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1.
Objective To study the influence of molecular weight of chitosan on microcapsules and hepatocytes in microcapsules. Methods The mechanical strength, permeability to fluoresceine isothiocyanate-bovine serum albumin (FITC-BSA) and activity of hepatocytes in microcapsules were compared between two kinds of microcapsules made by low and middle molecular weight chitosan. Results After 100 min of stirring microcapsules, all middle molecular weight chitosan microcapsules were damaged, 5% low molecular weight chitosan microcapsules were damaged. There was significant difference in breakage rate of the mechanical strength between two microcapsules (P < 0. 05). Fifteen min after addition of FITCBSA into microcapsule solution, fluorescence intensity in the low molecular weight chitosan microcapsules was 4 AU, and that in middle molecular weight of chitosan microcapsules was 1. 5 AU, suggesting there was significant difference in permeability to FITC-BSA between two kinds of microcapsules (P < 0. 05).One week after culture of microencapsulated hepatocytes, staining test showed that 100% of liver cells in low molecular weight chitosan microcapsules were alive, while the number was about 40% in middle molecular weight chitosan microcapsules (P < 0. 05). Conclusion Low molecular weight chitosan is more suitable as materials of microcapsules than molecular weight chitosan.  相似文献   

2.
目的 观察壳聚糖相对分子质量对微囊机械强度和通透性及包裹肝细胞活性的影响.方法 通过微囊搅拌实验比较中、低分子量壳聚糖形成的微囊的机械强度,比较2种微囊对异硫氰酸荧光素标记的牛血清白蛋白(FITC-BSA)通透性,及细胞染色实验判断2种微囊包裹小鼠原代肝细胞活性的区别.结果 微囊搅拌100 min后中分子量壳聚糖微囊破损率100%,低分子量壳聚糖微囊破损率5%,两种微囊机械强度差异有统计学意义(P<0.05),微囊溶液中加入HTC-BSA15 min后,低分子量壳聚糖微囊内荧光强度为4 AU,中分子量壳聚糖微囊内荧光强度为1.5 AU,两种微囊对FITC-BSA的通透性差异有统计学意义(P<0.05),低分子量壳聚糖形成的微囊包裹肝细胞培养1周后细胞染色实验显示微囊中活肝细胞数为100%,中分子量壳聚糖形成的微囊包裹的活肝细胞数约为40%,两者差异有统计学意义(P<0.05).结论 低分子量壳聚糖相对于中分子量壳聚糖更适合于作微囊的材料.
Abstract:
Objective To study the influence of molecular weight of chitosan on microcapsules and hepatocytes in microcapsules. Methods The mechanical strength, permeability to fluoresceine isothiocyanate-bovine serum albumin (FITC-BSA) and activity of hepatocytes in microcapsules were compared between two kinds of microcapsules made by low and middle molecular weight chitosan. Results After 100 min of stirring microcapsules, all middle molecular weight chitosan microcapsules were damaged, 5% low molecular weight chitosan microcapsules were damaged. There was significant difference in breakage rate of the mechanical strength between two microcapsules (P < 0. 05). Fifteen min after addition of FITCBSA into microcapsule solution, fluorescence intensity in the low molecular weight chitosan microcapsules was 4 AU, and that in middle molecular weight of chitosan microcapsules was 1. 5 AU, suggesting there was significant difference in permeability to FITC-BSA between two kinds of microcapsules (P < 0. 05).One week after culture of microencapsulated hepatocytes, staining test showed that 100% of liver cells in low molecular weight chitosan microcapsules were alive, while the number was about 40% in middle molecular weight chitosan microcapsules (P < 0. 05). Conclusion Low molecular weight chitosan is more suitable as materials of microcapsules than molecular weight chitosan.  相似文献   

3.
Objective Branched polyethylene glycols (PEG) with different molecular weight were cross-linked to the porcine decellularized aortic valve (DAV) and the effects of PEG cross-linking on the mechanical properties were investigated. Methods A total of 25 porcine DAVs were randomly assigned into 5 groups: PEG3400, PEG8000, PEG12000, PEG20000 and control. The reactive time was 4 h at room temperature. The efficiency of crosslinking was calculated by measuring the residual thiol group. The mechanical properties were obtained by static tensile test. Results The efficiency of crosslinking was 92. 40% , 89. 88% , 87. 87% and 87. 46% in PEG3400, PEG8000, PEG12000, PEG20000 groups, respectively. As compared with other groups, the PEG3400 group had significantly greater increase in the crosslinking degree (P < 0. 05). Tensile test showed the tensile strength of PEG12000 and PEG20000 groups was (3. 22 ±0.41) and (3. 19 ±0. 15) MPa, respectively, and significantly different from that in control group (P < 0. 05). The tensile strength and young' s modulus had a positive correlation with the molecular weight of PEG. Conclusion Branched PEG with the molecular weight of 12 000 Da and 20 000 Dacan effectively crosslink to the porcine decellularized aortic valves and improve their mechanical behaviors, and has the potential to be used as the material of fabricating new hybrid scaffold of tissue engineering heart valves.  相似文献   

4.
Objective Branched polyethylene glycols (PEG) with different molecular weight were cross-linked to the porcine decellularized aortic valve (DAV) and the effects of PEG cross-linking on the mechanical properties were investigated. Methods A total of 25 porcine DAVs were randomly assigned into 5 groups: PEG3400, PEG8000, PEG12000, PEG20000 and control. The reactive time was 4 h at room temperature. The efficiency of crosslinking was calculated by measuring the residual thiol group. The mechanical properties were obtained by static tensile test. Results The efficiency of crosslinking was 92. 40% , 89. 88% , 87. 87% and 87. 46% in PEG3400, PEG8000, PEG12000, PEG20000 groups, respectively. As compared with other groups, the PEG3400 group had significantly greater increase in the crosslinking degree (P < 0. 05). Tensile test showed the tensile strength of PEG12000 and PEG20000 groups was (3. 22 ±0.41) and (3. 19 ±0. 15) MPa, respectively, and significantly different from that in control group (P < 0. 05). The tensile strength and young' s modulus had a positive correlation with the molecular weight of PEG. Conclusion Branched PEG with the molecular weight of 12 000 Da and 20 000 Dacan effectively crosslink to the porcine decellularized aortic valves and improve their mechanical behaviors, and has the potential to be used as the material of fabricating new hybrid scaffold of tissue engineering heart valves.  相似文献   

5.
Objective To investigate the effect of the soybean isoflavones at different estrogen environments on the pathogenesis of breast cancer in MMTV-erbB-2 transgenic mice. Methods 150 fiveweek-old MMTV-erbB-2 transgenic female mice were phosen and divided into five groups; control group,low estrogen group 1, low estrogen group 2, high estrogen group 1 and high estrogen group 2. The incidence and latent period of breast cancer were observed, and the expression of estrogen receptor (ER) ,progesterone receptor (PR), and proliferating cell nuclear antigen (PCNA) proteins was detected by using immunohistochemistry SP method. Results The incidence of breast cancer in control group, low estrogen group 1, low estrogen group 2, high estrogen group 1 and high estrogen group 2 was 73. 3% , 96. 7% ,30. 3% , 40. 0% and 83. 3% , respectively, with the difference being not significant between control group and high estrogen group 2, and between low estrogen group 1 and high estrogen group 2 (P > 0. 05 ) , but with the difference being significant among the other groups (P < 0. 05 ). There was significant difference in the average latent period of breast cancer among all groups (P > 0. 05 ). There was significant difference in the number of TEB between low-estrogen group 1 and other groups (P < 0.05). There was significant difference in the erbB-2 expression among the groups ( P > 0. 05 ). There was no significant difference in the expression of breast ER and PR between control group and other groups ( P > 0. 05 ). The PCNA expression in breast tumor tissue in low-estrogen group 1 was significantly higher than other groups (P <0. 05) , and there was significant difference in the PCNA expression between control group and high estrogen group 2, between low estrogen group 1 and high estrogen group 2 (P < 0. 05). Conclusion The soybean isoflavones at different estrogen environments play different roles in the occurrence and development of MMTV-erbb-2 transgenic mouse mammary tumor. In the context of low estrogen, soybean isoflavones could even promote breast cancer formation and development. In the context of high estrogen, soybean isoflavones could inhibit breast cancer and development.  相似文献   

6.
Objective To investigate the effect of the soybean isoflavones at different estrogen environments on the pathogenesis of breast cancer in MMTV-erbB-2 transgenic mice. Methods 150 fiveweek-old MMTV-erbB-2 transgenic female mice were phosen and divided into five groups; control group,low estrogen group 1, low estrogen group 2, high estrogen group 1 and high estrogen group 2. The incidence and latent period of breast cancer were observed, and the expression of estrogen receptor (ER) ,progesterone receptor (PR), and proliferating cell nuclear antigen (PCNA) proteins was detected by using immunohistochemistry SP method. Results The incidence of breast cancer in control group, low estrogen group 1, low estrogen group 2, high estrogen group 1 and high estrogen group 2 was 73. 3% , 96. 7% ,30. 3% , 40. 0% and 83. 3% , respectively, with the difference being not significant between control group and high estrogen group 2, and between low estrogen group 1 and high estrogen group 2 (P > 0. 05 ) , but with the difference being significant among the other groups (P < 0. 05 ). There was significant difference in the average latent period of breast cancer among all groups (P > 0. 05 ). There was significant difference in the number of TEB between low-estrogen group 1 and other groups (P < 0.05). There was significant difference in the erbB-2 expression among the groups ( P > 0. 05 ). There was no significant difference in the expression of breast ER and PR between control group and other groups ( P > 0. 05 ). The PCNA expression in breast tumor tissue in low-estrogen group 1 was significantly higher than other groups (P <0. 05) , and there was significant difference in the PCNA expression between control group and high estrogen group 2, between low estrogen group 1 and high estrogen group 2 (P < 0. 05). Conclusion The soybean isoflavones at different estrogen environments play different roles in the occurrence and development of MMTV-erbb-2 transgenic mouse mammary tumor. In the context of low estrogen, soybean isoflavones could even promote breast cancer formation and development. In the context of high estrogen, soybean isoflavones could inhibit breast cancer and development.  相似文献   

7.
Objective To analyze the effect of acromio-humeral interval on the occurrence of subacromial impingement syndrome (SIS) after the clinical application of clavicular hook plate in acromioclavicular joint dislocation (Tossy Ⅲ). Methods From July 2005 to October 2008, 63 cases of acromioclavicular joint dislocation (Tossy Ⅲ) were treated with clavicular hook plate. There were 48 males and 15 females with an average age of 33.6 years (range, 21-53 years). The relationship of the acromio-humeral interval (AHI)were analysed between the two groups by X-ray measurement. The AHI and plate-humeral interval (PHI)were measured on X-ray film to detect difference between the two groups. Results After the operation, all t he 63 cases were divided into two groups according the occurrence of SIS. There were 14 cases in the group of SIS and 49 cases in the group without SIS. The mean follow-up was 12.2 (average, 6-15) months.The average AHI of was (8.5±2.1) mm and (9.7±2.6) mm in the group of SIS and the group without SIS respectively. The difference between the two groups was statistically significant. The average PHI of the group of SIS and the group without SIS was (6.1±2.8) mm and (6.8±2.4) mm respectively. There was no difference between the two groups. After removal of the clavicular hook plate, the clinical sign disappeared in the group of SIS. According the Karlsson scoring system, the excellent and good rate of the shoulder function was 100%. Conclusion The occurrence of SIS after the clinical application of clavicular hook plate has related to the width of the subacromial interval. The syndrome could be treated by the removal of clavicular hook plate.  相似文献   

8.
Objective To analyze the effect of acromio-humeral interval on the occurrence of subacromial impingement syndrome (SIS) after the clinical application of clavicular hook plate in acromioclavicular joint dislocation (Tossy Ⅲ). Methods From July 2005 to October 2008, 63 cases of acromioclavicular joint dislocation (Tossy Ⅲ) were treated with clavicular hook plate. There were 48 males and 15 females with an average age of 33.6 years (range, 21-53 years). The relationship of the acromio-humeral interval (AHI)were analysed between the two groups by X-ray measurement. The AHI and plate-humeral interval (PHI)were measured on X-ray film to detect difference between the two groups. Results After the operation, all t he 63 cases were divided into two groups according the occurrence of SIS. There were 14 cases in the group of SIS and 49 cases in the group without SIS. The mean follow-up was 12.2 (average, 6-15) months.The average AHI of was (8.5±2.1) mm and (9.7±2.6) mm in the group of SIS and the group without SIS respectively. The difference between the two groups was statistically significant. The average PHI of the group of SIS and the group without SIS was (6.1±2.8) mm and (6.8±2.4) mm respectively. There was no difference between the two groups. After removal of the clavicular hook plate, the clinical sign disappeared in the group of SIS. According the Karlsson scoring system, the excellent and good rate of the shoulder function was 100%. Conclusion The occurrence of SIS after the clinical application of clavicular hook plate has related to the width of the subacromial interval. The syndrome could be treated by the removal of clavicular hook plate.  相似文献   

9.
腹腔镜结直肠癌根治术疗效分析   总被引:6,自引:1,他引:5  
Objective To investigate the efficacy of laparoscopic radical resection for colorectal cancer. Methods From September 2000 to December 2004, 99 patients with colorectal cancer underwent laparoscopic radical resection (laparoscopic group) and 198 patients with colorectal cancer underwent open radical resection (open group) at the Union Hospital of Fujian Medical University. The differences in local recurrence and survival between the two groups were compared. The local recurrence of tumors and survival of patients in the two groups were calculated by the life-table method, and were compared by the Wilcoxon (Gehan) test, chi-square test and Fisher's exact test. The recurrence interval and survival time of the two groups were compared by non-parametric Wilcoxon rank sum test. Results The 2-and 3-year local recurrence rates in the laparoscopic group were both 3.0% and the overall local recurrence rate was 3.0% (3/99). The 2-and 3-year local recurrence rates in the open group were 2.6% and 4.0% , respectively, and the overall local recurrence rate was 3.5% (7/198), with no significant difference between the two groups (χ2 =0.002, P > 0. 05). The median survival time of patients with local recurrence was 15 months (range, 7-24 months) in the laparoscopic group and 11 months (range, 2-28 months) in the open group, with no significant difference between the groups (U = 15. 500, P >0. 05). The 1-year survival rate was 33.3% in the laparoscopic group and 42.9% in the open group. The 2-year survival rate was zero in the laparoscopic group and 42. 9% in the open group. There were no significant differences between the groups for the 1-and 2-year survival rates (χ2 =0.120, P>0.05). Conclusions The efficacy of laparoscopic radical resection for colorectal cancer is similar to that of open surgery. Laparoscopic radical resection for colorectal cancer is safe and feasible, and does not increase the recurrence rate of cancer.  相似文献   

10.
Objective To investigate the efficacy of laparoscopic radical resection for colorectal cancer. Methods From September 2000 to December 2004, 99 patients with colorectal cancer underwent laparoscopic radical resection (laparoscopic group) and 198 patients with colorectal cancer underwent open radical resection (open group) at the Union Hospital of Fujian Medical University. The differences in local recurrence and survival between the two groups were compared. The local recurrence of tumors and survival of patients in the two groups were calculated by the life-table method, and were compared by the Wilcoxon (Gehan) test, chi-square test and Fisher's exact test. The recurrence interval and survival time of the two groups were compared by non-parametric Wilcoxon rank sum test. Results The 2-and 3-year local recurrence rates in the laparoscopic group were both 3.0% and the overall local recurrence rate was 3.0% (3/99). The 2-and 3-year local recurrence rates in the open group were 2.6% and 4.0% , respectively, and the overall local recurrence rate was 3.5% (7/198), with no significant difference between the two groups (χ2 =0.002, P > 0. 05). The median survival time of patients with local recurrence was 15 months (range, 7-24 months) in the laparoscopic group and 11 months (range, 2-28 months) in the open group, with no significant difference between the groups (U = 15. 500, P >0. 05). The 1-year survival rate was 33.3% in the laparoscopic group and 42.9% in the open group. The 2-year survival rate was zero in the laparoscopic group and 42. 9% in the open group. There were no significant differences between the groups for the 1-and 2-year survival rates (χ2 =0.120, P>0.05). Conclusions The efficacy of laparoscopic radical resection for colorectal cancer is similar to that of open surgery. Laparoscopic radical resection for colorectal cancer is safe and feasible, and does not increase the recurrence rate of cancer.  相似文献   

11.
海藻酸-壳聚糖-聚乙烯乙二醇微囊生物相容性的研究   总被引:11,自引:0,他引:11  
目的比较海藻酸-壳聚糖-聚乙烯乙二醇微囊(ACP微囊)和海藻酸-聚赖氨酸-海藻酸微囊(APA微囊)的生物相容性。方法(1)两种微囊(50、100和200个)与健康人血清共浴,检测微囊对补体的激活程度。(2)1000个APA和ACP微囊分别植入Wistar大鼠的腹腔,4d和3周时统计取出的微囊数和微囊的纤维化率。(3)Wistar大鼠胰岛用ACP微囊和APA微囊包裹,分别贯续置于含3.3mmol/L和16.7mmol/L葡萄糖的Hank's溶液中培养,测定培养液中胰岛素的浓度。结果(1)ACP微囊组残余补体活性高于APA微囊组。(2)4d时,ACP和APA微囊的取出数分别是845.0±40.4和807.6±45.7(P>0.05),囊周纤维化率分别是16.40%和65.68%(P<0.05);3周时两种微囊的取出数分别为715.0±133.0和367.5±105.6(P<0.05),囊周纤维化率为27.8%和83.9%(P<0.05)。(3)在含3.3mmol/L葡萄糖的Hank's液中,未微囊胰岛组、APA和ACP微囊化胰岛组的胰岛素浓度分别是(123.48±4.70)mIU/L、(110.11±12.18)mIU/L和(110.90±11.95)mIU/L,当葡萄糖浓度为16.7mmol/L时,胰岛素浓度分别是(754.75±13.81)mIU/L、(689.30±27.71)mIU/L和(684.28±70.10)mIU/L。结论海藻酸-壳聚糖-聚乙烯乙二醇微囊的生物相容性要优于海藻酸-聚赖氨酸-海藻酸微囊,前者更适合应用于微囊化胰岛移植。  相似文献   

12.
Xenotransplantation of cells using biodegradable microcapsules   总被引:9,自引:0,他引:9  
BACKGROUND: The use of immunoisolation to protect transplanted cells from the immune system of the host has broad application to the treatment of major diseases such as diabetes and a wide range of other disorders resulting from functional defects of native cell systems. In most cases, limitations in functional cell longevity will necessitate periodic replenishment of the cells. We describe a hydrogel-based microcapsule that breaks down at a rate that can be adjusted to correspond to the functional longevity of the encapsulated cells. These injectable capsules can be engineered to degrade over several weeks to months for short-term drug delivery, or to remain intact and immunoprotective for more extended periods. When the supply of cells needs to be replenished, no surgery will be required to localize and remove the old capsules. METHODS: Porcine and bovine islets were immobilized in "composite" microcapsules fabricated from alginate and low-relative molecular mass (Mr) poly (L-lysine[PLL]) (Mr exclusion <120 Kd) and implanted into the peritoneum of normal and streptozotocin-induced diabetic rats. In addition to demonstrating long-term islet viability and function, a series of in vitro studies were carried out to determine the permeability and biodegradability of the microcapsules used in the present system. RESULTS: Xenogeneic islets implanted in nonimmunosuppressed rats remained in excellent condition indefinitely (>40 weeks)(viability was comparable to that of preimplant control specimens). In contrast, no islets survived in uncoated alginate spheres after 2 weeks postimplantation. By changing the concentration of the alginate, it was possible to vary the rate of capsule breakdown in rats from mechanically unstable (outer matrix <0.5-0.75% alginate) to stable for >1 year (> or =1.5% alginate). In addition to in vivo breakdown studies, the biodegradability of the capsular components was verified in vitro using a mixture of tritosomes (enzymes isolated from animal cells). CONCLUSIONS: We have designed a microcapsule system with controllable biodegradability which allows breakdown and absorption of implants when the cells die or become functionally inactive. These results may have application to other alginate-PLL encapsulation systems. The ability to cross species lines using these biodegradable microcapsules has the potential to expand dramatically the number of patients and the scope of diseases that can be successfully treated with cellular therapy.  相似文献   

13.
A bioartificial pancreas, a medical device entrapping islets of Langerhans (islets) in an immunoisolative membrane, has been regarded as one of the most promising approaches to treat insulin-dependent diabetic patients. In this study, various modifications of alginate-chitosan microcapsules were made such as the inclusion of polyethylene glycol (PEG) and the use of crosslinkers such as carbodiimide (EDC) and glutaraldehyde (GA) in the core and onto the microcapsule membrane surface. A characterization of the modified microcapsules in terms of mechanical stability and albumin diffusion as well as their surface properties using SEM was performed. A mild GA treatment greatly enhanced the mechanical stability of the microcapsules, and this treatment did not affect the coating process of chitosan or PEG. The biological response to such microcapsules was evaluated by microencapsulation of red blood cells (RBC) and subsequent observation of their hemoglobin release. The encapsulated RBC in the PEG-GA coated microcapsules were found to be less hemolytic and had improved stability and biocompatibility. The results suggest the possibility of developing biological assist organs by microencapsulation of mammalian cells such as islets or liver cells in immunoisolative microcapsules in the near future.  相似文献   

14.
Cisplatin containing microcapsules (CDDP-MC) were prepared by encapsulating cisplatin suspended in a dispersing agent in a copolymer (lactic acid) matrix using an in water drying method. Cisplatin release from the microcapsules was controlled by the addition of albumin. The CDDP-MC were relatively stable in storage, and there was only minimal initial release of the cisplatin from the microcapsules. The antitumor effects of this sustained release dosage form of cisplatin were evaluated in vitro and in vivo in mice. Mice were given an intraperitoneal (i.p.) injection of CDDP-MC 24 h after inoculation with tumor cells. The CDDP-MC were effective against Ehrlich ascites tumors and showed reduced acute toxicity compared with standard cisplatin solution. Due to the small initial release of the cisplatin from the microcapsules, however, the antitumor effect of the CDDP-MC was weaker than that of cisplatin solution. Conventional sustained release preparations have been reported to have large particle sizes and demonstrate large releases of cisplatin from microcapsules. They have been considered more effective than cisplatin solution because of the large initial release of cisplatin from the microcapsules and the maintenance of drug levels. The antitumor effect of our slow-release formulation of cisplatin was evaluated by administration of CDDP-MC 1, 4, and 7 days before i.p. implantation of tumor cells. The survival time of the tumor-bearing mice was prolonged in the CDDP-MC group, but not in the group treated with cisplatin solution. By using this modified formulation of cisplatin, the toxicity of the drug can be reduced, and effective concentrations of the drug can be maintained locally for prolonged periods of time.  相似文献   

15.
Ito Y  Chang TM 《Artificial organs》1992,16(4):422-427
To make highly differentiated encapsulated hepatocytes, we formed hepatocyte spheroids in microcapsules in cultures. Hepatocytes isolated from rats were encapsulated in alginate-poly-L-lysine artificial cells and cultured under different medium conditions. When high molecular weight poly-L-lysine was used to make the capsule membrane, the hepatocytes aggregated and formed spheroids inside microcapsules within 48 hs. We studied the viability and function of encapsulated hepatocyte spheroids; free hepatocyte spheroids; nonaggregated encapsulated hepatocytes; and free hepatocyte monolayers. Cell viability and protein-producing ability were monitored for up to 30 days. Hepatocyte spheroids in the encapsulated or free form remained viable and continued to secrete proteins throughout the 30 days of observation. The viability and function of nonaggregated hepatocytes in the encapsulated or free form declined rapidly. These results suggest that the tridimensional structure of the spheroids may be important in maintaining the viability and function of encapsulated hepatocytes.  相似文献   

16.
肝细胞海藻酸钡微囊生物性能的研究   总被引:1,自引:1,他引:0  
目的 研究肝细胞海藻酸钡微囊的生物学性能。方法 大鼠肝细胞微囊化后移植于腹腔内 ,1个月后取出行组织学检查。结果 不含肝细胞的空囊移植组微囊大多保持良好的形状 ,囊壁光滑、完整 ,囊外无纤维化反应 ,回收率为 ( 89± 2 3) %。肝细胞微囊大部分呈游离状态 ,部分囊外有一薄层纤维层附着 ,回收率为 ( 78± 2 1) % ;囊内细胞存活率由移植前的 ( 91± 16 ) %降至 ( 79±13) %。结论 肝细胞海藻酸钡微囊的生物相容性及机械稳定性较好 ,但免疫源性有待进一步提高。  相似文献   

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