AIM: To study the immuno-modulatory effect of resveratrol (RES) on allograft rejection after liver transplantation in rats. METHODS: Male Sprague-Dawley (SD) rats were selected as donors and male Wistar rats as ...AIM: To study the immuno-modulatory effect of resveratrol (RES) on allograft rejection after liver transplantation in rats. METHODS: Male Sprague-Dawley (SD) rats were selected as donors and male Wistar rats as recipients for a rejection model. The recipients were divided into four groups after orthotopic liver transplantation (OLTx). In the RES A, B, and C groups, RES was given intra-peritoneally once a day (25, 50, and 100 mg/kg, respectively) after OLTx, whereas in the control group, vehicle buffer was given intra-peritoneally once a day. The survival time, serum chemistry, production of cytokines, activation of transcription factor NF-kB, and histopathologic findings were then compared among these groups. RESULTS: The mean survival time after OLTx in the RES C group was significantly longer than that in the control group (16.7+-1.2 d ,vs9.3+-0.6 d, P〈0.01). On the 7th posttransplant day the serum albumin level significantly improved in the RES C group, the serum total bile acid and alanine aminotransferase (ALT) levels were significantly lower in the RES C group, the serum IL-2 and INF-y levels were significantly lower in the RES C group, and the activation of transcription factor NF-kB in peripheral blood T lymphocytes was significantly suppressed in the RES A, B, and C groups in comparison to those in the control group. On the 7^th post-transplant day, a histological examination revealed apparent difference in the severity of rejection between the RES C group and control group. CONCLUSION: RES has an immuno-suppressive property as well as protective effect on hepatocytes under allograft rejection. It might serve as a novel agent for reducing the severity of hepatic allograft rejection in rats.展开更多
Objective: To evaluate the functional outcome and complications of allograft replacement in management of bone tumors. Methods: Between March 1992 and September 2002, 164 patients underwent bone tumor resection and ...Objective: To evaluate the functional outcome and complications of allograft replacement in management of bone tumors. Methods: Between March 1992 and September 2002, 164 patients underwent bone tumor resection and massive allograft reconstruction of bone defects. The length of the resected part ranged from 5-35 cm. The resections were classified as marginal or wide resections of the tumor on the basis of the Musculoskeletal Tumor Society staging system. Fresh-frozen allografts were employed as osteoarticular grafts (n = 95), hemi-condylar (n = 15), massive (n = 23), allograft-prosthesis composite (n = 12), intercalary grafts (n = 15) or hemi-pelvic grafts (n = 4). Most of the lesions were osteosarcoma and giant cell tumor of bone and located in proximal and distal femur, proximal tibia and humerus. Results: At a median follow-up of 47 months (range, 12 to 168 months) after the operation, 154 of the patients in the study were free of disease and 10 died of disease. Twenty-one (12.8%) patients had local recurrence and 38 (23.2%) nonunion. Late complications included 11 (6.7%) fractures of the allograft and 18 (11.0%) infections of the graft, instability of the joint in the form of subluxation was noted in 13 (7.9%) patients. Ten extremities were amputated due to local recurrence or severe infection. Conclusion: AIIografts can be used for reconstruction of bony defects after tumor resection. AIIograft has nearly similar shape, strength, osteo-inductivity and osteo-conductivity with host bone. AIIograft implantation is a high complication reconstruction method, and the dsk of recurrence increases when less surgical margin achieves.展开更多
Objective.The purpose of this study was to assess the renal graft expression of ICAM 1(intercellular adhesion molecule 1) and LFA 1(lymphocyte function associated antigen 1)molecule with rela...Objective.The purpose of this study was to assess the renal graft expression of ICAM 1(intercellular adhesion molecule 1) and LFA 1(lymphocyte function associated antigen 1)molecule with relation to graft rejection. Methods.Rat kidney transplantation was performed according to the procedure of Kamada with some modification.Experimental rats were divided into 5 groups.The survival time of recipient rats and function of grafts after renal transplantation were observed.The sections of renal graft were stained for monoclonal antibody ICAM 1 and LFA 1, and then quantification of ICAM 1 and LFA 1 expression was accomplished by computer image analysis. Results.ICAM 1 and LFA 1 increased significantly in the renal allograft rejection group as compared with the non rejection groups(P<0 05). Conclusion.Both biopsy of renal graft and monitoring of ICAM 1 and LFA 1 are useful tools in diagnosing and treating acute rejection.展开更多
The activation of T cells to differentiate and to proliferate is an essential step in the immune response to antigen, especially in cell mediated acute allograft rejection. Besides the int...The activation of T cells to differentiate and to proliferate is an essential step in the immune response to antigen, especially in cell mediated acute allograft rejection. Besides the interaction of CD3/TCR complex with Ag/MHC complex presented on antigen presenting cells, a complete T cell activation and proliferation requires a second costimulatory signal. The interaction of CD28/CTLA 4 and B7 is a major costimulatory pathway for T Cell activation. Inhibition of this pathway results in development of antigen specific unresponsiveness and clonal anergy.In present study,the biologic function of anti CD28 monoclonal antibody and its Fab fragment were investigated in vitro and in vivo.The results indicate that mAbCD28 and its Fab fragments could promote the functional recovery of allografts and prolong the graft survival,but could not reverse the acute rejection or induce transplantation tolerance in the rat PTG allograft model. We also found that peripheral TNF α level and NK cell activity were suppressed in the presence of mAbCD28 and its Fab fragments for a relatively long time after PTG transplantation.展开更多
Objective:To explore the peculiarities of kidney transplantation in elderly patients and define the perioperative managements. Methods: The clinical data of kidney transplantation in 29 patients older than 65years wer...Objective:To explore the peculiarities of kidney transplantation in elderly patients and define the perioperative managements. Methods: The clinical data of kidney transplantation in 29 patients older than 65years were reviewed, the eldest being 84 years old and the mean age 68. 1 years. Results: Four episodes of acute rejection (13. 80%) were encountered. FK506 toxicity occurred in one case (3.40%) and lung infection in another (3.40%), who (along with the former 4 patients) all were cured subsequently. In one case, the kidney graft was removed for thrombogenesis of the renal artery. The 1- and 3-year patients/grafts survival of 100% and 96.5% respectively was achieved, with the longest survival exceeding 5 years. Conclusions:Old age was not the absolute contraindication for kidney transplantation. Strict observance of the indications of kidney transplantation and donor selection with well-matched tissue-typing are crucial in elderly patients.Adequate application of immunosuppressants and effective long-term follow-up are also major factors for long-term allograft survival.展开更多
To investigate the influence of mycophenolate mofetil (MMF) upon the maturation and the allo-stimulatory activity of cultured progenitors of dendritic cells (DCp), and to evaluate the effects of the pre-treated dentri...To investigate the influence of mycophenolate mofetil (MMF) upon the maturation and the allo-stimulatory activity of cultured progenitors of dendritic cells (DCp), and to evaluate the effects of the pre-treated dentritic cells of recipients with MMF on the tolerance induction as well as its possible mechanism, GM-CSF and MMF were added to the in vitro cultured progenitor cells, and the immuno-phenotypical analysis was performed by means of flow cytometry. The secretion of IL-12 was detected by ELISA and the stimulatory activities of DCp on allogeneic T cells were observed by mixed lymphocyte reaction. Twenty-four C57BL/6 mice were divided into 3 groups (each with 8 mice), in which group A of mice accepted allografts of heart from BALB/c mice, group B of mice had received untreated DCp from donors of BALB/c mice 7 days before transplantation, and C57BL/6 mice in group C were treated by injection with MMF-treated allografts of heart from BALB/c mice 7 days before transplantation. The survival times of allografts and the changes of the cytokine levels in sera of the recipient mice were observed after transplantation. The experimental results showed that MMF could significantly inhibit the expressions of the co-stimulatory molecules CD80 and CD86 on DCs and the secretion of IL-12 and the allo-stimulatory activities of DCs were also markedly inhibited. The survival times of allografts in group B of mice were longer than those in group A, while the group C showed the longest survival times of allografts, with a marked reduction in the production of the Th1 type cytokines. It is evident that MMF has a suppressive effect on the maturation and allo-stimulatory activities of the cultured dendritic cell progenitors, thus leading to a donor specific tolerance in heart-transplanted recipients.展开更多
The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificitie...The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificities was manipulated by pulsing different humor of HLA-A2 restricted peptide(s) onto the T2 cells, which acted as stimulating cells to elicit allo-reaction by co-culturing with peripheral blood lymphocytes (PBLs) of HLA-A2 negative individual. Ten HLA-A2 restricted peptides (all were normal cell components ) were synthesized, and cell peptide extract was prepared by frozen and thawed. T2 cells loaded with different number of peptide(s) were co-cultured with PBLs of an HLA-A2 negative individual; the latter were stained with PKH67 in advance. Then the proliferation was monitored with flow cytometry, and the precursor frequency of the effector cells was 'analyzed by the ModFit Software. After 6 d of culture, no proliferation was observed in the bulk culture of PBL alone, and obvious proliferation took place when PBLs of the HLA-A2 negative were co-cultured with T2 cells loaded with or without loading peptide( s). The precursor frequency of the alloreactive CTLs was 0.052 819 for co-culture with T2 cells loaded without peptide; however it was 0. 030 429 for T2 cells with EBV/LMP2A and 0. 030 528 for T2 cells loaded with a single autogeneic peptide, and increased up to 0. 144 942 for T2 cells loaded with 10 autogeneic peptides; the precursor frequency was 0. 203 649 when co-cultured with T2 cells loaded with miscellaneous peptides extracted from the cytoplasm of T2 cells. This study reveals that the precursor frequency of alloreactive CTLs is proportional to the number of T-cell epitope specificities, and independent of the density of the allogeneic HLA Class Ⅰ molecule. Our findings support the hypothesis that the alloreactive T cell populations comprise miscellaneous T cell clones; each is specific to corresponding pMHC. The novel constellation of peptides presented by allogeneic MHC molecules makes thousands of different epitopes, which account for the exceptional high precursor frequency of alloreactive T cells.展开更多
OBJECTIVE: To investigate the proliferation and differentiation of cultured corneal stem cells and determine the effect of corneal stem cells cultured on amniotic membranes on the limbal area for treating corneal burn...OBJECTIVE: To investigate the proliferation and differentiation of cultured corneal stem cells and determine the effect of corneal stem cells cultured on amniotic membranes on the limbal area for treating corneal burns. METHODS: The proliferation and differentiation of corneal stem cells in vitro had been examined using colony-forming efficiency and immunohistochemistry. The stem cells had been cultured on amniotic membranes and transplanted to the limbal area for treating corneal burns. RESULTS: Corneal stem cells had a high proliferation capacity in primary and first passage, cytokeratin 3 was not expressed in primary culture but partly in first passage. The stem cells could proliferate to form cell layer on an amniotic membrane. When transplanted, stem cells could survive on limbus. After transplantation, ocular inflammation resolved, the cornea re-epithelialized, the stromal opacity reduced, the superficial neovascularity was lessened and the conjunctival fornix re-established. CONCLUSIONS: Ocular surface conditions could be improved by allograft of corneal stem cells cultured on amniotic membranes.展开更多
Objective To Investigate stress adaptability of freeze-dried bone allograft.Methods Cortical and cancellous allograft were transplanted to each side of the midshaft diaphyseal ulna in two groups of 28 animals.The left...Objective To Investigate stress adaptability of freeze-dried bone allograft.Methods Cortical and cancellous allograft were transplanted to each side of the midshaft diaphyseal ulna in two groups of 28 animals.The left transplanted allograft was free from fixation and bore a normal physiological lcad,while the right transplanted allograft was protected from loading by a simple external fixator and bore less load.Animals were sacrificed at the 2nd,4th,8th,16th week after transplantation and specimens were taken out for bone histomorphometry studies and analysis of collagen gene expression by in situ Cdna-Mrna hybridization.Results Labeled surface(LS)and bone mineral apposition rate(MAR)of the normally loaded graft-host bone interface were significantly higher than that of the less loaded side at the 4th,8th,16th week after transplantation.Parameters reflecting the internal repair process of the allograft,such as LS in cortical and cancellous bone or MAR in cortical bone of the normally loaded side were significantly higher than those of the less loaded side at the 16th week after transplantation.The result of in situ hybridization indicated that more osteoblast-like cells expressing the type Ⅰ collagen gene were found in the interface or interior of normally loaded grafts.Conclusion The stimulus of physiologic load can accelerate the early union of allograft-host bone interface and later new bone creep substitution to the necrotic allograft.展开更多
Objective: To avoid disadvantages of two-stage cancellus bone autograft, we investigated the feasibility of one-stage allograft for reconstructing the bone defect resulting from debridement of chronic osteomyelitis i...Objective: To avoid disadvantages of two-stage cancellus bone autograft, we investigated the feasibility of one-stage allograft for reconstructing the bone defect resulting from debridement of chronic osteomyelitis in limbs. Methods: Between Feb. 1999 and Apr. 2004, 35 cases of chronic osteomyelitis (8 cases of nonunion ) underwent one-stage allograft after debridement in our hospital. Results: Thirty-five cases were followed up for an average period of 28 months ( range, 13 to 55 months), in which 32 cases (91.43%) were found no infection, and 3 cases (8.57%) were confirmed recurrence of infection. Four out of 8 cases of bone nonunion healed in 9.5 months on average ( range, 3 to 12 months), and another case also acquired union after redebridement and autograft of iliumdue to infection recurrence 35 days after surgery. Renonunion occurred in 3 cases, 2 out of whom healed after secondary operation with autograft. One case of renonunion and 2 cases of infection recurrence refused further treatment. Conclusions: A high rate of infection arrest can be attained when one-stage allograft is used to reconstruct the bone defect of chronic osteomyelitis after debridement in limbs. Therefore, chronic osteomyelitis should not be regarded as a contraindication to one-stage allogeneic bone grafting. Renonuion, however, achieves a relatively high rate, especially in cases of segmental bone defect.展开更多
Objective: To observe the survival of hand allograft under the state of immunosuppression and the pathological changes of rejection in the recovery process. Methods: The biopsies of the skin, nerve, muscle, tendon and...Objective: To observe the survival of hand allograft under the state of immunosuppression and the pathological changes of rejection in the recovery process. Methods: The biopsies of the skin, nerve, muscle, tendon and bone tissue of hand allografts during different stages from 1 day to 7 months after operation were observed using routine histological technique. Results: No significant changes due to rejection in skin, nerve, muscle and bone tissue were observed. But different degrees of weak rejective changes were found on the wall of blood vessels; in the muscle and nerve the reactions were markedly stronger than those found in skin tissues. Conclusions: The rejection in deep tissues should be monitored in controlling the rejection of hand allograft.展开更多
文摘AIM: To study the immuno-modulatory effect of resveratrol (RES) on allograft rejection after liver transplantation in rats. METHODS: Male Sprague-Dawley (SD) rats were selected as donors and male Wistar rats as recipients for a rejection model. The recipients were divided into four groups after orthotopic liver transplantation (OLTx). In the RES A, B, and C groups, RES was given intra-peritoneally once a day (25, 50, and 100 mg/kg, respectively) after OLTx, whereas in the control group, vehicle buffer was given intra-peritoneally once a day. The survival time, serum chemistry, production of cytokines, activation of transcription factor NF-kB, and histopathologic findings were then compared among these groups. RESULTS: The mean survival time after OLTx in the RES C group was significantly longer than that in the control group (16.7+-1.2 d ,vs9.3+-0.6 d, P〈0.01). On the 7th posttransplant day the serum albumin level significantly improved in the RES C group, the serum total bile acid and alanine aminotransferase (ALT) levels were significantly lower in the RES C group, the serum IL-2 and INF-y levels were significantly lower in the RES C group, and the activation of transcription factor NF-kB in peripheral blood T lymphocytes was significantly suppressed in the RES A, B, and C groups in comparison to those in the control group. On the 7^th post-transplant day, a histological examination revealed apparent difference in the severity of rejection between the RES C group and control group. CONCLUSION: RES has an immuno-suppressive property as well as protective effect on hepatocytes under allograft rejection. It might serve as a novel agent for reducing the severity of hepatic allograft rejection in rats.
文摘Objective: To evaluate the functional outcome and complications of allograft replacement in management of bone tumors. Methods: Between March 1992 and September 2002, 164 patients underwent bone tumor resection and massive allograft reconstruction of bone defects. The length of the resected part ranged from 5-35 cm. The resections were classified as marginal or wide resections of the tumor on the basis of the Musculoskeletal Tumor Society staging system. Fresh-frozen allografts were employed as osteoarticular grafts (n = 95), hemi-condylar (n = 15), massive (n = 23), allograft-prosthesis composite (n = 12), intercalary grafts (n = 15) or hemi-pelvic grafts (n = 4). Most of the lesions were osteosarcoma and giant cell tumor of bone and located in proximal and distal femur, proximal tibia and humerus. Results: At a median follow-up of 47 months (range, 12 to 168 months) after the operation, 154 of the patients in the study were free of disease and 10 died of disease. Twenty-one (12.8%) patients had local recurrence and 38 (23.2%) nonunion. Late complications included 11 (6.7%) fractures of the allograft and 18 (11.0%) infections of the graft, instability of the joint in the form of subluxation was noted in 13 (7.9%) patients. Ten extremities were amputated due to local recurrence or severe infection. Conclusion: AIIografts can be used for reconstruction of bony defects after tumor resection. AIIograft has nearly similar shape, strength, osteo-inductivity and osteo-conductivity with host bone. AIIograft implantation is a high complication reconstruction method, and the dsk of recurrence increases when less surgical margin achieves.
文摘Objective.The purpose of this study was to assess the renal graft expression of ICAM 1(intercellular adhesion molecule 1) and LFA 1(lymphocyte function associated antigen 1)molecule with relation to graft rejection. Methods.Rat kidney transplantation was performed according to the procedure of Kamada with some modification.Experimental rats were divided into 5 groups.The survival time of recipient rats and function of grafts after renal transplantation were observed.The sections of renal graft were stained for monoclonal antibody ICAM 1 and LFA 1, and then quantification of ICAM 1 and LFA 1 expression was accomplished by computer image analysis. Results.ICAM 1 and LFA 1 increased significantly in the renal allograft rejection group as compared with the non rejection groups(P<0 05). Conclusion.Both biopsy of renal graft and monitoring of ICAM 1 and LFA 1 are useful tools in diagnosing and treating acute rejection.
文摘The activation of T cells to differentiate and to proliferate is an essential step in the immune response to antigen, especially in cell mediated acute allograft rejection. Besides the interaction of CD3/TCR complex with Ag/MHC complex presented on antigen presenting cells, a complete T cell activation and proliferation requires a second costimulatory signal. The interaction of CD28/CTLA 4 and B7 is a major costimulatory pathway for T Cell activation. Inhibition of this pathway results in development of antigen specific unresponsiveness and clonal anergy.In present study,the biologic function of anti CD28 monoclonal antibody and its Fab fragment were investigated in vitro and in vivo.The results indicate that mAbCD28 and its Fab fragments could promote the functional recovery of allografts and prolong the graft survival,but could not reverse the acute rejection or induce transplantation tolerance in the rat PTG allograft model. We also found that peripheral TNF α level and NK cell activity were suppressed in the presence of mAbCD28 and its Fab fragments for a relatively long time after PTG transplantation.
文摘Objective:To explore the peculiarities of kidney transplantation in elderly patients and define the perioperative managements. Methods: The clinical data of kidney transplantation in 29 patients older than 65years were reviewed, the eldest being 84 years old and the mean age 68. 1 years. Results: Four episodes of acute rejection (13. 80%) were encountered. FK506 toxicity occurred in one case (3.40%) and lung infection in another (3.40%), who (along with the former 4 patients) all were cured subsequently. In one case, the kidney graft was removed for thrombogenesis of the renal artery. The 1- and 3-year patients/grafts survival of 100% and 96.5% respectively was achieved, with the longest survival exceeding 5 years. Conclusions:Old age was not the absolute contraindication for kidney transplantation. Strict observance of the indications of kidney transplantation and donor selection with well-matched tissue-typing are crucial in elderly patients.Adequate application of immunosuppressants and effective long-term follow-up are also major factors for long-term allograft survival.
文摘To investigate the influence of mycophenolate mofetil (MMF) upon the maturation and the allo-stimulatory activity of cultured progenitors of dendritic cells (DCp), and to evaluate the effects of the pre-treated dentritic cells of recipients with MMF on the tolerance induction as well as its possible mechanism, GM-CSF and MMF were added to the in vitro cultured progenitor cells, and the immuno-phenotypical analysis was performed by means of flow cytometry. The secretion of IL-12 was detected by ELISA and the stimulatory activities of DCp on allogeneic T cells were observed by mixed lymphocyte reaction. Twenty-four C57BL/6 mice were divided into 3 groups (each with 8 mice), in which group A of mice accepted allografts of heart from BALB/c mice, group B of mice had received untreated DCp from donors of BALB/c mice 7 days before transplantation, and C57BL/6 mice in group C were treated by injection with MMF-treated allografts of heart from BALB/c mice 7 days before transplantation. The survival times of allografts and the changes of the cytokine levels in sera of the recipient mice were observed after transplantation. The experimental results showed that MMF could significantly inhibit the expressions of the co-stimulatory molecules CD80 and CD86 on DCs and the secretion of IL-12 and the allo-stimulatory activities of DCs were also markedly inhibited. The survival times of allografts in group B of mice were longer than those in group A, while the group C showed the longest survival times of allografts, with a marked reduction in the production of the Th1 type cytokines. It is evident that MMF has a suppressive effect on the maturation and allo-stimulatory activities of the cultured dendritic cell progenitors, thus leading to a donor specific tolerance in heart-transplanted recipients.
基金The work was supported by the grants from the National Natural Science Foundation of China(No.30271201)the Major State Basic Research Development Program of China(No.2001C510008).
文摘The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificities was manipulated by pulsing different humor of HLA-A2 restricted peptide(s) onto the T2 cells, which acted as stimulating cells to elicit allo-reaction by co-culturing with peripheral blood lymphocytes (PBLs) of HLA-A2 negative individual. Ten HLA-A2 restricted peptides (all were normal cell components ) were synthesized, and cell peptide extract was prepared by frozen and thawed. T2 cells loaded with different number of peptide(s) were co-cultured with PBLs of an HLA-A2 negative individual; the latter were stained with PKH67 in advance. Then the proliferation was monitored with flow cytometry, and the precursor frequency of the effector cells was 'analyzed by the ModFit Software. After 6 d of culture, no proliferation was observed in the bulk culture of PBL alone, and obvious proliferation took place when PBLs of the HLA-A2 negative were co-cultured with T2 cells loaded with or without loading peptide( s). The precursor frequency of the alloreactive CTLs was 0.052 819 for co-culture with T2 cells loaded without peptide; however it was 0. 030 429 for T2 cells with EBV/LMP2A and 0. 030 528 for T2 cells loaded with a single autogeneic peptide, and increased up to 0. 144 942 for T2 cells loaded with 10 autogeneic peptides; the precursor frequency was 0. 203 649 when co-cultured with T2 cells loaded with miscellaneous peptides extracted from the cytoplasm of T2 cells. This study reveals that the precursor frequency of alloreactive CTLs is proportional to the number of T-cell epitope specificities, and independent of the density of the allogeneic HLA Class Ⅰ molecule. Our findings support the hypothesis that the alloreactive T cell populations comprise miscellaneous T cell clones; each is specific to corresponding pMHC. The novel constellation of peptides presented by allogeneic MHC molecules makes thousands of different epitopes, which account for the exceptional high precursor frequency of alloreactive T cells.
文摘OBJECTIVE: To investigate the proliferation and differentiation of cultured corneal stem cells and determine the effect of corneal stem cells cultured on amniotic membranes on the limbal area for treating corneal burns. METHODS: The proliferation and differentiation of corneal stem cells in vitro had been examined using colony-forming efficiency and immunohistochemistry. The stem cells had been cultured on amniotic membranes and transplanted to the limbal area for treating corneal burns. RESULTS: Corneal stem cells had a high proliferation capacity in primary and first passage, cytokeratin 3 was not expressed in primary culture but partly in first passage. The stem cells could proliferate to form cell layer on an amniotic membrane. When transplanted, stem cells could survive on limbus. After transplantation, ocular inflammation resolved, the cornea re-epithelialized, the stromal opacity reduced, the superficial neovascularity was lessened and the conjunctival fornix re-established. CONCLUSIONS: Ocular surface conditions could be improved by allograft of corneal stem cells cultured on amniotic membranes.
文摘Objective To Investigate stress adaptability of freeze-dried bone allograft.Methods Cortical and cancellous allograft were transplanted to each side of the midshaft diaphyseal ulna in two groups of 28 animals.The left transplanted allograft was free from fixation and bore a normal physiological lcad,while the right transplanted allograft was protected from loading by a simple external fixator and bore less load.Animals were sacrificed at the 2nd,4th,8th,16th week after transplantation and specimens were taken out for bone histomorphometry studies and analysis of collagen gene expression by in situ Cdna-Mrna hybridization.Results Labeled surface(LS)and bone mineral apposition rate(MAR)of the normally loaded graft-host bone interface were significantly higher than that of the less loaded side at the 4th,8th,16th week after transplantation.Parameters reflecting the internal repair process of the allograft,such as LS in cortical and cancellous bone or MAR in cortical bone of the normally loaded side were significantly higher than those of the less loaded side at the 16th week after transplantation.The result of in situ hybridization indicated that more osteoblast-like cells expressing the type Ⅰ collagen gene were found in the interface or interior of normally loaded grafts.Conclusion The stimulus of physiologic load can accelerate the early union of allograft-host bone interface and later new bone creep substitution to the necrotic allograft.
文摘Objective: To avoid disadvantages of two-stage cancellus bone autograft, we investigated the feasibility of one-stage allograft for reconstructing the bone defect resulting from debridement of chronic osteomyelitis in limbs. Methods: Between Feb. 1999 and Apr. 2004, 35 cases of chronic osteomyelitis (8 cases of nonunion ) underwent one-stage allograft after debridement in our hospital. Results: Thirty-five cases were followed up for an average period of 28 months ( range, 13 to 55 months), in which 32 cases (91.43%) were found no infection, and 3 cases (8.57%) were confirmed recurrence of infection. Four out of 8 cases of bone nonunion healed in 9.5 months on average ( range, 3 to 12 months), and another case also acquired union after redebridement and autograft of iliumdue to infection recurrence 35 days after surgery. Renonunion occurred in 3 cases, 2 out of whom healed after secondary operation with autograft. One case of renonunion and 2 cases of infection recurrence refused further treatment. Conclusions: A high rate of infection arrest can be attained when one-stage allograft is used to reconstruct the bone defect of chronic osteomyelitis after debridement in limbs. Therefore, chronic osteomyelitis should not be regarded as a contraindication to one-stage allogeneic bone grafting. Renonuion, however, achieves a relatively high rate, especially in cases of segmental bone defect.
文摘Objective: To observe the survival of hand allograft under the state of immunosuppression and the pathological changes of rejection in the recovery process. Methods: The biopsies of the skin, nerve, muscle, tendon and bone tissue of hand allografts during different stages from 1 day to 7 months after operation were observed using routine histological technique. Results: No significant changes due to rejection in skin, nerve, muscle and bone tissue were observed. But different degrees of weak rejective changes were found on the wall of blood vessels; in the muscle and nerve the reactions were markedly stronger than those found in skin tissues. Conclusions: The rejection in deep tissues should be monitored in controlling the rejection of hand allograft.