Effect of ultrasound microbubble carrying herpes simplex virus thymidine kinase on hepatocellular carcinoma in mice / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To observe the effect of ultrasound microbubble carrying herpes simplex virus thymidine kinase hepatocellular carcinoma in mice.</p><p><b>METHODS</b>Kunming mice were inoculated subcutaneously with H22 tumor cells. 40 male mice bearing subcutaneous hepatoma were randomized into 4 groups: PBS (group A), HSV1-TK (group B), HSV1-TK (group C), and microbubble carrying HSV1-TK (group D) were injected into the tail vein every 3 days. Mice in group C and D were exposed to ultrasound. The expression of TK protein was detected by western blot. Ganciclovir (GCV) was intraperitoneally injected at a dose of 100 mg x kg (-1) x d(-1) in group B, group C and group D. The tumor size was measured every 2 days.</p><p><b>RESULTS</b>TK gene could be injected precisely into hepatocellular carcinoma with ultrasound monitor, and the expression of TK protein was found in all 4 groups. Expression in group D was higher than others (P < 0.05). The rate of tumor growth inhibition were 0 in group A, 3.90%+/-1.80% in group B, 22.70%+/-2.86% in group C, 41.25%+/-3.20% in group D (group B vs group C, P < 0.05; group D vs group C, P < 0.05; group D vs group B, P < 0.05).</p><p><b>CONCLUSION</b>Ultrasound microbubble not only improve target gene therapy, but also enhance transfection efficiency.</p>

Effects of HBsAg pulsed dendritic vaccination on anti-HBs production in immunosuppressed rats after liver transplantation / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the effects of HBsAg pulsed dendritic vaccination on anti-HBs production in immunosuppressed rats after liver transplantation (LT).</p><p><b>METHODS</b>Brown-Norway liver allografts were transplanted into Lewis recipients. The transplanted Lewis rats were injected with EK506 (2 mg/kg) and randomly divided into two groups: rats in HBsAg-DCs group (n = 15) were intraperitoneally injected with HBsAg pulsed DCs at 14 d and 28 d after LT, and rats in the HBsAg group (n = 15) were injected with HBsAg (200 mul) once a week for 12 weeks. Rats without any immunosuppressive treatment after LT served as controls (n = 5). IL-2 and IFN-gamma mRNA expression in spleen were analyzed by RT-PCR, serum IL-2, IFN-gamma and anti-HBs were detected by ELISA.</p><p><b>RESULTS</b>High dose of FK506 resulted in the immunosuppressed in LT rats, as evident by low production of IL-2 and IFN-gamma, and without liver rejection compared to rats in the control group. HBsAg-DCs induced high titer of anti-HBs antibody, however, titer of anti-HBs were seldom detectable in the HBsAg group at 1, 2 and 3 mouth after vaccination.</p><p><b>CONCLUSION</b>The capacity of HBsAg-DCs to induce anti-HBs in immunosuppressed rats suggested that DC vaccine may prevent HBV recurrence in liver transplanted patients.</p>

Retrospective analysis of 3,958 patients with facial injuries / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine the causes and incidence of facial injuries by an epidemiologic retrospective study.</p><p><b>METHODS</b>A total of 3 958 patients with facial injuries treated at Department of Oral and Maxillofacial Surgery, West China School of Stomatology, Sichuan University from 1955 to 2001 were investigated. Data regarding age, gender, cause of injury, pattern of fracture and associated systemic injuries were reviewed.</p><p><b>RESULTS</b>The male to female ratio of the patients with facial injury was 4.27:1 and 33.4% of patients were aged between 21 and 30 years. The most common cause of injury was traffic accident (30.6%), followed by falls (21.4%) and collision (15.8%). A total of 794 patients (20.1%) showed only soft tissue injuries. 1 100 patients (27.8%) had multiple fractures in facial bones and 2,064 patients (52.1%) had single fracture. The mandibular fracture was most frequently seen, followed by the maxilla and the zygoma. The most common site of mandible fracture was the body (31.2%), followed by the symphysis (22.7%), the condylar (20.5%) and the angle (13.7%). Accompanied injuries to brain and skull happened in 916 patients (23.1%).</p><p><b>CONCLUSIONS</b>Bone fractures were more common in hospitalized patients with facial injuries. The numbers and sites of fracture were related to the causes of injuries and anatomic structure of the bone. The brain and skull injuries, the most often and seriously accompanied injuries, would not be neglected.</p>

A study on repairing mandibular defect by means of tissue-engineering and human bone morphogenetic protein-2 gene transfection in osteoporotic rats / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of repairing bone defect with methods of tissue-engineering and human bone morphogenetic protein-2 (hBMP-2) gene transfection in osteoporotic rats.</p><p><b>METHODS</b>Twenty-four 6-month-old female Sprague-Dawley rats underwent ovariectomy, while 8 rats received sham-operations. Three months later, bone mesenchymal stem cells (BMSC) harvested from osteoporotic rats were divided into two groups randomly. Experimental group were transfected by recombinant plasmid carrying hBMP-2 gene, and control group left untreated. All BMSC were seeded into coralhydroxyapatite scaffolds. Then the cell/scaffold constructs were implanted into the defect site created in the ramus of mandible of osteoporotic rats respectively.</p><p><b>RESULTS</b>Positive results were confirmed by immunohistochemistry and in situ hybridization in experimental group. New bone formation was found at the margin of the defect treated with the BMSC modified by hBMP-2 gene transfer at 4 weeks after implantation and appeared mature 8 weeks after the treatment. However, the amount of newly formed bone was much less and there was some adipose tissue at defect margins 8 weeks after implantation in control group.</p><p><b>CONCLUSIONS</b>The results of this experiment indicate that BMSC-mediated rhBMP-2 gene therapy in conjunction with bone tissue engineering may allow for successful treatment of large bone defects in osteoporosis rats.</p>

Expression of human interleukin-1 receptor antagonist in the transfected chondrocytes of temporomandibular joint / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression of the human interleukin-1 receptor antagonist (hIL-1ra) in the transfected chondrocytes of temporomandibular joint (TMJ).</p><p><b>METHODS</b>Chondrocytes of TMJ in vitro were transfected by hIL-1ra gene via cationic liposome as a medium. The stable transfected cells were selected by G418. The proliferations of the transduced cell were examined with the growth curve, cell population doubling time. The protein expressing in different periods was detected by immunocytochemistry and enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The proliferation suppression of gene transfected cells fell significantly with compared to normal cells. The expression of hIL-1ra was detected in the cell plasma and the cell culture supernatant. The highest expression of IL-1ra protein was at the time of 48 hours after gene transfection. The transiently transfected cells were secreted IL-1ra protein continuously 28 days and the stably transduced cells were secreted IL-1ra protein till 72 days.</p><p><b>CONCLUSION</b>This study showed that hIL-1ra protein expressed positively in the cell plasma and the culture supernatant after gene transfection within a certain periods.</p>

Expression changes of interleukin-1 receptor associated kinase-4 during endotoxin tolerance development in kupffer cells / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the mechanism of endotoxin tolerance (ET) through observing the expression of interleukin 1 receptor associated kinase-4 (IRAK-4) during endotoxin tolerance development in Kupffer cells (KCs).</p><p><b>METHODS</b>Isolated KCs of Balb/c mouse were divided into two groups: the non-endotoxin tolerance (NET) group and the endotoxin tolerance (ET) group, which were pretreated with 10 ng/ml lipopolysaccharide (LPS) for 24 h. Then, the two groups were treated with 100 ng/ml LPS. The expressions of IRAK-4 gene and protein level were determined by RT-PCR and Western blot. The activities of NF-kappaB of KCs and the TNFalpha level were estimated by ELISA at 0 h, 1 h, 3 h, 6 h and 12 h after LPS stimulation.</p><p><b>RESULTS</b>The ultimate level of IRAK-4, the activities of NF-kappaB and the TNFalpha level were evidently lower in the ET group than those in the NET group (t = 12.4, 17.4 and 138.9 respectively, P<0.01).</p><p><b>CONCLUSIONS</b>Pretreatment with LPS on KCs could induce endotoxin tolerance of KCs and inhibition of IRAK-4 expression may be one of the reasons for its development.</p>

The effect of glycine on CD14 and NF-kappa B in Kupffer cells from rat liver grafts after ischemia-reperfusion injury / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the effect of glycine on CD14 and NF-kappa B in Kupffer cells from rat liver grafts after ischemia-reperfusion injury (IRI).</p><p><b>METHODS</b>The rats were randomly divided into an IRI group, saline solution preconditioning group, and glycine preconditioning group. Their survival rates, graft functions, and hepatic histopathologic examinations were observed after IRI. Kupffer cells (KCs) following IRI were isolated and cultured to detect CD14 mRNA, NF-kappa B binding activity, and the TNF alpha and IL-1 level in the supernatant of the media.</p><p><b>RESULTS</b>(1) Glycine preconditioning greatly enhanced the one-week survival rate (chi2 = 6.67 and 8.57 respectively), improved graft function, and ameliorated the histopathologic signs of injury. (2) The CD14 mRNA expression level (F = 7.64), NF-kappa B binding activity (F = 11.47), TNF alpha and IL-1 production (F = 14.08 and 9.56 respectively) in the glycine group were significantly lower than those in the other two groups.</p><p><b>CONCLUSION</b>Glycine could efficiently protect rat liver grafts from ischemia-reperfusion injury by repressing the expression of CD14 and NF-kappa B binding activity in Kupffer cells and inhibiting the productions of TNF alpha and IL-1.</p>

A study on the chondrogenesis of the compound of alginate gelatin and bone marrow stromal cells in vivo / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the chondrogenisis by alginate gelatin and rats' bone marrow stromal cells (BMSCs) chondrogenicly induced in vitro.</p><p><b>METHODS</b>Thirty-two male adult SD rats were assigned randomly to experimental and control groups. In experimental group, bone marrow was obtained from the right tibias of all the rats. After expanding and culturing 3 passages, induced BMSCs by chondrogenic culture medium for 10 days. Suspended induced cells in alginate gelatin, and injected the complex into the hypodermic tissue of the backs of rats autogenously. In control group only alginate gelatins were injected. The grafts were taken out for examinations 4 and 8 weeks after the operations.</p><p><b>RESULTS</b>Considerable cartilage appeared in experimental group 8 weeks after operations. Regular HE staining and alcian blue staining showed a great deal of cartilage holding chondrocyte masses surrounded by abundant matrix. Alginate gelatin decompounded obviously, and the rest distributed among newly formed cartilage. No cartilage appeared in control group all through.</p><p><b>CONCLUSION</b>BMSCs and alginate gelatin have a beautiful future in cartilage tissue engineering.</p>

The study of cell biocompatibility of new pattern biphasic calcium phosphate nanocomposite in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the cell biocompatibility of porous biphasic calcium phosphate nanocomposite in vitro.</p><p><b>METHODS</b>Bone marrow mesenchymal cell (BMSCs) obtained from SD rat bone marrow were in vitro induced and proliferated. Afler their osteoblast phenotypes were verified, BMSCs were seeded onto prepared porous biphasic calcium phosphate nanocomposite (Experiment group) and common porous hydroxyapatite (Control group). The cell adhesion was evaluated by scanning electron microscope. Synthesis of alkaline phosphatase enzyme (ALP) and osteocalcin were detected and cell cycle was detected by flow cytometry.</p><p><b>RESULTS</b>BMSCs could fully attach to and extend on the material in experiment and control group, Moreover, experiment group were superior to control group in adhesion, proliferative abilities and osteogenic activity.</p><p><b>CONCLUSION</b>BMSCs can differentiate to osteoblast phenotype; the porous biphasic calcium phosphate nanocomposite as bone tissue engineering scaffold has good cell biocompatibility.</p>

Cultivation and induced differentiation of bone marrow stromal cells of SD rats with type I osteoporosis in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the biological features and osteoblast/adipocyte phenotypes of bone marrow stromal cells (BMSCs) of Sprague-Dawley (SD) rats with Type I osteoporosis by induced culture.</p><p><b>METHODS</b>Six-month-old SD rats were used in this study. 16 female rats were randomly divided into two groups. Eight rats were ovariectomied as experimental group to establish the modle of Type I osteoporosis, while other rats received sham-operation. Three month later BMSCs of 16 rats were isolated by discontinueous gradient centrifugation and then plated in alpha-MEM medium as primary culture. Secondary harvested cells were cultured for 14 days in alpha-MEM medium supplemented with dexamethasone, ascorbic acid, vitamin D3, beta-glycerophosphate or dexamethasone, 3-isobutyl-1-methylxanthine, insuline, and indomethine. The cells were screened by inverted microscope each day and cell growth was studied with cell counting. The osteoblast and adipocyte phenotypes were verified by cytochemistry staining, counted the percentage of positive stained cells.</p><p><b>RESULTS</b>The weight and bone mineral density of rats were statistically different between experimental group and control group. Gomori and Von Kossa's staining demonstrated positive osteoblast phenotypes of alkaline phosphatase and mineralized nods by osteogenic inducer, while Oil Red O staining identified BMSCs treated with adipogenic medium resulted in adipocyte formation and there was no significant difference in the percentage of positive stained cells between two groups.</p><p><b>CONCLUSION</b>The model of Type I osteoporosis has been established successfully. BMSCs from SD rats with osteoporosis maintain their differentiation potential.</p>

Study on multi-lineage potential of bone marrow mesenchymal stem cells derived from green fluorescent protein transgenic mice / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the multi-lineage potential of bone marrow mesenchymal stem cells (MSCs) derived from transgenic mice with green fluorescent protein (GFP) gene in vitro.</p><p><b>METHODS</b>A 6-week-old GFP transgenic mouse was executed by dislocation of cervical vertebra, and the marrow in tibia and thighbone was washed out with asepsis. The limited cell strains of MSCs derived from GFP transgenic mice (GFP-MSCs) were obtained with density gradient centrifugation. The passage 3 GFP-MSCs were induced to differentiate into osteoblast, adippcyte, neuron with solution of calcium induction medium, adipogenic medium and neural induction medium respectively. After being calcium-induced, the activity of alkaline phosphatase on GFP-MSCs was determined by micro-plate reader, and alizarin red staining was performed to test the formation of calcium concentration. The adipo-induced MSCs were detected with oil red O staining. Immunocytochemical staining was performed to detect the expression of NSE on neuron-induced MSCs.</p><p><b>RESULTS</b>The ALP activity of GFP-MSCs heightened gradually along with being calcium-induced, and alizarin red staining showed positive. Oil red O staining of adipo-induced cells and NSE immunocytochemical staining of neuron-induced cells demonstrated positive.</p><p><b>CONCLUSION</b>The limited cell strain of GFP-MSCs possesses multi-lineage potential, which can be used as an efficient tracking facility for studying the mechanism of multi-lineage potential on the MSCs.</p>

Expression and secretion of human tumor necrosis factor gene transfected on human embryo myoblasts / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe human tumor necrosis factor-alpha (hTNF-alpha) expression and secreting level of human embryo myoblasts transfected by hTNF-alpha gene.</p><p><b>METHODS</b>Human embryo myoblasts were transfected with shuttle plasmid pSV23SHTNF containing hTNF-alpha gene by cationic liposomes DOSPER. The control group was only given equivalent liposomes except plasmid. After culturing for 24, 48, 72 and 96 hours, hTNF-alpha expression level of human embryo myoblasts was observed with immunocytochemistry staining, and hTNF-alpha secreting of human embryo myoblasts was analyzed by ELISA.</p><p><b>RESULTS</b>After transfected by hTNF-alpha gene for 24, 48, 72 and 96 hours, the human embryo myoblasts displayed significant secretion of hTNF-alpha in the cultural supernatant (P < 0.05), and overexpression in cytoplasma and cell membrane.</p><p><b>CONCLUSION</b>Transfection of hTNF-alpha gene to human myoblasts made myoblasts secrete high concentration of hTNF-alpha, implying it is feasible that transfecting muscle cells surrounding tongue carcinoma lesion with hTNF-alpha gene can prevent tongue carcinoma from intruding into deeper muscle tissue.</p>

Study on mRNA expression of fibronectin and integrin beta1 during fracture healing / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the spatial and temporal expression changes of fibronectin and integrin beta1 mRNA during fracture healing.</p><p><b>METHODS</b>Using in situ RT-PCR technique, the spatial and temporal expression pattern of both fibronectin and integrin beta1 mRNA was detected on paraffined slices in different rabbit mandibular fracture healing phases.</p><p><b>RESULTS</b>(1) The mRNA of integrin beta1 and fibronectin was widely expressed in fractured bone cells. The positive stain existed in cytoplasm and nucleolus. (2) After 7 days of fracture, increaseded integrin beta1 mRNA expression was observed, and it reached maximal levels approximately 14- 30 days post-fracture and returned to normal levels after 60 - 90 days. (3) Fibronectin mRNA was detected on 3 days post-fracture, it reached maximal levels at 7 - 14 days, faint expression was detected at 30 days, undetectable 60 days afterwards.</p><p><b>CONCLUSION</b>During fracture healing, the mRNA expression of integrin beta1 and fibronectin increased locally, FN and Itg beta1 cooperate with each other, it is suggested that they have an important influence on fracture healing.</p>

An experimental study of the inhibitory effects on the activation of endotoxin-induced Kupffer cells through short hairpin RNA targeting interleukin-1 receptor associated kinase-4 gene / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the inhibitory effects on the activation of endotoxin-induced Kupffer cells (KCs) through short hairpin RNA (shRNA) targeting interleukin-1 receptor associated kinase-4 (IRAK-4) gene.</p><p><b>METHODS</b>Two effective transfection shRNA plasmid (pSIIRAK-4-A, pSIIRAK-4-B) and one invalidated plasmids (pSIIRAK-4-C) targeting IRAK-4 gene were constructed. The isolated mouse KCs were divided into three groups: the normal control group, the RNAi control group (pSIIRAK-4-C) and the RNAi effective group (pSIIRAK-4-A, pSIIRAK-4-B). Then KCs were stimulated with 0.1 microg/ml lipopolysaccharide (LPS) after 24 h transfection with the constructed plasmid. The expression of IRAK-4 gene and protein level were determined by RT-PCR and Western blot at 6 h after LPS stimulation, and the activities of NF-kappaB in KCs and the TNFalpha level were estimated by ELISA at 0 h, 1 h, 3 h, 6 h and 12 h.</p><p><b>RESULTS</b>The level of IRAK-4, the activities of NF-kappaB and the TNF-alpha level in the RNAi effective group were evidently lower than those in normal and RNAi control groups (P < 0.01) at 1 h, 3 h, and 6 h. Especially, the pSIIRAK-4-A group in which the changes of the above indices were of no difference (P > 0.05), had better inhibited effects than that of the pSIIRAK-4-B group (P < 0.01).</p><p><b>CONCLUSION</b>The shRNA targeting IRAK-4 gene could effectively inhibit the activation of endotoxin-induced KCs.</p>

A study on myogenic differentiation of human adipose tissue-derived stromal cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To isolate human adipose tissue-derived stromal cells and study the potential of osteogenic differentiation after inductive culture.</p><p><b>METHODS</b>Liposuction human adipose tissues were minced and digested with collagenase type I. The obtained stromal cells were plated in BGJb medium as primary culture for ten days. The second passage cells were harvested and plated in DMEM/F12 medium supplemented with 10% FBS, 5% horse serum and 50 micromol/L hydrocortisone for myogenic induction culture. The cell-anchored slips were removed and fixed in 4% formaldehydam polymerisatum. Toluidine blue, Mallory's phosphotungstic hematoxylin staining and monoclonal antibody to human skeletal muscle myosin heavy chain immunocytochemical methods were used to assay the differentiation of cells.</p><p><b>RESULTS</b>It was observed that the size and shape of induced cells were much different from those of non-induced cells. Toluidine blue, Mallory's phosphotungstic hematoxylin staining demonstrated there were many basophilic striations within cytoplasm and multinucleated myotubes were formed. Immunocytochemical stain indicated that characterastic skeletal myosin heavy chain was positive in myogenic induced cells.</p><p><b>CONCLUSION</b>It seems that human adipose tissue represents an abundant reservoir of adult stem cells that have multi-germline potential to differentiate into myoblasts. Adipose tissue derived stromal cells will be another alternative source for cell-based tissue engineering in skeletal muscle reconstruction.</p>

Heterotopic chondrogenesis of human adipose tissue-derived stromal cells loading on alginate gel / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To isolate and chondro-inductive culture of human adipose tissue-derived stromal cells and to study their heterotopic chondrogenesis by loading them on alginate gel.</p><p><b>METHODS</b>Liposuction human adipose tissues were minced and digested with collagenase type I. The obtained stromal cells were primarily cultured in BGJb medium for ten days. Secondary harvested cells were cultured in DMEM-F12 medium supplemented with 10%FBS, 6.25 mg/L insulin, 10 mg/L TGF-beta1, 50 mg/L of freshly prepared L-ascorbate for 14 days. After in vitro assay of chondrogenic phenotypes, the cells at density of 10(10)/L were mixed with 1.2% alginate sodium and 102 mmol/L CaCl(2). The cross-linking cell-alginate gel were injected into four BALB/C athymic mice subcutaneously (1 ml for each mouse). Meanwhile, the auto-controls were set by injecting equal dose of simple alginate gel and pure cells in two opposite buttocks of the same mouse subcutaneously. Two mice were sacrificed at fourth and eighth week postoperatively and all samples were removed, fixed, embedded in paraffin and cut into sections of 5 micro m thick. HE staining, Alcian blue and modified Masson's trichrome staining were employed to observe chondrogenesis histologically.</p><p><b>RESULTS</b>Alcian blue and immunocytochemical staining revealed chondroitin sulfate and collagen II in cell matrix after having been chondro-inductive cultured for 14 days. At intervals of fourth and eighth week, heterotopic chondrogenesis is (cartilage formed) within cell-alginate injected sites were found in all mice but negatively in auto-controls. Histologically the hypertrophic chondrocytes were among cartilage matrix in different staining. All alginate gel and solitory cells absorbed within two to three weeks postoperatively in auto-controls.</p><p><b>CONCLUSION</b>It seems that stromal cells derived from human adipose tissue presents a potential for chondrogenic differentiation.</p>

Immunohistochemical analysis of dendritic cell in oral squamous cell carcinoma / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To elucidate the functional status of dendritic cells (DC) in the tissue of oral squamous cell carcinoma by analyzing characteristic phenotype of them.</p><p><b>METHODS</b>34 specimens from oral squamous cell carcinoma cases primarily treated with surgery were selected as test group. In addition, 30 specimens of normal mucosa from oral mucocele cases were used as control. Distribution of DC expressing CD1a+, HLA-DR+ and CD83+ in tumor tissue and normal mucous membrane was observed by immunohistochemistry. The number of DC expressing the antigens, which represented the density of DC infiltrating into tissue, was counted by microscope. The density of DC and the rate of DC expressing HLA-DR in oral carcinoma group and control were statistically compared.</p><p><b>RESULTS</b>There was no CD83+ DC in all cases, but CD1a+ DC was found in all samples. The density of CD1a+ DC in tumor tissue was significantly lower than that in normal mucous membrane (P < 0.05). HLA-DR antigen expressed on the surface of DC in tumoral epithelium of 27-case carcinoma specimens and in normal mucous epithelium of 23 cases. The rate of HLA-DR positive expression of TIDC had no statistic significance between the two groups.</p><p><b>CONCLUSION</b>The lower density of DC infiltrating in tumor tissue might reflect the microenviromental immunodeficiency of hosts with oral squamous cell carcinoma, and the functional mature of DC might be inhibited by the immunosuppressive action of oral squamous cell carcinoma.</p>

Influence of super high molecular weight poly D,L-lactic acid on viability and new bone formation of osteoblasts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the influence of the viability and new bone formation of osteoblasts by the super high molecular weight poly D,L-lactic acid (SHMW-PDLLA).</p><p><b>METHODS</b>1. The osteoblasts derived from neonatal rat were grown and maintained at steep of SHMW-PDLLA and normal culture medium. The viability and function of the osteoblasts were measured with MTT array. 2. The plate and screws made of SHMW-PDLLA were implanted and fixed at the artificial fractured mandible of dogs. Specimens were gained at 3 and 6 months and examined with macroscopy and SEM.</p><p><b>RESULTS</b>1. There is no significant difference of OD values between the experimental group and the control group (P > 0.05). The SHMW-PDLLA isn't toxic to osteoblast at 1 week and 2 weeks, and the toxicity is 3% at 3 days. 2. There were a lot of new bone formed between the implanted SHMW-PDLLA plate and bone tissues under SEM.</p><p><b>CONCLUSION</b>SHMW-PDLLA hasn't pathological influence on the viability and new bone formation of osteoblasts and it is feasible in tissue engineering of bone.</p>

The role of cyclooxygenase 2 and prostaglandin I2 in the development of portal hypertensive gastropathy / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To study the role of cyclooxygenase 2 (COX 2) and prostaglandin I2 (PGI2) in the development of portal hypertensive gastropathy (PHG).</p><p><b>METHODS</b>Forty Wistar rats were divided into surgery group (32) and control group (8). Partial portal vein ligation method was used to narrow the sectional area of portal vein to establish the experimental model of PHG in surgery group rats. Then they were divided into four groups (8 rats in each). The free pressure of portal vein was determined at the 1st, 2nd, 3rd, 4th weeks after the operation, and 8 rats were killed to observe the pathological change of gastric mucosa. The levels of 6-keto-PGF1 alpha, a stable metabolite of PGI2, were determined by radioimmunoassay in gastric mucosa homogenate and the blood of portal vein. The expression of COX 2 in gastric mucosa was determined by immunohistochemistry.</p><p><b>RESULTS</b>The free pressure of portal vein increased rapidly after partial portal vein ligation and maintained a high stable level after 1 week. They were (2.40+/-0.15) kPa, (2.38+/-0.17) kPa, (2.52+/-0.21) kPa, and (2.46+/-0.17) kPa at the 1st, 2nd, 3rd, and 4th weeks after partial portal vein ligation, while it was (0.90+/-0.16) kPa in control group (t>or=17.356, P<0.05). The gastric mucosa appeared pale, edema, hyperaemia, surface erosion, punctate hemorrhage and these lesions were more apparent with the time after the operation. The pathological examination showed that the gastric mucosa and submucosa thickened. The vessels of gastric mucosa and submucosa expanded and increased. There were lymphocytes and neutrophils infiltration around the vessels in the gastric mucosa and submucosa. The 6-keto-PGF1 alpha levels in gastric mucosa and the blood of portal vein increased rapidly and maintained a high level after partial portal vein ligation,which were higher than those in control group (104.52pg/ml+/-25.11pg/ml vs 73.62pg/ml+/- 20.33pg/ml, t=2.710, P<0.05; 180.21pg /ml+/-37.56pg /ml vs 142.11pg /ml+/-31.51pg /ml, t=2.198, P<0.05). The results of immunohistochemistry showed that the intensity and degree of the COX 2 staining in gastric tissue increased at the 1st, 2nd, 3rd, 4th weeks after partial portal vein ligation, while the COX 2 in control group rats was negative.</p><p><b>CONCLUSIONS</b>The expression of COX 2 and PGI2 in gastric tissue increased in portal hypertension. PGI2 as an inflammatory medium, damages the gastric mucosa by expanding vessels and other mechanisms in portal hypertension. It may be one of the important factors contributing to the development of PHG.</p>