Biomedical subjects

Jie Wen

Publications and source records attributed to Jie Wen.

At least 37 records · Page 2Linked to original sources

PubMed2005

[Genetic parameter estimation for inosine-5-monophosphate and intramuscular fat contents and other meat quality traits in chicken muscle].

The genetic parameters for some important flavor traits like inosine-5'-monophosphate (IMP) and intramuscular fat (IMF) contents in breast meat were estimated using a MTDFREML procedure on 1063 male, 90-day-old, purebred Beijing-You meat-type chicks (BJY). The result showed that the heritability of IMP and IMF contents in BJY breast meat was moderate or low (h2=0.23, 0.10), whereas these parameters were higher for abdominal fat weight (AFW), breast meat yield (BMY), ratio of BMY to carcass weight (BMR), leg muscle yield (LMY), body weight (BW), comb weight(CW) and comb weight percentage (CWB) (h2=0.56-0.79). The heritability of abdominal fat percentage (AFP), leg meat yield (LMY), testicle weight (TW) and testicle weight percentage (TWP) were 0.24, 0.32, 0.39 and 0.35, respectively. IMP exhibited low phenotypic correlations with BMY, LMY and SFT and no significant phenotypic correlations with other traits. IMF, to some extent, exhibited positive phenotypic correlation with BW, AFP, SFT and FSW (rP=0.11-0.33). In terms of genetic correlation, IMP was moderately or significantly negatively correlated with BW and CWP (rA=-0.38,-0.62), and a high level of positive correlation was observed with BMY (rA=0.57). Moreover, IMF was highly correlated with BW and AFW (rA=0.75,0.66), and moderately correlated with AFP and CWP (rA=0.32, 0.40). A low level of positive correlation was observed between IMP and IMF (rA =0.27). We propose that IMP and IMF contents in chicken meat could be increased with selection through line-breeding.

Abdominal Fat↗

PubMed2005

[Study on pharmacodynamics of run chang tong bian granules].

OBJECTIVE: To study the effect of Run Chang Tong Bian Granules (RCTBG) on stomach and intestine peristalsis in mice and rabbits. METHODS: We conducted the intestine peristalsis test and gastric emptying test to observe the purgative action of RCTBG and the effect on isolated intestine of rabbits. RESULTS: RCTBG could effectively expedite the advance speed of charcoal powder in the small intestine and improve the velocity of intestine. It could also reduce the residual rate of methyl orange in stomach and improve the velocity of gastric emptying. RCTBG could remarkably shorten the time of defecation, increase excrement quantity of mice, excite the isolated intestine of rabbits and increase its tension and contraction amplitude. CONCLUSION: RCTBG has remarkable effect on catharsis.

Animals↗

PubMed2004

SATB1 family protein expressed during early erythroid differentiation modifies globin gene expression.

Special AT-rich binding protein 1 (SATB1) nuclear protein, expressed predominantly in T cells, regulates genes through targeting chromatin remodeling during T-cell maturation. Here we show SATB1 family protein induction during early human adult erythroid progenitor cell differentiation concomitant with epsilon-globin expression. Erythroid differentiation of human erythroleukemia K562 cells by hemin simultaneously increases gamma-globin and down-regulates SATB1 family protein and epsilon-globin gene expression. Chromatin immunoprecipitation using anti-SATB1 anti-body shows selective binding in vivo in the beta-globin cluster to the hypersensitive site 2 (HS2) in the locus control region (LCR) and to the epsilon-globin promoter. SATB1 overexpression increases epsilon-globin and decreases gamma-globin gene expression accompanied by histone hyperacetylation and hypomethylation in chromatin from the epsilon-globin promoter and HS2, and histone hypoacetylation and hypermethylation associated with the gamma-globin promoter. In K562 cells SATB1 family protein forms a complex with CREB-binding protein (CBP) important in transcriptional activation. In cotransfection experiments, increase in epsilon-promoter activity by SATB1 was amplified by CBP and blocked by E1A, a CBP inhibitor. Our results suggest that SATB1 can up-regulate the epsilon-globin gene by interaction with specific sites in the beta-globin cluster and imply that SATB1 family protein expressed in the erythroid progenitor cells may have a role in globin gene expression during early erythroid differentiation.

Cell Differentiation↗

PubMed2004

[Dynamic changes of immunoglobulin G in convalescents who have suffered from severe acute respiratory syndrome patients].

OBJECTIVE: To investigate the dynamic changes of the antibody specific to severe acute respiratory syndrome (SARS) coronavirus in convalescents who have suffered from SARS. METHODS: Samples of peripheral blood were collected twice during the first 2 weeks after discharge and then once every 2 - 4 weeks from 310 convalescents of SARS, 131 males and 179 females, aged 18 - 74, discharged from hospitals in Beijing April 3 to June 20 2003 with the average discharge date of June 10, to detect the level of immunoglobulin G (IgG) by ELISA. A curve of level of IgG was drawn to describe the change by the specific month in the year. RESULTS: Most of the 310 convalescents underwent successive or non-successive testing for 2 - 4 months and 15 were tested for 5 months, 15 for 6 months, and 2 for 7 months. IgG was detected in each sample with the mean of A value of 0.97 +/- 0.37 (0.197 - 1.849). The mean IgG level peaked in July (1.203), about 35 days after discharge, and then gradually declined to 0.857 in December, a decline by 27.3%. CONCLUSION: All SARS patients generate specific antibody against the coronavirus. However, the antibody level gradually decline with the lapse of time during the convalescence. Long-term surveillance of the change of antibody is necessary.

Adolescent↗

PubMed2004

Biodegradable polyphosphoester micelles for gene delivery.

A new biodegradable polyphosphoester, poly[[(cholesteryl oxocarbonylamido ethyl) methyl bis(ethylene) ammonium iodide] ethyl phosphate] (PCEP) was synthesized and investigated for gene delivery. Carrying a positive charge in its backbone and a lipophilic cholesterol structure in the side chain, PCEP self-assembled into micelles in aqueous buffer at room temperature with an average size of 60-100 nm. It could bind and protect plasmid DNA from nuclease digestion. Cell proliferation assay indicated a lower cytotoxicity for PCEP than for poly-L-lysine and Lipofectamine. The IC50 determined by the WST-1 assay was 69.8, 51.6, and 12.1 microg/mL for PCEP, Lipofectamine, and poly-L-lysine, respectively. PCEP efficiently delivered DNA to several cell lines such as HEK293, Caco-2, and HeLa. The highest efficiency was achieved when PCEP/DNA complex was prepared in Opti-MEM with a +/- charge ratio of 1.5-2. The transfection efficiency did not change significantly when the complex was used 3 days after preparation. The addition of chloroquine to the formulation increased transfection efficiency 10- to 50-fold compared to the complex alone. In vivo studies showed a luciferase expression by PCEP/DNA complexes in muscle increasing with time during 3 months, although the expression level was lower than that by direct injection of naked DNA. In addition to biodegradability and lower toxicity, the PCEP micelle carrier offers structural versatility. The backbone charge density and the side chain lipophilicity are two parameters that can be varied through copolymerization and monomer variation to optimize the transfection efficiency.

Biocompatible Materials↗

PubMed2004

Real-time quantitative fluorescent reverse transcriptase-PCR for detection of severe acute respiratory syndrome-associated coronavirus RNA.

AIM: SARS-associated coronavirus (SARS-CoV) has been confirmed as the pathogen for severe acute respiratory syndrome (SARS). The aim of our study was to construct a sensitive and specific real-time quantitative fluorescent (QF) reverse transcriptase (RT)-PCR method for the detection of SARS-CoV RNA. METHODS: Stored blood specimens from 44 patients with confirmed SARS were used along with blood samples from two sets of controls, 30 healthy volunteers who had no contact with SARS patients, and 30 healthy doctors and nurses who had contact with SARS patients but were without symptoms of SARS. Two pairs of primers were synthesized by the Shanghai Sangon Company according to SARS-CoV BJ01 strain sequence (AY278488), and then a pair of primers were designed and compared with a pair of primers published by WHO. RESULTS: Using serial dilutions of SARS-CoV, the 44 blood samples from SARS patients specimens were tested. Using a 0.01% dilution of SARS-CoV, all 44 clinical samples tested positive in our assay. In comparison, using a 0.1% dilution of SARS-CoV, 26 of the 44 samples tested positive using the WHO primers. In the QF-RT-PCR assay, there was a linear amplification from 100 copies to 10(8) copies of the control RNA per RT-PCR and at least 10 copies, and sometimes even 1 copy, of target RNA tested positive in our assay. CONCLUSION: The primer we developed is sufficiently sensitive and specific to diagnose symptomatic SARS-CoV infections and for monitoring virus load.

Case-Control Studies↗

PubMed2004

The effect of the degree of chitosan deacetylation on the efficiency of gene transfection.

Chitosans with various degrees of deacetylation were synthesized by acetylation with acetic anhydride. These chitosans were evaluated for efficacy of nanoparticle formation, DNA binding efficiency, morphology, and in vitro and in vivo gene transfection efficiency. DNA binding efficacy was reduced as degree of deacetylation was decreased, therefore requiring an increased +/-ratio to effect complete DNA complexation. For chitosan with a molecular weight of 390 kDa, the +/-ratio to achieve complete DNA complexation for degrees of deacetylation of 90%, 70% and 62% was 3.3:1, 5.0:1, and 9.0:1, respectively. The size and morphology of these nanoparticle formulations were not significantly different. The decreased degree of deacetylation results in a decrease in overall luciferase expression levels in HEK293, HeLa, and SW756 cells due to particle destabilization in the presence of serum proteins. However, intramuscular luciferase expression levels increased with decreasing deacetylation over the time points tested. Degree of chitosan deacetylation is an important factor in chitosan-DNA nanoparticle formulation as it affects DNA binding, release and gene transfection efficiency in vitro and in vivo.

Cell Line↗

PubMed2004

Antibody response and viraemia during the course of severe acute respiratory syndrome (SARS)-associated coronavirus infection.

To understand the time-course of viraemia and antibody responses to severe acute respiratory syndrome-associated coronavirus (SARS-CoV), RT-PCR and ELISA were used to assay 376 blood samples from 135 SARS patients at various stages of the illness, including samples from patients who were in their early convalescent phase. The results showed that IgM antibodies decreased and became undetectable 11 weeks into the recovery phase. IgG antibodies, however, remained detectable for a period beyond 11 weeks and were found in 100 % of patients in the early convalescent phase. SARS-CoV viraemia mainly appeared 1 week after the onset of illness and then decreased over a period of 1 month, becoming undetectable in the blood samples of the convalescent patients. At the peak of viraemia, viral RNA was detectable in 75 % of blood samples from patients who were clinically diagnosed with SARS 1 or 2 weeks before the test.

Adolescent↗

PubMed2003

Poly(D,L-lactide-co-ethyl ethylene phosphate)s as new drug carriers.

Many biodegradable polymers have been developed for controlled drug delivery. The plethora of drug therapies and types of drugs demand different formulations, fabrications conditions and release kinetics. No one single polymer can satisfy all the requirements. To extend the properties of poly(D,L-lactide) (PLA), we synthesized copolymers of PLA and poly(ethylethylene phosphate) (PEEP) by ring-opening polymerization using Al(Oipr)3 as the initiator. The copolymers were structurally characterized by IR and 1H NMR. DSC data confirmed the formation of random microphase structure in all the copolymers, and showed a decrease of Tg from 43.2 to -22.6 degrees C when the molar content of ethylethylene phosphate (EEP) increased from 5 to 40%. The hydrophilicity of the copolymers increased with EEP content. In contrast to the degradation behavior of PLA, disc samples made of PLAEEP90 showed a linear weight loss profile in PBS (pH 7.4) at 37 degrees C. BSA microspheres using PLAEEP90 were prepared by double-emulsion method, yielding a loading level of 4.3% and a loading efficiency of 75%. The BSA release profile consisted of an initial burst (9%) on the first day, followed by a daily 4% release for the following 40 days, resulting in 91% of the BSA release in a near linear manner. The released BSA remained intact according to SDS-PAGE data. Cytotoxicity and histopathology studies showed low toxicity in HeLa cells and good tissue biocompatibility in mouse brain, respectively. PLAEEP is a promising biodegradable polymer for controlled drug delivery.

Animals↗

PubMed2003

A genome sequence of novel SARS-CoV isolates: the genotype, GD-Ins29, leads to a hypothesis of viral transmission in South China.

We report a complete genomic sequence of rare isolates (minor genotype) of the SARS-CoV from SARS patients in Guangdong, China, where the first few cases emerged. The most striking discovery from the isolate is an extra 29-nucleotide sequence located at the nucleotide positions between 27,863 and 27,864 (referred to the complete sequence of BJ01) within an overlapped region composed of BGI-PUP5 (BGI-postulated uncharacterized protein 5) and BGI-PUP6 upstream of the N (nucleocapsid) protein. The discovery of this minor genotype, GD-Ins29, suggests a significant genetic event and differentiates it from the previously reported genotype, the dominant form among all sequenced SARS-CoV isolates. A 17-nt segment of this extra sequence is identical to a segment of the same size in two human mRNA sequences that may interfere with viral replication and transcription in the cytosol of the infected cells. It provides a new avenue for the exploration of the virus-host interaction in viral evolution, host pathogenesis, and vaccine development.

Base Sequence↗

PubMed2003

The M protein of SARS-CoV: basic structural and immunological properties.

We studied structural and immunological properties of the SARS-CoV M (membrane) protein, based on comparative analyses of sequence features, phylogenetic investigation, and experimental results. The M protein is predicted to contain a triple-spanning transmembrane (TM) region, a single N-glycosylation site near its N-terminus that is in the exterior of the virion, and a long C-terminal region in the interior. The M protein harbors a higher substitution rate (0.6% correlated to its size) among viral open reading frames (ORFs) from published data. The four substitutions detected in the M protein, which cause non-synonymous changes, can be classified into three types. One of them results in changes of pI (isoelectric point) and charge, affecting antigenicity. The second changes hydrophobicity of the TM region, and the third one relates to hydrophilicity of the interior structure. Phylogenetic tree building based on the variations of the M protein appears to support the non-human origin of SARS-CoV. To investigate its immunogenicity, we synthesized eight oligopeptides covering 69.2% of the entire ORF and screened them by using ELISA (enzyme-linked immunosorbent assay) with sera from SARS patients. The results confirmed our predictions on antigenic sites.

Amino Acid Sequence↗

PubMed2003

The structure analysis and antigenicity study of the N protein of SARS-CoV.

The Coronaviridae family is characterized by a nucleocapsid that is composed of the genome RNA molecule in combination with the nucleoprotein (N protein) within a virion. The most striking physiochemical feature of the N protein of SARS-CoV is that it is a typical basic protein with a high predicted pI and high hydrophilicity, which is consistent with its function of binding to the ribophosphate backbone of the RNA molecule. The predicted high extent of phosphorylation of the N protein on multiple candidate phosphorylation sites demonstrates that it would be related to important functions, such as RNA-binding and localization to the nucleolus of host cells. Subsequent study shows that there is an SR-rich region in the N protein and this region might be involved in the protein-protein interaction. The abundant antigenic sites predicted in the N protein, as well as experimental evidence with synthesized polypeptides, indicate that the N protein is one of the major antigens of the SARS-CoV. Compared with other viral structural proteins, the low variation rate of the N protein with regards to its size suggests its importance to the survival of the virus.

Amino Acid Motifs↗

PubMed2003

The C-terminal portion of the nucleocapsid protein demonstrates SARS-CoV antigenicity.

In order to develop clinical diagnostic tools for rapid detection of the SARS-CoV (severe acute respiratory syndrome-associated coronavirus) and to identify candidate proteins for vaccine development, the C-terminal portion of the nucleocapsid (NC) gene was amplified using RT-PCR from the SARS-CoV genome, cloned into a yeast expression vector (pEGH), and expressed as a glutathione S-transferase (GST) and Hisx6 double-tagged fusion protein under the control of an inducible promoter. Western analysis on the purified protein confirmed the expression and purification of the NC fusion proteins from yeast. To determine its antigenicity, the fusion protein was challenged with serum samples from SARS patients and normal controls. The NC fusion protein demonstrated high antigenicity with high specificity, and therefore, it should have great potential in designing clinical diagnostic tools and provide useful information for vaccine development.

Antigens, Viral↗

PubMed2003

The epitope study on the SARS-CoV nucleocapsid protein.

The nucleocapsid protein (N protein) has been found to be an antigenic protein in a number of coronaviruses. Whether the N protein in severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is antigenic remains to be elucidated. Using Western blot and Enzyme-linked Immunosorbent Assay (ELISA), the recombinant N proteins and the synthesized peptides derived from the N protein were screened in sera from SARS patients. All patient sera in this study displayed strong positive immunoreactivities against the recombinant N proteins, whereas normal sera gave negative immunoresponses to these proteins, indicating that the N protein of SARS-CoV is an antigenic protein. Furthermore, the epitope sites in the N protein were determined by competition experiments, in which the recombinant proteins or the synthesized peptides competed against the SARS-CoV proteins to bind to the antibodies raised in SARS sera. One epitope site located at the C-terminus was confirmed as the most antigenic region in this protein. A detailed screening of peptide with ELISA demonstrated that the amino sequence from Codons 371 to 407 was the epitope site at the C-terminus of the N protein. Understanding of the epitope sites could be very significant for developing an effective diagnostic approach to SARS.

Blotting, Western↗

PubMed2003

A strategy for searching antigenic regions in the SARS-CoV spike protein.

In the face of the worldwide threat of severe acute respiratory syndrome (SARS) to human life, some of the most urgent challenges are to develop fast and accurate analytical methods for early diagnosis of this disease as well as to create a safe anti-viral vaccine for prevention. To these ends, we investigated the antigenicity of the spike protein (S protein), a major structural protein in the SARS-coronavirus (SARS-CoV). Based upon the theoretical analysis for hydrophobicity of the S protein, 18 peptides were synthesized. Using Enzyme-Linked Immunosorbent Assay (ELISA), these peptides were screened in the sera from SARS patients. According to these results, two fragments of the S gene were amplified by PCR and cloned into pET-32a. Both S fragments were expressed in the BL-21 strain and further purified with an affinity chromatography. These recombinant S fragments were confirmed to have positive cross-reactions with SARS sera, either by Western blot or by ELISA. Our results demonstrated that the potential epitope regions were located at Codons 469-882 in the S protein, and one epitope site was located at Codons 599-620. Identification of antigenic regions in the SARS-CoV S protein may be important for the functional studies of this virus or the development of clinical diagnosis.

Antigens, Viral↗

PubMed2003

Genome organization of the SARS-CoV.

Annotation of the genome sequence of the SARS-CoV (severe acute respiratory syndrome-associated coronavirus) is indispensable to understand its evolution and pathogenesis. We have performed a full annotation of the SARS-CoV genome sequences by using annotation programs publicly available or developed by ourselves. Totally, 21 open reading frames (ORFs) of genes or putative uncharacterized proteins (PUPs) were predicted. Seven PUPs had not been reported previously, and two of them were predicted to contain transmembrane regions. Eight ORFs partially overlapped with or embedded into those of known genes, revealing that the SARS-CoV genome is a small and compact one with overlapped coding regions. The most striking discovery is that an ORF locates on the minus strand. We have also annotated non-coding regions and identified the transcription regulating sequences (TRS) in the intergenic regions. The analysis of TRS supports the minus strand extending transcription mechanism of coronavirus. The SNP analysis of different isolates reveals that mutations of the sequences do not affect the prediction results of ORFs.

Amino Acid Substitution↗

PubMed2003

Assessment of immunoreactive synthetic peptides from the structural proteins of severe acute respiratory syndrome coronavirus.

BACKGROUND: The widespread threat of severe acute respiratory syndrome (SARS) to human life has spawned challenges to develop fast and accurate analytical methods for its early diagnosis and to create a safe antiviral vaccine for preventive use. Consequently, we thoroughly investigated the immunoreactivities with patient sera of a series of synthesized peptides from SARS-coronavirus structural proteins. METHODS: We synthesized 41 peptides ranging in size from 16 to 25 amino acid residues of relatively high hydrophilicity. The immunoreactivities of the peptides with SARS patient sera were determined by ELISA. RESULTS: Four epitopic sites, S599, M137, N66, and N371-404, located in the SARS-coronavirus S, M, and N proteins, respectively, were detected by screening synthesized peptides. Notably, N371 and N385, located at the COOH terminus of the N protein, inhibited binding of antibodies to SARS-coronavirus lysate and bound to antibodies in >94% of samples from SARS study patients. N385 had the highest affinity for forming peptide-antibody complexes with SARS serum. CONCLUSIONS: Five peptides from SARS structural proteins, especially two from the COOH terminus of the N protein, appear to be highly immunogenic and may be useful for serologic assays. The identification of these antigenic peptides contributes to the understanding of the immunogenicity and persistence of SARS coronavirus.

Animals↗

PubMed2003

[Reliability of detecting SARS-CoV antibody for diagnosis of SARS].

OBJECTIVE: To discuss the reliability of SARS-CoV antibody detection for SARS diagnosis. METHODS: Using SARS-CoV ELISA kit to detect relevant antibody in fresh serum of healthy, fever, probable, and suspect cases. RESULTS: The positive rate is 0%, 40%, and 95% respectively in healthy, probable, and suspect cases. CONCLUSIONS: It is reliable to detect SARS-CoV antibody in late suspect patients, but there will be high false-positive result in ordinary fever cases.

Adolescent↗