Biomedical subjects

Fu-Huan Chao

Publications and source records attributed to Fu-Huan Chao.

12 recordsLinked to original sources

PubMed2006

Inhibition of hepatitis B virus by D-fraction from Grifola frondosa: synergistic effect of combination with interferon-alpha in HepG2 2.2.15.

In this study, D-fraction extracted from Grifola frondosa (GF-D) and its combination with human interferon alpha-2b (IFN) were investigated for the inhibitory effect on hepatitis B virus (HBV) in HepG2 2.2.15 cells (2.2.15 cells). HBV DNA and viral antigens were analyzed by a quantitative real-time polymerase chain reaction and end-point titration in radioimmunoassays, respectively. The results showed that GF-D or IFN alone could inhibit HBV DNA in 2.2.15 cells with the 50% inhibitory concentration (IC50) of 0.59 mg/ml and 1399 IU/ml, respectively. We further investigated the combination of GF-D and IFN for anti-HBV activity and found that they synergistically inhibited HBV replication in 2.2.15 cells. In combination with 0.45 mg/ml GF-D, the apparent IC50 value for IFN was 154 IU/ml. This 9-fold increase in antiviral activity of IFN suggested that GF-D could synergize with IFN. These results indicate that GF-D, in combination with IFN, might provide a potentially effective therapy against chronic HBV infections.

Antiviral Agents↗

PubMed2005

Detection and identification of intestinal pathogenic bacteria by hybridization to oligonucleotide microarrays.

AIM: To detect the common intestinal pathogenic bacteria quickly and accurately. METHODS: A rapid (<3 h) experimental procedure was set up based upon the gene chip technology. Target genes were amplified and hybridized by oligonucleotide microarrays. RESULTS: One hundred and seventy strains of bacteria in pure culture belonging to 11 genera were successfully discriminated under comparatively same conditions, and a series of specific hybridization maps corresponding to each kind of bacteria were obtained. When this method was applied to 26 divided cultures, 25 (96.2%) were identified. CONCLUSION: Salmonella sp., Escherichia coli, Shigella sp., Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Proteus sp., Bacillus cereus, Vibrio cholerae, Enterococcus faecalis, Yersinia enterocolitica, and Campylobacter jejuni can be detected and identified by our microarrays. The accuracy, range, and discrimination power of this assay can be continually improved by adding further oligonucleotides to the arrays without any significant increase of complexity or cost.

Bacteria↗

PubMed2005

Excretion and detection of SARS coronavirus and its nucleic acid from digestive system.

AIM: To study whether severe acute respiratory syndrome coronavirus (SARS-CoV) could be excreted from digestive system. METHODS: Cell culture and semi-nested RT-PCR were used to detect SARS-CoV and its RNA from 21 stool and urine samples, and a kind of electropositive filter media particles was used to concentrate the virus in 10 sewage samples from two hospitals receiving SARS patients in Beijing in China. RESULTS: It was demonstrated that there was no live SARS-CoV in all samples collected, but the RNA of SARS-CoV could be detected in seven stool samples from SARS patients with any one of the symptoms of fever, malaise, cough, or dyspnea, in 10 sewage samples before disinfection and 3 samples after disinfection from the two hospitals. The RNA could not be detected in urine and stool samples from patients recovered from SARS. CONCLUSION: Nucleic acid of SARS-CoV can be excreted through the stool of patients into sewage system, and the possibility of SARS-CoV transmitting through digestive system cannot be excluded.

Digestive System↗

PubMed2005

Preparation of immunomagnetic iron-dextran nanoparticles and application in rapid isolation of E.coli O157:H7 from foods.

AIM: To prepare a kind of magnetic iron-dextran nanoparticles that was coated with anti-E.coli O157:H7 IgG, analyze its application conditions, and try to use it to isolate E.coli O157:H7 from foods. METHODS: Magnetic iron-dextran nanoparticles were prepared by the reaction of a mixture of ferric and ferrous ions with dextran polymers under alkaline conditions. The particles were coated with antiserum against E.coli O157:H7 by the periodate oxidation-borohydride reduction procedure. The oxidation time, amount of antibody coating the particles, amount of nanoparticles, incubation time and isolation time were varied to determine their effects on recovery of the organisms. Finally, the optimum conditions for isolating E.coli O157:H7 from food samples were established. RESULTS: E.coli O157:H7 can be isolated from samples within 15 min with the sensitivity of 10(1) CFU/mL or even less. In the presence of 10(8) CFU/mL of other organisms, the sensitivity is 10(1)-10(2) CFU/mL. Nonspecific binding of other bacteria to the particles was not observed. Two and a half hours of enrichment is enough for the particles to detect the target from the food samples inoculated with 1 CFU/g. CONCLUSION: Isolation of target bacteria by immunomagnetic nanoparticles is an efficient method with high sensitivity and specificity. The technique is so simple that it can be operated in lab and field even by untrained personnel.

Escherichia coli O157↗

PubMed2005

Study on the resistance of severe acute respiratory syndrome-associated coronavirus.

In this study, the persistence of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) was observed in feces, urine and water. In addition, the inactivation of SARS-CoV in wastewater with sodium hypochlorite and chlorine dioxide was also studied. In vitro experiments demonstrated that the virus could only persist for 2 days in hospital wastewater, domestic sewage and dechlorinated tap water, while 3 days in feces, 14 days in PBS and 17 days in urine at 20 degrees C. However, at 4 degrees C, the SARS-CoV could persist for 14 days in wastewater and at least 17 days in feces or urine. SARS-CoV is more susceptible to disinfectants than Escherichia coli and f2 phage. Free chlorine was found to inactivate SARS-CoV better than chlorine dioxide. Free residue chlorine over 0.5 mg/L for chlorine or 2.19 mg/L for chlorine dioxide in wastewater ensures complete inactivation of SARS-CoV while it does not inactivate completely E. coli and f2 phage.

Chlorine↗

PubMed2005

Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital.

The transmission of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is associated with close contact to SARS patients and droplet secretions of those patients. The finding of positive RT-PCR results from stools of SARS patients suggests that stools of SARS patients or sewage containing stools of patients could transmit SARS-CoV. We used a novel style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing. We also used cell culture, RT-PCR and gene sequencing to detect and identify the viruses from sewage. No infectious SARS-CoV contamination was found in any of the samples collected, but the nucleic acid of SARS-CoV could be detected in the sewage from the two hospitals before disinfection. While the RNA was only detected in three samples from the 309th Hospital, the others were negative after disinfection. These findings provide strong evidence that SARS-CoV can be excreted through the stool/urine of patients into sewage system, thus making the sewage system a possible route of transmission.

China↗

PubMed2005

8-hydroxydeoxyguanosine as a biomarker of oxidative DNA damage induced by environmental tobacco side-stream smoke and its mechanism.

OBJECTIVE: To study the genotoxicity effect of environmental tobacco side-stream smokes (ETSS) on oxidative DNA damage and its molecular mechanism. METHODS: DNA adduct 8-hydroxydeoxyguanosine (8-OHdG) was used as a biomarker of oxidative DNA damage. The level of 8-OHdG in DNA exposed to ETSS was detected by high performance liquid chromatography with electrochemical detection. Organic and inorganic components in ETSS were analyzed by gas chromatography-mass spectrum and atomic absorption spectrum respectively. RESULTS: Particle matters (PMs) and volatile organic compounds (VOCs) in ETSS could directly induce oxidative DNA damage and formation of 8-OHdG. There were 123 and 84 kinds of organic components in PMs and VOCs respectively, and 7 kinds of inorganic components in ETSS. Some components, especially quinones and polyphenols in ETSS, could produce free radicals in vitro by auto-oxidation without any biological activity systems, and with the catalytic reaction of metals, the DNA adduct 8-OHdG was produced. CONCLUSION: ETSS have biological oxidative effect on DNA in vitro and in vivo, and expressed direct genotoxicity. 8-OHdG is a valuable biomarker of oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2005

Effects of formaldehyde inhalation on lung of rats.

OBJECTIVE: To analyze protein changes in the lung of Wistar rats exposed to gaseous formaldehyde (FA) at 32-37 mg/m3 for 4 h/day for 15 days using proteomics technique. METHODS: Lung samples were solubilized and separated by two-dimensional electrophoresis (2-DE), and gel patterns were scanned and analyzed for detection of differently expressed protein spots. These protein spots were identified by MALDI-TOF-MS and NCBInr protein database searching. RESULTS: Four proteins were altered significantly in 32-37 mg/m3 FA group, with 3 proteins up-regulated, 1 protein down-regulated. The 4 proteins were identified as aldose reductase, LIM protein, glyceraldehyde-3-phosphate dehydrogenase, and chloride intracellular channel 3. CONCLUSION: The four proteins are related to cell proliferation induced by FA and defense reaction of anti-oxidation. Proteomics is a powerful tool in research of environmental health, and has prospects in search for protein markers for disease diagnosis and monitoring.

Administration, Inhalation↗

PubMed2004

A study on detecting and identifying enteric pathogens with PCR.

OBJECTIVE: To develop a rapid and definite diagnostic test of bacterial enteritis caused by pathogenic enterobacteria, the most frequent etiologic agent of infectious enteritis in the world. METHODS: A set of conventional PCR assays were applied to detect and identify salmonella, shigella, and E. coli O157:H7 directly from pure culture and fecal samples. The general primers of pathogenic enterobacteria were located on the uidA gene, which were found not only in E. coli nuclear acid, but also in shigella and salmonella genes. Shigella primer was from ipaH gene whose coded invasive plasmid relative antigen existed both in plasmid and in genome. The primers of salmonella were designed from the 16SrRNA sequence. The primer of E. coli O157:H7 was taken from eaeA gene. Five random primers were selected for RAPD. The detection system included common PCR, semi-nested PCR and RAPD. RESULTS: This method was more sensitive, specific and efficient and its processing was rapid and simple. For example, the method could be used to specifically detect and identify salmonella, shigella, and E. coli O157:H7, and its sensitivity ranged from 3 to 50 CFU, and its detection time was 4 hours. CONCLUSION: This PCR method, therefore, can serve as a routine and practical protocol for detecting and identifying pathogenic microorganisms from clinical samples.

DNA Primers↗

PubMed2004

[Detection of RNA of SARS coronavirus in hospital sewage].

OBJECTIVE: In order to explore the existence of SARS coronavirus (Co-V) and/or its RNA in sewage of hospitals administered SARS patients. METHODS: A novel electropositive filter was used to concentrate the SARS-CoV from the sewage of two hospitals administered SARS patients in Beijing, including twelve 2,500 ml sewage samples from the hospitals before disinfection, and ten 25,000 ml samples after disinfection; as well as cell culture, RT-PCR and sequencing of gene to detect and identify the viruses from sewage. RESULTS: There was no live SARS-CoV detected in the sewage in this study. The nucleic acid of SARS-CoV had been found in the 12 sewage samples before disinfection from both hospitals by semi-nested PCR. After disinfection, SARS-CoV RNA could only be detected from the samples from the 309th Hospital, and the others were negative. CONCLUSION: It provides evidence that there is no live SARS-Cov in the sewage from hospitals with SARS patients though SARS-CoV RNA can be detected.

Hospitals↗

PubMed2002

[Attenuation of chronic stress-induced hippocampal damages following physical exercise].

The long-term potentiation (LTP) in the hippocampal dentate gyrus and the plasma glucocorticoids level were observed in rats to study the effects of physical exercise on chronic stress-induced hippocampal damages. Eight-week spontaneous wheel running exercise could attenuate the suppression of LTP induced by 21-day restraint stress, and maintain the normal plasma glucocorticoids levels. It is suggested that long-term physical exercise may protect the hippocampus from stress-induced damages.

Animals↗

PubMed2002

Detection of enteroviruses and hepatitis A virus in water by consensus primer multiplex RT-PCR.

AIM: To develop a rapid detection method of enteroviruses and Hepatitis A virus (HAV). METHODS: A one-step, single-tube consensus primers multiplex RT-PCR was developed to simultaneously detect Poliovirus, Coxsackie virus, Echovirus and HAV. A general upstream primer and a HAV primer and four different sets of primers (5 primers) specific for Poliovirus, Coxsacki evirus, Echovirus and HAV cDNA were mixed in the PCR mixture to reverse transcript and amplify the target DNA. Four distinct amplified DNA segments representing Poliovirus, Coxsackie virus, Echovirus and HAV were identified by gel electrophoresis as 589-,671-, 1084-, and 1128bp sequences, respectively. Semi-nested PCR was used to confirm the amplified products for each enterovirus and HAV. RESULTS: All four kinds of viral genome RNA were detected, and producing four bands which could be differentiated by the band size on the gel. To confirm the specificity of the multiplex PCR products, semi-nested PCR was performed. For all the four strains tested gave positive results. The detection sensitivity of multiplex PCR was similar to that of monoplex RT-PCR which was 24 PFU for Poliovrus,21 PFU for Coxsackie virus,60 PFU for Echovirus and 105 TCID(50) for HAV. The minimum amount of enteric viral RNA detected by semi-nested PCR was equivalent to 2.4 PFU for Poliovrus, 2.1 PFU for Coxsackie virus, 6.0 PFU for Echovirus and 10.5 TCID(50) for HAV. CONCLUSION: The consensus primers multiplex RT-PCR has more advantages over monoplex RT-PCR for enteric viruses detection, namely, the rapid turnaround time and cost effectiveness.

Base Sequence↗