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Biomedical subjects

X Liu

Publications and source records attributed to X Liu.

At least 631 records · Page 35Linked to original sources
PubMed2000

[Evaluation of red cell mean corpuscular volume and simple tube red cell osmotic fragility quantitative test in detection of thalassemia].

OBJECTIVE: To evaluate and compare the detection efficiency of red cell mean corpuscular volume(MCV) test against simple tube red cell osmotic fragility quantitative test(STROFQT) in diagnosis of thalassemia. METHODS: 1978 subjects (989 couples) were detected by both MCV test and STROFQT, 158 samples from subjects were tested by alpha,beta-thalassemia DNA polymerase chain reaction(PCR) and serum ferritin test. RESULTS: The positive rate (9.0%), sensitivity (98.9%) of MCV test were higher than those of STROFQT (8.1%, 88.6%) (P < 0.05). The specificity of MCV test showed no statistic significance compared with that of STROFQT (P > 0.05). CONCLUSION: Both MCV test and STROFQT served as helpful approaches in detection of thalassemia, MCV test shows better diagnostic efficiency for screening than STROFQT.

Adult↗
PubMed2000

Caerulein-induced pancreatitis in Wistar rats.

We describe a refined model of intravenous caerulein-induced pancreatitis by using osmotic infusion pumps in the conscious unrestrained Wistar rat. The volume of caerulein required for the 6-h infusion is loaded into PE-55 catheter tubing attached to an Alzet (Alza Corporation, Palo Alto, CA) implantable osmotic pump that has been primed with saline. The technique has reliably induced mild edematous pancreatitis, which we verified histologically. Our refined model has the advantages of unrestrained animals, reduced animal handling and acclimation, and decreased cost.

Animals↗
PubMed2000

[Utilization of insoluble phosphate by Larix gmelini seedlings under phosphorus starvation].

The utilization of insoluble phosphate by 2 years old larch(Larix gmelini) seedlings was studied in greenhouse. The seedlings were grown in sand and AlPO4 was supplied as a source of P. The results showed that larch seedlings could utilize some amount of AlPO4. Supplied with AlPO4 but not incubated with mycorrhizal-fungi, the seedlings could absorb 35.1% and 64.9% of the phosphorus uptake when supplied with soluble phosphate. The effects of various mycorrhizal-fungi on utilization of phosphate were different, i.e., the utilization rate of AlPO4 was higher when incubated with Suillus granulatus, but was similar to control when incubated with Suillus grevillei. The proportion of root/crown became higher under P-starvation, and larch seedlings could gain more P by enlarging their root growth.

Aluminum Compounds↗
PubMed2000

[Community characteristics of rare trees at Dalaoling of Three-Gorge reservoir area in western Hubei Province].

The quantitative characteristics, plant frequency in layers and species diversity of David involucrata var. vilnoriniara, Euptlea pleiosperma, Stewartia sinensis and Pterostyrax psilophtila communities at Dalaoling National Forest Park Reserve of Yichang were studied qualitatively and quantitatively. The community composition and structure were made clear, the succession courses and stages of the communities were revealed, and the role of these rare trees on the succession course of communities and the cause of being in imminent danger were analyzed, which provided a theoretical basis for protecting the rare trees in the Three-Gorge reservoir area.

China↗
PubMed2000

[Effects of soil moisture and shading levels on photosynthetic characteristics of cotton leaves].

The effects of different soil moistures and shading levels on stomatal conductance(Gs), net photosynthetic rates(Pn), transpiration and leaf water potential(LWP) of cotton (variety Zhongmian No. 23) grown in pots from the seedling to flower bud stages in summer noon were evaluated. We designed three shading levels: no-shading(CK), 75% shading (DN), 40% shading(SN); and three soil moistures; 85%-100% (high water, HW), 65%-85% (medium water, MW) and 45%-65% (low water, LW) of field water-bolding capacity. The Gs of DN and SN increased by 16.69% and 28.01% compared with CK at HW, respectively, while the Pn of DN and SN declined by 45.74% and 20.54%, respectively. The Gs of DN and SN enhanced by 28.86% and 23.28% compareds with CK at MW, respectively, while the Pn of DN and SN decreased by 31.97% and 1.64%, respectively. The Gs of CK, DN and Sn did not exhibit significant differences at LW, while Pn of DN and SN reduced by 46.22% and 13.45%, respectively. Significant difference in Gs did not exist between DN and SN at the same soil moisture, but there was significant difference in Pa between them (except at LW). It was suggested that Gs declined with the increasing of leaf-to-air vapor pressure difference (VPD) and showed weak correlation with Pn by regression. The combined effects of soil moistures and shading levels on LWP and transpiration rate were not significant. There was no significant difference in LWP and transpiration rate among three shading treatments. Contrasted to treatment CK, intercellular CO2 concentration (Ci) in DN and SN at HW, MW and LW increased significantly, except no apparent change of Ci in SN at MW.

Carbon Dioxide↗
PubMed2000

Vasoactive effects of adrenotensin and its interactions with adrenomedullin.

OBJECTIVE: To investigate the vasoactive effects of adrenotensin and the interactions between adrenotensin and adrenomedullin (ADM). METHODS: Isolated rat aortic tension, rat mean arterial pressure and 3H-TdR incorporation of rat vascular smooth muscle cells were measured. Isolated rat aortas were incubated in K-H solution containing adrenomedullin or adrenotensin. The released adrenotensin or adrenomedullin (in incubation medium) from rat aortas was measured by radioimmunoassay. RESULTS: 1 x 10(-8) and 1 x 10(-7) mol/L adrenotensin augmented rat aortic tension in a dose-dependent manner (P < 0.01). An intravenous bolus injection of adrenotensin (2.5 nmol/kg, i.v.) increased the mean arterial pressure by 28% in anesthetized rats (P < 0.01). 1 x 10(-7) mol/L adrenotensin increased 3H-TdR incorporation in cultured rat vascular smooth muscle cells by 55% (P < 0.01). Adrenomedullin inhibited these activities of adrenotensin to different extents. 1 x 10(-9), 1 x 10(-8) and 1 x 10(-7) mol/L adrenotensin decreased adrenomedullin release rates by 19%, 35% and 46%, respectively (P < 0.05 or P < 0.01) and 1 x 10(-8) mol/L adrenomedullin also inhibited adrenotensin release by 45% from rat aorta (P < 0.01). CONCLUSION: Adrenotensin is a novel peptide that elicits the activities of vasoconstriction, pressor effects and induces the proliferation of vascular smooth muscle cells. There is antagonism in vascular activities and reciprocal inhibition in the release between adrenotensin and adrenomedullin. These interactions are manifestations of intramolecular regulation of proadrenomedullin (Pro-ADM).

Adrenomedullin↗
PubMed2000

Co-modification of IL-2-TNF alpha fusion gene and B7.1 gene to murine breast tumor cells leads to improved tumor rejection and vaccine effect.

OBJECTIVE: To improve the vaccine potency of gene-modified tumor cells. METHODS: Using recombinant adenoviruses, we expressed the B7.1 gene in murine breast tumor cell line EMF6 and a subline previously transfected with retrovirus vector XdF harboring the IL-2-TNF alpha fusion gene. RESULTS: Immunization/challenge experiments demonstrated that IL-2-TNF alpha/B7.1 co-modified tumor cells possessed a lower tumorigenicity in vivo and an improved tumor-specific vaccine potency compared with single gene transfectant (P < 0.05). Three weeks after immunization with a variety of tumor cells, the mixed lymphocyte and tumor cells reaction assay (MLTB) and 51Cr-release assay were performed to test cellular immunity function. The results indicated that IL-2-TNF alpha and B7.1 together induced a more potent antitumor immune response than either molecule alone, 25% higher than IL-2-TNF alpha and 20% higher than B7.1, respectively. CONCLUSION: The IL-2-TNF alpha fusion gene and B7.1 gene act in concert to improve their antitumor effectiveness.

Animals↗
PubMed2000

Co-transfection of MRP and bcl-2 antisense S-oligodeoxynucleotides reduces drug resistance in cisplatin-resistant lung cancer cells.

OBJECTIVE: To detect the influence of antisense s-oligodeoxynucleotides (S-ODNs) of bd-2 and multidrug resistance-associated protein (MRP) genes multidrug resistance-associated protein gene and bcl-2 antisense S-oligodeoxynucleotides on cisplatin-resistant lung adenocarcinoma cell line A549DDP which overexpresses both bcl-2 and MRP. METHODS: A549DDP cells were treated with sense and antisense S-ODN mediated by lipofection. Expression of MRP and bcl-2 mRNA and protein in the treated cells was measured by RT-PCR and flow cytometry (FCM), respectively. Apoptosis was identified by DNA electrophoresis and terminal deoxynucleotidyl transferase (TdT)-mediated biotin dUTP nick end-labeling (TUNEL). The degree of drug resistance of the treated cells was detected by a cell viability 3'-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyl-tefrazolium bromide thiazolylblue (MTT) assay. RESULTS: Expression of bcl-2 and MRP significantly decreased in the cells treated with bcl-2 or/and MRP antisense S-ODN for 48 h as compared to the cells untreated and sense-treated (P < 0.05). Resistance to cisplatin in the cells treated with bcl-2 or/and MRP antisense S-ODN decreased by 60.6% (6.5 times), 56.4% (7.2 times) and 71.0% (4.8 times), respectively, which paralleled the decrease of bcl-2 and MRP expression. Similarly, the resistance to etoposide and epirubicin in antisense-treated cells also reduced in parallel to decreases of the two gene expressions. The drug resistance in sense-treated cells was similar to that in untreated cells. Statistically significant dose- and concentration-dependent increases of apoptotic cells were observed in the groups exposed to 100 mumol/L cisplatin for 48 h after treatment by bcl-2 or/and MRP antisense. CONCLUSION: Bcl-2 and MRP were at least additive and possibly synergistic in conferring drug resistance in a cisplatin-resistant lung adenocarcinoma cell line. Antisense S-ODN could attenuate drug resistance by promoting cells apoptosis, which might lead to a new treatment for patients with non-small cell lung cancers (NSCLCs) who are refractory to conventional chemotherapy.

Adenocarcinoma↗
PubMed2000

[Application of high frequency radiosurgical knife in the treatment of cervical diseases].

OBJECTIVE: To investigate the indication, resection scope of loop electrosurgical excision procedure (LEEP) and pathological characteristics. METHODS: 176 cases with abnormal cytological and colposcopical findings, including cervical intraepithelial neoplasia (CIN) and atypical squamous cells of undermined significance (ASCUS), were studied. Conization of cervix was performed in 63 cases of > or = CIN2, of which 33 cases with LEEP and 30 by traditional electrosurgical knife (TEK) as controls. Cervical biopsy was performed in 113 cases of CIN1 and ASCUS, of which 60 cases by LEEP and 53 by cervical biopsy forceps (CBF) as controls. RESULTS: Three months after conization of cervix the cytological persistent rate of disease was 6.1% in LEEP group and 6.7% in TEK group (P > 0.05). The operation duration of LEEP is (5.0 +/- 0.5) min, and is much shorter than TEK [(15.0 +/- 0.4) min]. The bleeding and recovery time of the cervix are also shorter (P < 0.01). Three months after cervical biopsy the cytological persistent rate of diseases was only 1.7% in LEEP group, significantly less than that in CBF group (35.8%). CONCLUSION: LEEP is indicated to conization of cervix of CIN2-3 and cervical biopsy of CIN1 and ASCUS. It is safe and time-saving. The optimal depth of cervical conization and biopsy was 7 mm and 4 mm respectively in the cervix, and 15 mm and 4 mm respectively in the cervical tube. It can offer intact sample for pathological diagnosis, and has special value for detecting cervical microinvasive carcinoma and local minor carcinoma.

Female↗
PubMed2000

Radionuclide techniques for evaluating dilated cardiomyopathy and ischemic cardiomyopathy.

OBJECTIVE: To assess the clinical significance of radionuclide techniques in evaluating dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (CAD-CM). METHODS: 28 patients with DCM and 55 patients with CAD-CM were studied. All patients underwent 99mTc-MIBI myocardial perfusion SPECT and 18F-FDG myocardial metabolic PET. 78 patients had 99mTc-RBC radionuclide ventriculography and 68 patients had coronary angiography. RESULTS: The results of 23 patients (82%) with DCM showed mild and non-segmental distribution perfusion abnormalities. 52 patients with CAD-CM (95%) showed perfusion abnormalities that distributed along the coronary vessel territories. Significant perfusion defects were found in 4 patients with DCM (14%) and 45 patients with CAD-CM (82%) (P < 0.01). The average perfusion score was 4.5 +/- 2.6 in DCM and 9.6 +/- 2.5 in CAD-CM and the area of diminished perfusion was significantly smaller in DCM than in CAD-CM (P < 0.001). Two patients with DCM and 18 patients with CAD-CM had metabolic defects. The patterns of perfusion/metabolic imaging showed mismatch in most patients with CAD-CM but match in most patients with DCM. The LVEF in patients with DCM and CAD-CM was both decreased but the decreases were not statistically different between DCM and CAD-CM. The RVEF in patients with DCM was significantly lower than that in patients with CAD-CM (32.4% +/- 13.9% vs 40.9% +/- 15.4%, P < 0.05). CONCLUSION: The radionuclide techniques are helpful for distinguishing DCM from CAD-CM. The segmental perfusion abnormality and RVEF are the most important factors for differentiation of DCM from CAD-CM.

Adult↗
PubMed2000

Inhibitory effects of intestinal mucus on bacterial adherence to cultured intestinal epithelial cells after surface burns.

OBJECTIVE: To investigate the relationship between intestinal mucus IgA content and mucus barrier function after surface burns. METHODS: Detection of IgA content in mucus was performed by enzyme linked immunosorbent assay (ELISA) at different time points after burns. Bacterial adherence to cultured epithelial cells (IEC-6) in vitro using E. coli was assessed for each group. RESULTS: The intestinal mucus barrier function declined, parallel to a decrease in IgA content after surface burn in mice. In the normal control group, mucus IgA content was 2.32 D lambda, and 2.51, 1.76, 1.49, 1.06 D lambda at 0.5 h, 1 h, 6 h and 24 h after burn, respectively. Bacterial adherence rate was 0.53 in control group, and 0.46, 0.69, 0.58, 0.81 at 0.5 h, 1 h, 6 h, 24 h after burn, respectively. CONCLUSION: The decrease of intestinal mucus IgA contents is one of the reasons why intestinal mucus barrier function declines after burns.

Animals↗
PubMed2000

Telomerase activity and expression of the telomerase catalytic subunit gene in non-small cell lung cancer: correlation with decreased apoptosis and clinical prognosis.

OBJECTIVE: To investigate the level of telomerase activation (TA) and telomerase catalytic subunit (hEST2) gene mRNA in patients with non-small cell lung cancer, and determine whether they are associated with tumor cell apoptosis, stage, and clinical outcome. METHODS: Primary tumor specimens from 58 patients untreated with chemotherapy and 10 cases of histologically benign and adjacent lung tissue were analyzed. TA and hEST2 were measured by means of a modified telomerase repeat amplification protocol (TRAP) assay and in situ hybridization (ISH), respectively. Terminal deoxynucleotidyl transferase (TdT)-mediated biotin dUTP nick end-labeling (TUNEL) was used to evaluate apoptotic cells. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect bcl-2 mRNA expression. RESULTS: TA and hEST2 were detected in 45 (77.6%) and 43 (74.1%) of 58 tumor specimens, respectively, and not detected in specimens of adjacent and benign lung tissue. One case expressed hEST2 as a weak positive. Statistically significant positive association was found between the level of TA and hEST2 (r = 0.85, P = 0.001). TA and hEST2 were associated with tumor stage, but not associated with tumor grade, gender and patient age. Positive rate of bcl-2 mRNA was 38 (65.5%) of 58 tumor specimens. The mean apoptotic index in the bcl-2 positive group (9.5 +/- 1.3) was lower than that in the bcl-2 negative one (19.8 +/- 2.1, P < 0.05), suggesting that apoptotic index may be inversely associated with bcl-2 expression (r = -0.48, P = 0.041). Bcl-2 expression in the TA and hEST2 positive group (92.1% and 89.4%) was higher than that in the negative one (50.0% and 45.0%, P = 0.043 and P = 0.032, respectively). The apoptotic index was lower in the TA or hEST2 positive group (8.2 +/- 1.4, 10.7 +/- 1.1) than in the negative one (20.5 +/- 1.6, 24.2 +/- 2.1, P < 0.05). A statistically significant inverse association was found between TA or hEST2 and apoptotic index (r = -0.45, P = 0.02 and r = -0.51, P = 0.001, respectively). Positive correlation was also detected between TA or hEST2 and bcl-2 expression (r = 0.86, P = 0.01 and r = 0.73, P = 0.024, respectively). The level of hEST2 mRNA and apoptotic index were associated with clinical outcome in a multivariate cox regression analysis. CONCLUSIONS: High TA and hEST2 were frequently detected in primary non-small cell lung cancer untreated with chemotherapy, having high bcl-2 expression and a low tumor cell apoptotic rate. This suggests that both TA and hEST2 are correlated with the deregulation of apoptosis. hEST2 and apoptotic index have prognostic significance in patients with non-small cell lung cancer.

Adolescent↗
PubMed2000

Angiostatin K(1-3) gene for treatment of human gliomas: an experimental study.

OBJECTIVE: To discuss the feasibility of gene therapy of human glioma by antiangiogenesis method. METHODS: Angiostatin K(1-3) cDNA with secretive signal was inserted into the polylinker sites of eukaryotic expression vector pcDNA3 to construct pcDNA-SAK(1-3). The vector was transfected into human SHG44 glioma cells by lipofectamine and the positive clone was screened by G418. The biological characteristics of glioma cells were examined by electronmicroscope and flow cytometry. The activity of angiostatin K(1-3) protein expressed by SHG44 cells was examined by the bovine micrangium endotheliocyte inhibition assay and immunofluorescence assay. When SHG44 cells were implanted into the strata subcutaneum of nude mice, tumor necrosis and micrangium were calculated immunohistochemically and electronmicroscopically for determining their characteristics and validity in gene therapy of human glioma by antiangiogenesis method. RESULTS: The eukaryotic expression vector pcDNA-SAK (1-3) was successfully constructed and transfected into glioma cells. The cells expressed angiostatin K(1-3) protein, and their tumorigenesis and angiogenesis in nude mice were greatly reduced. CONCLUSION: Angiostatin K(1-3) gene is feasible to treat human glioma. This experiment lays a foundation for gene therapy of the other solid tumors by antiangiogenesis method.

Angiostatins↗
PubMed2000

[Effects of elective cesarean section and antibiotics to the bacterial flora in female genital tract].

OBJECTIVE: To study the effects of elective cesarean section and antibiotics to the bacterial flora in the normal female genital tract. METHODS: Forty-five cases of elective cesarean section were randomly divided into 3 groups: no antibiotic was given (group A), one antibiotic was given for three days (group B), and only once antibiotic was used (group C). Bacterial cultures of vaginal swab and specimens aspirated from uterine cavity were performed in each case before and after operation to supervise the changes of bacterial flora in genital tract and postoperative infection. RESULTS: The positive rate of bacterial culture was 35.71% before operation but 64.29% after operation (P < 0.01). The numbers of aerobe and anaerobe were 3 and 10 strains, respectively, before operation, and 16 and 18 strains after operation. The counts of anaerobe were more than those of aerobe in group A either before or after operation in group A. The counts of aerobe, on the other hand, were more than those of anaerobe both in group B and C after operation. The rates of positive bacterial culture in uterine cavity after operation were similar among the three groups (P > 0.05). Interestingly the operative infection rates were 6.67% evenly. CONCLUSIONS: Both cesarean section and antibiotics may disturb the bacterial flora in the normal female genital tract. The disturbance may increase the chance for flora imbalance and the postoperative infection. There was a great need for rational application of prophylactic antibiotics after cesarean section. Single-dose antibiotic during cesarean section should be advocated.

Anti-Bacterial Agents↗
PubMed2000

[Study on relationship between levels of leptin in maternal blood, amniotic fluid, and umbilical blood and newborn's weight].

OBJECTIVE: To explore the relationship between leptin's quantity in maternal blood, amniotic fluid, umbilical blood and maternal and newborn's weights. METHODS: Levels of leptin in maternal blood, amniotic fluid, and umbilical blood of 34 pregnant women were detected by radioimmunoassay (RIA) method. Results were analyzed by the correlative analysis. RESULTS: (1) Leptin can be detected either from maternal blood or amniotic fluid or umbilical blood. (2) There was an obvious correction between newborn's weight and leptin's quantity of maternal blood (relative coefficient r = 0.53, P < 0.01), amniotic fluid (r = 0.73, P < 0.01) and umbilical blood (r = 0.67, P < 0.01). (3) There was an obvious correction between maternal weight and leptin's quantity of maternal blood (r = 0.61, P < 0.01). (4) There was an obvious correction between leptin's quantity of amniotic fluid and umbilical blood (r = 0.72, P < 0.001). (5) There was not obvious correction between maternal weight and leptin's quantity of amniotic fluid and umbilical blood (r = 0.22, r = 0.18, respectively. P > 0.05). CONCLUSION: It may be of important significance in detection of leptin's quantity in amniotic fluid and maternal blood in pregnant women for predicting the weight and growth of newborns.

Amniotic Fluid↗
PubMed2000

[Clinical value of mediastinoscopy in the diagnosis of mediastinal mass: an analysis of 60 cases].

OBJECTIVE: To study the value of mediastinoscopic examination in the accurate diagnosis of mediastinal mass. METHODS: Standard cervical mediastinoscopy (SCM) or extended mediastinoscopy was applied to patients with mediastinal mass on chest CT or MRI, in order to obtain suspicious tissues at peritracheal, retrosternal, subcarinal, or bilateral hilar areas for pathological study. RESULTS: Of 60 cases in this series, 58 got definite pathological diagnoses. Of the 58 cases, 30 were diagnosed as malignancies, accounting for 51.7% of the cases examined. Twenty-eight of the 58 were diagnosed as benign accounting for 48.3% of them. Small-cell undifferentiated carcinoma was the most common type of malignancy, followed by lymphoma, metastatic adenocarcinoma and squamous cell carcinoma in decreasing frequencies. Over one half of the patients with benign lesions were tuberculosis, followed by sarcoidosis. In this series, 93% of the cases received SCM examination. The most common sampling sites were 2R and 4R areas. CONCLUSION: Mediastinoscopy is a valuable procedure which helps clarify diagnosis of mediastinal mass.

Adolescent↗
PubMed2000

[Expression of LRP, MRP and MDR1 in non-small-cell lung cancer and its clinical significance].

OBJECTIVE: To detect expression of lung resistance protein (LRP), multidrug resistance-associated protein(MRP) and multidrug resistance 1(MDR1) mRNA, and its clinical significance in non-small-cell lung cancer (NSCLC). METHODS: RT-PCR was used to investigate mRNA expression of the above mentioned genes. RESULTS: The frequency of expression of LRP, MRP and MDR1 was 74.2%, 80.3% and 37.9%, respectively. A significant positive correlation was observed between LRP and MRP(r = 0.47, P = 0.001), but this association was found neither between LRP and MDR1, nor between MRP and MDR1. The expression of LRP, MRP and MDR1 did not vary with the grade of cell differentiation and TNM staging. In adenocarcinomas which responded to chemotherapy, there was lowered expression of both LRP and MRP than those which did not respond. In chemo-responsive squamous-cell carcinomas, however, this was true of LRP expression only. The median survival time of NSCLC patients with co-expressed 2 and 3 drug resistance related genes was significantly reduced. CONCLUSION: The intrinsic multidrug resistance of NSCLC involves the combined effects of LRP, MRP and MDR1.

ATP Binding Cassette Transporter, Subfamily B, Mem↗