Biomedical subjects

Guo-Xian Pei

Publications and source records attributed to Guo-Xian Pei.

15 recordsLinked to original sources

PubMed2005

[Optical, scanning electron and atomic force microscopic observation of the microstructure of human humeral bone].

OBJECTIVE: To observe the microstructure of human long bone with scanning electron and atomic force microscopes to understand the ultrastructural organization and the composition and the morphology of the bone collagen and minerals. METHOD: Fresh human cadaveric humeral bone were fixed and dehydrated to prepare the ground sections and thin slices, respectively, which were observed for bone microstructure using optical, scanning electron and atomic force microscopy, respectively. RESULTS: Under optical microscope, the bone lacunae were in circular permutation around the Haversian canal, and the canaliculi communicated the lacunae and Haversian canal or between the lacunae. Atomic force microscopy represented distinct morphology of the large clusters of collagen, and the collagen fibers thickened in the mineralized zone and appeared in the shape of overlapping discs, whereas the calcium-phosphorus crystal displayed ellipse cylinders. The size, shape and relation of the canaliculi and lacunae were observed clearly. The bone matrix was observed in circular arrangement along the Haversian canal and the calcium-phosphorus crystal was in regular alignment under scanning electron microscope. CONCLUSION: Atomic force microscopy can help analyze the three-dimensional configuration of calcium-phosphorus crystal and bone collagen as well as the canaliculi and lacuna. The canaliculi serve as the channels mediating alimentation and molecular signals into the lacuna.

Collagen↗

PubMed2004

Serial monitoring of immunological parameters following human hand transplant.

BACKGROUND: Although early successes have been achieved in human hand transplant, the changes of immunological parameters in the recipients and their relations to clinical events were not yet known. METHODS: In two patients undergoing hand transplantation, we prospectively determined lymphocyte subsets using flow cytometry as well as the serum levels of interleukin (IL)-2, IL-10, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma using enzyme linked immunosorbent assays during the first 6 months after transplantation. RESULTS: The decreases in CD, CD, CD T cell, the activated T cell (CD/CD, CD/HLA-DR(+)) as well as IL-2, IFN-gamma and corresponding significant peak in IL-10 in human hand transplant during the first post-transplant week were observed. Then these parameters recovered to the pre-transplant level except for an even higher level of CD T cell. The low CD/CD ratio was been maintained constantly. After 7 wk, IL-2, IFN-gamma, and IL-10 decreased to be maintained at a low or undetectable level except for slight increase in IL-10 at post-transplant month 5. There are no significant variation in TNF-alpha early after transplant. After 3 months, IL-10 was not detected again. CONCLUSIONS: The immunosuppressive agents had significantly effects on the immunological status in human hand transplant recipients. These profiles of immunological parameters would be useful data for the future immunomonitoring in human hand transplant recipients.

Adult↗

PubMed2002

[Peripheral nerve regeneration under immunosuppression].

OBJECTIVE: To discuss peripheral nerve regeneration under immunosuppression. METHODS: Current research trends about relationship between peripheral nerve injury and immunoreaction, the experimental result of nerve regeneration after using various immunosuppressors, and the clinical findings after human allogenous hand transplantation were extensively reviewed. RESULTS: Peripheral nerve regeneration was accelerated under immunosuppression. CONCLUSION: Peripheral nerve injury may induce immunoreaction, which inhibit nerve regeneration and function recovery.

Cyclosporine↗

PubMed2002

Changes of serum MDA and SOD levels in ischemia-reperfusion injuries of the limbs in rats preconditioned with heat stress.

OBJECTIVE: To study the effect of pretreatment with heat stress on ischemia-reperfusion injuries of the limbs in rats. METHODS: Rat models of ischemia-reperfusion injury were established with or without prior heat stress treatment, in which serum malondialdehyde (MDA) level and superoxide dismutase (SOD) activities were measured by means of thiobarbituric acid and nitroblue tetrazolium respectively. RESULTS: Comparison between ischemia-reperfusion group and the control group revealed significantly elevated MDA levels (P<0.01) and depressed SOD activities (P<0.01) in the condition of ischemia-reperfusion injury. Pretreatment with heat stress, however, significantly lowered the elevated MDA levels (P<0.01) and enhanced SOD activities (P<0.01) during ischemia-reperfusion injury. CONCLUSION: Pretreatment with heat stress can enhance the activity of SOD to remove free oxygen radicals in the cells.

Animals↗

PubMed2002

Effect of X-ray irradiation on limb allograft rejection in adult rats.

OBJECTIVE: To establish appropriate animal models for observing the effects of X-ray irradiation on limb allograft rejection. METHODS: Wistar rats were used as donators and SD rats as recipients, the latter divided into 2 groups, namely irradiation group and non-irradiation group according to pretransplant treatment with or without X-ray radiation (5 Gy) on the part of the donators. The donor limbs were transplanted into SD rats who had their own limbs cut off, and the sciatic nerve, femoral nerve, and femoral artery and femoral vein were anastomosed in operation. After the operation, all the recipients were given benzathine benzylpenicillin, and their vital signs, together with changes of the allografts, observed. RESULTS: A total of 16 rats received transplantation that was successful in 6 rats of non-radiation group and 7 of irradiation group. The graft survival averaged 12.0+/-2.4 d in non-irradiation group and 24.7+/-8.1 d in irradiation group, showing significant difference in the lengths of survival between the 2 groups (P<0.05). CONCLUSION: The graft survival time in rats can be significantly prolonged by pretransplant irradiation of the allograft, which also help control acute rejection of the allograft.

Animals↗

PubMed2002

Effect of pretreatment with adenosine, diazoxide or ischemic preconditioning on ischemia- reperfusion injury in the limbs of rats.

OBJECTIVE: To study the effect of ischemic preconditioning (PC) and pharmacological preconditioning with adenosine or diazoxide on ischemia-reperfusion (IR) injury in the limbs of rats. METHODS: According to different treatment received before ischemic-reperfusion injury, 66 SD rats were divided into 6 groups including a normal control and a ischemia-reperfusion control group, IP10 group in which the rats received 10-min ischemia followed by 10-min interval for reperfusion for 3 times before IR, IP5 group in which the rats were subjected to 5-min ischemia with 5-min reperfusion intervals for 3 times before IR, adenosine (Ade) pretreatment group and diazoxide (Dia) pretreatment group. Except the normal control group, which consisted of 6 rats, each group contained 12 rats, and IR injury was induced by blocking the blood flow in bilateral limbs for 4 h, followed by reperfusion for 2 or 24 h when twitch and spastic contractility of the tibialis anterior muscle and serum creatine phosphokinase (CPK) were measured. RESULTS: In IP5 and Ade pretreatment group, the twitch tension of the tibialis anterior muscle of the rats was significantly enhanced after 2 and 24 h of reperfusion, achieving the level of the normal control. The twitch tension was also enhanced in rats of IP10 group at 24 h, but at 2 h, though with less effectiveness than that in IP5 and Ade group. Dia pretreatment reduced twitch and tetanic contraction forces of the tibialis anterior muscle after 2 h of reperfusion, but obviously improved twitch tension at 24 h. Improvement in the tetanic tension, however, was seen in none of the groups. Serum CPK of IP5, IP10 and Ade groups after 2 and 24 h while Dia at only 24 h of reperfusion was obviously lower than that of IR group. CONCLUSIONS: Ischemic and Ade preconditioning can protect the limbs of rats from ischemia-reperfusion injury, and Dia has delayed protective effect. IP5 is superior than IP10 and Ade PC can produce similar effect to that of ischemic PC.

Adenosine↗

PubMed2002

[mRNA expression of recombinant human bone morphogenetic protein 7 in skeletal muscle satellite cells with retroviral vector-mediated rhBMP7 gene transfection].

OBJECTIVE: To detect the expression of recombinant human bone morphogenetic protein7 (rhBMP7) in skeletal muscle satellite cells (SMSCs) with rhBMP7 gene transfection mediated by retroviral vector. METHODS: rhBMP7 gene was reconstructed in retroviral vector and transferred into packaging cells PT67 via liposome reagent, with the positive cell clones selected with G418. In vitro cultured SMSCs were transfected with the virus granules secreted by PT67 cells and followed by G418 selection. Reverse transcriptase-polymerase chain reaction was utilized for analysis for rhBMP7 mRNA in the transfected cells. RESULTS: rhBMP7 retrovirus vector was successfully constructed and transferred into PT67 cells, and abundant mRNA expression of rhBMP7 was observed in the skeletal muscle satellite cells transfected with the virus and selected with G418. CONCLUSION: rhBMP7 gene can be transferred into the skeletal muscle satellite cells via retroviral vector to yield effective rhBMP7 mRNA expression.

Animals↗

PubMed2002

[Dynamic changes of SOD and MDA in canine limbs with gunshot wound in hot and humid environment: an experimental study].

OBJECTIVE: To study the dynamic changes in lipid peroxidation and the activity of antioxidative enzyme in canine limbs with gunshot wound in hot and humid environment. METHODS: Eighteen dogs with gunshot wound were randomly assigned into 3 groups with equal numbers. Dogs observed after injury in normal environment was designated as NE group, those in hot and humid environment as HHE group and those in hot and humid environment with preceding heat acclimatization training as HA group. Contents of superoxide dismutase (SOD) and malonaldehyde (MDA) in both the peripheral blood and muscular tissues from gunshot wound tract were measured at 0, 1, 3, 4, 6, 8, 10, 14, 18 and 24 h respectively after the dogs had been wounded. RESULTS: Positive correlation between SOD and MDA contents was observed in each group. Three hours after injury, MDA level in HHE group began to ascend, reaching the peak level at 6 h that was significantly higher than those in the other 2 groups (P<0.05); SOD level underwent a reverse change, which was significantly lower in HHE group than in the other groups with that in HA group being the highest. Comparable SOD levels in the groups occurred at the time of 14 h, which happened to MDA levels 4 h later. CONCLUSION: Gunshot injuries in the limbs of dogs exposed to hot and humid environment induces increased free oxygen and aggravated the lipid peroxidation, which can be alleviated by heat acclimatization.

Animals↗

PubMed2002

[Expression of human bone morphogenetic protein 7 mRNA after the gene transfection in rabbit bone marrow-derived mesenchymal stem cells].

OBJECTIVE: To detect the expression of human bone morphogenetic protein 7 (hBMP-7) mRNA in rabbit bone marrow-derived mesenchymal stem cells with hBMP-7 gene transfection mediated by retroviral vector. METHODS: Retroviral vector for hBMP-7 gene was constructed that was transferred into the packaging cell PT67 mediated by liposome. hBMP-7 gene-positive cell clones were selected with G418 (600 ng/ml) and amplified to obtain the retroviral supernatant containing the target genes that were subsequently used to transfect rabbit bone marrow-derived mesenchymal stem cells (MSCs). HBMP-7 mRNA expression in the MSCs was examined by way of in situ hybridization and reverse transcriptase-polymerase chain reaction. RESULTS: hBMP-7 retroviral vector was successfully constructed and transferred into PT67 cells with resistance to G418, and after transfection with the recombinant retrovirus, transcription and expression of hBMP-7 mRNA were detected in MSCs. CONCLUSION: Rabbit bone marrow stem cells transfected with hBMP gene via retroviral vector can secrete the correspondent protein, indicating the possibility of enhancing the osteogenic capacity of MSCs in the study of bone tissue engineering.

3T3 Cells↗

PubMed2002

[Bacterium culture and flora analysis of gunshot wound on limbs of dogs in hot and humid environment].

OBJECTIVE: To investigate the time of bacterial invasion into the blood and conduct flora analysis of the blood and secretions in the gunshot wound in the limbs of dogs in hot and humid environment. METHODS: Gun-shot wound was induced in 8 dogs who were subsequently assigned at random into hot and humid environment (HHE) group and normal environment (NE) group for observation. At the time points of 0, 4, 6, 8, 12, 24 h after injury, body temperature was measured and bacterial culture and flora analysis performed. RESULTS: Body temperature elevation occurred earlier and lasted for longer time in HEE group than in NE group. Bacterial invasion into the blood occurred at 12 h after the injury in NE group, but at 8 h in HHE group. In the wound tracts of the dogs, surface bacteria were found in both groups. Surface bacteria were also found in the blood of dogs in both groups, but in HHE group, even intestinal flora were identified. CONCLUSION: Body temperature elevation and bacterial invasion into the blood occurred at an earlier time in hot and humid environment where migration of intestinal bacteria into the blood easily takes place, indicating the early application of broad-spectrum antibiotics under such environmental conditions.

Animals↗

PubMed2002

[Repair of tibial defect with tissue-engineered bone graft and radionuclide bone imaging in goats].

OBJECTIVE: To observe the effect of tissue-engineered bone grafts in repairing large tibial defect in goats, and assess the value of radionuclide bone imaging in monitoring the therapeutic effect of this approach. METHODS: Tibial defects measuring 2 cm was artificially made in the left tibia of 27 normal goats that were subsequently divided into 3 groups (9 each) to undergo treatment with tissue-engineered bone grafts, artificial bone grafts or without any grafts (as control group) respectively. The tissue-engineered bone grafts contained bone marrow stroma cells (BMSCs) of the goats and coral hydroxyapatite (CHAP), while the artificial bone grafts were from CHAP only. After the operations, radionuclide bone imaging was used to monitor the therapeutic effects at 2, 4 and 8 postoperative weeks. RESULTS: The 99mTc-MDP uptake of the region of interest (ROI) and the target to non-target ratios (T/NT) of the control group did not indicate any process of revascularization or bone regeneration. An increasing tendency of the revascularization and bone regeneration, in contrast, was observed in goats receiving the artificial bone grafts, a tendency that was far more obvious in the goats with tissue-engineered bone grafts. CONCLUSION: Tissue-engineered bone graft is eligible in repairing large defect in the caprine tibia, and radionuclide bone imaging may accurately monitor the revascularization and bone regeneration after the bone graft implantation.

Animals↗

PubMed2002

[Biocompatibility of adult human osteoblasts with coral-derived hydroxyapatite in vitro].

OBJECTIVE: To study the biocompatibility of the osteoblasts from adult human bone marrow with coral-derived hydroxyapatite (CHA) in in vitro culture. METHODS: Bone marrow was obtained from healthy adult subjects and cultured in Dulbecco's modified Eagle's medium (DMEM) containing 10 % fetal bovine serum. The subsequent cell passaging was conducted in conditioned medium containing dexamethasone, beta-sodium glycerophosphate and ascorbic acid, with the osteoblasts in culture then divided into CHA group (in which the cells were cultured with CHA) and osteoblasts group (without CHA). The proliferation and differentiation of all the cultured cells were observed at different time points under inverted phase contrast microscope, optical microscope with HE staining and scanning electron microscope respectively. Proliferation of the cultured cells were evaluated by MTT assay, and the activity of alkaline phosphatase and total micro-protein contents in these cultured osteoblasts were quantitatively detected. RESULTS: The osteoblasts from adult human bone marrow grow well in vitro, regardless of the presence of CHA, with biological and morphological characteristics similar to those of normal osteoblasts. CHA improved the adhesion, growth and proliferation of the cultured cells, showing no adverse effects on the cell functions. CONCLUSION: CHA is an optimal scaffold material for bone tissue engineering, which may potentially find clinical application for bone defect repair.

Adult↗

PubMed2002

[Improvement upon construction of tissue-engineered allogeneic cartilage molded with polyglycolic acid as the scaffold].

OBJECTIVE: To improve the method for constructing allogeneic molded cartilage by means of tissue engineering techniques. METHODS: The chondrocytes from the rib and articular cartilage of infant rabbits were harvested by type II collagenase digestion, followed by in vitro cell culture for 3 to 4 passages. The chondrocytes were then prepared into cell suspension and seeded onto C -and O -shaped pre-molded polyglycolic acid (PGA) scaffolds form chondrocyte-PGA composites, which were subsequently cultured in vitro for 7 to 10 d before implanted subcutaneously into adult rabbits. Improvement was made upon conventional shaping and implantation procedures. Morphological observation and cartilage regeneration assessment were conducted at different time points following the implantation, in comparison with the observation by conventional shaping and implantation methods. RESULTS: During in vitro cell culture, the rate of viable chondrocytes in the final cell suspension was (92+/-2)% after well-controlled prolongation of digestion trypsin, similar to the viable cell rate (93+/-2) % by traditional procedures (P>0.05). Gross observation found milk-white, newly generated cartilage which had good flexibility 4 weeks after implantation, and after 8 weeks and later, the cartilage took on the color of porcelain-white. Histological examination showed a few inflammatory cells around the newly generated immature cartilage 4 weeks after implantation, and the inflammation abated when the newly generated cartilage acquired similar histological properties to that of the original cartilage 8 weeks postoperatively and later. After 16 weeks, no blood vessel or capillaries were visible within the new cartilage. CONCLUSION: The chondrocyte viability is not affected when the cells are treated with well-controlled prolonged digestion with trypsin during in vitro cell culture. Improved PGA scaffolds shaping and the implantation procedure facilitate the regeneration of the cartilage after the implantation of the composites.

Animals↗

PubMed2002

[An experimental study of treatment of comminuted distal femur fracture with locked double- plating].

OBJECTIVE: To explore new techniques for the treatment of comminuted distal femoral fractures to promote functional restoration and reduce the complications of the fracture. METHODS: Sixteen adult canines were selected for this study, and the experimental and control hindlimb for each canine were randomly determined. Distal comminuted fracture (AO/ASIF Type C2) was induced in both sides of the canine's femurs, and one side was fixed with the double plates (steel plate and polyethylene plate), whereas the other with a single steel plate. By the end of 3, 6, 9 and 12 weeks respectively after surgery, 4 of the dogs were used for weight-bearing observation and radiological and histological examination of the limbs. RESULTS: In comparison with dogs in single plate group, double plate fixation resulted in earlier recovery of weight bearing, more abundant and better callus, finer callus moulding and quicker healing. There were slightly more inflammatory cells, however, in the tissues under the polyethylene than those under the steel plate. CONCLUSION: Locked double-plate internal fixation is an excellent alternative for treating comminuted fractures of the distal femur, and may have its potential use in clinical settings.

Animals↗

PubMed2001

Dynamic changes of TNF-alpha content in dogs after gunshot wound in the limbs in hot and humid environment.

OBJECTIVE: To investigate the dynamic changes of TNF-alpha content in the plasma and body tissues of dogs after gunshot wound in the limbs in hot and humid environment. METHODS: Eighteen dogs with gunshot wound were divided into 3 groups (6 in each), one observed in normal environment (Ne group) and the other two in hot and humid environment including a heat-acclimatized group (HA group) and a non-acclimatied group (NHA group). The contents of tumor necrosis factor-alpha (TNF-alpha) in the plasma and muscle tissues from the gunshot wound tract were measured at 0, 1, 3, 4, 6, 8, 10, 14, 18, 24 h respectively after the injury. RESULTS: TNF-alpha content in the muscular tissue from gunshot wound tract was significantly higher than that in the plasma (P<0.05). At 4 h after injury, TNF-alpha content started to rise in NE group, reaching the peak level at 14 h, the rise and peaking of which occurred at 3 and 10 h respectively in NHE group with higher peak level than that in NE group (P<0.05). The changes of TNF-alpha participates in the pathophysiological process after gunshot wound in hot and humid environment and may play the role of and indicator for the pathological changes that take place after the injury.

Journal Article↗