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Biomedical subjects

Xin Liu

Publications and source records attributed to Xin Liu.

At least 181 records · Page 10Linked to original sources
PubMed2003

Effect of enterokinetic prucalopride on intestinal motility in fast rats.

AIM: To evaluate the effects of prucalopride on intestinal prokinetic activity in fast rats and to provide experimental basis for clinical treatment of gastrointestinal motility diseases. METHODS: Gastrointestinal propulsion rate was measured by the migration rate of activated charcoal, which reflexes gastrointestinal motility function. 120 Spraque-Dawley rats were randomly divided into four groups and received an intravenous injection of physiological saline (served as control), prucalopride 1 mg/kg, prucalopride 2 mg/kg and cisapride 1 mg/kg, respectively. The gastrointestinal propulsion rate was measured 1, 2 or 4 hours after intravenous injection of the drugs. RESULTS: Significant accelerations of gastrointestinal propulsion rate in prucalopride 1 mg/kg and 2 mg/kg groups were found compared with control group at 2 and 4 hours(83.2 %+/-5.5 %, 81.7 %+/-8.5 % vs 70.5 %+/-9.2 %, P<0.01; 91.2 %+/-2.2 %, 91.3 %+/-3.9 % vs 86.8 %+/-2.6 %, P<0.01). The gastrointestinal propulsion rates at 1, 2 or 4 hours were faster in prucalopride 1 mg/kg and 2 mg/kg groups than in cisapride group (84.0 %+/-11.7 %, 77.1 %+/-11.9 % vs 66.3 %+/-13.6 %, P<0.01, P<0.05; 83.2 %+/-5.5 %, 81.7 %+/- 8.5 % vs 75.4 %+/-5.9 %, P<0.01, P<0.05; 91.2 %+/-2.2 %, 91.3 %+/-3.9 % vs 88.6 %+/-3.5 %,P<0.05, P<0.05). No difference of gastrointestinal propulsion rate was found between prucalopride 1 mg/kg group and prucalopride 2 mg/kg group (P>0.05). CONCLUSION: Prucalopride accelerates intestinal motility in fast rats, and has no dose dependent effect.

Animals↗
PubMed2003

[Study on sperm quality of the soldiers influenced by reinforced training].

OBJECTIVES: To investigate the correlation between abnormal sperm parameters and reproductive hormones and reinforced training. METHODS: Epidemic investigation were done between two different groups by determining endocrine hormone and standard clinical sperm analysis. RESULTS: Comparison between reinforced training group and non-training group showed decreased sperm velocity but no change on sperm moving form, increased teratism sperm percentage but no change on sperm number, decreased plasma testosterone but no change on LH. CONCLUSIONS: Reinforced training has correlation with weak part of sperm parameter analysis and reproductive hormones.

Humans↗
PubMed2003

[Establishment of a human nasopharyngeal carcinoma drug-resistant cell line CNE2/DDP and screening of drug-resistant genes].

BACKGROUND & OBJECTIVE: Chemotherapy constitutes one of the chief supplementary methods in the treatment of nasopharyngeal carcinoma (NPC). However, the appearance of drug resistance often causes failure of chemotherapy. For overcoming drug resistance, it is of great importance to screen drug-resistant associated genes so as to identify potential molecular targets. This study was designed to establish a drug-resistant cell line from a human nasopharyngeal carcinoma cell line CNE2, and to screen human nasopharyngeal carcinoma drug-resistant genes by a new strategy based on improved subtractive hybridization. METHODS: The drug-resistant cell line was established by a program of treating the human nasopharyngeal carcinoma cells CNE2 in the medium with repeated sharp high and then low but gradually increasing concentration of cisplatin. Drug sensitivity was measured by MTT assay. Fluorescence activated cell analysis(FACS) was employed for determining the concentration of fluorescence dye rhodamine 123 within the cells. Cell growth curve, doubling time, and cell morphology were measured and observed. The drug-resistant genes were screened by a new strategy of PCR-based subtractive hybridization. Sequencing and blast analysis were performed after the differentially expressed genes had been verified by reverse dot blotting. The result was further confirmed by RT-PCR. RESULTS: The resistance indexes of CNE2/DDP to cisplatin (DDP), 5-fluorouracil (5-FU), and vincristine (VCR) were 27.9, 227.9, and 55.5, respectively, indicating its multi-drug resistant property. FACS analysis showed that the concentration of rhodamine 123 was much lower in CNE2/DDP cells than in CNE2 cells (12.98 vs. 243.62). The CNE2/DDP cells appeared smaller, more regularly round, and longer doubling time (26 hours vs. 19 hours) than CNE2 cells. Six differentially expressed sequences were discovered using improved subtractive hybridization; all of them were found to be homologous to known genes after sequencing analysis. Three of them were highly expressed in CNE2/DDP cells. Among them, one sequence, which encodes a 79 amino acid protein,known as DC13 protein (DC13), was a function unknown gene which has certain relationship with malignancy. The other two sequences were ubiquitin C gene and NADH dehydrogenase subunit 2 (ND2) gene, respectively. The other three of the six sequences, whose expression were inhibited in CNE2/DDP cells, were cytochrome C oxidase subunit I(COX1), ribosomal protein L27(RPL27),and ribosomal protein S27 (RPS27) genes, respectively. CONCLUSION: A drug- resistant cell line CNE2/DDP, which showed a typical resistant phenotype to anti-cancer drugs was established. The PCR-based improved subtractive hybridization is an effective approach to identify differentially expressed genes. Many genes, both known and unknown, might contribute to the existence of drug-resistant phenotype, through increasing or decreasing their expression.

Antineoplastic Agents↗
PubMed2003

[Evaluation of radiation damage to the sperm DNA of radar operators].

OBJECTIVE: To evaluate the inflicted by radar electromagnetic radiation to the sperm DNA of radar operators. METHODS: Sperm concentration, viability, motility, sperm abnormality were determined by routine sperm analysis and sperm chromatin structure assay (SCSA) in the highly exposed group(n = 88), lowly exposed group(n = 143) and control group(n = 39). RESULTS: Sperm motility, viability of the highly exposed group reduced compared with that of the lowly exposed group and control group, while sperm abnormality increased. The COMP alpha reduction of the highly exposed group indicated that the highly exposed group had a medium fertility potential. The multifactor variable analysis showed that daily working time was a dangerous factor in sperm abnormality and abstinence time was a dangerous factor in the parameter of SCSA. CONCLUSIONS: Radar radiation inflicts damage to male reproduction system and it is important to take protective measures.

Adolescent↗
PubMed2003

[Construction and important factors analysis of natural life table of diamonthback moth, Plutella xylostella under pesticides treatment].

The natural life tables of diamonthback moth (DBM), Plutella xylostella under pesticides treatment were constructed, and the construction method of item "pesticide" was particularly discussed. The life tables indicated that the indices of population trend (I) under the treatment with 80% Dichlorvos EC 1000x and the contrast were 0.7796 and 1.4804, respectively, showing that Dichlorvos had some control on DBM. But, Dichlorvos had some effects on natural enemies of DBM. The decrease of parasitism rate at pupa stage was most obvious, which indicated that Dichlorvos had some effects of killing and wounding on the natural enemies of DBM.

Animals↗
PubMed2002

[Regulation of lipopolysaccharide-induced inducible nitric oxide synthase gene expression by protein kinase C].

OBJECTIVE: To explore the molecular mechanism of inducible nitric oxide synthase (iNOS) gene expression induced by lipopolysaccharide (LPS) in monocytes or macrophages. METHODS: Luciferase report gene vector pGL2iNOSLuc driven by murine iNOS promoter region was constructed using gene recombination technique. RAW264.7 cells were cultured and transfected with luciferase report gene vector pGL2iNOSLuc. Twenty four hours later, PKC inhibitor H-7, calcium channel blocker verapamil, was added into the culture. LPS or PKC activator PMA was added 2 hours later to stimulate the cells. The activity of beta-galactosidase and luciferase was examined and the relative luciferase activity, representing the iNOS transactivity, was calculated. Modified Griess method was used to measure the concentration of NO(2)(-)/NO(3)(-) in the culture so as to evaluate the effect of PKC inhibitor on NO production induced by LPS. RT-PCR was used to study the effect of LPS on iNOS gene expression in RAW264.7 cells. RESULTS: Thirty minutes after stimulation of RAW264.7 cells by LPS, the activity of PKC in cytomembrane increased and the activity of PKC in cytoplasm decreased significantly in comparison with the baseline levels (P < 0.01). The NO concentration was 30.1 micro mol/L +/- 5.4 micro mol/L 12 hours after the stimulation of LPS on RAW264.7 cells, and was much more higher 24 and 48 hours after, all significantly higher than before (all P < 0.01). The NO concentration in the supernatant with H-7 at any time point was significantly lower than those in corresponding samples without H-7 (all P < 0.01). After stimulation of LPS and PMA, the relative luciferase activity was 25.3 +/- 4.6, significantly higher than the baseline level (P < 0.01). H-7 and verapamil significantly inhibited the LPS-induced iNOS transactivity (both P < 0.01). iNOS mRNA expression was increased greatly, and H-7 significantly inhibited this expression 12, 24, and 48 hours after LPS stimulation. CONCLUSION: In RAW264.7 cells, LPS stimulation increases intracellular calcium and activates PKC, thus inducing iNOS gene expression that contributes to the production of NO, which is an important signaling mechanism of NO production in septic shock.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2002

Antitumor activity of the sporoderm-broken germinating spores of Ganoderma lucidum.

The inhibitory effects of the dormant spores, the germinating spores, the sporoderm-broken germinating spores (SBGS), and the lipids extracted from the germinating spores of Ganoderma lucidum on the growth of mouse hepatoma, sarcoma S-180, and reticulocyte sarcoma L-II cells were investigated, respectively. The dormant spores could be activated by germination, and thus the bioactivities of the spores might be enhanced. The sporoderm-broken spores could show much higher bioactivities than the whole spores. Both the lipids extracted from the germinating spores and the SBGS of G. lucidum had remarkable antitumor effects in a dose-dependent manner, and could significantly inhibit three tumors with an inhibition of 80-90%.

Administration, Oral↗
PubMed2002

Simplified amino acid alphabets based on deviation of conditional probability from random background.

The primitive data for deducing the Miyazawa-Jernigan contact energy or blocks substitution matrix (BLOSUM) consists of pair frequency counts. Each amino acid corresponds to a conditional probability distribution. Based on the deviation of such a conditional probability from random background, a scheme for the reduction of the amino acid alphabet is proposed. It is observed that an evident discrepancy exists between the reduced alphabets obtained from the raw data of the Miyazawa-Jernigan's and BLOSUM's residue pair counts. Taking a homologous sequence database SCOP40 as a test set, we detect homology with the obtained coarse-grained substitution matrices. It is verified that the reduced alphabets obtained well preserve information contained in the original 20-letter alphabet.

Algorithms↗
PubMed2002

Purple acid phosphatases of Arabidopsis thaliana. Comparative analysis and differential regulation by phosphate deprivation.

Purple acid phosphatases (PAPs) are members of the metallo-phosphoesterase family. They are characterized by the presence of seven conserved amino acid residues involved in coordinating the dimetal nuclear center in their reactive site. We compared the 29 PAPs predicted for Arabidopsis thaliana in their varieties of potential metal-ligating residues. Although 24 members possessed sets of metal-ligating residues typical of known PAPs, 1 member lacked four of the seven residues. For the remaining four members, potential metal-ligating residues were generally more similar to those in metal-dependent exonucleases and related proteins. Evidence was obtained for the expression of the majority of the 29 PAPs. To facilitate future investigations, a scheme for naming Arabidopsis PAPs and a system for classifying the 29 PAPs are proposed. The cDNA sequences and the responses to phosphate deprivation of seven Arabidopsis PAPs (AtPAP7-AtPAP13) were characterized. For some AtPAPs analyzed, there were fully processed transcripts as well as splice variants. The splice variants of AtPAP10 were found to associate with polyribosomes and may be translated into a NH(2)-terminal truncated protein. Phylogenetic investigations showed that AtPAPs 7 and 8, together with similar enzymes from other plant species, formed the low molecular weight plant PAP group. Members of this group were more closely related to PAPs from mammalian cells. AtPAPs 9-13, together with kidney bean PAP, formed the high molecular weight PAP group. In phosphate deprivation experiments, gene transcription of AtPAP11 and AtPAP12 was induced and increased, respectively, whereas that of the remaining five AtPAPs was not affected by phosphate deprivation. The present work demonstrates that structure variation and expression regulation of plant PAPs are more complex than previously described and provides a framework for comprehensive molecular genetic and biochemical studies of all Arabidopsis PAPs in the future.

Acid Phosphatase↗
PubMed2002

Iridoids from the rhizomes and roots of Valeriana jatamansi.

Five new iridoids, 1-homoacevaltrate (1), 1-homoisoacevaltrate (2), 11-homohydroxyldihydrovaltrate (3), 10-acetoxy-1-homovaltrate hydrin (4), and 10-acetoxy-1-acevaltrate hydrin (5), along with 10 known analogues, were isolated from the rhizomes and roots of Valeriana jatamansi. Structural elucidation was based on spectroscopic data interpretation.

China↗
PubMed2002

Activity of polymerase proteins of vaccine and wild-type measles virus strains in a minigenome replication assay.

The relative activities of five measles virus (MV) polymerase (L) proteins were compared in an intracellular, plasmid-based replication assay. When coexpressed with N and P proteins from an attenuated strain, L proteins from two attenuated viruses directed the production of up to eight times more reporter protein from an MV minigenome than the three wild-type L proteins. Northern blot analysis demonstrated that the differences in reporter protein production correlated with mRNA transcription levels. Increased activity of polymerases from attenuated viruses equally affected mRNA transcription and minigenome replication. The higher level of transcription may be a consequence of increased template availability or may be an independent effect of the elevated activity of the attenuated polymerases. Coexpression of wild-type L proteins with homologous N and P proteins did not affect the activity of the wild-type polymerases, indicating that the differential activity was a function of the L proteins alone. Use of a minigenome that incorporated two nucleotide changes found in the genomic leader of the three wild-type viruses did not raise the activity of the wild-type L proteins. These data demonstrate that increased polymerase activity differentiates attenuated from wild-type viruses and suggest that functions involved in RNA synthesis contribute to the attenuated phenotype of MV vaccine strains.

Amino Acid Sequence↗
PubMed2002

Essential role of AKT-1/protein kinase B alpha in PTEN-controlled tumorigenesis.

PTEN is mutated at high frequency in many primary human cancers and several familial cancer predisposition disorders. Activation of AKT is a common event in tumors in which the PTEN gene has been inactivated. We previously showed that deletion of the murine Pten gene in embryonic stem (ES) cells led to increased phosphatidylinositol triphosphate (PIP(3)) accumulation, enhanced entry into S phase, and better cell survival. Since PIP(3) controls multiple signaling molecules, it was not clear to what degree the observed phenotypes were due to deregulated AKT activity. In this study, we mutated Akt-1 in Pten(-/-) ES cells to directly assess the role of AKT-1 in PTEN-controlled cellular processes, such as cell proliferation, cell survival, and tumorigenesis in nude mice. We showed that AKT-1 is one of the major downstream effectors of PTEN in ES cells and that activation of AKT-1 is required for both the cell survival and cell proliferation phenotypes observed in Pten(-/-) ES cells. Deletion of Akt-1 partially reverses the aggressive growth of Pten(-/-) ES cells in vivo, suggesting that AKT-1 plays an essential role in PTEN-controlled tumorigenesis.

Animals↗
PubMed2002

Conditional loss of PTEN leads to precocious development and neoplasia in the mammary gland.

PTEN tumor suppressor is frequently mutated in human cancers, including breast cancers. Female patients with inherited PTEN mutations suffer from virginal hypertrophy of the breast with high risk of malignant transformation. However, the exact mechanisms of PTEN in controlling mammary gland development and tumorigenesis are unclear. In this study, we generated mice with a mammary-specific deletion of the Pten gene. Mutant mammary tissue displayed precocious lobulo-alveolar development, excessive ductal branching, delayed involution and severely reduced apoptosis. Pten null mammary epithelial cells were disregulated and hyperproliferative. Mutant females developed mammary tumors early in life. Similar phenotypes were observed in Pten-null mammary epithelia that had been transplanted into wild-type stroma, suggesting that PTEN plays an essential and cell-autonomous role in controlling the proliferation, differentiation and apoptosis of mammary epithelial cells.

Animals↗
PubMed2002

[The effect of dipyridamole and adenosine on pulmonary fibrosis in mice].

OBJECTIVE: To evaluate the effect of dipyridamole (DPM) and adenosine (ADO) on interstitial pulmonary fibrosis in mice. METHODS: 100 mice injected with Bleomycin (BLM, 8.5 mg/kg) by intratracheal were divided into a control group and groups treated by DPM, ADO, DPM and theophyline (TH). Pulmonary pathology from day 4 to day 30 observations was studied by light and electron microscope. RESULTS: Alveolar epithelial cell necrosis, lung tissue lesions by hypoxia and interstitial fibrosis were found in the BLM group after day 10. The necrotic epithelial cell, fibroblast proliferation, and the hypoxia induced tissue damage were less prominent, and the number and phagocytic function of macrophages were increased in the DPM and ADO treated groups. In the TH treated group, necrotic epithelial cells increased, the lung tissue was ischemic, and the differentiation of monocytes in pulmonary interstitial was slower. CONCLUSION: DPM and ADO can inhibit fibroblast proliferation by improving microcirculation and promoting macrophage development and alveolar space reconstruction.

Adenosine↗
PubMed2002

[Treatment of two case childhood acute lymphoblastic leukemia by HLA-mismatched unrelated umbilical cord blood transplantation].

OBJECTIVE: To explore the hematopoietic and immunologic reconstitution and transplantation-related complications of HLA one locus mismatched unrelated umbilical cord blood transplantation for the treatment of hematological malignancies. METHODS: Two children with acute lymphoblastic leukemia received HLA-mismatched unrelated umbilical cord blood transplantation. The conditioning regimens were BU-CTX (case 1) and BU-CTX plus BCNU (case 2). GVHD prophylaxis regimen consisted of cyclosporine (CsA) and mycophenolate mofetil (MMF). The patients received 14.6 x 10(7) nucleated cells/kg with 7.24 x 10(5) CD(34)(+) cells/kg and 16.24 x 10(7) nucleated cells/kg with 21.11 x 10(5) CD(34)(+) cells/kg, respectively. RESULTS: The two recipients, ANC > 0.5 x 10(9)/L occurred at day 27 and day 17, BPC > 50 x 10(9)/L at day 53 and day 46, the peripheral blood counts normalization at day 60 and day 52, the immune function normalization at day 134 and day 122 and the DNA fingerprinting showing engraftment at day 19 and day 17, respectively. The donor-recipient pair of case 1 was male to female, and the chromosome karyotype of recipients bone marrow and peripheral blood cells showed 100%, 46, XY cells at day 49. Grade II acute graft versus host disease (aGVHD) occurred at day 26 (case 1) and day 21 (case 2). The two recipients have survived for 353 days and 256 days. CONCLUSION: The hematopoietic and immunologic reconstitution in umbilical cord blood transplantation were earlier and more durable. The transplantation-related complications were less and aGVHD were milder.

Child, Preschool↗
PubMed2002

[Epidemiological study on taeniasis and cysticercosis in Shandong Province].

OBJECTIVE: To investigate current epidemiological status of Taenia solium infection and cysticercosis in Shandong Province. METHODS: By house to house interview in the field, fecal examination and serological tests, the prevalence data of taeniasis and cysticercosis in human and pig population, and epidemiological factors in relation to the diseases were carried out. RESULTS: The prevalence of Taenia infection and cysticercosis in human population were 0.048% and 0.057% respectively. The sero-positive rate of the specific IgG4 of anti-Cysticercus was 1.91%. The prevalence differed among occupations and from region to region, but there was no significant difference between men and women, city and suburb. Unhealthy eating and unhygienic habits commonly practised among residents, 92.3% of the families have "latrines connected to pigsties". The surrounding sanitation and the disposal of fecal material were poor. The detection rate of porcine cysticercosis was 0.06%, and the positive rate of anti-Cysticercus antibody in pigs was 1.99%. CONCLUSION: The prevalence of taeniasis and cysticercosis is decreasing. However, the endemic area is expanding and the epidemiological factors are still existing. Continued effort is therefore needed for sustain the control programme.

Adolescent↗
PubMed2002

[Study on forensic expertise of medical tangle].

OBJECTIVE: To study the characteristics of forensic expertise of medicial tangle, and explore the emphases and difficuties of forensic expertise. METHODS: The medical defect was classflied into the negliget defect, the technical defect, the administive defect, the learned defect and other defect. The 36 cases were analised according to the above-mentioned way. RESULTS: 86.11% of the 36 cases has the technical defect, 25% has the negliget defect and the administive defect. There were significant different between the our expertise opinion and Medical Tangle Expertise Committee's conclusion (P < 0.05, P < 0.01). CONCLUSION: The forensic expertise of medical tangle play the positive role in deal with the medical tangle cases, but there are many problems to further explore in forensic expertise.

Adolescent↗