Search PubMed⌕ Search

Biomedical subjects

Xin Liu

Publications and source records attributed to Xin Liu.

At least 127 records · Page 7Linked to original sources
PubMed2005

[Vaginal paravaginal repair in treatment of severe anterior vaginal prolapse and cystocele].

OBJECTIVE: To explore the rationality, efficacy and safety of vaginal paravaginal repair (VPVR) in treating anterior vaginal prolapse and cystocele. METHODS: Twenty-five consecutive women with stage II to IV and grade II-III anterior vaginal prolapse and cystocele evaluated by pelvic organ prolapse quantification (POP-Q) and Baden-Walker half way system were treated by VPVR. One hundred and one concomitant procedures for reconstructive pelvic surgery were also performed. The VPVR consisted of a thorough entry from the vesicovaginal space under the inferior pubic ramus into the retropubic space, exposing the area of the arcus tendineus fascia pelvis (ATFP), placing nonabsorbable sutures around ATFP on either side and fixed to appropriate locations on the bladder fascia and anterior vaginal walls. Tying of these sutures resulted in dramatic elevation of the lateral superior sulci, as well as prolapsed vesica. Patients were followed up after operation. The cure rate was estimated subjectively and objectively, according to POP-Q and Baden-Walker half way system. RESULTS: All patients had their surgery completed by VPVR. The average operative time was 40 min and estimated blood loss was 70 ml. Two minor intraoperative hemorrhage occurred during dissection of retropubic space and there were no other complications. No morbidity after operation was observed either. Postoperatively, two patients developed obstructive voiding and urinary retention. One recovered completely in a few days, the other has improved slowly for 2 months. Patients were followed up for 2 - 14 months. Two patients with asymptomatic stage I or grade I cystocele were found by examination between 2 and 6 months after operation. Our objective cure rate was 92% and subjective cure rate was 100% respectively at a mean of 6 months after operation. CONCLUSIONS: Since VPVR can restore the normal lateral attachment of the pubocervical fascia to pelvic side wall at ATFP, it is a reasonable, safe and effective procedure to correct severe anterior vaginal prolapse and cystocele.

Aged↗
PubMed2005

[Isolation of the capsid protein gene of maize dwarf mosaic virus and its transformation in maize].

The MDMV (Maize Dwarf Mosaic Virus, MDMV) CP (Coat Protein, CP) gene was cloned by RT-PCR method and introduced into the embryonic calli derived from immature embryos of elite inbred 18-599hong and 18-599bai via particle bombardment. Bombarded calli were selected on selection medium containing 5-10 mg/L (PPT) Bialaphos. From resistant calli, 79 plantlets were regenerated. 18 of 79 were grown and harvested. The results of Southern blotting and PCR analysis demonstrated that MDMV CP have been integrated into the genome of the transgenic plants. PCR-positive progeny plants were artificially inoculated with MDMV strain B, and the average chlorosis of the functional leaves of each plant was investigated. The typical symptoms were observed from the leaves of the control inbreds. while, the presence of the MDMV CP gene provided resistance to inoculation with MDMV strain B.

Capsid Proteins↗
PubMed2005

[Detection of the metabolites of dehydroepiandrosterone in urine with gas chromatography-combustion-isotope ratio mass spectrometry].

AIM: To establish a method to determine the isotope ratios of 13C to 12C of dehydroepiandrosterone and its metabolites in urine, for detecting the source of dehydroepiandrosterone or its metabolites. METHODS: Preliminary separation of endogenous anabolic androgenic steroids could be achieved using solid phase extraction, enzymolysis and thin layer chromatography. The source of dehydroepiandrosterone and other endogenous anabolic androgenic steroids could be detected by their delta values with gas chromat ography-combustion-isotope ratio mass spectrometry. RESULTS: The 5 values of some metabolites of dehydroepiandrosterone reduced after the administration of dehydroepiandrosterone preparation. In these cases the data indicated that exogenous anabolic androgenic steroids were administrated. CONCLUSION: The source of dehydroepiandrosterone or its metabolites in urine could be detected by measuring their delta values with this method.

Adult↗
PubMed2005

[Calcium involved in the signaling pathway of jasmonic acid induced stomatal closure of Vicia faba L].

Ca2+, an ubiquitous second messenger in the signal transudation pathway, is required for various physiological and developmental processes in plant. Jasmonic acid (JA) has been known to induce the stomatal closure. By monitoring the changes of [Ca2+]cyt with fluorescent probe Fluo-3 AM under the confocal microscopy, we observed that exogenous JA increased [Ca2+]cyt in guard cells of Vicia faba L. while the control and linolenic acid (LA), which is a precursor of JA, could hardly affect the change of [Ca2+]cyt. EGTA, a chelator of Ca2+ completely blocked JA-induced stomatal closure. After epidermis pretreated with EGTA, JA failed to result in [Ca2+]cyt increasing. Ruthenium red that blocked Ca2+ released from intracellular Ca2+ store could not significantly change JA-induced stomatal closure, while JA still increased [Ca2+]cyt. Furthermore, Ca2+ channel inhibitor of nifedipine (NIF) reduced the effectiveness of JA-induced stomatal closure and JA-induced increasing fluorescent intensity in guard cells. The results demonstrated that Ca2+ is involved in the signal transduction of JA induced stomatal closure, and the source of [Ca2+]cyt increasing in guard cells induced by JA might derive mainly from the external stores.

Calcium↗
PubMed2005

[Significance of pelvic lymph node human papillomavirus DNA detection in cervical cancer].

OBJECTIVE: To assess the significance of human papillomavirus (HPV) DNA detection in the pelvic lymph nodes in cervical cancer. METHODS: HPV L1 gene fragment was amplified by HPV-specific PCR with general consensus primers from cervical cancer tissues. The types of HPV were identified by sequencing of the PCR product. The relationship between HPV positivity and pathological findings in metastatic pelvic lymph nodes of cervical cancer was analyzed. RESULTS: The positivity rate of HPV DNA was 40% in the pelvic lymph nodes in 40 cases of cervical cancer. HPV DNA was detected in the pelvic lymphatic nodes of all the 10 cases with pathologically confirmed lymph node metastasis of cervical cancer. HPV18 was detected in both of cervical and pelvic lymph nodes in some cases. CONCLUSIONS: HPV DNA can be detected in the pelvic lymph nodes before pathological identification of lymph node metastasis and indicates early pelvic lymph node metastasis of cervical cancer. The presence of HPV18 often indicates high likeliness of lymph node metastasis and suggests poor prognosis of the patients.

Base Sequence↗
PubMed2005

[Sequence polymorphism of human papillomavirus type 16 E7 in cervical cancer].

OBJECTIVE: To explore the genetic polymorphism of E7 open-reading frame of human papillomavirus (HPV) type 16 in cervical cancer. METHODS: The types of HPV was identified by sequence analysis of the PCR product of HPV in cervical cancer tissues. HPV 16 gene fragment in the cervical cancer tissue was amplified by HPV-specific PCR with general consensus primers. RESULTS: The positivity rate of high-risk HPV types in 50 cases of cervical cancers was 78%. Mixed infection of HPV16 and HPV18 was found in 18 cases, and the infection with HPV16 alone occurred in 15 cases. HPV16 E7 was amplified from 25 out of the 34 cases positive for HPV16. A T-to- C change occurred in the 647th nucleotide in the viral nucleotide sequence, causing conversion of the Asn codon of E7 gene into a Ser codon. CONCLUSIONS: The most frequently observed substitution in HPV16 E7 open reading frame occurs in the discrete regions of 647-846, and some substitutions result in the same-sense mutation. The hot-spot mutation of HPV16 E7 in cervical cancers in Guangdong Province occurs at the nucleotide 647 and 846 in the DNA sequence.

Adult↗
PubMed2005

[Effect of indomethacin on fibronectin and plasminogen activator inhibitor-1 in cultured human peritoneal mesothelial cells].

OBJECTIVE: To determine the effect of indomethacin on high concentration glucose and lipopolysaccharide (LPS) induced fibronectin (FN) and plasminogen activator inhibitor-1 (PAI-1) secretion in cultured human peritoneal mesothelial cells. METHODS: Mesothelial cells were isolated from human omental specimens by trypsin disaggregation and incubated by 2.5% glucose or LPS together with different concentrations of indomethacin. Enzyme-linked immunosorbent assay determined the quantity of FN and PAI-1 in the cultured supernatants. RESULTS: Compared with the control group, the levels of FN and PAI-1 in the cultured supernatants were increased significantly exposuring to high concentration glucose and LPS (P <0.01). The different concentrations of indomethacin decreased FN and PAI-1 secretion in the 2.5% glucose or the LPS group within 24 h (P < 0.05). CONCLUSION: Indomethacin can inhibit the synthesis and secretion of extracellular matrix in human peritoneal mesothelial cells, which may be effective in the gene therapy for peritoneal fibrosis.

Cells, Cultured↗
PubMed2005

[Diagnostic methods and clinic application for mtDNA A1555G and GJB2 and SLC26A4 genes in deaf patients].

OBJECTIVE: To establish the method of clinic genetic testing for common deaf genes such as mtDNA nt1555, GJB2 gene and SLC26A4 (Pendrin's syndrome gene, PDS) gene. METHODS: Three hundred and sixty seven sporadic patients with hearing loss from out-patient department of General Hospital of Chinese People's Liberation Army, 60 patients with history of maternal inherited hearing loss from 27 family, 20 congenital deaf patients from special educational school for deaf and dumb, 3 deaf patients with enlarged vestibular aqueduct (EVA) confirmed by CT scan, 50 control individuals with normal bone conductive hearing were analyzed. The genetic testing kit for mtDNA A1555G mutation was used to detect mtDNA A1555G mutation. The whole gene sequencing were accomplished in 20 congenital deaf patients. In 3 patients with EVA, fragments covering all exons of PDS gene were analyzed by denatured high productive liquid chromatogram and special exons were sequenced when DHPLC showed abnormal wave patterns of amplicons covering these exons. RESULTS: Fifty nine patients from 26 family and 5 sporadic patients were found to carry mtDNA A1555G mutation. Among 20 congenital deaf patients, 2 cases were found to have homozygous GJB2 235 del C mutation, 1 case had compound 235del C and 299-300 del AT mutation. Other 2 cases carried heterozygous 109 A-G mutation. Among 3 patients with EVA, 1 case was found to have heterozygous PDS G316X mutation and other 2 cases had homozygous 919-2 A-G mutation. CONCLUSIONS Genetic testing for deafness is feasible procedure with remarkable clinic significance.

Adolescent↗
PubMed2005

[Purification of a ginsenoside-Rb1 hydrolase from Helix snailase].

Through a combination of twice DEAE chromatography by NaCl stepwise and gradient elution with gel filtration chromatography, a kind of ginsenoside-Rb1 hydrolase from crude Helix snailase was separated. The hydrolase was purified to apparent homogeneity on SDS-PAGE. It was estimated that the purified hydrolase was consisted of four identical subunits with a molecular mass of 110-115 kD by SDS-PAGE and gel filtration chromatography. The Km and Vmax values for ginsenoside-Rb1 were calculated to be 0.790 mmol/L and 10.192 micromol/(min x mg) of protein respectively. The ginsenoside-Rb1 hydrolase could only hydrolyze the glycosidic bond at the C20 position of ginsenoside-Rb1 into ginsenoside-Rd.

Animals↗
PubMed2004

Determination of 1-aminocyclopropane-1-carboxylic acid in apple extracts by capillary electrophoresis with laser-induced fluorescence detection.

A rapid and sensitive method for the determination of 1-aminocyclopropane-1-carboxylic acid (ACC) in apple tissues has been described. This method is based on the derivatization of ACC with 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ), and separation and quantification of the resulting FQ-ACC derivative by capillary electrophoresis coupled to laser-induced fluorescence detection (CE-LIF). Our results indicated that ACC derivatized with FQ could be well separated from other interfering amino acids using 20 mM borate buffer (pH 9.35) containing 40 mM sodium dodecyl sulfate and 10 mM Brij 35. The linearity of ACC was determined in the range from 0.05 to 5 microM with a correlation of 0.9967. The concentration detection limit for ACC was 10 nM (signal-to-noise = 3). The sensitivity and selectivity of this described method allows the analysis of ACC in crude apple extracts without extra purification and enrichment procedure.

Amino Acids, Cyclic↗
PubMed2004

Is mRNA and protein level of CD46 altered in measles virus vaccine strain S191-infected cells?

Previous research showed that the expression of measles virus receptor CD46 was downregulated after expression of measles virus hemagglutinin protein on the surface of the virus infected cell or triggered by infected cell-to-cell contact. We reported here that the mRNA level of CD46 in MV infected cells was not changed which was tested by real-time quantitative PCR. To further analyse the surface expression alteration of CD46 after MV infection, flow cytometric analysis and indirect immunofluorescence were used to detect the protein level of CD46. Altogether, our results provided a demonstration that the expression of CD46 was not downregulated by the infection of MV strain S191 both on mRNA level and cellular surface protein level. Previous results reported that the "downregulation" of CD46 expression on the cell surface may take place because H protein masks the antibody recognition site on CD46 which results in "downregulation" of the expression of CD46.

Animals↗
PubMed2004

Deletion of the neuron-specific protein delta-catenin leads to severe cognitive and synaptic dysfunction.

Delta-catenin (delta-catenin) is a neuron-specific catenin, which has been implicated in adhesion and dendritic branching. Moreover, deletions of delta-catenin correlate with the severity of mental retardation in Cri-du-Chat syndrome (CDCS), which may account for 1% of all mentally retarded individuals. Interestingly, delta-catenin was first identified through its interaction with Presenilin-1 (PS1), the molecule most frequently mutated in familial Alzheimer's Disease (FAD). We investigated whether deletion of delta-catenin would be sufficient to cause cognitive dysfunction by generating mice with a targeted mutation of the delta-catenin gene (delta-cat(-/-)). We observed that delta-cat(-/-) animals are viable and have severe impairments in cognitive function. Furthermore, mutant mice display a range of abnormalities in hippocampal short-term and long-term synaptic plasticity. Also, N-cadherin and PSD-95, two proteins that interact with delta-catenin, are significantly reduced in mutant mice. These deficits are severe but specific because delta-cat(-/-) mice display a variety of normal behaviors, exhibit normal baseline synaptic transmission, and have normal levels of the synaptic adherens proteins E-cadherin and beta-catenin. These data reveal a critical role for delta-catenin in brain function and may have important implications for understanding mental retardation syndromes such as Cri-du-Chat and neurodegenerative disorders, such as Alzheimer's disease, that are characterized by cognitive decline.

Analysis of Variance↗
PubMed2004

Determination of phosphoamino acids derivatized with 5-(4,6-dichloro-s-triazin-2-ylamino)fluorescein by micellar electrokinetic chromatography.

A sensitive analytical protocol for determining phosphoamino acids using capillary electrophoresis coupled with laser-induced fluorescence detection has been developed. The technique involved the derivatization of the phosphoamino acids with fluorescent reagent 5-(4,6-dichloro-s-triazin-2-ylamino)fluorescein (DTAF) and the analyses of the derivatives by micellar electrokinetic chromatography with laser induced fluorescence detection (MEKC-LIF). Different variables that affect derivatization (DTAF concentration, pH, temperature and time) and separation (kind of surfactant, pH and concentration of buffer) were studied. The baseline separation of three phosphoamino acids could be obtained in less than 11 min with good reproducibility. There was a linear relationship between the peak area of the analyte and its concentration, with correlation coefficients in the range of 0.9979-0.9997. The concentration detection limits (signal to noise = 3) with respect to each single phosphoamino acid were in the range of 0.5-1 nM. The developed method was successfully applied for the determination of phosphoamino acids in the hydrolyzed phosphorylated protein samples.

Buffers↗
PubMed2004

Regulated transcripts in the hippocampus following transections of the entorhinal afferents.

Based on the data from a cDNA microarray experiment which was carried out to screen the differential expressed genes in the rat hippocampus 10 days after removal of the entorhinal afferents, we confirmed the increase of expression of eight transcripts encoding protein osteonectin, thymosin-beta4, gelsolin, MHC I, MHC II, beta2-microglobulin, and interferon-gamma receptor using Northern blot. In situ hybridization revealed that the up-regulation of all these 8 transcripts localized specifically in the denervated target areas, the hippocampal stratum lacunosum-moleculare, and the dentate outer molecular layer. The results suggest that these molecules may have roles in the plasticity events in the hippocampus after entorhinal deafferentation.

Adaptation, Physiological↗
PubMed2004

Determination of single-cell gene expression in Arabidopsis by capillary electrophoresis with laser induced fluorescence detection.

We report a new method for the measurement of gene expression in single cells of Arabidopsis using capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection. Initially, the quantitative analysis of APETALA2 (AP2) and LEAFY (LFY) was performed by CE-LIF method. The detection limits of AP2 and LFY can reach 0.08 and 0.04 ng/ml (signal-to-noise ratio = 3), respectively. This protocol coupling with single-cell reverse transcriptase-polymerase chain reaction (SC-RT-PCR) has been used to monitor LFY and AP2 expression in individual cells from the shoot apical meristem, leaf, root, and stem of Arabidopsis, simultaneously. The effect of PCR cycle number on PCR product concentrations has been discussed. The changes of LFY expression were determined at single-cell level in different Arabidopsis tissues. The relationship between gibberallic acid (GA) and LFY expression was also revealed by this method. It was shown that the combination between CE-LIF and SC-RT-PCR could provide a highly sensitive and selective tool for the determination of different gene expression at single-cell level in specific tiny plant tissues.

Arabidopsis↗
PubMed2004

Direct sequencing of SARS-coronavirus S and N genes from clinical specimens shows limited variation.

Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) emerged, in November 2002, as a novel agent causing severe respiratory illness. To study sequence variation in the SARS-CoV genome, we determined the nucleic acid sequence of the S and N genes directly from clinical specimens from 10 patients--1 specimen with no matched SARS-CoV isolate, from 2 patients; multiple specimens from 3 patients; and matched clinical-specimen/cell-culture-isolate pairs from 6 patients. We identified 3 nucleotide substitutions that were most likely due to natural variation and 2 substitutions that arose after cell-culture passage of the virus. These data demonstrate the overall stability of the S and N genes of SARS-CoV over 3 months during which a minimum of 4 generations for transmission events occurred. These findings are a part of the expanding investigation of the evolution of how this virus adapts to a new host.

Amino Acid Substitution↗
PubMed2004

K2Ag6Sn3S10: a quaternary sulfide composed of silver sulfide layers pillared by zigzag chains 1infinity[SnS3]2-.

A novel framework K(2)Ag(6)Sn(3)S(10) was synthesized solvothermally and characterized by single-crystal diffraction. The framework comprises [Ag(6)SnS(4)](2+) cationic layers pillared by [SnS(3)](2)(-) zigzag chains formed by vertex-sharing SnS(4) tetrahedra, and potassium ions are located in 1D channels. This compound crystallizes in the orthorhombic Pbcn space group with a = 24.0201(2) A, b = 6.4017(3) A, c = 13.3056(4) A, Z = 4. Its thermal and optical properties are studied.

Journal Article↗