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Hong Liang

Publications and source records attributed to Hong Liang.

70 records · Page 4Linked to original sources
PubMed2002

Functional profiling of the Saccharomyces cerevisiae genome.

Determining the effect of gene deletion is a fundamental approach to understanding gene function. Conventional genetic screens exhibit biases, and genes contributing to a phenotype are often missed. We systematically constructed a nearly complete collection of gene-deletion mutants (96% of annotated open reading frames, or ORFs) of the yeast Saccharomyces cerevisiae. DNA sequences dubbed 'molecular bar codes' uniquely identify each strain, enabling their growth to be analysed in parallel and the fitness contribution of each gene to be quantitatively assessed by hybridization to high-density oligonucleotide arrays. We show that previously known and new genes are necessary for optimal growth under six well-studied conditions: high salt, sorbitol, galactose, pH 8, minimal medium and nystatin treatment. Less than 7% of genes that exhibit a significant increase in messenger RNA expression are also required for optimal growth in four of the tested conditions. Our results validate the yeast gene-deletion collection as a valuable resource for functional genomics.

Cell Size↗
PubMed2002

A human Mix-like homeobox gene MIXL shows functional similarity to Xenopus Mix.1.

Molecular events involved in specification of early hematopoietic system are not well known. In Xenopus, a paired-box homeodomain family (Mix.1-4) has been implicated in this process. Although Mix-like homeobox genes have been isolated from chicken (CMIX) and mice (Mml/MIXL1), isolation of a human Mix-like gene has remained elusive. We have recently isolated and characterized a novel human Mix-like homeobox gene with a predicted open reading frame of 232 amino acids designated the Mix.1 homeobox (Xenopus laevis)-like gene (MIXL). The overall identity of this novel protein to CMIX and Mml/MIXL1 is 41% and 69%, respectively. However, the identity in the homeodomain is 66% to that of Xenopus Mix.1, 79% to that of CMIX, and 94% to that of Mml/MIXL1. In normal hematopoiesis, MIXL expression appears to be restricted to immature B- and T-lymphoid cells. Several acute leukemic cell lines of B, T, and myeloid lineage express MIXL suggesting a survival/block in differentiation advantage. Furthermore, Xenopus animal cap assay revealed that MIXL could induce expression of the alpha-globin gene, suggesting a functional conservation of the homeodomain. Isolation of the MIXL gene is the first step toward understanding novel regulatory circuits in early hematopoietic differentiation and malignant transformation.

Animals↗
PubMed2002

Spectral studies of the binding of lucigenin, a bisacridinium derivative, with double-helix DNA.

The non-covalent binding of the cationic reagent lucigenin to DNA has been investigated by spectroscopic methods. Results from absorption, circular dichroism, and fluorescence studies revealed that lucigenin could intercalate into the helix of DNA. Polarization and melting studies provided further evidence of the intercalation binding of lucigenin with DNA. The binding constant was obtained by varying the DNA concentration while keeping the concentration of lucigenin constant. It was of the order of 10(4) mol(-1) L in DNA base pairs. The experiment also showed that electrostatic interaction played a significant role in the intercalation of lucigenin with DNA. It is suggested that lucigenin can be intercalated into the interior of the DNA double helix because it is initially attracted by the anionic DNA. This research offers a new intercalation functional group for DNA-targeted drug design.

Acridines↗
PubMed2002

Effects of enhanced external counterpulsation on stress radionuclide coronary perfusion and exercise capacity in chronic stable angina pectoris.

Enhanced external counterpulsation (EECP) is an effective noninvasive treatment for patients with coronary artery disease (CAD). EECP has been demonstrated to improve anginal class and time to ST-segment depression during exercise stress testing. This study assesses the efficacy of EECP in improving stress-induced myocardial ischemia using radionuclide perfusion treadmill stress tests (RPSTs). The international study group enrolled patients from 7 centers with chronic stable angina pectoris and a baseline ischemic pre-EECP RPST. Patients' demographic and clinical characteristics were recorded. A baseline pre-EECP maximal RPST was performed within 1 month before EECP treatment. The results were compared with a follow-up RPST performed within 6 months of completion of a 35-hour course of EECP. Four centers performed post-EECP RPST to the same level of exercise as pre-EECP, whereas 3 centers performed maximal RPST post-EECP. The study enrolled 175 patients (155 men and 20 women). Improvement in angina, defined by > or =1 Canadian Cardiovascular Society angina class change, was reported in 85% of patients. In the centers performing the same level of exercise, 81 of 97 patients (83%) had significant improvement in RPST perfusion images. Patients who underwent maximal RPST revealed improvement in exercise duration (6.61 +/- 1.88 pre-EECP vs 7.41 +/- 2.03 minutes post-EECP, p <0.0001); 42 of the 78 patients (54%) in this group showed significant improvement in RPST perfusion images. Thus, EECP was effective in improving stress myocardial perfusion in patients with chronic stable angina at both comparable (baseline) and at maximal exercise levels.

Aged↗
PubMed2002

A novel, evolutionarily conserved gene family with putative sequence-specific single-stranded DNA-binding activity.

Complete and partial deletions of chromosome 5q are recurrent cytogenetic anomalies associated with aggressive myeloid malignancies. Earlier, we identified an approximately 1.5-Mb region of loss at 5q13.3 between the loci D5S672 and D5S620 in primary leukemic blasts. A leukemic cell line, ML3, is diploid for all of chromosome 5, except for an inversion-coupled translocation within the D5S672-D5S620 interval. Here, we report the development of a bacterial artificial chromosome (BAC) contig to define the breakpoint and the identification of a novel gene SSBP2, the target of disruption in ML3 cells. A preliminary evaluation of SSBP2 as a tumor suppressor gene in primary leukemic blasts and cell lines suggests that the remaining allele does not undergo intragenic mutations. SSBP2 is one of three members of a closely related, evolutionarily conserved, and ubiquitously expressed gene family. SSBP3 is the human ortholog of a chicken gene, CSDP, that encodes a sequence-specific single-stranded DNA-binding protein. SSBP3 localizes to chromosome 1p31.3, and the third member, SSBP4, maps to chromosome 19p13.1. Chromosomal localization and the putative single-stranded DNA-binding activity suggest that all three members of this family are capable of potential tumor suppressor activity by gene dosage or other epigenetic mechanisms.

Amino Acid Sequence↗
PubMed2002

Study on the screening of molecular structure parameter in QSAR model.

Based on the analysis of information flow through the Artificial Neural Network (ANN), a new screening rule of the molecular structure parameter in Quantitative Structure-Activity Relationship (QSAR) was presented by comparing of the values of connection weights and biases of the ANN model. The result showed that model quality and prediction ability of QSAR model, which was constructed by screening structural parameter with ANN, were better than by the method with MLR. The method established the foundation for further study in the mechanism research of the bio-toxicity of organic chemicals.

Animals↗
PubMed2002

Effects of benzyl isothiocyanate and phenethyl isothiocyanate on DNA adduct formation by a mixture of benzo[a]pyrene and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in A/J mouse lung.

Dietary phenethyl isothiocyanate (PEITC) and a mixture of dietary PEITC and benzyl isothiocyanate (BITC) inhibit lung tumorigenesis in A/J mice induced by a mixture of the tobacco smoke carcinogens benzo[a]pyrene (B[a]P) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In this study, we tested the hypothesis that inhibition of tumorigenesis by these isothiocyanates was due to inhibition of DNA adduct formation. We quantified the following pulmonary DNA adducts: N2-[7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene-10-yl]deoxyguanosine (BPDE-N2-dG) from B[a]P; and O(6)-methylguanine (O(6)-mG) and 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB)-releasing adducts from NNK. Initial experiments demonstrated that there were no effects of B[a]P on NNK-DNA adduct formation, or vice versa, and established by way of a time course study the appropriate sacrifice intervals for the main experiment. Dietary PEITC, or dietary BITC plus PEITC, inhibited the formation of HPB-releasing DNA adducts of NNK at several of the time points examined. There were no effects of dietary isothiocyanates on levels of O(6)-mG or BPDE-N2-dG. These results, which are consistent with previous studies in rats and with tumor inhibition data in mice, support a role for inhibition of HPB-releasing DNA adducts of NNK as a mechanism of inhibition of tumorigenesis by dietary PEITC and BITC plus PEITC. However, the observed inhibition was modest, suggesting that other effects of isothiocyanates are also involved in chemoprevention in this model.

Animals↗
PubMed2002

[The application of sodium hyaluronate in joint diseases].

OBJECTIVE: To review the physiological function of sodium hyaluronate in joints and its clinical applications. METHODS: Many literatures were reviewed and analysed on therapeutic mechanism and the application foreground of sodium hyaluronate. RESULTS: Extrinsic sodium hyaluronate plays an important role in improving synovial fluid and protecting cartilages as well as suppressing inflammation, so it is used in the treatment of joint diseases such as knee osteoarthritis, rheumatoid arthritis or temporomandibular osteoarthritis. CONCLUSION: Sodium hyaluronate possesses a good applied prospect in joint diseases.

Arthritis, Rheumatoid↗
PubMed2002

[The quantitative measurement of several main contaminants in sealed cabin].

OBJECTIVE: To establish a standardized analytical method of chromatography used for separating and determining six target contaminants including methyl alcohol, ethanol, glycol, acetic acid, acetone and benzene in space cabin simultaneously. METHOD: Optimal separating and examining conditions were determined through experiments by gas chromatography. Retention time was used to determine the nature of contamination and the method of extended standard to quantify accurately the six mixed contaminants. The method of five-point calibration was used. RESULT: Non-polar capillary GC column (30.00 m x 0.25 micrometers x 250 micrometers) was selected. Oven temperature was -30 degrees C initially and then hoisted to 80 degrees C at a rate of 4 degrees C/min, to 150 degrees C at 6 degrees C/min, to 250 degrees C at 10 degrees C/min and kept for 5 min. The temperature of flame ionization detector was 200 degrees C and that of back inlet adopting split mode was 150 degrees C. The linear correlation of calibration curve was satisfied and the precision of this method was high. CONCLUSION: Under optimal experimental conditions the chromatographic peaks of six contaminants were separated so completely that they were quantified accurately simultaneously. The results showed this method was simple, quick and accurate.

Air Pollutants↗
PubMed2002

[DNA chip technology and its application in toxicology [correction of toxiology]].

DNA chip is a new molecular biology technology rapidly developed in recent years. It fixes thousands of oligonucleotide on a silicon chip of 1 cm2, hybridizes the measuring materials marked with fluorescein or isotope with probe in DNA chip, and gets the fluorescent signal of hybridized probe through the scan of confocalmicroscope. This technology has been extensively used in HGP, DNA sequencing, transcript analysis, gene diagnosis etc. Toxicology is an important branch of life science. DNA chip can be extensively used in the toxicological [correction of toxiological] field. This paper reviewed the DNA chip technology in mechanism, manufacturing method, signal check, advantages and application prospect in toxicology.

Aerospace Medicine↗
PubMed2002

Effect of TiO2 surface properties on the SCR activity of NOx emission abatement catalyst.

NOx emission abatement catalysts V2O5 supported on various TiO2 including anatase, rutile and mixture of both were investigated with various physico-chemical measurements such as BET, NH3-TPD, NARP, XRD and so on, and the effect of TiO2 surface properties on the SCR (selective catalytic reduction) activity of V2O5/TiO2 catalysts was studied. It was found that the TiO2 surface properties had strong effect on the SCR activity of V2O5/TiO2 catalysts. The stronger acidic property resulted in the higher exposure of active sites as well as the higher SCR activity.

Air Pollutants↗
PubMed2002

[Studies on chemical constituents in the root of Hedysarum polybotrys].

OBJECTIVE: To study the chemical constituents in the root of Hedysarum polybotrys Hand.-Mazz.. METHOD: The constituents were isolated by Sephadex LH-20 and silica gel column chromatography, and their structures were identified on the basis of spectral analysis. RESULT: Five compounds, medicarpin (I), 3-hydroxy-9-methoxycoumestan (II), 3, 9-dihydroxycoumestan (III), beta-sitosterol (IV), beta-sitosterol-3-O-beta-D-glucoside (V) were obtained. CONCLUSION: Compounds II, III, V were obtained from the plant for the first time.

Fabaceae↗
PubMedDate not supplied

The Shanghai case: A qualitative evaluation of community health reform in response to the challenge of population ageing.

Shanghai's health care system is facing a serious challenge of an ageing population, as 14% of its 17 million residents are 65 or older. In 2000, a community health reform was implemented to provide comprehensive and continuous primary care to community residents with a focus on seniors. The study employed the theoretical framework of examining primary care in terms of the constellation of its four unique elements (first contact, comprehensiveness, longitudinality and coordination) and three healthcare components (structure, process and outcome). The study aimed to evaluate the extent to which the reform has achieved its process goals and how the organizational context influenced the level of implementation. In-depth interviews with 25 health providers, 15 seniors and four community leaders were carried out. The study found that the Shanghai community health reform has improved the structure and process of primary care regarding first contact, comprehensiveness and longitunality. However, the reform is constrained by structural barriers on seniors' financial access to resources and the capacity of primary care providers. The previous organization system also constrains the reform in CHCs financing and administration. The Shanghai case illustrates that a broad societal view has to be taken when analysing health reforms, which requires the involvement of multiple sectors including the government, health providers and health consumers.

Aged↗
PubMedDate not supplied

A structure-based 3D-QSAR study of anthrapyrazole analogues of the anticancer agents losoxantrone and piroxantrone.

A series of 13 anthrapyrazole compounds that are analogues of piroxantrone and losoxantrone were synthesized, and their cell growth inhibitory effects, DNA binding, topoisomerase IIalpha mediated (EC 5.99.1.3) cleavage of DNA, and inhibition of DNA topoisomerase IIalpha decatenation catalytic activities were determined. Cell growth inhibitory activity was well-correlated with DNA binding, suggesting that these compounds may act by targeting DNA. However, cell growth inhibition was not well-correlated with the inhibition of topoisomerase IIalpha catalytic activity, suggesting that these anthrapyrazoles did not act solely by inhibiting the catalytic activity of topoisomerase II. Most of the analogues were able to induce DNA cleavage, and thus, it was concluded that they acted, at least in part, as topoisomerase II poisons. Structure-based three-dimensional quantitative structure-activity analyses (3D-QSAR) were carried out on the aligned structures of the anthrapyrazoles docked into DNA using comparative molecular field analysis (CoMFA) and comparative molecular similarity index (CoMSIA) analyses in order to determine the structural features responsible for their activity. Both CoMFA and CoMSIA yielded statistically significant models upon partial least-squares analyses. The 3D-QSAR analyses showed that hydrogen-bond donor interactions and electrostatic interactions with the protonated amino side chains of the anthrapyrazoles led to high cell growth inhibitory activity.

Anthracyclines↗