Expansion and characterization of cells from surgically removed intervertebral disc fragments in xenogen-free medium

Low back pain due to degeneration of intervertebral disc (IVD) is a major health problem resulting insignificant disability as well as adding to the economic burden. Discectomy is a very common procedure doneworldwide to relieve this pain. At present all the surgically removed disc tissue is mostly discarded. However,there are reports that state that progenitor cells in the IVD can be grown ex vivo and have the potential to beused for IVD repair and regeneration. We report here that viable cells can be harvested from surgicallyremoved, herniated disc tissue and can be potentially used in cell based therapy. Further, we have successfullyreplaced xenogenic supplements such as foetal bovine serum with either autologous serum or human plateletlysate for culturing IVD cells from patient’s surgically removed disc tissue, without loss of any cell characteristics, including cell surface markers, growth factor secretion in the conditioned medium and osteogenic andchondrogenic differentiation potential in vitro. The present work will not only contribute to overcoming someof the major barriers in carrying out human clinical trials, but also provide a cheap, alternate source of proteinsand growth factors for growing IVD cells ex vivo for therapy

Clinical Evaluation of Regenerative Potential of Xenogenic Bone Grafts in The Treatment of Periodontal Intrabony Defects

The primary goal of periodontal therapy is to restore the tooth supporting tissues lost due to periodontal disease. The aim of the present study was to evaluate the efficacy of xenogenic bone graft with open flap debridement (OFD) in treatment of periodontal intrabony defects. Methods: Twenty intrabony defects were surgically treated. The defects were randomly assigned to treatment with OFD + bone graft (Group B) or OFD alone (Group A). The clinical efficacy of two treatment modalities was evaluated at 9months postoperatively clinically and radiographically. Results: Statistically significant intra group improvements were seen with all the hard tissue and soft tissue parameters in both test and control groups. Statistically significant improvements were seen in group B with clinical parameters and the mean defect fill (AC-BOD) when intergroup comparisons were made. Conclusion: Treatment with bone graft + OFD led to a significantly more favorable clinical outcome in intrabony defects as compared to OFD alone.

Mesenchymal Stem Cells of Different Origin-Seeded Bioceramic Construct in Regeneration of Bone Defect in Rabbit

BACKGROUND: Stem cell is currently playing a major role in the treatment of number of incurable diseases via transplantation therapy. The objective of this study was to determine the osteogenic potential of allogenic and xenogenic bone-derived MSC seeded on a hydroxyapatite (HA/TCP) bioceramic construct in critical size bone defect (CSD) in rabbits. METHODS: A 15 mm long radial osteotomy was performed unilaterally in thirty-six rabbits divided equally in six groups. Bone defects were filled with bioscaffold seeded with autologous, allogenic, ovine, canine BMSCs and cell free bioscaffold block in groups A, B, C, D and E respectively. An empty defect served as the control group. RESULTS: The radiological, histological and SEM observations depicted better and early signs of new bone formation and bridging bone/implant interfaces in the animals of group A followed by B. Both xenogenous MSC-HA/TCP construct also accelerated the healing of critical sized bone defect. There was no sign of any inflammatory reaction in the xenogenic composite scaffold group of animals confirmed their well acceptance by the host body. CONCLUSION: In vivo experiments in rabbit CSD model confirmed that autogenous, allogenous and xenogenous BMSC seeded on bioscaffold promoted faster healing of critical size defects. Hence, we may suggest that BMSCs are suitable for bone formation in fracture healing and non-union.

Application of damage control surgery in treatment of severe electric burn / 实用医学杂志

Objective To explore the effect of damage control surgery (DCS) in the treatment of severe electric burn. Methods Retrospective analysis on clinical data of 45 patients with severe electric burn was con-ducted. According to implementing DCS or not , patients were separated into DCS group and control group. In DCS group, tangential excision and transplanted xenogenic acellular dermal matrix was conducted for severe electric burn cases with deep Ⅱ degree wound, and escharectomy and VSD dressing for Ⅲ~Ⅳ degree electric contact burn wound at the first stage then skin-grafting or skin flap-grafting on the secong stage was applied. For control group , debridement, tangential excision or escharectomy and skin-grafting or skin flap-grafting to close the wound were conducted. We compared the difference in terms of operation time, length of stay, disability rate, mortality and complications between 2 groups. Results The operation time, incidince of disability and complications in DCS Group obviously decreased but there was no difference in length of stay and mortality in both groups. Conclusion DCS is effective for reducing complications and optimizing therapeutic effect for severe electric burn patients.

Innate immunology research of glutaraldehyde-treated xenogenic blood vessels / 中国免疫学杂志

Objective:To conduct a systematic study of the immunologic response of rats to transplanted glutaraldehyde ( GA)-treated porcine blood vessels in vivo.Methods: The experiment was divided into two groups:fresh group and glutaraldehyde-treated group.Twenty cases of fresh and glutaraldehyde-treated porcine pulmonary arteries were subcutaneously embedded in rats.We compared the changes using HE staining and immunohistochemistry.Results:HE staining showed that there were stronger expression on day 12 and day 30 in the fresh group than that in the glutaraldehyde group.There were similar results in morphology in CD68,C3,IgG.The results of integral optical density ( IOD) in immunohistochemistry showed that IOD started rising from day 4 and got the peak on day 12 or day 30 and or fell on day 60.Conclusion: Innate immunity played an important role in the research on xenogenic immunological rejection mechanism.The immunogenicity of glutaraldehyde-treated xenogenic blood vessels is lower than that in fresh blood vessels.However there is still immunogenicity in glutaraldehyde-treated xenogenic blood vessels.We will explore better ways to obviously weaken the rejection.

Avaliação da remodelação do rebordo alveolar após exodontia minimamente traumática e utilização de enxerto xenógeno para preservação alveolar / Dimensional changes of alveolar bone in extraction sockets, after minimally traumatic extraction and socket fill with xenogenic bone

Introdução: Após a exodontia, a cicatrização natural do alvéolo provoca alterações dimensionais no rebordo alveolar, com diminuição dos tecidos moles e duros. Diferentes técnicas podem ser utilizadas para tentar diminuir essas alterações, com a intenção de facilitar a reabilitação estética e funcional com implantes, principalmente em áreas de dentes anteriores. Objetivos: Os objetivos deste estudo foram verificar a eficácia da utilização do material de origem xenógena Orthogen® na preservação do rebordo alveolar pós-exodontia e avaliar as características histológicas após 4 meses de reparo. Materiais e Métodos: 20 pacientes foram divididos aleatoriamente em 2 grupos, de acordo com a abordagem que iriam receber após a exodontia de uma raiz residual. No grupo teste, os alvéolos foram preenchidos com Orthogen® e selados com EGL (Enxerto Gengival Livre). No grupo controle, um coágulo foi preservado no alvéolo e o mesmo também foi selado com EGL, sem a utilização do Orthogen®. Em ambos os grupos as exodontias foram realizadas de maneira minimamente traumática, com o Kit de Extração Atraumática Neodent®. Modelos de gesso obtidos antes das exodontias (tempo 1) e após 4 meses (tempo 2), momentos antes da instalação dos implantes, foram utilizadas para as medidas dimensionais, através do escanemento dos modelos e medidas no programa Orthoanalyzer®. Amostras ósseas obtidas após 4 meses de reparo foram utilizadas para a análise histológica descritiva. Resultados: Os resultados demonstraram que, após 4 meses de reparo alveolar, os dois grupos apresentaram remodelação do rebordo alveolar e diminuição nas medidas realizadas. Porém, a remodelação do rebordo foi mais evidente no grupo controle (coágulo). Histologicamente foi possível observar formação de novo osso ao redor das partículas do Orthogen®. Conclusões: A utilização do Orthogen® para preenchimento dos alvéolos e preservação do rebordo alveolar foi eficaz na diminuição...

Introduction: After tooth extraction, the natural healing of the socket is followed by dimensional changes of ridge contour, with marked reduce of hard and soft tissues. Socket reservation techniques can be used to improve functional and esthetics of the dental implants in this areas, especially in anterior teeth areas. Objectives: The aims of this study are to verify the efficacy of use Orthogen® to ridge preservation and analysis the histological characteristics after 4 months repair of the sockets. Material and Methods: 20 patients were randomly distributed in 2 groups, according with the treatments. In test group, the sockets were filled with Orthogen® and closed with a gingival free graft. In control group, the clots were preserved into the socket and free gingival graft was sutured in the deepithelialized marginal tissue of the socket. Stone casts were used to analyze the ridge dimensional changes with the Orthoanalyzer® software. After 4 months, bone samples were obtained during the dental implant procedure and were used to describe the histological characteristics. Results: The results showed that, after 4 months of wound healing, both groups showed a decrease in the measurements. However, the remodeling of the ridge was most evident in the control group (clot). Histological images showed the formation of new bone around the Orthogen® particles. Conclusion: The use of Orthogen® to socket preservation can collaborate to reduce the dimensional changes of the hard and soft tissue in post-extraction alveolar ridge sites...

Avaliação da remodelação do rebordo alveolar após exodontia minimamente traumática e utilização de enxerto xenógeno para preservação alveolar / Dimensional changes of alveolar bone in extraction sockets, after minimally traumatic extraction and socket fill with xenogenic bone

Introdução: Após a exodontia, a cicatrização natural do alvéolo provoca alterações dimensionais no rebordo alveolar, com diminuição dos tecidos moles e duros. Diferentes técnicas podem ser utilizadas para tentar diminuir essas alterações, com a intenção de facilitar a reabilitação estética e funcional com implantes, principalmente em áreas de dentes anteriores. Objetivos: Os objetivos deste estudo foram verificar a eficácia da utilização do material de origem xenógena Orthogen® na preservação do rebordo alveolar pós-exodontia e avaliar as características histológicas após 4 meses de reparo. Materiais e Métodos: 20 pacientes foram divididos aleatoriamente em 2 grupos, de acordo com a abordagem que iriam receber após a exodontia de uma raiz residual. No grupo teste, os alvéolos foram preenchidos com Orthogen® e selados com EGL (Enxerto Gengival Livre). No grupo controle, um coágulo foi preservado no alvéolo e o mesmo também foi selado com EGL, sem a utilização do Orthogen®. Em ambos os grupos as exodontias foram realizadas de maneira minimamente traumática, com o Kit de Extração Atraumática Neodent®. Modelos de gesso obtidos antes das exodontias (tempo 1) e após 4 meses (tempo 2), momentos antes da instalação dos implantes, foram utilizadas para as medidas dimensionais, através do escanemento dos modelos e medidas no programa Orthoanalyzer®. Amostras ósseas obtidas após 4 meses de reparo foram utilizadas para a análise histológica descritiva. Resultados: Os resultados demonstraram que, após 4 meses de reparo alveolar, os dois grupos apresentaram remodelação do rebordo alveolar e diminuição nas medidas realizadas. Porém, a remodelação do rebordo foi mais evidente no grupo controle (coágulo). Histologicamente foi possível observar formação de novo osso ao redor das partículas do Orthogen®. Conclusões: A utilização do Orthogen® para preenchimento dos alvéolos e preservação do rebordo alveolar foi eficaz na diminuição das...

Introduction: After tooth extraction, the natural healing of the socket is followed by dimensional changes of ridge contour, with marked reduce of hard and soft tissues. Socket reservation techniques can be used to improve functional and esthetics of the dental implants in this areas, especially in anterior teeth areas. Objectives: The aims of this study are to verify the efficacy of use Orthogen® to ridge preservation and analysis the histological characteristics after 4 months repair of the sockets. Material and Methods: 20 patients were randomly distributed in 2 groups, according with the treatments. In test group, the sockets were filled with Orthogen® and closed with a gingival free graft. In control group, the clots were preserved into the socket and free gingival graft was sutured in the deepithelialized marginal tissue of the socket. Stone casts were used to analyze the ridge dimensional changes with the Orthoanalyzer® software. After 4 months, bone samples were obtained during the dental implant procedure and were used to describe the histological characteristics. Results: The results showed that, after 4 months of wound healing, both groups showed a decrease in the measurements. However, the remodeling of the ridge was most evident in the control group (clot). Histological images showed the formation of new bone around the Orthogen® particles. Conclusion: The use of Orthogen® to socket preservation can collaborate to reduce the dimensional changes of the hard and soft tissue in post-extraction alveolar ridge sites.

Comparison of the biocompatibility of three kinds of antigen-extracted xenogeneic cancellous bone matrices / 中国组织工程研究

BACKGROUND:The form and structure of antigen-extracted xenogeneic cancel ous bone through series of physical and chemical treatment are similar to human tissue. OBJECTIVE:To detect the biocompatibility of antigen-extracted xenogeneic cancel ous bone matrix prepared by three different ways. METHODS:The antigen-extracted xenogeneic cancel ous bone scaffold materials which were prepared through physical, chemical and physical-chemical combined methods and hydroxy apatite biological ceramic materials were implanted into the dorsum subcutaneous tissue. Histological observation was done at 4, 8 and 12 weeks after surgery. The antigen-extracted xenogeneic cancel ous bone scaffold materials which were prepared through physical, chemical and physical-chemical combined methods respectively was used to culture sheep bone marrow mesenchymal stem cells for 7 days. Cel adhesion, growth, proliferation and stroma secretion were observed. RESULTS AND CONCLUSION:At 4 weeks after surgery, a strong inflammatory reaction was detected around materials in four groups. At 12 weeks, the xenogeneic bone materials prepared through physical and physical-chemical combined methods and hydroxy apatite biological ceramic materials internal pore and surrounding tissue inflammation disappeared basical y, with the presence of thimbleful inflammation cells. The material degradation was more than at 8 weeks. The xenogeneic bone materials prepared through chemical methods material internal pore and surrounding tissue inflammation stil existed, suggesting that the xenogeneic bone materials prepared through physical and physical-chemical combined methods exhibited good histocompatibility. A smal amount of orderly osteoblasts existed around hydroxy apatite biological ceramic materials and physical-chemical prepared materials, with a smal amount of bone. These suggested that there was a tendency for ectopic bone formation. The xenogeneic cancel ous bone materials prepared through physical or physical-chemical combined methods have better cytocompatibility. However, scaffold materials prepared through chemical method have poor cytocompatibility and they are not qualified for the safety standards of biological materials.

Histocompatibility of noval xenogenic tendon matrix materials / 中华医学美学美容杂志

Objective To evaluate the histocompatibility of novel manufactured xenogenic tendon matrix materials by an animal experimental study.Methods The study was conducted on 15 dogs,weighing 10-13 kg.The prepared xenogenic tendon matrix materials were implanted into the bilateral area of spine in dogs subcutaneously (experimental group),and the implantation of silicon served as control group.The animals were killed 14,30,60 days after surgery and the specimens were processed in laboratory to receive gross and histology observation.The histological sections were stained with hematoxylin-eosin and analyzed by light microscopy.Scores were assigned to the inflammatory process and statistically compared by two related samples with non-parametric test.Results All dogs survived well during the embedded test.There was no tissue necrosis,effusion or inflammation at all implantation sites in both groups during the test.The xenogenic implant materials promoted slight to moderate inflammation process after 14 days,with no statistically significant difference compared to the control.However,after 30 days,there was a regression of inflammation.After 60 days,it was observed the presence of well-organized connective tissue,and few inflammatory cells.Score evaluation of inflammation response at different time after operation of two groups showed no statistically significant difference (P＞0.05).Conclusions The new xenogenic tendon matrix materials are considered biocompatible with subcutaneous tissue.

Restoration of Calvarial Defect Using a Variety of Xenogenous Tooth Bone Graft Material: Animal Study

Compare of the capability of optimized acellular allograft and xenograft reparing rat sciatic nerve defect / 中华显微外科杂志

ObjectiveTo compare the capability of optimized acellular(OA) allograft and xenograft reparing rat sciatic nerve defect by observing the immunological rejection, early functional recovery and nerve regeneration in the adult rats, which had been made a 1.0cm long gap in the continuity of the sciatic nerve.MethodsThe right sciatic nerve of adult Sprague-Dawley(SD) rats were exposed and 1.0cm long segment of the nerves were removed and repaired by fresh rabbit nerve and autofrafts, OA rat and rabbit nerve. After 1 and 3 months respectively,sciatic functional index (SFI),electrophysiological and histology studies were detected to evaluate immunological rejection,early functional recovery and nerve regeneration. ResultsThe immunological rejection, functional recovery and nerve regeneration in OA xenografts were compared with that in OA allografts, autografts and fresh allografts. One month after the surgery, the levels of CD8+ T cells and macrophages that infiltrated the grafts,the SFI and the axon density at the midpoints of them were similar within OA grafts and autografts(P ＞ 0.05),but all statistically distinguishable from fresh allografts(P ＜ 0.05).And better results were got after 2 months(P ＜ 0.05).ConclusionsThe results imply that OA xenografts is as good as OA allografts,which can be immunologically tolerated and that the removal of cellular material and preservation of the matrix are beneficial for promoting regeneration and functional recovery through an OA procedure.And this gives another promising option to repair peripheral nerve defect.

Immunomodulatory effect of canine periodontal ligament stem cells on allogenic and xenogenic peripheral blood mononuclear cells

PURPOSE: The aim of this study was to investigate the immunomodulatory effects of canine periodontal ligament stem cells on allogenic and xenogenic immune cells in vitro. METHODS: Mixed cell cultures consisting of canine stem cells (periodontal ligament stem cells and bone marrow stem cells) and allogenic canine/xenogenic human peripheral blood mononuclear cells (PBMCs) were established following the addition of phytohemagglutinin. The proliferation of PBMCs was evaluated using the MTS assay. The cell division of PBMCs was analyzed using the CFSE assay. The apoptosis of PBMCs was assessed using the trypan blue uptake method. RESULTS: Periodontal ligament stem cells and bone marrow stem cells inhibited the proliferation of allogenic and xenogenic PBMCs. Both periodontal ligament stem cells and bone marrow stem cells suppressed the cell division of PBMCs despite the existence of a mitogen. No significant differences in the percentages of apoptotic PBMCs were found among the groups. CONCLUSIONS: Canine periodontal ligament stem cells have an immunomodulatory effect on allogenic and xenogenic PBMCs. This effect is not a product of apoptosis of PBMCs but is caused by the inhibition of cell division of PBMCs.

Avaliação radiográfica, biomecânica e microscópica de enxerto ósseo xenogênico associado a implantes de titânio em mandíbula de coelhos / Radiographic, biomechanical and microscopic evaluation of xenogenic bone graft associated to titanium implants in rabbits mandible

O propósito deste trabalho foi avaliar a interação de matriz óssea bovina inorgânica, (Gen-ox®) como material de enxerto e implantes de titânio em mandíbula de coelhos. A amostra constituiu-se de 32 coelhos da raça Botucatu de aproximadamente 4kg. Os incisivos inferiores destes animais foram extraídos e foi realizada um defeito de aproximadamente 4mm de diâmetro. Um dos lados foi mantido apenas com coágulo (grupo controle) e o outro lado (grupo experimental) recebeu o enxerto do material proposto. Após 60 dias foram instalados implantes bilateralmente na região do defeito. Os animais foram eutanaziados imediatamente após a instalação dos implantes e após 1, 2 e 6 meses (n=6) para o grupo microscópico a após 2 e 6 meses para o grupo do teste biomecânico (n=4). A análise constituiu de medidas da distância da crista óssea alveolar à plataforma do implante, da densidade radiográfica em valores de pixel ma região do alvéolo, de teste biomecânico de torque de remoção e microscópico através de medidas de contato osso-implante (BIC) (em µm e %) e área de osso (em µm² e %). Os resultados demonstraram que não houve diferenças significantes nem durante o tempo e nem entre os grupos na analise de distancia entre crista óssea alveolar e plataforma do implante. Na medida de densidade óssea, não houve variação significante ao longo do tempo, mas houve diferença estatisticamente significante entre os grupos, sendo maior no grupo experimental. Para o teste biomecânico também não houve variação significante do torque de remoção ao longo do tempo e nem houve diferença significante entre os grupos. Na análise de contato osso implante (BIC) não houve variação significante ao longo do tempo, mas houve diferença estatisticamente significante entre os ...

The aim of this study was to evaluate the interaction of an inorganic bovine bone matrix (Gen-ox®) as bone graft and titanium implants in rabbits mandible. Thirty-two Botucatu rabbits weighting about 4kg were used on this experiment. The mandible incisives were extracted and a defect of 4 mm of diameter was performed. One socket and defect was filled with experimental material. The opposite site was left to heal naturally and served as control. After 60 days, the implants were installed on the defect region. The animals were killed immediately after the implant installation and after 1, 2 and 6 months. Vertical bone height, bone density, biomechanical test, bone implant contact (BIC) and bone area near to implant threads were evaluated. The results showed that there was no significant differences on the distance between the alveolar bone crest to the implant platform (vertical bone height) along the time, neither between groups. On the bone density (pixel value) there was no significant difference along the time, but there was significant difference between groups, being the experimental group higher. For the biomechanical test there was no significant difference along the time, neither between groups. There was no significant differences on the bone implant contact (BIC) measures along the time, but there was significant difference between groups, being the experimental groups higher and there was interaction between time and groups. On bone area evaluation, there was no significant difference along the time, neither between the groups during the analyzed time. The graft behavior observed by the authors was similar to that of the control group, suggesting high acceptance of the material as graft option associated to titanium implants.

Application of armor plate and xenogenic bong plate in treatment of congenital pseudarthrosis of the tibia / 中国矫形外科杂志

[Objective]To evaluate curative effect of armor plate and xenogenic bony plate in congenital pseudarthrosis of the tibia.[Method]Five cases of congenital pseudarthrosis of the tibia were reviewed from 1998 to 2004,there were 2 men and 3 women,average age was 5.8(ranged,3~10)years.All the patients were treated by armor plate and xenogenic bony plate.[Result]All of the patients were followed up for more than 3 years(from 3 years to 7 years),four cases achieved bony union.Average time of bony union was 5 months.The lower limbs resumed walking ability and bear a heavy burden.[Conclusion]Outcome of 4 patients demonstrates that treatment of congenital pseudarthrosis of the tibia with armor plate and xenogenic bony plate is a reliable treatment.

Research of immunoreaction of heterogeneic articular cartilage extracellular matrix derived scaffold / 中国矫形外科杂志

0.05).[Conclusion]Porcine articular cartilage extracellular matrix derived scaffold used in heterogenic transplantation or allograft have no immunologic rejection.This research provides a feasibility for application of xenogenic acellular cartilage to clinic.

A Comparative Study of the effects of Autogenous and Xenogenic Bone grafts with PRP(Platelet Rich Plasma) technique on Periodontal Regeneration / 대한치주과학회지

Regeneration of Periodontium with PRP does not only improve regeneration rate and density of bone but have a possibility to estimate faster healing process for soft tissue. And also, autogenous bone and xenogenic bone graft are effective on regeneration of periodontium. The purpose of this study is to evaluate the effectiveness of autogenous bone and xenogenic bone (BBP(R)) grafts with the PRP technique on regeneration of periodontium. 52 Generally healthy Pt. who had pocket depth 5mm at any of 6 surfaces of the teeth were in the study at Dept. of Perio. in Dankook Dental Hospital. Open Flap was treated for 18 infra-bony pockets as control group, autogenous bone with PRP was inserted for 25 infrabony pockets as first test group, and BBP(R) with PRP was inserted for 22 infrabony pockets as 2nd test group. Then evaluation was made after 3 and 6 months 1. There were significant differences between average probing pocket depth and clinical attachment level of 3, 6 months and minimal and maximal attachment level after 6 months each other. 2. There were significant differences in average probing pocket depth of control group and 2nd experimental group between 1 and 6 months. For clinical attachment level and minimal and maximal proving attachment level, there was a significant difference after 6 month of surgery. 3. There was no significant difference between two test groups for average probing depth, clinical attachment level, and minimal and maximal probing attachment level. As the result, PRP with bone graft could be very effective for regeneration of periodontium and there was no difference between xenogenic bone and autogenous bone.

The Effects of Calcium-Phosphate Coated Xenogenic Bone and Type I Collagen for Bone Regeneration on the Calvarial Defects in Rabbits / 대한치주과학회지

No abstract available.

Effect of cytotoxicity T lymphocyte on acute rejection of xenogenic liver transplantation / 中国普通外科杂志

Objective To study the mechanism of cytotoxic T lympocytes in the acute rejection of xenogenic liver transplantation(XLT). Methods Hamster to rat orthotopic liver transplantation model was performed with three cuff method. In XLT,lymphocytes including CD8 and CD4 subsets were observed by histology and immunohistochemistry; the expression of perforin and Fas- L was observed by immunohistochemistry; and apoptotic cells of XLT were observed in situ end-labelling of fragmented DNA. Results In the XLT, T cell infiltration firstly ocurred on the 2nd day posttansplantation and located at the portal triads; the infiltrating lymphocytes proliferated increased with time and reached the peak on the 5th to 6th days.Perforin and Fas-ligand were expressed on the 4th day after XLT, and peaked on the 5th to 6th day,and the expression of perforing was still higher than the expression of Fas-ligand. Conclusions T lymphocyte participates in the acute rejection of XLT through the expression of perforin and Fas-ligand, which leads to apoptosis or necrosis of hepatocytes.

Enhanced MHC I antigen expression on tumour target cells is inversely correlated to lysis by allogenic but not by xenogenic NK cells.

Relationship between the levels of MHC class 1 antigen expressed on tumour cells and their susceptibility to allogenic and xenogenic NK cells was investigated. Mouse and human natural killer-resistance inducing factor (NK-RIF) preparations were used for augmenting/inducing MHC 1 antigen expression on murine YAC and human K562 tumour cells, respectively YAC cells with augmented MHC I antigen expression became relatively resistant to lysis by murine NK cells but not to rat NK cells. Similarly, induction of MHC I antigens on K562 cells reduced their susceptibility to human NK cells but not to monkey NK cells. These results indicate that the inverse correlation of MHC I antigen expression and NK susceptibility does not hold true for xenogenic pairs of NK effector and target cells.

The Problems of The Vessel Rebuilding in Fresh Xenogenic Bone Graft with Glucocoticoid Used for A Short Period of Time / 昆明医科大学学报

With Indian ink vasoperfusion and microangiography,the vessel rebuilding in fresh xenogenic bone graft of 33 rabbits,which had been given glucocortiocoid for a short period of time has observed.The results were as follows:(1)The vessel rebuilding ofxenogenic bone marrow was formed by the hostbone vessel growing in, however,that of the compact bone was formed by the inward penetration of the vessels from the host periost.(2)with glucocorticoid having been used for a short period of time,the vessel rebuilding rate was almost the same between fresh xenogenic bone and autogenic bone.(3)Vessel invasion which happened before osteogenesis regulated osteogenic action. The vessel invasion of different or- igins and under different conditions may have different influence on osteogenesis and osteolysis.