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Biomedical subjects

Ning Liu

Publications and source records attributed to Ning Liu.

At least 37 records · Page 2Linked to original sources
PubMed2006

Simulation of single molecule inelastic electron tunneling signals in paraphenylene-vinylene oligomers and distyrylbenzene[2.2]paracyclophanes.

Inelastic resonances in the electron tunneling spectra of several conjugated molecules are simulated using the nonequilibrium Greens function formalism. The vibrational modes that strongly couple to the electronic current are different from the infrared and Raman active modes. Spatially resolved inelastic electron tunneling (IET) intensities are predicted. The simulated IET intensities for a large distyrylbenzene paracyclophane molecule are in qualitative agreement with recent experimental results.

Journal Article↗
PubMed2006

A sperm component, HSD-3.8 (SPAG1), interacts with G-protein beta 1 subunit and activates extracellular signal-regulated kinases (ERK).

HSD-3.8 cDNA (accession number AF311312) encodes a human sperm component. A 0.7 kb fragment (HSD-0.7) containing three immunological epitopes of HSD-3.8 cDNA was prepared and expressed in E. coli. Immunization of female rats with the recombinant HSD-0.7 proteins induced infertility. A cDNA fragment encoding the C-terminal 144 amino acids of human G-protein beta l subunit (Gbeta1-C144) was screened by yeast two-hybrid, when HSD-0.7 segment was used as a bait. Recombinant His6-tagged-Gbeta1-C144 protein was expressed in E. coli BL21 and Anti-Gbeta1 serum was raised with purified Gbeta1-C144. HA-tagged HSD-0.7 and FLAG-tagged Gbeta1 plasmids were constructed and co-transfected into human embryonal kidney 293 cells. Two proteins were localized at superimposable sites in the cytoplasm, and they formed a complex when 500 micromol/L GDP existed. Overexpression of HSD-0.7 activated the G-protein-mediated extracellular signal-regulated kinases (ERK1/2); however, the truncated fragments of HSD-0.7, which lacked either TPR domain or P-loop, lost the ability to activate the ERK1/2 pathway. Further study revealed that the activation of ERK1/2 was protein kinase C (PKC) rather than Ras dependent. These results provide evidence that HSD-3.8 present in spermatocytes and sperm may participate in spermatogenesis and fertilization process by activating the PKC-dependent ERK1/2 signal transduction pathway.

Animals↗
PubMed2006

A high-precision voltage source for EIT.

Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. EIT can be performed by applying currents through the electrodes and measuring the electrode voltages or by applying electrode voltages and measuring the currents. Techniques have also been developed for applying the desired currents using voltage sources. This paper describes a voltage source for use in applied-voltage EIT that includes the capability of measuring both the applied voltage and applied current. A calibration circuit and calibration algorithm are described which enables all voltage sources in an EIT system to be calibrated to a common standard. The calibration minimizes the impact of stray shunt impedance, passive component variability and active component non-ideality. Simulation data obtained using PSpice are used to demonstrate the effectiveness of the circuits and calibration algorithm.

Calibration↗
PubMed2006

Prognostic factors of young patients with colon cancer after surgery.

AIM: To investigate the prognostic factors of 96 young patients with colon cancer within a cancer center by univariate and multivariate analysis. METHODS: A total of 723 patients with colon cancer were treated surgically during a period of 10 years. Ninety six of them were 40 years old or younger.R0, R1 and R2 operations were performed in 69 (71.9%), 4(4.1%) and 23 patients(24%), respectively. Left hemicolectomy was performed in 43 patients, right hemicolectomy in 37 patients, transverse colon resection in 9 patients and low anterior resection in 7 patients. Cox multivariate regression analysis was performed to identify predictors of survival. RESULTS: The operation mortality was 0%, 54 patients died within 111 mo after operation due to occurrence or metastases of the tumor. Liver,lung and bone metastases occurred in 3, 1 and 5 patients, respectively. The mean survival time for all patients was 77.9 +/- 5.01 mo and the overall 3-,5- and 10- year survival rates were 66.68%, 58.14% and 46.54%, respectively. In the univariate survival analysis,patient age,type of operation, radical resection, blood transfusion, histological type, diameter of tumor,depth of tumor invasion, lymphatic invasion, distant metastases, liver metastases and TNM stage were found to be predictors of survival in young patients with colon cancer. In the Cox-regression analysis,blood transfusion and lymphatic invasion were determined as independent prognostic factors of survival. CONCLUSIONS: Age, type of operation, radical resection, blood transfusion, histological type, diameter of tumor,depth of tumor invasion, lymphatic invasion, distant metastasis and TNM stage are the predictors of survival in young patients with colon cancer after surgery.

Adult↗
PubMed2006

Construction of a novel chimera consisting of a chelator-containing Tat peptide conjugated to a morpholino antisense oligomer for technetium-99m labeling and accelerating cellular kinetics.

The attempt to target the limited copies of messenger RNA (mRNA) in vivo with radiolabeled nucleobase oligomers as antisense probes is challenging. Selecting an antisense molecule with superior properties, enhancing the cellular kinetics, and improving the radiolabeling chemistry would be the reasonable approach to accomplish this goal. The present study reports a method to construct a chimera of phosphorodiamidate morpholino nucleobase oligomer (MORF) covalently conjugated to a peptide containing a cell membrane transduction Tat peptide and an N(2)S(2) chelator for technetium-99m ((99m)Tc) radiolabeling (N(2)S(2)-Tat-MORF). The radiolabeling properties and cellular kinetics of (99m)Tc-N(2)S(2)-Tat-MORF were measured. As hypothesized, the preparation of (99m)Tc-N(2)S(2)-Tat-MORF could be achieved by an instant one-step method with labeling efficiency greater than 95%, and the (99m)Tc-N(2)S(2)-Tat-MORF showed distinct properties in cell culture from those of a control, the same MORF sequence without Tat but with mercaptoacetyltriglycine (MAG(3)) as chelator for (99m)Tc ((99m)Tc-MAG(3)-MORF). (99m)Tc-N(2)S(2)-Tat-MORF achieved maximum accumulation of about 35% within 2 h, while (99m)Tc-MAG(3)-MORF showed lower and steadily increasing accumulations but of less than 1% in 24 h. These preliminary results demonstrated that the proposed chimera has properties for easy labeling, and (99m)Tc-N(2)S(2)-Tat-MORF prepared by this method possesses enhanced cellular kinetics and merits further investigation for in vivo mRNA targeting.

Chelating Agents↗
PubMed2006

[Efficacy of FAEV regimen in treatment of high-risk drug-resistant gestational trophoblastic tumor].

OBJECTIVE: To evaluate the efficacy of floxuridine, actinomycin D, etoposide, vincristine (FAEV) regimen in treatment of high-risk drug-resistant gestational trophoblastic tumor (GTT). METHODS: From October 2001 to May 2004, 11 cases of high-risk drug-resistant GTT were treated with FAEV regimen. The International Federation of Gynecology and Obstetrics (FIGO) prognosis score (2000) was 7 to 13 (median 9). All patients were referred to Peking Union Medical College Hospital because of failure of chemotherapy previously. After the FAEV treatment, they were followed up for 15 to 42 months. RESULTS: Seven cases (64%, 7/11) were cured by FAEV regimen. The median treatment course for serum human chorionic gonadotropin reaching normal level was 3. Four cases (36%, 4/11) showed drug-resistant to FAEV regimen. The major side effect of FAEV regimen was myelosuppression. Granulocyte colony stimulating factor support was needed after 98% (63/64) of the courses. CONCLUSION: For those high-risk drug-resistant GTT cases, FAEV regimen could be considered as an effective choice of treatment.

Adult↗
PubMed2006

[Determination of istanbulin A in Sarcandra glabra].

OBJECTIVE: To determine istanbulin A in Sarcandra glabra (Thunb.) Nakai. METHODS: An RP-HPLC method was established and an hypersil ODS C18 column (4.6 mm x 200 mm, 5 microm) was used. The detective wavelength was at 218nm. RESULTS: Istanbulin A had a good linearity in the range of 0. 135 to approximately 2. 16 microg. The recovery rate was 98.54%. CONCLUSION: This method is simple, accurate and repeatable. It can be used to determine istanbulin A in Sarcandra glabra.

Chromatography, High Pressure Liquid↗
PubMed2006

[Effects of TGF-beta1, gene modified donor dendritic cells on immune repulsion].

OBJECTIVE: To examine the inhibitory action of the injection of TGF-beta1 gene modified donor dendritic cells (TGF-beta1-DC) on the immune repulsion in rat liver transplantation and detect the related mechanism. METHODS: The recombinant TGF-beta1-pcDNA3 adenovirus transfected Wistar DCs were injected into the tail vein of the recipient SD rat. One week later, the rat immune repulsion model of liver transplantation was set up, the expression of TGF-beta1 gene was identified, and the survival was observed and recorded. The NF-kappaB activity and cell factor TNF of T cells in recipient spleen and Kupffer cells were detected by electrophoretic mobility shift assay and immunohistochemistry respectively. The pathological rejection index after transplantation was assayed. RESULTS: The rejection index was decreased and the survival time was prolonged in Ad-TGF-beta1-DC group as compared with those in control groups. Also it was found that TGF-beta1-DC injection inhibited the expression of NF-kappaB and TNF of T cells and Kupffer cells in rat liver allografts, and all differences were statistically significant. CONCLUSION: TGF-beta1 gene modified DC could obviously inhibit the activation of T cells and Kupffer cells, enhance the tolerogenicity of liver transplantation and prolong survival time.

Adenoviridae↗
PubMed2006

[Clinical analysis of fallopian tube prolapse after hysterectomy].

OBJECTIVE: To investigate the clinical diagnosis, treatment and prevention of fallopian tube prolapse (FTP) after hysterectomy. METHODS: A total of 7949 patients received hysterectomy from 1983 to Aug 2005 in Peking Union Medical College Hospital, including 6229 cases of trans-abdominal hysterectomy (TAH), 780 cases of transvaginal hysterectomy (TVH), and 940 cases of laparoscopic assisted vaginal hysterectomy (LAVH). Nine cases (including 1 case from other hospital) of FTP after hysterectomy were analyzed retrospectively for their symptoms, diagnosis and treatment. All of them were diagnosed according to the results of histology and follow-up. RESULTS: The overall incidence of FTP after hysterectomy was 0.11% (9/7949). Incidence of FTP after trans-abdominal hysterectomy was 0.08% (5/6229), after vaginal hysterectomy 0.51% (4/780), and after laparoscopic assisted vaginal hysterectomy 0 (0/940). There were no symptoms in 3 cases, but the other 6 cases had symptoms. The pelvic examination revealed the typical prolapsed fimbrial end of a fallopian tube in 3 cases and red granulation tissue in the other 6 cases. All of them were excised vaginally and cauterized. The results were confirmed by histological examination. No recurrent cases were reported in follow up. CONCLUSIONS: FTP is a rare complication after hysterectomy. The prognosis is well after proper diagnosis and treatment. Salpingectomy or fixation of accessories into the pelvic wall and complete peritonealisation at the time of hysterectomy are important methods to prevent FTP after hysterectomy.

Adult↗
PubMed2006

[Study on combined gene therapy for malignant gliomas transfected with antisense hTERT/PTEN in vitro and in vivo].

OBJECTIVE: To study inhibitory efficacy of combined gene therapy for malignant gliomas transfected with antisense human telomerase reverse transcriptase (hTERT)/PTEN in vitro and in vivo. METHODS: To construct two adenovirus recons which contained antisense hTERT and wild-type PTEN respectively with high performance homologous recombination system in bacteria. The two adenovirus recons were transfected into U251 human malignant glioma cells combinedly or respectively in vitro and in vivo. U251 cell proliferation in vitro was determined by MTT assay and flow cytometry, tumor growth in vivo was measured by the volume of glioma in nude mice. Telomerase activity was detected by telomeric repeat amplification protocol (TRAP) assay. Expression of hTERT and PTEN protein was detected by Western blotting methods. RESULTS: After transfection in vitro, the growth of U251 cells was inhibited significantly. The inhibitory effect was time-dependent. The strongest inhibition was observed in combined transfection group, at the 6th day, the survival rate was 37.6%, telomerase activity (only 28.8TPG) was inhibited significantly, hTERT protein expression was inhibited significantly too, which was 0.2106, but PTEN protein expression was increased significantly, which was 0.9630. In vivo, the growth of tumors was also effectively inhibited. CONCLUSION: Growth of malignant glioma cells is effectively inhibited after transfection with combined antisense hTERT and PTEN in vitro and in vivo.

Adenoviridae↗
PubMed2006

[Isolation, classification and antimicrobial activity of endophytic actinomycetes from plant leaves].

Leave samples of Paeonia lactiflora and Trifalium repens were collected from Sichuan Province and Beijing respectively to study their endophytic actinmycetes. After a well-established surface-sterilized procedure, the samples were plated on agar media of TWYE, HV, YECD, NA and WA, followed by incubation at 28 degrees C for 2 - 4 weeks. With the help of light microscope, 15 actinomycetes strains were isolated from the plates. Comparison of cultural features and fingerprinting analyses of BOX-PCR products were performed to cluster the isolates, with the result that all the strains were assigned to 12 different genotypes, half of them from Paeonia lactiflora and half from Trifalium repens. A combination of morphological and 16S rRNA gene sequence data showed that except strains C4 and C5, which belonged to Pseudonocardia, 13 of the isolates were streptomycetes. Most isolates share high 16S rRNA gene sequence similarities to known type strains. However, strain C12 shares low values, 96.6% in maximum, and strain C5 shares 97.9% in maximum; more assays are needed to ascertain their taxonomic positions. In the tests of antimicrobial activity against 7 bacteria, 3 fungi and 1 yeast, 11 isolates were positive in one or more tests, and 55% of the positive ones could inhibit the growth of Rhizoctonia solani, a significant pathogen of plants.

Actinobacteria↗
PubMed2005

Identification and molecular characterization of a peritrophin-like protein from fleshy prawn (Fenneropenaeus chinensis).

Peritrophin, one of the components of the peritrophic matrix, was first isolated from the intestine of insects. It is thought to protect insects from invasion of microorganisms and to stimulate digestion of food. Peritrophin-like proteins have also been found in crustaceans, as a component of the egg layer. In this study, one fragment of the peritrophin-like gene was obtained from fleshy prawn (Chinese shrimp) (Fenneropenaeus chinensis) by panning the T7 phage display library constructed with the shrimp hemocyte cDNA. The total sequence of the peritrophin cDNA was cloned by modified SMART cDNA and LD-PCR methods. The full cDNA is 1048bp and the deduced protein is composed of 274 amino acids, including 21 amino acid signal peptide, and four peritrophin A domains and the latter three forming three chitin-binding domains. Similarity analysis results showed that the peritrophin-like protein from F. chinensis has significant similarities with peritrophin-like and cortical rod proteins from other shrimp. It was inducing expression in hemocytes, heart, stomach, gut, and gills of the infected shrimp, and constitutive expression in the ovaries. No expression signal was detected in the hepatopancreas of either infected or noninfected shrimp. The recombinant peritrophin-like protein has the activity of binding Gram-negative bacteria and strong binding activity to chitin. Therefore, the bacteria and chitin binding activities of the peritrophin-like protein suggest that it may plays a role in immune defense and other physiological resposes.

Amino Acid Sequence↗
PubMed2005

Influence of a Chinese crude drug on Ca2+ influx and efflux in rat visceral organs: investigation and evaluation by 45Ca.

The influences of a Chinese crude drug, Herba Epimedii, (HE), on Ca2+ influx and efflux in the isolated rat aorta and some visceral organs were evaluated by using 45Ca as a radioactive tracer. Additionally, its protective effect on myocardial ischemia was investigated in live animals. The results indicated that HE has significant influence on Ca2+ influx and efflux in the isolated rat aorta, heart, and kidney, in that it can markedly block 45Ca entering into cell and can facilitate efflux of intracellular Ca2+. However, among the three kinds of extracts from HE, the alkali extracts have the most obvious effect on calcium channels in visceral organs. Even if the alkali extracts are diluted by water for 10 times, the material still has a rather strong inhibition effect on calcium channels. Fortunately, the three kinds of extracts have favorable protective effect on myocardial ischemia induced by drugs or by the ligation of the coronary artery. This is consistent with the results about the Ca2+ influx and efflux obtained by isotope tracer technique, and implies that the Chinese crude drug has attractive potential for the treatment of heart, cerebrovascular and other diseases.

Animals↗
PubMed2005

PKCdelta protects human breast tumor MCF-7 cells against tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces apoptosis in a number of tumorogenic or transformed cells, yet is relatively non-toxic to most normal cells, therefore, it is a promising agent for cancer therapy. However, some cancer cell lines were resistant to TRAIL cytoxicity, including MCF-7 breast cancer cells. The mechanism is not clear. Here, we report that protein kinase C delta (PKCdelta) protects MCF-7 cells from the recombinant soluble TRAIL (rsTRAIL)- mediated apoptosis. It was demonstrated that rottlerin, a PKCdelta inhibitor, sensitized MCF-7 cells to rsTRAIL cytoxicity. Combination of rottlerin and rsTRAIL inhibited PKCdelta translocation from the cytosol to membrane, and PKCdelta kinase activity on the cell membrane was kept pace with the change of PKCdelta expression. Moreover, inhibition of PKCdelta by interference RNA could facilitate apoptosis of MCF-7 cells induced by rsTRAIL. Further experiments on the signal machinery showed that rottlerin increased the sensitivity of MCF-7 cells to rsTRAIL by suppressing the transcription activity of NF-kappaB, and enhancing the caspase-processing to generate executive apoptotic signals. These findings indicate that PKCdelta functions as a survival factor protecting MCF-7 cells from the apoptosis induced by rsTRAIL.

Acetophenones↗
PubMed2005

Catalytic adsorptive stripping voltammetric determination of copper(II) on a carbon paste electrode.

A catalytic adsorptive stripping voltammetric method for the determination of copper(II) on a carbon paste electrode (PCE) in an alizarin red S (ARS)-K2S2O8 system is proposed. In this method, copper(II) is effectively enriched by both the formation and adsorption of a copper(II)-ARS complex on the PCE, and is determined by catalytic stripping voltammetry. The catalytic enhancement of the cathodic stripping current of the Cu(II) in the complex results from a redox cycle consisting of electrochemical reduction of Cu(II) ion in the complex and subsequent chemical oxidation of the Cu(II) reduction product by persulfate, which reduces the contamination of the working electrode from Cu deposition and also improves analytical sensitivity. In Britton-Robinson buffer (pH 4.56+/-0.1) containing 3.6 x 10(-5) mol L(-1) ARS and 1.6 x 10(-3) mol L(-1) K2S2O8, with 180 s of accumulation at -0.2 V, the second-order derivative peak current of the catalytic stripping wave was proportional to the copper(II) concentration in the range of 8.0 x 10(-10) to approximately 3.0 x 10(-8) mol L(-1). The detection limit was 1.6 x 10(-10) mol L(-1). The proposed method was evaluated by analyzing copper in water and soil.

Adsorption↗
PubMed2005

Gender effect on the right-left discrimination task in a sample of heroin-dependent patients.

RATIONALE: Discriminating right from left is an everyday cognitive ability. Repeated exposure to certain drugs, such as heroin, can produce poor performance on many cognitive tasks. However, it is yet unclear whether drug abuse impairs the ability of right-left discrimination. OBJECTIVES: The aim of the present study is to examine whether the spatial ability measured by the right-left discrimination task can be affected by heroin abuse and whether such drug effect, if it exists, is gender related. METHODS: A paper-and-pen test was used. The test consists of line drawings of a person with no arm, one arm, or both arms crossing the vertical body axis of the figure. The line drawings are viewed from the back, from the front, or randomly alternating between the back and front drawings. The subjects' task is to mark which is the right or left hand in the figure as fast as possible. RESULTS: A main finding in this study was that the ability to discriminate between left and right in visual space was impaired in heroin-dependent patients. Especially, heroin-dependent females performed poorer than control females in all conditions but heroin-dependent males only performed poorly in part of conditions. CONCLUSIONS: Recent heroin abuse impairs the ability of right-left discrimination and such impairment is gender related: heroin-dependent females demonstrated greater performance deficits than males.

Adult↗
PubMed2005

EEG activities in the orbitofrontal cortex and dorsolateral prefrontal cortex during the development of morphine dependence, tolerance and withdrawal in rhesus monkeys.

Investigating the activities of the prefrontal cortex (PFC) in the process of addiction is valuable for understanding the neural mechanism underlying the impairments of the PFC after drug abuse. However, limited data are obtained from primate animals and few studies analyze Electroencephalogram (EEG) in the gamma band, which plays an important role in cognitive functions. In addition, it is yet unclear whether drug abuse affects the orbitofrontal cortex (OFC) and dorsolateral PFC (DLPFC)--the two most important subregions of the PFC--in similar ways or not. The aim of this study is to address these issues. We recorded EEG in the OFC and DLPFC in three rhesus monkeys. All animals received a course of saline (NaCl 0.9%, 2 ml) injection (5 days) followed by 10 days of morphine injection (every 12 h), and then a further series of saline injection (7 days). A main finding in the present study was that morphine decreased EEG power in all frequency bands in a short period after injection in both the OFC and DLPFC in monkeys. And gamma power decreased not just in a short period after morphine injection but lasted to 12 h after injection. Moreover, we found that although the changes in EEG activities in the OFC and DLPFC at 30-35 min after injection were similar, the DLPFC was more sensitive to the effect of morphine than the OFC.

Analysis of Variance↗