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Biomedical subjects

Jian Lin

Publications and source records attributed to Jian Lin.

36 records · Page 2Linked to original sources
PubMed2005

[Primary artery erectile dysfunction: one case report].

OBJECTIVE: To evaluate the relationship between the deformation of penile artery and the primary artery erectile dysfunction, and to improve the treatment and diagnosis of primary artery erectile dysfunction. METHODS: One case of primary artery erectile dysfunction was presented with its primary clinic data. RESULTS: The dorsal artery of the penis was thin and the bilateral penile arteries were lacking by arteriography. The implantation of a penile prosthesis significantly improved the patient's erectile function. CONCLUSION: The primary artery erectile dysfunction is a relatively rare disease. The possibility of primary artery erectile dysfunction should be kept in mind. Penile prosthesis implantation is an effective means for the treatment of primary artery erectile dysfunction.

Adult↗
PubMed2004

Differential interaction of 3-hydroxy-3-methylglutaryl-coa reductase inhibitors with ABCB1, ABCC2, and OATP1B1.

The present study examined the interaction of four 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (atorvastatin, lovastatin, and simvastatin in acid and lactone forms, and pravastatin in acid form only) with multidrug resistance gene 1 (MDR1, ABCB1) P-glycoprotein, multidrug resistance-associated protein 2 (MRP2, ABCC2), and organic anion-transporting polypeptide 1B1 (OATP1B1, SLCO21A6). P-glycoprotein substrate assays were performed using Madin-Darby canine kidney (MDCK) cells expressing MDR1, and the efflux ratios [the ratio of the ratio of basolateral-to-apical apparent permeability and apical-to-basolateral permeability between MDR1 and MDCK] were 1.87, 2.32/4.46, 2.17/3.17, and 0.93/2.00 for pravastatin, atorvastatin (lactone/acid), lovastatin (lactone/acid), and simvastatin (lactone/acid), respectively, indicating that these compounds are weak or moderate substrates of P-glycoprotein. In the inhibition assays (MDR1, MRP2, Mrp2, and OATP1B1), the IC50 values for efflux transporters (MDR1, MRP2, and Mrp2) were >100 microM for all statins in acid form except lovastatin acid (>33 microM), and the IC50 values were up to 10-fold lower for the corresponding lactone forms. In contrast, the IC50 values for the uptake transporter OATP1B1 were 3- to 7-fold lower for statins in the acid form compared with the corresponding lactone form. These data demonstrate that lactone and acid forms of statins exhibit differential substrate and inhibitor activities toward efflux and uptake transporters. The interconversion between the lactone and acid forms of most statins exists in the body and will potentially influence drug-transporter interactions, and may ultimately contribute to the differences in pharmacokinetic profiles observed between statins.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

High-yield expression of recombinant SARS coronavirus nucleocapsid protein in methylotrophic yeast Pichia pastoris.

AIM: Nucleocapsid (N) protein plays an important role in reproduction and pathological reaction of severe acute respiratory syndrome (SARS) coronavirus (SCoV), the antigenicity of the protein is better than spike (S) protein. This study was to find a highly specific and antigenic recombinant SCoV nucleocapsid (rSCoVN) protein, and to provide a basis for further researches on early diagnosis of SARS. METHODS: Full length cDNA of SCoV nucleocapsid (SCoVN) protein was amplified through polymerase chain reaction (PCR) and cloned into yeast expression vector pPIC3.5K to construct plasmid of pPIC3.5K-SCoVN. The plasmid was linearized and then transformed into Pichia pastoris (P.pastoris) GS115 (His-Mut+) by electroporation. His(+)Mut(+) recombinant strains were identified by PCR and cultivated on MM/MD plates. The influence of different factors on biomass and rSCoVN protein production during induction phase, such as various induction media, dissolved oxygen (DO) and different final concentrations of methanol, was subsequently studied. The expression level and activation were detected by SDS-PAGE and Western-blot respectively. RESULTS: All of the recombinants were His(+)Mut(+) after transformation of P.pastoris with linearized plasmids. The BMMY medium was optimal for recombinant ScoVN (rSCoVN) protein expression and growth of the recombinant strains. The final optimal concentration of methanol was 20 mL/L, the DO had a significant effect on rSCoVN protein expression and growth of recombinant strains. The rSCoVN protein expressed in recombinant strains was about 8% of the total cell protein, 520 mg/L of rSCoVN protein was achieved, and a maximum cell A at 600 nm of 62 was achieved in shake flask culture. The rSCoVN protein had a high specificity against mouse-anti-SARS-CoVN-mAb and SARS positive sera, but had no cross-reaction with normal human serum. The biological activity of rSCoVN expressed in P.pastoris was about 4-fold higher than that expressed in E.coli when the same rSCoVN protein quantity was used. CONCLUSION: Active recombinant severe acute respiratory syndrome (SARS) coronavirus nucleocapsid (rSCoVN) protein can be successfully expressed in recombinant methylotrophic yeast P.pastoris GS115. The rSCoVN protein has a high specificity against SARS-CoVN-mAb and SARS positive sera, but has no cross-reaction with normal human serum. This provides a basis for further researches on the early diagnosis of SARS and the mechanism of SCoV.

Bacteriological Techniques↗
PubMed2004

Mutational analysis of essential interactions involved in the assembly of hepatitis E virus capsid.

The hepatitis E virus (HEV) capsid consists of a single structural protein, a portion of which is engaged in isosahedral contact to form a basal shell, and another portion in dimeric contact to form the homodimers protruding from the shell. Previous studies revealed that homodimers of the truncated HEV capsid proteins, E2 (amino acids 394-606) and p239 (amino acids 368-606), model dominant antigenic determinants of HEV. Immunization with these proteins protected rhesus monkeys against the virus, and three monoclonal antibodies against the homodimers could neutralize HEV infectivity and/or immune-capture of the virus. Furthermore, homodimers of p239 further interact to form particles of 23 nm diameter, rendering it an efficacious candidate vaccine. In light of this we postulate that the interactions involved in the formation of the homodimers and particles might be similar to those involved in assembly of the virus capsid. Presently, mutational analysis was carried out to identify these sites of interactions. The site of dimeric interactions was located to a cluster of six hydrophobic amino acids residues, Ala597, Val598, Ala599, Leu601, and Ala602; furthermore, the site involved in particle formation was located at amino acids 368-394. The possibility that these sites are also involved in assembly of the virus capsid is supported by the fact that they are located at two major and highly conserved hydrophobic regions of the HEV structural protein.

Capsid Proteins↗
PubMed2004

Young monozygotic twin sisters with fundus albipunctatus and cone dystrophy.

OBJECTIVE: To describe young monozygotic twin sisters with fundus albipunctatus (a type of autosomal recessive stationary night blindness caused by mutations of the 11-cis retinol dehydrogenase gene [RDH5]) associated with cone dystrophy, previously reported in elderly men. METHODS: Ophthalmologic examinations were performed, and the RDH5 gene was analyzed by direct genomic sequencing. RESULTS: Twin 23-year-old sisters with high myopic refractive errors of approximately -13 diopters were diagnosed as having fundus albipunctatus. Their photopic electroretinographic responses were markedly reduced, and cone dystrophy was diagnosed. One twin had macular degeneration with reduced best-corrected visual acuity, while the other twin had normal maculae with good visual acuity. A compound heterozygous mutation, Val132Met and Arg280His, in the RDH5 gene was found in both sisters. CONCLUSIONS: Cone dystrophy can be present in patients with fundus albipunctatus, not only elderly men but also young women. The clinical severity differed between monozygotic twins with fundus albipunctatus and cone dystrophy.Clinical Relevance The patient's sex is not critical for the presence of cone dystrophy in patients with fundus albipunctatus. The discordant findings in the twins indicate that factors other than genetics influenced the phenotype.

Adult↗
PubMed2004

[Evaluation of the reliability of three different hepatitis E diagnosis reagents on the clinical acute hepatitis E].

OBJECTIVE: To evaluate the reliability of different hepatitis E diagnosis reagent tests on the acute hepatitis E. METHODS: Three acute hepatitis E diagnosis tests, E2-IgM (Wantai, China), GL-IgM and GL-IgG (Genelabs, Singapore) were compared for their reliability in a sera panel composed by 273 healthy individuals and 525 hepatitis. RESULTS: The specificity of E2-IgM on the diagnosis of acute hepatitis E was 100.0%, it was significantly higher than GL-IgM (96.7%) and GL-IgG (85.4%). The sensitivity of E2-IgM and GL-IgG were 97.9% and 93.8% respectively, both significantly higher than GL-IgM (72.9%). Among 65 acute hepatitis cases being positive on GL-IgM test but negative on E2-IgM, 58 (89.2%) cases were found to be positive with anti-hepatitis A virus IgM, it indicated that the GL-IgM test might be interfered by other IgM antibodies on serum. CONCLUSION: E2-IgM is a good test for the diagnosis of acute hepatitis E.

Acute Disease↗
PubMed2004

[Effect of macrophage inflammatory protein-1alpha and its mRNA on airway inflammation of mouse asthma model].

OBJECTIVE: To study the effect of macrophage inflammatory protein-1alpha(MIP-1alpha) and its mRNA on airway inflammation of mouse with induced asthma. METHODS: Seventy male BALB/C mice were randomly divided into the control group and asthma group (including 7 subgroups, 10 mice each). The control group included group A(24) (the lavaging subgroup was sacrificed 24 h after the last challenge) and group A(0) (the non-lavaging subgroup was sacrificed from 18 h to 24 h after the last challenge); asthma group included group B(3) (the lavaging subgroup was sacrificed 3 h after the last challenge), group B(8) (the lavaging subgroup was sacrificed 8 h after the last challenge), group B(24) (the lavaging subgroup was sacrificed 24 h after the last challenge), group B(36) (the lavaging subgroup was sacrificed 36 h after the last challenge) and group B(0) (the non-lavaging subgroup was sacrificed from 18 h to 24 h after the last challenge). In the experiment, the mice model of asthma was established by the ovalbumin (OVA) challenge methods. Eosinophils (EOS) numbers and differentiated cell numbers in bronchoalveolar lavage fluid (BALF) were counted; the concentrations of MIP-1alpha in serum and BALF were measured by sandwich enzyme-linked immunosorbent assay (sandwich ELISA); the protein expressions of MIP-1alpha were detected by immunohistochemical techniques; the mRNA expressions of MIP-1alpha were determined by in situ hybridization technique. RESULTS: (1) The concentrations of MIP-1alpha in BALF and serum of group B(3) [(30.2 +/- 4.2) pg/ml, (30.8 +/- 4.6) pg/ml], group B(8) [(35.3 +/- 4.9) pg/ml, (34.9 +/- 5.1) pg/ml], group B(24) [(42.9 +/- 5.8) pg/ml, (41.7 +/- 6.3) pg/ml] and group B(36) [(37.8 +/- 4.7) pg/ml, (35.7 +/- 4.9) pg/ml] were significantly higher than those of group A(24) [(20.9 +/- 3.8) pg/ml, (22.4 +/- 4.3) pg/ml] (P < 0.01); the concentrations of MIP-1alpha in BALF and serum went up at 3 h, reached peak at 24 h, and had descended at 36 h. (2) Immunohistochemistry showed that the protein expressions of MIP-1alpha around the bronchus of group B(0) [(26.4 +/- 6.2)%] were significantly elevated as compared to those of group A(0) [(10.3 +/- 2.5)%] (P < 0.01), the epithelial cell was the chief expression cell. (3) In situ hybridization showed that the mRNA expressions of MIP-1alpha around the bronchus of group B(0) [(23.9 +/- 4.2)%] were significantly increased when compared to those of group A(0) [(8.7 +/- 1.8)%] (P < 0.01), the epithelial cell was the chief expression cell. (4) There was a significant correlation between the concentrations of MIP-1alpha and the numbers of EOS in BALF and between the concentrations of MIP-1alpha and the percentage of EOS numbers in the total cell numbers (EOS%) in BALF. CONCLUSIONS: MIP-1alpha protein and MIP-1alpha mRNA were found strongly expressed in mouse asthma model, the epithelial cell was the chief expression cell; the kinetic characteristic of MIP-1alpha showed that its level increased at 3 h, reached peak at 24 h and declined at 36 h; MIP-1alpha and EOS gathering had a significant correlation.

Animals↗
PubMed2004

[Particulate recombinant hepatitis E virus capsid protein and its antigenicity and immunogenicity].

An E. coli expressed recombinant antigen NE2 was reported to aggregate into homo-oligomer, and can induce protective antibodies on rhesus monkey, but its immunogenicty was much weak after being purified. In this study, three N-terminal extension mutant of NE2 were expressed in E. coli, one of which named HEV 239 was found to aggregate into particle. HEV 239 antigen had good reactivity with sera of hepatitis E patients. The reactivity of HEV 239 against neutralization monoclonal antibody 8C11 was similar as NE2 antigen, while the reactivity of it against another neutralization monoclonal antibody 8H3 is much better than NE2 antigen, which indicated better antigenicity of HEV 239 than NE2. The diameter of purified HEV 239 particulate antigen was between 15 nm to 30 nm. The ED50 of immunization of HEV 239 particle adsorbed by aluminum adjuvant to BALB/c mice was between 0.08 microg to 0.25 microg. In contrast, the seraconversion rate of mice immunized by NE2 antigen adsorbed by aluminium adjuvant was only 25% on 60 microg vaccination. These results suggested that HEV 239 antigen particle has better immunogenicity as well as antigenicity than those of NE2 antigen, so it is a better vaccine candidate against HEV.

Animals↗
PubMed2004

[Interface domain of hepatitis E virus capsid protein homodimer].

Hepatitis E is a main cause of acute viral hepatitis in developing countries where it occurs as sporadic cases and in epidemics form. The causative agent, hepatitis E virus, is transmitted primarily by the fecal-oral route. The approximately 7.5 kb positive-sense single-strand RNA genome includes three open reading frames (ORFs), one of which (ORF2) is postulated to encode the major viral capsid protein (pORF2) of 660 amino acid residues. We earlier showed that a bacterially expressed peptide, designated as NE2, located from amino acid residues 394 to 606 of ORF2, was found to aggregate into homodimer to at least hexamer. To understand the interface domains within this peptide vital for dimerization and formation of major neutralizing epitopes, NE2 protein underwent terminal-truncated and site-directed mutation. The hydrophobic region, ORF2 aa597-aa602 (AVAVLA), played a key role in oligomerization. Any amino acid residue of this region replaced with glutamic acid residue, the peptide can not refold as homodimer and/or oligomer. The immunoreactivities of these mutant peptides, blotted with anti-HEV neutralizing monoclonal antibody (8C11) and convalescent human sera, show associated to the formation of homodimer. The intermolecular contact region on homodimer was investigated by chemical cross-linking of two site-directed cysteines. When the alanine on aa597 site mutated with cysteine, two different homodimers were found in SDS-PAGE analysis. One (42kD) can be disassociated with 8mol/L urea, which is postulated to form by virtue of hydrophobic interaction, and the other (60kD) falls apart with the reductant DTT present. The exact conformation, generating the cross-linking reaction of cysteines, was further investigated by induced-oxidation on monomer and hydrophobic homodimer of A597C protein with GSH/GSSG. And the results revealed, it is the conformation of hydrophobic homodimer that induces the disulfide bond come into being, instead of the one of monomer. So the aa597 site was verified to be located on interface domain of hydrophobically interacting homodimeric complex. To evaluate the biological significance of hydrophobicity of interface domain, we searched natural variations as to the region on all available databases with NCBI blast program. All variations on these amino acid residues kept higher hydrophobicity, which suggests that the hydrophobic domain is critical for the assemblage and propagation of HEV. NE2 N-terminal deletions up to aa458 had no effect on dimerization and took no exact part in formation of major neutralizing epitopes, but the fragment may act as helper for the formation of major neutralizing epitopes on NE2. Interestingly, the C-terminus aa605-aa660 of ORF2 can also act as helper instead of the N-terminus of NE2. This study suggests an interface domain of NE2 might be vital for HEV capsomer assembly and formation of major neutralizing epitopes. These results may offer clues to the rational design of recombinant anti-HEV vaccine.

Capsid Proteins↗
PubMed2003

An ultraslow-spreading class of ocean ridge.

New investigations of the Southwest Indian and Arctic ridges reveal an ultraslow-spreading class of ocean ridge that is characterized by intermittent volcanism and a lack of transform faults. We find that the mantle beneath such ridges is emplaced continuously to the seafloor over large regions. The differences between ultraslow- and slow-spreading ridges are as great as those between slow- and fast-spreading ridges. The ultraslow-spreading ridges usually form at full spreading rates less than about 12 mm yr(-1), though their characteristics are commonly found at rates up to approximately 20 mm yr(-1). The ultraslow-spreading ridges consist of linked magmatic and amagmatic accretionary ridge segments. The amagmatic segments are a previously unrecognized class of accretionary plate boundary structure and can assume any orientation, with angles relative to the spreading direction ranging from orthogonal to acute. These amagmatic segments sometimes coexist with magmatic ridge segments for millions of years to form stable plate boundaries, or may displace or be displaced by transforms and magmatic ridge segments as spreading rate, mantle thermal structure and ridge geometry change.

Journal Article↗
PubMed2003

Mechanism of bactericidal and fungicidal activities of textiles covalently modified with alkylated polyethylenimine.

Our previous studies have led to a novel "nonrelease" approach to making materials bactericidal by covalently attaching certain moderately hydrophobic polycations to their surfaces. In the present work, this strategy is extended beyond the heretofore-used nonporous materials to include common woven textiles (cotton, wool, nylon, and polyester). Pieces of such cloths derivatized with N-hexylated+methylated high-molecular-weight polyethylenimine (PEI) are strongly bactericidal against several airborne Gram-positive and Gram-negative bacteria. In contrast, the immobilized and N-alkylated PEIs of low molecular weight have only a weak, if any, bactericidal activity. These findings support a mechanism of the antibacterial action whereby high-molecular-weight and hydrophobic polycationic chains penetrate bacterial cell membranes/walls and fatally damage them. The bactericidal textiles prepared herein are lethal not only to pathogenic bacteria but to fungi as well.

Alkylation↗
PubMed2003

Making thin polymeric materials, including fabrics, microbicidal and also water-repellent.

A procedure is developed and validated for making a non-functionalized polyolefin fabric/film highly bactericidal and fungicidal which involves a free-radical grafting of maleic anhydride, followed by an attachment of polyethylenimine (PEI) and its subsequent N-alkylation. Separately, cotton fabric coated with a micron layer of a hydrophobic polymer using hot-filament chemical vapor deposition is rendered markedly hydrophobic; if this coating is preceded by immobilization of N-alkyl-PEI, the fabric becomes both water-repellent and bactericidal.

Bacteria↗
PubMed2003

[Analysis of risk factors about stress urinary incontinence in female].

OBJECTIVE: The aim was to assess the prevalence of stress urinary incontinence (SUI) in community dwelling women and to assess the relationship between the various risk factors and this disease. METHODS: Selecting the community of Gulou at random and sending questionnaires to 6,066 women who living there. The questionnaire was designed to investigate the lower urinary tract symptoms, especially urinary incontinence. The questionnaire included some questions such as: age, weight, occupation, the level of education, menopause pregnancy and delivery, delivery through vagina or by cesarean section, the maximum body weight of fetus, chronic disease (hypertension, diabetes mellitus, cough, constipation), operation in abdomen and pelvis, the behaviour of life (smoking, alcohol abuse, exercise), the prevalence and frequency of urinary incontinence, the quality of life and the recognition of this disease. RESULTS: The collecting rate was 92.1% (5,587/6,066). The prevalence of urinary incontinence was 18.1% and the prevalence of SUI was 8.8%. Age (OR: 1.010, 95% CI: 1.001 - 1.025), higher body mass index (OR: 1.092, 95% CI: 1.054 - 1.132), hypertension (OR: 2.342, 95% CI: 1.026 - 5.349), constipation (OR: 1.448, 95% CI: 1.216 - 1.725), multiple abortion (OR: 1.306, 95% CI: 1.113 - 1.533), multipara (OR: 1.205, 95% CI: 1.009 - 1.440), using abdominal pressure in laboring (OR: 1.684, 95% CI: 1.140 - 2.489), straight cutting of perineum (OR: 2.244, 95% CI: 1.162 - 4.334), perineum tear (OR: 2.576, 95% CI: 1.724 - 3.851), infection of perineal incision (OR: 5.988, 95% CI: 1.936 - 18.616) were risk factors of SUI in women. CONCLUSION: Many risk factors can cause urinary incontinence, among them age, pregnancy and childbirth are most important ones.

Adult↗
PubMed2002

Ectopic expression of a COOH-terminal fragment of the human telomerase reverse transcriptase leads to telomere dysfunction and reduction of growth and tumorigenicity in HeLa cells.

The COOH-terminus of telomerase reverse transcriptase (hTERT) has been shown to participatein the nuclear translocation of TERT. Here, we constructed plasmids expressing the COOH-terminal M(r) 27,000 polypeptide of hTERT (hTERTC27) withthe telomerase RNA-binding domains and the reverse transcriptase domains deleted. We showed that ectopic overexpression of this polypeptide caused a defect in telomere maintenance in hTERT-positive HeLa cells, which led to senescence-like growth arrest and apoptosis. The hTERTC27 appears to work by inducing telomere dysfunction, exemplified by significantly increased anaphase chromosome end-to-end fusion events in transfected cells. Significantly, it had no effect on the cellular telomerase enzymatic activity or telomere length. The in vivo effect was further demonstrated as HeLa cells stably expressing hTERTC27 have significantly lower growth rate and reduced tumorigenicity in nude mice xenografts. Results from this study revealed an important function for the COOH terminus of hTERT in maintaining the integrity of telomere structure and chromosome ends, as well as in cell senescence and apoptosis. Furthermore, hTERTC27 provides a new strategy for cancer therapy by inducing telomere dysfunction in cancer cells without affecting the telomerase enzymatic activity.

Animals↗
PubMed2002

Cloning and high level nonfusion expression of recombinant human basic fibroblast growth factor in Escherichia coli.

AIM: To obtain high-level expression of nonfusion recombinant human basic fibroblast growth factor (rhbFGF). METHODS: hbFGF cDNA was prepared from the total RNA of embryonic brain tissue. As a template, the obtained gene was used to clone nonfusion rhbFGF. New primers were employed to alter the translation initiation region (TIR) and reduce the G+C content through nucleotide change. Using pET-3C as vector, the cloned rhbFGF was expressed in BL21 (DE3). RESULTS: rhbFGF was expressed in E coli up to 30 % of the total cellular protein. Cation exchange and heparin affinity chromatography were employed to purify the target protein from the supernatant of bacteria lysate. The bioactivity of the purified rhbFGF was identical with the standard bFGF. CONCLUSION: Modification of TIR is an effective means to increase nonfusion expression rate of recombinant proteins, such as rhbFGF, in E coli.

Base Sequence↗
PubMed2002

[The study of aggregate of the ORF2 peptide of hepatitis E virus expressed in Escherichia coli].

A fragment of hepatitis E virus open reading frame-2(ORF2), located from amino acid residues 394 to 604, was expressed in E. coli. The recombinant protein NE2 was found to form homodimer mostly in SDS-PAGE, which can be dissociated to monomers when treated with urea, and it was recognized more strongly in its dimeric form than the monomer by HEV reactive human serum in Western blotting. Besides, many aggregated form of NE2 from dimer to at least hexamer can be seen in MALDI-TOF-MS. And when the hydrated dynamic semidiameter of NE2 moleculars in PBS was measured as about 4 nm by Dynamic Light Scattering (DLS), being equal to tetramer, but with high polydispersity, which suggested that the NE2 moleculars were existed in PBS in many different sizes. These results suggested that the recombinant NE2 can aggregate into several oligomer forms, the association in the dimer is most strong, and dimers can assemble further to form some super-structure.

Dimerization↗
PubMedDate not supplied

Bactericidal properties of flat surfaces and nanoparticles derivatized with alkylated polyethylenimines.

We previously discovered that covalently coating glass and plastic slides with certain long poly(vinyl-N-alkylpyridinium) chains enables the resultant surfaces to kill a variety of airborne and waterborne bacteria on contact. In the present study, these findings have been extended to an unrelated polymer class, polyethylenimines (PEIs). Alkylated PEIs attached to flat macroscopic surfaces and to those of nanoparticles make these materials highly bactericidal toward both Gram-positive and Gram-negative pathogenic bacteria. Systematic chemical modifications of the immobilized PEI conducted herein shed light on the relationship between the structure of the polymer and the antibacterial efficiency of the resultant coating.

Coated Materials, Biocompatible↗