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W T Liu

Publications and source records attributed to W T Liu.

At least 37 records · Page 2Linked to original sources
PubMed2000

Rapid diagnosis and quantification of herpes simplex virus with a green fluorescent protein reporter system.

A genetically modified cell line (Vero-ICP10-EGFP) was constructed for detection of herpes simplex virus (HSV) by a simple, rapid and direct method. The cell line was developed by stable transfection of Vero cell with a plasmid encoding the green fluorescent protein (GFP) driven by the promoter of the HSV-2 ICP10 gene. As early as 6 h after infection with HSV, fluorescence-emitting cells can be observed under a fluorescence microscope. A single infected cell emitting fluorescence can be observed with soft agar overlay by inverted fluorescence microscopy. No induction of detectable fluorescence was seen following infections with human cytomegalovirus (HCMV), varicella zoster virus (VZV), coxsackievirus A16 and enterovirus 71. Analysis by flow cytometry also demonstrated that intensity of the triggered fluorescence is proportional to the titer of HSV inoculated. Taken together, this novel GFP reporter system could become a useful means for rapid detection and quantification of HSV in clinical specimens.

Animals↗
PubMed2000

Isolation, characterization and identification of polyhydroxyalkanoate-accumulating bacteria from activated sludge.

Two novel gram-positive bacteria capable of accumulating poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(3HB-co-3HV)] were isolated from an anaerobic-oxic activated sludge system fed with acetate. Strains Lpha5 and Lpha7 are motile cocci, 1-2 microm in diameter, occurring singly or in pairs. These isolates have doubling times ranging from 0.4-1.7 d and can accumulate in high levels of poly(3HB-co-3HV) (up to 44.7% of cell dry weight) when grown on complex media. Furthermore, these two strains exhibited the rapid substrate uptake and accumulation of storage granules as observed in situ. Under aerobic conditions, about 14.4% (cell dry weight) polyhydroxyalkanoate and 82% (carbon dry weight) cellular carbohydrate were produced from acetate and glucose, respectively. Under anaerobic conditions, poly(3HB-co-3HV) and cellular carbohydrate accumulated when glucose but not acetate was fed. The result of analysis of 16S rRNA sequence revealed that both strains belong to the gram-positive high-G + C group, but are significantly different from their closest phylogenetic relatives, Dermatophilus sp. and Terrabacter sp., to warrant classification as a new species.

Journal Article↗
PubMed2000

Micropruina glycogenica gen. nov., sp. nov., a new Gram-positive glycogen-accumulating bacterium isolated from activated sludge.

A new Gram-positive non-spore-forming bacterium, strain Lg2T, was isolated from an activated sludge reactor showing enhanced biological phosphorus removal activity. The new isolate was a slowly growing organism and was capable of accumulating large amounts of intracellular glycogen from substrate taken up. Both oxidase and catalase were produced. The new isolate contained meso-diaminopimelic acid (DAP) in the cell wall. Complex fatty acid patterns with iso-C14:0, anteiso-C15:0, C16:0, iso-C16:0 and four other minor saturated or unsaturated straight-chain fatty acids were detected. The isolate contained a high genomic G+C content (70.5 mol%). Phylogenetic analysis based on the 16S rRNA gene sequence placed the isolate in the high G+C Gram-positive group with Microlunatus phosphovorus and Friedmanniella antarctica as the closest relatives (sequence similarities are 93 and 92 %, respectively). These three organisms shared common features in morphology, but strain Lg2T could be differentiated from the other species by its peptidoglycan type (meso-DAP), fatty acid composition, carbon source utilization profile and G+C content. On the basis of these findings, it is proposed that a new genus and species, Micropruina glycogenica, should be created for the new isolate; the type strain is strain Lg2T (= JCM 10248T).

Base Composition↗
PubMed2000

Using conjunctival swab with polymerase chain reaction to aid diagnosis of cytomegalovirus retinitis in AIDS patients.

Conjunctival swabs were used in combination with polymerase chain reactions (PCR) or virus culture to aid to confirm the diagnosis of cytomegalovirus (CMV) retinitis in AIDS patients. Based on ophthalmoscopic findings, 13 AIDS patients were diagnosed as having CMV retinitis and treated with systemic ganciclovir from January 1997 to December 1998. Nine of 13 AIDS patients with CMV retinitis were found to be positive for CMV DNA by using a conjunctival swab with PCR (CS-PCR). CMV was also isolated from the conjunctival swab culture in 2 AIDS patients with CMV retinitis. Following 1 month of systemic ganciclovir treatment, except for 1 patient who had disease progression and remained positive for CMV DNA by using CS-PCR, 12 patients were negative for CMV with a concordant lesion regression. Results of this study also indicate that this CS-PCR method is valuable for confirming the diagnosis of CMV retinitis and monitoring the ganciclovir effect on the treatment of CMV retinitis in AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed2000

Detection of human cytomegalovirus retinitis and monitoring of ganciclovir treatment using conjunctival swab with polymerase chain reaction in AIDS patients.

This report studies the accuracy of conjunctival swab polymerase chain reaction (CS-PCR) for the diagnosis of human cytomegalovirus retinitis (HCMV) in AIDS patients. PCR and virus culture were used for the detection of HCMV in conjunctival swab, serum, and urine specimens from 38 AIDS patients between April 1996 and April 1998. The clinical utility of the identification of HCMV retinitis by these 6 different methods was demonstrated by their prediction power to estimate AIDS patients at risk of contracting HCMV retinitis. The sensitivity, specificity, positive predictive value, and negative predictive value of CS-PCR for the detection of HCMV retinitis were 91.5%, 80.9%, 60.8%, and 92.7%, respectively; for serum PCR were 74.3%, 81.7%, 57.2%, and 90.3%; for urine PCR were 100%, 17.3%, 20.4%, and 100%; for conjunctival swab culture were 22.7%, 100%, 100%, and 86%; for serum culture were 27.3%, 98.1%, 75%, and 86.4%; and for urine culture were 90.9%, 44.2%, 25.6%, and 95.8%.

AIDS-Related Opportunistic Infections↗
PubMed2000

Ophthalmic findings in patients with acquired immunodeficiency syndrome.

Ocular manifestations have been reported in up to 60% of individuals infected with human immunodeficiency virus (HIV) in the United States, and it is becoming increasing apparent that these ocular manifestations almost invariably reflect extent of progression of the disease. The prevalence of ocular abnormalities among acquired immunodeficiency syndrome (AIDS) patients in Taiwan has not been reported. In the present study, we examined and followed up the ophthalmic conditions of a total of 274 HIV-infected patients during the period from March 1993 to May 1999. The results show that cotton-wool spots was the most common ocular finding in this series of patients with AIDS, occurring in 22 (32.8%) of 67 AIDS patients. Cytomegalovirus (CMV) retinitis was the most commonly seen opportunistic ocular infection, occurring in 14 (20.8%) of 67 AIDS patients. These findings suggest that AIDS patients should be closely followed for signs of opportunistic ocular disease which may initially be asymptomatic. Close co-operation between the ophthalmologist and the internist is essential to ensure timely therapeutic intervention, which can decrease the risk of further complications including visual impairment and blindness.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Using buffy coat for reverse transcriptase-polymerase chain reaction in the diagnosis of dengue virus infection: preliminary study.

Using reverse transcriptase-polymerase chain reaction (RT-PCR) to detect and type from viremic human serum samples for dengue virus infection is widely used today. However, a few false-negative results were reported due to very low titers of the virus particle in serum samples. As mononuclear cells, macrophages or monocytes are target cells for dengue virus infection, and the replication of virions can be observed in peripheral leukocytes frequently, the amount of virus particle in buffy coat should be higher than those in serum samples. Here, we describe a procedure in which RNA extraction from the buffy coat of a patient with a false-negative serum sample yielded specific viral RNA amplifiable by RT-PCR, thereby providing an alternative choice for the accurate diagnosis of dengue infection.

Dengue↗
PubMed1999

Anti-dsDNA autoantibody cross-reacts with the C-terminal hydrophobic cluster region containing phenylalanines in the acidic ribosomal phosphoprotein P1 to exert a cytostatic effect on the cells.

The present study was an attempt to map the epitope in P1 protein which may cross-react with anti-dsDNA. In addition to wild-type P1, the genes of its C-terminal mutants were cloned and expressed. The binding activity of these proteins with anti-dsDNA was determined by Western blot and ELISA. The P1 mutants with complete deletion of the acidic charge and hydrophobic clusters, deletion of the hydrophobic cluster, or replacement of the phenylanlanines with alanine in the hydrophobic cluster lost the binding activity. Moreover, P1 mutants with mutation at the serine phosphorylation sites (positions 102 and 105) retained their binding activities with anti-dsDNA. However, those with mutation at the serine phosphorylation sites and without the hydrophobic cluster lost their binding activities. These findings suggest that phenylalanines in the C-terminal hydrophobic cluster region of ribosomal P proteins are essential to their cross-reactivity with anti-dsDNA.

Amino Acid Sequence↗
PubMed1999

Community-based molecular epidemiology of HTLV type I in Taiwan and Kinmen: implication of the origin of the cosmopolitan subtype in northeast Asia.

To understand the possible origin and dissemination of HTLV-I infection in northeast Asia, community-based molecular epidemiological studies were conducted on the Kinmen Islands (off the coast of Fukien Province, China) and in Taiwan. A total of 3831 Taiwanese from 3 townships (Pu-Li, Chu-Dung, and Pu-Tze) and 993 aborigines from 4 tribes in Taiwan participated in this study. The prevalence rates of HTLV-I infection in adult residents from Pu-Li, Chu-Dung, and Pu-Tze were 0.82, 1.72, and 1.63%, respectively. None of the aborigines had HTLV-I infection. Previously, 0.73% of the adult population of Kin-Hu, Kinmen were found to have HTLV-I infection. Peripheral blood mononuclear cells were collected from HTLV-I carriers identified both in Taiwan and Kinmen and the HTLV-I LTR sequences were PCR amplified, subcloned, and sequenced for phylogenetic tree analysis. The results showed that all 6 HTLV-I isolates from Kinmen and 13 of 18 (72.2%) isolates from Taiwan were group a (transcontinental) of Cosmopolitan subtype, while 5 of 18 (27.8%) isolates from Taiwan were group b (Japanese) of Cosmopolitan subtype. Since all of the HTLV-I-infected persons were descendants of immigrants from mainland China, the origin of the Cosmopolitan subtype in Taiwan and Kinmen may not have been Japan, as previously theorized, but China, possibly the result of the migration of an infected population in the past several centuries.

Adult↗
PubMed1999

Genetic characterization of the hemagglutinin of two strains of influenza B virus co-circulated in Taiwan.

Two isolates of influenza B virus were obtained in the spring of 1997. One strain, B/Taiwan/21706/97, was isolated from a patient who had acute tonsillitis. The other, B/Taiwan/3143/97, was isolated from a patient who was diagnosed with meningoencephalitis. This implies that the influenza B viruses not only cause respiratory symptoms but may also cause inflammation of the nervous system. Sequence analysis of the hemagglutinin (HA) gene, HA1 domain, indicated that there were remarkable amino acid changes in the strain B/Taiwan/3143/97 compared to B/Victoria/2/87, B/Yamagata/16/88, and B/Taiwan/7/88. The changes in the positions 116, 200, 238, 242, and 271 were correlated with receptor binding. Furthermore, a potential glycosylation site at position 233 was lost. In total, 30 amino acid changes were noted at positions ranging from 116 to 295. These changes may affect the antigenicity of the virus. Phylogenetic analyses also showed that the B/Taiwan/3143/97 was located in an independent lineage, when compared to the reference strains belonging to B/Victoria/2/87 and B/Yamagata/16/88 lineages. This supports the hypothesis that influenza B viruses with distinct genetic characteristic were co-circulated in Taiwan.

Base Sequence↗
PubMed1999

Identification of a novel group of bacteria in sludge from a deteriorated biological phosphorus removal reactor.

The microbial diversity of a deteriorated biological phosphorus removal reactor was investigated by methods not requiring direct cultivation. The reactor was fed with media containing acetate and high levels of phosphate (P/C weight ratio, 8:100) but failed to completely remove phosphate in the effluent and showed very limited biological phosphorus removal activity. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA was used to investigate the bacterial diversity. Up to 11 DGGE bands representing at least 11 different sequence types were observed; DNA from the 6 most dominant of these bands was further isolated and sequenced. Comparative phylogenetic analysis of the partial 16S rRNA sequences suggested that one sequence type was affiliated with the alpha subclass of the Proteobacteria, one was associated with the Legionella group of the gamma subclass of the Proteobacteria, and the remaining four formed a novel group of the gamma subclass of the Proteobacteria with no close relationship to any previously described species. The novel group represented approximately 75% of the PCR-amplified DNA, based on the DGGE band intensities. Two oligonucleotide rRNA probes for this novel group were designed and used in a whole-cell hybridization analysis to investigate the abundance of this novel group in situ. The bacteria were coccoid and 3 to 4 microm in diameter and represented approximately 35% of the total population, suggesting a relatively close agreement with the results obtained by the PCR-based DGGE method. Further, based on electron microscopy and standard staining microscopic analysis, this novel group was able to accumulate granule inclusions, possibly consisting of polyhydroxyalkanoate, inside the cells.

Bioreactors↗
PubMed1999

Progression of cytomegalovirus retinitis in acquired immunodeficiency syndrome: a case report.

We report an AIDS patient with cytomegalovirus (CMV) retinitis that developed from an early minor lesion and progressed to extended involvement of the retina and severe deterioration of vision due to poor compliance with ganciclovir treatment. A 33-year-old man was known to have acquired immunodeficiency syndrome (AIDS) for eight months. The patient had no complaint of visual symptoms. A routine eye examination revealed his visual acuity to be 6/6 in both eyes. The dilated eye fundus examination using indirect ophthalmoscopy disclosed a localized white yellowish granular lesion in the peripheral retina of the right eye and a completely normal left eye. CMV retinitis with initial manifestation in the right eye was diagnosed. Due to incomplete treatment with ganciclovir, the retinal lesion rapidly enlarged and extended to the posterior pole, with eventual destruction of the nerve fiber layer and optic disc. The visual acuity of right eye dropped from 6/6 to 1/60 within six months. This case report indicates the importance of early, dilated eye fundus examination and recognition of early CMV retinitis in order to salvage visual function in AIDS patients. Completion of the anti-CMV treatment course in halting the progression of CMV retinitis is also emphasized.

AIDS-Related Opportunistic Infections↗
PubMed1999

Detection of IgA against Epstein-Barr virus BZLF-1 replication activator (ZEBRA) in sera of nasopharyngeal carcinoma patients with a recombinant ZEBRA protein.

BACKGROUND: Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma (NPC). An EBV-encoded immediate-early antigen, BZLF-1 replication activator (ZEBRA) initiates EBV replication and expression in all NPC tumors. In this study, we investigated whether immunoglobulin A (IgA) against ZEBRA is present in the sera of patients with NPC, and whether it was able to be determined by enzyme-linked immunosorbent assay (ELISA) using a recombinant ZEBRA prepared from Escherichia coli. METHODS: A polymerase chain reaction-amplified cDNA fragment of the ZEBRA gene was inserted into the expression vector of E coli under the control of an IpL promoter. E coli bacteria containing the CI857 gene served as host to overexpress the ZEBRA protein by heat induction. Recombinant ZEBRA was collected by mechanical disruption of the bacteria, purified by column chromatography, and analyzed by SDS-PAGE and Western blot assay using sera from NPC patients. The recombinant ZEBRA was used to develop the ELISA to detect IgA against ZEBRA. RESULTS: The amount of ZEBRA produced comprised 30% of total E coli protein. Western blot assay confirmed that affinity of the recombinant ZEBRA to IgA antibody was preserved. IgA against ZEBRA was shown to be positive by ELISA in 36 of 40 NPC sera, but in only nine of 55 patients with other head and neck malignancies, and two of 35 normal individuals. For serologic diagnosis of NPC, the sensitivity of IgA/ZEBRA detected by ELISA was 90% and the specificity was 87.4%. CONCLUSIONS: A recombinant ZEBRA was produced at high levels in E coli and retained affinity to IgA against ZEBRA. The recombinant ZEBRA was successfully used to develop an ELISA for the detection of IgA against ZEBRA. The high sensitivity and specificity of IgA against ZEBRA show that the ELISA is feasible for serologic diagnosis of NPC.

Adult↗
PubMed1998

Self-perceived health and 5-year mortality risks among the elderly in Shanghai, China.

Studies of the elderly worldwide over the last 3 decades have reported that a self-rating of "poor" compared with "excellent/good" health increases the relative risk of dying. The authors tested the strength of this association by performing age-stratified Cox regression analyses on a 5-year longitudinal study of a representative sample of noninstitutionalized elderly aged 65 years and older (n=3,094) in a district of Shanghai, China. More than 20 potential confounders that were only partially controlled in other studies and threats to response validity due to cognitive impairment or diagnosed dementia that were not considered in previous studies were taken into account in this analysis. The results showed that among those aged 65-74 years, "poor" perceived health increases the adjusted relative risk of death by 1.93 (95% confidence interval 1.20-3.11) compared with "excellent/good" health. The adjusted relative risk of a "fair" rating of health is 2.16 (95% confidence interval 1.44-3.25). In the older age group, mortality risks for the ratings of fair as well as poor compared with excellent/good health were not statistically significant. The authors posit that several mechanisms related to host vulnerability markers and greater-than-expected utilization of health services may explain the association between self-assessed health and mortality risks. Future research should strive to develop more precise measures of these and related variables.

Aged↗
PubMed1998

Structural characterization of two novel oxidative derivatives of cyclosporine generated by a chemical method.

OBJECTIVES: To study the generation of cyclosporine derivatives (CMs) by chemical oxidation of the parent compound using hydrogen peroxide. METHODS AND RESULTS: Hydrogen peroxide was added to cyclosporine (CsA), which was dissolved in ether. After liquid-liquid extraction, CMs were purified by high performance liquid chromatography (HPLC). Detailed structures of CMs were determined by fast atomic bombardment mass spectrometry (FABMS) and nuclear magnetic resonance spectroscopy (NMR). Our results indicated that the parent compound was modified at amino acid number 1 by hydroxylation of the carbon and the formation of a tetrahydrofuran five member ring structure. In addition, these two oxidative products of CsA were determined to be isomeric to each other, differing only in the configuration at one or more carbon atoms. This modification is in contrast to that observed for the formation of the cyclic metabolite of CsA, namely AM1c, by cytochrome P-450 isoenzymes, where the addition of the hydroxyl group occurs on the carbon of amino acid 1. CONCLUSION: 3 to 4 mg of 2 oxidative derivatives could be produced from 5 mg of CsA by chemical modification of the parent compound. In comparison, biotransformation using the drug-induced hepatic microsomal enzyme system could only produce 0.5 to 1 mg of metabolites/derivatives from 5 mg of CsA.

Chromatography, High Pressure Liquid↗
PubMed1998

Coxsackievirus B1 infection in infants less than 2 months of age.

Most of the neonatal enteroviral infections reported in the literature are associated with Coxsackievirus B2-B5 and echovirus 9 and 11. We report a retrospective Coxsackievirus B1 (CB1) infection in infants less than 2 months of age. Seventeen patients had aseptic meningitis and 8 had systemic sepsis (multi-organ involvement including meningitis, impaired liver function, and abnormality in coagulation). The symptoms and signs were nonspecific and could not be distinguished with bacterial infection on clinical grounds. Virus isolation was mandatory for diagnosis. Impaired liver function and coagulation profiles were noted in patients with systemic sepsis, but not in patients with meningitis only. CSF examination showed some uncommon features of viral meningitis: predominance of polymorphonuclear cells (PMN) was noted in 62.5% of patients and hypoglycorrhachia in 64% of patients. The patients with only meningitis recovered completely without any sequela. One of the eight patients with systemic sepsis died with case fatality rate 12.5%. Physicians should be aware of the possibility of CB1 virus infection in young infants during prevalent seasons. Specimens should be sent for viral culture in patients with meningitis and sepsis to make a definite diagnosis.

Age of Onset↗