Objective To demonstrate the importance of bioreactor to tissue engineering and to disscuss the direction of bioreactor- researching. Methods Alarge quantity of literature was reviewed, analyzed and summarized. Results Bioreactor has greatly promoted the progress of tissue engineering in heoretics and practice,and has become one of the most important parts of tissue engineering. Conclusion Bioreactor is indispensable for tissue engineering,and it should be developed along integration,automation and intelligentificaton.Its application should run through the whole process of tissue engineering.
OBJECTIVE: To observe the effect of engineered epiphyseal cartilage regenerated in vitro with 3-D scaffold by chondrocytes from epiphyseal plate in repairing the tibial epiphyseal defect, and to explore the methods to promote the confluence between engineered cartilage and epiphyseal plate. METHODS: Chondrocytes were isolated enzymatically from the epiphyseal plates of immature rabbits, and then planted into the tissue culture flasks and cultivated. The first passage chondrocytes were collected and mixed fully with the self-made liquid biological gel at approximately 2.5 x 10(7) cells/ml to form cell-gel fluid. The cell-gel fluid was dropped into the porous calcium polyphosphate fiber/poly-L-lactic acid(CPPf/PLLA)scaffold, and a cell-gel-scaffold complex formed after being solidified. The defect models of 40% upper tibial epiphyseal plate were made in 72 immature rabbits; they were divided into 4 groups: group A(the cell-gel-scaffold complex was transplanted into the defect and the gap filled with chondrocyte-gel fluid), group B (with noncell CPPf/PLLA scaffold), group C(with fat) and group D(with nothing). The changes of roentgenograph, gross and histology were investigated after 2, 4, 6, 8, 12 and 16 weeks of operation. RESULTS: In group A, the typical histological structure of epiphyseal plate derived from the engineered cartilage with a fine integration between host and donor tissues after 2 weeks. The repaired epiphyseal plate had normal histological structure without deformation of tibia after 4 weeks. The early histological change of epiphyseal closure appeared in the repaired area with varus and shortening deformation of the tibia after 8 weeks. The epiphyseal plate was closed in the repaired area with more evident deformation of tibia; the growth function of repaired epiphyseal plate was 43.6% of the normal one. In groups B, C and D, deformation of tibia occurred after 2 weeks; the defect area of epiphyseal plate was completely closed after 4 weeks. The deformation was very severe without growth of the injured epiphyseal plate after 16 weeks, and no significant difference was observed between the three groups. CONCLUSION: Engineered epiphyseal cartilage can repair the epiphyseal defect in the histological structure with partial recovery of the epiphyseal growth capability. Injecting the suspension of fluid chondrocyte-gel into the defects induces a fine integration of host and donor tissues.
Objective To investigate the therapeutic effectof the modified anterior approach in treatment of the patients with cervicothoracic junction spinal lesions. Methods From September 2000 to January 2005, 23 patients (15 males, 8 females) with spinal lesions in the cervicothoracic junction underwent a standard cervical approach, which was combined with apartial median steotomy and transverse steotomy through the synostosis between the manubrium and body of the sternum to expose the lesion adequately. Among thepatients, 3 had fracture, 7 had dislocation, 6 had tuberculosis, and 7 had tumor. The pathologic change regions was as follows: 2 in the C6-T1 segment, 2in the C6-T2 segment, 3 in the C7-T1 segment, 3 in the T3 segment, 8 in the T1 segment, and 5 in the T2egment. The classification of Frankel were as follows: 2 at grade A, 4 at grade B, 7 at grade C, 4 at grade D, and 6 at grade E. All the patients underwent a radical excision of the affected spinal bone, were given a proper tricortical iliac crest and anterior instrumentation to reconstruct the anterior spinal column, followed by immobilization in a brace for 3-6 months. Results The mean followup period was 30 months (range, 1042 months). Bony fusion was obtained in all the patients.One patient died of pulmonary cancer metastasis 10 months after operation. The nerve function of the spinal cord recovered at different degrees (1 at grade A, None at grade B, 2 at grade C, 10 at grade D, 10 at grade E). Conclusion Ourmodified anterior approach can provide a direct and safe access to the lesions in the region.
Objective To observe the efficiency and biological characteristics in regenerating in vitro tissue-engineered cartilage from epiphyseal chondrocyte-scaffold complex. MethodsThe first passage epiphyseal chondrocytes were collected and mixed with the biological gel-matrix, the chondrocyte-gel fluid wasdropped into the scaffold to form a complex. The complexes were in vitro cultivated. The changes of complexes in morphology and synthesis of collagens type ⅡandtypeⅠ and aggrecan were observed under the gross and the inverted and light microscopes. The sulfate GAG content in complexes was measured by the the modified dimethylmethylene blue method. Results During cultivation, thecomplexes could keep its original shape with the stable homogeneous three-dimensional distribution of chondrocytes，gradually became milk white and translucence with their rigidity increasing. In the 1st week, the chondrocytic lacunae formed in the complexes. After 2 weeks, the complex was gradually reorganized into the mature engineered cartilage with rich collagen typeⅡand aggrecan and typical cartilage histological structure, but with negative immunological staining of collagen typeⅠ. In the 4th week, the engineered cartilage resembled the nature epiphyseal plate in the characteristic of histological structure, and had over 34% of the sulfate GAG content of the natural epiphyseal plate. Conclusion Theepiphyseal chondrocyte-scaffold complex can be reorganized into typical cartilage with the epiphyseallike histological structure, and be fit for repairing the epiphyseal defect. The tissue engineered cartilage cultivated for 1-2 weeks may be a good choice for repairing epiphyseal defect.
Aiming at the problem that the unbalanced distribution of data in sleep electroencephalogram(EEG) signals and poor comfort in the process of polysomnography information collection will reduce the model's classification ability, this paper proposed a sleep state recognition method using single-channel EEG signals (WKCNN-LSTM) based on one-dimensional width kernel convolutional neural networks(WKCNN) and long-short-term memory networks (LSTM). Firstly, the wavelet denoising and synthetic minority over-sampling technique-Tomek link (SMOTE-Tomek) algorithm were used to preprocess the original sleep EEG signals. Secondly, one-dimensional sleep EEG signals were used as the input of the model, and WKCNN was used to extract frequency-domain features and suppress high-frequency noise. Then, the LSTM layer was used to learn the time-domain features. Finally, normalized exponential function was used on the full connection layer to realize sleep state. The experimental results showed that the classification accuracy of the one-dimensional WKCNN-LSTM model was 91.80% in this paper, which was better than that of similar studies in recent years, and the model had good generalization ability. This study improved classification accuracy of single-channel sleep EEG signals that can be easily utilized in portable sleep monitoring devices.
ObjectiveTo explore the influence of 5 mm surgical margin (SM) width on the prognosis of patients with solitary hepatocellular carcinoma (HCC) and the influence of tumor size and microvascular invasion (MVI) on strategic decision of SM width.MethodsThe clinicopathologic data of patients with solitary HCC underwent the surgical resection in the West China Hospital of Sichuan University from January 2014 to September 2015 were collected. According to the inclusion and exclusion criteria of this study, the prognostic differences of the patients with SM≤5 mm and SM>5 mm were compared after the propensity score matching (PSM), and the influences of the 5 mm SM on the recurrence-free survival rate of large HCC (>5 cm) or small HCC (≤5 cm) and MVI positive or negative patients were analyzed.ResultsA total of 266 eligible patients were included, with a median overall survival of 40.01 months and a median recurrence-free survival of 37.01 months. During the follow-up period, 137 patients recurred and 75 patients died. After PSM, the basic indexes had no significant differences between the patients with SM>5 mm (n=78) and SM≤5 mm (n=78). The results of the multivariate Cox regression analysis showed that the tumor size and MVI were the important factors of the recurrence-free survival (P<0.05) and the tumor size, MVI, HBeAg, and alpha-fetoprotein (AFP) were the important factors of the overall survival (P<0.05) before the PSM; while the MVI and SM were the important factors of the recurrence-free survival (P<0.05), the gender, AFP, and MVI were the important factors of the overall survival (P<0.05) after the PSM. The recurrence-free survival rate of the patients with SM >5 mm had better than that with SM≤5 mm after the PSM, but the overall survival had no difference. In the MVI negative and large HCC subgroups, the patients with SM>5 mm showed the better recurrence-free survival rate. However, in the MVI positive and small HCC subgroups did not show any differences in the recurrence-free survival rate for the different SM widths.ConclusionsAccording to the results of this study, a wider SM (>5 mm) could improve recurrence-free survival in patients with a single tumor within BCLC stage 0/A. For patients without MVI or large HCC, SM>5 mm might be adequate. However, for patients with MVI or small HCC, the determination of an appropriate SM width needs further to be investigated.