BACKGROUND:Degradable polymer materials initiate the degradation process immediately after implantation. How to regulate the degradation of these materials is rarely reported at present. OBJECTIVE:To study the effect of ultrasonic wave on control ing the degradation of polymer materials. METHODS:The sample is made ofε-caprolactone/L-lactide copolymer, and its core was coated with low density polyethylene on the surface with the fol owing four different methods. (1) The core surface was firstly covered with CaCl 2 powder, and then coated with polyethylene. (2) The core was firstly coated with polyethylene and coarsened for 3 hours. (3) The core surface was firstly covered with CaCl 2 powder, and then coated with polyethylene, and coarsened for 3 hours. (4) The core was directly coated with polyethylene. The four kinds of specimens obtained were embedded in pork for ultrasonic bombardment experiment in vitro. RESULTS AND CONCLUSION:In the specimens prepared with methods 1 and 4, the lyophobic layer could protect core materials before ultrasonic treatment, and no absorption peak was found at 631 nm. After ultrasonic treatment, the lyophobic layer was destroyed, toluidine blue dye was released, leading to change the color of immersion solution and increase the absorption peak at 631 nm. In the specimens prepared with methods 2 and 3,the lyophobic layer cannot exhibit the protection effects, the absorption peak was found at 631 nm. Under electron microscope, the appearance of the specimens in four groups was changed obviously. It is feasible to control the starting of the degradation by coating the degradable copolymer with LDPE and using ultrasonic as a trigger.

Objective To investigate the current status of hand hygiene(HH) among health care workers(HCWs) in clinical laboratories in medical institutions in Xi'an City.Methods HH status of HCWs in clinical laboratories in medical institutions in Xi'an was performed random on-the-spot sampling and monitoring.Results A total of 240 HH specimens of HCWs in clinical laboratories in 80 medical institutions in Xi'an City were collected, 127 detected results were qualified, the total qualified rate was 52.92%.The qualified rates of medical institutions were as follows: municipal hospitals 62.67%,workers' hospitals 55.95%,private hospitals 40.74%;comprehensive medical institutions 67.68%,specialized medical institutions 42.55%;tertiary medical institutions 79.63%(n=43),secondary and below medical institutions 45.16%(n=84),there were significant differences in HH qualified rate among HCWs in different types of medical institutions(all P<0.01).Of different HH detection items, detection rates of Escherichia coli and Staphylococcus aureus were 0.83% and 8.33% respectively.There were significant differences in HH compliance rates among HCWs of all age groups(χ2=9.103,P<0.05), HCWs aged≥50 years had the highest qualified rate of HH(71.43%), followed by those aged<30 years (67.82%),HCWs in 40~ year age group had the lowest HH qualified rate (39.66%).Conclusion The qualified rate of HH of HCWs in clinical laboratory of medical institutions in Xi'an City is low, it is necessary to enhance the procaution awareness of HCWs in clinical laboratories, strengthen quality control of HH, strictly implement standard hand-washing procedures to reduce occurrence of HAI.

Objective:Investigating the changes of phenotype and moleculars associated with aging with the increase of passage times of human dental pulp stem cells (hDPSC), to explore the role of WW-containing transcriptional regulator 1 (WWTR1) in the aging mechanism.Methods:hDPSCs were cultured by tissue block method, and were divided into 4 groups according to the age, algebra, cell knockdown and overexpression of WWTR1 in hDPSCs. Group Ⅰ: hDPSCs from human teeth were further divided into youth group (15-25 years old) and group middle-aged group (40-50 years old) according to different ages. Group Ⅱ: according to different passage, hDPSCs were divided into young cells group (hDPSCs were transmitted to P3 generation), and old cells group (hDPSCs were transmitted to P10 generation). Group Ⅲ: hDPSCs were knocked down of WWTR1, which were further divided into knockdown group and knockdown carrier group. Group Ⅳ: hDPSCs were overexpressed of WWTR1, which were further divided into overexpression group and overexpression carrier group. Real-time fluorescence quantitative PCR (RT-qPCR) was used to detect the changes of WWTR1 expression in groups Ⅰ and Ⅱ, and cell counting kit-8 (CCK-8) was used for groups Ⅱ, Ⅲ, and Ⅳ. Cell proliferation capacity was detected by CCK-8 assay. The ability of osteogenic differentiation was detected by alizarin red staining. Cell senescence positive rate was detected by age-related β-galactosidase staining. The expression levels of age-related genes p53 and p21 were detected by RT-qPCR.Results:The proportion of senescent cells increased gradually with continuous culture. The proliferation and osteogenic differentiation of hDPSCs in the old group were significantly lower than those in the young group ( P<0.001). The expression levels of senescence related genes p53 (2.09±0.24) and p21 (4.91±0.54) in old cell group were higher than those in young cell group respectively [p53: (1.08±0.09) and p21: (1.09±0.08)] ( P<0.01, P<0.001). The WWTR1 expression levels of hDPSCs in middle-aged group and old cells group were both decreased compared with those in young group and young cells group ( P<0.01). The proportion of senescent cells in knockdown group (44.50±2.42) was higher than that in knockdown carrier group (22.27±0.56) ( P<0.001). After knocking down WWTR1 in hDPSCs, the expression levels of age-related genes p53 and p21 were up-regulated ( P<0.001), and the abilities of proliferation and osteogenic differentiation in the knockdown group were lower than those in the knockdown carrier group ( P<0.001). The proportion of senescent cells in overexpression empty carrier group (20.40±0.79) was higher than that in overexpression group (10.07±0.61) ( P<0.001). After WWTR1 overexpression ins hDPSCs, the expression levels of age-related genes p53 and p21 were down-regulated, and the proliferation and osteogenic differentiation ability in overexpression group were higher than those in overexpression carrier group ( P<0.001). Conclusions:WWTR1 can inhibit the expression levels of age-related genes p53 and p21, thus delaying the aging process as well as promoting the proliferation and osteogenic differentiation of hDPSCs.

OBJECTIVES: This study aims to determine the effects of low-level laser (LLL) on the expression of interleukin-6 (IL-6), tumor necrosis factor (TNF)-α, osteoprotegerin (OPG), and receptor activator of nuclear factor-κB ligand (RANKL) in human periodontal ligament cells (HPDLCs) stimulated by high glucose; and identify the molecular mechanism of LLL therapy in the regulation of periodontal inflammation and bone remodeling during orthodontic treatment in diabetic patients. METHODS: HPDLCs were cultured in vitro to simulate orthodontic after loading and irradiated with LLL therapy. The cultured cells were randomly divided into four groups: low glucose Dulbecco's modification of Eagle's medium (DMEM)+stress stimulation (group A), high glucose DMEM+stress stimulation (group B), hypoglycemic DMEM+LLL therapy+stress stimulation (group C), and hyperglycemic DMEM+LLL therapy+stress stimulation (group D). Groups C and D were further divided into C1 and D1 (energy density: 3.75 J/cm²) and C2 and D2 (energy density: 5.625 J/cm²). Cells in groups A, B, C, and D were irradiated by LLL before irradiation. At 0, 12, 24, 48, and 72 h, the supernatants of the cell cultures were extracted at regular intervals, and the protein expression levels of IL-6, TNF-α, OPG, and RANKL were detected by enzyme-linked immunosorbent assay. RESULTS: 1) The levels of IL-6 and TNF-α secreted by HPDLCs increased gradually with time under static pressure stimulation. After 12 h, the levels of IL-6 and TNF-α secreted by HPDLCs in group A were significantly higher than those in groups B, C1, and C2 (P<0.05), which in group B were significantly higher than those in groups D1, and D2 (P<0.01). 2) The OPG protein concentration showed an upward trend before 24 h and a downward trend thereafter. The RANKL protein concentration increased, whereas the OPG/RANKL ratio decreased with time. Significant differen-ces in OPG, RANKL, and OPG/RANKL ratio were found among group A and groups B, C1, C2 as well as group B and groups D1, D2 (P<0.05). CONCLUSIONS 1) In the high glucose+stress stimulation environment, the concentrations of IL-6 and TNF-α secreted by HPDLCs increased with time, the expression of OPG decreased, the expression of RANKL increased, and the ratio of OPG/RANKL decreased. As such, high glucose environment can promote bone resorption. After LLL therapy, the levels of IL-6 and TNF-α decreased, indicating that LLL therapy could antagonize the increase in the levels of inflammatory factors induced by high glucose environment and upregulate the expression of OPG in human HPDLCs, downregulation of RANKL expression in HPDLCs resulted in the upregulation of the ratio of OPG/RANKL and reversed the imbalance of bone metabolism induced by high glucose levels. 2) The decrease in inflammatory factors and the regulation of bone metabolism in HPDLCs were enhanced with increasing laser energy density within 3.75-5.625 J/cm². Hence, the ability of LLL therapy to modulate bone remodeling increases with increasing dose.
Humans ; Osteoprotegerin ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/pharmacology* ; RANK Ligand/pharmacology* ; Periodontal Ligament/metabolism* ; Lasers ; Glucose/pharmacology*

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.