Biomedical subjects

Min He

Publications and source records attributed to Min He.

47 records · Page 3Linked to original sources

PubMed2003

[Study on lung carcinogenesis associated genes in human lung squamous cell carcinoma and malignant transformation of human bronchial epithelial cells induced by carcinogen].

OBJECTIVE: To investigate lung carcinogenesis associated genes in human lung squamous cell carcinoma and malignant transformation of human bronchial epithelial cells induced by chemical carcinogens with cDNA microarray. METHODS: The gene expression patterns were detected in all specimens by cDNA microarray which representing 4 096 different human genes. The differences in gene expression among 6 cases of human lung squamous cell carcinoma tissues and 6 normal lung tissues were analyzed. The different gene expression patterns between the normal human bronchial epithelial cell lines (16HBE) and the malignant transformation of human bronchial epithelial cells induced by Benzo(a)pyrene metabolite BPDE (anti-Benzo(a)pyrene diol-epoxide,BPDE) and crystalline nickel sulfide were also studied by that method. The similar changed genes among those gene expression patterns were identified as lung carcinogenesis associated genes. RESULTS: Among the 4096 genes of cDNA microarrays, there were 171 genes expressed differently among lung cancer tissues and normal lungs, 143 genes expressed differently between BPDE transformed cells and normal 16HBE cell lines, 151 genes differed between nickel sulfide transformed cells and normal 16HBE cell lines. By comparing the gene expression profiles, there were 89 similar changed genes which might be associated with human lung carcinogenesis, 39 of which were up regulated: 6 oncogenes, 4 cell cycle control genes, 6 cell proliferation genes, 8 metastasis genes, 3 neuroendocrine genes, 1 drug-resister gene, 1 anti-apoptosis gene, 1 oxidative gene and other 9 genes. 50 genes were down-regulated: 7 tumor suppression genes, 11 DNA repair genes, 1 antioxidant genes, 3 GST family genes, 3 cell framework genes, 2 apoptosis induced genes, 5 signal conduction genes, 5 cytokines and their receptor genes, 7 metabolization genes, 1 cell matrix genes, and other 5 genes. CONCLUSION: cDNA microarray can be applied to study gene expression profiles effectively and to screen human lung carcinogenesis associated genes.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed2003

Two ion/ion charge inversion steps to form a doubly protonated peptide from a singly protonated peptide in the gas phase.

An approach is described to increase the degree of protonation of a polypeptide ion in the gas phase. Sequential charge inversion reactions involving the reactions of oppositely charged ions are used to yield a net increase in ion charge. The approach is illustrated here with the conversion of singly protonated bradykinin to doubly protonated bradykinin. The first step involves conversion of the singly protonated peptide to the singly deprotonated peptide via reactions with multiply charged anions derived from carboxylate-terminated dendrimers. Some of the singly deprotonated peptide was then converted to doubly protonated peptide via reactions with multiply charged cations derived from amino-terminated dendrimers. The overall approach is illustrative of a general strategy for increasing the absolute charge states of large ions in the gas phase.

Anions↗

PubMed2003

[Identification of Mycobacterium tuberculosis and rifampin-resistant strains by gene-chips].

OBJECTIVE: To evaluate the gene-chip detecting rifaman-resistance Mycobacterium tuberculosis applied in TB diagnosis and drug-resistant detection. METHODS: Mycobacterium tuberculosis and rifaman-resistant strains among 35 rifaman-resistance isolated strains and 102 sputa specimens from TB patients, 27 sputa specimens from other patients were examined the gene-chips. Results obtained were compared with sputum examination, bacteriological culture and standard drug susceptibility test of Mycobacterium tuberculosis. RESULTS: Thirty-five rifaman-resistance strains were detected by gene-chips and 33 were identified as rifaman-resistance strains and the concordance with the traditional drug susceptibility test of Mycobacterium tuberculosis was 94.29%. Twenty-seven sputa specimens from other patients were examined Mycobacterium tuberculosis by the gene-chips, 2 were positive, the detection specialty was 92.59%. Using three methods detecting Mycobacterium tuberculosis among 102 sputa specimens the positive rate respectively was, sputum examination 35.29% (36/102), bacteriological culture 28.43% (29/102), gene-chip 77.45% (79/102). Among 102 sputa specimens only 29 examined Mycobacterium tuberculosis by the traditional drug susceptibility test and 8 were rifaman-resistant strains. While using gene-chip, there were 20 among 102 sputa specimens identified as rifaman-resistance strains. Among total 55 rifaman-resistance strains detected by the gene-chips, the most frequent mutations were those associated with codon 531 (23 of 55; 41.8%), 526 (15 of 55; 27.27%) and 516 (9 of 55; 16.36%). CONCLUSION: Results showed that this was a rapid, simple and highly specific method when using gene-chip to detect Mycobacterium tuberculosis and rifaman-resistant strains.

China↗

PubMed2002

Dissociation of multiple protein ion charge states following a single gas-phase purification and concentration procedure.

The formation of a range of precursor ion charge states from a single concentrated and purified charge state, followed by activation of each charge state, is introduced as a means to obtain more protein structural information than is available from dissociation of a single charge state alone. This approach is illustrated using off-resonance collisional activation of the [M + 8H]8+ to [M + 6H]6+ precursor ions of the bacteriophage MS2 viral coat protein following concentration and purification of the [M + 8H]8+ charge state. This range of charge states was selected on the basis of an ion trap collisional activation study of the effects of precursor ion charge state on the dissociation of the [M + 12H]12+ to [M + 5H]5+ ions. Gas-phase ion/ion proton-transfer reactions and the ion parking technique were applied to purify and concentrate selected precursor ion charge states as well as to simplify the product ion spectra. The high-charge-state ions fragment preferentially at the N-terminal side of proline residues while the product ion spectra of the lowest charge states investigated are dominated by C-terminal aspartic acid cleavages. Maximum structural information is obtained by fragmentation of the intermediate-charge states.

Amino Acid Sequence↗

PubMed2002

Molecular basis of mitomycin C resistance in streptomyces: structure and function of the MRD protein.

Mitomycin C (MC) is a potent anticancer agent. Streptomyces lavendulae, which produces MC, protects itself from the lethal effects of the drug by expressing several resistance proteins. One of them (MRD) binds MC and functions as a drug exporter. We report the crystal structure of MRD and its complex with an MC metabolite, 1,2-cis-1-hydroxy-2,7-diaminomitosene, at 1.5 A resolution. The drug is sandwiched by pi-stacking interactions of His-38 and Trp-108. MRD is a dimer. The betaalphabetabetabeta fold of the MRD molecule is reminiscent of methylmalonyl-CoA epimerase, bleomycin resistance proteins, glyoxalase I, and extradiol dioxygenases. The location of the binding site is identical to the ones in evolutionarily related enzymes, suggesting that the protein may have been recruited from a different metabolic pathway.

Amino Acid Sequence↗

PubMed2002

Sequential changes of hypoxia-inducible factor 1 alpha in experimental spinal cord injury and its significance.

OBJECTIVE: To study the sequential changes of HIF-1alpha (hypoxia-inducible factor 1 alpha) in experimental spinal cord injury in rats and to analyze its potential effects in SCI. METHODS: A static compression model of SCI was employed in this study. Expressions of HIF-1alpha were measured with immunohistochemical staining, while flow cytometry was used to determine the apoptotic ratio and bcl-2 expressions. RESULTS: HIF-1alpha began to increase 1 day after injury, and reached the peak at 3-7 days. Two weeks later, it declined significantly. The sequential changes of HIF-1alpha coincided well with the alterations of apoptotic ratio and contents of bcl-2. CONCLUSIONS: HIF-1alpha possibly participates in the secondary ischemic and hypoxic procedures after spinal cord injury, and may mediate the traumatic apoptosis. Further understanding of HIF-1alpha may provide new therapeutic regimens for SCI.

Animals↗

PubMed2002

Bioluminescent method for detecting telomerase activity.

BACKGROUND: Telomerase is a promising biomarker in cancer diagnosis and therapy. The elongation of telomeric repeats catalyzed by telomerase is accompanied by release of six PP(i) for each TTAGGG repeat (1 pmol PP(i)/310 pg telomeric repeats). We developed a novel method to measure telomerase activity by use of an enzymatic luminometric PP(i) assay (ELIPA). METHODS: Extracts of cell lines and tissues were incubated with primer at 30 degrees C for 30 min. Released PP(i) was converted to ATP by sulfurylase, and ATP was detected by a luciferase bioluminescence system. The ELIPA results were compared with results obtained with the conventional telomeric repeat amplification (TRAP)-ELISA in 42 lung carcinoma tissues and 27 control tissues without malignancy. RESULTS: The lower detection limits of ELIPA and TRAP-ELISA were 5 and 10 cells, respectively. The within-run imprecision (CV) of ELIPA was < or =12%. When compared with TRAP-ELISA, the correlation coefficient (r) was 0.79. When we used the cutoff value from ROC analysis to distinguish malignant and nonmalignant tissues, the sensitivity and specificity of ELIPA were 83% and 96%, respectively, whereas the sensitivity and specificity of TRAP-ELISA were 71% and 96%, respectively. CONCLUSION: ELIPA is a simple and sensitive homogeneous method to quantify telomerase activity.

Adenosine Triphosphate↗

PubMed2002

[Study on expression of beta-NGF in myoblasts transfected by PSVCEP NGF-CAT with Lipofect AMINE].

OBJECTIVE: To gain an understanding of the expression of beta-NGF in myoblasts transfected by PSVCEP NGF-CAT and the transfecting efficiency of Lipofect AMINE. METHODS: PSVCEP NGF-CAT was delivered into cultured myoblasts by Lipofect AMINE. Expression of beta-NGF in the transfected myoblasts was detected by immunocytochemistry. RESULTS: Lipofect AMINE was evidently engulfed by myoblasts at the 6th hour; about 40% myoblasts could be detected with the expression of beta-NGF by immunocytochemistry at the 48th hour. CONCLUSION: PSVCEP NGF-CAT can express beta-NGF in cultured myoblasts, and Lipofect AMINE is a convenient vector for gene transfection with simplicity and efficacy.

Animals↗

PubMed2002

[Sequential changes of hypoxia-inducible factor 1 alpha in experimental spinal cord injury and its significance].

OBJECTIVE: To investigate the sequential changes of hypoxia-inducible factor 1 alpha (HIF-1 alpha) in experimental spinal cord(SCI) injury in rats and analyze its potential effects on SCI. METHODS: Static compression model of SCI was employed in this study. Expressions of HIF-1 alpha were measured with immunohistochemical staining. Flow cytometry was used to determine the apoptotic ratio and bcl-2 expressions. RESULTS: HIF-1 alpha began to increase one day after injury, and reached peak at 3-7 days. Two weeks later, it declined significantly. The sequential changes of HIF-1 alpha coincided well with the alterations of apoptotic ratio and bcl-2 content. CONCLUSION: HIF-1 alpha may participate in the secondary ischemic and hypoxic procedures after spinal cord injury and mediate the traumatic apoptosis. Further understanding of HIF-1 alpha may provide new therapeutic regimens for SCI.

Animals↗

PubMed2002

[Incidence, mortality and survival rates of female breast cancer in Tianjin, China].

OBJECTIVE: To observe the trend in the change of incidence and mortality of female breast cancer in Tianjin and evaluate its effect of prevention. METHODS: Method of descriptive epidemiology was used to study the epidemic situation of female breast cancer in Tianjin. RESULTS: The incidence of breast cancer in Tianjin had increased by 39.7% from 1981 to 1997, as compared with the other cities in China. Especially, compared with the developed countries the world over, the incidence of breast cancer in Tianjin is much lower. The mortality rate of breast cancer had lowered by 31.0% from 1981 to 1997 and the 3-year and 5-year survival rates increased to various degrees. CONCLUSION: Early detection and diagnosis of breast cancer are very important to both increase of survival and lowering of mortality of breast cancer. Preventive efforts should be made to the high risk people of breast cancer.

Adult↗

PubMed2000

Study on neuronal apoptosis induced by hypoxia or traumatic injury in rats.

OBJECTIVE: To explore the relationship between neuronal apoptosis and hypoxia or traumatic injury. METHODS: Rat neurons primarily cultured in vitro were treated w ith hypoxia (the hypoxia group) or traumatic injury (the trauma group). The neur onal apoptosis was evaluated with microscope, TUNEL (terminal deoxynucleotidyl t ransferase mediated X-dUTPnick end labeling) staining, flow cytometry, agarose gel electrophoresis and immunohistochemistry RESULTS: Morphological changes of apoptosis appeared in the t reated neurons and the DNA fragmentation showed "ladder" break. The apoptotic index was 10.8% in the hypoxia group and 4.8% in the trauma group, while it was only 1.6% in the control group. The expression of apoptosis-associated genes (c-myc, fas and fasL) increased. CONCLUSIONS: Hypoxia or traumatic injury can induce neuronal ap optosis, and its molecular mechanism is probably related to the expressions of a poptosis-associated genes.

Journal Article↗