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Biomedical subjects

Bo Liu

Publications and source records attributed to Bo Liu.

At least 145 records · Page 8Linked to original sources
PubMed2004

Analysis of the coupling of G12/13 to G protein-coupled receptors using a luciferase reporter assay.

G protein-coupled receptors (GPCRs) transduce signals from cell surface to intracellular effectors through various G proteins. In this chapter, a luciferase reporter gene assay system is described for the study of the coupling of GPCRs to G alpha 12/13. This assay system, in which ligand-stimulated production of the reporter luciferase under the control of a modified serum-responsive element (SRE) in a cell line derived from mice lacking G alpha q/11 that are transfected with a GPCR of interest, allows for easy, fast, and valid determination of the coupling of the GPCR to G alpha 12/13.

Animals↗
PubMed2004

Analysis of G protein-mediated activation of phospholipase C in cultured cells.

Inositide-specific phospholipase C (PLC) beta can be activated by the Gq family of G alpha subunits and by the G beta gamma subunits of heterotrimeric G proteins. PLC catalyzes the hydrolysis of phosphotidylinositol 4,5-bisphosphates (PIP2) to inositol trisphosphate (IP3) and diacylglycerol (DAG). This chapter describes a cell-based assay system to determine the activity of PLC by monitoring the levels of IPs in cultured cells. This assay system can be used to examine the activation of G protein-coupled receptors (GPCRs), coupling of GPCRs to G proteins, and the interactions of G proteins to PLC beta.

Animals↗
PubMed2004

Aberration of X chromosome in liver neoplasm detected by fluorescence in situ hybridization.

BACKGROUND: A diverse range of cytogenetic alterations of autosomal chromosomes has been reported to date. However, few studies have addressed the abnormalities of X chromosome in hepatocellular carcinoma (HCC) except sporadic reports on the deletion of band F1 in X chromosome, and the clonal analysis of methylation pattern of the X chromosome-linked human androgen receptor gene. Identification of specific X chromosome alterations during the course of neoplastic development would be essential to defining the genetic basis of HCC. Therefore, we studied the regularity of aberration of X chromosome in liver cancer. METHODS: Hepatocarcinoma cellular lines and tumor tissues were detected respectively through DNA probes of X chromosome after fluorescence in situ hybridization (FISH). RESULTS: Increased copies of X chromosome were observed in all samples, and four signals of hybridization were of the major type. CONCLUSIONS: Increased copy number of X chromosome frequently occur in liver cancer. The relationship between copy number of X chromosome and liver cancer genesis needs further investigation. This study is the first of its kind determining the copy number of X chromosome in liver cancer by using FISH.

Adult↗
PubMed2004

[Biological characteristics of female rabbit clitoral smooth muscle cell culture in vitro].

OBJECTIVE: To investigate the method of culturing rabbit clitoral smooth muscle cells(SMC) in vitro and their biological characteristics. METHODS: Rabbit clitoral SMCs were cultured in vitro by enzymatically dispersed method, and morphological observation, cell counting and immunohistochemical staining were employed to study their biological characteristics. RESULTS: Rabbit clitoral SMCs were spindle-shaped and parallelled along their longitudinal axis, and the attachment and proliferation in vitro were rapid. CONCLUSION: Rabbit clitoral SMCs cultured in vitro can grow and maintain their steady characteristics when provided with appropriate culture condition. Clitoral SMCs cultured in vitro can serve as a cell material for researches of clitoris.

Animals↗
PubMed2004

[Multi-channel cochlear implants in patients with Mondini malformation].

OBJECTIVE: To describe clinical experiences with multi-channel cochlear implantation in patients with Mondini malformation. METHODS: Among 300 patients who received multi-channel cochlear implants from 1996 to 2002 in Beijing Tongren Hospital, 15 patients were diagnosed with Mondini malformation. A retrospective analysis was performed dealing with the surgical techniques, mapping and rehabilitations characteristics after surgery. 15 patients with normal cochlear structure are consider as control group. RESULTS: Gusher is found more common than the normal cochlear implantation, most of them are serious. The electrodes are inserted in the "cochleostomy" in full length of 13 Patients, 2 pairs of electrodes remains outside of "cochleostomy" in 2 patients. No serious complications occurred after implantation. All patients have auditory sensations. The impedance of the electrodes, the T level, C level and the hearing threshold are similar with the normal cochlear implantation group. The results have no significant difference in compare with normal cochlear group(P > 0.05). CONCLUSION: Multi-channel cochlear implantation could be performed safely in patients with Mondini malformation. The primary outcome for patients with Mondini malformation are similar to those with normal cochlear structure following the multi-channel cochlear implantation.

Adolescent↗
PubMed2004

[The psychophysical tests in different age of patients with cochlear implants].

OBJECTIVE: The aim of this research is to analyse and compare the psychophysical tests in different age of patients with a cochlear implant. METHOD: One hundred and seventy patients with Nucleus CI24M cochlear implant system participated in this study. The patients were divided into four groups according to their age. They were group A (<3 year), B(3-<6 year) C(6-12 year) and D(>12 year). The psychophysical tests included T and C-Level evaluation. RESULT: C-Levels of each electrode (except electrode No. 20) were significantly different between group A and D at the time of one month after switch-on (P<0.01, P<0.05 for the No. 2, 18, 19, 21, 22 electrode). The normalized differences between used C-Levels and C-Levels for group D were significantly higher than the other three groups at the switch-on session (P<0.01, P<0.05 between group D and C). The normalized differences between used C-Levels and C-Levels were significantly different for the group A and D at one week after first programming session (P<0.05). CONCLUSION: T and C-Level for different age groups were different. The normalized differences between used C-Levels and C-Levels were significantly different among the four groups in the few weeks after switch-on.

Adolescent↗
PubMed2004

[Analysis of genetic relationship among Chinese native chicken breeds using microsatellites marker].

The allele frequencies, heterozygosity (H), mean heterozygosity, polymorphism information content (PIC) and genetic relationships were studied in Luyuan chicken, Gushi chicken, Tibetan chicken, Baier chicken, Xianju chicken, Chahua chicken, Dagu chicken,Beijing Fatty chicken, Langshan chicken, Henan Game chicken,Taihe Silkies chicken and Xiaoshan chicken using seven microsatellite DNA markers. The results showed that there were differences among allele fequencies of seven microsatellite loci in 12 Chinese native chicken breeds. Among the 12 Chinese native chicken breeds, mean heterozygosity of Luyuan chicken was the highest (0.5929), and that of Chahua chicken was the lowest (0.3514). There were similar results in PIC. By fuzzy cluster analysis was found that the genetic relationship between Taihe Silkies chicken and Henan Game chicken was the nearest, and that between Gushi chicken and the other chicken breeds was the most distant. The 12 Chinese native chicken breeds were divided into three group by fuzzy cluster analysis. The first group included Taihe Silkies chicken, Henan Game chicken, Langshan chicken, Xiaoshan chicken, Dagu chicken, Beijing Fatty chicken and Luyuan chicken, the second group included Chahua chicken, Tibetan chicken, Xianju chicken and Baier chicken, and the third group included Gushi chicken.

Animals↗
PubMed2004

Isolation and characterization of deodorizing bacteria for organic sulfide malodor.

Strain JII screened out from different odor origins can efficiently degrade methyl mercaptan and ethanethiol whereas has no ability to remove dimethyl sulfide. The results indicated that the strain JII breaks only the C-SH bond. The optimum temperature and pH of JII are 20-30 degrees C and 6.0-8.3 respectively. A systematic identification method-16S rDNA gene sequence comparison, for deodorizing bacteria was carried out. The 16S rDNA gene sequence analysis of strain JII showed the highest level of 97% homology to Rape rhizosphere.

Bacteria↗
PubMed2004

[Research on the basic properties of spontaneous otoacoustic emissions].

OBJECTIVE: To record and analyze the basic properties of spontaneous otoacoustic emission (SOAE) and to study the application of SOAE. METHOD: Forty cases (80 ears) with normally hearing subjects and 96 cases with abnormal hearing subjects were tested by ILO92 Otodynamics Analyzer. RESULT: (1) SOAE frequencies ranged from about 0.5 kHz to 6 kHz, it's amplitudes distributed between -28 and 6 dB SPL; (2) 49% had SOAE and there were no significant difference in sexuality in normal hearing subjects. During long duration observation, frequency of SOAE was no change; (3) Amplitude of SOAE could be suppressed by contralateral white noise; (4) There were some difference in different hearing loss group for SOAE. CONCLUSION: The presence of SOAE indicated that there is a better function for out hair cells of cochlear.

Adolescent↗
PubMed2004

[Effect of captopril on expression of PTEN in aorta of aortic-induced hypertensive rats].

This study inquired about the role of tumor suppressor PTEN in the arterial remodeling of Ang II induced hypertension. The expression of PTEN of aorta was examined in the aortic-constricted hypertensive rats (hypertension group), in the aortic-constricted hypertensive rats treated with captopril(hypertension and captopril group), and in the rats having undergone sham operation (control group). At day 28 after surgery, the aortas were collected from the groups. The expression of PTEN mRNA was detected by RT-PCR. The expression and location of PTEN protein were determined by immunohistochemistry. The results showed that the expression of PTEN in aorta of the hypertension group was significantly lower than that of the hypertension and captopril group, and similarly lower than that of the control group. The intensity of PTEN-positive immunohistochemical production in aorta of the hypertension group was weaker than that of the hypertension and captopril group, and likewise, it was weaker than the control. PTEN-positive immunohistochemical production was located in VSMC of aorta. The findings indicated that the expression of PTEN is reduced in hypertensive aorta, that the reduced PTEN experession can be reversed by captopril treatment, that AngII and the increased mechanical strain may participate in regulating expression of PTEN, and that PTEN may play a role in the arterial remodeling induced by hypertension.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2004

[Cochlear implantation in patients with inner ear malformations].

OBJECTIVE: To describe clinical experiences with multi-channel cochlear implantation in patients with bilateral inner ear malformations. METHODS: Among 410 patients who received multi-channel cochlear implantations from 1996 to 2004 in Beijing Tongren Hospital, 82 patients were diagnosed with inner ear malformations and implanted. A retrospective analysis was performed about the surgical characteristics and mapping characteristics after implantation. RESULTS: (1) All patients had auditory sensations. (2) Gusher was more common than the normal cochlear implantation. (3) The electrodes were inserted in the "cochleostomy" in full length of 80 Patients, but 2 pairs of electrodes remained outside of "cochleostomy" in 2 patients. (4) No serious complications occurred after implantation. (5) The impedance of the electrodes, the T level and C level were similar with the normal cochlear implantation. The results had no significant difference in compare with normal cochlear group (P > 0. 05). (6) The abilities of speech discrimination and spoken language were improved through rehabilitation. CONCLUSIONS: The cochlear implantation can be performed safely in inner ear malformations. The outcome of hearing rehabilitation for patients with inner ear malformations are similar to those children with normal cochlear structure followed the multi-channel cochlear implantation.

Adolescent↗
PubMed2004

[Quality evaluation of Alisma orientalis from different habitats].

OBJECTIVE: To study the seed quality of Alisma orientalis (Sam.) Juzep. METHOD: Collecting seeds from different habitats and studying the thousand-grain weight, moisture content, purity and germination percentage. RESULT: The seeds reaped in summer friom Pengshan, Sichuan province are better than those from other habitats. Its thousand-grain weight is 0.4682 g, moisture content is 12.48%, purity of seeds is 89.18% and germination percentage is above 95%. CONCLUSION: The cause of qualitative differences in seeds of Alisma orientalis from different habitats were analysed in this paper.

Alisma↗
PubMed2004

[Splenectomy combined with endoscopic variceal ligation in treating portal hypertension].

OBJECTIVE: To investigate the therapeutic effect of endoscopic variceal ligation (EVL) combined with splenectomy on patients with portal hypertension. METHODS: The eliminating rate of varicose veins and recurrent bleeding rate were evaluated. Fifty-one paitents with cirrhosis of liver and portal hypertension were randomly divided into 2 groups. We treated 25 portal hypertensive patients using splenectomoy plus EVL. The therapeutic effect of pericardial devascularization in 26 patients with upper gastrointestinal bleeding due to portal hypertension served as the control. RESULTS: All patients were followed up for 12 months. There was no death due to the operation. All patients in the study group had no upper gastrointestinal rebleeding during the 12-month follow-up. The rebleeding rate in the control group was 11.5% (3/26). The varicose venis eliminating rate was 96% (24/25) in the study group and 50% (13/26) in the control group (P < 0.01). It showed no effect on portal hypertensive gastropathy in the study group, and pericardial devascularization procedure exacerbated the portal hypertensive gastropathy. The thrombosis rate in the portal vein after the operation was 8% (2/25) in the study group and 34.6% (9/26) in the control group (P < 0.05). CONCLUSION: EVL combined with splenectomy has less trauma, fewer postoperative complications and high eradication of esophageal varices. It can be used safely in treating portal hypertension.

Esophageal and Gastric Varices↗
PubMed2003

Eradication of pathogenic beta-catenin by Skp1/Cullin/F box ubiquitination machinery.

The use of Skp1/Cull 1/F box (SCF) ubiquitin-conjugation machinery as a potential knockout tool offers a means of eradicating disease-causing proteins. Here a chimeric F box protein (CFP) was engineered to achieve selective eradication of pathogenic beta-catenin in colorectal cancer. We show that CFP specifically searches for and subsequently links the abnormal beta-catenin to the cellular SCF ubiquitination complex. Introduction of the CFP to colorectal cancer cells induced targeted ubiquitination and proteolytic degradation of nuclear and cytoplasmic free beta-catenin while preserving its normal cellular adhesion counterpart. Elimination of pathogenic beta-catenin suppressed constitutive Wingless/Wnt signaling and inhibited in vitro and in vivo tumor cell growth. This study demonstrates a practical utility of a SCF-based knockout system as a tool in targeting an abnormal protein that affects growth and transformation.

Cell Division↗
PubMed2003

Structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3C protease inhibitors. 8. Pharmacological optimization of orally bioavailable 2-pyridone-containing peptidomimetics.

The optimization of the pharmacokinetic performance of various 2-pyridone-containing human rhinovirus (HRV) 3C protease (3CP) inhibitors following oral administration to either beagle dogs or CM-monkeys is described. The molecules described in this work are composed of a 2-pyridone-containing peptidomimetic binding determinant and an alpha,beta-unsaturated ester Michael acceptor moiety which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. Modification of the ester contained within these compounds is detailed along with alteration of the P(2) substituent present in the peptidomimetic portion of the inhibitors. The pharmacokinetics of several inhibitors in both dogs and monkeys are described (7 h plasma concentrations after oral administration) along with their human plasma stabilities, stabilities in incubations with human, dog, and monkey microsomes and hepatocytes, Caco-2 permeabilities, and aqueous solubilities. Compounds containing an alpha,beta-unsaturated ethyl ester fragment and either an ethyl or propargyl P(2) moiety displayed the most promising combination of 3C enzyme inhibition (k(obs)/[I] 170 000-223 000 M(-1) s(-1)), antiviral activity (EC(50) = 0.047-0.058 microM, mean vs seven HRV serotypes), and pharmacokinetics following oral administration (7 h dog plasma levels = 0.248-0.682 microM; 7 h CM-monkey plasma levels = 0.057-0.896 microM).

3C Viral Proteases↗
PubMed2003

Coulomb explosion upon electron attachment to a four-coordinate monoanionic metal complex.

Electron capture to monoanionic metal complexes in high-energy collisions with sodium vapor is shown to occur with the formation of dianions. In this way, we prepared the small dianions Cr(SCN)42-, Fe(CN)42-, Pt(NO2)22-, and Pt(C2O4)22- in the gas phase. The Cr(SCN)42- dianion Coulomb explodes into Cr(SCN)3- and SCN- with a release of kinetic energy (3.2 +/- 0.4 eV) into translational energy of the fragments. The scheme provides a way to study charge dissociation reactions of molecular dianions that are too short-lived to survive extraction from the ion source.

Journal Article↗
PubMed2003

Directional sensing requires G beta gamma-mediated PAK1 and PIX alpha-dependent activation of Cdc42.

Efficient chemotaxis requires directional sensing and cell polarization. We describe a signaling mechanism involving G beta gamma, PAK-associated guanine nucleotide exchange factor (PIX alpha), Cdc42, and p21-activated kinase (PAK) 1. This pathway is utilized by chemoattractants to regulate directional sensing and directional migration of myeloid cells. Our results suggest that G beta gamma binds PAK1 and, via PAK-associated PIX alpha, activates Cdc42, which in turn activates PAK1. Thus, in this pathway, PAK1 is not only an effector for Cdc42, but it also functions as a scaffold protein required for Cdc42 activation. This G beta gamma-PAK1/PIX alpha/Cdc42 pathway is essential for the localization of F-actin formation to the leading edge, the exclusion of PTEN from the leading edge, directional sensing, and the persistent directional migration of chemotactic leukocytes. Although ligand-induced production of PIP(3) is not required for activation of this pathway, PIP(3) appears to localize the activation of Cdc42 by the pathway.

Actins↗