BACKGROUND: As a metal internal fixation material, magnesium alloy has more unique advantages, such as biodegradability and elastic modulus. The elastic modulus of magnesium alloy is similar to the compact bone,which is enough to avoid stress-shelter effect. However, biological activity represents bonding ability with the bone in the body for fracture fixation materials, which is of great significance for studies on new kinds of magnesium alloys.OBJECTIVE: To observe the microstructure of Mg-Zn-Gd alloys and to analyze the corrosion products on the material surface after immersed in simulation body fluid.METHODS: The Mg-Zn-Gd alloys were manufactured by the method of fusion casting. Scanning electron microscope with spectrometer was applied to observe microstructure and distribution of precipitated phase and corrosion products of Mg-Zn-Gd alloys in simulated body fluid.RESULTS AND CONCLUSION: The Mg-Zn-Gd alloy was composed of α-Mg solid solution containing Gd and Zn elements and eutectic structure. The eutectic structure was almost feathery, oval-shaped, herringbone-shaped and strip-shaped along the grain boundary. The main ingredients of eutectic structure included Mg, Zn and Gd elements.Deposition layer was composed of O, Mg, Ca and P elements on the surface of Mg-Zn-Gd alloy after 72 hours soak in Hank's solution. X-ray diffraction analysis showed that film layer contained Mg(OH)2 phase, which promoted calcium salt deposition and reduced the corrosion rate. So Mg-Zn-Gd alloy can obtain better biological activity.

ObjectiveTo report the results of preventive control program of severe thalassemias in Zhuhai City of Guangdong Province from 1998 to 2010.MethodsAs the guide centre of marriage and childbearing and the greatest maternity hospital in Zhuhai City of Guangdong Province,Zhuhai Municipal Maternity and Child Healthcare Hospital constructed the genetic screening network for thalassemias testing and referred for follow-up and for genetic counseling.The couples for premarital medical examination or regular healthcare examination in pregnancy were enrolled to this preventive control program.A conventional strategy of screening for heterozygote was used to identify the α- and β-thalassemia traits in women and their spouses according to the standard procedures of hematological phenotype analysis which was recommended by Thalassemia International Federation (T IF).Then those suspected couples at risk were diagnosed for α- and β-thalassemia by PCR-based DNA assays.The couples at risk for severe thalassemias were counseled and offered prenatal diagnosis and termination of pregnancy in case of an affected fetus in the rights of consent and of option voluntarily.ResultsFrom January 1998 to December 2010,85 522 brides and grooms-to-be for premarital screening and 41 503 pregnant women in addition to 14 141 partners for prenatal screening were recorded,the covering rates of premarital screening and prenatal screening in the city were 92.698％ (from 1998 to 2003) and 27.667％ (from 2004 to 2010),respectively.Totally 10 726 cases were found to be the carriers of thalassemias,with 7393 for o-thalassemia (5.237％,7 393/141 166) and 3333 for β-thalassemia (2.361％,3 333/141 166).A total of 257 couples at-risk for severe thalassemias were detected including 190 for α-thalassemia and 67 for β-thalassemia.Among them,251 (97.7％,251/257) couples were performed prenatal diagnosis.During the preventive control program,a total of 72 fetuses with severe thalassemias including hemoglobin H disease were voluntarily terminated.In Zhuhai City,the average annual birth rate of fetuses with severe thalassemia was declined by 32.9％ (49/149).ConclusionsThis study has reduced effectively birth rate of perinatal infants with severe thalassemias in Zhuhai City by genetic screening and prenatal diagnosis of thalassemia in the large population of 13 years.Our summary comes out of technical proposals for prenatal screening and diagnosis,which could be take example by preventative control of thalassemia in other regions of China where are prevalent.

Multiple sclerosis (MS) is a disease characterized as inflammatory demyelinating of the central nervous system,which is the main cause of non-traumatic neurological disability in young and middle-age adults.The main manifestations of MS are memory and information processing speed,executive function and other cognitive impairments.MS associated with memory impairment (MSMI) is often overlooked because of the occult onset,which seriously affecting patients' life quality.In recent years,with the rapid development of neuro-functional imaging,MRI has become an important method to observe and diagnose MS,providing imaging evidence for diagnosis of MSMI.The clinical and MRI research progresses of MEMI were reviewed in this article.

Objective To investigate the clinical efficacy of tibiocalcaneal arthrodesis using bone transport technique in the treatment of traumatic talus infection or loss. Methods A retrospective case series study was conducted to analyze the clinical data of 15 patients with talus infection or loss admitted to the provincial hospital affiliated to Shandong University from June 2011 to October 2017. There were 13 males and two females, aged from 19 to 47 years, with an average age of 27 years. Thirteen patients had talus infection and two patients had talus loss. All patients underwent tibiocalcaneal fusion with external fixator using bone transport technique, including four patients treated with annular external fixator and 11 with unilateral external fixator. Six patients with severe infection underwent debridement at stage I and osteotomy at stage II, and the other nine underwent debridement and osteotomy at the same time. The length of new bone, the fixation time of external fixator and complications were recorded. The American Orthopedic Foot and Ankle Society ( AOFAS ) score was used to evaluate the efficacy. Results All patients were followed up for 18-35 months, with an average of 26 months. The length of new bone in proximal tibial osteotomy area was 5-16 cm, with an average of 9 cm. The external fixators were removed after bone healing at docking site and maturation of new bone. The fixation time of external fixator ranged from 13 to 27 months, with an average of 18 months. No complications such as needle breakage, recurrence of infection and calcaneal varus occurred, and the length of both lower limbs was equal. AOFAS score was increased from preoperative (42. 0 ± 3. 6)points (31-55 points) to (76. 0 ± 4. 2)points (69-86 points ) at the last follow-up. Conclusion Tibiocalcaneal arthrodesis using bone transport technique is proved to be effective in treating traumatic talus infection or loss, which can repair the bone defect after debridement, improve the ankle-hindfoot function and improve the quality of life.

Although the first-line treatment regimens represented by R-CHOP have shown good efficacy in B-cell lymphoma, there are still some patients with recurrence and progression. With the advent of the era of tumor immunotherapy, the immunotherapy of B-cell lymphoma has been rapidly developed, including immune checkpoint inhibitors, CAR-cell, tumor microenvironment regulation, etc. This article reviews the current status of immunotherapy of B-cell lymphoma.

Objective To compare the short-term clinical efficacies of Da Vinci robotic surgical systemassisted and laparoscopy-assisted radical gastrectomy for locally advanced gastric cancer (GC).Methods The retrospective cohort study was conducted.The clinicopathological data of 162 patients who underwent minimally invasive radical gastrectomy for locally advanced GC in the First Affiliated Hospital of Army Medical University between September 2016 and September 2017 were collected.Of 162 patients,65 undergoing Da Vinci robotic surgical system-assisted radical gastrectomy were allocated into the robotic group and 97 undergoing laparoscopyassisted radical gastrectomy were allocated into the laparoscopic group.According to Japanese gastric cancer treatment guidelines,patients with upper GC and with middle or lower GC underwent respectively total gastrectomy + D2 lymph node dissection and distal subtotal gastrectomy + D2 lymph node dissection,and then Billroth Ⅱ or Roux-en-Y digestive tract reconstruction.Observation indicators:(1) surgical and postoperative situations;(2) detection of lymph node;(3) follow-up and survival situations.Measurement data with normal distribution were represented as x±s,and comparisons between groups were analyzed using the t test.Comparisons of count data were done using the chi-square test.Ordinal data were analyzed by the nonparametric test.Results (1) Surgical and postoperative situations:all 162 patients underwent successful surgery,without conversion to laparoscopic or open surgery,and pathological resection margins were confirmed as R0.Volume of intraoperative blood loss,levels of amylase in peritoneal drainage fluid at day 1,2 and 3 postoperatively,levels of serum amylase fluid at day 1,2 and 3 postoperatively were respectively (123±39) mL,(557± 181) U/L,(357± 127) U/L,(183±86) U/L,(181±47)U/L,(123±29)U/L,(85±22)U/L in the robotic group and (142±40)mL,(793±284)U/L,(497±199)U/L,(279±157) U/L,(218±45) U/L,(162±37) U/L,(120±31) U/L in the laparoscopic group,with statistically significant differences between groups (t =-3.015,-2.817,-2.364,-2.132,-2.372,-3.338,-3.720,P＜0.05).Cases with distal subtotal gastrectomy + D2 lymph node dissection and with total gastrectomy + D2 lymph node dissection,cases with Billroth Ⅱ and Roux-en-Y of digestive tract reconstruction,time of distal subtotal gastrectomy + D2 lymph node dissection,time of total gastrectomy + D2 lymph node dissection,cases with anastomotic leakage,pulmonary infection,wound infection or liquefaction and delayed gastric emptying,cases in grading Ⅱ,Ⅲ,Ⅳ and Ⅴ of postoperative complications,time of postoperative drainage-tube removal and duration of postoperative hospital stay were respectively 47,18,40,25,(222±37) minutes,(274±43) minutes,1,1,1,1,2,1,0,0,(6.5-± 1.5) days,(10.0±4.0) days in the robotic group and 74,23,69,28,(213±40) minutes,(262±39)minutes,2,4,1,0,4,1,0,1,(6.9±1.7)days,(10.0±5.0)days in the laparoscopic group,with no statistically significant difference between groups (x2=0.326,1.628,t =1.272,0.960,x2=2.501,Z=-1.342,t=-1.142,-0.115,P＞0.05).One and 1 patients in the robotic and laparoscopic groups who were complicated with esophagus-jejunum anastomotic leakage after total gastrectomy + Roux-en-Y anastomosis were cured by nutrition support therapy using feeding tube placement under gastroscopy,and 1 patient in the laparoscopic group who were complicated with gastrojejunal anastomosis leakage after distal subtotal gastrectomy +Billroth Ⅱ anastomosis received the second surgical exploration and jejunal feeding tube placement.Patients with pulmonary infection,wound infection or liquefaction and delayed gastric emptying were cured by conservative treatment.Levels of amylase in peritoneal drainage fluid and serum amylase fluid at day 1,2 and 3 postoperatively were not higher than 3 times of upper limit of normal,without treatment interventions.(2) Detection of lymph node:overall number of lymph nodes detected in the robotic and laparoscopic groups were respectively 36.82±13.41 and 35.21 ± 11.52,with no statistically significant difference between groups (t =0.786,P＞ 0.05).Results of further analysis showed that numbers of lymph node dissected in the 2nd station and upper region of pancreas in patients undergoing distal subtotal gastrectomy + D2 lymph node dissection were respectively 6.04±3.98,13.51±6.53 in the robotic group and 4.45±3.12,11.40±5.30 in the laparoscopic group,with statistically significant differences between groups (t=2.461,1.986,P＜0.05).Numbers of lymph node dissected in No 7 and 8 groups and upper region of pancreas in patients undergoing total gastrectomy + D2 lymph node dissection were respectively 5.44±2.63,2.92±1.87,10.81±4.78 in the robotic group and 3.11±1.82,1.62±1.33,7.76±3.34 in the laparoscopic group,with statistically significant differences between groups (t =3.340,2.689,2.522,P＜0.05).(3) Follow-up and survival situations:of 162 patients,148 were followed up for 2-14 months,with a median time of 8 months.During the follow-up,patients in the 2 groups had tumor-free survival.Conclusions Da Vinci robotic surgical system-assisted radical gastrectomy is safe and feasible.Compared with laparoscopy-assisted radical gastrectomy for locally advanced GC,it has advantages of clear vision of the local anatomy,less intraoperative bleeding,more numbers of lymph nodes dissected in the upper region of pancreas and lighter pancreatic injure,meanwhile,it has also certain operating advantages around the great vessels and in the deep and narrow spaces.

Objective:To study the effect of MYD88 L265P mutation on the expression of PD-L1 in tumor cells and tumor microenvironment in diffuse large B-cell lymphoma (DLBCL), and to provide theoretical basis for immunotherapy for patients.Methods:Multiplex ligation-dependent probe amplification (MLPA) was used to detect the frequency of MYD88 L265P mutation in 72 cases of DLBCL diagnosed by pathologists in Cancer Hospital of Chinese Academy of Medical Sciences from August 2008 to May 2010. Expression of PD-L1 in tumor cells and tumor microenvironment in all samples was evaluated using PD-L1 (22C3) and PD-L1 (SP142) with Ventana automatic immunohistochemical (IHC) platform. The relationship between MYD88 L265P mutation and the expression of PD-L1 in DLBCL tumor cells and tumor microenvironment was assessed.Results:Of the 72 cases of DLBCL, MYD88 L265P mutation was detected in 15 (20.8%) cases. Nine cases with JAK2 amplification were excluded, and the remaining 63 cases of DLBCL were divided into MYD88 L265P mutant group ( n=14) and MYD88 L265P wild-type group ( n=49). IHC results showed that among the 14 cases of MYD88 L265P mutant groups, PD-L1 (22C3) was positive in 7 cases (7/14) of tumor cells and PD-L1 (SP142) was positive in 4 cases (4/14) of tumor microenvironment. Among the 49 cases of MYD88 L265P wild-type group, 9 cases (18.4%) were positive for PD-L1 (22C3) in tumor cells, and 38 cases (77.6%) were positive for PD-L1(SP142) in tumor microenvironment. In addition, among the 16 cases with PD-L1(22C3) expression in tumor cells, only 2 of the 7 cases with MYD88 L265P mutation were positive for PD-L1 (SP142) in tumor microenvironment. All 9 cases with wild-type MYD88 L265P were positive for PD-L1 (SP142) in tumor microenvironment. Statistical analysis showed that the expression level of PD-L1 (22C3) in tumor cells in the MYD88 L265P mutant group was significantly higher than that in the MYD88 L265P wild-type group ( P=0.017). The expression level of PD-L1 (SP142) in tumor microenvironment in the MYD88 L265P mutant group was significantly lower than that in the MYD88 L265P wild-type group ( P=0.001). Conclusions:MYD88 L265P mutation may play an important role in the regulation of PD-L1 expression in DLBCL tumor cells and tumor microenvironment. Further studies will provide a theoretical basis for immunotherapy of DLBCL patients with MYD88 L265P mutation.

Klebsiella pneumoniae(K.pneumoniae)is an important pathogen that can cause severe hospital-and community-acquired infections.To systematically investigate its methylation features,we determined the whole-genome sequences of 14 K.pneumoniae strains covering varying serotypes,multilocus sequence types,clonal groups,viscosity/virulence,and drug resistance.Their methy-lomes were further characterized using Pacific Biosciences single-molecule real-time and bisulfite technologies.We identified 15 methylation motifs[13 N6-methyladenine(6mA)and two 5-methylcytosine(5mC)motifs],among which eight were novel.Their corresponding DNA methyl-transferases were also validated.Additionally,we analyzed the genomic distribution of GATC and CCWGG methylation motifs shared by all strains,and identified differential distribution pat-terns of some hemi-/un-methylated GATC motifs,which tend to be located within intergenic regions(IGRs).Specifically,we characterized the in vivo methylation kinetics at single-base resolu-tion on a genome-wide scale by simulating the dynamic processes of replication-mediated passive demethylation and MTase-catalyzed re-methylation.The slow methylation of the GATC motifs in the replication origin(oriC)regions and IGRs implicates the epigenetic regulation of replication initiation and transcription.Our findings illustrate the first comprehensive dynamic methylome map of K.pneumoniae at single-base resolution,and provide a useful reference to better understand epigenetic regulation in this and other bacterial species.

BACKGROUNDPelvic fractures are uncommon in elderly patients and so are infrequently addressed in the literature. The purpose of this study was to investigate the management and outcome of pelvic fractures in elderly patients.

METHODSWe retrospectively reviewed the records of pelvic fractures in elderly patients (age ≥55 years) who were treated in our department from September 1997 to May 2010.

RESULTSA total of 40 elderly patients with pelvic fractures were identified. Their mean age was 65.8 years (range 55-87 years). About 68% (n = 27) were men. The average Injury Severity Score (ISS) was 17.8 (range 6-45). Twelve (30%) patients required blood transfusion (mean 10 units) during the first 24 hours. The fractures were most frequently due to falling from a standing position (48%). Almost half (48%) were grade I breaks. Associated injuries were present in 70% (n = 28) of patients, and 65% (n = 26) had medical co-morbidities. Altogether, 29 patients (73%) underwent non-surgical management of their pelvic fracture. The average hospital stay was 25 days. There were five in-hospital deaths and one death 10 months after discharge. High ISSs (>25) were associated with increased in-hospital mortality (P = 0.018). At the final assessment (mean follow-up 15 months), 52% of the surviving patients had experienced decreased self-sufficiency.

CONCLUSIONSPelvic fractures in elderly patients result in high morbidity and mortality rates. A high ISS (>25) can be used to identify a patient at high risk. We recommend aggressive resuscitation and intensive care for that patient. For patients with an unstable pelvic or displaced acetabular fracture (≥2 mm) who can endure surgery, open reduction and internal fixation can provide adequate fixation for early weight-bearing and restoration of the bone stock.

Aged ; Aged, 80 and over ; Blood Transfusion ; Female ; Fracture Fixation, Internal ; Fractures, Bone ; etiology ; surgery ; therapy ; Hospital Mortality ; Humans ; Male ; Middle Aged ; Pelvic Bones ; injuries ; Retrospective Studies