Biomedical subjects

Ping Shen

Publications and source records attributed to Ping Shen.

At least 37 records · Page 2Linked to original sources

PubMed2005

Therapeutic effects of Lycium barbarum polysaccharide (LBP) on irradiation or chemotherapy-induced myelosuppressive mice.

AIM: The aim of this study was to investigate the effects of Lycium barbarum polysaccharide (LBP) on irradiation- or chemotherapy-induced myelosuppressive mice and cultured peripheral blood mononuclear cells (PBMCs). METHODS: In an in vivo experiment, mice were irradiated with a sublethal dose of 550 cGy X-ray or intraperitoneally (i.p.) injected with carboplatin (CB) 125 mg/kg to produce severe myelosuppression. Four to 6 hours after the irradiation or injection, mice were subcutaneously (s.c.) injected with LBP (50, 100, and 200 mg/kg) daily from day 0 to day 6. Blood samples were collected from the tail veins of mice at different time points, and peripheral white blood cells (WBC), red blood cells (RBC), and platelet (PLT) counts were monitored. In an in vitro experiment, human PBMCs were incubated with LBP at different concentrations in combination with phytohemagglutinin (PHA), and the production of granulocyte colony-stimulating factor (G-CSF) was tested. RESULTS: Compared to the control, 50 mg/kg LBP (LBP-L) significantly ameliorated the decrease of peripheral WBC of irradiated myelosuppressive mice on day 13, and 100 mg/kg LBP (LBP-M) did the same on days 17 and 21. All dosages of LBP significantly ameliorated the decrease of peripheral RBC of irradiated myelosuppressive mice on days 17 and 25. Two-hundred mg/kg LBP (LBP-H) and LBP-M significantly enhanced peripheral PLT counts of irradiated myelosuppressive mice on days 10, 13, 17, and 21, as did LBP-L on days 13 and 17. All dosages of LBP increased peripheral WBC counts of chemotherapy-induced myelosuppressive mice to some extent, but there was no statistic difference when compared to the control. LBP-H significantly ameliorated the decrease of peripheral RBC of chemotherapy-induced myelosuppressive mice on days 13, 15, 17, and 20, and LBP-M and LBP-L did the same on days 15 and 17. All dosages of LBP significantly enhanced peripheral PLT counts of chemotherapy-induced myelosuppressive mice on days 7 and 10, as did LBP-H on days 13, 15, and 17, and LBP-M on days 13 and 15. Also, LBP could obviously stimulate human PBMCs to produce G-CSF. CONCLUSIONS: LBP promoted the peripheral blood recovery of irradiation or chemotherapy-induced myelosuppressive mice, and the effects may be the result of the stimulation of PBMCs to produce G-CSF.

Animals↗

PubMed2005

[Impact of antipyretic and purgative herbs on intestinal mucosal barrier and inflammatory response in treatment of acute cholangitis in rats].

OBJECTIVE: To investigate the effects of antipyretic and purgative herbs on intestinal mucosal barrier and inflammatory response in the treatment of acute cholangitis. METHODS: Sixty SD rats were randomly divided into group A (untreated group, acute cholangitis was induced, n=20), group B (treatment group, acute cholangitis was induced and treated with antipyretic and purgative herbs, n=20) and group C (sham operation group, n=20). At the third or fifth day after operation, the rats were sacrificed and sampled. The serum endotoxin, cytokines and inflammatory mediators were tested and the numbers of labeled bacteria in the liver, spleen and mesenteric lymph nodes translocated from the gut were assayed. RESULTS: As compared with group A, the serum content of endotoxin, IL-6, IL-8, TNF-alpha, CRP and NO was significantly lower and that of IL-2 was significantly higher, and the translocated numbers of labeled bacteria from gut were reduced in both group B and group C (P<0.01). CONCLUSION: Antipyretic and purgative herbs can play therapeutic roles in the treatment of acute biliary tract infections, including the protection of intestinal mucosal barrier from bacterial translocation, reduction of serum endotoxin content and regulation of inflammatory response.

Acute Disease↗

PubMed2005

[Load of calcium probe Fura -2/AM in Escherichia coli cells].

The fluorescence characteristics of Fura-2/AM, a kind of calcium probe normally used in analysis of animal cells, were studied in detail in this work. The load of the probe into Escherichia coli cells was elucidated through fluorescence spectra. The combination of Fura-2 with calcium ions inside Escherichiacoli cells was observed, and the transmembrane behaviors of extracellular calcium to Escherichia coli cells were also investigated. The work was aimed at further researches on the calcium-induced horizontal gene transfer in Escherichia coli cells.

Calcium↗

PubMed2004

Tumor type M2 pyruvate kinase expression in gastric cancer, colorectal cancer and controls.

AIM: Tumor formation is generally linked to an expansion of glycolytic phosphometabolite pools and aerobic glycolytic flux rates. To achieve this, tumor cells generally overexpress a special glycolytic isoenzyme, termed pyruvate kinase type M(2). The present study was designed to evaluate the use of a new tumor marker, tumor M(2)-PK, in discriminating gastrointestinal cancer patients from healthy controls, and to compare with the reference tumor markers CEA and CA72-4. METHODS: The concentration of tumor M(2)-PK in body fluids could be quantitatively determined by a commercially available enzyme-linked immunosorbent assay (ELISA)-kit (ScheBo Tech, Giessen, Germany). By using this kit, the tumor M(2)-PK concentration was measured in EDTA-plasma of 108 patients. For the healthy blood donors a cut-off value of 15 U/mL was evaluated, which corresponded to 90% specificity. Overall 108 patients were included in this study, 54 patients had a histological confirmed gastric cancer, 54 patients colorectal cancer, and 20 healthy volunteers served as controls. RESULTS: The cut-off value to discriminate patients from controls was established at 15 U/mL for tumor M(2)-PK. The mean tumor M(2)-PK concentration of gastric cancer was 26.937 U/mL. According to the TNM stage system, the mean tumor M(2)-PK concentration of stage I was 16.324 U/mL, of stage II 15.290 U/mL, of stage III 30.289 U/mL, of stage IV 127.31 U/mL, of non-metastasis 12.854 U/mL and of metastasis 35.711 U/mL. The mean Tumor M(2)-PK concentration of colorectal cancer was 30.588 U/mL. According to the Dukes stage system, the mean tumor M(2)-PK concentration of Dukes A was 16.638 U/mL, of Dukes B 22.070 U/mL, and of Dukes C 48.024 U/ml, of non-metastasis 19.501 U/mL, of metastasis 49.437 U/mL. The mean tumor M(2)-PK concentration allowed a significant discrimination of colorectal cancers (30.588 U/mL) from controls (10.965 U/mL) (P<0.01), and gastric cancer (26.937 U/mL) from controls (10.965 U/mL) (P<0.05). The overall sensitivity of tumor M(2)-PK for colorectal cancer was 68.52%, while that of CEA was 43.12%. In gastric cancer, tumor M(2)-PK showed a high sensitivity of 50.47%, while CA72-4 showed a sensitivity of 35.37%. CONCLUSION: Tumor M(2)-PK has a higher sensitivity than markers CEA and CA72-4, and is a valuable tumor marker for the detection of gastrointestinal cancer.

Biomarkers, Tumor↗

PubMed2004

Exploring the mechanism of competence development in Escherichia coli using quantum dots as fluorescent probes.

The mechanism of divalent Ca2+ cation induction of Escherichia coli competence is still not fully understood, though it is a common method for introducing recombinant DNA into bacterial cells in gene engineering. Quantum dots (QDs), as a new fluorescent probe of being applied in biology research, have aroused great interest. In this paper, we explored the mechanism of E. coli competence development using QDs for the first time. Results showed that water-soluble QDs of diameter 3-4 nm could go into competent cells, but could not enter noncompetent cells. This result was further confirmed using atomic force microscopy and DNA transforming experiments, suggesting that nonphysiological, high concentrations of Ca2+ enhanced the penetrability of cell membranes so that QDs, which cannot enter cells normally due to their greater diameter (3-4 nm), can do so easily into competent cells. Therefore, we believe that, at least for E. coli, the mechanism of Ca2+-induced competence development is mediated physicochemically rather than physiologically.

Biochemistry↗

PubMed2004

Cloning and analysis of WF146 protease, a novel thermophilic subtilisin-like protease with four inserted surface loops.

Cloning and sequencing of the gene encoding WF146 protease, an extracellular subtilisin-like protease from the thermophile Bacillus sp. WF146, revealed that the WF146 protease was translated as a 416-amino acid precursor consisting of a putative 18-amino acid signal peptide, a 10-kDa N-terminal propeptide and a 32-kDa mature protease region. The mature WF146 protease shares a high degree of amino acid sequence identity with two psychrophilic subtilisins, S41 (68.2%) and S39 (65.4%), and a mesophilic subtilisin, SSII (67.1%). Significantly, these closely related proteases adapted to different temperatures all had four inserted surface loops not found in other subtilisins. However, unlike those of S41, S39 and SSII, the inserted loops of the WF146 protease possessed stabilizing features, such as the introduction of Pro residues into the loop regions. Interestingly, the WF146 protease contained five of the seven mutations previously found in a hyperstable variant of subtilisin S41 obtained by directed evolution. The proform of WF146 protease (pro-WF146 protease) was overexpressed in Escherichia coli in an inactive soluble form. After heat treatment, the 42-kDa pro-WF146 protease converted to a 32-kDa active mature form by processing the N-terminal propeptide. The purified mature WF146 protease hydrolyzed casein with an optimum temperature of 85 degrees C, and lost activity with a half-life of 30 min at 80 degrees C in the presence of 10 mM CaCl2.

Amino Acid Sequence↗

PubMed2004

Study on biological effect of La3+ on Escherichia coli by atomic force microscopy.

The biological effects of rare-earth metal ions on the organism have been studied using La3+ as a probe ion and Escherichia coli cell as a target organism. Atomic force microscopy (AFM) studies reveal that La3+ substantially changes the structure of the outer cell membrane responsible for the cell permeability. Significant damages of the outer cell membrane are observed using scanning electron microscopy (SEM) after the introduction of La3+. In result, the cell becomes easily attacked by lysozyme. Moreover, inductively coupled plasma-mass spectrometry (ICP-MS) measurements show considerable amount of Ca2+ and Mg2+ in the supernatant from the La3+ exposed cells. It is proposed that La3+ can replace Ca2+ from the binding sites because of their close ionic radii and similar ligand specificities. Lipopolysaccharide (LPS), which forms the outer membrane of Gram-negative bacteria, could not serve as the cellular envelope steadily after Ca2+ and Mg2+ released from their binding sites on the LPS patches.

Calcium↗

PubMed2004

Melanin pigment formation and increased UV resistance in Bacillus thuringiensis following high temperature induction.

The pigment melanin is well known to protect against the damaging effects of UV radiation. In this study, we show that thirty-five of thirty-seven tested Bacillus thuringiensis strains possess the potential to produce melanin in the presence of L-tyrosin at elevated temperature (42 degrees C). These findings offer a method of protecting insecticidal toxins produced by B. thuringiensis from UV degredation and may therefore have important applications in the field of crop protection. Toxicity assays on Heliothis armigera suggested that the insecticidal activity of B. thuringiensis that produced melanin was significantly higher after UV irradiation than when melanin was not produced.

Animals↗

PubMed2003

Developmental control of foraging and social behavior by the Drosophila neuropeptide Y-like system.

Animals display stereotyped behavioral modifications during development, but little is known about how genes and neural circuits are regulated to turn on/off behaviors. Here we report that Drosophila neuropeptide F (dNPF), a human NPY homolog, coordinates larval behavioral changes during development. The brain expression of npf is high in larvae attracted to food, whereas its downregulation coincides with the onset of behaviors of older larvae, including food aversion, hypermobility, and cooperative burrowing. Loss of dNPF signaling in young transgenic larvae led to the premature display of behavioral phenotypes associated with older larvae. Conversely, dNPF overexpression in older larvae prolonged feeding, and suppressed hypermobility and cooperative burrowing behaviors. The dNPF system provides a new paradigm for studying the central control of cooperative behavior.

Age Factors↗

PubMed2003

A novel boundary element may facilitate independent gene regulation in the Antennapedia complex of Drosophila.

The intrinsic enhancer-promoter specificity and chromatin boundary/insulator function are two general mechanisms that govern enhancer trafficking in complex genetic loci. They have been shown to contribute to gene regulation in the homeotic gene complexes from fly to mouse. The regulatory region of the Scr gene in the Drosophila Antennapedia complex is interrupted by the neighboring ftz transcription unit, yet both genes are specifically activated by their respective enhancers from such juxtaposed positions. We identified a novel insulator, SF1, in the Scr-ftz intergenic region that restricts promoter selection by the ftz-distal enhancer in transgenic embryos. The enhancer-blocking activity of the full-length SF1, observed in both embryo and adult, is orientation- and enhancer-independent. The core region of the insulator, which contains a cluster of GAGA sites essential for its activity, is highly conserved among other Drosophila species. SF1 may be a member of a conserved family of chromatin boundaries/insulators in the HOM/Hox complexes and may facilitate the independent regulation of the neighboring Scr and ftz genes, by insulating the evolutionarily mobile ftz transcription unit.

Animals↗

PubMed2003

Characterization of a novel plasmid from extremely halophilic Archaea: nucleotide sequence and function analysis.

We determined the complete nucleotide sequence of the 16341 bp plasmid pHH205 of the extremely halophilic archaeon Halobacterium salinarum J7. The plasmid has a G+C content of 61.1%. A number of direct and inverted repeat sequences were found in pHH205, while no insertion sequences were found. Thirty-eight large open reading frames (ORFs) were identified in both strands, and most of them had no significant similarities to known proteins. A putative protein encoded by ORF31 showed 20-41% homology to some hypothetical proteins, which are annotated in several archaeal genome databases as predicted nucleic acid-binding proteins containing PIN domain. Sequence analysis using the GC skew procedure predicted a possible origin of replication. A 4.8 kb PvuII-SnaBI fragment containing both this region and ORF31 was shown to be able to restore replicate of pWL102, a replicon-deficient plasmid in Haloferax volcanii and in H. salinarum R1. Several methods failed to completely cure H. salinarum J7 of pHH205, suggesting that the plasmid probably played an important role in the growth and metabolism of the host. Our work describes a novel haloarchaeal replicon, which may be useful in the construction of cloning and shuttle vectors.

Archaeal Proteins↗

PubMed2003

The 492-bp RM07 DNA fragment from the halophilic Archaea confers promoter activity in all three domains of life.

A 492-bp DNA fragment, designated RM07, was isolated from the chromosomal DNA of the halophilic Archaea, Halobacterium halobium, and was shown to confer promoter activity in Escherichia coli. Sequence analysis revealed that RM07 contained three consensus sequences of the archaeal distal promoter element as well as the typical -35 and -10 box sequences of bacterial promoters. Promoter probe analysis confirmed that RM07 conferred promoter activity in all three domains of life: Archaea (Haloferax volcanii), Eukarya (Saccharomyces cerevisiae) and Bacteria (Escherichia coli). Deletion analysis and site-directed mutagenesis further identified the functional regions within RM07 required for promoter activity. This is the first report of a DNA fragment from Archaea that confers promoter activity in all three domains of life, suggesting that the promoter structure and activity may be viewed as a bridge narrowing the gaps among the different domains of life.

Artificial Gene Fusion↗

PubMed2003

Steroidal saponins from rhizomes of Tupistra wattii Hook. f.

Chemical examination of the fresh rhizomes of Tupistra wattii HOOK. f. led to the isolation of three new steroidal saponins, wattoside G (1), H (2), and I (3), together with one known steroidal saponin, (25S)-1beta,3beta,4beta-trihydroxyspirotan-5beta-yl-O-beta-D-glucopyranoside (4). The structures of 1-3 were established to be (25R)-1beta,2beta,3beta,5beta-tetrahydroxyspirostan-4beta-yl-O-beta-D-xylopyranoside (1), (24S,25S)-24-[(beta-D-glucopyranosyl)oxy]-1beta,2beta,3beta,4beta,5beta,7beta-hexahydroxyspirostan-6-one (2), and (24S,25S)-1beta,3beta-dihydroxy-5beta-spirostan-24-yl-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (3) on the basis of detailed analyses of physical, chemical, and spectral data. The isolated compounds were evaluated for cytotoxic activity against the cancer cell line K562 in vitro.

Humans↗

PubMed2003

[Experimental study on effects of herbs for nourishing and smoothing the liver in reversing bile lithogenicity of guinea pig].

OBJECTIVE: To further probe the mechanisms of herbs for nourishing and smoothing the liver in reversing bile lithogenicity of guinea pig. METHODS: Sixty guinea pigs were divided randomly into control group (fed with normal diet, n=20), model group (fed with lithogenic diet, n=20) and treatment group (fed with lithogenic diet plus herbal medicine, n=20). After four-week feeding, the animals were sacrificed and sampled, the rates of gallstone formation in each group were estimated, and the total bile acid (TBA), total bilirubin (TBIL), conjugated bilirubin (CB), unconjugated bilirubin (UCB), and calcium ion in the bile were determined, and the different bilirubins were analyzed by HPLC. RESULTS: (1) The rate of gallstone formation was 5% in normal group, 81.25% in model group and 31.25% in treatment group (P<0.05). (2) The bile TBIL, CB, UCB and Ca(2+) were higher and the bile TBA was lower significantly in model group than that in the other two groups (P<0.05). (3) HPLC analysis revealed that MCB was higher and DCB was lower significantly in model group (P<0.01), and there were no significant differences of UCB and IPA among the three groups. (4) The percentages of MCB and UCB were much higher and the percentage of DCB was remarkably lower in model group (P<0.05). CONCLUSION: Herbs for nourishing and smoothing the liver can significantly reduce the rate of gallstone formation and has effect of reversing lithogenicity of bile in guinea pigs fed with lithogenic diet.

Animals↗

PubMed2003

The pathogenesis of Chlamydia pneumoniae-type pneumonitis in mice.

OBJECTIVE: To evaluate mice as experimental animals for Chlamydia pneumoniae (C. pneumoniae) infection and investigate the pathogenesis of C. pneumoniae derived pneumonitis. METHODS: Icr mice were inoculated with the C. pneumoniae strain, CWL-029, either intranasally or intravenously. After a single dose inoculation, mice were killed on the 1st, 3rd, 7th, 14th, 21st, 28th and 60th days. The pathological changes in lung tissue were analyzed. RESULTS: The Icr mice were shown to be susceptible to C. pneumoniae. Inoculation into mice with C. pneumoniae induced a prolonged course of lung infection, as demonstrated by persistence of lung pathology (up to 60 days). Via intranasal inoculation of mice, lung pathology was characterized by patchy interstitial pneumonitis with predominantly neutrophil leukocyte infiltration early (within the first 7 days) and lymphocyte infiltration in the later stages (14 days later) of infection. After intravenous inoculation, a similarly developed interstitial pneumonitis was observed, but it was milder and patchier, especially in early stages. C. pneumoniae DNA was detected by polymerase chain reaction (PCR) intermittently in the lung tissue. Inoculated mice developed serum IgG antibody responses. CONCLUSION: The Icr mice were susceptible to C. pneumoniae, resulting in a pulmonary infection characterized by interstitial pneumonitis, occurring most strongly via intranasal inoculation.

Animals↗

PubMed2003

[Horizontal gene transfer].

In this paper the conception of horizontal gene transfer (HGT) was introduced,and main mode of HGT was also enumerated as follows: HGT by medium such as plasmid and virus etc., and the HGT without any medium. The transfer of genes from one species to another especially between remote species was emphasized by the information from genome sequencing. The problems about evolution phylogenies and safety of GEMs (gene engineered microorganisms) for HGT were discussed.

English Abstract↗

PubMed2002

Characterization of a functional neuropeptide F receptor from Drosophila melanogaster.

Potential receptors for Drosophila neuropeptide F (DmNPF) were identified in the genome database. One receptor (DmNPFR1) sequence resembled the Lymnaea NPY receptor, an invertebrate homolog of the vertebrate Y-receptor family. DmNPFR1 was cloned and tested for functionality in stably transfected mammalian CHO cells. In whole cell binding assays, DmNPF displaced 125I-NPF in a concentration-dependent manner (IC(50) = 65 nM). DmNPF inhibited forskolin-stimulated adenylyl cyclase activity similarly (IC(50) = 51 nM). Whole-mount in situ hybridization revealed that DmNPFR1 RNA is expressed in CNS and midgut of Drosophila larvae. DmNPFR1, a new invertebrate Y-receptor homolog, apparently is a functional receptor for DmNPF.

Adenylyl Cyclases↗

PubMed2002

A new ergostanol saponin from Dioscorea deltoidea Wall var. orbiculata.

From the fresh rhizomes of Dioscorea deltoidea Wall var. orbiculata, a novel ergostanol saponin, orbiculatoside A (1), was isolated and identified as 3-O-beta-D-glucopyranosyl-ergost-5-ene-3beta, 26-diol-26-O-beta-D-glucopyranosyl(1-->3)-[beta-D-glucopyranosyl(1-->2)-beta-D-glucupyranosyl(1-->6)]-beta-D-glucopyranoside by various NMR techniques in combination with chemical methods. The new saponin showed strong activity against Pyricularia oryzae, with a MMDC (minimum morphological deformation concentration) value of 28.04 micromol/l and was cytotoxic to cancer cell line K562, HCT-15, A549, HT1080, and A2780a in vitro.

Antineoplastic Agents↗