Biomedical subjects

Yan Li

Publications and source records attributed to Yan Li.

At least 451 records · Page 25Linked to original sources

PubMed2004

Methylenetetrahydrofolate reductase C677T polymorphism and predisposition towards esophageal squamous cell carcinoma in a German Caucasian and a northern Chinese population.

PURPOSE: Folate deficiency is considered to increase the risk of developing esophageal cancer. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme involved in folate metabolism. A single C --> T substitution at nucleotide 677 of the MTHFR cDNA influences enzyme activity. The purpose of this study is to compare the association of the MTHFR C677T polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC). METHODS: Using real-time PCR and melting curve analysis, the MTHFR C677T genotypes were determined in 430 patients with ESCC (241 German Caucasians and 189 northern Chinese) and 397 unrelated healthy controls (256 German Caucasians and 141 northern Chinese). RESULTS: A significant difference in MTHFR C677T genotype distribution was observed between German Caucasian controls (C/C, 41.8%, C/T, 44.9%, T/T, 13.3%) and northern Chinese controls (C/C, 17.7%, C/T, 38.3%, T/T, 44.0%) (chi(2)=52.19, P<0.001). The distribution of the MTHFR C677T genotypes among German ESCC patients (C/C, 39.0%, C/T, 48.1%, T/T, 12.9%) was not significantly different from that among healthy controls (chi(2)=0.531, P=0.767). In contrast, the frequency of the C/C genotype among Chinese ESCC patients (8.5%) was significantly lower than among Chinese healthy controls (17.7%) (chi(2)=6.37, P=0.012). The C/C genotype was correlated with a significantly reduced risk for the development of ESCC as compared to the combination of C/T and T/T genotypes (adjusted OR=0.38, 95% CI=0.16-0.88). CONCLUSIONS: Our results suggest that, in contrast to German Caucasians, the MTHFR 677CC homozygous wild-type plays a protective role in the development of ESCC in the northern Chinese population.

Asian People↗

PubMed2004

Association of the thymidylate synthase polymorphisms with esophageal squamous cell carcinoma and gastric cardiac adenocarcinoma.

Polymorphisms in the untranslated regions (UTRs) of the thymidylate synthase (TS) gene, which may modulate TS transcription and expression, have been associated with susceptibility and prognosis of several tumors. However, their effects on the development and clinical staging of esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) have not been assessed so far. In this study, the 28-bp tandem repeat and the G/C single nucleotide polymorphism in the TS 5'UTR, the 6-bp deletion (6 bp-) polymorphism in the TS 3'UTR, were genotyped in 465 cancer patients (232 ESCC, 233 GCA) and 348 control subjects in North China. The genotype and allelotype distribution of the TS variants in ESCC, GCA patients and controls did not show significant difference. However, the frequency of the 6 bp-/2R haplotype in ESCC and GCA patients was marginally or significantly lower than that in controls (P = 0.05 and 0.006, respectively). Thus, the 6 bp-/2R significantly reduced the risk to ESCC and GCA, compared with the 6 bp-/3G haplotype [odds ratio (OR) = 0.61 and 0.48, 95% confidence interval (CI) = 0.37-1.00 and 0.28-0.81, respectively]. In addition, the 6 bp+/3G haplotype in ESCC patients was also significantly less common than in controls (P = 0.002). Compared with the 6 bp-/3G haplotype, the 6 bp+/3G significantly reduced the risk to ESCC (OR = 0.30, 95% CI = 0.14-0.67). Moreover, the TS 2R/3G genotype frequency in ESCC patients with and without lymphatic metastasis was significantly different (27.1 versus 4.9%, P < 0.001). Therefore, the 2R/3G genotype had an approximately 11-fold increase in the risk of lymphatic metastasis of ESCC, compared with the 3G/3G genotype (95% CI = 2.67-49.74). The results suggested that the TS polymorphisms might be associated with the susceptibility to ESCC and GCA, and the 2R/3G genotype might be a candidate marker to predict the potential of lymphatic metastasis in ESCC.

Adenocarcinoma↗

PubMed2004

Spectral, structural, and electrochemical properties of ruthenium porphyrin diaryl and aryl(alkoxycarbonyl) carbene complexes: influence of carbene substituents, porphyrin substituents, and trans-axial ligands.

A wide variety of ruthenium porphyrin carbene complexes, including [Ru(tpfpp)(CR(1)R(2))] (CR(1)R(2) = C(p-C(6)H(4)Cl)(2) 1 b, C(p-C(6)H(4)Me)(2) 1 c, C(p-C(6)H(4)OMe)(2) 1 d, C(CO(2)Me)(2) 1 e, C(p-C(6)H(4)NO(2))CO(2)Me 1 f, C(p-C(6)H(4)OMe)CO(2)Me 1 g, C(CH==CHPh)CO(2)CH(2)(CH==CH)(2)CH(3) 1 h), [Ru(por)(CPh(2))] (por=tdcpp 2 a, 4-Br-tpp 2 b, 4-Cl-tpp 2 c, 4-F-tpp 2 d, tpp 2 e, ttp 2 f, 4-MeO-tpp 2 g, tmp 2 h, 3,4,5-MeO-tpp 2 i), [Ru(por)[C(Ph)CO(2)Et]] (por=tdcpp 2 j, tmp 2 k), [Ru(tpfpp)(CPh(2))(L)] (L = MeOH 3 a, EtSH 3 b, Et(2)S 3 c, MeIm 3 d, OPPh(3) 3 e, py 3 f), and [Ru(tpfpp)[C(Ph)CO(2)R](MeOH)] (R = CH(2)CH==CH(2) 4 a, Me 4 b, Et 4 c), were prepared from the reactions of [Ru(por)(CO)] with diazo compounds N(2)CR(1)R(2) in dichloromethane and, for 3 and 4, by further treatment with reagents L. A similar reaction of [Os(tpfpp)(CO)] with N(2)CPh(2) in dichloromethane followed by treatment with MeIm gave [Os(tpfpp)(CPh(2))(MeIm)] (3 d-Os). All these complexes were characterized by (1)H NMR, (13)C NMR, and UV/Vis spectroscopy, mass spectrometry, and elemental analyses. X-ray crystal structure determinations of 1 d, 2 a,i, 3 a, b, d, e, 4 a-c, and 3 d-Os revealed Ru==C distances of 1.806(3)-1.876(3) A and an Os==C distance of 1.902(3) A. The structure of 1 d in the solid state features a unique "bridging" carbene ligand, which results in the formation of a one-dimensional coordination polymer. Cyclic voltammograms of 1 a-c, g, 2 a-d, g-k, 3 b-d, 4 a, b, and 3 d-Os show a reversible oxidation couple with E(1/2) values in the range of 0.06-0.65 V (vs Cp(2)Fe(+/0)) that is attributable to a metal-centered oxidation. The influence of carbene substituents, porphyrin substituents, and trans-ligands on the Ru==C bond was examined through comparison of the chemical shifts of the pyrrolic protons in the porphyrin macrocycles ((1)H NMR) and the M==C carbon atoms ((13)C NMR), the potentials of the metal-centered oxidation couples, and the Ru==C distances among the various ruthenium porphyrin carbene complexes. A direct comparison among iron, ruthenium, and osmium porphyrin carbene complexes is made.

Journal Article↗

PubMed2004

Hemoglobin levels in Qinghai-Tibet: different effects of gender for Tibetans vs. Han.

The Tibetan population, long a resident on the Qinghai-Tibetan Plateau, has lower hemoglobin concentrations than Han Chinese migrants, but it is incompletely known how gender affects the hemoglobin concentrations in the two populations at various altitudes. Measurements of hemoglobin concentration were obtained in 5,887 healthy male and female Tibetan and Han residents aged 5-60 yr, at altitudes of 2,664, 3,813, 4,525, and 5,200 m. Multiple regression equations showed the beta-coefficients for altitude and for age were higher (P < 0.05) in Han men than in Tibetan men and in Han women than in Tibetan women. Analysis indicated a significant three-way interaction between altitude, gender, and ethnicity (chi2 = 3.72, P = 0.05). With increasing altitude, men progressively had more hemoglobin than women in the Han, but not the Tibetan, population. Above 2,664 m, this gender-related difference in hemoglobin concentration increased from childhood to young adulthood more in Han than in Tibetans. We suggest that the Han-Tibetan ethnic difference in the effect of altitude on hemoglobin concentration depends to a large extent on gender.

Adolescent↗

PubMed2004

Caldesmon mutant defective in Ca(2+)-calmodulin binding interferes with assembly of stress fibers and affects cell morphology, growth and motility.

Despite intensive in vitro studies, little is known about the regulation of caldesmon (CaD) by Ca(2+)-calmodulin (Ca(2+)-CaM) in vivo. To investigate this regulation, a mutant was generated of the C-terminal fragment of human fibroblast CaD, termed CaD39-AB, in which two crucial tryptophan residues involved in Ca(2+)-CaM binding were each replaced with alanine. The mutation abolished most CaD39-AB binding to Ca(2+)-CaM in vitro but had little effect on in vitro binding to actin filaments and the ability to inhibit actin/tropomyosin-activated heavy meromyosin ATPase. To study the functional consequences of these mutations in vivo, we transfected an expression plasmid carrying CaD39-AB cDNA into Chinese hamster ovary (CHO) cells and isolated several clones expressing various amounts of CaD39-AB. Immunofluorescence microscopy revealed that mutant CaD39-AB was distributed diffusely throughout the cytoplasm but also concentrated at membrane ruffle regions. Stable expression of CaD39-AB in CHO cells disrupted assembly of stress fibers and focal adhesions, altered cell morphology, and slowed cell cycle progression. Moreover, CaD39-AB-expressing cells exhibited motility defects in a wound-healing assay, in both velocity and the persistence of translocation, suggesting a role for CaD regulation by Ca(2+)-CaM in cell migration. Together, these results demonstrate that CaD plays a crucial role in mediating the effects of Ca(2+)-CaM on the dynamics of the actin cytoskeleton during cell migration.

Actins↗

PubMed2004

[Prokaryotic expression, purification and preparation of polyclonal antibody and immunohistochemistry analysis of RS21-C6 molecule].

OBJECTIVE: To express a thymocyte development related molecule RS21-C6 protein prepare its polyclonal antibodies and study its distribution in thymus by immunohistochemistry analysis. METHODS: RS21-C6 recombinant protein was expressed in E.coli system and then purified by Ni-NTA chromatographic method. Polyclonal antibodies were prepared by immunized rabbits with the purified recombinant protein. Immunohistochemistry analysis was performed to show the distribution of RS21-C6 in mouse thymus tissue. RESULTS: RS21-C6 recombinant protein was successfully expressed and purified. Then the high titer polyclonal antibody was prepared and its specificity was confirmed. The immunohistochemistry analysis demonstrated that RS21-C6 had an intense expression in the medullary region of thymus while scattered in the cortical region and the cortical medullary junction region of thymus. It also showed that RS21-C6 was co-expressed in thymocyte and thymic stromal cells. CONCLUSION: RS21-C6 molecule is broadly and highly expressed in thymus which suggests that this molecule may perform various functions in thymocytes at different developmental stages.

Animals↗

PubMed2004

A mouse mammary tumor virus-like long terminal repeat superantigen in human breast cancer.

We previously reported a 660-bp mouse mammary tumor virus (MMTV)-like env gene sequence in approximately 38% of human breast cancer DNA, but not in normal breasts or other tumors. This MMTV-like env gene sequence was expressed in 66% of the env gene-positive human breast cancers. An entire proviral structure was identified in human breast cancer DNA with high homology to MMTV and low homology to known human endogenous retrovirus. MMTV-like long terminal repeat (LTR) sequences were also detected in 41.5% of human breast cancers. They contain hormone-responsive elements, TEF-1 family elements, and the open reading frame for the superantigen (SAg). We have now amplified and sequenced MMTV-like sag sequences from 10 human breast cancers, and we found that they are highly homologous to those of MMTV. However, deletions and insertions at the COOH-terminal of sag were observed. The immune function of the human MMTV-like LTR SAg was also investigated. The sag gene was cloned and expressed in a human B-cell line (Ramos). T-cell proliferation and cytokine releasing assays were performed after cocultivation of T cells with irradiated Ramos SAg-expressing cells. The results indicate that expression of the human SAg stimulates T-cell activation in vitro, as the mouse SAg does. Because the T-cell responses in vitro are considered similar to those in vivo, these results suggest that the human LTR SAg might also play a role in human breast carcinogenesis.

Amino Acid Sequence↗

PubMed2004

Polymorphisms of interleukin-1B and interleukin-1 receptor antagonist genes in patients with chronic hepatitis B.

AIM: To investigate the relationships between polymorphisms of interleukin-1B (IL-1B) promoter region -511C/T and interleukin-1 receptor antagonist gene (IL-1RN) and susceptibility to chronic hepatitis B in Chinese population. METHODS: Genomic DNA was extracted from the peripheral blood of 190 patients with chronic hepatitis B and 249 normal controls and then subjected to polymerase chain reaction (PCR) amplification. The PCR products were digested by restriction endonuclease AvaI. The products of digestion were subjected to 20 g/L gel electrophoresis and ethidium bromide staining. RESULTS: The frequencies of IL-1B (-511) genotypes CC, CT and TT in patients with chronic hepatitis B were 23.7%, 49.5% and 26.8%, while 26.1%, 47.4% and 26.5% respectively in controls. The results showed that there was no significant difference in the frequencies of alleles or genotypes in IL-1B between patients with chronic hepatitis B and controls. The distributions of IL-1B (-511) genotype CC were significantly different between the two subgroups (HBV-DNA </=1x10(3) copies/mL as subgroup I, HBV-DNA >1x10(3) copies/mL as subgroup II) of chronic hepatitis B (P=0.029). Only four of the five kinds of polymorphism (1/1, 1/2, 2/2 and 1/4) were found in this study. The frequencies of IL-1RN genotypes 1/1, 1/2, 2/2 and 1/4 were 88.9%, 9.0%, 0.5% and 1.6% in patients with chronic hepatitis B respectively, while were 81.1%, 16.9%, 0.4% and 1.6% respectively in controls. The frequencies of genotype1/2 and IL-1RN allele 2 in patients with chronic hepatitis B were lower than those in controls (P=0.016 and P=0.029, respectively). CONCLUSION: There is an association between polymorphisms of the promoter region -511C/T of IL-1B and IL-1RN intron 2 and chronic hepatitis B virus infection. Subjects with IL-1RN allele 2 may be resistant to HBV infection, and IL-1B(-511)genotype CC is closely related with HBV-DNA replication, which gives some new clues to the study of pathogenesis of chronic hepatitis B.

Adolescent↗

PubMed2004

Subtractive proteomic mapping of the endothelial surface in lung and solid tumours for tissue-specific therapy.

The molecular complexity of tissues and the inaccessibility of most cells within a tissue limit the discovery of key targets for tissue-specific delivery of therapeutic and imaging agents in vivo. Here, we describe a hypothesis-driven, systems biology approach to identifying a small subset of proteins induced at the tissue-blood interface that are inherently accessible to antibodies injected intravenously. We use subcellular fractionation, subtractive proteomics and bioinformatics to identify endothelial cell surface proteins exhibiting restricted tissue distribution and apparent tissue modulation. Expression profiling and gamma-scintigraphic imaging with antibodies establishes two of these proteins, aminopeptidase-P and annexin A1, as selective in vivo targets for antibodies in lungs and solid tumours, respectively. Radio-immunotherapy to annexin A1 destroys tumours and increases animal survival. This analytical strategy can map tissue- and disease-specific expression of endothelial cell surface proteins to uncover novel accessible targets useful for imaging and therapy.

Aminopeptidases↗

PubMed2004

Rheology of hydrophobically modified polyacrylamide-co-poly(acrylic acid) on addition of surfactant and variation of solution pH.

Constant shear and shear dependent viscosity measurements are reported in aqueous systems of co- and terpolymers of acrylamide (AM), N-n-alkylacrylamide (C10, C12, and C14 alkyl groups), and acrylic acid (AA) with added anionic surfactant sodium dodecyl sulfate (SDS). The results are presented as three-dimensional plots of viscosity vs surfactant concentration and pH at constant shear rate or viscosity vs shear rate and surfactant concentration at constant pH. For terpolymers incorporating AA, a strong viscosity maximum is observed at intermediate pH values (pH 4-6) where the AA groups are partially ionized and at SDS concentrations close to the critical micelle concentration. At high pH, all AA incorporating terpolymer solutions with SDS are strongly shear thinning, but at pH 3-4 the systems of terpolymers with SDS are strongly shear thickening at low shear, followed by a shear-thinning region at high shear. These results are explained in terms of surfactant-mediated network formation with polymer coil expansion and hydrogen bonding between partially ionized AA groups as additional factors.

Journal Article↗

PubMed2004

Equine estrogen metabolite 4-hydroxyequilenin induces anchorage-independent growth of human mammary epithelial MCF-10A cells: differential gene expression.

Long-term exposure to synthetic and endogenous estrogens has been associated with the development of cancer in several tissues. One potential mechanism of estrogen carcinogenesis involves catechol formation and these catechols are further oxidized to electrophilic/redox active o-quinones, which have the potential to both initiate and promote the carcinogenic process. Previously we showed that 4-hydroxyequilenin (4-OHEN) autoxidized to an o-quinone and caused a variety of damage to DNA. Since these deleterious effects could contribute to gene mutations, we investigated the Chinese hamster V79 cells to ascertain the relative ability of estradiol, 4-hydroxyestradiol, 17beta-hydroxyequilenin, 4,17beta-hydroxyequilenin, estrone, 4-hydroxyestrone, equilenin, and 4-hydroxyequilenin to induce the mutation of the hypoxanthine-guanine phosphoribosyltransferase (hprt) gene. All the 4-hydroxylated catechols induced significantly more colony formations in V79 cells as compared to the parent phenols at 100nM, suggesting that the catechol estrogen metabolites are more mutagenic towards the hprt gene than estrogens. Since 4-OHEN induced the highest mutation frequency, we examined a biomarker for transformation potential of this compound in MCF-10A cells using an anchorage-independent growth assay. Although 4-OHEN induced anchorage-independent growth of these cells, the isolated clones were not able to grow as tumors in vivo when injected into nude mice. These cells were assayed for genetic changes using cDNA microarrays. Real time RT-PCR confirmation of some of the differentially expressed genes showed down-regulation of metallothionein 2A, p53, BRCA1, and c-myc. Moreover, we showed the involvement of other genes important in cell transformation and oxidative stress, strengthening the hypothesis that this mechanism plays a considerable role in 4-OHEN-induced anchorage-independent growth.

Animals↗

PubMed2004

Control of pore size and permeability of a glucose-responsive gating membrane for insulin delivery.

The pore size and permeability control of a glucose-responsive gating membrane with plasma-grafted poly(acrylic acid) (PAAC) gates and covalently bound glucose oxidase (GOD) enzymes were investigated systematically. The PAAC-grafted porous polyvinylidene fluoride (PVDF) membranes with a wide range of grafting yields were prepared using a plasma-graft pore-filling polymerization method, and the immobilization of GOD was carried out by a carbodiimide method. The linear grafted PAAC chains in the membrane pores acted as the pH-responsive gates or actuators. The immobilized GOD acted as the glucose sensor and catalyzer; it was sensitive to glucose and catalyzed the glucose conversion to gluconic acid. The experimental results showed that the glucose responsivity of the solute diffusional permeability through the proposed membranes was heavily dependent on the PAAC grafting yield, because the pH-responsive change of pore size governed the glucose-responsive diffusional permeability. It is very important to design a proper grafting yield for obtaining an ideal gating response. For the proposed gating membrane with a PAAC grafting yield of 1.55%, the insulin permeation coefficient after the glucose addition (0.2 mol/l) was about 9.37 times that in the absence of glucose, presenting an exciting result on glucose-sensitive self-regulated insulin permeation.

Drug Delivery Systems↗

PubMed2004

On-line coupling of flow injection displacement sorption preconcentration to high-performance liquid chromatography for speciation analysis of mercury in seafood.

A simple and cost-effective method for speciation analysis of trace mercury in seafood was developed by on-line coupling flow injection microcolumn displacement sorption preconcentration to high-performance liquid chromatography (HPLC) with UV detection. The methodology involved the presorption of the Cu-PDC (pyrrolidine dithiocarbamate) chelate onto a microcolumn packed with a cigarette filter sorbent, simultaneous preconcentration of Hg(II), methylmercury (MeHg), ethylmercury (EtHg), and phenylmercury (PhHg) onto the microcolumn through a displacement reaction with the presorbed Cu-PDC, and their subsequent elution from the microcolumn for on-line HPLC separation. Interferences from heavy metal ions with lower stability of their PDC chelates relative to Cu-PDC were minimized without the need of any masking agents. With the consumption of 4.0 ml of sample solution, the enrichment factors were about 80. The detection limits were 10-25 ng g(-1) (as Hg) in fresh tissue. Precision (R.S.D. (%), n = 5) ranged from 2 to 3% at the 500 microg l(-1) (as Hg) level. The developed technique was validated by analyzing a certified reference material (DORM-2, dogfish-muscle), and was shown to be useful for mercury speciation in real seafood samples.

Chromatography, High Pressure Liquid↗

PubMed2004

Transcriptome characterization elucidates signaling networks that control human ES cell growth and differentiation.

Human embryonic stem (hES) cells hold promise for generating an unlimited supply of cells for replacement therapies. To characterize hES cells at the molecular level, we obtained 148,453 expressed sequence tags (ESTs) from undifferentiated hES cells and three differentiated derivative subpopulations. Over 32,000 different transcripts expressed in hES cells were identified, of which more than 16,000 do not match closely any gene in the UniGene public database. Queries to this EST database revealed 532 significantly upregulated and 140 significantly downregulated genes in undifferentiated hES cells. These data highlight changes in the transcriptional network that occur when hES cells differentiate. Among the differentially regulated genes are several components of signaling pathways and transcriptional regulators that likely play key roles in hES cell growth and differentiation. The genomic data presented here may facilitate the derivation of clinically useful cell types from hES cells.

Antigens, CD↗

PubMed2004

Stepwise metastatic human hepatocellular carcinoma cell model system with multiple metastatic potentials established through consecutive in vivo selection and studies on metastatic characteristics.

PURPOSE: To establish a "stepwise metastatic human hepatocellular carcinoma (HCC) cell model system" for in-depth study of the underlying mechanisms of HCC metastasis. METHODS: Using MHCC97- a metastatic human hepatocellular carcinoma (HCC) cell line reported in 1999-as the parent cells, we subsequently established three cell lines (MHCC97-L, HMCC97-H, and HCCLM3) with increasing spontaneous metastatic potential. Now, the fourth cell line with unique multiple metastatic characteristics has been established by six rounds of in vivo selection. RESULTS: This cell line, designated as HCCLM6, is a polygonal epithelial cell with hypotriploid karyotype, the modal chromosomes are 55-58, and marker chromosomal abnormalities include i(1) (q10), i(8)(q10), der (4) t(4;8)(q31;q22), i(X)(q10). The cell population doubling time was 32 h. Fluorescent PCR showed HBV DNA integration in the cellular genome. Thirty-five days after HCCLM6 was injected subcutaneously into BALB/c nude mice, prominent lung metastases occurred in 100% of the recipient animals. When tumor tissue was orthotopically implanted into the liver of nude mouse, widespread loco-regional and pulmonary metastases occurred. Inoculation of this cell into the footpad of nude mice also produced 75% regional lymph node metastasis. Compared with MHCC97-L which was not metastastatic via subcutaneous or footpad inoculation and 40% metastatic via orthotopic inoculation, HCCLM6 had increased expression of matrix metalloproteinase (MMP-2 and MMP-9) and cytokeratin 19 (CK19), and decreased expression of Rb2/p130. The establishment of this new cell line has completed our stepwise metastatic HCC cell mode system, which was characterized by a similar genetic background but with significant differences in spontaneous metastasis behavior. CONCLUSIONS: The study supports the theory that cancer metastasis is a highly selective dynamic process and the cell model system could be a useful platform for the study of HCC metastasis.

Animals↗

PubMed2004

[Soluble expression of Plasmodium falciparum glutamate dehydrogenase in Escherichia coli, and its purification and identification].

OBJECTIVE: To make soluble expression of Plasmodium falciparum (FCC1/HN) glutamate dehydrogenase (GDH) in Escherichia coli, purification and immunocompetence identification of the recombinant non-fusion GDH. METHODS: The GDH gene was cloned into prokaryotic expression vector pET23 (a) to form recombinant expression vector pET23 (a)/GDH. pET23(a)/GDH was transformed into E. coli BL21 (DE3). Induced by IPTG (isopropyl-beta D-thiogalactoside), GDH was highly expressed in the supernatant after sonication. The soluble recombinant GDH was purified by Source-Q and Source-S chromatography. Enzyme-linked immunosorbent assay and Western blotting were carried out to identify the immunocompetence of the purified product. RESULTS: SDS-PAGE analysis showed that the soluble GDH protein accounted for approximately 15% of the total bacterial protein. By two-step ion-exchange chromatography, the purity of GDH reached more than 90% and the GDH possessed high antigenicity. CONCLUSION: The soluble expression of GDH results in an integral three-dimensional structure epitope with high biological activity.

Animals↗

PubMed2004

[Study on the inhibitory effect of small tripeptide CMS024 on tumor growth and metastasis in nude mice model of human hepatocellular carcinoma metastasis].

OBJECTIVE: This experiment was designed to study the effect of small molecule tripeptide CMS024 on tumor growth and metastasis in a nude mice model of human hepatocellular carcinoma (HCC) metastasis. METHODS: Highly metastatic human HCC cell strain HCCLM6 was injected into subcutaneous region of nude mice. When the subcutaneous tumor reached 0.8 cm in diameter, the tumor was removed and cut into small pieces about 1 mm in diameter and implanted orthotopically into the liver of 20 BALB/c nude mice, which were randomized into treatment group and control group each with 10 mice. The treatment group received daily CMS024 intraperitoneal injection at the dose of 300 microg/kg beginning from the second postoperative day. The control group received intraperitoneal injection of equal amount of 0.85% sodium chloride solution. The mice were observed for signs of disease development. Thirty-five days later, the mice were sacrificed and abdominal and pulmonary metastases were recorded and peripheral blood hematological and biochemical parameters were determined. RESULTS: After 35 days of intervention, all the 10 mice in the treatment group were alive and well, but there were only 9 living mice in the control group. The mean tumor weights were 1.9 g +/- 0.5 g in the treatment group and 2.3 g +/- 0.8 g in the control group (P > 0.05). The abdominal wall metastases and intraperitoneal metastases were 100% for the control group and only 60% and 50%, respectively, for the treatment group (P < 0.05). Bloody ascites and gross intrahepatic metastatic nodules were found in 70% and 90% of nude mice, respectively, for the control group, and 20% and 40%, respectively, for the treatment group (P > 0.05). The median number of grades I, II, III and IV pulmonary metastases were 92, 24, 15 and 16, respectively, for the control group, and 24, 20, 10 and 8, respectively, for the treatment group. There were statistically significant differences in the number of grade I pulmonary metastases between the treatment group and the control group (24 vs 92, P < 0.05). No statistically significant differences in the body weight, peripheral blood hematological and biochemical parameters were observed between the two groups. No toxic effects were observed during the observation period. CONCLUSIONS: Small molecule tripeptide CMS024 demonstrated positive effects to retard tumor growth and inhibit loco-regional and long distance metastases in a nude mice model of human HCC metastasis, and no obvious toxic or side effects on the tumor bearing nude mice.

Animals↗

PubMed2004

[The effect of IRESSA on H22 mouse hepatocellular carcinoma].

OBJECTIVE: To investigate the effect of IRESSA (gefitinib, ZD1839) on H22 murine hepatocellular carcinoma. METHODS: Mice bearing H22 hepatocellular carcinoma were randomly divided into oral control group, Normal saline (NS) control group, cisplatin (CDDP) d1-5 group, CDDP d6-10 group, IRESSA group, IRESSA combined with CDDP early (IRESSA + CDDP d1-5) group, and IRESSA combined with CDDP lately (IRESSA + CDDP d6-10) group. IRESSA was given by daily gastrogavage for 10 days (day 1-day 10) at 100 mg/kg in body weight (BW). CDDP was given by daily intraperitoneal injection for 5 days (day 1-day 5, or day 6-day 10) at 1.2 mg/kg in BW. The growth inhibiting rate (IR) of tumor, change of BW, spleen index (SI), and amounts of blood leucocyte or hemoglobin were detected. RESULTS: IR of tumor in IRESSA group was not significantly difference with that in CDDP d1-5 group, CDDP d6-10 group, IRESSA + CDDP d1-5 group (P > 0.05). IR of tumor in IRESSA group, CDDP d1-5 group, CDDP d6-10 group, IRESSA and IRESSA + CDDP d1-5 group were 41%, 54%, 46%, and 56%, respectively. IR of tumor in IRESSA + CDDP d6-10 group (26%) was significantly lower than that in CDDP d6-10 group (P < 0.05) or in IRESSA + CDDP d1-5 group (P < 0.01). Compared with oral or NS control groups, SI and net BW in IRESSA group was not significantly difference (P > 0.05). SI and net BW in both IRESSA + CDDP d1-5 group and IRESSA + CDDP d6-10 group were lower markedly than those in IRESSA group (P < 0.01). CONCLUSION: Tumor growth of H22 bearing mice was markedly inhibited by IRESSA.

Animals↗