BACKGROUND:Acelular matrix which is decelularized but retains the matrix components in the nature materials can reduce the immunogenicity of natural materials effectively and keep the material mechanical strength. OBJECTIVE:To prepare the natural biological scaffold material by using elution method to remove the cels in the rabbit costicartilage matrix. METHODS:After removal of the surrounding tissues, the costicartilage samples from New Zealand white rabbits were randomly divided them into three groups: costicartilages untreated as normal control group, detergent-enzyme digestion for 48 hours as 48-hour treatment group, detergent-enzyme digestion for 96 hours as 96-hour treatment group. Hematoxylin-eosin staining and electron microscope were used to observe decelularized effects. At 7 days of induction, bone marrow mesenchymal stem cels, 3×109/L, were colected and co-cultured with alogeneic acelular costicartilage matrixin vitro. At 3 and 7 days of co-culture, the composite was taken for observation of cel growth on the cel-free substrate surface under electron microscope. RESULTS AND CONCLUSION:Two or three cartilage cels were closely packed in each cartilage pit, began to depigment using the detergent-nuclease digestion method, and then completely depigmented at 96 hours after treatment. At 3 days of co-culture, there were a large amount of polygon-shaped adherent cels with pseudopodiasobserved on the acelular matrix surfacein vitro, and cels could proliferate and divide in partial regions. At 7 days of co-culture, adherent cels spread mostly throughout the acelular matrix surface, these cels were flat-shaped and extended with multiple interconnected processes. Mass of secreted excelular matrixes were deposited on the matrix surface and showed frost-like changes, indicating the prepared acelular matrix has favorable cytocompatibility.

BACKGROUND: A few mesenchymal stem cells (MSCs) can be found in peripheral blood.OBJECTIVE: To isolate rabbit peripheral blood MSCs and induce its differentiation into osteoblasts.DESIGN, TIME AND SE'I-I'ING: The cytological in vitro study was performed at the Central Laboratory of Shangdong Provincial Hospital from June to December 2008.MATERIALS: A total of 6 New Zealand rabbits were purchased from Shandong Academy of Agricultural Sciences. α-MEM and L-DiEM were bought from Hyclone.METHODS: Full-thickness skin (3 cm×3 cm) (dorsal muscular layer was left) was incised at various sites of rabbit back, every 3days. Incised skin was dressed following orthotopic transplantation. Each rabbit received four consecutive wounds. Peripheral blood was collected from femoral vein before injury and 1 week after injury. MSCs were harvested from peripheral blood by density gradient cantrifugation. MSCs were divided into 2 groups, which were respectively incubated in α-MEM supplemented with 10% fetal bovine serum and L-DiEM. Cells at passage 2 and 1 ×105/cm2 were incubated in a 12-well plate and induced with H-DiEM containing osteogenic inductor.MAIN OUTCOME MEASURES: The following parameters were measured: cell morphology before and after injury; colony forming efficiency of MSCs; outcome of osteogenic induction.RESULTS: Following primary medium change and before injury, obtained cells were normal. Twenty-four hours following incubation and after injury, MSCs were spindle or polygonal, and adhered to the wall. 5-6 days later, cell colonies appeared.Compared with the L-DiEM group, the number of primary culture colony formation in α-MEM group was significantly greater (P < 0.05). Peripheral blood MSCs were spindle, tdangle or polygonal, with the presence of processes, 2-3 nuclei and cell division phase, and slowly proliferated following osteogenic induction. At day 7 after differentiation of MSCs into osteoblasts, positive rate of alkaline phosphates was above 80%. At day 21, calcium deposition was detected by Alizarin Red S (positive staining).CONCLUSION: MSCs could be harvested from peripheral blood of wounded rabbits, with characteristics of osteogenic differentiation, α -MEM was more suitable than L-DiEM for peripheral blood MSCs to growin vitro.

OBJECTIVETo explore the prognostic significance of monosomal karyotype (MK) in patients with acute myeloid leukemia (AML).

METHODSThe clinical data of 498 AML patients were analyzed retrospectively.

RESULTSOf the 498 patients, 233 (46.8%) cases had an abnormal karyotype. 42 patients fulfilled the criteria for MK, which were 8.4% of all cases and 18.0% of patients with abnormal karyotype, respectively. The most frequent autosomal monosomies were -7 and -17. 70 patients had complex karyotype (CK), in all patients and patients with abnormal karyotype accounted for 14.1% and 30.0%, respectively. Patients with MK were associated with significantly older (median age 62.5 vs 52 years, P=0.003), and lower HGB concentrations (62.5 vs 77 g/L, P=0.009) and lower WBC counts (7.0×10⁹/L vs 11.7×10⁹/L, P=0.008). Among MK cases, the most frequent chromosome abnormalities were complex karyotype, -7, -5, 7q-, and 5q-. In univariate analysis, MK patients had worse survival than those without MK (7.3 months vs 26.3 months, P<0.001). CK patients also had poorer outcomes than patients without CK (14.8 months vs 26.3 months, P<0.001). In CK patients, survival was worse in MK patients than patients without MK (7.4 months vs 19.2 months, P=0.007). By COX analysis, MK was an independent prognostic factor, beyond NCCN criteria and CK [HR=2.610 (1.632-4.175), P<0.001].

CONCLUSIONMK was an independent adverse prognostic factor in AML patients.

Abnormal Karyotype ; Humans ; Karyotyping ; Leukemia, Myeloid, Acute ; Monosomy ; Prognosis ; Retrospective Studies

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To investigate the distribution and antimicrobial resistance profile of clinical bacteria isolated from blood culture in China.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2018 to December 2019. Antibiotic susceptibility tests were conducted with agar dilution or broth dilution methods recommended by US Clinical and Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 14 778 bacterial strains were collected from 50 hospitals, of which 4 117 (27.9%) were Gram-positive bacteria and 10 661(72.1%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.2%), Klebsiella pneumoniae (17.0%), Staphylococcus aureus (9.7%), coagulase-negative Staphylococci (8.7%), Pseudomonas aeruginosa (3.7%), Enterococcus faecium (3.4%), Acinetobacter baumannii(3.4%), Enterobacter cloacae (2.9%), Streptococci(2.8%) and Enterococcus faecalis (2.3%). The the prevalence of methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus were 27.4% (394/1 438) and 70.4% (905/1 285), respectively. No glycopeptide-resistant Staphylococcus was detected. More than 95% of S. aureus were sensitive to amikacin, rifampicin and SMZco. The resistance rate of E. faecium to vancomycin was 0.4% (2/504), and no vancomycin-resistant E. faecalis was detected. The ESBLs-producing rates in no carbapenem-resistance E. coli, carbapenem sensitive K. pneumoniae and Proteus were 50.4% (2 731/5 415), 24.6% (493/2001) and 35.2% (31/88), respectively. The prevalence of carbapenem-resistance in E. coli and K. pneumoniae were 1.5% (85/5 500), 20.6% (518/2 519), respectively. 8.3% (27/325) of carbapenem-resistance K. pneumoniae was resistant to ceftazidime/avibactam combination. The resistance rates of A. baumannii to polymyxin and tigecycline were 2.8% (14/501) and 3.4% (17/501) respectively, and that of P. aeruginosa to carbapenem were 18.9% (103/546). Conclusions:The surveillance results from 2018 to 2019 showed that the main pathogens of bloodstream infection in China were gram-negative bacteria, while E. coli was the most common pathogen, and ESBLs-producing strains were in majority; the MRSA incidence is getting lower in China; carbapenem-resistant E. coli keeps at a low level, while carbapenem-resistant K. pneumoniae is on the rise obviously.

Objective:To investigate the bacterial composition and antimicrobial resistance profile of clinical isolates from bloodstream infections in China.Methods:The clinical bacterial strains isolated from blood culture were collected during January 2020 to December 2020 in member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS). Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute(CLSI, USA). WHONET 5.6 was used to analyze data.Results:During the study period, 10 043 bacterial strains were collected from 54 hospitals, of which 2 664 (26.5%) were Gram-positive bacteria and 7 379 (73.5%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (38.6%), Klebsiella pneumoniae (18.4%), Staphylococcus aureus (9.9%), coagulase-negative Staphylococci (7.5%), Pseudomonas aeruginosa (3.9%), Enterococcus faecium (3.3%), Enterobacter cloacae (2.8%), Enterococcus faecalis (2.6%), Acinetobacter baumannii (2.4%) and Klebsiella spp (1.8%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 27.6% and 74.4%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci were detected. More than 95% of Staphylococcus aureus were sensitive to rifampicin and SMZco. No vancomycin-resistant Enterococci strains were detected. Extended spectrum β-lactamase (ESBL) producing Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 48.4%, 23.6% and 36.1%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.3% and 16.1%, respectively; 9.6% of carbapenem-resistant Klebsiella pneumoniae strains were resistant to ceftazidime/avibactam combination. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii. The prevalence rate of carbapenem-resistance of Pseudomonas aeruginosa was 23.2%. Conclusions:The surveillance results in 2020 showed that the main pathogens of bloodstream infection in China were gram-negative bacteria, while Escherichia coli was the most common pathogen, and ESBL-producing strains declined while carbapenem-resistant Klebsiella pneumoniae kept on high level. The proportion and the prevalence of carbapenem-resistant Pseudomonas aeruginosa were on the rise slowly. On the other side, the MRSA incidence got lower in China, while the overall prevalence of vancomycin-resistant Enterococci was low.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.