In this paper, we investigate the boundedness character, the global attractivity and the periodic nature of the svstem of ratiol difference equatious:xn+1=p+yn-k/xn,yn+1=q+xn-k/yn,n=0,1,2..., where p>0, q>0, k∈ of the system of rational difference equations:xn+1=P+yn-k/xn, yn=q+xn-k/yn,n=0,1,2 {1,2,…} and the initial values x1, y1∈(0,∞), i=- k, -k+1,… 0. Some new results are obtained.

Objective To study the effect of c-myc small interference RNA(siRNA) on c-mye protein in leukemic cells, and investigate a new method of gene therapy on leukemia. Methods siRNA against c-myc mRNA were designed and synthesized. The siRNA at 100 nmol/ml density was transfected into HL-60 cells. The cells cultured at 24 h, 48 h or 72 h were collected after being transfected, and the total protein of the cells was extracted according to the instruction booklet of TRIzol reagent. The expression level of c-myc protein was examined by Western blotting. Results After being treated with siRNA of c-myc, the quantity of c-myc protein was obviously reduced. It was remarkably lower than that of the control group. Furthermore after 72 h treatment with siRNA, the expression of c-myc protein reached its lowest. Conclusion The siRNA of c-myc can suppress the expression of c-myc protein in HL-60 cells. There are sequence targeted and time-dependence effect. The siRNA of c-myc may become a new tool of gene therapy on leukemia.

Objective To study the internalization mediated by heat shock protein 70 (HSP70) receptors expressed on the surface of dendritic cells (DCs). Methods DCs from C57BL/6 mouse bone marrow were divided into HSP70 receptor-blocking group, non-receptor-blocking group and control group. The HSP70-FITC positive cells were detected by flow cytometry (FCM). Results FCM indicated that in HSP70 receptor-blocking group, the HSP70 receptors could be almost totally blocked by 50?g HSP70. With the increase of HSP70-FITC dosage, the number of HSP70-FITC positive cells increased. In non-receptor-blocking group, the rates of the HSP70-FITC positive cells were up to 90% either when 50?g HSP70-FITC or 100?g HSP70-FITC was used with no remarkable difference between them. Conclusions The internalization mediated by HSP70 receptors plays a major role in the stage of ingestion of HSP70 with the characteristics of saturation and priority. Once the receptors are blocked, non-receptor pathway participates in internalization in a dose-dependent manner.

The article analyses the current situation of the unbalanced development of Chinese higher medical education and the reasons for it,and points out that to promote its development,gradation and diversify development of education must be realized.

ObjiectiveTo investigate the clinical efficacy of Chinese medicineShuxin-Huoxue decoction on coronary heart disease and angina pectoris.MethodsThis study was a randomized controlled trial. 86 patients with coronary heart disease and angina pectoris and conformed to the indusive criteria were randomly divided into a control group and a treatment group, with 43 cases in each group. The control group was treated with conventional western medicine, the treatment group was treated with traditional Chinese medicineShuxin-Huoxue decoction. Serum homocysteine (Hcy) was measured by enzymatic cycling assay, high sensitive C reactive protein (hs-CRP) was measured by immunotubidimetric assay and left ventricular ejection fraction (LVEF), stroke volume (SV), cardiac output (CO), cardiac index (CI) were measured by color doppler echocardiography before and after treatment. The clinical effect of the two groups was evaluated.ResultsThe total effective rate of the treatment group and the control group was 90.7% (39/43) and 74.4% (32/43) respectively,there was significant difference (χ2=3.957,P=0.047). Followed up for 4 weeks, LVEF(65.7% ± 8.7% vs. 61.5% ± 8.4%,t=2.277), SV(86.9 ± 16.8 ml vs.79.2 ± 16.5 ml,t=2.144), CO(49.3 ± 9.1 ml/m2 vs. 44.7 ± 8.8 ml/m2,t=2.383), CI (3.7 ± 0.9 L/min?m2 vs. 3.3 ± 0.7 L/min?m2,t=2.301) of the treatment group were significantly improved after treatment than those of the control group (P<0.05), and the decrease of serum Hcy  (8.7± 3.7mmol/L vs. 11.4± 3.5mmol/L,t=3.476), hs-CRP (2.7± 1.1 mg/L vs. 3.5± 1.3 mg/L,t=3.081) level of the treatment group were better than those of the control group(P<0.01).ConclusionTraditional Chinese medicineShuxin-Huoxue decoction has good therapeutic effect on coronary heart disease and angina pectoris.

Objective To investigate the diagnosis and treatment of bilateral thyroid carcinoma(BTC).Methods Clinical data of 68 cases with BTC from July 2001 to July 2008 were analyzed retrospectively.Results All patients underwent surgical treatment.22 cases received total thyroidectomy and bilateral functional neck dissection,30 cases received total thyroidectomy and unilateral functional neck dissection,14 cases received total thyroidectomy and lymph node dissection of Ⅵ area,2 cases received palliative resection.12 cases received proper radioactive 131I therapy after operation.Postoperative complications occured in 16 cases,including 5 cases with transient recurrent nerve paralysis,1 case with permanent injury of recurrent laryngeal nerves received trachea incision,1 case with tracheomalacia and asphyxia,6 cases with convulsion caused by hypocalcemia,1 case with permanent hypoparathyroidism,2 cases with chylous fistula(one was cured by saturing and ligaturing and the other by conservative treatment).Low echo solid or cystic solid nodules in thyroid were found by preoperative ultrasonic scan in all cases,in which 38(55.88%)cases were associated with gravel calcified lesion in thyroid nodules.The diagnosis was comfirmed by needle aspiration biopsy(NAB)in 42 cases preoperatively and 64 cases(94.12%)by frozen section intraoperatively.63(92.64%)cases were followed up postoperatively for a period from 6 months to 5 years,all 5 cases with recurrence and/or metastasis had tumor-free survival after reoperation except for 1 case with undifferentiated cancer died on the 6th month after operation.Conclusions Total thyroidectomy and lymph node dissection is essential to the treatment of BTC.Gravel calcified lesion revealed by preoperative high frequency ultrasonagraphy is an important characteristic for preoperative diagnosis of thyroid cancer.

Aim To obtain genetically engineered cytokine with potentialities of clinical application. Methods Anti-human hepatocellular carcinoma (HCC) single chain gene fragment(scFv25) was linked with human TNFα gene to form a fusion gene of anti--HCC cytokine， then it was subcloned into prokaryotic GST fusion expression vector pGEX 4T-1 and expressed in the host E.coli. Indirect immunofluorescent staining was performed on HCC cell smearing slides in order to evaluate the activity of purified aim protein, then initial tumor regression trial was carried out in nude mice bearing HCC to evaluate the targeting therapeutic value of scFv25-TNFα . Results scFv25-TNFα had similar specificity as parental antibody HAb25 for SMMC-7721 antigen. The tumor regression trial to the 2 mm HCC xenografts in nude mice showed that scFv25-TNFα had certain targeting cytotoxicity capacity and the efficiency was 3/3 with complete remission. The cytotoxicity of scFv25-TNFα was better than that of TNFα , whose efficiency was only 2/3 and no complete remission was seen. Conclusion scFv25-TNFα is the anti-HCC cytokine, which have certain potentialities of clinical application.

BACKGROUND: There has been increasing attention in the study of adolescent idiopathic scoliosis (ALS)and bone metabolism, which is accompanied by osteopenia and osteoporosis. Interleukin(IL) -6, a cytokine that strongly promotes bone resorption, participates in the regulation of bone metablism.OBJECTIVE: To explore the relationship between changes of bone mineral density(BMD) and serum IL-6 content in AIS.DESIGN: A controlled non-randomized concurrent study involving patients with AIS and and healthy volunteers.SETTING: The clinic and wards of the department of spinal surgery of a university-affiliated hospital.PARTICIPANTS: Thirty-six patients with AIS(6 males and 30 females aged 12 to 18 years) were treated in the Department of Spinal Surgery, Drum Tower Hospital, Medical College of Nanjing University from July to October 2003, who had a Cobb angle ranging from 34° - 109° and curvature of the thoracic spine. Thirty-six healthy adolescent volunteers(7 males and 29 females within the range of 13 - 18 years old) served as the control group.METHODS: The BMD was measured at L2- L4 and the proximal femur;(including the femoral neck, greater trochanter and Ward' s triangle) by dual-energy X-ray absorptiometry and serum IL-6 determined by enzyme-linked immunosorbent assay(ELISA).MAIN OUTCOME MEASURES: ① BMD of the lumbar spine and femur ② Comparison of serum IL-6 content of all the subjects.RESULTS: The BMD of AIS patients at L2- L4, femoral neck, greater trochanter and Ward' s triangle was 0.79±0. 12, 0.78±0. 12, 0.65± 0. 10, and 0. 69 ± 0. 13 g/cm2, respectively, all significantly lower than the corresponding measurements of the control group(1.09 ± 0. 11, 0.95 ± 0. 11,0. 78 ± 0. 10, and 0. 88 ± 0. 11 g/cm2, respectively, P ＜ 0. 001), whereas the serum IL-6 content in the patients was significantly higher than that in the control subjects ( P ＜ 0. 005). The changes of BMD at the lumbar spine and the three sites of femur were negatively correlated with serum IL-6 in AIS patients( P ＜ 0. 001 ), but not so in the control group( P ＞ 0.05).CONCLUSION: The BMD is decreased and serum IL-6 elevated in patients with AIS, and excessive secretion of IL-6 might be one of the important factors of osteopenia in AIS.

Objective To study the protective effects of nitroxides against hu man keratinocytes oxidative damage induced by H2O2 and its possible mechanisms. Methods Normal human keratinocyte cultures obtained from foreskin were served as test-system. Human keratinocytes were cultured in human keratinocytes growth m edia (KGM) without serum and supplemented with 0.1 mmol/L Ca2+. Experiments wer e performed in culture when the cells grew to fuse. Oxidative damage was induced by adding H2O2 directly to the culture media at different concentrations in the present and absence of nitroxides [(2, 2, 6, 6-tetramethylpiperidine (TEMPO) a nd 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine (TEMPOL)]. The cell viability w as monitored and the intracellular level of reduced glutathione (GSH), the activ ities of glutathione-peroxidase(GSH-Px), superoxide dismutase (SOD), and catal ase were evaluated. Results ①H2O2 could cause damage to human keratinocytes dir ectly. There was a significantly negative correlation between H2O2 concentration and cell viability. ②The level of GSH in keratinocytes lowered with treatment of H2O2. The activities of GSH-Px, SOD and catalase decreased. ③Pretreatment o f the cells with TEMPO and TEMPOL inhibited the damaging effects of H2O2 on cell viability and on cell antioxidant enzymatic systems. Conclusion The results of the study suggest that nitroxides may provide protection for cultured human kera tinocytes against H2O2-induced oxidative injury. It is proposed that the effec ts of nitroxides against cell oxidative damage be related to their protection of cellular enzymatic activities and maintaining cellular antioxidant systems.

Objective To study the effect of paeonol (PAE) and panax notoginseny saponins (PNS) on the expressions of collagenⅠandⅢprotein and mRNA in rats with acute myocardial infarction (AMI), and to explore the molecular mecha?nism of improving myocardial fibrosis. Methods The rat model of AMI was made using the left anterior descending coro?nary branch ligation.According to the intervention rats were divided into model group, PAE (8 mg/kg) group, PNS (40 mg/kg) group, PAE (4 mg/kg)+PNS (20 mg/kg) group, PAE (8 mg/kg)+PNS (40 mg/kg) group and captopril positive control group (10 mg/kg). Sham operation group, only wear line without ligation. The left ventricular mass index (LVMI) was detected after treatment for 28 d. Masson staining was used to observe changes of myocardial fibrosis. Western blot assay and RT-PCR technique were used to detect protein and mRNA expression levels of collagenⅠandⅢ. Results The values of LVMI were increased in model group compared with those of sham operation group and treatment groups. Compared with PAE group and PNS group, values of LVMI were significantly decreased in PAE (4 mg/kg)+PNS (20 mg/kg) group and PAE (8 mg/kg)+PNS (40 mg/kg) group. There was a more significant decrease in formula high dose group (P < 0.01). The model group showed pathological change. There were different degrees of improvement in pathological structure in all treatment groups, more sig?nificant improvement was found in formula low dose group, formula high dose group and captopril positive control group. There were different degrees of increase in expressions of collagenⅠandⅢprotein and mRNA in model group compared with those of sham operation group and treatment groups. Compared with PAE group and PNS group, the protein and mRNA expression levels of collagenⅠandⅢwere significantly decreased in formula low dose group and formula high dose group,more significant decreased was found in formula high dose group (P<0.05). Conclusion Compound of paeonol and PNS can improve myocardial fibrosis in myocardial infarction rats, which may be related with reduced expressions of collagenⅠandⅢprotein and mRNA.