Objective This study analyzes the risk points in the quality control of bioink and the main processes of bioprinting,clarifies and explores the quality control and supervision model for bioprinting medical devices,and provides theoretical and practical guidance to ensure the safety and effectiveness of bioprinting medical devices.Methods The quality control risk points throughout the bioprinting process were comprehensively analyzed,with a particular focus on bioprinting materials and key processes.The regulatory model and methods for bioprinting medical devices were examined.This research concentrated on critical technologies such as extrusion,laser-assisted,and in situ bioprinting,assessing their potential for clinical applications and regulatory challenges.Results Bioink from different sources should meet regulatory requirements.It is essential to ensure aseptic handling of raw materials and to validate sterilization under"worst-case"conditions.Conclusion As bioprinting technology advances rapidly,corresponding research into materials,processes,and quality risk control should be conducted to ensure the concurrent development of the regulatory system.This will continuously contribute to the orderly progression of the entire industry and human health.

Osteoporotic vertebral compression fracture (OVCF) can lead to lower back pain and may be even accompanied by scoliosis, neurological dysfunction and other complications, which will affect the daily activities and life quality of patients. Vertebral augmentation is an effective treatment method for OVCF, but it cannot correct unbalance of bone metabolism or improve the osteoporotic status, causing complications like lower back pain, limited spinal activities and vertebral refracture. The post-operative systematic and standardized rehabilitation treatments can improve curative effect and therapeutic efficacy of anti-osteoporosis, reduce risk of vertebral refracture, increase patient compliance and improve quality of life. Since there still lack relevant clinical treatment guidelines for postoperative rehabilitation treatments following vertebral augmentation for OVCF, the current treatments are varied with uneven therapeutic effect. In order to standardize the postoperative rehabilitation treatment, the Spine Trauma Group of the Orthopedic Branch of Chinese Medical Doctor Association organized relevant experts to refer to relevant literature and develop the "Guideline for postoperative rehabilitation treatment following vertebral augmentation for osteoporotic vertebral compression fracture (2022 version)" based on the clinical guidelines published by the American Academy of Orthopedic Surgeons (AAOS) as well as on the principles of scientificity, practicality and advancement. The guideline provided evidence-based recommendations on 10 important issues related to postoperative rehabilitation treatments of OVCF.

Objective To improve the diagnosis and treatment of hip gouty arthritis.Methods Retrospective analysis of cases of gouty arthritis from 2014 January to 2017 March was conducted.Patients with gouty arthritis were divided into hip joint group and common joint group (without invaded hip) and hip joint group was further divided into acute group and chronic group.Clinical data of each group were compared.Results Compared with common joint group,hip joint group usually combined with obesity or previous ipsilateral hip trauma history.Male patients in hip joint group were younger and the patients with unilateral hip involvement were without obvious local swelling,heat and pain.CT scan and sonography can provide assistance for early diagnosis and operation or pathological diagnosis was needed for the confirmation when necessary.Conclusions Hip gouty arthritis lacks specific diagnostic criteria in clinic,and is easily confused with other diseases associated with hip.Therefore,the possibility of the hip gouty arthritis should be taken into consideration when the diagnosis of the hip disease is not clear.

Objective In the present study, we investigated the effects of advanced oxidation protein products(AOPP) on reactive oxygen species(ROS) production in murine osteoblastic MC3T3-E1 cells by NADPH oxidase enzymes pathway. Methods Experiments were divided into three groups, including control group, rats albumin(RSA) group, and AOPP group. Different concentrations of AOPP were added to the osteoblastic MC3T3-E1 cells culture medium. The production of ROS in MC3T3-E1 cells was measured by the fluorescence intensity of intracellular fluoroprobe ( DCFD ) . In order to verify the effect of enzyme of the production of ROS, the specific inhibitors of corresponding enzymes were added in the MC3T3-E1 cells which were cultured in the medium with AOPP. Finally, western blot and immunofluorescence were used to observe the changes of NADPH oxidase enzymes subunits. Results Different concentrations of AOPP (50,100,200μg/ml) induced MC3T3-E1 cells to produce different amount of ROS. The higher concentrations of AOPP were added, the more ROS were produced. Furthermore,200μg/ml AOPP induced the maximum amount of ROS production(P<0. 05). Meanwhile, AOPP induced MC3T3-E1 cells to produce different amount of ROS with a time-dependent manner. The peak amount of ROS production in MC3T3-E1 cells was observed in 3h when AOPP were added (P<0. 05). In addition, when specific inhibitors of corresponding enzymes were added in the MC3T3-E1 cells, the production of ROS were significantly suppressed by C-SOD, DPI, and apocynin(P<0. 05). On the other hand, AOPP can up-regulate the expression of Nox4 protein of the MC3T3-E1 cells, which is one of the subunits of NADPH oxidase enzymes. Meanwhile, AOPP can also induce the membrane migration of p47phox subunit. Conclusion AOPP induces osteoblastic MC3T3-E1 cells to produce ROS by NADPH oxidase enzymes pathway, and which may be one of the pathogenesis of AOPP involved in osteoporosis.

Objective:To compare the quality of the canal isthmus retropreparation among three ultrasonic retrotips.Methods:120 maxillary bicuspid teeth with 2 canals and an isthmus were randomly assigned to 3 groups(n =40).The canal isthmus were retro-preparated by ultrasonic Ni-Ti tip RE2,diamond tip Berutti and #25K file respectively.The quality of cavity margin,the number and type of the micro-cracks were evaluated by SEM.Data were statistically analysed by Kruskal Wallis Test of SPSS 13.0.Results:The cavity margin quality of ultrasonic Ni-Ti tip RE2 group was superior to that of other 2 groups(P =0.003);The number of micro-crack in Ni-Ti tip RE2 group was less than that of other 2 groups(P =0.003).The type of micro-cracks has no significant difference among the 3 groups(P =0.830).Conclusion:Ultrasonic Ni-Ti tip RE2 is feasible in the canal isthmus retropreparation.

Objective To modify a classic two-vessel occlusion (2VO) modeling method in order to decrease the systematic errors in the behavioral experiments such as Morris water maze.Methods Thirty-two adult male Wistar rats were randomly allocated into classic 2VO model,modified model,sham operation and sham ligation groups (n =8 in each group).Only the bilateral common carotid arteries were ligated in the classic 2VO model group; the common carotid arteries were clipped intermittently,and the origins of pterygopalatine arteries of the internal carotid arteries were high selectively ligated in the modified model group; the common carotid arteries were only ligated intermittently in the sham ligation group; and only the common carotid arteries and the upper segment of pterygopalatine artery branches were separated in the sham operation group.The rat behavior was evaluated using the pupillary light reflex,Morris water maze and eight-arm radial maze.HE staining was used to observe the histological changes.Results The Morris water maze escape latency (F =72.169 - 163.102,all P ＜ 0.001) and the number of reference memory errors of eight-arm radial maze (F =33.515-74.726,all P ＜0.001) in the modified model and the classic 2VO model groups were longer and higher than those in the sham operation group.The pupillary light reflex of the rats was lost in the classic 2VO model group and the pupillary light reflex of the rats was normal in other groups.The reaching platform time in the classic 2VO model group was significantly longer than that in the modified model and sham operation groups (P ＜0.001).The percentage of target quadrant dwell time was also decreased significantly (at day 7 after procedure:F =13.770,P ＜0.001 ; at day 90 after procedure:F =14.780,P ＜0.001).HE staining showed pathological changes such as the cells decrease in hippocampal CA1 region and leukoaraiosis in the modified model and the classic 2VO model groups.In addition,there were more vacuole-like changes in the rat optic nerve region in the classic 2VO model group,while there were no such changes in the modified model group.Conclusions Establishing vascular dementia model with permanent occlusion of bilateral internal carotid arteries after intermittent occlusion of bilateral carotid arteries could avoid severe visual impairment in rats.In the Morris water maze and eight-arm maze test,the modified model rats showed significant decrease in learning and memory abilities and had hippocampal damage.

Powdery mildew (Pm) caused by the infection of Blumeria graminis f.sp.tritici (Bgt) is a worldwide crop disease resulting in significant loss of wheat yield.To profile the genes and pathways responding to the Bgt infection,here,using Affymetrix wheat microarrays,we compared the leaf transcriptomes before and after Bgt inoculation in two wheat genotypes,a Pm-susceptible cultivar Jingdong 8 (S) and its near-isogenic line (R) carrying a single Pm resistant gene Pm30.Our analysis showed that the original gene expression status in the S and R genotypes of wheat was almost identical before Bgt inoculation,since only 60 genes exhibited differential expression by P =0.01 cutoff.However,12 h after Bgt inoculation,3014 and 2800 genes in the S and R genotype,respectively,responded to infection.A wide range of pathways were involved,including cell wall fortification,flavonoid biosynthesis and metabolic processes.Furthermore,for the first time,we show that sense-antisense pair genes might be participants in wheat-powdery mildew interaction.In addition,the results of qRT-PCR analysis on several candidate genes were consistent with the microarray data in their expression patterns.In summary,this study reveals leaf transcriptome changes before and after powdery mildew infection in wheat near-isogenic lines,suggesting that powdery mildew resistance is a highly complex systematic response involving a large amount of gene regulation.

Objective:To compare the quality of root-end preparation quantitatively between ultrasonic retrotips and traditional slow-speed handpiece. Methods: 27 maxillary second bicuspid teeth with two canals and an isthmus were randomly assigned to 3 groups.Root-end preparations were made respectively using ultrasonic diamond tip Berutti and niti tip RE2, ultrasonic 40~#K file and slow-speed handpiece with No.2 round bur. Image processing and analysis system were used to measure the preoperation and postoperation parameters for further evaluating the difference between the two techniques. Results: The cutting volume of ultrasonic instruments was less than slow-speed handpiece(P<0.000 1). Conclusion: Ultrasonic instrument is better in the root-end preparation than traditional slow-speed handpiece.

To explore the possibility and condition of differentiation of bone marrow mesenchymal cells (BMSCs) to neural cells in vitro, BMSCs from whole bone marrow of rats were cultured. The BMSCs of passage 3 were identified with immunocytochemical staining of CD44 ( + ), CD71 ( + )and CD45(-). There were type Ⅰ and type Ⅱ cells in BMSCs. Type Ⅰ BMSCs were spindleshaped and strong positive in immunocytochemical staining of CD44 and CD71, whereas flat and big type Ⅱ BMSCs were lightly stained. The BMSCs of same passage were induced to differentiate into neural cells by β-mercaptoethanol (BME). After induction by BME, the type Ⅰ BMSCs withdrew to form neuron-like round soma and axon-like and dendrite-like processes, and were stained positively for neurofilament (NF). The type Ⅱ BMSCs did not change in the BME medium and were negatively or slightly stained of NF.

OBJECTIVE:To study the characteristics of ceftazidime-resistant?-lactamase produced by Escherichia coli.METHODS:The types of2strains of drug fast?-lactamase produced by Escherichia coli were determined initially by K-B slip diffusion method and ampholine electrophoresis method;The plasmid was extracted by alkaline lysis and the PCR ampli?fication and sequencing were conducted;?-Lactamase was counter-extracted by saturated ammonium sulfate,filtrated by Sephadex G-75gel and purified by DE-52anion exchange chromatography;The molecular weight of which was determined by SDS-PAGE and the enzyme kinetics parameters of?-lactamas were determined by ultraviolet spectrophotometry.RE?SULTS:The2strains produced a super-broad spectrum?-lactamase(CTX-M-1V)with isoionic point at8.7and the molecular weight at29kDa,which can hydrolyze cefotaxim and aztreonam but imipenem and which was sensitive to sulbactam(IC 50 =94nmol/L)and tazobactam(IC 50 =5nmol/L).CONCLUSION:CTX-M-1V is a CTX-M type super-broad spectrum?-lactamase sensitive to suppressants.