Biomedical subjects

Min Liu

Publications and source records attributed to Min Liu.

171 records · Page 10Linked to original sources

PubMed2002

Microarray analysis of neural stem cell differentiation in the striatum of the fetal rat.

1. Gene expression profiles in neural stem cell differentiation in vitro were determined by cDNA microarray analysis. 2. Total RNA was extracted and reverse transcripted into cDNA from differentiated and undifferentiated neural stem cells. The 33P labeled cDNA was hybridized with a cDNA microarray consisting of 14,000 human genes. 3. The results showed that a total of 1406 genes were differentially expressed, of which 148 genes exhibited more than twofold differences. Some genes were obviously activated while others were strongly repressed. These changes in gene expression suggest that differentiation is regulated by different genes at different expressional levels. By biological classification, the differentially expressed genes were divided into four functional categories: molecular function, biological process, cellular component, and new functional genes or ESTs. 4. These findings will be a valuable contribution for gene expression profiling and elucidation of neural stem cell differentiation mechanisms.

Animals↗

PubMed2002

The study of nafion/xanthine oxidase/au colloid chemically modified biosensor and its application in the determination of hypoxanthine in myocardial cells in vivo.

A novel hypoxanthine (Hx) microsensor was constructed. In this work, Nafion xanthine oxidase (XOD) and Au colloid were immobilized onto the surface of a Pt microelectrode. The enzyme biosensor displayed a quick and sensitive response to Hx. Under physiological conditions, a low detection limit, with high selectivity and sensitivity for Hx determination were obtained. The oxidation current [investigated using current-time (I-t) plots] was linear with Hx concentration ranging from 2.0 x 10(-7) to 2.0 x 10(-5) mol L(-1) with a calculated detection limit of 1.0 x 10(-7) mol L(-1) (S/N of 3). The biosensor should be promising for in vivo measurement of Hx without interferences and fouling. The change of Hx concentration in cardiac myocytes stimulated by L-arginine (L-Arg) and acetylcholine (Ach) was also studied.

Biosensing Techniques↗

PubMed2002

[Establishment of an indirect enzyme-linked immunosorbent assay for detecting the specific IgM antibodies in patients with echovirus infection].

BACKGROUND: To provide a simple, specific and early serodiagnostic technique for the patients with aseptic meningitis caused by echovirus. METHODS: An indirect enzyme-linked immunosorbent assay (ELISA) has been developed to detect echovirus-IgM and the specificity and availability of the assay were also examined. RESULTS: In 78 cerebrospinal fluid (CSF) specimens which came from the children with aseptic meningitis, the positive rate was 17.9(14/78). In 64 CSF collected from non-aseptic meningitis (bacterial meningitis and cerebral trauma), the positive rate was 1.56(1/64). In 5 CSF specimens which were ELISA positive, the positive rate of neutralization test (NT) was 4/5, all the specimens which were ELISA negative were NT negative. In this assay there was no cross-reaction with poliovirus, Coxsackie virus B type 1-6 and A type 7. By blocking and destructive test of specific IgM, all CSF specimens with ELISA positive became negative. CONCLUSIONS: The established indirect ELISA was specific and reliable. The te st was quick, simple and available, which is suitable for early and specific clinical diagnosis, and will be greatly significant to clinical treatment.

Adult↗

PubMed2002

Effects of simulated microgravity on characteristics of photosynthesis in plant seedling.

OBJECTIVE: To study the effects of simulated microgravity on the characteristics of photosynthesis in some plant seedlings. METHOD: Plant samples were treated on a 1 pi clinostat rotated at 2 gamma/min for 120 h. Then chlorophyll absorption and chlorophyll fast fluorescence induction kinetics were determined. RESULT: After treatment on the clinostat: 1) there were some increase in height and number of leaves per plant; 2) the strawberry seedlings contained 47.5% less chlorophyll and the carnation seedlings contained 4.3% more; 3) there was no change in position of the main absorption peaks of chlorophyll in both seedlings after the rotation, but their intensity was increased; 4) there were significant increase in the parameters of fluorescence induction kinetics in the leaves of both seedlings: there was an increase in Fv/Fo, Fv/Fm and T1/2, except CA/Fo; 5) there were some differences in excitation energy distribution between the two photosystems in the chloroplasts of control and treated samples. CONCLUSION: Simulated microgravity does not have a significant effect on normal photosynthetic function in chloroplasts, so plant seedlings can grow up normally under microgravity.

Chlorophyll↗

PubMed2002

[Cloning and expression of HSV-I, II type-common antigen gD in Escherichia coli].

BACKGROUND: To clone the type common antigen gD of human herpes simplex virus I, II (HSV-I, II), the authors constructed recombinant expression vector Pmal-c2/gD and induced to express the fusion protein MBP-gD. METHODS: The authors extracted HSV DNA,amplified gD gene by PCR assay and directly cloned it into prokaryotic expression vector pMAL-c2, then transformed it into E.coli DH5alpha. After proved to be correct by PCR, double enzyme digestion and sequencing, the fusion protein is induced to express by IPTG and detected by both Western blot and ELISA. RESULTS: The constructed expression vector pMAL-c2/gD can be expressed with high efficiency. The product expressed was about 35.5% of the total bacterium proteins by SDS?PAGE analysis and was found nearly 39% as soluble protein,61% as inclusion in cytoplasm. CONCLUSIONS: The authors constructed recombinant expression vector pMAL-c2/gD, the Western blotting result showed that the recombinant protein could be identified with gD specific monoclonal antibody DL6. Therefore the protein was of natural antigenic structure of gD.

Cloning, Molecular↗

PubMed2002

[Research progress in space plant breeding].

A brief introduction of the advances in study of space mutation of plants is given in this article. It includes: factors influencing plants in space flight, different levels of biological effects of space mutation and researches on space mutation breeding. Prospects are also put forward in this article.

Mutation↗

PubMed2002

[Effect of Salvia miltiorrhiza on autocrining growth factor by fibroblasts cultured in vitro].

OBJECTIVE: To investigate the mechanism of overhealing alleviation by salvia miltiorrhiza (SM) in wound healing. METHODS: Fibroblasts were cultured in vitro, and SM was applied with different concentrations (40, 80, 160 and 320 micrograms/ml) and time(the 1st, 2nd, 3rd, 4th and 5th days) to influence their autocrine. The levels of transforming growth factor-beta 1 (TGF-beta 1) and epidermal growth factor (EGF) were determined by ELIAS and radioimmunoassay respectively. RESULTS: The SM could inhibit autocrine of TGF-beta 1 by fibroblasts (P < 0.05). However, it did not affect autocrine of EGF (P > 0.05). CONCLUSION: The above results indicate that SM reduces overhealing by inhibiting the autocrine of TGF-beta 1 selectively.

Cell Division↗

PubMed2002

[An epidemiological survey on reproductive track infection and the investigation on syndromic approach on vaginal discharge].

OBJECTIVE: To investigate the reproductive track infection (RTI) situation and risk factors for cervical infection (Neisseria gonorrhoeae or Chlamydia trachomatis) among different kinds of women of childbearing age in Shenzhen city, China. To assess the feasibility of the syndromic approach for vaginal discharge. METHODS: The survey was administrated to 4,744 eligible women in Shenzhen city during October 2001 and April 2002. The subjects included three different kinds of population: 3,895 cases of general population, 438 STD/gynecological clinic outpatients and 411 people with high risk behavior. Gynaecologic examination and RTI laboratory diagnosis were performed for each subject. PCR method-based test was used to detect the Neisseria gonorrhoeae and Chlamydia trachomatis infection. Standardized questionnaire were designed to collect the information about RTI related behaviors, and history of marriage and child bearing, et al. The risk factors, symptoms and signs of cervical infection were analyzed. Syndromic approach was established and its feasibility was assessed. RESULTS: 27.6% of women in Shenzhen were infected with at least one kind of RTI, including 5.0% with cervical infection. The risk factors for cervical infection were: individuals having had new sex partner within last 3 months (OR = 1.6, 95% CI: 1.1 - 2.4), having had the experience of abortion (OR = 1.6, 95% CI: 1.1 - 2.4), aged 25 or less (OR = 1.6, 95% CI: 1.1 - 2.4) and never using condom during sex intercourse (OR = 1.7, 95% CI: 1.1 - 2.4). The sensitivity of syndromic approach of risk assessment and signs for cervical infection among general population was 63.8%, while specificity was 55.1% with the positive predictive value 7.0%. CONCLUSIONS: RTI infection was common among all three kinds of childbearing women in Shenzhen city. The prevalence of RTI was the highest among high risk population, followed by STD/gynecological clinic outpatients. The efficacy of syndromic approach for cervical infection in general population was not ideal.

China↗

PubMedDate not supplied

Synthesis and biological evaluation of diethylenetriamine pentaacetic acid-polyethylene glycol-folate: a new folate-derived, (99m)Tc-based radiopharmaceutical.

(99m)Technetium-labeled diethylenetriamine pentaacetic acid-polyethylene glycol-folate (DTPA-PEG-folate) was synthesized and tested as a radiopharmaceutical agent, which targeted the lymphatic system with metastatic tumor. Folic acid was reacted with H2N-PEG-NH2 to yield H2N-PEG-folate. After purification by anion-exchange chromatography, the product was reacted with cyclic DTPA. By removal of unreacted DTPA by size-exclusion chromatography, DTPA-PEG-Folate was obtained. Fluorescein-5-isothiocyanate (FITC)-labeled DTPA-PEG-folate and DTPA-PEG-OCH3 were prepared via a dicyclohexylcarbodiimide-mediated coupling. In vitro competitive binding test showed that the uptake of [125I] folic acid was inhibited by DTPA-PEG-folate and the 50% inhibitory concentration was 4.37 pmol/L (R2 = 0.9922). The relative affinity of DTPA-PEG-FITC was 0.18 for human folate receptor comparing with folic acid. In cultured tumor cells, uptake of fluorescence-labeled DTPA-PEG-folate was found to increase significantly in folate-deficient medium compared with that of untargeted DTPA-PEG-OCH3 and FITC-ethylenediamine. The competition with free folic acid blocked the cell uptake of DTPA-PEG-folate. These results confirmed the DTPA-PEG-folate entered into KB cells through the folate receptor endocytosis pathway in vitro. The radiolabeled yield of [(99m)Tc] DTPA-PEG-folate was in excess of 98%, and specific activities of 7.4 kBq (0.2 microCi/microg) were achieved. After subcutaneous injection, [(99m)Tc] DTPA-PEG-folate exhibited an initial increase and successive decline of accumulation in popliteal nodes in normal Wistar rats. Expect for the kidney, uptake by other tissues was rather low. In a normal rabbit imagine study, the lymphatic vessels were readily visualized by single-photon-emission computed tomography following subcutaneous injection of [(99m)Tc] DTPA-PEG-folate. In conclusion, the [(99m)Tc] DTPA-PEG-folate conjugate may have a potential as a lymphatic tumor-targeted radiopharmaceutical.

Animals↗