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Biomedical subjects

Lei Han

Publications and source records attributed to Lei Han.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Reversal of the multidrug resistance in human hepatocellular carcinoma cells by recombinant adenoviral delivery of the MRP antisense RNA in vitro].

OBJECTIVE: To explore the effect of multidrug resistance-associated protein (MRP) antisense RNA mediated by recombinant adenoviruses on reversal of the multidrug resistance in human drug-resistant hepatocellular carcinoma (HCC) cells. METHODS: The HCC cells were first treated in vitro by the recombinant adenoviruses containing antisense MRP. Chemosensitivity of all of the cells to ADM and DNR was determined by MTT assay. The levels of the MRP mRNA and its product P190 were measured by RT-PCR and flow cytometry (FCM) respectively according to the time after transfection. The accumulation of the DNR in these cells was analyzed by FCM simultaneously. RESULTS: IC50 of the cells infected by Ad-Asmrp to ADM and DNR was 0.487 microg/ml and 0.328 microg/ml respectively, with the factors of resistance (RF) decreased by 36.8 and 35.4 respectively (P < 0.05). Continuous decrease in levels of MRP mRNA and P190 was observed 24 h and 48 h after infection respectively (P < 0.01). The intracellular DNR accumulation was increased simultaneously in the Ad-Asmrp transfectants (P < 0.001). CONCLUSIONS: MRP antisense RNA mediated by recombinant adenoviruses could increase chemosensitivity and partially reverse the MDR in HCC cells in vitro by inhibit expression of MRP gene. The study would provide experimental basis for the reversal of MDR in HCC by antisense RNA technology mediated by recombinant adenoviruses.

Adenoviridae↗
PubMed2005

Recombinant nucleoprotein-based serological diagnosis of Crimean-Congo hemorrhagic fever virus infections.

An enzyme-linked immunosorbent assay (ELISA) using recombinant nucleoprotein (rNP) was reported for the detection of immunoglobulin G (IgG) antibodies to Crimean-Congo hemorrhagic fever (CCHF) virus (CCHFV). The immunoglobulin M (IgM)-capture ELISA was developed for the diagnosis of CCHFV infections, using CCHFV rNP as an antigen. These newly developed assays were applied to a study of a CCHF-outbreak and evaluated with sera collected from patients diagnosed as having CCHF by positive reverse transcription-polymerase chain reaction (RT-PCR) and by detection of IgG response. IgM antibodies to CCHFV were detected in 10 of the 13 patients. IgM antibodies to the rNP of CCHFV were detected by the CCHFV rNP-based IgM-capture ELISA in all 6 patients in whom IgG responses were demonstrated, while it was not detected in the 10 patients in whom IgG responses were not demonstrated. Furthermore, the IgM antibodies were detected in 6 of the 61 residents living a CCHF endemic area during the endemic season, while it was not detected in any of the 48 Japanese residents that had never visited the CCHF endemic area. It is concluded that this newly developed CCHFV rNP-based IgM-capture ELISA is a useful method for the diagnosis of CCHFV infections.

Adolescent↗
PubMed2005

Antigen-capture enzyme-linked immunosorbent assay for the diagnosis of crimean-congo hemorrhagic fever using a novel monoclonal antibody.

An antigen-capture enzyme-linked immunosorbent assay (ELISA) was developed for the diagnosis of Crimean-Congo hemorrhagic fever (CCHF) using a novel monoclonal antibody, 1B7, to the recombinant nucleoprotein (rNP) of CCHF virus (CCHFV) Chinese strain 8402. This ELISA detected at least 2 ng/100 microl of CCHFV rNP of 8402 and of the Nigeria strain Ibr 10200, and also detected authentic nucleoproteins (NP) of Chinese strains. Although the sensitivity of the ELISA was lower than that of nested reverse transcription polymerase chain reaction (RT-PCR), it was able to detect nucleoproteins in acute sera of CCHF patients. The presence of anti-CCHFV IgG decreased the sensitivity of the ELISA, possibly due to competition with 1B7, and this would tend to limit application of the ELISA. However, the method may be useful for the diagnosis of CCHF patients in the acute stage of illness, especially in laboratories not equipped with RT-PCR testing capabilities.

Animals↗
PubMed2005

[Recombinant adenovirus vectors carrying antisense MMP2 inhibit invasion of HCC cells in vitro].

OBJECTIVES: To construct a recombinant adenoviral vector carrying antisense matrix metalloproteinase-2 (MMP2) and to study its inhibitory effects on the invasiveness and migratory capacity of hepatocellular carcinoma (HCC) cell line HepG2 in vitro. METHODS: Total RNA was extracted from HCC. Then a 500 bp fragment at the 5' end of the human MMP2 cDNA sequence was synthesized by polymerase chain reaction (PCR) and was reversely inserted into the multiclone site (MCS) of the shuttle plasmid pAdTrack-CMV. With the resultant plasmid and the backbone plasmid pAdEasy-1, the homologous recombination took place in the E.coli BJ5183 and the recombinant adenoviral plasmid carrying the antisense MMP2 gene was constructed. The adenovirus (Ad-MMP2AS) was packaged and amplified in the HEK 293 cells and the viral titer was checked by GFP. Using the Boyden chamber model, the influence of Ad-MMP2AS on the invasion ability of HepG2 cells was determined in vitro. RESULTS: The recombinant adenovirus vector carrying antisense MMP2 was constructed successfully and a strong green fluorescence was observed in HepG2 cells under a fluorescence microscope. The viral titer was 1 x 10(8); Ad-MMP2AS can effectively inhibit the penetrating capacity of HepG2 cells through Matrigel in vitro. CONCLUSION: The recombinant adenovirus with antisense MMP2 can effectively inhibit the invasiveness and migratory capacity of HepG2 in vitro and may have potential in treating HCC.

Adenoviridae↗
PubMed2005

[Morphological and molecular biological peculiarities of the experimental autoimmune prostatitis rat model].

OBJECTIVE: To observe the morphological and molecular biological peculiarities of the experimental autoimmune prostatitis (EAP) rat model made by SC purified prostate protein twice with immune adjuvant. METHODS: Male rats were intradermally immunized with a saline extract of male rat prostate glands (RPG) in Freund's complete adjuvant (FCA) and Pertussis-Diphtheria-Tetanus vaccine 0.5 ml i.p. at the 0 and 30th day, and the concentrations of the extract were respectively 5 mg/ml, 10 mg/ml and 15 mg/ml. At the 45th day, the rats were sacrificed and the morphological and molecular biological changes of the prostate specimens were observed to determine the effective concentration of RPG for a successful model. RESULTS: The expression of inflammation genes such as TNF-alpha, IL-1beta, IL-2 and iNOS obviously increased in the high-dosage model group; LM, EM and in situ hybridization revealed appearant chronic inflammation response, but this was not the case in the other two dosage groups. CONCLUSION: 15 mg/ml RPG mixed with FCA (1:1) 1.0 ml SC with Pertussis-Diphtheria-Tetanus vaccine 0.5 ml i.p. was an effective dosage for the successful model in our experiment.

Animals↗
PubMed2005

[An experimental study of recombinant adenovirus microsphere carrying antisense multidrug resistance-associated protein gene for reversing MRP of hepatocellular carcinoma in vitro].

OBJECTIVE: To conduct an in vitro study on the effect of recombinant adenovirus microsphere encapusulated antisense MRP (as-mrp) for use in the gene therapy to overcome drug resistance in hepatocellular carcinoma. METHODS: Recombinant adenovirus microsphere encapusulated as-mrp was transfected into hepatocellular carcinoma multidrug resistance cells HepG2/ADM, the fluorescence intensity of transfected cells were observed at 48 hours and 120 hours after transfection. in vitro drug sensitivity was measured by MTT assay; the resistant index of andromycin resistant variants was determined by drawing the cell dosage reaction curves. The levels of MRP mRNA expression were detected by RT-PCR and the ratio of MRP mRNA/beta-actin was detected. Intracelluar rubidomycin (DNR) concertration was examined by flow cytometry (FCM). RESULTS: More than 90% of the HepG2/ADM cells could be transfected when microspheres being 10 mg. Adv microsphere inhibited the expression of mRNA in HepG2/ADM and enhanced the sensitivity of HepG2/ADM to chemotherapeutic drug. CONCLUSION: Recombinant adenovirus microsphere encapusulated as-mrp could effectively reverse HepG2/ADM cells, which would provide an experimental basis for the methods of reversing the multidrug resistance in human hepatocellular carcinoma.

Adenoviridae↗
PubMed2005

[Effect of beta-carotene supplementation on DNA oxidative and alkylation damage in rats].

OBJECTIVE: To investigate the effect of beta-carotene (P-C) supplementation on DNA oxidative and alkylation damage in rats. METHODS: Rats were randomly divided into five groups. The first group was no beta-C, and the second, the third, the forth and the fifth groups were daily supplemented with 0.071, 0.355, 4.28 and 15.0 mg/(kg x d). The content of plasma VA was analyzed by fluorescent spectrometry. DNA damage and oxidative damage induced by H2O2 were detected by single-cell gel electrophoresis (SCGE) and O6-Methyl-guanine (O6-MeG) was measured by high performance capillary zone electrophoresis. RESULTS: After 8 weeks trial, the results showed that levels of plasma retinol converted from beta-C decreased by 135 microg/L in the beta-C deficiency group, which were much lower than 276 - 306 microg/L in other four beta-C supplement groups (P < 0.01). Intrinsic damage of DNA was more severe in the group of beta-C deficiency than the groups supplemented with beta-C (P < 0.01). The lower DNA oxidative damage of lymphocyte, which was induced by H2O2, was found in 4.28 mg/(kg x d) group than deficiency and other supplement groups (P < 0.05). O6-Methyl-guanine of the supplement groups was lower than the beta-C deficient group at the 6th week and 8th week (P < 0.05). O6-Methyl-guanine did not decreasing with the dose increasing and the lowest in the 4.28mg/(kg x d) group. CONCLUSION: Beta-C or retinol deficiency and over intake such as 15.0 mg/(kg x d) as well might cause or promote DNA damage, and a moderate amount such as 4.280 mg/(kg x d) could improve antioxidative and decrease DNA damage effectively.

Alkylation↗
PubMed2005

[Inhibition of adenovirus-mediated gene transfer of antisense matrix metalloproteinase-2 on hepatocellular carcinoma growth in vivo].

OBJECTIVE: To investigate if a recombinant adenoviral vector carrying antisense matrix metalloproteinase-2 (MMP2) gene would inhibit the growth of hepatocellular carcinoma (HCC) in vivo. METHODS: Using the recombinant adenoviral vector carrying antisense MMP2 gene (Ad-MMP2AS) which was constructed by us previously, to infect the human HCC cell line (Bel-7402). Then the invasiveness of the Bel-7402 cells was assayed in Matrigel, and the production of MMP2 in the Bel-7402 cells was detected with Western blotting analysis and Gelatin zymography. Then the Ad-MMP2AS-infected cells were subcutaneously inoculated in nude mice. After tumors developed, Ad-MMP2AS was injected intratumorally into pre-existing tumors. The tumors were removed, sectioned, and stained with H E. RESULTS: Compared with PBS or Ad-CMV-infected cells, the infected Bel-7402 cells with Ad-MMP2AS injections significantly reduced their MMP2 enzyme activity and invasiveness about 52.05% in Matrigel assays, and the tumor volumes in nude mice resulted in a 3.3-fold reduction. In addition, direct intratumoral injection of Ad-MMP2AS into pre-existing tumors significantly prevented further expansion of the tumor masses and resulted in a 63.06% reduction in tumor cell growth. CONCLUSION: The recombinant adenovirus with antisense MMP2 can effectively inhibit the invasiveness and growth of Bel-7402 cells in vitro and in vivo, and it has a therapeutic potential for HCC.

Adenoviridae↗
PubMed2005

[Construction of recombinant adeno-associated virus vectors carrying double gene of antisense multidrug resistance-associated protein and antisense multidrug resistance].

OBJECTIVE: To construct a recombinant adeno-associated virus vectors carrying double gene of antisense multidrug resistance-associated protein (MRP) and antisense multidrug resistance (MDR1) for use in studying the gene therapy to reverse the multidrug resistance (MDR) in hepatocellular carcinoma (HCC). METHODS: The 500 bp fragment (mrp) of MRP cDNA 5' region and the 600 bp fragment (mdr1) of MDR1 cDNA 5' region were amplified through polymerase chain reaction (PCR), and then they were linked to a combined gene fragment (mrp+mdrl) by overlapping technique. The combined gene fragment(mrp+mdrl) was cloned reversely into the multiple cloning site (MCS) of the expression plasmid pAAV-IRES-hrGFP in AAV Helper-Free System to construct the recombinant expression plasmid pAAV-IRES-hrGFP-(mrp + mdr1)AS. The packaging cell line (HEK 293 cell) was co-transfected with the pAAV-IRES-hrGFP-(mrp+mdr1)AS together with the control plasmid pAAV-RC and pHelper in AAV Helper-Free System by means of lipofectamine. The recombinant adeno-associated virus vector : rAAV2-(mrp+mdr1)AS carrying the double gene of antisense multidrug resistance-associated protein (MRP)and antisense multidrug resistance (MDR1) was packaged. Then the viral titer was checked by GFP. RESULTS: The recombinant adeno-associated virus vector : rAAV2-(mrp + mdr1)AS carrying antisense MRP and antisense MDR1 was constructed successfully, the strong green fluorescence was observed in HEK 293 cells under a fluorescence microscope. The viral titer was 2.5 X 10(6) efu/ml. CONCLUSION: The rAAV2-(mrp+mdr1)AS thus constructed could introduce the antisense MRP and antisense MDR1 into the human drug-resistant hepatocellular cell line effectively, which might provide a sound basis for the mechanisms and reversal methods of the multidrug resistance in HCC.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

Poly[iron(II)-di-mu-imidazole-4,5-dicarboxylato-kappa3N3,O4:O5].

In the title compound, [Fe(C(5)H(3)N(2)O(4))(2)](n), each Fe atom lies on a centre of symmetry, in an octahedral coordination environment consisting of two chelate rings [Fe-N = 2.154 (3) A and Fe-O = 2.180 (3) A] and two carboxylate O atoms [Fe-O = 2.111 (2) A] from imidazole-4,5-dicarboxylate ligands. Extensive hydrogen-bonding interactions exist between layers constructed of Fe(4) squares, forming tunnels along the a axis with large voids.

Journal Article↗
PubMed2004

Atypical presentation of spontaneous discitis: case report.

BACKGROUND: Spontaneous discitis is primarily a pediatric illness. Adult patients usually present at an average age of 69 years with a history of diabetes or with a systemic infection. The lumbar spine is the most frequent site of infection (54%), and the cervical is the least at 10%. The causative organisms are most commonly Staphylococcus aureus and beta-hemolytic streptococcus species. Intravenous antibiotics are the mainstays of treatment, and surgical intervention is usually not required. CASE PRESENTATION: A single case observation with an unusual presentation from the statistically typical criterion of discitis is described. CONCLUSIONS: Atypical discitis needs to be considered in the differential diagnoses in the middle-aged and healthy population.

Aged↗
PubMed2004

High levels of unprotected sex with men and women among men who have sex with men: a potential bridge of HIV transmission in Beijing, China.

China is experiencing an emerging HIV epidemic among men who have sex with men (MSM). We investigated sexual risk, risk perception, HIV and condom knowledge, and utilization of prevention services in the first large sample of MSM recruited in Beijing. Four hundred eighty-two MSM were sampled from September 2001 to January 2002. Forty-nine percent of participants reported unprotected anal intercourse with men during the previous 6 months. However, only 15% perceived they are at risk for HIV and many had misconceptions about HIV transmission routes and limited knowledge about condoms. Less than one quarter obtained free condoms (24%) and condom lubricants (19%) in the past 2 years. Multiple logistic regression analysis showed that unprotected insertive anal intercourse was associated with not having a Beijing residence card, having six or more male sexual partners, not having sex with women, having a lifetime history of sexually transmitted diseases (STDs), and having never tested for HIV. Unprotected receptive anal intercourse was independently associated with having six or more male sexual partners, not having sex with women, having a lifetime history of STDs, having never tested for HIV, and having less exposure to HIV prevention services. In addition, 28% reported having sex with both men and women during the previous 6 months, and 11% had unprotected intercourse with both men and women. This finding suggests that MSM are a potential bridge of HIV transmission to heterosexual women (or vice versa) and that addressing the HIV prevention needs of MSM may benefit the wider population.

Adolescent↗
PubMed2004

HIV risk behaviors among male-to-female transgender persons of color in San Francisco.

OBJECTIVES: The authors examined HIV risk behaviors among African American, Asian/Pacific Islander (API), and Latina male-to-female (MTF) transgender persons in order to improve HIV prevention programs. METHODS: Individual survey interviews with MTF transgender persons of color (n = 332; 112 African Americans, 110 Latinas, and 110 APIs) were conducted. RESULTS: Prevalence and correlates of receptive anal sex and unprotected receptive anal sex (URAS) varied by type of partner (primary, casual, or commercial sex partners). URAS with primary partners was associated with drug use before sex; URAS with casual partners was associated with HIV-positive status and drug use before sex; and URAS with commercial sex partners was associated with African American ethnicity and low income. CONCLUSIONS: Findings on current risk behaviors among MTF transgender persons provided meaningful implications for HIV prevention interventions.

Adolescent↗
PubMed2004

Possible horizontal transmission of crimean-congo hemorrhagic Fever virus from a mother to her child.

The case of a child with Crimean-Congo hemorrhagic fever (CCHF) presumably infected with CCHF virus from her 27-year-old mother is described. The mother with CCHF was treated with ribavirin and did not present with any symptoms of obvious hemorrhage. The child developed fever on the 5th day after the mother's onset. The partial virus genome was amplified by RT-PCR, and nested PCR from the child and the genome sequence were identical to that from the mother, indicating possible transmission of the virus from mother to child. This case indicates the importance of preventive measures for in-house outbreaks of CCHF.

Adult↗
PubMed2004

[Effect of different dosage of vitamin A supplement on anti-oxidative activity and the fluidity of erythrocyte membrane in rats].

OBJECTIVE: To investigating the effect of vitamin A (VA)at different dosage of vitamin A on anti-oxidative activity and the fluidity of erythrocyte membrane in rats and safe dosage. METHODS: Wistar rats selected for VA supplement trial were randomly divided into four groups. The first group was no VA supplement as a control, and the second, third, forth groups were daily supplemented with VA 11.43, 42.86 and 142.86 microg RE/kg respectively. The trial lasted 8 weeks. Vitamin A was dissolved in soybean oil and daily given to animals by gavage. The blood samples were collected at the end of the trial. The level of plasma VA was analyzed by fluorescent spectrometry. SOD, GSH and MDA in plasma were analyzed. The blood erythrocyte membrane fluidity was detected by fluorescence polarization method. RESULTS: The results showed that plasma retinol levels increased with increase of vitamin A. After 8 week supplement, SOD activities in the second and the third groups were lower than those of the first and the fourth group (P < 0.01), which was the highest in the four groups (P < 0.01). The level of plasma MDA in the third was the lowest (P 0.01). GSH-Px activity was higher in the third group than other three groups (P < 0.01). Moreover, P (fluorescence polarization) was lower in 42.86 microg RE/kg group than other three groups, and P significantly increased in the fourth group (P < 0.01), which indicates that the erythrocyte membrane fluidity increased significantly after 42.86 microg RE/kg vitamin A supplement. CONCLUSION: The supplement of 42.86 microg RE/kg VA could improve anti-oxidative activity and enhance erythrocyte membrane fluidity. Overtake vitamin A could produce a poisoning effect and a stronger oxidative damage.

Animals↗
PubMed2003

A three-dimensional manganeseII complex exhibiting ferrimagnetic and metamagnetic behaviors.

A three-dimensional complex, [Mn(3)(4-aba)(6)](n) (1) (4-Haba = 4-aminobenzoic acid), consisting of manganese(II) chains and 4-aba bridging ligands, has been synthesized and characterized. Magnetic studies show that the compound behaves as a three-dimensional metamagnet built of homometallic ferrimagnetic chains. The required noncompensation in spin moments is achieved by alternating interactions in an AF-AF-F sequence (AF = antiferromagnetic; F = ferromagnetic) by considering intrachain magnetic interactions.

Journal Article↗