This paper analyzed the current scientific research situation of medical postgraduates in Xi'an Jiaotong university,stated briefly the existing main problems and relevant influence factors including poor scientific research ability due to low quality enrollment,unreasonable construction of experimental platform,patchy quality of tutor teams et al.To solve the problems above,several policies were proposed,mainly including strengthening basic experimental skills of medical undergraduates,reforming the postgraduate curriculum system,optimizing the building of experimental platform and reinforcing the development of tutor teams.

OBJECTIVE To investigate the clinical and pathological characteristics and its diagnosis and treatment of the parotid gland tumor in children.METHODS The clinical data of 77 children with parotid gland tumor treated in Department of Head and Neck,Tianjin Cancer Hospital affiliated Tianjin Medical University from Dec.1985 to Dec.2007 were retrospectively studied.RESULTS Among the 77 cases,51 cases were benign tumor(66.2%),26 cases were malignant tumor(33.8%).Among the benign cases,hemangioma and lymphangioma were the most common diseases,which accounted for 37.3%(19/51).Mucoepidermoid carcinoma(34.6%, 9/26) was the most common malignancy.Sixty seven cases were treated surgically.Among 18 cases of the epithelial malignant tumors,7 cases treated combined with postoperative radiotherapy.During the period of following-up from 1 to 17 years,1 case of pleomorphic adenoma,1 case of malignant myoepithelioma and 1 case of mucoepidermoid carcinoma recurred. CONCLUSION The clinical and pathological features of parotid gland tumors in children were different from those in adults.The hemangioma,lymphangioma and teratoma are rare in adults but common in children.Half of the solid tumors of parotid gland in children are malignant,but only 23.7%in adults. The primary radical operation has great value to the prognosis of children parotid tumor.Although postoperative radiotherapy can reduce the risk of recurrence,oncogenesis in thyroid gland and the adverse effect on the orofacial development of radiotherapy in children need investigated clinically in future.

The effect of the opiate receptor antagonist naloxone on myocardial contractility and relaxation after acute coronary occlusion in rabbits and the relationship between its effect and ?-adrenergie receptor were observed. The results showed that during the early stage of acute coronary occlusion myocardial contractility and relaxation were significantly increased and cardiac function was improved by naloxone; The action of naloxone can be abolised by ?-adrenergic receptor blocker propranolol. These results indicated that there was a close correlation between the action of naloxone on myocardial contractility and relaxation and the adrenergic nerve activity.

Objective To observe the effect of IMRT combined with astragalus polysaccharide (ASP) injection on cervicocerebral tumor,radiation side effects and its influence on immune function. Methods 61 head and neck tumor patients were randomly divided into two groups.One groups received the IMRT combined with Astragalus Polysaccharide (ASP) injection (n=30) while the other group only received the IMRT(n=31). The recent effect, immune function and the side effects of radiotherapy between the 2 groups were observed and compared , changes of T-lymphocyte subsets, natural killer (NK) cell activity and the dermatitis,oral mucosa reaction,thirsty condition on patients in intraoperative or postoperative period were also observed and compared. Results The total effective rate in experimental group and the control group were 83.0% and 80.6% respectively.The cell viability of peripheral blood lymphocyte and NK cell as well as the T3、T4、NK cell value increased in IMRT-ASP group (P<0.05) after treatment. While T3、T4、NK cell value in peripheral blood decreased (P<0.05). Mucosa,dermatitis and salivary gland damage showed in IMRT-ASP group were significantly better than in control group after 3 weeks treatment (P<0.05). Conclusion ASP can improve immune function effect in head and neck tumor patients during RT, and can also eliminate the side effects of radiotherapy.

Objective:To investigate the changes of ultrastructure of myocardial cells and the expression levels of tumor necrosis factor α(TNF-α) in myocardium tissue of the diabetic rabbits during early myocardial ischemia and their mechanisms,and to provide the theoretical basis for studying the pathogenesis of diabetic myocardial ischemia injury.Methods:A total of 42 healthy male New Zealand white rabbits were chosen.The method of intravenous injection of alloxan in ear vein was used to establish the diabetic models in 26 rabbits among 42 rabbits;the method of partial ligation of left anterior descending coronary artery by thoracotomy was used to establish the diabetic myocardial ischemia models in 22 model rabbits with diabetes.A total of 16 (modeling succesfully) were divided into diabetic myocardial ischemia 7 d group and 28 d group;other 16 rabbits were used as sham operation groups at the relevant time points(7 and 28 d),and there were 8 rabbits in each group.The ultrastructure of myocardial cells was observed by transmission electron microscope;the apoptosis index (AI) of myocardial cells in ischemic myocardium tissue of the rabbits was detected by TUNEL method;the expression levels of TNF-α in ischemic myocardium tissue of the rabbits were detected by real-time RT-PCR method.Results:In sham operation groups,the nuclei of myocardial cells was bigger,the nuclear chromatin was in uniform distribution,the myofibril ordered arrangement,the sarcomere was neat;the mitochondria between myofibril were rich,and their structures were clear.For the rabbits in diabetic myocardial ischemia group,their early-stage cardiocyte nuclei were irregular in shape,myofibrils was loose in structure,the part of myofibril was broken,and the mitochondrial hyperplasia between the myocardial cells was obvious.Compared with sham operation groups,the AI of myocardial cells and the expression levels of TNF-α in the ischemic myocardial cells of the rabbits in diabetic myocardial ischemia 7 d and 28 d groups were significantly increased(P<0.05),and the indexes mentioned above in diabetic myocardial ischemia 7 d group was higher than those in diabetic myocardial ischemia 28 d group(P<0.05).Conclusion:The destruction of ultrasturctue and obvious apoptosis of the myocardial cells of the rabbits occur in the early stage of diabetic myocardial ischemia.The increasing of expression level of TNF-α may involve in the myocardial ischemic injury.

ABSTRACT:Objective To investigate the bone marrow stem cell mobilization and homing changes of peripheral blood due to diabetic myocardial ischemia in rats and the change of expression of the vascular endothelial growth factor (VEGF)and the tumor necrosis factorα(TNFα)in ischemic myocardial tissue.Methods The diabetic model of male Sprague-Dawley rats was created by intraperitoneal injection of streptozotocin first.Then the diabetic myocardial ischemia model was established through ligation of the left anterior descending coronary artery. The rats were divided into ischemic day-1,day-3,day-7,and day-28 groups.And their time-matching diabetic sham operation control group and normal sham operation control group were also established,with 6 rats in each group. Flow cytometry was used to measure the percentage of CD34+ cells in peripheral blood mononuclear cells for each group.Immunohistochemistry was used to observe the homing of CD34+ cells and the expression of VEGF and TNFαin the ischemic myocardium.Results The mobilization of bone marrow stem cells was initiated after the surgery in the rat models of myocardial ischemia in diabetes and it peaked within 1 week and decreased with the passage of time.Accordingly the homing of CD34+ cells and the expressions of VEGF and TNFαin the ischemic myocardium were significantly increased.Conclusion During the early stage,the diabetic ischemic myocardium can mobilize bone marrow stem cells into the peripheral blood and start homing to the ischemic myocardium by increasing VEGF and TNFαin the ischemic myocardium,thereby initiating the self-protection mechanisms.

Objective To explore the difference of immunosuppresive effect between the expanded Stro-1+ and Stro-1-subgroups of human mesenchymal stem cells in vitro. Methods Mononuclear cells (MNCs) were isolated from bone marrow (BM) samples and seeded in a T-75 cm2 tissue culture flask contained with Dexter medium. When 50% confluence was obtained, adherent cells were collected and incubated with anti-stro-1 antibody, and the Stro-1+ and Stro-1-MSCs were further seeded for expansion. The total culture time (median) was 15 days. Cells were then analyzed by flow cytometry. One-way mix lymphocyte reaction (MLR) (1?105 responding cells and an equal number of stimulating cells/well were co-cultured in 96-well plates) and nonspecific mitogenic stimuli phytohemagglutinin (PHA) plus interleukin-2 (IL-2) induced lymphocytes proliferation (PBL 1?105/well were mixed with PHA 10?g/ml and IL-2 500U/ml in 96-well culture plates) were established in vitro. 1?103-3?104 irradiated Stro-1+ MSCs and Stro-1-MSCs were added into the two systems at the beginning of reaction. Immunosuppressive actions of both Stro-1+ or Stro-1-MSCs were compared. Results Adherent cells contained a median of 9% (range 5%-26%) Stro-1+ cells, which expressed higher immunophenotype of MSCs. In both reaction systems, suppressive actions occurred in a dose-dependent fashion when whatever Stro-1+ MSC or Stro-1-MSC were added. However, that the addition of 1?103 Stro-1-cells enhanced rather than inhibited the lymphocyte proliferation in one-way MLR. In the presence of various concentrations of MSCs, Stro-1+ MSCs always showed a significantly increased inhibitory effects in comparison to Stro-1-MSCs (P

35), while the expression level of TGF-?1 in Stro-1-MSC was significant higher than that detected in Stro-1+MSC (2-??Ct=0.39, P

Objective To establish and stabilize a new HLA-B locus typing strategy, reference strand mediated conformation analysis(RSCA)system and to conform its advantages.Methods Of 27 hematopoitic stem cell transplant patients and 63 potential donors DNA samples were extracted from peripheral blood cells and HLA-B loci were both typed by RSCA and PCR-SSP methods. The (ambi)-(guous) results were identified by using DNA sequencing. Results Among 90 samples, 87/90 ((96.7) %) cases could be designated definitely, but one of them was disagreement with the SSP result which was confirmed by sequencing, and 67/90 ((74.4) %) cases could be typed to allelic level. 1/90 ((1.1) %) case could not be identified by RSCA for its bad PCR results. Only one allele of each 2 samples could be designated and the other could not be identified by RSCA, which were further confirmed by sequencing method, and the results confessed which were known as alleles, but there were no corresponding data in RSCA database. Twenty samples were randomly selected to identify the replication rate of RSCA, and the results demonstrated that the replication rate was 100 %. Among PCR-SSP typing results, about 10 % samples might be typed for 1-3 times to confirm their types. Conclusion RSCA had some advantages such as high resolution, high sensitivity, high accuracy, high replication, finding new alleles, large scale and low cost, and was especially suitable for unrelated donor-recipient (screening).

AIM: To select proper hydrolysis time to determine Ginkgo biloba flavonoids content. METHODS: Sample dissolved in 25mL MeOH-25%∶HCl(4∶1) mixture and was heated to hydrolyze for various time, then diluted. Flavonoids'content was determined by HPLC. The conditions were developed by Shimpack CLC-ODS(150mm?6mm) column using 0.4% phosphoric acid solution-Methanol(50∶50), the detective wavelength was at 360nm with quercetin、kaempferol and isorhamnetin as standards, temperature being 30℃. RESULTS: Contents of flavonoids of Ginkgo biloba leaves,Ginkgo biloba crude extracts and Ginkgo biloba refined extracts were highest in the hydrolysis time of 2.0h. Ginkgo biloba flavonoids can be completely hydrolyzed in 2.0h. CONCLUSION: The hydrolysis time of 2.0h is best.