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BACKGROUND:Additive manufacturing technology provides strong technical support for personalized and precise medical treatment due to its rapid prototyping,digitalization,and personalization.Therefore,its medical devices have developed rapidly in orthopedics,oral,preoperative planning,craniomaxillofacial,and other clinical applications. OBJECTIVE:To briefly introduce the progress of additive manufacturing technology and its commercial application in the clinic in and outside China. METHODS:Wanfang Data,China National Knowledge Infrastructure(CNKI),PubMed,Elsevier,Springer Link databases,and the websites of National Medical Products Administration and FDA were searched using"additive manufacturing,medical device,clinical application,3D printing"as Chinese search terms and"additive manufacturing(AM),additive manufacturing technology,medical device,clinical application,3D printing"as English search terms.The search time ranged from January 2010 to March 2023,and a few classical long-term articles were included. RESULTS AND CONCLUSION:Additive manufacturing technology is classified by the form of raw materials(liquid-based,solid-based,and powder-based).At present,there are seven kinds of additive manufacturing processes,including fused deposition molding,stereo-curing molding,powder bed melting,directed energy deposition,binder jet 3D printing,inkjet printing,and layered solid manufacturing.The marketed additive manufacturing products include orthopedic products,dental products,preoperative planning guide plate/bone model products,and craniomaxillofacial products.The orthopedic products include matching long-segment bone defect restoration,interbody fusion cage,knee joint orthosis,vertebral prosthesis,thoracolumbar fusion matching prosthesis system,knee prosthesis,and hip prosthesis.Dental products include light-curing resin for additive manufacturing and BB Base 3D Printing Resin for Denture Base.The products of preoperative planning guide plates/bone models include bone models,medical orthopedic surgical guide plates,customized dental implant guide plates,and human organ models.The craniomaxillofacial products include polycaprolactone scaffolds,patient-specific skull implants,OsteoFab patient-specific face device,SpinFab VBR prosthesis,and TruMatch CMF titanium alloy 3D printing prosthesis system.
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OBJECTIVE@#To assess the value of non-invasive prenatal testing (NIPT) for the identification of numerical and structural chromosomal abnormalities and copy number variations (CNVs) in fetuses.@*METHODS@#46 197 pregnant women undergoing NIPT at the Prenatal Diagnosis Center of Chenzhou First People's Hospital from January 2018 to December 2021 were selected as the study subjects. Positive cases were subjected to chromosomal karyotyping and copy number variation sequencing (CNV-seq) following amniocentesis.@*RESULTS@#Nearly 50% of common chromosomal aneuploidies were found in the elder pregnant women. Among these, sex chromosome aneuploidies were mainly found in pregnant women with advanced age as well as borderline risks by serological screening. Rare autosomal aneuploidies and CNVs were mainly found in those with borderline or high risks by serological screening. The positive predictive values (PPV) for fetal chromosomal abnormalities indicated by NIPT were as follows: T21 (92.37%, 109/118), T18 (53.85%, 14/26), sex chromosome aneuploidies (45.04%, 59/131), T13 (34.62%, 9/26), CNVs (29.17%, 14/48), and rare autosomal aneuploidies (2.60%, 2/77).@*CONCLUSION@#NIPT has a high detection rate for T21, T18, T13 and sex chromosome aneuploidies. It can also detect rare autosomal aneuploidies and CNVs, including some rare structural abnormalities, though verification is required by analyzing amniotic fluid samples.
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Gravidez , Feminino , Humanos , Variações do Número de Cópias de DNA , Aberrações Cromossômicas , Transtornos Cromossômicos/genética , Aneuploidia , FetoRESUMO
In recent years, emerging technology medical devices have developed rapidly. How to more scientifically and more efficiently regulate these novel medical devices so as to improve access to advanced medical technology while ensuring safety and effectiveness is a new challenge faced by regulatory authorities, and is also the core topic of regulatory science. New tools, new standards and new methods are important means to achieve regulatory science. "Medical Device Development Tool" proposed by the U.S. FDA is a novel medical device regulatory science tool, which can help medical device developers to predict and evaluate product performance more efficiently. It is also helpful for regulatory authorities to make regulatory decisions more efficiently. This study introduces the concept, qualification process, role of MDDT in medical device regulation and MDDT examples, and makes some discussion on the device evaluation from the perspective of reliability and validity. MDDT can facilitate the developing of novel medical device.
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Estados Unidos , Legislação de Dispositivos Médicos , Reprodutibilidade dos Testes , United States Food and Drug Administration , Tecnologia , Aprovação de EquipamentosRESUMO
BACKGROUND@#Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. The ubiquitin-specific peptidase 25 (USP25) protein has been reported to participate in the development of several cancers. However, few studies have reported its association with HCC. In this study, we aimed to investigate the function and mechanism of USP25 in the progression of HCC.@*METHODS@#We analyzed USP25 protein expression in HCC based on The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) database cohorts. Then, we constructed USP25-overexpressing and USP25-knockdown HepG2, MHCC97H, and L-O2 cells. We detected the biological function of USP25 by performing a series of assays, such as Cell Counting Kit-8 (CCK-8), colony formation, transwell, and wound healing assays. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were performed to detect the interaction between USP25 and the Wnt/β-catenin signaling pathway. The relationship between USP25 and tripartite motif-containing 21 (TRIM21) was assessed through mass spectrometry and co-immunoprecipitation (Co-IP) analysis. Finally, we constructed a mouse liver cancer model with the USP25 gene deletion to verify in vivo role of USP25.@*RESULTS@#USP25 was highly expressed in HCC tissue and HCC cell lines. Importantly, high expression of USP25 in tissues was closely related to a poor prognosis. USP25 knockdown markedly reduced the proliferation, migration, and invasion of HepG2 and MHCC97H cells, whereas USP25 overexpression led to the opposite effects. In addition, we demonstrated that USP25 interacts with TRIM21 to regulate the expression of proteins related to epithelial-mesenchymal transition (EMT; E-cadherin, N-cadherin, and Snail) and the Wnt/β-catenin pathway (β-catenin, Adenomatous polyposis coli, Axin2 and Glycogen synthase kinase 3 beta) and those of their downstream proteins (C-myc and Cyclin D1). Finally, we verified that knocking out USP25 inhibited tumor growth and distant metastasis in vivo .@*CONCLUSIONS@#In summary, our data showed that USP25 was overexpressed in HCC. USP25 promoted the proliferation, migration, invasion, and EMT of HCC cells by interacting with TRIM21 to activate the β-catenin signaling pathway.
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Animais , Camundongos , beta Catenina/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/patologia , Ubiquitina Tiolesterase/metabolismo , Via de Sinalização Wnt/genéticaRESUMO
The status of lymph node metastasis is an important prognostic factor for many malignant tumors, including lung cancer. In the 8th edition of the TNM staging system for lung cancer, the T staging had obvious changes and refinements, but the N staging had little changes. Recently, several studies have found that the prognosis of patients with the same N stage can vary greatly, suggesting that a more detailed subgroup of patients with the same N stage should be subdivided, including the inclusion of extra-capsular lymph node metastases (ENE). In this review, we reviewed the definition, classification/grading, imaging diagnosis, pathological diagnosis, related molecular markers and their relationship with the prognosis of lung cancer patients.
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From the perspective of technical evaluation, this article introduces the focus of clinical evaluation of dental implants (systems) in comparison with the comparable devices and discusses the clinical evaluation of such products,combined with the clinical evaluation review of dental implants (systems) products in recent years, in order to provide reference for the registration of these products.
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Implantes DentáriosRESUMO
The evolution throughout the whole supervision history of Class II/III safety and effectiveness related NMPA submission dossier requirements was studied in this study, meanwhile elaborating the revolution progress of clinical evaluation domestically. The relationship between submission dossier requirements and Essential Principles of Safety and Performance of Medical Devices as well as IMDRF relevant documents was deeply analyzed and illustrated, in order to comprehensively understanding the background and future reform direction of NMPA submission dossier requirements under the background of the government's deepening reform of medical device evaluation and approval system strategy.
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Humanos , China , Aprovação de EquipamentosRESUMO
Objective To explore the effects of triclosan (TCS) on the immune function of mice. Methods Forty male and female Kunming mice (25±2 g) were selected. The animals were divided into 5 groups according to body weight ratio, including a blank control (saline solution) group, dimethyl sulfoxide (DMSO) group, and three triclosan solution groups (59.375 mg/kg, 118.75 mg/kg, and 237.5 mg/kg, respectively). There were 8 mice in each group, half male and half female. Animals were treated with TCS by intragastric administration once a day for two weeks. Upon the completion of the treatment, animals were sacrificed, the spleen, thymus and other tissues were collected, and the ratios of their weight to body weigh were calculated. The peripheral blood was taken by eye-ball removal method, and the half hemolysis value was determined. Results Compared with the positive control group, the spleen index of male mice in the medium dose group and high dose group increased significantly (P < 0.05), and the spleen index of female mice in the high dose group showed significant difference (P < 0.05). Compared with the positive control group, the thymus index of male high dose group was significantly different (P < 0.05). The thymus indexes of female high, medium, and low dose groups all were significantly different compared to the control group (P < 0.05). HC50 results showed that the HC50 of both male and female mice decreased (P < 0.05). Conclusion High concentration of triclosan can inhibit the immune function of Kunming mice.
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Objective@#To examine whether the long-term resting heart rate (RHR) pattern can predict the risk of cardiovascular and cerebrovascular diseases (CVDs).@*Methods@#This prospective cohort study included 63 040 participants who took part in the health examination in 2006 and one of the health examinations on 2008 or 2010 and were free of myocardial infarction, stroke, arrhythmia, cancer and not treated with β-recepter blocker. The outcomes were the first occurrence of myocardial infarction and stroke during the follow up ended on December 31, 2015. RHRs were measured in 2006, 2008, and 2010. We used latent mixture modeling SAS Proc procedure to identify RHR trajectories. We identified 4 distinct RHR trajectory patterns based on the data derived from 2006 and on the pattern change during 2006 to 2010 (low-stable, moderate-stable, moderate-increasing, elevated-decreasing). Collected the general clinical data of the patients. Cox regression model was used to determine the association between RHR trajectory patterns and the risk of CVDs during follow up. Hazard ratio (HR) with 95% confidence intervals (CI) were calculated using Cox regression modeling.@*Results@#There were statistical significance among the 4 distinct RHR trajectory patterns on the following variables: age, gender, smoking status, drinking status, physical activity, education status, history of use antihypertensive drugs, history of hypertension,history of diabetes, body mass index, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting blood glucose, and the level of high-sensitivity C-reactive protein (all P<0.01). The moderate-increasing pattern experienced the highest risk of developing stroke and CVDs among all 4 patterns. The cumulative incidence of cerebral infarction, cerebral hemorrhage and CVDs in the order of low-stable trajectory, moderate-stable trajectory and moderate-increasing trajectory. The cumulative incidences of cerebral infarction, cerebral hemorrhage and CVDs in elevated-decreasing trajectory group were significantly lower than those in moderate-increasing trajectory group, but higher than those in moderate-stable trajectory group. Compared to the low-stable pattern, adjusted HR was 1.3 (95%CI 1.0-1.6) for the moderate-increasing pattern after adjustment for potential confounders.@*Conclusion@#Our study finds that individuals with moderate-increasing RHR trajectory pattern are associated with higher risk of cardiovascular and CVDs.
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Objective To explore the folate receptor alpha(FRA)expression in different types and stages of in endometrial carcinoma(EC). The sensitivity and specificity of FRA testing were compared with CA125 to evaluate its diagnostic performance.Methods Serum from 50 cases of EC patients and 30 cases of normal patients was collected.Tissue from 83 cases of typeⅠEC and 30 cases of normal endometrium and typeⅡEC were collected. The expression of serum FRA was detected by ELISA.The expression ofserum CA125 was detected by electrochemi-luminescence.The expression of FRA and CA125 in tissues was detected by immunohistochemistry. Results The rate of elevated FRA expression of in typeⅠEC tissue was higher than that in typeⅡEC(P < 0.05). The rate of elevated FRA expression in type I EC was higher than that in the early stage(P < 0.05). The ROC curve showed that the sensitivity and specificity of FRA was higher than these of CA125′s. Further,they are higher in the com-bined serum FRA and CA125.Conclusions This study shows that the FRA expression level in endometrial carci-noma varies in different subtypes,indicating the potential different pathogeneses. The rate of elevated FRA expression in type I endometrial carcinoma was higher than that in the early stage. This provides the possibility for the application of FRA targeted fluorescent developer in advanced endometrial carcinoma meticulous surgery. Combination of FRA and CA125 have better diagnostic value in detecting EC.
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Objective To observe c-Fos expression in visual cortex of infant rhesus monkeys with myopia induced by hyperopic defocus and preliminarily investigate the possibility of visual cortex participating in myopia. Methods Eight SPF grade healthy infant rhesus monkeys aged 20 to 30 days were randomly divided into hyperopic defocused group and control group,4 monkeys for each group. The monkeys in hyperopic defocused group wore -3 D spectacle lenses. The monkeys in control group wore 0 D lenses. The monkeys' refractive error,corneal topography, vitreous chamber depth were measured at the start of lens wear and at 2,4,6,8,12 weeks post-treatment. At 12 weeks post-treatment,the visual cortex tissues were removed for c-Fos protein measurement by immunohistochemistry and Western blot assays. The results were analyzed semiquantitatively to compare the differences of c-Fos expression between hyperopic defocused group and control group. The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. This study protocol was approved by Ethic Committee of Zhongshan Ophthalmic Center ( No. 2013-014). Results After 12 weeks'lens wear,the vitreous chamber elongation amplitude of hyperopic defocused group monkeys was more obvious than that of the control group ([0.93±0.24]mm vs. [0.72±0.09]mm;t=2.292,P=0.047). The decrease of hyperopic degrees of hyperopic defocused group monkeys was more obvious than that of the control group ([-3.23± 1.36]D vs. [-1.55±0.52]D;t=-3.273,P=0.006). The eyes of hyperopic defocused group monkeys appeared a remarkable myopic shift after treatment. The number of c-Fos immunoreactive neurons was less in the hyperopic defocused group than that in the control group,with a statistically significant difference between them ([1 843±191]/mm2vs. [2 296±503]/mm2;t=2.381,P=0.041). Western blot assay showed that the optical density of c-Fos protein in the hyperopic defocused group was significantly less than that in the control group (0.50±0.17 vs. 0.99± 0.22;t=-4.982,P<0.01). Conclusions Hyperopic defocus,as an abnormal visual stimulus,can induce the onset of myopia in infant rhesus monkeys and inhibit c-Fos expression in visual cortex. Visual cortex may participate in myopia induced by hyperopic defocus.
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Recently, the registration of artificial hip prosthesis products increased year by year. In the new version of the provisions for medical device registration, the domestic or import of such products in the registration declaration may need to complete a clinical trial in the country. How to carry out scientific clinical trials of the product design is the common concern of enterprises and clinical trial institutions. To review the guideline and literature concerning registration for artificial hip prosthesis, the focus on clinical trial design of artificial hip prosthesis include clinical inclusion, evaluation standard, sample size. Through the discussion, we hope to provide advice and guidance for clinical trials of this kind of products.
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Artroplastia de Quadril , Ensaios Clínicos como Assunto , Prótese de Quadril , Desenho de Prótese , Sistema de Registros , Resultado do TratamentoRESUMO
In the progress of viral hepatitis, lymphocytes migrate and infiltrate liver tissues, which is relevant to antiviral therapy.However, the related mechanism is still poorly understood.In recent years,CXC chemokine ligand (CXCL)10 and its receptor CXCR3 have been extensively studied.The interaction between CXCL10 and CXCR3 would be a breakthrough point for study of the mechanism of viral hepatitis pathogenesis.This article reviews the research advances of CXCL10 in the progression of viral hepatitis and in the evaluation of antiviral therapy.
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Objective To explore the expression and the pathomechanism of folate receptor alpha(FRα) and CA125 in the development and progression of endometrial carcinoma.Methods Sixty samples of endometrial carcinoma tissues,46 samples of endometrial hyperplasia tissues and 10 normal endometrial tissues were collected in the study.Immunohistochemical methods were used to detect the expression of Frαand CA125 in all tissues.The expressions of FRα and CA125 and their correlation with clinicopathological characteristics were analyzed.Results FRα was positively expressed in 93.9% of the endometrial carcinoma tissues,with a strongly positive rate of 65.0%,which was significantly higher than that in endometrial hyperplasia tissues and normal endometrial tissues (P < 0.05).The highly expressed FRαin endometrial carcinoma tissues was associated with age,FIGO stage and histologic types (P < 0.05),while no statistical significance was found between the high expression of FRαand myometrial invasion.The expression of FRα in endometrial atypical hyperplasia was higher than that in other hyperplasia subgroups.The expression of CA125 in endometrial carcinoma tissues and endometrial hyperplasia tissues were both higher than that in normal endometrial tissues (P < 0.05).Conclusion FRα may play an important role in the carcinogenesis and progression of endometrial carcinoma,and act as a target of therapy and a kind of assessment for prognosis in endometrial carcinoma.CA125 may be involved in the development of endometrial lesions and further researches are needed to confirm a physiological mechanism between FRA and CA125 in carcinogenesis of endometrial carcinoma.
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Objective@#To test whether the tryptophan metabolism was abnormal in newly diagnosed ITP patients as well as in these patients after treatment with dexamethasone.@*Methods@#Newly diagnosed patients with ITP between Jan 2014 and May 2015 were enrolled, including 14 females and 11 males, with a median age of 57 years and a median PLT count of 16 (0-32) ×109/L. All patients were treated with oral dexamethasone. The expression levels of IDO mRNA and TTS mRNA in peripheral blood mononuclear cells (PBMC) were analyzed by real-time quantitative polymerase chain reaction. ELISA was used to test the concentrations of IDO and TTS in serum. The concentrations of plasma kynurenine and tryptophan were detected by high-pressure liquid chromatography. Samples from healthy individuals were tested as controls.@*Results@#①After dexamethasone treatment, 17 patients resulted in persistent remission, 2 cases were ineffective, and relapse occurred in 6 cases at a median follow-up of 11 (6-18) months. ②Before and after dexamethasone treatment, the relative expression of indoleamine2,3-dioxygenase (IDO) mRNA and tryptophanyl t-RNA synthetase (TTS) mRNA showed that there were significant decline in persistent remission group (2.54±0.86 vs 19.85±5.36, t=3.188, P=0.003; 0.68±0.19 vs 45.39±15.83, t=2.842, P=0.008) , compared with the normal control group, the difference was not statistically significant (t=2.313, P=0.027; t=1.127, P=0.268) . After treatment, the IDO concentration decreased [ (19.34±0.42) U/ml] and the TTS concentration was markedly increased [ (13.37±0.54) μg/L] in sustained remission group compared with that before treatment [ (21.91±0.37) U/ml] as well as that in normal controls. In particularly, abnormal tryptophan catabolism could be recovered in these 17 patients with persistent remission [Try: (19.85±5.36) μmol/L vs (19.65±4.55) μmol/L, t=1.027, P=0.311; Kyn: (0.56±0.26) μmol/L vs (0.58±0.23) μmol/L, t=2.075, P=0.448]. ③There was no obviously difference in the relative expression of IDO mRNA and TTS mRNA, the concentration of IDO and TTS and the abnormal tryptophan catabolism between before and after treatment of dexamethasone in patients without response and relapsed patients (all P>0.01) .@*Conclusion@#The tryptophan catabolism was abnormal in ITP patients, and it could be recovered in patients with persistent remission.
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<p><b>OBJECTIVE</b>To explore the prognostic significance of monosomal karyotype (MK) in patients with acute myeloid leukemia (AML).</p><p><b>METHODS</b>The clinical data of 498 AML patients were analyzed retrospectively.</p><p><b>RESULTS</b>Of 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].</p><p><b>CONCLUSION</b>MK was an independent adverse prognostic factor in AML patients.</p>
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Humanos , Cariótipo Anormal , Cariotipagem , Leucemia Mieloide Aguda , Monossomia , Prognóstico , Estudos RetrospectivosRESUMO
Intracranial artery stenosis is one of the main causes inducing transient ischemic attack (TIA) or cerebral ischemic stroke. Being a minimally-invasive and reliably-effective technique, intracranial artery stent angioplasty has brought about a new approach for the treatment of intracranial artery stenosis , and thus provides more opportunities to the patients who are not suitable for intracranial vascular bypass surgery. However, the higher occurrence of perioperative complications caused by stent angioplasty should be seriously taken into consideration by clinical physicians. In order to reduce the occurrence of complications , in this paper the perioperative complications of stent angioplasty for intracranial artery stenosis are analyzed , and the therapeutic strategies as well as the proper approaches are discussed.
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Objective To investigate the clinical features, risk factors, diagnose, treatments and prognosis of patients with hepatitis B virus (HBV)-related liver failure complicated with invasive pulmonary aspergillosis (IPA). Methods A case-control study was performed to retrospectively analyze the clinical data of 43 patients with HBV-related liver failure complicated with IPA. A cohort of 43 patients with HBV-related liver failure complicated with bacterial infection only was analyzed at the same time and another cohort of 43 patients with HBV-related liver failure without any infections served as the control group. Results Compared with the control group, patients with infection had lower platelet counts and prothrombin activity, higher scores of model for end-stage liver disease (MELD), especially the patients with IPA (F=42.43,13.69,14, 22, all P<0.01). And the similar results were observed in patients with IPA group before and after Aspergillus infection (F= 12.09,14.52,-16.74, all P<0.01). Furthermore, the annual mortality was 100. 0% in patients with IPA,which was higher than that of patients complicated with bacterial infection only; and both groups were higher than control group of patients without infection. The statistic results showed that patients with longer length of stay, more antibiotics usage, and more invasive procedures were all risk factors of HBV-related liver failure complicated with IPA. Conclusions Conditions of patients with HBV-related liver failure deteriorate rapidly after complicated with IPA and patients have higher mortality and poorer prognosis.Therefore, it will be effective to enhance the recognition of the early clinical manifestations, and make diagnosis timely and treat with potent anti-fungal therapy to improve their survival.
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Objective To investigate the mechanism of quinolone resistance in Psendomonas aeruginosa.Methods The minimum inhibitory concentrations (MICs)of ciprofloxacin and levofloxacin with and without carbonylcyainde-m-chlorophenylhydrazone(CCCP)were determined by agar dilution method.Polymerase chain reaction(PCR)and DNA sequencing were used to study the mutations in quinolone resistance-determining region of gyrA and parC genes.The strains were genotyped by enterbacterial repetitive intergenie consensus-PCR(ERIC-PCR).Results Sixteen quinolones-resistant Pseudomonas aeruginosa strains were obtained.The MICs of ciprofloxacin and levofloxacin were not reduced significantly by adding CCCP.Thr-83→Ile of gyrA and Ser-87→Leu of parC were found simultaneously in 16 strains of resistant Pseudomonas aeruginosa.Analysis of ERIC-PCR products indicated that 16 quinolone-resistant strains had an identical band pattern which was different from that seen in the sensitive strains.Conclusion Mutations in gyrA and parC may be the main mechanism of quinolone resistance in clinical isolates of Pseudomonas aeruginosa.
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An efficient and repeatable approach in transforming the foxtail millet (Setaria italica ) using Agrobacterium LBA4404 horboring the plasmid pBI121 was established. Factors affecting transformation efficiency were investigated including the genotype, explants, the density of bacteria, the duration for inoculation and co-cultivation, and the concentration of acetosyringone in the medium. The maximum transformation conditions were: the callus induced from inflorescence was used as explant; the duration for inoculation with Agrobacterium at low cell density was 30-40 min; for the co-cultivation , the suitable concentration of acetosyringone in the medium was 0.1 mmol/L, and the duration was 2 days.