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Biomedical subjects

L Wen

Publications and source records attributed to L Wen.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Clinical and experimental study on antiviral activity of reduqing against human cytomegalovirus].

OBJECTIVE: To investigate the therapeutic efficacy of traditional Chinese medicine Reduqing (RDQ) against human cytomegalovirus (HCMV) in clinical and its antiviral activity in vitro. METHODS: In clinical practice, HCMV antibody was detected to determine if the case was activity infected with HCMV. Fourteen patients were found and treated with RDQ. The drug was orally administered one dose, three times a day, for 18-30 days as one therapeutic course. And the efficacy was evaluated by ELISA, PCR and other methods. The in vitro inhibitory activity of RDQ against HCMV AD169 was carried out on human embryo lung fibroblasts (HEL) by cytopathic effect inhibition method. Ganciclovir (GCV) was used for positive control. RESULTS: Fourteen pre- or during pregnant women with HCMV infection were treated with RDQ. After 18-30 days of treatment, all of them showed HCMV-IgM negative conversion, HCMV DNA negative conversion in 7/10 cases, and virus excretion by urine and cervix secretion was inhibited in 4/4 and 1/1 case. Five women gave birth to 5 normal newborns at term after treatment, among them 2 were asymptomatic virus carrier, the other 3 were uninfected. Experimental study in vitro showed that the maximal tolerance dosage (TD0) of RDQ was 20 micrograms/L, the minimal therapeutic concentration (MTC) was 5 micrograms/L, 50% inhibitory concentration (IC50) was 5 micrograms/L and the therapeutic index (TI) was 4. It suggested that RDQ had anti-HCMV activity in vitro and the effect increased with its concentration. CONCLUSION: RDQ is a safe, valuable drug for inhibiting HCMV infection especially during pregnancy.

Adult↗
PubMed2000

[Experimental research on inhibitory effect of alcohol extracts from Loranthus yadoriki Sieb. on coxsackie B3 virus].

OBJECTIVE: To investigate the antiviral effect of two components (B and C) in the alcohol extracts from Loranthus yadoriki Sieb for development of new antiviral drugs for coxsackie B3 virus(CVB3). METHOD: Using ribavirin as positive control, the plaque reduction assay was adopted for pharmadynamic detection. RESULTS: In the HEp-2 cell system, with respect to direct virucidal activity and the inhibition on CVB3 infection and multiplication, ED50s of component B were 2.32 micrograms.ml-1, 0.24 microgram.ml-1 and 1.91 micrograms.ml-1, respectively and those of component C, 1.44 micrograms.ml-1, 2.06 micrograms.ml-1 and 3.70 micrograms.ml-1 respectively. For the inhibition on multiplication of CVB3, ED50 of ribavirin was 7.55 micrograms.ml-1. CONCLUSION: Treatment indexes (TI) of the direct virucidal activity and inhibitory effects of component B on CVB3 infection and multiplication 22.6, 219 and 27.5 respectively; component C, 115, 165 and 21.6; inhibition of ribavirin on CVB3 is 38, which is comparable to those of components B and C. It is thus suggested that the anti-CVB3 action of components B and C in the alcohol extracts from Loranthus yadoriki Sieb deserves to be exploited.

Antiviral Agents↗
PubMed2000

[Determining the distribution of Mutans Streptococci in human dental plaque by monoclonal antibody against SA I/II and SPAa of Mutans Streptococci].

OBJECTIVE: To explore the possibility of detecting the distribution of Mutans Streptococci in human dental plaque by Monoclonal antibody (WC2E10c, WC3A6d) against SA I/II and SPAa of Mutans Streptococci, which was prepared in our lab. METHODS: 60 subjects were divided into the experimental group and the control group. The distributions of Mutans Streptococci (serotype c and d) in dental plaques were detected in 60 subjects by the clonal blot technique. Positive colonies were examined by bacterial morphology, serology, biochemistry and SDS-PAGE. RESULTS: Bacterial colony was significantly different between the experimental group and the control group with eye observation. Colonies of the experimental group were deep brown and easily differentiated, but colonies of control group were white. Brown colonies were proved to be Mutans Streptococci (serotype c and d) by using assay of bacterial morphology, serology, biochemistry and SDS-PAGE, but white colonies were not. CONCLUSION: McAbs (WC2E10c, WC3A6d) were shown high specificity in Mutans Streptococci (Serotype c and d) of human dental plaques.

Adolescent↗
PubMed2000

[Detection of bacterial DNA in blood with three pairs of primers].

OBJECTIVE: To develop a stable and sensitive method to detect gut-derived bacterial DNA present in the blood. METHODS: Blood culture and PCR were performed simultaneously when temperature of patients (n = 23) was higher than 38.5 degrees C after laparotomy. PCR was performed after DNA extraction, target genes being beta-lactosidase gene of Escherichia coli(E. coli), glutamine synthase gene of Bacteroides Fragilitas, and 16SrRNA gene of most pathogenic bacteria. DNA of standard strains of E. coli and Bacteroides Fragilitas served as positive controls, blank control as negative controls, and healthy volunteers (n = 20) served as normal controls. We performed PCR twice with part of the samples (n = 20) in order to test the repetition of this method. RESULTS: The repetition rate of PCR was 95%. Three of blood cultures were positive (13.0%, 3/23), the corresponding positive ratio of PCR was 43.5% (10/23) which was higher than that of the blood culture (P = 0.016). CONCLUSION: PCR is more sensitive than blood culture in detection of bacteremia.

Bacterial Translocation↗
PubMed1999

[Cloning and expression of bluetongue virus VP3 protein in insect cells].

OBJECTIVE: To elucidate the biological activities of VP3 protein of bluetongue virus (BTV) expressed in insect cells and to assemble, in future, the BTV core-like particles. METHODS: First, full length of BTV13 L3 cDNA was constructed from 2 sequenced clones. The silver staining of the splicing region proved that the construction was correct. Then, a recombinant baculovirus expression vector pFB1BL3 was constructed to express the L3 gene in insect cells. RESULTS: BTV13 VP3 could be highly expressed in Sf-9 cells, the production could occupy up to 10%-15% of the total cell protein. Core-like particles could be observed after co-expression of the VP3 and VP7 in insect cells. CONCLUSION: VP3 of BTV expressed in insect cells possesses biological activity and can be used to assemble BTV core-like particles.

Animals↗
PubMed1999

Transcription repression by Xenopus ET and its human ortholog TBX3, a gene involved in ulnar-mammary syndrome.

T box (Tbx) genes are a family of developmental regulators with more than 20 members recently identified in invertebrates and vertebrates. Mutations in Tbx genes have been found to cause several human diseases. Our understanding of functional mechanisms of Tbx products has come mainly from the prototypical T/Brachyury, which is a transcription activator. We previously discovered ET, a Tbx gene expressed in Xenopus embryos. We report here that ET is an ortholog of the human Tbx3 and that ET is a repressor of basal and activated transcription. Functional dissection of the ET protein reveals a novel transcription-repression domain highly conserved among ET, human TBX3, and TBX2. These results reveal a new transcription repressor domain, show the existence of a subfamily of transcription repressors in the Tbx superfamily, and provide a basis for understanding etiology of diseases caused by Tbx3 mutations.

Amino Acid Sequence↗
PubMed1999

[Cloning of 0-17.5 mu and sequencing of 0-4.8 mu of the lefe and DNA of the Ad7 vaccine strain left end].

OBJECTIVE: Cloning of 0-17.5 mu DNA fragment of adenovirus 7 vaccine strain and sequencing of 0-4.8 mu fragment (1,737 bp). METHODS: Isolating and purifying Ad7 vaccine genome from the A549 cultured cells, putting 0.3-17.5 mu fragment into pAd7T plasmid, then sequencing the 0-4.8 mu fragment including inverted terminal repeats (ITR), packaging sequence and Ela region. RESULTS: We obtained 0-17.5 mu fragment of Ad7 vaccine strain genome and sequenced its left terminal 1,737 bp. Sequence analysis showed that the Ad7 vaccine strain Ela region encodes 6,300, 24,000 and 28,000 proteins. Compared with equivalent region of Ad7 Gomen strain, they share the homology of the nucleotide sequence 98.9%, 97.3%, 97.5% and the homology of the deduced amino acid sequence 96.6%, 96.5%, and 96.9% respectively. When compared with Ad7 Grider strain, they share the homology of the nucleotide sequence 100%, 99.7%, 99.7% and the homology of the deduced amino acid sequence 100%, 99.1%, and 99.2% respectively. CONCLUSION: The Ad7 vaccine strain left terminal 1,737 bp nucleotide sequence showed a high homology with corresponding region of Ad7 Gomen strain and Grider strain.

Adenoviridae↗
PubMed1999

[The experimental and clinical study of inhibitory effects of Re-Du-Qing on human cytomegalovirus (HCMV)].

OBJECTIVE: To study the theurapeutic effect of Chinese medicine Re-Du-Qing on HCMV. METHODS: The expression of the HCMV late-mRNA in infected cells was measured by quantitative RT-PCR and the development of cytopathic effect (CPE) caused by HCMV was observed before and after the treatment of Chinese medicine "Re-Du-Qing". On the basis of its anti-HCMV activity study in vitro, Re-Du-Qing was applied to the child-bearing aged women and to pregnant women who were HCMV-IgM positive which indicated the active HCMV infection, meanwhile the serum levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) were measured before and after the treatment by the ELISA method. RESULTS: The results showed that the Re-Du-Qing had strong inhibition effect both on HCMV-mRNA and CPE. The serum level of the TNF-alpha increased and IL-2 decreased significantly in HCMV-IgM positive cases when compared with normal women. After being treated with Re-Du-Qing, the serum TNF-alpha and IL-2 in patients returned to normal level, and 72.9% of the HCMV-IgM positive cases turned negative which was significantly higher than that (13.6%) in control group. CONCLUSION: It was suggested that serum TNF-alpha level is closely related to the activity of HCMV which has harmful effect on immune system. Re-Du-Qing can enhance immunity of the body and has an obvious inhibition on HCMV in Vitro and Vivo, and can thus serve as safe and effective medicine for treatment of active HCMV infection, especially for the pregnant women.

Adult↗
PubMed1999

Pleiotropic effects of a nuclear restorer-of-fertility locus on mitochondrial transcripts in male-fertile and S male-sterile maize.

Cytoplasmic male sterility (CMS) is encoded by the plant mitochondrial genome and can be reversed by nuclear restorer-of-fertility(Rf) alleles. In the CMS-S system of maize, reproductive failure and fertility restoration are gametophytic, occurring during the starch-filling stages of pollen development. Transcripts of the CMS-S-associated mitochondrial open reading frames (orf355 and orf77) are present from the early stages of microspore development through the aborted pollen stage. To investigate the molecular basis of fertility restoration, we compared mitochondrial-transcript accumulation in aborting CMS-S pollen and in CMS-S pollen restored to fertility by the Rf3 nuclear allele. In the presence of the Rf3 allele, novel, shorter transcripts of the orf355-orf77, cob and atp6 mitochondrial genes were created, and the relative abundance of larger transcripts was decreased for each of these loci. The altered transcript patterns cosegregated with male fertility conditioned by the Rf3 allele. The novel cob and atp6 transcripts were also observed in leaf-tissues of both normal and S-cytoplasm plants carrying the Rf3 allele. These observations support the hypothesis that the Rf3 allele encodes, or regulates, a modifier of mitochondrial transcript (Mmt) activity that affects both CMS and essential mitochondrial gene transcripts.

Alleles↗
PubMed1999

Characterization of sinapyl derivatives in pineapple (Ananas comosus [L.] Merill) juice.

Three previously unidentified phenolic compounds were found in pineapple (Ananas comosus [L.] Merill) juice in substantial concentrations and were isolated by semipreparative reverse phase HPLC. The structures were elucidated from UV spectra, acid hydrolysis, and subsequent amino acid analysis, mass spectrometry, and two-dimensional NMR spectroscopy. The compounds are identified as S-sinapyl-L-cysteine, N-L-gamma-glutamyl-S-sinapyl-L-cysteine, and S-sinapylglutathione.

Beverages↗
PubMed1999

Chemical modification of xylanase from Trichosporon cutaneum shows the presence of carboxyl groups and cysteine residues essential for enzyme activity.

The endo-beta-1,4-xylanase (EC 3.2.1.8) from Trichosporon cutaneum was chemically modified using amino acid-specific reagents. The enzyme does not bear arginines essential for activity, since 1,2-cyclohexanedione and 2,3-butanedione, although they modify the enzyme (after chromatographic analysis), have no effect on its activity. Reaction of the enzyme with tetranitromethane and N-acetylimidazole did not result in a significant activity loss as a result of modification of tyrosine residues. The water-soluble carbodiimide 1-[3-(dimethylamino) propyl]-3-ethylcarbodiimide inactivated the xylanase rapidly and completely in a pseudo-first-order process, and kinetic analysis indicated that at least one molecule of carbodiimide binds to the enzyme for inactivation. A mixture of neutral xylooligomers provided significant protection of the enzyme against this carbodiimide inactivation. Reaction of the xylanase with 2,4,6-trinitrobenzene sulfonic acid did not result in a significant activity loss as a result of modification of lysine residues. Titration of the enzyme with 5,5'-dithiobis-(2-nitrobenzoic acid) and treatment with iodoacetamide and p-chloromercuribenzoate indicated the presence of a free/active thiol group. Xylan completely protected the enzyme from inactivation by p-hydroxymercuribenzoate, suggesting the presence of cysteine at the substrate-binding site. Inactivation of xylanase by p-hydroxymercuribenzoate could be restored by cysteine.

Amino Acids↗
PubMed1999

Identification of an MHC class I-restricted autoantigen in type 1 diabetes by screening an organ-specific cDNA library.

Type 1 diabetes is an autoimmune disease in which the insulin-producing pancreatic beta cells are destroyed at an early age by an immune process that involves both CD4 and CD8 T lymphocytes. The identification of autoantigens in diabetes is very important for the design of antigen-specific immunotherapy. By screening a pancreatic islet cDNA library, we have identified the autoantigen recognized by highly pathogenic CD8 T cells in the non-obese diabetic mouse, one of the best animal models for human diabetes. This is the first identification, to our knowledge, of a CD8 T-cell epitope in an autoimmune disease. The peptide recognized by the cells is in the same region of the insulin B chain as the epitope recognized by previously isolated pathogenic CD4 T cells. This has very important implications for the potential use of insulin in preventative therapy.

Amino Acid Sequence↗
PubMed1999

[Diagnostic value of human cytomegalovirus late-mRNA detection for intrauterine active human cytomegalovirus infection].

OBJECTIVE: To study diagnostic value of late-mRNA detection for intrauterine active human cytomegalovirus (HCMV) infection. METHODS: The HCMV late-mRNA in peripheral blood of the pregnant women with HCMV-IgM positive and their fetal appendages (such as chorionic villi, amniotic fluid, umbilical blood and placenta) were detected by reverse transcription polymerase chain reaction(RT-PCR). RESULTS: The late-mRNA was detected in 23 out of 42 HCMV-IgM positive pregnant cases, with the 54.3% of corresponding rate between the results of HCMV-IgM and HCMV late-mRNA. 7 samples out of 13 fetal appendages from m-RNA positive mothers were late-mRNA positive, while in 12 mothers with late-mRNA negative group only one fetal sample was late-mRNA positive, Between two groups there was significant difference in mother-fetus transmission rate. CONCLUSIONS: The positive result of HCMV-IgM can not accurately reflect HCMV activity at the time being detected, which is closely related to the mother-fetus transmission rate. As a symbol of active HCMV infection, late-mRNA can not only reflect the mother-fetus transmission rate during active HCMV infection correctly, but also provide some information about activity of the HCMV in fetal tissue, It also has a great value in prediction for prognosis of infectious fetuses.

Cytomegalovirus↗
PubMed1999

[A novel alternative splicing mode of the erythropoietin receptor gene in rats].

OBJECTIVE: To detect new alternative splicing mode of erythropoietin receptor (EpoR) gene in normal rats. METHODS: Total RNAs were isolated from bone marrow mononuclear cells of normal Wistar rats. Reverse transcriptase polymerase chain reaction (RT-PCR) of the total RNAs was done and the amplified products were sequenced. RESULTS: After RT-PCR with a pair of primers (sense: 637/657 bp, and antisence: 903/882 bp), two bands were detected, the expected band (267 bp) and a longer one (346 bp) which had a 79 bp insert between 736th and 737th bases from the first ATG of the rat EpoR nucleotide. Sequence analysis showed that the 79 bp insert was the retaining intron 5 with a C-to-T point mutation at 16th base and an insertion of G base between 49th and 50th base. The insertion of G base caused a shift in reading frame and resulted EpoR with a truncated intracellular domain. CONCLUSION: A new alternative splicing of EpoR mRNA encoding truncated intracellular domain was identified in normal Wistar rats. Its implication in rat erythropoiesis remains to be determined.

Alternative Splicing↗
PubMed1999

[The PCNA immunohistochemical study of pterygium].

OBJECTIVE: To study the proliferating status of pterygium and the drug's influence on it. METHOD: Fifty four patients with pterygium were randomly assigned into three groups: Before the surgical excision of the pterygium, group 1 (18 cases) had received no drug, group 2 (16 cases) received local dexamethasone treatment, and group 3 (20 cases), local homoharringtonine and dexamethasone treatment. The immunohistochemical study on proliferating cell nuclear antigen (PCNA) was performed on the surgical specimens of the pterygium. RESULT: The PCNA positive rate was (11.53 +/- 3.62)% in the untreated group, (10.28 +/- 4.18)% in the dexamethasone group (P > 0.05), and (5.59 +/- 3.82)% in the homoharringtonine and dexamethasone group (P < 0.01). The PCNA positive rate was higher in the younger patients (< 60 years) with progressive type of the disease than that in the elder patients (>or= 60 years) with quiet type. CONCLUSIONS: There are cell proliferation and PCNA expression in pterygium. The homoharringtonine and dexamethasone local injection before the excision of pterygium can effectively decrease the PCNA expression and recurrence rate of pterygium. Local injection of dexamethasone before surgical excision has no influence on the PCNA expression of pterygium.

Adult↗
PubMed1999

[Cloning and sequencing of variable region gene of heavy chain of monoclonal antibody against SA I/II of Streptococcus mutans].

OBJECTIVE: To clone and sequence a immunoglobulin variable region of heavy chain (VH) from a mouse hybridoma 2B12F6, which produce monoclonal antibody against SA I/II of Streptococcus mutans. METHODS: The immunoglobulin variable region gene of heavy chain of 2B12F6 was amplified and cloned into pUC18 by using PCR technique and gene engineering technique, and then the gene sequence was analyzed by Sanger's method. RESULTS: The VH gene segment was 360 base pairs in length and coded 118 amino acids, and the homology of framework of VH gene and mouse VH gene published was 70%, which accorded with the feature of mouse VH gene. CONCLUSION: The VH gene gained from 2B12F6 could provide the possibility of construction of gene engineering antibody against SA I/II of Streptococcus mutans.

Amino Acid Sequence↗
PubMed1999

[Expression, purification and bio-activity analysis of oncostatin in GST-fusion expression system].

Oncostatin (OSM) is an important cytokine which has diverse biological activities. It may be useful in basic scientific and clinical studies. OSM was efficiently expressed by cloning the OSM gene into GST fusion expression vector. The level of expression of the fusion protein was about 50% of the total cell protein by SDS-PAGE analysis. The percentage of fusion protein in soluble protein could be 15% when the induction was in low temperature. The purity of purified GST-OSM with an affinity chromatography column was about 90% after the inclusion bodies had denatured and renatured. The result of activity study showed that the first two amino acids in N-terminal of the OSM were important to the biological activity of OSM.

Chromatography, Affinity↗