Currently, hip replacement is an effective treatment for some hip joint diseases. The friction and wear of a prothesis in the human body are the main causes for the failure of joint arthroplasty. It is, therefore, very important to simulate the working conditions of a hip prosthesis in order to get an optimal design and successful clinical applications. This article summarizes wear testing methods of hip prostheses and the developing status of their simulators. Three key aspects of the simulators, i.e., the structures, motions and lubrications, are analyzed in detail. At the end, the developing trend of the simulators are discussed.
Biomechanical Phenomena ; Equipment Failure Analysis ; instrumentation ; Friction ; Hip Prosthesis ; Lubrication ; Materials Testing ; instrumentation ; Prosthesis Design

OBJECTIVETo explore clinical effects of manipulative reduction with minimally invasive percutaneous plate osteosynthesis in treating distal tibiofibular fractures.

METHODSFrom 2009 to 2011, 60 patients with distal tibiofibular fractures were treated by manipulative reduction with minimally invasive percutaneous plate osteosynthesis. Among them, there were 32 males and 28 females aged from 14 to 70 years old with an average of 41.22 +/- 2.06. According to AO classification of fractures,5 cases were type A1, 22 cases were type A2,21 cases were type A3 and 12 cases were type C1. Operation time, blood loss,time of callus and fracture healing were observed, Mazur scoring of ankle joint were used to evaluate therapeutic.

RESULTSFifty-eight incisions were healed at stage I ,and 2 cases were infected at distal tibial. Operation time was with an average of (62.34 +/- 5.66) min ranged 45 to 90 min;blood loss was 30 to 150 ml with an average of (80.57 +/- 5.59) ml;formation of callus appeared from 4 to 12 weeks,with an average of (8.24 +/- 2.06) weeks, and fracture healing time was from 3 to 6 months, with an average of (4.50 +/- 1.13) months. According to Mazur scoring of ankle joint 40 cases got excellent results, 18 good, and 2 fair.

CONCLUSIONManipulative reduction with minimally invasive percutaneous plate osteosynthesis can obtain reliable fixation. It is a good choice of treating distal tibiofibular fractures by protecting blood supply of fractures.

Adolescent ; Adult ; Aged ; Bone Plates ; Female ; Fracture Fixation, Internal ; instrumentation ; Humans ; Male ; Middle Aged ; Minimally Invasive Surgical Procedures ; Tibial Fractures ; surgery ; Treatment Outcome ; Young Adult

Objective:To investigate the subtype distribution of HIV-1 strains prevalent in four areas of China,and to study the characteristics of gag gene variation and changes in antigen epitopes under the host immune pressures. Methods:The plasma of HIV-1 infected people from Henan, Guangdong, Sichuan and Beijing in China were collected. Virion RNA was extracted directly from plasma after the virion was condensed. The gag gene was amplified by RT-PCR and nested-PCR.Sequences were subtyped by Genotyping Tool software, and phylogenetic analysis of gag gene were performed using the MEGA 4.1 software.The gene distances intra each subtype were calculated by Distance program. The Ks/Ka ratios were calculated using SNAP program. The variation analysis of CTL antigen epitopes restricted by main HLA-Ⅰ specificities in China was performed.Results:Six subtypes or circulating recombinant forms(CRFs)of HIV-1,including B',CRF07_BC,CRF01_AE,B,CRF08_BC and CRF02_AG,were identified in four areas of China.The gene distances intra each subtype were CRF01_AE>B>CRF08_BC> CRF07_BC>B' listed in order of size, meanwhile the order of Ks/Ka ratios was CRF01_AE>B>CRF08_BC>B'>CRF07_BC. Far more diversity of antigen epitopes in P17 region was observed than that in P24.Epitope mutations intra subtypes were CRF01_AE>B>B'>CRF07_BC listed in order of size. Conclusion:Itseems that CRF01_AE is under the strongest immune pressures,and displays the most diversity of gene and variation of epitopes intra subtypes prevalent in China, followed by subtype B, B' and CRF07_BC. The discrepancy of epitope mutations intra the subtypes is significant.

Objective To investigate the change of the basic fibroblast growth factor(bFGF) leve in human detrusor muscle(DM)in bladder outlet obstruction(BOO)due to benign prostatic hyperplasia(BPH)and its implication.Methods Fifty-four patients with BPH were divided into two groups:the obstructive DM stability and instability groups;and 15 men with bladder tumor who underwent operation in the same period were enrolled in the control group.The bFGF mRNA level in DM was measured by reverse transcription and polymerase chain reaction(RT-PCR)and the bFGF protein level was measured by immunohistochemical staining method.Results The bFGF-mRNA expression level of bladder smooth muscle cells was significantly lower in the control group than that in the obstructive DM stability and instability groups(all P＜0.05),but there was no significant difference between the obstructive DM stability and instability groups(P＞0.05). Conclusions The expression level of bFGF mRNA in bladder DM is elevated in BOO due to BPH,but there is little or no correlation between the increased expression of bFGF mRNA and detrusor muscle instability.

OBJECTIVETo assess the advantage and disadvantage of laparoscopic abdomino-perineal resection and open abdominoperineal resection for low rectal cancer.

METHODSPatients with low rectal cancer, collected from July 2003 to April 2006, were randomly divided into laparoscopic abdominoperineal resection group (37 cases) and open abdominoperineal resection group (37 cases). Operation time, number of lymph node removed, intra-operative blood loss, time to pass flatus, time to ambulate, time to discharge, complications, early recurrence, and economical cost were compared between the 2 groups.

RESULTSAll patients were performed successfully. For the first 10 patients, operation time of laparoscopic group was significantly longer than that of open group, but there was no significant difference between the 2 groups. Intra-operative blood loss of laparoscopic group was significantly less than that of open group, but it was reverse for the first 10 patients. There was no significant difference in time to pass flatus between the 2 groups. Time to ambulate in laparoscopic group was significantly earlier than that in open group. There was no significant difference in time to discharge between the 2 groups, but it was earlier for perineum closure in laparoscopic group. Relative complications of laparoscopic group, including pulmonary infection, abdominal wound infection or split, were significantly less than those of open group. There was no significant difference in number of lymph nodes removed, early recurrence between the 2 groups. Operation cost of laparoscopic group was significantly higher than that of open group, but there was no significant difference.

CONCLUSIONAdvantages of laparoscopic abdominoperineal resection were characterized for not only minimal invasion and good cosmetic outcome but also less blood loss, complications, and earlier postoperative recovery. The operation time, total costs and oncological clearance of laparoscopic abdominoperineal resection patients were comparable with those of open procedure patients.

Abdomen ; surgery ; Aged ; Female ; Humans ; Laparoscopy ; Male ; Middle Aged ; Perineum ; surgery ; Rectal Neoplasms ; pathology ; surgery ; Rectum ; pathology ; surgery ; Treatment Outcome

OBJECTIVETo study the antitumour effects of sodium valproate (VPA) on the proliferation, differentiation and cell cycle of Molt-4 cell and to investigate its demethylation mechanisms.

METHODSAfter Molt-4 cells trated with VPA at different concentrations, cell viability and growth curve were assessed by MTT assay. Cell cycle changes were analyzed by flow cytometry. The expression level of p15, DNA methyltransferase 1 (DNMT-1), DNMT3A and 3B mRNA were detected by RT-PCR and the methylation level was detected by hn-MSPCR.

RESULTSVPA significantly inhibited the proliferation of Molt-4 cells. After 48 h culture with 5.0 mmol/L VPA, the percentages of Molt-4 cells in G(0)/G(1) phase was (66.87 ± 3.31)% and in S phase was (8.47 ± 2.56)%, while in control group, the cells in G(0)/G(1) phase increased and in S phase decreased significantly. The p15 gene in Molt-4 cells failed to express due to its hypermethylation. The expression level of p15 gene mRNA increased significantly after exposure to VPA for 48 h. As compared with control group, the expression of DNMT-1 was down-regulated in a dose-dependent manner. The expression level of DNMT3B decreased at 10.0 mmol/L concentration.

CONCLUSIONVPA has a demethylation effect on p15 INK4B gene by inhibiting the DNMT-1 and DNMT3B gene activities to recover p15 gene activity, which arrests Molt-4 cell in G(0)/G(1) phase.

Cell Cycle ; drug effects ; Cell Line, Tumor ; DNA Methylation ; drug effects ; RNA, Messenger ; genetics ; Valproic Acid ; pharmacology

OBJECTIVEImpulse oscillometry (IOS) is a new method for determination of breathing mechanics, which features convenient operation, good repeatability and wider range analysis. As there is no standardized normal value in China at present, this study will provide a normal value of lung function determination by impulse oscillometry for children in Chengdu area.

METHODTotally 549 children were chosen at random from Chengdu area, with 292 boys and 257 girls who were 4 to 14 years old. The subjects were assigned into 10 age groups according to their chronological age with one year difference between every two adjacent groups. The respiratory total impedance (Zrs), viscosity resistance (Rrs) and elastic resistance (Xrs) at various oscillation frequency were measured by the Master Screen IOS which was manufactured by German Jaeger Company. The measured data were treated with the linear stepwise multiple regression, and established the prediction equation. At the same time, paired comparison was carried out with the measured data and equation obtained from this study, Lechtenboerger equation and prediction equation obtained from Guangzhou area.

RESULTThe total impedance and airway resistance were negatively correlated with the children's height and age. Zrs (male) = -0.756 + 189.586/height, r = -0.782, P < 0.001; Zrs (female) = -0.497 + 152.468/height, r = -0.726, P < 0.001. Rrs became the same in trend; while Xrs were proportional to the height, e.g. the values increased as the height increased. The difference of the airway resistance (R(5)-R(20)) was negatively correlated with the children's height: R(5)-R(20) (male) = 0.601 - 0.0034 x height, r = -0.677, P < 0.001; R(5)-R(20) (female) = 0.549 - 0.0031 x height, r = -0.658, P < 0.001. Among the relationships with many impulse oscillometry parameters, height ranked at first place; age at second. The multiple regression equation of IOS primary index was established. Both the measured data and the correlation coefficient of the study obtained equation were greater than the coefficient correlation of the Lechtenboerger equation, but had no significant difference compared with that of prediction equation in Guangzhou area.

CONCLUSIONThe normal value in impulse oscillometry in children in Chengdu area is different from the predicted parameters in other countries. The equation obtained from this study seems to be more suitable for the children in its local area. It is recommended to apply the predicted value from the corresponding population in the determination of the lung function by impulse oscillometry.

Airway Resistance ; physiology ; Child ; China ; Electric Impedance ; Female ; Humans ; Male ; Oscillometry ; methods ; Respiratory Function Tests ; methods ; Respiratory Physiological Phenomena

OBJECTIVETo explore the relationship between the expression of Survivin and Ki67 with prognosis of pancreatic endocrine tumors (PETs).

METHODSImmunohistochemistry for Survivin and Ki67 was performed in 25 cases of normal pancreatic tissues and 81 cases of PETs by tissue microarrays and to observe the expression and evaluate the relationship with prognosis.

RESULTS(1)The expression of Survivin and Ki67 in PETs was significantly higher than that in normal pancreatic tissues (P <0.01); (2)The expression of Survivin and Ki67 in PETs was correlated with tissue grading and the TNM-staging (P < 0.05), but not related with tumor size, location and functional status. In addition, the expression of nuclear Survivin was association with lymph node metastasis (P < 0.05). (3)The high expression of Ki67 was related with the expression of nuclear Survivin, but not related with the expression of cytoplasmic Survivin.

CONCLUSIONSurvivin and Ki67 were both expressed in PETs, which were closely related to the clinical pathological characteristics. They could be used as new indicators in the evaluation of prognosis of PETs. The expression of Survivin in nucleus had more diagnostic significance than that in cytoplasm, and that could be highly correlated with lymph node metastasis, which would be used as a new marker of poor prognosis.

Biomarkers, Tumor ; metabolism ; Cell Nucleus ; metabolism ; Cytoplasm ; metabolism ; Humans ; Immunohistochemistry ; Inhibitor of Apoptosis Proteins ; metabolism ; Ki-67 Antigen ; metabolism ; Lymphatic Metastasis ; Neoplasm Staging ; Pancreatic Neoplasms ; diagnosis ; Prognosis

BACKGROUNDVirus with nucleoside reverse transcriptase inhibitors (NRTIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs) resistant mutations show different evolution tendencies when the anti-viral therapies are interrupted. Understanding the replication fitness of drug-resistant virus is important for the study of the prevalence of drug-resistance. For this purpose, we characterized the replication capacity of HIV-1 virus carrying lamivudine (3TC) or nevirapine (NVP) resistant mutations.

METHODS3TC and NVP resistant variants were induced in vitro by selecting wild type virus in the presence of drugs. For the competitive replication assay, drug-resistant variants were cocultured with wild-type virus in the presence or absence of drugs. The ratios of the viral species were determined over time by using a real-time RT-PCR-based assay.

RESULTS3TC-resistant (M184I mutation) and NVP-resistant (Y181I mutation) virus should be selected in vitro in two different ways. The competitive replication assay showed that the ratio of virus carrying a M184I mutation increased from 98.8%, while the wild type virus decreased to 1.2% after 4 passages in the presence of 3TC; the percentage of virus carrying the Y181I mutation increased to 90.5%, while wild type virus decreased to 9.5% in the presence of NVP. In the absence of drugs, the ratio of virus carrying the M184I mutation decreased to 5.3%, while wild type virus increased to 94.7%; the ratio of virus carrying Y181I increased to 75%, while wild type virus decreased to 25% after 4 passages.

CONCLUSIONSThe NVP-resistant virus is fitter than wild type virus even in the absence of NVP that may be the reason that NNRTIs-resistant virus is spreading quickly.

Cell Line ; Drug Resistance, Viral ; genetics ; HIV-1 ; drug effects ; genetics ; growth & development ; physiology ; Humans ; Lamivudine ; pharmacology ; Mutation ; Nevirapine ; pharmacology ; Reverse Transcriptase Inhibitors ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Virus Replication ; genetics ; physiology

OBJECTIVETo study the correlation between expression of urokinase-type plasminogen activator (uPA) and capability of tumor cell seeding to the peritoneal membrane by different gastric cancer lines.

METHODSExpression of uPA in 4 human gastric cancer cell lines was examined by semi-quantitative RT-PCR, ELISA and Western blot. uPA activity was determined by an assay kit. After ip inoculation of cancer cells to nude mice, tumors on peritoneal membrane was grossly examined for tumor cell seedings.

RESULTSSGC7901 was the highest in uPA expression among human gastric cancer cell lines AGS, SGC7901, MKN45, and MKN28. MKN45 had the strongest uPA activity, while AGS was lowest in both uPA expression and activity. Peritoneal seeding tumors of various sizes were observed in mice inoculated with SGC7901 and MKN45 cells. In addition to peritoneal seedings, bloody ascites was present in mice inoculated with MKN28. The MKN45-inoculated mice took the least time to develop tumors and had the shortest surviving period. No peritoneal seeding was seen in mice inoculated with AGS cells.

CONCLUSIONThree of 4 human gastric cancer cell lines studied express uPA mRNA and activity, which correlate with their peritoneal seeding potentials.

Adenocarcinoma ; enzymology ; secondary ; Animals ; Cell Line, Tumor ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Seeding ; Peritoneal Neoplasms ; secondary ; RNA, Messenger ; biosynthesis ; genetics ; Stomach Neoplasms ; enzymology ; pathology ; Urokinase-Type Plasminogen Activator ; biosynthesis ; genetics