BACKGROUND:Except for mechanical properties and physical and chemical properties, corrosion resistance testing is necessary for a variety of biomedical materials applied in the oral environment to ensure the biocompatibility of materials. OBJECTIVE:To explore the corrosion resistance of titanium abutment and different titanium aloysin vitro. METHODS:Corrosion environment byin vitroartificial saliva was constructed with pH=6.0 at (37±0.5)℃. Potentiodynamic polarization technique, scanning electron microscope and X-ray diffraction methods were employed to assess the corrosion resistance of titanium aloy, gold aloy, nickel-chromium aloy, and titanium abutment immersed in the artificial saliva for 24 hours. RESULTS AND CONCLUSION:Different aloys had different steady-state potentials, and the range of passivation region was the largest for gold aloy, folowed by titanium abutments and titanium aloys, and the smalest for nickel-chromium aloy. After 24 hours of immersion in the artificial saliva, passivation films appeared on the surface of different materials. under the scanning electron microscope, the nickel-chromium aloy surface showed obvious traces of corrosion and there were a large number of large-diameter deep pits, but no corrosion occurred on the surface of the remaining three kinds of aloys; on the surface of nickel-chromium aloy, the contents of chromium, molybdenum and aluminum were decreased, and the contents of nickel and oxygen were increased, but there were stil no changes on the surface of the remaining aloys. Cr2O3 was found on the surfaceof nickel-chromium aloy, TiO2 was generated on the surface of titanium abutment and titanium aloy, but Au and Pt stil existed in a single phase on the surface of gold aloy. These findings indicate that titanium aloy and titanium abutment have similar corrosion resistance that is inferior to the gold aloy, but better than the nickel-chromium aloy.

Objective To investigate the therapeutic effect of transcatheter arterial chemoembolization(TACE) combined with CT-guided percutaneous radiofrequency ablation(PRFA) in treating advanced primary hepatocellular carcinoma.Methods 40 cases with advanced primary hepatocellular carcinoma were randomly divided into TECA group(n=20) and TACE and PRFA group(n=20).Results The complete necrosis rate of tumor,the recurrence rate and one-year survival rate were 22.5%(9/40),37.5%(15/40) and 75.0%(30/40),respectively in TACE group and 90.0%(36/40),12.5%(5/40) and 90.0%(36/40),respectively in TACE and PRFA group.There were significant statistical differences between the two groups(P value were 0.002,0.002 and 0.008,respectively).Conclusion The therapeutic effects of TACE combined with CT-guided PRFA show better results than that of TACE alone.

Thirty-seven patients with primary osteosarcoma treated with local radiation and arterial perfusion of cytotoxic agents followed by systemic chemotherapy from April 1986 to April 1992. Several patients themselves stopped the treatment. All patients were divided into 3 groups: Group A (18 cases) were treated by local radiation and arterial perfusion of DDP, followed by systemic chemotherapy; Group B (14 cases) were treated by local radiation and arterial perfusion with no or insufficient dose of systemic chemotherapy; Group C (5 cases) were treated by local radiation and arterial perfusion with insufficient half dose and no systemic chemotherapy. Except the patients in group C, all other patients(32 cases) were followed-up from 24 to 95 months. Local control rate of the tumors was 93.8%, hypokinesis rate of the limps decreased from 93.8% to 40.6%, and mean survival time with no evidence of cancer was 38 months after treatment . survival rates of 2,3,5 and 7 years in group A were 94.4%,92.3%,72.7% and 50%,respectively.The mean survival time from lung metastasis to death in 19 patients was 13.6 months. Our date showed that long term survival of group A was superior to other groups (P

WRKY proteins, a big family of transcription factors, are involved in regulation diverse developmental and physiological processes in plants. Here, a novel WRKY gene, OsWRKY52, was isolated from a rice cDNA library. This gene included an open reading frame of 1 719 bp in length, and the deduced polypeptide contained 572 amino acids,sharing 54% identity with a WRKY1 protein from Avena sativa. Expression of OsWRKY52 gene was induced rapidly by Magnaporthe grisea in the incompatible interaction with rice plant. OsWRKY52 protein, expressed prokaryotically bound specifically to W box cis elements derived from the promoter of a rice PR1a. Transcriptional activation assay was performed by a yeast one- hybrid method. Regions of transactivation were identified to be the N-terminal serine- and threonine-rich islands and the C-terminal acidic domain of OsWRKY52. These results suggest that OsWRKY52, as a transcription activator, may be involved in defense responses against Magnaporthe grisea in rice plants.

Objective To evaluate the effects of different depths of sedation on serum adiponectin (ADP) concentrations in elderly patients undergoing general anesthesia.Methods A total of 120 elderly patients of both sexes,aged 65-83 yr,weighing 45-75 kg,of American Society of Anesthesiologists physical status Ⅱ or Ⅲ,undergoing elective noncardiac surgery under general anesthesia,were divided into Ⅰ and Ⅱ groups (n =60 each) using a random number table.Propofol was given by closed-loop target-controlled infusion,and bispectral index value was maintained at 40-50 in group Ⅰ and at 50-60 in group Ⅱ.The cognitive function was assessed by the Montreal Cognitive Assessment at 1 day before operation ant 1 and 7 days after operation.Blood samples were collected from the internal jugular vein immediately before surgery,at 2 h after the beginning of surgery and at 1 and 7 days after surgery for determination of serum ADP and S-100β protein concentrations.Results Compared with group Ⅰ,Montreal Cognitive Assessment scores were significantly increased at 1 and 7 days after surgery,the serum concentrations of ADP were increased and S-100β protein concentrations in serum were decreased at 1 and 7 days after surgery,and the intraoperative requirement for ephedrine and atropine and incidence of postoperative cognitive dysfunction were decreased during surgery in group Ⅱ (P＜0.05).Conclusion Maintaining BIS value at 50-60 can reduce the development of postoperative cognitive dysfunction,which is related to the increased concentration of serum ADP in elderly patients undergoing general anesthesia.

Objective: To investigate the feasibility and safety of the medial approach "four-step method" in the laparoscopic mobilization of splenic flexure. Methods: A retrospective cohort study was performed. Clinical data of 157 colorectal cancer patients undergoing the medial approach "four-step method" in the laparoscopic mobilization of splenic flexure at Gastrointestinal Surgical Department of Guangdong Provincial People′s Hospital from July 2015 to June 2018 were retrospectively analyzed. Of 157 cases, 17 were transverse colon cancer, 94 were descending colon cancer, 25 were sigmoid cancer and 21 were rectal cancer; 89 were male and 68 were female; mean age was (61.8±10.3) years and mean body mass index was (23.2±3.7) kg/m². The medial approach "four-step method" in the laparoscopic mobilization of splenic flexure was performed as follows: (1) The root vessels were treated with the "provocation" technique to expand the Toldt′s gap. This expansion was extended from the lateral side to the peritoneum reflex of left colonic sulcus, from the caudal side to the posterior rectal space, and from the cephalad side to the lower edge of pancreas. (2) The left colonic sulcus was mobilized, converging with the posterior Toldt′s gap. Mobilization was carried out from cephalad side to descending colon flexure, freeing and cutting phrenicocolic ligament and splenocolic ligament, and from caudal side to peritoneal reflex. (3) Gastrocolic ligament was moblized. Whether to enter the great curvature of stomach omentum arch when the gastrocolic ligament was cut, that was, whether to clean the fourth group of lymph nodes, should be according to the tumor site and whether serosal layer was invaded. (4) Transverse mesocolon was moblized and transected at the lower edge of the pancreatic surface, merging with the posterior Toldt′s gap, and from lateral side to lower edge of the pancreatic body, merging with the lateral left paracolonic sulcus. Safety and short-term clinical efficacy of this surgical procedure was summarized. Results: All the patients completed this procedure. During operation, 3 cases were complicated with organ injury, including 1 case of colon injury, 1 case of spleen injury and 1 case of pancreas injury. No operative death and conversion to open surgery was found. The average operation time was (147.5±35.1) minutes, the average intra-operative blood loss was (40.8±32.7) ml and the average number of harvested lymph node was (16.1±5.8), including (4.0±2.3) of positive lymph nodes. The first exhaust time after surgery was (41.3±20.6) hours, the fluid intake time was (1.5±1.3) days, the postoperative hospital stay was (5.2±2.3) days. Eight (5.1%) cases developed postoperative complications, and all were improved and discharged after conservative treatments. According to the TNM classification system, postoperative pathology revealed that 31 patients were stage I, 51 were stage II, 53 were stage III, 22 were stage IV. Conclusion The medial approach "four-step method" is safe and feasible, which can effectively decrease the operation difficulty of the laparoscopic mobilization of the splenic flexure.

Objective To investigate the feasibility and safety of the medial approach "four?step method" in the laparoscopic mobilization of splenic flexure. Methods A retrospective cohort study was performed. Clinical data of 157 colorectal cancer patients undergoing the medial approach "four?step method" in the laparoscopic mobilization of splenic flexure at Gastrointestinal Surgical Department of Guangdong Provincial People′s Hospital from July 2015 to June 2018 were retrospectively analyzed. Of 157 cases, 17 were transverse colon cancer, 94 were descending colon cancer, 25 were sigmoid cancer and 21 were rectal cancer; 89 were male and 68 were female; mean age was (61.8±10.3) years and mean body mass index was (23.2±3.7) kg/m2. The medial approach "four?step method" in the laparoscopic mobilization of splenic flexure was performed as follows: (1) The root vessels were treated with the "provocation"technique to expand the Toldt′s gap. This expansion was extended from the lateral side to the peritoneum reflex of left colonic sulcus, from the caudal side to the posterior rectal space, and from the cephalad side to the lower edge of pancreas. (2) The left colonic sulcus was mobilized, converging with the posterior Toldt′s gap. Mobilization was carried out from cephalad side to descending colon flexure, freeing and cutting phrenicocolic ligament and splenocolic ligament, and from caudal side to peritoneal reflex. (3) Gastrocolic ligament was moblized. Whether to enter the great curvature of stomach omentum arch when the gastrocolic ligament was cut, that was, whether to clean the fourth group of lymph nodes, should be according to the tumor site and whether serosal layer was invaded. (4) Transverse mesocolon was moblized and transected at the lower edge of the pancreatic surface, merging with the posterior Toldt′s gap, and from lateral side to lower edge of the pancreatic body, merging with the lateral left paracolonic sulcus. Safety and short?term clinical efficacy of this surgical procedure was summarized. Results All the patients completed this procedure. During operation, 3 cases were complicated with organ injury, including 1 case of colon injury, 1 case of spleen injury and 1 case of pancreas injury. No operative death and conversion to open surgery was found. The average operation time was (147.5±35.1) minutes, the average intra?operative blood loss was (40.8±32.7) ml and the average number of harvested lymph node was (16.1±5.8), including (4.0±2.3) of positive lymph nodes. The first exhaust time after surgery was (41.3±20.6) hours, the fluid intake time was (1.5 ± 1.3) days, the postoperative hospital stay was (5.2 ± 2.3) days. Eight (5.1%) cases developed postoperative complications, and all were improved and discharged after conservative treatments. According to the TNM classification system, postoperative pathology revealed that 31 patients were stage I, 51 were stage II, 53 were stage III, 22 were stage IV. Conclusion The medial approach "four?step method" is safe and feasible, which can effectively decrease the operation difficulty of the laparoscopic mobilization of the splenic flexure.

Objective To investigate the feasibility and safety of the medial approach "four?step method" in the laparoscopic mobilization of splenic flexure. Methods A retrospective cohort study was performed. Clinical data of 157 colorectal cancer patients undergoing the medial approach "four?step method" in the laparoscopic mobilization of splenic flexure at Gastrointestinal Surgical Department of Guangdong Provincial People′s Hospital from July 2015 to June 2018 were retrospectively analyzed. Of 157 cases, 17 were transverse colon cancer, 94 were descending colon cancer, 25 were sigmoid cancer and 21 were rectal cancer; 89 were male and 68 were female; mean age was (61.8±10.3) years and mean body mass index was (23.2±3.7) kg/m2. The medial approach "four?step method" in the laparoscopic mobilization of splenic flexure was performed as follows: (1) The root vessels were treated with the "provocation"technique to expand the Toldt′s gap. This expansion was extended from the lateral side to the peritoneum reflex of left colonic sulcus, from the caudal side to the posterior rectal space, and from the cephalad side to the lower edge of pancreas. (2) The left colonic sulcus was mobilized, converging with the posterior Toldt′s gap. Mobilization was carried out from cephalad side to descending colon flexure, freeing and cutting phrenicocolic ligament and splenocolic ligament, and from caudal side to peritoneal reflex. (3) Gastrocolic ligament was moblized. Whether to enter the great curvature of stomach omentum arch when the gastrocolic ligament was cut, that was, whether to clean the fourth group of lymph nodes, should be according to the tumor site and whether serosal layer was invaded. (4) Transverse mesocolon was moblized and transected at the lower edge of the pancreatic surface, merging with the posterior Toldt′s gap, and from lateral side to lower edge of the pancreatic body, merging with the lateral left paracolonic sulcus. Safety and short?term clinical efficacy of this surgical procedure was summarized. Results All the patients completed this procedure. During operation, 3 cases were complicated with organ injury, including 1 case of colon injury, 1 case of spleen injury and 1 case of pancreas injury. No operative death and conversion to open surgery was found. The average operation time was (147.5±35.1) minutes, the average intra?operative blood loss was (40.8±32.7) ml and the average number of harvested lymph node was (16.1±5.8), including (4.0±2.3) of positive lymph nodes. The first exhaust time after surgery was (41.3±20.6) hours, the fluid intake time was (1.5 ± 1.3) days, the postoperative hospital stay was (5.2 ± 2.3) days. Eight (5.1%) cases developed postoperative complications, and all were improved and discharged after conservative treatments. According to the TNM classification system, postoperative pathology revealed that 31 patients were stage I, 51 were stage II, 53 were stage III, 22 were stage IV. Conclusion The medial approach "four?step method" is safe and feasible, which can effectively decrease the operation difficulty of the laparoscopic mobilization of the splenic flexure.

BACKGROUNDTo study the effects of huTNF-α and hIL-2 gene transfection on the expression of MDR1 and LRP genes in lung cancer cell lines.

METHODShuTNF-α and hIL-2 gene plasmids were constructed and transfected into A549, GLC-82, H446 and H460 cells with lipofectinmin. Positive clones were screened out by G418. The expressions of MDR1 and LRP genes were detected at mRNA level by reverse transcription polymerase chain reaction (RT-PCR) in the non transfected cells and the cloned cells.

RESULTSMDR1 gene was positive in A549, GLC-82, H446 and H460 cell lines, LRP gene was positive in A549, GLC-82 and H460 cell lines; The transfected cell lines expressed both huTNF-α and hIL-2 gene, and the A549, H446 and H460 cell lines transfected with hIL-2 gene had no MDR1 expression at mRNA level compared with the non transfected ones.

CONCLUSIONSMDR1 and LRP genes are expressed in lung cancer cell lines, which indicates the presence of intrinsic drug resistance before any form of therapy. MDR1 gene is not expressed in hIL-2 transfected cell lines, which demonstrates that hIL-2 gene modulates the MDR1 gene expression at mRNA level, and may reverse the multidrug resistance of lung cancer.