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Biomedical subjects

Fu Wang

Publications and source records attributed to Fu Wang.

At least 19 recordsLinked to original sources
PubMed2006

[Changes of antimicrobial resistance among clinical isolates of Escherichia coil in Shanghai 1990-2004].

OBJECTIVE: To investigate the trend of resistance to antimicrobial agents among clinical isolates of Escherichia coli 1990-2004. METHODS: Agar diffusion test was used to analyze the changes of drug susceptibility of 33,495 strains of E. coli isolated from 11 hospitals in Shanghai to 21 antimicrobial agents 1990-2004. RESULTS: The resistance rates of 33,495 E.coli isolates to 21 antimicrobial agents mostly increased 1990-2004. The resistance rates to ampicillin and piperacillin increased from 69% and 30% to 85% and 71.4% respectively. The resistance rates to cephalosporins, except ceftazidime and cefepime, all increased, e. g., the resistance rates to cefazolin (24.0%-->48.3%), cefuroxime (18.0%-->45.7%), and cefaclor (33.3%-->46.8%), especially that to cefotaxime (6.0%-->35.2%). The resistance rate to fluoroquinolones increased from 11.0% to 55.4%. The resistance rate to gentamicin increased from 44.0% to 54.0%. The resistance rates to tetracycline, chloramphenicol, SMZ/TMP remained at high levels. However, ceftazidime, cefepime, imipenem, amikacin, beta-lactams/beta-lactamase inhibitors, and nitrofurantoin remained active against the E.coli isolates. The detectable rate of extended-spectrum beta-lactamase-producing strains in E. coli increased from 14.7% to 36.5%. CONCLUSION: The trend of resistance of E. coli to commonly used antimicrobials was upward 1990-2004.

Anti-Bacterial Agents↗
PubMed2005

A peripheral element assembles the compact core structure essential for group I intron self-splicing.

The presence of non-conserved peripheral elements in all naturally occurring group I introns underline their importance in ensuring the natural intron function. Recently, we reported that some peripheral elements are conserved in group I introns of IE subgroup. Using self-splicing activity as a readout, our initial screening revealed that one such conserved peripheral elements, P2.1, is mainly required to fold the catalytically active structure of the Candida ribozyme, an IE intron. Unexpectedly, the essential function of P2.1 resides in a sequence-conserved short stem of P2.1 but not in a long-range interaction associated with the loop of P2.1 that stabilizes the ribozyme structure. The P2.1 stem is indispensable in folding the compact ribozyme core, most probably by forming a triple helical interaction with two core helices, P3 and P6. Surprisingly, although the ribozyme lacking the P2.1 stem renders a loosely folded core and the loss of self-splicing activity requires two consecutive transesterifications, the mutant ribozyme efficiently catalyzes the first transesterification reaction. These results suggest that the intron self-splicing demands much more ordered structure than does one independent transesterification, highlighting that the universally present peripheral elements achieve their functional importance by enabling the highly ordered structure through diverse tertiary interactions.

Base Pairing↗
PubMed2005

[Vascularized pedicle iliac crest for the repair of bone and soft tissue defect of lower extremity].

OBJECTIVE: To study the role of transplantation of the vascularized pedicle iliac crest for the repair of bone and soft tissue defect of lower extremity. METHODS: The vascularized pedicle iliac crest was designed for the repair of bone and soft tissue defect of lower extremity according to anatomic feature of leg and foot. Skin graft was used for coverage of the iliac flap. RESULTS: Skin survival could demonstrate the survival of the vascularized pedicle iliac crest indirectly one week postoperatively. Skin survived completely in 4 cases and partly in 3 cases. Callus was seen at the transplantation site one month postoperatively, and K-wires were removed 4 months later in the cases of metatarsal defect. The external fixators were removed in the cases of tibia defect 6 to 8 months postoperatively. The functions of lower extremities were restored in 2 to 4 months. The bone and soft tissue defects were repaired, and ultimate function and cosmetic effects were satisfied after the mean follow up of 10 months (ranged from 6 to 15 months). CONCLUSION: Transplantation of the vascularized pedicle iliac crest is an ideal method for the repair of bone and soft tissue defect of lower extremity. The operation can be performed in one stage. The functions and cosmetic effects are better than the traditional methods.

Adult↗
PubMed2005

Structural and photocatalytic properties of TiO2 films fabricated on silicon substrates by MOCVD method.

Silicon ( 111) and Silicon(100) were employed for fabrication of TiO2 films by metal organic chemical vapor deposition( MOCVD). Titanium(IV) isopropoxide(Ti[O(C3H7)4] ) was used as a precursor. The as-deposited TiO2 films were characterized with FE-SEM, XRD and AFM. The photocatalytic properties were investigated by decomposition of aqueous Orange II . And UV-VIS photospectrometer was used for checking the absorption characteristics and photocatalytic degradation activity. The crystalline and structural properties of TiO2 film had crucial influences on the photodegradation efficiency. For MOCVD in-situ deposited films on Si substrates, the photoactivities varied following a shape of "M": at lower(350 degrees C ), middle(500 degrees C ) and higher(800 degrees C ) temperature of deposition, relative lower photodegradation activities were observed. At 400 degrees C and 700 degrees C of deposition, relative higher efficiencies of degradation were obtained, because one predominant crystallite orientation could be obtained as deposition at the temperature of two levels, especially a single anatase crystalline TiO2 film could be obtained at 700 degrees C.

Azo Compounds↗
PubMed2004

Trichosanthin's interfacial interactions with phospholipids: a monolayer study.

Lipid monolayer at the air/water interface, as half a membrane, was used here to investigate the interaction between trichosanthin (TCS), a ribosome inactivating protein, and phospholipid membrane. First, the protein adsorption experiments showed that the negatively charged DPPG caused obvious enrichment of TCS beneath the monolayer, indicating electrostatic attraction between TCS and the negatively charged phospholipid. Second, when TCS was incorporated into the phospholipid monolayer, it could not be completely squeezed out until the monolayer collapsed. The results were demonstrated to be irrelative with the phospholipid headgroup, suggesting a strong hydrophobic force between TCS and phospholipid hydrocarbon chain was involved in the interaction. Third, the protein/membrane interaction was further studied with fluorescence microscope. The results showed that TCS could penetrate into both the condensed and the fluid phase of the DPPG monolayer under low pH condition and eventually resulted in a homogeneous phospholipid phase. The breakage of ordered packing of phospholipid by TCS may be responsible for this homogenizing effect.

Adsorption↗
PubMed2004

An Asian study on the prevalence of atypical respiratory pathogens in community-acquired pneumonia.

BACKGROUND: In many parts of Asia, the inaccessibility and high cost of diagnostic tests have hampered the study of community-acquired pneumonia (CAP) caused by atypical respiratory pathogens. OBJECTIVE: This surveillance study examined the frequency of infection with Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila in 1756 patients presenting with signs and symptoms of CAP at 12 medical centres in Asia, using standardised laboratory techniques and interpretation criteria in all participating centres. METHODS: Diagnosis of current infection was based on significant changes in antibody titer or persisting high antibody titers, together with the presence of bacterial DNA in respiratory secretions, in the case of M. pneumoniae and C. pneumoniae infections, or bacterial antigen in urine, in the case of L. pneumophila serogroup 1 infection. RESULTS: Using these criteria, results from 1374 patients with paired sera showed that, overall, 23.5% of CAP cases were associated with infection with atypical respiratory pathogens, with M. pneumoniae, C. pneumoniae, and L. pneumophila being found in 12.2%, 4.7%, and 6.6% of cases, respectively. Persisting high antibody titers indicative of past exposure to M. pneumoniae, C. pneumoniae, and L. pneumophila were seen in 10.2%, 4.8%, and 18.9% of patients, respectively. CONCLUSION: These data reflect the overall high prevalence of these atypical pathogens among Asian patients with CAP.

Adolescent↗
PubMed2004

[Identification and expression of blaCTX-M-14 and blaCTX-M-24].

OBJECTIVE: To identify the ESBL gene and the prevalence in Escherichia coli and Klebsiella pneumoniae strain isolated from Huashan Hospital, Shanghai. METHODS: Isolates were confirmed as an ESBL producing strain by double-disk synergy test and NCCLS Confirmatory Test. Antibiotic susceptibilities were determined by standard agar dilution procedure on Mueller-Hinton agar. To determine whether the resistance was transferable, the conjugation experiment was performed; plasmids were isolated from clinical isolates and transcojugants. The partial bla(gene) of ESBL producing isolates and their transcojugants were detected by PCR using universal primers for TEM, SHV, CTX-M-1group, Toho-1group, CTX-M-13group respectively. The entire bla(CTX-M-13) group were amplified by PCR using the primers outside the Open Reading Frame (ORF) of CTX-M-13group beta-lactamases; the PCR products of entire bla(CTX-M-13)group were cloned into vector and the recombinant plasmids were transformed into the recipient strain for expression; the PCR products were also directly sequenced and analyzed; the clinical isolates of ESBL producers were detected by PFGE. RESULTS: ESBL producers were resistant to most beta-lactams and non-beta-lactams. Most transconjugants were obtained at frequency of 10(-4) approximately 10(-5) and resistance to non-beta-lactams was cotransferred with the ESBL activity to the transconjugant. A plasmid of about > 23.1 kb was obtained from each tansconjugant by plasmid extraction. Partial gene amplification products of CTX-M-13 group gene were obtained from isolates and their transconjugants. The bla(CTX-M-13)group from 4 transconjugants were identified as bla(CTX-M-14), and other six were bla(CTX-M-24); those ESBLs were mediated by plasmids (> 23.1 kb); the transformants producing CTX-M-14 or CTX-M-24 were resistant to most beta-lactams, which were much more resistant to cefotaxime than to ceftazidine; PFGE patterns of those isolates were different. CONCLUSION: clinical isolate of Escherichia coli and Klebsiella pneumoniae isolated from Huashan Hospital, Shanhai produced CTX-M-14 or CTX-M-24, which caused the isolate resistant to most beta-lactams; no clone spread in those isolates was found.

Anti-Bacterial Agents↗
PubMed2004

In vitro activities of tigecycline against clinical isolates from Shanghai, China.

To evaluate the in vitro activity of tigecycline, the minimum inhibitory concentrations (MICs) of tigecycline against 1,201 strains of recent clinical isolates from 10 hospitals in Shanghai, China were determined and compared with selected comparators. Results showed that tigecycline had broad-spectrum antimicrobial activity. It was highly active against Gram-positive cocci, including methicillin-resistant Staphylococcus spp., penicillin-intermediate Streptococcus pneumoniae, Enterococcus faecalis and E. faecium. Tigecycline also had good activity against most strains of Enterobacteriaceae, Haemophilus influenzae, Neisseria gonorrhoeae, and Moraxella catarrhalis. However, it was poorly active against Acinetobacter baumannii and Pseudomonas aeruginosa. Tigecycline was highly active against anaerobic Gram-positive cocci such as Peptococcus spp. The in vitro activity of tigecycline was significantly better than that of minocycline and tetracycline. It was as active as or slightly more active than vancomycin and teicoplanin in the activity against resistant aerobic Gram-positive cocci. Tigecycline was bactericidal against all Gram-positive cocci tested except Enterococcus spp. Inoculum size but not pH of medium or concentration of human serum in broth had significant effect on the in vitro activity of tigecycline. Aged media (48-72 hours after preparation) used in the test and specific resistance problem in China may have some effects on MIC values of tigecycline.

Anti-Bacterial Agents↗
PubMed2004

A Klebsiella pneumoniae producing three kinds of class A beta-lactamases encoded by one single plasmid isolated from a patient in Huashan Hospital, Shanghai, China.

A Klebsiella pneumoniae strain was isolated from a sputum specimen of a patient in the intensive care unit in 1999 in Shanghai Huashan Hospital, China. The isolate was confirmed as an extended-spectrum beta-lactamase (ESBL) producing strain by double-disk synergy test. The results of susceptibility test showed that it was resistant to most beta-lactams (including third generation cephalosporins) and non-beta-lactam antimicrobial agents. Transconjugants were obtained at a frequency of 10(-4). A plasmid of about 60 kb was obtained from the transconjugant by plasmid extraction. Three major nitrocefin-hydrolysing bands with pIs of 5.4, 8.2 and 8.4, were shown in extracts of the transconjugant. Partial gene amplification products of bla(TEM), bla(SHV), and CTX-M-1 group gene were obtained from the isolate as well as its transconjugant. The entire bla(TEM), bla(SHV), and bla(CTX-M) in the transconjugant were amplified by PCR and the PCR products were cloned into a pHSG398 vector. Afterwards, the susceptibility of transformants and activities of beta-lactamases of transformants on antibiotics were tested. The PCR products were directly sequenced, analysed and identified as TEM-1, SHV-12, and CTX-M-3 genes. These results confirm that this strain of Klebsiella pneumoniae produces SHV-12, CTX-M-3 ESBLs and TEM-1 beta-lactamase, encoded by one single plasmid, which is responsible for the resistance of this strain to most beta-lactams.

Base Sequence↗
PubMed2003

Plasmid-mediated quinolone resistance in clinical isolates of Escherichia coli from Shanghai, China.

Although quinolone resistance usually results from chromosomal mutations, recent studies indicate that quinolone resistance can also be plasmid mediated. The gene responsible, qnr, is distinct from the known quinolone resistance genes and in previous studies seemed to be restricted to Klebsiella pneumoniae and Escherichia coli isolates from the University of Alabama in Birmingham, where this resistance was discovered. In Shanghai, the frequency of ciprofloxacin resistance in E. coli has exceeded 50% since 1993. Seventy-eight unique ciprofloxacin-resistant clinical isolates of E. coli from Shanghai hospitals were screened for the qnr gene by colony blotting and Southern hybridization of plasmid DNA. Conjugation experiments were done with azide-resistant E. coli J53 as a recipient with selection for plasmid-encoded antimicrobial resistance (chloramphenicol, gentamicin, or tetracycline) and azide counterselection. qnr genes were sequenced, and the structure of the plasmid DNA adjacent to qnr was analyzed by primer walking with a sequential series of outward-facing sequencing primers with plasmid DNA templates purified from transconjugants. Six (7.7%) of 78 strains gave a reproducible hybridization signal with a qnr gene probe on colony blots and yielded strong signals on plasmid DNA preparations. Quinolone resistance was transferred from all six probe-positive strains. Transconjugants had 16- to 250-fold increases in the MICs of ciprofloxacin relative to that of the recipient. All six strains contained qnr with a nucleotide sequence identical to that originally reported, except for a single nucleotide change (CTA-->CTG at position 537) encoding the same amino acid. qnr was located in complex In4 family class 1 integrons. Two completely sequenced integrons were designated In36 and In37. Transferable plasmid-mediated quinolone resistance associated with qnr is thus prevalent in quinolone-resistant clinical strains of E. coli from Shanghai and may contribute to the rapid increase in bacterial resistance to quinolones in China.

4-Quinolones↗
PubMed2003

The diagnosis and treatment of severe cerebral fat embolism.

OBJECTIVE: To improve the diagnosis and treatment of severe cerebral fat embolism (SCFE). METHODS: The data of nine patients with SCFE were retrospectively analyzed. The manifestations of the central nerve system, respiratory system and hemorrhage were recorded, at the same time, accessory examination including arterial oxygen, fat macroglobules in venous blood and image examination was adapted. The patients were treated with exopexy, pharmocotherapy and oxygentherapy. RESULTS: Two of the nine patients died of severe complications, the other seven recovered without severe sequela. CONCLUSIONS: Gurd standard should be improved for early diagnosis of SCFE. If svere complications can be prevented, patients who receive early treatment will have favourable prognosis.

Accidental Falls↗
PubMed2002

[Extended-spectrum beta-lactamase in Klebsiella pneumoniae and Escherichia coli isolates].

OBJECTIVE: To investigate the prevalence, drug resistance, gene typing, and epidemicity of extended-spectrum beta-lactamases (ESBL) Klebsiella pneumoniae and Escherichia coli isolates. METHODS: 559 strains of K. pneumoniae and 427 strains of E.coli were isolated form Huanshan Hospital from 1 January to 31 December 1999. The ESBL-producing strains were detected by double disc test and confirmed by minimal inhibitory concentration (MIC). The MIC of ESBL-producing strains was detected by agar dilution test. The beta-lactamase genes were detected by PCR. DNA fingerprinting was made by pulsed-field gel electrophoresis (PFGE). RESULTS: The incidence of ESBL-producing strains was 51% among the isolated K. pneumoniae (285/559) and 23.6% among the isolated E. coli (101/427), most of which were collected from the patients in the intensive care unit and neurosurgical ward. 63.5% of the ESBL-producing K. pneumoniae strains were collected from sputum specimens, and 64.3% of the ESBL-producing E. coli strains were collected from the urine specimens. Most ESBL-producing strains were resistant to most beta-lactam antibiotics, including the third-generation cephalosporins, and non- beta-lactam antimicrobial drugs, such as fluoroquinolones, aminoglycosides, tetracycline, and chloramphenicol. Most of the ESBL-producing strains were susceptible to imipenam, cefmetazole, and beta-lactam antibiotic/clavulanic acid. TEM type beta-lactamase was the main type among those EBSL-producing strains, followed by SHV type and CTX-M type. Some ESBL-producing E. coli and most ESBL-producing K. pneumoniae produced more than one type of beta-lactamase. CONCLUSION: ESBL-producing strains are common among hospital strains of E. coli and K. pneumoniae. Most of them are multidrug resistant. Prevalence and transmission of these strains exist in hospital.

Anti-Bacterial Agents↗
PubMed2002

Human apolipoprotein H may have various orientations when attached to lipid layer.

Apolipoprotein H (ApoH), also known as beta(2)-glycoprotein I, is a plasma glycoprotein with its in vivo physiological and pathogenic roles being closely related to its interaction with negatively charged membranes. Although the three-dimensional crystal structure of ApoH has been recently solved, direct evidence about the spatial state of ApoH on the membrane is still lacking. In this work, the interactions of ApoH with the lipid layer are studied by a combination of lipid monolayer approach and surface concentration determination. The spatial state of the orientation of ApoH on the lipid layer is investigated by analyzing the process of membrane-attached ApoH molecules being extruded out from the phospholipid monolayer by compression. The results show that on neutral lipid layer ApoH has an upright orientation, which is not sensitive to the phase state of the lipid layer. However, on acidic lipid layer, ApoH may have two forms of orientation. One is an upright orientation in the liquid phase region, and the other is flat orientation on the condensed domain region. The variation of the spatial state of ApoH on the lipid layer may relate to a variety of its physiological functions.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2002

Investigation of extended-spectrum beta-lactamase in Klebsiellae pneumoniae and Escherichia coli from China.

Extended-spectrum beta-lactamases (ESBLs) are an increasing cause of resistance to third-generation cephalosporins in Enterobacteriaceae. However, they have not been well studied in China. We investigated the prevalence, resistance, and probable gene type of ESBLs using MICs testing and polymerase chain reaction in 559 Klebsiellae pneumoniae and 427 Escherichia coli isolates collected from patients in Huashan Hospital from 1 January to 31 December 1999. The incidence of ESBL-producing strains was 51% among Klebsiellae pneumoniae (285/559) and 23.6% among Escherichia coli (101/427), most of which were collected from patients in intensive care unit and neurosurgical ward. PFGE showed that some epidemic ESBL-producing strains were present in the ICU, especially among ESBL-producing Klebsiellae pneumoniae. The major source of ESBL-producing Klebsiellae pneumoniae and Escherichia coli was sputum specimen (63.5%) and urine (64.3%), respectively. These strains were resistant to most beta-lactams (including the third-generation cephalosporins and monobactams) and non-beta-lactams (such as fluoroquinolones, aminoglycosides, tetracycline, and chloramphenicol), all or most ESBL producers were susceptible to imipenem, cefmetazole and beta-lactam/clavulanic acid. TEM was the main type of beta-lactamases and the CTX-M type of ESBLs was common in these isolates. Some ESBL-producing Escherichia coli and most ESBL-producing Klebsiellae pneumoniae produced more than one type of beta-lactamase. These data confirm that ESBL producers are common among hospital strains of Escherichia coli and Klebsiellae pneumoniae in China. It is important to monitor such strains closely and prevent their spread.

Anti-Bacterial Agents↗