Biomedical subjects

Yong-jie Zhang

Publications and source records attributed to Yong-jie Zhang.

8 recordsLinked to original sources

PubMed2005

Release of bioactive BMP from dextran-derived microspheres: a novel delivery concept.

Recent developments of biotechnology have produced a great variety of protein and bioactive drugs. For these drugs to be used therapeutically, suitable drug delivery systems have become increasingly essential. Dextran-derived biomaterials have been considered to be compatible matrices for protein and bioactive drugs because of their hydrophilic properties and ability to control drug dissolution and permeability. A novel class of dextran-glycidylmethacrylate (Dex-GMA)/poly(ethylene glycol) (PEG) microspheres were designed and synthesized by polymerization of Dex-GMA emulsified in an aqueous PEG solution. Dex-GMA was prepared by substituting the hydroxyl groups in Dex by GMA. The drug loading and in vitro drug release was evaluated by routine procedure and the biological activity of BMP-loaded microspheres was studied by experimental cytology methods. Recombinant human bone morphogenetic protein-2 (rhBMP-2) were entrapped in dextran-derived microspheres quantitatively and with full preservation of their biological activity. In vitro release kinetics indicated that dextran-derived microspheres could retain rhBMP-2 in a variable manner depending on the preparation and degradation of the microspheres. The release profiles of rhBMP-2 from microspheres as a function of time showed that rhBMP-2 releasing kinetics in vitro fitted to first-order and Higuchi equations. The release profile in vitro was in accord with two phases kinetics law and more than 60% drug were released during 20 days. Cytology studies showed rhBMP-2 microspheres have good biological effects on cultured periodontal ligament cells, and could achieve a longer action time than concentration of rhBMP-2 solution. These properties make those microspheres interesting osteo-conductive BMP carriers, allowing to decrease the amount of implanted factor required for tissue regeneration.

Alkaline Phosphatase↗

PubMed2005

[Analysis of the relation between surgery and prognosis of hilar cholangiocarcinoma].

OBJECTIVE: To explore the prognosis factors of hilar cholangiocarcinoma, and investigate the relation between operative procedure and prognosis of it. METHODS: A retrospective cohort study was investigated in 198 patients with hilar cholangiocarcinoma, who were treated in our hospital from December 1997 to December 2002. There were 117 males and 81 females. The age ranged from 27 to 81 years old with a mean of 56. Jaundice (94.5%), pruritus (56.6%) and abdominal pain (33.8%) were the main present symptoms. According to Bismuth-Corlette classification, there were 14 type I cases, 19 type II cases, 12 type IIIa cases, 15 type IIIb cases, 112 type IV cases and 26 unclassifiable cases. One hundred and forty four cases received open operative treatment, and the others only were treated with endoscopic approach (including ERBD or EMBE 21 cases, ENBD 31 cases) or percutaneous transhepatic cholangiodrainage (2 cases). Tumor resection was performed on 120 cases with a resection rate of 83.3%, included radical resection 59 cases (41.0%). Twenty-four cases underwent paunched biliary exploration and drainage. RESULTS: The Cox's regression model analysis showed that occupation, preoperative maximum total serum bilirubin level, operative procedure and postoperative adjuvant radiation affected postoperative survival significantly, but gender, age, choledocholithiasis, hepatitis, preoperative serum CA19-9 level, Bismuth-Corlette type, histopathologic grading and postoperative chemotherapy were not significant prognostic factors. The postoperative survival of biliary drainage group, palliative resection group and radical resection group, which statistically differed pairwise. Between ERBD or EMBE group and palliative resection group, there was no statistical difference. So was between ERBD or EMBE group and biliary drainage group, or between ENBD group and biliary drainage group. The survival differed statistically between ERBD or EMBE group and ENBD group. CONCLUSIONS: Operative procedure was the most important prognosic factor of hilar cholangiocarcinoma, radical resection still was the primary measure to cure and long term survival. For irresectable hilar cholangiocarcinoma, the effect of ERBD or EMBE could not be considered to be worse than that of open operative treatment.

Adult↗

PubMed2005

Preparation of recombinant human bone morphogenetic protein-2 loaded dextran-based microspheres and their characteristics.

AIM: To prepare new pharmaceutical forms with sustained delivery properties of recombinant human bone morphogenetic protein-2 (rhBMP2) for tissue engineering and guided tissue regeneration (GTR) use. METHODS: rhBMP2-loaded dextran-based hydrogel microspheres (rhBMP2-MPs), which aimed to keep rhBMP2 bioactivity and to achieve long-term sustained release of rhBMP2, were prepared by double-phase emulsified condensation polymerization. The physical, chemical performances and biological characteristics of those microspheres were studied both in vitro and in vivo. RESULTS: The microspheres' average diameter was 30.33+/-4.32 microm with 75.4% ranging from 20 microm to 40 microm and the drug loading and encapsulation efficiency were 7.82% and 82.25%, respectively. The rhBMP2-releasing profiles in vitro showed that rhBMP2 release could be maintained more than 10 d. The rhBMP2-MPs, with good swelling and biodegradation behavior, could be kept for 6 months at below 4 degree without significant characteristic change or bioactivity loss. Cytology studies showed that rhBMP2-MPs could promote the proliferation of periodontal ligament cells (PDLCs) approximately 10 d, while the bioactivity of concentrated rhBMP2 solution could keep no more than 3 d. Scanning electron microscope showed that rhBMP2-MPs could be enchased into the porous structure of calcium phosphate ceremic (CPC) and the eugonic growth of PDLCs in CPC/rhBMP2-MPs scaffolds. Animal experiments indicated that using CPC/rhBMP2-MPs scaffolds could gain more periodontal tissue regeneration than using rhBMP2 compound firsthand with CPC (CPC/rhBMP2). CONCLUSION: By encapsulating rhBMP2 into dextran-based microspheres, a small quantity of rhBMP2 could achieve equivalent effects to the concentrated rhBMP2 solution and at the same time, could prolong rhBMP2 retention both in vitro and in vivo.

Animals↗

PubMed2005

[Modified intranasal endoscopic Lothrop procedure].

OBJECTIVE: To report the experience of modified endoscopic Lothrop procedure (MELP) in 6 cases and to discuss the operative technique and indications. METHODS: Six patients (four males and 2 females) aged from 6 to 63 years old with frontal sinus diseases were enrolled in this study, including 3 cases of frontal mucocele, 1 case of recurrent hemangioma, 1 case of recurrent inverted papilloma and 1 case of osteoma. All patients were underwent intranasal modified Lothrop procedure with the guidance of nasal endoscope. The image-guided navigational system was used for the location of frontal sinus in 2 cases. RESULTS: The operation was successful in all 6 patients without any operative and postoperative complications. The average operation time was 3.2 h. The endoscopic examination demonstrated the wide communicational frontal sinus openings and well epithelization after 6-40 months follow-up. The patients were asymptomatic up to now and no recurrence was found. CONCLUSIONS: The modified intranasal endoscopic Lothrop procedure is an ideal surgical approach for recalcitrant frontal sinus disorders on the basis of proper selection of surgical equipments and patients by the experienced surgeon.

Adolescent↗

PubMed2005

[Endoscopic surgery for nasal septal perforation].

OBJECTIVE: To describe the relevant factors of endoscopic surgery in patients with nasal septal perforation. METHODS: Twenty-three patients with nasal septal perforation were treated under nasal endoscope. Four kinds of reconstruction materials were used to accomplish the closure of perforation: residual osseous septum or temporalis fascia, inverting septal mucoperichondrial flap, autologous connective tissue insert overlaid with mucous flaps and turbinate flap. The reconstructed septum was packed by moist dressing with silicone or plastic splints. RESULTS: Seven patients underwent direct closure. Inverting flap repair for five cases, shifting flap closure for ten cases, and repair with turbinate flap in one case. During the follow-up ranging from four weeks to seven months, the successful reconstruction was achieved in 19 cases (82.6%). The problems in the remaining four cases were: mucosal flap displacement, fascia flap shrank and so caused reperforation, two perforations present with only the larger one repaired, the mucosal flap was smaller in size than the perforation. CONCLUSIONS: Intranasal endoscopic reconstruction surgery is a reasonable management for nasal septal perforation.

Endoscopy↗

PubMed2004

[Prognostic analysis of patients suffering from distal bile duct cancer].

OBJECTIVE: To study prognostic factors after surgical procedure for distal bile duct cancer. METHODS: A retrospective clinical analysis was made in 173 cases of distal bile duct cancer, admitted to our hospital from February 1996 to December 2002. Fourteen clinicopathologic factors that could possibly influence survival were selected. A multivariate analysis of these individuals was performed using the Cox Proportional Hazards Model. RESULTS: There were 99 males and 74 females. The age ranged from 27 to 74 years old with a mean of 55.5. Radical resection was performed on 152 cases with radical resection rate of 87.9%. 29 cases died of liver metastasis with a rate of 46.8% in total death cases. The statistical analysis showed that surgical procedure, lymph node metastasis and pathological differentiation grade affected postoperative survival significantly, but transfusion, invasion of pancreas, postoperative radiotherapy and chemotherapy, ERCP, diameter of tumour, serum level of CA-19-9, preoperative total serum bilirubin level (TBIL), ratio of albumin to globulin (A/G), sex and age are not significant factors influencing postoperative survival. CONCLUSIONS: Radical resection is only curative treatment modality. Aggressive treatment and prevention on postoperative liver metastasis is a important strategy to improve the survival for distal bile duct cancer.

Adult↗

PubMed2004

[Imaging-navigated endoscopic sinus surgery].

OBJECTIVE: To evaluate the advantages and disadvantages of different type of image-guidance system in endoscopic sinus surgery. METHODS: Fifty-three endoscopic sinus surgery were performed under different type of image-guidance system, there were 24 chronic sinusitis with or without nasal polyp, 4 juvenile nasopharyngeal angiofibroma, 8 pituitary adenoma, 9 ethmoid ossifying fibroma, 2 nasopharyngeal mixed tumor, 1 nasal leiomyoma, 3 fungal sinusitis, and 2 inverting papilloma. RESULTS: In all cases, the preoperative time was 15-30 minutes, the registration rate were 1.3-2.0, the localization accuracy was within 1 mm. Compared with the traditional endoscopic sinus surgery, the operating time was similar, without obvious difference. No complication occurred. CONCLUSION: All types of image-guidance system could work well with endoscopic system, each of them had its own shortages. Every type of image-guidance system could identify the borders and critical anatomical structures in the corresponding CT data, especially in cases in which anatomical landmarks were no longer present, with anatomical variation, intranasal and anterior skull base tumor. Combined with endoscopic surgery, the image-guided endoscopic surgery provided accurate tumor resection while preserving normal tissue, increased surgical effectiveness, decreased overall surgical complications. It is believed that the image-guidance system is a useful tool for endoscopic sinus surgery.

Adolescent↗

PubMed2003

[Long-term outcomes and analysis of its relative factors of nasal endoscopic sinus surgery in children].

OBJECTIVE: To evaluate the results of endoscopic sinus surgery (ESS) in children with chronic sinusitis. The long-term outcomes and the relative factors were analyzed retrospectively. MATERIALS AND METHODS: A total of 268 children (432 sides), 186 males and 82 females, aged 3 to 17 years (average, 14.3) were included in this study (underwent ESS). The postoperative follow-up time of 188 cases (305 sides, 70.1%) was over one year. The management during follow-up was adopted under nasal endoscope and local anesthesia. The postoperative treatment included cleaning operative cavity, nasal irrigation, antibiotics, steroid, immune regulator, etc. RESULTS: Overall cases included 89 cases (147 sides) of chronic sinusitis, 86 cases (142 sides) of nasal polyps and 13 cases (16 sides) of mucocele respectively. The cure rate was 70.2% (132 cases). 43 cases (22.9%) were improved, while other 13 cases were of no effect. Overall symptoms, 93.1% children with headache were improved, 85.1% children were free of nasal obstruction and 60.1% children gained a relief of purulent discharge. 11 cases had no change and 2 cases were worse compared with before surgery. 34 cases with anosmia were improved or recovered after ESS. The total effective rate of ESS was 93.1%. 8 cases received a revision ESS. CONCLUSIONS: ESS in children with chronic sinusitis and polyps has a good long-term outcomes. The reasonable reservation of mucosa during ESS must be emphasized. The quality of follow-up is an important factor affecting the results of ESS. Whether the disciplinary preoperative management was made or not is the hypothesis of ESS indications.

Adolescent↗