Biomedical subjects

Li Hou

Publications and source records attributed to Li Hou.

At least 19 recordsLinked to original sources

PubMed2006

Identification of differentially expressed genes in mouse hepatocarcinoma ascites cell line with low potential of lymphogenous metastasis.

AIM: To identify genes differentially expressed in mouse hepatocarcinoma ascites cell line with low potential of lymphogenous metastasis. METHODS: A subtracted cDNA library of mouse hepatocarcinoma cell line with low potential of lympho-genous metastasis Hca-P and its synogenetic cell line Hca-F with high metastatic potential was constructed by suppression subtracted hybridization (SSH) method. The screened clones of the subtracted library were sequenced and GenBank homology search was performed. RESULTS: Fifteen differentially expressed cDNA fragments of Hca-P were obtained which revealed 8 known genes, 4 expressed sequence tags (ESTs) and 3 cDNAs showed no homology. CONCLUSION: Tumor metastasis is an incident involving multiple genes. SSH is a useful technique to detect differentially expressed genes and an effective method to clone novel genes.

Animals↗

PubMed2005

Prediction of new superhard boron-rich compounds.

Boron solids exhibit a fascinating geometric and electronic structure. The properties of alpha-rhombohedral boron can be significantly changed by the addition of other atomic constituents. It is found that Pauling's bond valence principle plays an important role in designing boron-rich semiconductors. We have designed the novel boron-rich phases B12N2X (X = Zn, Cd, Be) with the boron carbide type structure by combining Pauling's bond valence principle with first-principles techniques. Their energy gaps, bulk moduli, microhardnesses, and total energies have been calculated. The results show that they are new superhard materials and potential semiconductors. It has been elucidated why B12N2 is metallic but B12N2Be is a semiconductor. This should open up new potential areas for predicting novel boron-rich compounds for industrial applications.

Journal Article↗

PubMed2005

Screening differentially expressed genes in mouse hepatocarcinoma ascites cell line with high potential of lymphatic metastasis.

AIM: To screen genes differentially expressed in mouse hepatocarcinoma ascites cell line with high potential of lymphatic metastasis. METHODS: A subtracted cDNA library of mouse hepatocarcinoma cell line with high potential of lymphatic metastatic Hca-F and its synogenetic cell line Hca-P with a low metastatic potential was constructed by suppression subtracted hybridization(SSH) method. The screened clones of the subtracted library were sequenced and GeneBank homology search was performed. RESULTS: Fourteen differentially expressed cDNA fragments of Hca-F were obtained with two novel genes. CONCLUSION: SSH is a useful technique to detect differentially expressioned genes and an effective method to clone novel genes.

Animals↗

PubMed2005

Identify lymphatic metastasis-associated genes in mouse hepatocarcinoma cell lines using gene chip.

AIM: In order to obtain lymphogenous metastasis-associated genes, we compared the transcriptional profiles of mouse hepatocarcinoma cell lines Hca-F with highly lymphatic metastasis potential and Hca-P with low lymphatic metastasis potential. METHODS: Total RNA was isolated from Hca-F and Hca-P cells and synthesized into double-stranded cDNA. In vitro transcription double-stranded cDNA was labeled with biotin (i.e. biotin-labeled cRNA, used as the probe). The cRNA probes hybridized with Affymetrix GeneChip(r) MOE430A (containing 22 690 transcripts, including 14 500 known mouse genes and 4 371 ESTs) respectively and the signals were scanned by the GeneArray Scanner. The results were then analyzed by bioinformatics. RESULTS: Out of the 14 500 known genes investigated, 110 (0.8%) were up regulated at least 2(3) fold. Among the total 4 371 ESTs, 17 ESTs (0.4%) (data were not presented) were up regulated at least 2(3) fold. According to the Gene Ontology and TreeView analysis, the 110 genes were further classified into two groups: differential biological process profile and molecular function profile. CONCLUSION: Using high-throughput gene chip method, a large number of genes and their cellular functions about angiogenesis, cell adhesion, signal transduction, cell motility, transport, microtubule-based process, cytoskeleton organization and biogenesis, cell cycle, transcription, chaperone activity, motor activity, protein kinase activity, receptor binding and protein binding might be involved in the process of lymphatic metastasis and deserve to be used as potential candidates for further investigation. Cyclin D1, Fosl1, Hsp47, EGFR and AR, and Cav-1 are selected as the possible candidate genes of the metastatic phenotype, which need to be validated in later experiments. ESTs (data were not presented) might indicate novel genes associated with lymphatic metastasis. Validating the function of these genes is helpful to identify the key or candidate gene/pathway responsible for lymphatic metastasis, which might be used as the diagnostic markers and the therapeutic targets for lymphatic metastasis.

Animals↗

PubMed2005

Microsomal triglyceride transfer protein promotes the secretion of Xenopus laevis vitellogenin A1.

Vitellogenins (Vtg) are ancient lipid transport and storage proteins and members of the large lipid transfer protein (LLTP) gene family, which includes insect apolipophorin II/I, apolipoprotein B (apoB), and the microsomal triglyceride transfer protein (MTP). Lipidation of Vtg occurs at its site of synthesis in vertebrate liver, insect fat body, and nematode intestine; however, the mechanism of Vtg lipid acquisition is unknown. To explore whether Vtg biogenesis requires the apoB cofactor and LLTP family member, MTP, Vtg was expressed in COS cells with and without coexpression of the 97-kDa subunit of human MTP. Expression of Vtg alone gave rise to a approximately 220-kDa apoprotein, which was predominantly confined to an intracellular location. Coexpression of Vtg with human MTP enhanced Vtg secretion by 5-fold, without dramatically affecting its intracellular stability. A comparison of wild type and a triglyceride transfer-defective form of MTP revealed that both were capable of promoting Vtg secretion, whereas only wild type MTP could promote the secretion of apoB41 (amino-terminal 41% of apoB). These studies demonstrate that the biogenesis of Vtg is MTP-dependent and that MTP is the likely ancestral member of the LLTP gene family.

Alkaline Phosphatase↗

PubMed2005

[Screening of differentially expressed genes in mouse hepatocarcinoma ascites cell line with high potential of lymphatic metastasis].

OBJECTIVE: To screen genes differentially expressed in mouse hepatocarcinoma ascites cell line with high potential of lymphatic metastasis. METHODS: A subtracted cDNA library of mouse hepatocarcinoma cell line with high potential of lymphatic metastasis Hca-F and its synogenetic cell line Hca-P with low metastatic potential was constructed by suppression subtractive hybridization (SSH) method. The screened clones of the subtracted library were sequenced and GenBank homology search was performed. RESULTS: Ten differentially expressed cDNA fragments of Hca-F with high potential of lymphatic spreading were obtained, two of which were newly identified ones. CONCLUSION: SSH is a useful technique to detect genes of differential expression and an effective method to clone novel genes.

Animals↗

PubMed2005

[Screening for lymphatic metastasis-associated genes in mouse hepatocarcinoma cell lines Hca-F and Hca-P using gene chip].

BACKGROUND & OBJECTIVE: Metastasis is a complex process involving multiple genetic changes. The high mortality and poor prognosis caused by metastasis in malignant tumor patients and the uncertain mechanisms are always the prominent problems in the field of oncology. In order to screen for lymphatic metastasis-associated genes, the gene expression profiles of mouse hepatocarcinoma cell lines Hca-F (highly metastatic) and Hca-P (low metastatic) were compared by gene chip. METHODS: Total RNA was isolated from Hca-F and Hca-P cells, and synthesized into double-stranded cDNA, then synthesized into biotin-labeled cRNA probes by in vitro transcription. The cRNA probes were separately hybridized with Affymetrix GeneChip MOE430A (containing 22,690 transcripts, including 14,500 known mouse genes and 4,371 ESTs), and the signals were scanned by the GeneArray Scanner. The results were analyzed by bioinformatics. RESULTS: Compared with the gene expression profile of Hca-P cells, 901 (6.2%) genes and 129 (3%) ESTs were up-regulated by at least 2 folds in Hca-F cells; 33 genes, including endoglin (EDG; CD105), Mcam (Muc18; Mel-CAM; CD146), Cdc42ep5 (CEP5; Borg3), Ptprr (protein tyrosine phosphatase, receptor type, R), F2r [coagulation factor II (thrombin) receptor; Par1; ThrR], D7Ertd458e (necl-5), NR1D1, Serpin h1 (HSP47), AXL, Mak, and Areg (AR), were up-regulated 13.93-29.86 folds. According to Gene Ontology and Treeview analysis, these 33 genes were involved in angiogenesis, cell adhesion, signal transduction, cell motility, transcription, chaperone activity, protein kinase activity, receptor binding, and so on. CONCLUSION: Many lymphatic metastasis-associated genes were screened by high-throughput gene chip method; validating their cellular functions will help to identify the key or candidate gene/pathway responsible for lymphatic metastasis, which might be used as diagnostic markers and therapeutic targets for lymphatic metastasis.

Animals↗

PubMed2005

[Relationship of mitochondrial DNA mutation with myelodysplastic syndromes - review].

Myelodysplastic syndromes are refered to as a group of diseases characterized by abnormal clonal proliferation of hematopoietic stem cells with pancytopenia and dysplasia. Recently, it has been documented that ringed sideroblasts are not only confined to the refractory anemia with ring sideroblast (RARS) subtype of MDS, but also contribute to numerous underlying MDS pathophysiological processes as a significant feature of dysplasia. This clonal heterogeneity suggested a pathogenetic role of mitochondrial DNA mutation. Many studies have shown that mitochondrial respiratory chain defects resulting from mutation of mitochondrial DNA may lead to multiple pathophysiologic changes, and may impact on the pathogeneses of MDS.

Apoptosis↗

PubMed2005

[Extracting techniques for optimizing zi shen granule by orthogonal text].

OBJECTIVE: To optimize the extracting techniques for Zi Shen Granule. METHODS: By taking the rate of extractum and the total of anthraquinone as the indexes components, the extraction techniques were optimized for Zi Shen Granule through L9 (3) 4 orthogonal text. RESULTS: The best condition is twice extraction by 2h or 1.5 h, to add octuple water. Then the water solution was concentrated to relative concentration 1.10, and adds ethanol to 70% alcohol Concentration,then stewing 24h. CONCLUSION: The optemized extraction technique is rational and jarless and ideal for mass production.

Analysis of Variance↗

PubMed2005

[Construction of co-expression vector pSLC-IRES-IL-2 and its expression in COS-7 cells].

AIM: To construct an eukaryotic co-expression plasmid pSLC-IRES-IL-2, and to express it in COS-7 cells. METHODS: Human IL-2 and SLC genes were cloned by RT-PCR and PCR, respectively, and then the eukaryotic expression plasmid pSLC-IRES-IL-2 was constructed.The constructed plasmid was transfected into COS-7 cells by electroporation method. The expression of SLC and IL-2 was detected by Western blot. RESULTS: SLC and IL-2 in the culture supernatant and lysate of transfected COS-7 cells were detected by Western blot. The relative molecular masses of the expressed products were consistent with the theoretical values. CONCLUSION: The SLC and IL-2 co-expression plasmid is successfully constructed and expressed in COS-7 cells, which offers a pathway for research on gene therapy of tumors.

Animals↗

PubMed2004

Construction and selection of subtracted cDNA library of mouse hepatocarcinoma cell lines with different lymphatic metastasis potential.

AIM: In order to elucidate the molecular mechanism of lymphatic metastasis of hepatocarcinoma, we detected the difference of gene expression between mouse hepatocarcinoma cell lines Hca-F and Hca-P with different lymphatic metastasis potential. METHODS: cDNA of Hca-F cells was used as a tester and cDNA of Hca-P cells was used as a driver. cDNAs highly expressed in Hca-F cells were isolated by the suppression subtractive hybridization (SSH) method. The isolated cDNA was cloned into T/A cloning vector. The ligation products were transformed into DH5alpha competent cells. Individual clones were randomly selected and used for PCR amplification. Vector DNA from positive clones was isolated for sequencing. RESULTS: There were 800 positive clones in amplified subtracted cDNA library. Random analysis of 160 clones with PCR showed that 95% of the clones contained 100-700 bp inserts. Analysis of 20 sequenced cDNA clones randomly picked from the SSH library revealed 4 known genes (mouse heat shock protein 84 ku, DNA helicase, ribosomal protein S13, ethanol induced 6 gene) and 3 expressed sequence tags (ESTs). Four cDNAs showed no homology and presumably represent novel genes. CONCLUSION: A subtracted cDNA library of differentially expressed genes in mouse heptocarcinoma cell lines with different lymphatic metastasis potential was successfully constructed with SSH and T/A cloning techniques. The library is efficient and lays a solid foundation for searching new lymphatic metastasis related genes. The expression of mouse heat shock protein gene, DNA helicase and other 4 novel gene may be different between mouse heptocarcinoma cell lines with different lymphatic metastasis potential.

Animals↗

PubMed2004

Determination of pesticides in soil by liquid-phase microextraction and gas chromatography-mass spectrometry.

Trace amounts of pesticides in soil were determined by liquid-phase microextraction (LPME) coupled to gas chromatography-mass spectrometry (GC-MS). The technique involved the use of a small amount (3 microl) of organic solvent impregnated in a hollow fiber membrane, which was attached to the needle of a conventional GC syringe. The organic solvent was repeatedly discharged into and withdrawn from the porous polypropylene hollow fiber by a syringe pump, with the pesticides being extracted from a 4 ml aqueous soil sample into the organic solvent within the hollow fiber. Aspects of the developed procedure such as organic solvent selection, extraction time, movement pattern of plunger, concentrations of humic acid and salt, and the proportion of organic solvent in the soil sample, were optimized. Limits of detection (LOD) were between 0.05 and 0.1 microg/g with GC-MS analysis under selected-ion monitoring (SIM). Also, this method provided good precision ranging from 6 to 13%; the relative standard deviations were lower than 10% for most target pesticides (at spiked levels of 0.5 microg/g in aqueous soil sample). Finally, the results were compared to those achieved using solid-phase microextraction (SPME). The results demonstrated that LPME was a fast (within 4 min) and accurate method to determine trace amounts of pesticides in soil.

Gas Chromatography-Mass Spectrometry↗

PubMed2003

Identification of the lipoprotein initiating domain of apolipoprotein B.

We have explored the minimum sequence requirement for the initiation of apolipoprotein B (apoB)-mediated triglyceride-rich lipoprotein assembly. A series of apoB COOH-terminal truncation mutants, spanning a range from apoB34 (amino acid residues 1-1544 of apoB100) to apoB19 (residues 1-862) were transfected into COS cells with and without coexpression of the microsomal triglyceride transfer protein (MTP). ApoB34, -25, -23, -21, -20.5, and -20.1 underwent efficient conversion to buoyant lipoproteins when coexpressed with MTP. ApoB19.5 (amino acids 1-884) also directed MTP-dependent particle assembly, although at reduced efficiency. When apoB19.5 was truncated by another 22 amino acids to form apoB19, MTP-dependent lipoprotein assembly was abolished. Analysis of the lipid stoichiometry of secreted lipoproteins revealed that all apoB truncation mutants formed spherical particles containing a hydrophobic core. Even highly truncated assembly-competent forms of apoB, such as apoB19.5 and 20.1, formed lipoproteins with surface:core lipid ratios of <1. We conclude that the translation of the first approximately 884 amino acids of apoB completes a domain capable of initiating nascent lipoprotein assembly. The composition of lipids recruited into lipoproteins by this initiating domain is consistent with formation of small emulsion particles, perhaps by simultaneous desorption of both polar and neutral lipids from a saturated bilayer.

Animals↗

PubMed2003

Dynamic three-phase microextraction as a sample preparation technique prior to capillary electrophoresis.

Dynamic three-phase (liquid-liquid-liquid) microextraction was developed for capillary electrophoresis. Four aromatic amines as model compounds were extracted from 4-mL aqueous samples adjusted to basic condition (donor solution) through a small volume of organic solvent impregnated in a hollow fiber, which was held by the needle of a conventional syringe, and retracted into a 5-microL acidic acceptor solution inside the syringe. A renewable organic film and aqueous sample plug were formed inside the hollow fiber with the repeated movement of the syringe plunger enabled by a programmable syringe pump. This is believed to be the first reported instance of a semiautomated dynamic liquid-liquid-liquid microextraction (LLLME) procedure. Following this microextraction, the 5-microL acceptor solution was analyzed by capillary zone electrophoresis (CE). This new technique provided approximately 140-fold enrichment in 20 min. Utilizing 4-chloroaniline as internal standard, dynamic LLLME could provide good reproducibility (<4.0%). In addition, this method allowed the direct transfer of extracted analytes to a CE system for analysis.

Journal Article↗

PubMed2003

A Drosophila microsomal triglyceride transfer protein homolog promotes the assembly and secretion of human apolipoprotein B. Implications for human and insect transport and metabolism.

The assembly and secretion of triglyceride-rich lipoproteins in vertebrates requires apolipoprotein B (apoB) and the endoplasmic reticulum-localized cofactor, microsomal triglyceride transfer protein (MTP). Invertebrates, particularly insects, transport the majority of their neutral and polar lipids in lipophorins; however, the assembly of lipophorin precursor particles was presumed to be MTP-independent. A Drosophila melanogaster expressed gene sequence (CG9342), displaying 23% identity with human MTP, was recently identified. When coexpressed in COS cells, CG9342 promoted the assembly and secretion of apoB34 and apoB41 (N-terminal 34 and 41% of human apoB). The apoB34-containing particles assembled by human MTP and CG9342 displayed similar peak densities of approximately 1.169 g/ml and similar lipid compositions. However, CG9342 displayed differential sensitivities to two inhibitors of human MTP and low vesicle-based lipid transfer activity, in vitro. In addition, important predicted structural distinctions exist between the human and Drosophila proteins suggesting overlapping but not identical functional roles. We conclude that CG9342 and human MTP are orthologs that share only a subset of functions, consistent with known differences in intracellular and extracellular aspects of vertebrate and invertebrate lipid transport and metabolism.

Amino Acid Sequence↗

PubMed2003

Automated hollow fiber-protected dynamic liquid-phase microextraction of pesticides for gas chromatography-mass spectrometric analysis.

Dynamic liquid-phase microextraction (LPME) controlled by a programmable syringe pump was evaluated for extracting pesticides in water prior to GC-MS analysis. A conventional microsyringe with a 1.3-cm length of hollow fiber attached to its needle was connected to a syringe pump to perform the extraction. The microsyringe was used as both the microextraction device as well as the sample introduction device for GC-MS analysis. The attached hollow fiber served as the "holder" and protector" of 3 microl of organic solvent. The solvent was repeatedly withdrawn into and discharged from the hollow fiber by the syringe pump. Pesticides were extracted from 4-ml water samples into the organic solvent impregnated in the hollow fiber. The effects of organic solvents, plunger movement pattern, agitation and extraction time were investigated. Good repeatabilities of extraction performance were obtained, with the RSD values ranging from 3.0% (alachlor) to 9.8% (4-chlorophenol) for the 14 pesticides; most RSD values were under 5.0%. The method provided a 490-fold preconcentration of the target pesticides. The limits of detection were in the range of 0.01-5.1 microg/l (S/N = 3) in the GC-MS selected ion monitoring mode. In addition, sample clean-up was achieved during LPME because of the selectivity of the hollow fiber, which prevented undesirable large molecules from being extracted. A slurry sample (mixture of 40 mg soil/ml of water) containing seven pesticides was extracted using this method which also gave good linearity and precision (most RSDs <7.0%, n = 3).

Gas Chromatography-Mass Spectrometry↗

PubMed2003

[Study on efficacy of "bushen huoxue liquid" in male rats with osteoporosis induced by dexamethasone and its mechanism].

OBJECTIVE: To study the efficacy of "Bushen Huoxue Liquid" (BSHXL) in male rats with osteoporosis induced by dexamethasone (DM) and its mechanism. METHODS: Forty-six male Sprague-Dawley rats at 18 months of age were chosen. They were divided into four groups, BSHXL and DM were administered appropriately for 12 weeks. General bone mineral density (GBMD), femur bending strength (FBS), serum-BGP, serum-PTH and serum-E2 were measured. RESULTS: GBMD, FBS in BSHXL prevention group were significantly higher than those in DM group (P < 0.01), and the same with those in normal control group (P > 0.05). GBMD, FBS in BSHXL treatment group were higher than those in DM group (P < 0.05), and lower than those in normal control group. Compared with DM group, level of serum-T in BSHXL prevention group and BSHXL treatment group increased (P < 0.05) and level of serum-PTH in those two groups decreased (P < 0.05). But in comparison with DM group, level of serum-E2 and serum-BGP in the above-mentioned two groups had no significant difference (P > 0.05). CONCLUSION: BSHXL could prevent and treat osteoporosis in male rats induced by DM.

Animals↗

PubMed2002

Combination of liquid-phase microextraction and on-column stacking for trace analysis of amino alcohols by capillary electrophoresis.

We described a new method for the enrichment of basic drugs present in water samples via liquid-phase microextraction (LPME) combined with on-column stacking in capillary electrophoresis. Two steps were employed to enhance the detection sensitivity of four amino alcohols. The analytes were first extracted from aqueous sample (donor solution) that were adjusted to basic through a thin layer of 1-octanol entrapped within the pores of a polypropylene hollow fiber, and then into a 5-microl acidic acceptor solution inside the hollow fiber. The extract was then further enriched through on-column stacking in capillary electrophoresis. With this two-step enrichment procedure, the method provided 72-110-fold preconcentration of the target amino alcohols. The limits of detection were 0.08-0.5 microg/ml. Relative standard deviation (n=6) ranged between 4.3 and 6.9% for the studied drugs utilizing 2-amino-1-phenylethanol as internal standard. The extraction of amino alcohols in spiked urine samples was evaluated using the developed procedure.

Amino Alcohols↗