Drug-Eluting Stents ; Humans ; Polymers ; chemistry ; therapeutic use ; Sirolimus ; therapeutic use

Arteriosclerosis ; drug therapy ; Coumaric Acids ; therapeutic use ; Drugs, Chinese Herbal ; therapeutic use ; Flavonoids ; Humans ; Phenols ; therapeutic use ; Phytotherapy ; Polymers ; therapeutic use ; Polyphenols ; Pyrazines ; therapeutic use

We in the present study observed the effect of N-fructose modified chitosan quaternary ammonium derivatives on on rat skin wound healing through animal experiments. Forty rats were randomly divided into eight groups (5 in each group). Four groups among the all 8 groups were the experimental groups, while the other 4 groups were the control groups. Next to the skin along the back of the spine, 1.50 cm x 2.00 cm x 0.16 cm full-thickness skin was cut to make an excision wound model for every rat. Those in the experimental groups were treated with the N-fructose-modified chitosan quaternary ammonium derivatives ointment dressing the wound, while those in the control groups with sterile medical vaseline processing. We dressed the wounds twice a day to observe the wound healing of all rats in different groups. We then observed the wound healing and wound pathology after 3, 7, 10, 15 days re spectively in different groups. Results showed significant differences of the time of wound healing, area of wound healing and volume of wound healing between the experimental groups and control groups (P < 0.05). It can be well concluded that N-fructose-modified chitosan quaternary ammonium derivatives does not harm the skin, but could promote skin healing, so that they could be suitable skin repair materials and ideal raw materials for medical dressing.
Animals ; Bandages ; Chitosan ; therapeutic use ; Polymers ; therapeutic use ; Quaternary Ammonium Compounds ; therapeutic use ; Rats ; Skin ; pathology ; Wound Healing

BACKGROUNDDrug-eluting stents represent a major advance in interventional cardiology. However, the current drug-eluting stents have significant limitations. One of the major problems is very late stent thrombosis, which is likely caused by inflammation and a hypersensitivity reaction related to a polymer on the stent. A polymer-free sirolimus-eluting stent with a unique nano-porous surface has been developed. This study aimed to evaluate this novel polymer-free sirolimus-eluting stent for its efficacy and safety in a pig model.

METHODSStents were directly coated with sirolimus (a drug concentration of 2.2 µg/mm(2) on the stent surface). The polymer-free sirolimus-eluting stents (PFSES) were compared to standard polymer-coated sirolimus-eluting stents (PCSES) and bare-metal stents (BMS) in 18 pigs.

RESULTSAt one month the degree of neointimal hyperplasia was similar between the two sirolimus-eluting stent groups and was significantly less compared to BMS ((1.93 ± 0.51) mm(2), (1.57 ± 0.69) mm(2) vs. (4.45 ± 1.05) mm(2), P < 0.05) At three months, PFSES maintained the low level of neointima ((2.41 ± 0.99) mm(2) vs. (4.32 ± 1.16) mm(2), P < 0.05), whereas PCSES had developed significant neointimal proliferation similar to BMS. The inflammation level was significantly higher in PCSES when compared with BMS three months post-implantation (2.50 ± 0.55 vs. 0.83 ± 0.75, P < 0.05) whereas PFSES showed a low level of inflammation comparable to PCSES (1.33 ± 0.52 vs. 2.50 ± 0.55, P < 0.05).

CONCLUSIONThe PFSES is effective and safe, and appears to be superior to standard PCSEs.

Animals ; Drug-Eluting Stents ; adverse effects ; Neointima ; prevention & control ; Polymers ; chemistry ; Sirolimus ; therapeutic use ; Swine

BACKGROUNDSirolimus-eluting stents (SES) are reported to be associated with reduced late lumen loss (LLL), resulting in less frequent restenosis when compared to bare-metal stent. The current study aimed to assess the difference in LLL between SES with biodegradable and with permanent polymer.

METHODSFrom March 2010 to June 2011, 300 consecutive patients having only biodegradable polymers or permanent polymer SES for all diseased vessels were included. Serial quantitative coronary analysis was performed on both the "in-stent" and "segment" area, including the stented segment, as well as both five mm margins proximal and distal to the stent. The primary endpoint was the LLL defined as the minimal lumen diameter (MLD) post-stenting minus the MLD at nine-month after the indexed procedure.

RESULTSLLL was comparable between the two stents. Importantly, LLL for the distal segment (median 0.05 mm, interquartile 0 to 0.09 mm) was less severe compared with in-stent (median 0.13 mm, interquartile 0.08 to 0.18 mm) and proximal segment LLL (median 0.12 mm, interquartile 0.06 to 0.14 mm, all P < 0.001). In general, the LLL was associated with the post-procedure MLD (b = 0.28, P = 0.002), hyperlipidemia (b = 0.14, P = 0.021), and calcified lesions (b = 0.58, P = 0.001). The R(2) and Radj of the multiple regression model were 0.651 and 0.625, respectively.

CONCLUSIONSSES with either biodegradable or permanent polymer had lower value of LLL. The small amount of LLL at the distal segment possibly contributed to the less distal edge stenosis.

Aged ; Aspirin ; therapeutic use ; Coronary Restenosis ; prevention & control ; Drug-Eluting Stents ; Female ; Humans ; Male ; Middle Aged ; Polymers ; chemistry ; Regression Analysis ; Sirolimus ; therapeutic use ; Ticlopidine ; analogs & derivatives ; therapeutic use

Aspirin ; therapeutic use ; Coronary Disease ; therapy ; Coronary Thrombosis ; chemically induced ; epidemiology ; mortality ; Drug-Eluting Stents ; adverse effects ; Humans ; Paclitaxel ; therapeutic use ; Platelet Aggregation Inhibitors ; therapeutic use ; Polymers ; chemistry ; Sirolimus ; therapeutic use ; Ticlopidine ; analogs & derivatives ; therapeutic use

OBJECTIVETo fabricate bone grafts by bone marrow stromal cell combined with modified PLGA/Type-I collagen compound scaffold using tissue engineering method.

METHODSThe modified PLGA/Type-I collagen compound scaffold was fabricated. The rabbit primary cultured osteoblasts were identified and seeded onto the modified compound scaffold for one week in vitro. The adhesion and growth of cells were observed with scanning electron microscope. The complex of cells and scaffold was implanted into the subcutaneous region of rabbits and new bone formation was evaluated.

RESULTSThe rabbit bone marrow stromal cells were induced and differentiated into osteoblasts. The adhesion and growth of osteoblasts in cluster were observed on the surface of scaffolds. New bone formation was observed at one month postoperatively and active osteoblasts were found on the surface of the newly formed bone in vivo.

CONCLUSIONThe complex of PLGA and type-I collagen is an appropriate biodegradable scaffold and can be applied in bone tissue engineering.

Absorbable Implants ; Animals ; Biocompatible Materials ; Cells, Cultured ; Collagen Type I ; therapeutic use ; Female ; Femur ; cytology ; Lactic Acid ; therapeutic use ; Male ; Osteoblasts ; cytology ; Polyglycolic Acid ; therapeutic use ; Polymers ; therapeutic use ; Prostheses and Implants ; Rabbits ; Stents ; Stromal Cells ; cytology ; transplantation ; Tissue Engineering

BACKGROUNDGuided tissue regeneration procedures provide predictable reconstruction of periodontal tissues in the treatment of furcation involvements in animals and humans. This study was to compare long-term effectiveness of two different types of polylactic acid (PLA) membranes on periodontal regeneration in surgically created class II furcation defects in dogs.

METHODSFull thickness mucoperiosteal flap was raised on the buccal aspects of the experimental teeth and class II furcation defects having 5 mm vertical dimensions were created on mandibular premolar III and IV on each quadrant. The exposed root surfaces were thoroughly planed and PLA membranes were placed over the experimental defects on both sites. One site received liquid polymer membrane (LPM), and resorbable periodontal mesh (RPM) membranes were applied to the other site. The animals were sacrificed at 7 months after surgery and the specimens were processed for histological evaluation.

RESULTSThe average length of new attachment formed on the treated roots in both groups ranged from 3.02 mm to 4.5 mm. Complete bone filling was observed at the furcation sites. No statistically significant differences were found between two membranes in any of the parameters (P > 0.05).

CONCLUSIONThis study demonstrates favorable regenerative outcomes by the use of two different types of PLA membranes that could be used as alternatives for guided tissue regeneration (GTR).

Animals ; Dogs ; Furcation Defects ; surgery ; Guided Tissue Regeneration, Periodontal ; methods ; Lactic Acid ; analogs & derivatives ; therapeutic use ; Periodontium ; physiology ; Polymers ; therapeutic use ; Wound Healing ; physiology

BACKGROUNDThe difference in clinical outcome between paclitaxal-eluting stents (PES) and sirolimus-eluting stents with bio-degradable polymer (SES-BDP) for bifurcation lesions remains unclear. The present study aimed to investigate the one-year clinical outcome after DK crush stenting using PES (Taxus(TM)) vs. SES-BDP (Excel(TM)) from our database.

METHODSA total of 275 patients (90 from the DKCRUSH-I and 185 from the DKCRUSH-II study) were studied. The primary endpoint was the occurrence of major adverse cardiac events (MACE) at 12 months; including cardiac death, myocardial infarction (MI), or target vessel revascularization (TVR). The rate of binary restenosis and stent thrombosis served as secondary endpoints.

RESULTSAt follow-up, minimal luminal diameter (MLD) in the Taxus group was (2.11 ± 0.66) mm, with resultant increased target lesion revascularization (TLR) 12.2% and TVR 14.4%, significantly different from the Excel group; (2.47 ± 0.56) mm, P < 0.001, 3.2%, P = 0.006, 4.9%, P = 0.019, respectively. As a result there was a significant difference in MACE between the Taxus (20.0%) and Excel (10.3%, P = 0.038) groups. Overall stent thrombosis was monitored in 11 patients (4.0%), with five in the Excel group (2.7%) and six in the Taxus group (6.7%). All stent thrombosis in the Excel group was classified as early, and all were defined as late in the Taxus group.

CONCLUSIONThe Excel stent had lower rate of stent thrombosis, TLR, TVR, and composite MACE at 12-month after an indexed stenting procedure, compared to the Taxus stent.

Absorbable Implants ; Aged ; Coronary Artery Disease ; therapy ; Drug-Eluting Stents ; adverse effects ; Female ; Humans ; Male ; Middle Aged ; Paclitaxel ; therapeutic use ; Polymers ; Sirolimus ; therapeutic use

This review presents the state of the art of pH-responsive polymeric micelles for cancer drug delivery. Solid tumors have a weakly acidic extracellular pH (pH < 7), and cancer cells have even more acidic pH in endosomes and lysosomes (pH 4-6). The pH-gradients in tumor can be explored for tumor targeting and drug release in cancer drug delivery by applying pH-responsive polymeric micelles. The pH-responsive polymeric micelles consist of a corona and a core, and are made of amphiphilic copolymers, in which there are pH-responsive polymeric blocks. Two types of pH-responsive polymers-protonizable polymers and acid-labile polymers have been mainly used to make pH-responsive micelles for drug delivery. The protonizable polymers are polybases or polyacids, and their water-soluble/insoluble or charge states undergo changes with the protonation or deprotonation stimulated by external acidity, while the acid-labile polymers change their physical properties by chemical reaction stimulated by the acidity. Polymeric micelles whose core or coronas respond to the tumor extracellular acidity can be explored for triggering the fast release of the carried drug, activating the targeting group and accelerating the endocytosis of drug-loaded polymeric micelles, and those whose core or coronas respond to the tumor lysosomal acidity can be used for facilitating their escape from the lysosomes and targeting the nucleus. Various in vivo and in vitro experiments demonstrated that pH-responsive polymeric micelles are effective for cellular targeting, internalization, fast drug release and nuclear localization, and hence enhancing the therapeutic efficacy and reducing the side effect of cancer chemical therapy.
Antineoplastic Agents ; administration & dosage ; therapeutic use ; Drug Delivery Systems ; Humans ; Hydrogen-Ion Concentration ; Micelles ; Nanoparticles ; Neoplasms ; drug therapy ; Polymers ; chemistry