Restoring colistin sensitivity in colistin-resistant Salmonella and Escherichia coli: combinatorial use of berberine and EDTA with colistin.

The appearance and prevalence of multidrug-resistance (MDR) Gram-negative bacteria (GNB) have limited our antibiotic capacity to control bacterial infections. The clinical efficacy of colistin (COL), considered as the "last resort" for treating GNB infections, has been severely hindered by its increased use as well as the emergence and prevalence of mobile colistin resistance (MCR)-mediated acquired drug resistance. Identifying promising compounds to restore antibiotic activity is becoming an effective strategy to alleviate the crisis of increasing MDR. We first demonstrated that the combination of berberine (BBR) and EDTA substantially restored COL sensitivity against COL-resistant Salmonella and Escherichia coli. Molecular docking indicated that BBR can interact with MCR-1 and the efflux pump system AcrAB-TolC, and BBR combined with EDTA downregulated the expression level of mcr-1 and tolC. Mechanically, BBR combined with EDTA could increase bacterial membrane damage, inhibit the function of multidrug efflux pump, and promote oxidative damage, thereby boosting the action of COL. In addition, transcriptome analysis found that the combination of BBR and EDTA can accelerate the tricarboxylic acid cycle, inhibit cationic antimicrobial peptide (CAMP) resistance, and attenuate Salmonella virulence. Notably, the combination of BBR and EDTA with COL significantly reduced the bacterial load in the liver and spleen of a mice model infected with Salmonella. Our findings revealed that BBR and EDTA can be used as adjuvants collectively with COL to synergistically reverse the COL resistance of bacteria. IMPORTANCE: Colistin is last-resort antibiotic used to treat serious clinical infections caused by MDR bacterial pathogens. The recent emergence of transferable plasmid-mediated COL resistance gene mcr-1 has raised the specter of a rapid worldwide spread of COL resistance. Coupled with the fact of barren antibiotic development pipeline nowadays, a critical approach is to revitalize existing antibiotics using antibiotic adjuvants. Our research showed that berberine combined with EDTA effectively reversed COL resistance both in vivo and in vitro through multiple modes of action. The discovery of berberine in combination with EDTA as a new and safe COL adjuvant provides a therapeutic regimen for combating Gram-negative bacteria infections. Our findings provide a potential therapeutic option using existing antibiotics in combination with antibiotic adjuvants and address the prevalent infections caused by MDR Gram-negative pathogens worldwide.

Contribution of microbial necromass to soil organic carbon formation during litter decomposition under incubation conditions.

We conducted a 512-day incubation experiment to study the dynamics of microbial necromass and soil carbon fraction in the 'litter-soil' transformation interface soil layer (TIS) during litter decomposition, using a perennial C3 herb, Stipa bungeana, in the loess hills. The results showed that soil microbial necromass was dominated by fungi in the early and middle stages, and by bacteria in the late stage. The contribution of fungal necromass C to mineral-associated organic C (MAOC) was significantly higher (38.7%-75.8%) than that of bacteria (9.2%-22.5%) and 2-3 times more than the contribution rate of bacterial necromass. Soil organic C (SOC) content was decreasing during litter decomposition. The input of plant C resources stimulated microbial utilization of soil C fractions. The continuous decrease in particulate organic C during the early and late stages of decomposition was directly responsible for the decrease in SOC content. In contrast, the fluctuating changes in microbial necromass C and MAOC played an indirect role in the reduction of SOC. The increase in soil microbial necromass C caused by a single exogenous addition of litter did not directly contribute to SOC accumulation.

Fixed-Time Synchronization of Competitive Neural Networks With Multiple Time Scales.

In this brief, we investigate the fixed-time synchronization of competitive neural networks with multiple time scales. These neural networks play an important role in visual processing, pattern recognition, neural computing, and so on. Our main contribution is the design of a novel synchronizing controller, which does not depend on the ratio between the fast and slow time scales. This feature makes the controller easy to implement since it is designed through well-posed algebraic conditions (i.e., even when the ratio between the time scales goes to 0, the controller gain is well defined and does not go to infinity). Last but not least, the closed-loop dynamics is characterized by a high convergence speed with a settling time which is upper bounded, and the bound is independent of the initial conditions. A numerical simulation illustrates our results and emphasizes their effectiveness.

Distributed Event-Triggered Synchronization of Interconnected Linear Two-Time-Scale Systems With Switching Topology.

This article investigates the synchronization problem of interconnected linear two-time-scale systems (TTSSs) with switching topology. By utilizing the Chang transformation, a distributed synchronization protocol is proposed with event-triggered communication. Static and dynamic event-triggered mechanisms are proposed successively, which both contain two separated event-triggering conditions corresponding to the slow and the fast subsystems. The existence of a strictly positive time period between any two successive transmissions is ensured regardless of the initial states. The main difficulty of this study lies in that the state jump and parametric uncertainty appear because of the system transformation. To overcome the difficulty, the system is first modeled as an uncertain hybrid system. Then, the control gain is properly designed by solving Riccati-like equations dependent on the rough bounds of the eigenvalues of communication graph Laplacians, and a piecewise quadratic Lyapunov function is proposed with which the jump caused by the switching topology is subtly evaluated. Sufficient conditions are thus established to achieve the event-triggered synchronization. Furthermore, the results are also extended to solve the synchronization problem of the interconnected impulsive linear TTSSs. Finally, three numerical examples are provided to demonstrate the effectiveness of the proposed theoretical results.

Molecular Characterization of a Novel Integrative Conjugative Element ICEHpa1 in Haemophilus parasuis.

ICEHpa1 was identified in the genome of a serovar 8 Haemophilus parasuis ST288 isolate YHP170504 from a case of swine lower respiratory tract infection. The aim of the present study was to characterize the integrative conjugative element ICEHpa1 and its multiresistance region. Susceptibility testing was determined by broth microdilution and the complete ICEHpa1 was identified by WGS analysis. The full sequence of ICEHpa1 was analyzed with bioinformatic tools. The presence of ICEHpa1, its circular intermediate and integration site were confirmed by PCR and sequence analysis. Transfer of ICEHpa1 was confirmed by conjugation. ICEHpa1 has a size of 68,922 bp with 37.42% GC content and harbors 81 genes responsible for replication and stabilization, transfer, integration, and accessory functions, as well as seven different resistance genes [bla Rob- 3, tet(B), aphA1, strA, strB, aac(6)'-Ie-aph(2')-Ia, and sul2]. Conjugation experiments showed that ICEHpa1 could be transferred to H. parasuis V43 with frequencies of 6.1 × 10-6. This is the first time a multidrug-resistance ICE has been reported in H. parasuis. Seven different resistance genes were located on a novel integrative conjugative element ICEHpa1, which suggests that the ICEHpa1 is capable of acquiring foreign genes and serving as a carrier for various resistance genes.

Characterization of pTS14, an IncF2:A1:B1 Plasmid Carrying tet(M) in a Salmonella enterica Isolate.

The objective of this study was to explore the genetic and biological features of the tet(M)-harboring plasmid pTS14 in Salmonella enterica strain S14 isolated from a chicken fecal sample. Plasmid pTS14 was identified by conjugation, S1-pulsed-field gel electrophoresis (PFGE), Southern hybridization, and plasmid sequencing. The biological characteristics of pTS14 were assessed via stability, growth kinetics, and starvation survival experiments. Strain S14, belonging to ST3007, harbored a 119-kb tet(M)-bearing IncF2:A1:B1 conjugative plasmid pTS14. The plasmid pTS14 contained a novel transposon Tn6709 with the genetic structure IS26-tnpA1-tnpA2-Δorf13-LP-tet(M)-tnpX-ΔtnpR-IS26, and the resistance genes tet(B), tet(D), strAB, sul2, and bla TEM-1b. In addition, pTS14 was found to be highly stable in the recipient strain E. coli J53. The transconjugant TS14 exhibited a higher survival ratio than E. coli J53 under permanent starvation-induced stress. The tet(M)-bearing IncF2 epidemic plasmid lineage may accelerate the dissemination of tet(M) and other genes by coselection, which could constitute a potentially serious threat to clinical treatment regimens.

Approximating the maximum tibial coverage in total knee arthroplasty does not necessarily result in implant malrotation.

Traditionally, the practice of the tibial component placement in total knee arthroplasty has focused on achieving maximum coverage without malrotation. However, the concept of maximizing coverage has not been well defined or researched and yet biased results are often produced. This study aimed to evaluate the effect of a prioritizing maximum coverage positioning strategy on the rotational alignment by using a strict computer algorithm. Computed tomographic scans of 103 tibial specimens were used to reconstruct three-dimensional tibia models. A virtual surgery was performed to generate the resection plane with a posterior slope of 7° on the proximal tibia. Symmetrical and anatomical tibial components were placed and analyzed with an automated program designed for approximating the maximum coverage based on the coherent point drift algorithm. We found that the average tibial coverage achieved across all specimens and implants was 85.62 ± 3.65%, ranging from 83.64 ± 4.10% to 86.69 ± 3.07%. When placed for maximal tibial coverage, the mean degree of rotation related to the Insall line was - 0.73° ± 4.53° for all subjects, 23% of the tibial components were malrotated. The average percentage position of the baseplate anteroposterior axis over the patellar tendon was 26.95 ± 14.71% from the medial edge. These results suggest that with specific design and proper placement of the component, approximating the maximum tibial coverage in total knee arthroplasty does not necessarily result in implant malrotation. The current tibial baseplates have shown good performance on the coverage when aligned parallel to the Insall line with the anteroposterior axis positioned between the medial 1/3 and medial 1/6 of the patella tendon.

Unconventional CN vacancies suppress iron-leaching in Prussian blue analogue pre-catalyst for boosted oxygen evolution catalysis.

The incorporation of defects, such as vacancies, into functional materials could substantially tailor their intrinsic properties. Progress in vacancy chemistry has enabled advances in many technological applications, but creating new type of vacancies in existing material system remains a big challenge. We show here that ionized nitrogen plasma can break bonds of iron-carbon-nitrogen-nickel units in nickel-iron Prussian blue analogues, forming unconventional carbon-nitrogen vacancies. We study oxygen evolution reaction on the carbon-nitrogen vacancy-mediated Prussian blue analogues, which exhibit a low overpotential of 283 millivolts at 10 milliamperes per square centimeter in alkali, far exceeding that of original Prussian blue analogues and previously reported oxygen evolution catalysts with vacancies. We ascribe this enhancement to the in-situ generated nickel-iron oxy(hydroxide) active layer during oxygen evolution reaction, where the Fe leaching was significantly suppressed by the unconventional carbon-nitrogen vacancies. This work opens up opportunities for producing vacancy defects in nanomaterials for broad applications.

Surgical treatment of severe multilevel circumferential compressive myelopathy of the cervical spine: is circumferential procedure necessary?

OBJECTIVE: To determine the necessity of circumferential decompression and fusion in patients with severe multilevel cervical spondylotic myelopathy with circumferential cord compression. METHODS: This prospective study involved 51 patients with severe multilevel circumferential cervical myelopathy underwent two-stage circumferential procedure between July 2008 and June 2010. VAS scores, satisfaction surveys and JOA scores and imaging studies were obtained. Twenty-three patients (45.1%) underwent two-stage surgery (group A); the other 28 patients (54.9%) were satisfied with the outcomes after first-stage surgery, and the second-stage surgery was avoided (group B). Age, sex and symptom duration did not differ between the groups. RESULTS: Patients were followed up for 3-5 years (mean, 42.5 months). In group A, VAS and JOA scores significantly improved from 63.3 and 7.9 to 38.3 and 10.4, respectively, at 3 months after the first-stage operation and 10.2 and 12.7, respectively, at 3 months after the second-stage operation. In group B, the VAS and JOA scores significantly improved from 62.7 and 7.9 to 31.1 and 11.2 respectively, at 3 months and 18.2 and 12.4, respectively at 6 months. Patient satisfaction rate significantly increased from 43.5% after the first-stage operation to 82.6% after the second-stage operation in group A. In group B, this rate was 89.3%. In group A, cervical spine lordosis increased from 12.8° preoperatively to 18.5° (p < .0001) and 19.1° (p > .05) at 3 months after the first-stage and second-stage operations, respectively. In group B, lordosis significantly increased from 12.5° preoperatively to 18.8° at 3 months. The total complication rate did not significantly differ from the rates after a single surgery (either anterior or posterior). CONCLUSION: Only 45.1% patients required surgery via both approaches. Therefore, a two-stage procedure is a rational choice and safe procedure. If outcomes are unsatisfactory after the first-stage operation, a second-stage operation can be performed.

Percutaneous Vertebroplasty Versus Conservative Treatment in Aged Patients With Acute Osteoporotic Vertebral Compression Fractures: A Prospective Randomized Controlled Clinical Study.

STUDY DESIGN: A prospective randomized clinical trial. OBJECTIVE: In this study, we determine whether percutaneous vertebroplasty (PVP) offers extra benefits to aged patients with acute osteoporotic vertebral compression fractures (OVCFs) over conservative therapy (CV). SUMMARY OF BACKGROUND DATA: OVCFs are common in the aged population with osteoporosis. While the optimal treatment of aged patients with acute OVCFs remains controversial, PVP, a minimally invasive procedure, is a treatment option to be considered. METHODS: Patients aged at 70 years or above with acute OVCF and severe pain from minor or mild trauma were assigned randomly to PVP and CV groups. The primary outcome was pain relief as measured by VAS score in 1-year follow-up period. The second outcome was quality of life assessed with ODI and Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO). Patient satisfaction surveys were also recorded. RESULTS: A total of 135 patients were enrolled, and 107 (56 in PVP group; 51 in CV group) completed 1-year follow-up. In PVP group, the vertebroplasty procedure was performed at a mean of 8.4 ±â€Š4.6 days (range, 2-21 days) after onset. Vertebroplasty resulted in much greater pain relief than did conservative treatment at postoperative day 1 (P < 0.0001). At every time point of follow-up, pain relief and quality of life were significantly improved in PVP group than in CV group at 1 week, 1 month, 3 months, 6 months, and 1 year (all P < 0.0001). The final follow-up surveys indicated that patients in PVP group were significantly more satisfied with given treatment (P < 0.0001). In addition, lower rate of complications was observed in PVP group (P < 0.0001). CONCLUSION: In aged patients with acute OVCF and severe pain, early vertebroplasty yielded faster, better pain relief and improved functional outcomes, which were maintained for 1 year. Furthermore, it showed fewer complications than conservative treatment. LEVEL OF EVIDENCE: 2.

An RCT study comparing the clinical and radiological outcomes with the use of PLIF or TLIF after instrumented reduction in adult isthmic spondylolisthesis.

OBJECTIVE: We prospectively compared posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) used in adult isthmic spondylolisthesis (IS) after surgical reduction with pedicle screws. METHODS: Between January 2009 and December 2010, 66 adult patients with single-level IS were randomly assigned to two groups treated using the PLIF technique (PLIF group, n = 34) and the TLIF technique (TLIF group, n = 32). Both groups were followed up for an average of 30.5 months (range 24-48 months). Clinical outcomes were assessed using the visual analog scale (VAS), Oswestry disability index (ODI) and Japanese orthopedic association (JOA) scores. Radiographic outcomes included percentage of vertebral slippage, focal lordosis and disk height. Clinical and radiographic outcomes were compared between the two groups. RESULTS: The average operative time and blood loss during surgery were significantly more in PLIF group than in TLIF group. Spondylolisthesis, disk height and focal lordosis were significantly improved postoperatively in both groups. There was no obvious difference in clinical outcomes, as assessed using the VAS, ODI and JOA scores, and radiographic outcomes. In PLIF group, there were two cases of neuropathic pain after surgery. CONCLUSIONS: After instrumented reduction of adult IS, either PLIF or TLIF can provide good clinical and radiological outcomes. With a single cage, TLIF was superior to PLIF in terms of surgical time and blood loss, but these differences may not be clinically relevant.

Continuous irrigation and drainage for early postoperative deep wound infection after posterior instrumented spinal fusion.

STUDY DESIGN: A retrospective study of clinical cases. PURPOSE: To evaluate the efficacy of continuous irrigation and drainage for early postoperative deep wound infection after posterior instrumented spinal fusion. SUMMARY OF BACKGROUND DATA: Aggressive debridement and irrigation has been recommended to treat postoperative wound infections after instrumented spinal fusion. However, this method of management, indicating repeating visits to the operating room until the wound is clean enough for closure, often results in prolonged hospitalization, increased cost, and sometimes compromise of the desired outcome. We hypothesize that repeat visits to the operating room for debridements can be avoided by aggressive debridements and primary closure with continuous irrigation and drainage for postoperative wound infections. METHODS: From 2004 to 2009, 23 patients with early postoperative deep wound infections after spinal fusion with instrumentation were surgically treated with thorough debridement and primary closure with continuous irrigation and drainage. All patients were followed up for 30.6 months (range, 24-54 mo). RESULTS: The mean duration of irrigation was 12.0 days (range, 7-16 d). In 21 patients (91.3%), the wound healed after continuous irrigation. The removal of the instrumentation or cages was not required in any case. Spinal fusion was achieved in all cases, except 1, where the patient developed a pseudoarthrosis at the L4-L5 level after L4-S1 fusion. The mean ODI for these 23 patients improved significantly from 53.4±18.7 preoperatively to 18.3±11.2 at the final follow-up visit (P<0.001). The mean JOA scores increased significantly from 15.5±4.1 preoperatively to 24.3±3.8 at the final follow-up (P<0.001). CONCLUSIONS: Continuous irrigation and drainage is an effective and safe method for the treatment of early postoperative deep wound infection after posterior instrumented spinal fusion.

Luteolin decreases the attachment, invasion and cytotoxicity of UPEC in bladder epithelial cells and inhibits UPEC biofilm formation.

Urinary tract infection (UTI), primarily caused by uropathogenic Escherichia coli (UPEC), is one of the most common infectious diseases worldwide. Emerging antibiotic resistance requires novel treatment strategies. Luteolin, a dietary polyphenolic flavonoid, has been confirmed as a potential antimicrobial agent. Here, we evaluated the sub-MICs of luteolin for potential properties to modulate the UPEC infection. We found that luteolin significantly decreased the attachment and invasion of UPEC J96 or CFT073 in human bladder epithelial cell lines T24. Meanwhile, obvious decreased expression of type 1 fimbriae adhesin fimH gene, lower bacterial surface hydrophobicity and swimming motility, were observed in luteolin-pretreated UPEC. Furthermore, luteolin could attenuate UPEC-induced cytotoxicity in T24 cells, which manifested as decreased activity of lactate dehydrogenase (LDH). Simultaneously, the inhibition of luteolin on UPEC-induced cytotoxicity was confirmed by ethidium bromide/acridine orange staining. Finally, the luteolin-pretreated UPEC showed a lower ability of biofilm formation. Collectively, these results indicated that luteolin decreased the attachment and invasion of UPEC in bladder epithelial cells, attenuated UPEC-induced cytotoxicity and biofilm formation via down-regulating the expression of adhesin fimH gene, reducing the bacterial surface hydrophobicity and motility.

Single segment of posterior lumbar interbody fusion for adult isthmic spondylolisthesis: reduction or fusion in situ.

OBJECTIVE: We prospectively compared surgical reduction or fusion in situ with posterior lumbar interbody fusion (PLIF) for adult isthmic spondylolisthesis in terms of surgical invasiveness, clinical and radiographical outcomes, and complications. METHODS: From January 2006 to June 2008, 88 adult patients with isthmic spondylolisthesis who underwent surgical treatment in our unit were randomized to reduced group (group 1, n = 45) and in situ group (group 2, n = 43), and followed up for average 32.5 months (range 24-54 months). The clinical and radiographical outcomes were compared between the two groups. RESULTS: The average operative time and blood loss during surgery showed insignificant difference (p > 0.05) between two groups. The radiological outcomes were significantly better in group 1, but there was no significant difference between two groups of clinical outcomes, depicting as VAS, ODI, JOA and patients' satisfaction surveys. Incident rate of surgical complications was similar in two groups, but in group 1 the complication seemed more severe because of two patients with neurological symptoms. CONCLUSIONS: For the adult isthmic spondylolisthesis without degenerative disease in adjacent level, single segment of PLIF with pedicle screw fixation is an effective and safe surgical procedure regardless of whether additional reduction had been conducted or not. Better radiological outcome does not mean better clinical outcome.

Posterior lumbar interbody fusion for aged patients with degenerative spondylolisthesis: is intentional surgical reduction essential?

BACKGROUND CONTEXT: Surgical reduction and posterior lumbar interbody fusion (PLIF) is commonly used to recover segmental imbalance in degenerative spondylolisthesis. However, whether intentional reduction of the slipped vertebra during PLIF is essential in aged patients with degenerative spondylolisthesis remains controversial. PURPOSE: We compared the outcomes of surgical reduction and fusion in situ among aged patients who underwent PLIF for degenerative spondylolisthesis. STUDY DESIGN: A prospective randomized clinical trial on the surgical treatment of degenerative spondylolisthesis patients aged older than 70 years. PATIENT SAMPLE: Between January 2006 and December 2009, 73 patients aged 70 years or older with single-level degenerative spondylolisthesis requiring surgical treatment were included in this study. OUTCOME MEASURES: Clinical outcomes were assessed using the visual analog scale, Oswestry Disability Index, and Japanese Orthopedic Association scores. Radiographic outcomes included percentage of vertebral slippage, focal lordosis, and disc height. METHODS: The 73 patients were randomly assigned to two groups treated using surgical reduction (Group A, n=36) and fusion in situ (Group B, n=37). Both groups were followed up for an average of 33.2 months (range, 24-54 months). The clinical and radiographic outcomes were compared between the two groups. RESULTS: Surgical complications were similar in the two groups. The average operative time and blood loss during surgery did not insignificantly differ (p>.05) between the two groups. Spondylolisthesis, disc height, and focal lordosis were significantly improved postoperatively in both groups. There was no obvious difference in clinical outcomes, as assessed using the visual analog scale, Oswestry Disability Index, and Japanese Orthopedic Association scores, although the radiographic outcomes were considerably better in Group A than in Group B. CONCLUSIONS: Posterior lumbar interbody fusion with pedicle screws fixation, with or without intraoperative reduction, provides good outcomes in the surgical treatment of aged patients with degenerative spondylolisthesis. Better radiological outcomes by intentional reduction do not necessarily indicate better clinical outcomes.

[The prevalence of congenital heart disease in students of Liangshan prefecture in Sichuan province].

OBJECTIVE: To investigate the congenital heart disease (CHD) prevalence of students in Liangshan prefecture in Sichuan province, and to explore the risk factors of CHD. METHODS: Stratified cluster sampling was conducted in collecting demographic data. Heart auscultation was used to screening the CHD, and colour Doppler flow imaging was used to diagnose the CHD. RESULTS: A total of 10,021 student were collected in this study. About 19.74% of total cases had cardiac murmur. Sixty-eight students were diagnosed as CHD through colour Doppler flow imaging, accounting for 0.68%. In addition, the top three ranks of CHD were atrial septal defect, patent ductus arteriosus, interventricular septal defect. Our study also found that per capita income of CHD families was lower than non-CHD families, meanwhile, the CHD prevalence of Yi nationality was higher than other nationalities. There was no statistical significance in age, gender, height, weight, body mass index, head circumference, waist circumference between different types of CHD. CONCLUSIONS: The CHD prevalence of students in Liangshan prefecture has been in a high level in China; therefore we need pay more attention on screening for the CHD.

Hypermethylation of TGF-ß1 gene promoter in gastric cancer.

AIM: To examine transforming growth factor-ß1 (TGF-ß1) promoter methylation in gastric cancer and to determine if Helicobacter pylori (H. pylori) or interleukin (IL)-1ß could induce TGF-ß1 hypermethylation in vitro. METHODS: We examined the frequency and extent of TGF-ß1 promoter methylation using methylation-specific PCR in the gastric tissues from 47 gastric cancer patients and 39 non-gastric cancer subjects. H. pylori infection was confirmed by a positive result from either a serological test, histological analysis or C¹³ urea breath test. GES-1 and MKN-45 cells co-cultured with H. pylori or treated with IL-1ß for 12, 24 and 48 h in vitro tested the effects of H. pylori or IL-1ß on TGF-ß1. RESULTS: Twenty-four/forty-seven (51%) cases of gastric cancer (GC) tissues showed TGF-ß1 promoter methylation, 15/47 (31.9%) cases of matched non-cancerous gastric mucosa tissues from the GC patients, and 11/39 (28%) case of the normal gastric mucosa tissues from non-GC subjects showed TGF-ß1 promoter methylation (51% vs 28%, P < 0.05). Significantly higher levels of methylation of TGF-ß1 were found in the tumor tissues than in non-tumor tissues from GC patients (0.24 ± 0.06 vs 0.17 ± 0.04, P < 0.05) and normal gastric tissues from non-GC subjects (0.24 ± 0.06 vs 0.15 ± 0.03, P < 0.05). TGF-ß1 methylation was found in 48.3% of H. pylori-positive gastric mucosal tissues whereas only 23.1% of H. pylori-negative gastric mucosal tissues showed TGF-ß1 methylation (48.3% vs 23.1%, P < 0.05). IL-1ß appeared to induce a dose-dependent methylation of TGF-ß1 and the strongest methylation was observed in GES-1 cells treated with 2.5 ng/mL of IL-1ß for 48 h. Further studies showed that pre-treatment of GES-1 cells with 20 ng/mL IL-1RA for 1 h could partially abolish the effect of IL-1ß on TGF-ß1 methylation. Infection of GES-1 cells by H. pylori was not found to induce significant TGF-ß1 promoter methylation. CONCLUSION: Our data revealed that TGF-ß1 promoter is methylated in GC patients. IL-1ß may be an important mediator for H. pylori induced gene methylation during GC development.

[Post antibiotic, post beta-lactamase inhibitor and post antibiotic sub-MIC effect of ceftriaxone/tazobactam on beta-lactamase-producing Escherichia coli in vitro].

OBJECTIVE: To study post antibiotic effect (PAE), post beta-lactamase inhibitor effect (PLIE) and post antibiotic sub-MIC effect (PASME) of ceftriaxone/tazobactam on beta-lactamase-producing Escherichia coli in vitro. METHODS: The minimal inhibitory concentration (MIC) of ceftriaxone/tazobactam against 4 types of beta-lactamase producing E. coli strains, was measured by two-fold agar dilution method. The numbers of CFU on plates were counted by micro-inoculation colony counting method. The growth kinetics curves of the bacteria were drawn according to CFU counts, from which the PAE, PLIE and PASME were calculated. RESULTS: The MIC of the ceftriaxone/tazobactam combination was eight times more than ceftriaxone alone. No longer PAE (-0.59-0.85 h) was found in the ceftriaxone/tazobactam combination or any of them alone. The PLIE and PASME varied according to the type of beta-lactamase but similar results were observed for the strains producing the same type beta-lactamase. All PLIEs (0.62-3.22 h) and most PASMEs (0.12-5.61 h) were longer than PAEs. The lower MIC of ceftriaxone the strain had, the longer the PAE, PLIE and PAMSE were. CONCLUSION: The duration of PLIE and PASME may concerned with the type of beta-lactamase. With both longer PLIE and PASME, longer dosing interval should be recommended. The PAE, PLIE and PASME provide an important instrument for pharmacodynamic studies of antibiotics, in particular for the design of dosing schedules.

Extraordinary acoustic transmission through a 1D grating with very narrow apertures.

Recently, there has been an increased interest in studying extraordinary optical transmission (EOT) through subwavelength aperture arrays perforated in a metallic film. In this Letter, we report that the transmission of an incident acoustic wave through a one-dimensional acoustic grating can also be drastically enhanced. This extraordinary acoustic transmission (EAT) has been investigated both theoretically and experimentally, showing that the coupling between the diffractive wave and the wave-guide mode plays an important role in EAT. This phenomenon can have potential applications in acoustics and also might provide a better understanding of EOT in optical subwavelength systems.

[BCG cell wall proteins enhance clearance of Pseudomonas aeruginosa in rat lungs].

OBJECTIVE: To test the function of BCG cell wall proteins in enhancing the clearance of Pseudomonas aeruginosa in rat lungs. METHODS: The BCG cells were broken by supersonic technique. The cell wall proteins were isolated by discontinues sucrose density-gradient centrifugation, and fractionated by Sephadex G-150 chromatography. The relative molecular mass of the isolated proteins was analyzed by SDS-PAGE. The hBD-1 gene mRNA expression in the SPC-A-1 cells was identified by Northern blot and RT-PCR. The cell wall component was injected intraperitoneally to the rats. Forty eight hours later, 5 X 10(6) CFU of P. aeruginosa ATCC27853 or Staphylococcus aureus ATCC25923 were inoculated via trachea. The bacteria colony in the supernatant of the homogenated lungs of the rats was counted 24 hours after the inoculation. RESULTS: Two protein components of BCG cell wall were fractionated. The relative molecular mass of component 2 was in the range of 18 X 10(3) -30 X 10(3). The hBD-1 mRNA expression detected by Northern blot was markedly enhanced by the stimulation of heat-inactivated BCG whole cells. The BCG-induced hBD-1 mRNA expression in the SPC-A-1 cells detected by RT-PCR was mainly contributed by fraction 2 of the BCG cell wall proteins. The bacteria decreased significantly in the lungs of the rats with the injection of BCG component 2 (n=8, P<0. 01). CONCLUSION: The fraction (relative molecular mass is 18 X 10(3) -30 X 10(3)) of BCG cell wall proteins improve the defense of rat lungs against P. aeruginosa infection.