompatible Materials ; Cicatrix ; prevention & control ; Lactic Acid ; administration & dosage ; pharmacology ; Laminectomy ; Membranes, Artificial ; Polyesters ; Polymers ; administration & dosage ; pharmacology ; Postoperative Complications ; prevention & control ; Rabbits ; Tissue Adhesions ; prevention & control

Biocompatibility of a newly developed ethylenediamine modified poly (DL-latic acid) (EMPLA) with osteoblasts was investigated by means of cell morphology and cell proliferation. Films of PLA and EMPLA were made by solvent casting. Osteoblasts obtained from crania of neonatal Wistar rats were cultured on surfaces of PLA and EMPLA, with glass as control. The cell morphology was observed by phase contrast microscope and the cell proliferation was determined by MTT assay. The morphology observations revealed that the osteoblasts cultured on EMPLA spread wider than those on PLA, and much more cells were confluent on EMPLA, compared to those on PLA and glass. The growth curves showed the osteoblasts on EMPLA grew faster than did those on PLA and glass. The results exhibited that the biocompatibility of EMPLA with osteoblasts is better than that of PLA and glass, which suggested wide applications of EMPLA in biomedical area, especially in tissue engineering.
Animals ; Animals, Newborn ; Biocompatible Materials ; chemistry ; pharmacology ; Cell Proliferation ; Cells, Cultured ; Ethylenediamines ; chemistry ; pharmacology ; Lactic Acid ; chemistry ; pharmacology ; Materials Testing ; methods ; Osteoblasts ; cytology ; Polyesters ; Polymers ; chemistry ; pharmacology ; Rats ; Rats, Wistar

OBJECTIVETo evaluate the cytotoxicity of polylactic acid-chitin plates in vitro.

METHODSThe cytotoxicity of polylactic acid-chitin plates was evaluated with MTT assay and direct contact assay using the cell line L929 in vitro. L929 cells were cultured with different concentrations of the extracts of polylactic acid-chitin plates (0, 50% and 100%, V/V) in vitro, and MTT assay was performed to evaluate the cell proliferation at 2, 4 and 7 days. The morphologic changes of the cells were observed by inverted microscope and scanning electron microscope.

RESULTSMTT assay revealed that the extracts of polylactic acid-chitin plates enhanced the cell proliferation (P<0.01), but not in a dose-dependent manner (P>0.05). In the direct contact assay, no side effects were found in regard to the cell growth, proliferation and attachment to the polylactic acid-chitin plates as compared with the negative control. The cytotoxicity grade of polylactic acid-chitin plates was 0 or 1, suggesting that the material was almost free of cytotoxicity.

CONCLUSIONThe polylactic acid-chitin plate possesses ideal cellular compatibility, and therefore has great potential for clinical use as an internal bone fixation material.

Animals ; Biocompatible Materials ; pharmacology ; Cell Line ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Chitin ; pharmacology ; Fibroblasts ; cytology ; ultrastructure ; Fracture Fixation, Internal ; instrumentation ; Lactic Acid ; pharmacology ; Materials Testing ; Microscopy, Electron, Scanning ; Polyesters ; Polymers ; pharmacology ; Time Factors