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Biomedical subjects

L Xu

Publications and source records attributed to L Xu.

At least 379 records · Page 21Linked to original sources
PubMed1999

[Study on the relationship between perinatal hypoxia and concentration of endothelin-1 in amniotic fluid].

OBJECTIVE: To investigate the relationship between endothelin-1 (ET-1) concentration in amniotic fluid (AF) and perinatal hypoxia. METHODS: 161 cases were measured for amniotic fluid(AF) ET-1 levels by radioimmunoassay. 110 cases of normal pregnancy were included in control group among which 30 term pregnancies were simultaneously measured for maternal and umbilical plasma ET-1. 51 cases of intrauterine hypoxia were the study group. RESULTS: (1) The AF ET-1 levels showed increasing trend after 14 weeks (P < 0.01). (2) Fetal plasma ET-1 levels were significantly higher than that of maternal plasma ET-1 levels, but lower than those of AF ET-1 (P < 0.01). The ET-1 levels of umbilical plasma had positive correlation with those of AF ET-1 (r = 0.952, P < 0.01), but there is no correlation with levels of maternal plasma ET-1 (r = 0.338, P < 0.05). (3) In study group, the level of AF ET-1 was elevated with severity of hypoxia, the average level of AF ET-1 in cases of intrauterine hypoxia was (30.654 +/- 5.832) ng/L. In cases of severe neonatal asphyxia it was (960.650 +/- 236.698) ng/L. CONCLUSIONS: The ET-1 exists in AF and gradually increases while pregnancy advanced. AF ET-1 levels can be served as a marker to predict perinatal hypoxia.

Adult↗
PubMed1999

[Preliminary study on the relationship between human histocompatibility leukocyte antigen-G mRNA and recurrent spontaneous abortion].

OBJECTIVE: To examine the expression of Human Histocompatibility Leukocyte Antigen-G (HLA-G) mRNA in placenta from cases of recurrent spontaneous abortion (RSA) and try to study the relationship between HLA-G mRNA and RSA. METHODS: In situ hybridization was performed on maternal-fetal interface sections of placenta in first trimester, third trimester of normal pregnancy and RSA women who were treated with immunotherapy and had term delivery. RESULTS: The positive signal of HLA-G expression were showed in all placentas of normal pregnant women within villus and cytoplasma of syncytiotrophoblast and cytotrophoblast. However, there is no any HLA-G mRNA signals in placentas of RSA women after immunotherapy. CONCLUSIONS: HLA-G mRNA is not the main cause of RSA and there is no direct relations to fetal survival.

Abortion, Habitual↗
PubMed1999

[Changes in the mRNA concentration of preprocholecystokinin in rat cerebral cortex and hippocampus after gastric distension].

Cholecyctokinin-octapeptide (CCK-8) is one of the brain-gut peptides widely distributed in neurons of the central nervous system, especially in cerebral cortex and hippocampus. This peptide is thought as a neurotransmitter or modulator. The role of central CCK in the integration of gastric motility and food intake is still unclear. The present investigation was undertaken to see whether the gastric distension exerts some effect on the expression of CCK mRNA in cerebral cortex and hippocampus by means of in situ hybridization and semi-quantitative RT-PCR techniques. The results are as follows. (1) Discrete positive hybridization cells were seen in cerebral cortex and hippocampus in control group. (2) Significant increases of CCK mRNA expression in cerebral cortex and hippocampus produced by gastric distention observed by increased of the volume, the number, the IOD and the SA of positive cells. (3) Amplified bands of the expected size of 158 base pairs were found in cerebral cortex and hippocampus, and signals of gastric distention group were higher than those of control group. The results from RT-PCR assay are in agreement with those based on in situ hybridization. These results imply that biosynthesis of CCK-containing neurons in cerebral cortex and hippocampus is accelerated by afferent signals from gastrointestinal system and may be involved in regulation of gastric motility and food intake.

Animals↗
PubMed1999

Identification of mutation in a candidate gene for hereditary multiple exostoses type II.

OBJECTIVES: To identify possible mutations in our previously cloned candidate gene for hereditary multiple exostoses type II (EXT2) in affected members of EXT families so as to confirm that it is the disease-causing gene. METHODS: The mutation was detected first by single strand conformational polymorphism (SSCP) of all coding exons of the candidate gene and then by sequencing analysis. RESULTS: After analyzing 37 patients from 20 Chinese EXT families by SSCP and DNA sequencing analysis, one 2-bp insertion mutation was identified in this candidate gene in affected members of an EXT family. This mutation resulted in the frameshift and generated a truncated gene product consisting of 105 amino acids. CONCLUSIONS: The identification of the mutation in the candidate gene indicates that this novel gene is responsible for EXT2 (one of the disease-causing gene of EXT).

Amino Acid Sequence↗
PubMed1999

[Modulation of multiple drug resistance by nomegestrol acetate and droloxifene in K562/A02].

OBJECTIVE: To study the modulation of mdr1, glutathione S-transferase Pi (GST pi), topoisomerase II alpha (Topo II alpha) and multidrug resistance-associated protein (MRP) by nomegestrol acetate (NOM) and droloxifene (DRO) in K562 cell line. METHODS: Adriamycin (ADM)-resistant K562 (K562/A02) and parental K562 cells were treated with NOM and DRO. The alterations of chemosensitivity to ADM were evaluated by MTT assay, mRNA and protein expression of drug-resistant gene by RT-PCR and immunohistochemistry and accumulation of ADM by flow cytometry (FCM). RESULTS: Both NOM and DRO markedly enhanced chemosensitivity to ADM of K562/A02 cells. After 20, 10 and 5 mumol/L of NOM or DRO treatment, the chemosensitivities to ADM were increased by 17.7, 15.1 and 5.1 times, respectively in NOM treated cells and by 12.3, 12.9 and 4.0 times, respectively in DRO treated cells. In both the drugs treated cells the accumulation of ADM was increased by 2-3 times. The MDR reversal activity of NOM was similar to that of VRP, but the modulatory action of DRO on K562/A02 cells was weaker than that of VRP at concentration of 20 mumol/L. After 20 mumol/L of NOM treatment, chemosensitivity to ADM of K562 cells was markedly enhanced (P < 0.05). Both NOM and DRO were found to significantly inhibit mdr1 and GST pi expression and increase Topo II alpha expression at the mRNA and protein level. This modulation of gene expression was time dependent and the maximal effects appeared 5 days after drugs treatment. Both NOM and DRO failed to modulate the MRP expression. In K562 cells, NOM and DRO also inhibited GST pi expression (P < 0.05). CONCLUSION: Both NOM and DRO could markedly reverse the MDR of K562/A02 cells. The reversal activity of NOM was comparable to that of VRP. Both the drugs could modulate mdr1, GST pi and Topo II alpha expression in a time dependent manner.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

[ABO-incompatible allogeneic bone marrow transplantation].

OBJECTIVE: To explore the immunohematological problems in ABO-incompatible allogeneic bone marrow transplantation (allo-BMT). METHODS: Among 250 HLA-matched allo-BMTs, 61 were performed between ABO incompatible siblings. Out of these 61 BMTs, 38 were major ABO-incompatible and 23, minor. Control group included 61 HLA-matched Allo-BMTs with ABO compatible grafts. The major ABO incompatible patients received marrow grafts depleted of erythrocytes by hydroxyethyl starch (HES) sedimentation. The minor or bidirectional received marrow grafts depleted of plasma to reduce anti-A or anti-B agglutinins. ABO antigen and antibody in the recipients sera were determined once a week. RESULTS: ABO-incompatible grafts for BMT had no adverse effect on engraftment, recovery of platelets, incidence of GVHD or survival. No recipient developed clinically hemolysis during or after marrow infusion. In ABO major compatible group, the onset of erythropoiesis after BMT was delayed and more RBC transfusions were required. Five of 10 recipients with blood group "O" in this group developed pure red cell aplasia (PRCA), lasting 7-24 months. Two of them recovered without therapeutic intervention. In the PRCA patients, the RBC antibody titers remained high for a longer time after BMT than in those whose erythropoiesis reconstituted timely. Serious morbidity related to ABO incompatibility did not occur. CONCLUSION: ABO-incompatible allo-BMT is fairly safe if there is indication, however, PRCA may develop in isolated cases.

ABO Blood-Group System↗
PubMed1999

[Telomerase activity in breast carcinoma].

OBJECTIVE: To investigate the significance of telomerase activity in breast carcinoma with respect to axillary lymph node status. METHODS: Telomerase activity was analyzed in 88 breast carcinomas specimens and 16 benign breast lesions, using PCR-based telomeric repeat amplification protocol (TRAP) assay. RESULTS: Telomerase activity was detected in 75 (85.2%) of 88 breast carcinomas (including three breast carcinomas in situ which were all positive for telomerase activity), whereas in benign breast lesions analyzed only 2 (12.5%) of 16 cases were positive (P < 0.001). Besides, telomerase activity was significantly higher in node-positive breast carcinomas (93.2%) than in node-negative ones (77.3%, P < 0.05). CONCLUSION: The results suggest that telomerase activation plays an important role during breast carcinoma progression. It may serve as an early marker of breast carcinoma.

Biomarkers, Tumor↗
PubMed1999

[Study of low-fusing porcelain fused to Ti-75 alloy].

OBJECTIVE: To study the feasibility of low-fusing porcelain fused to Ti-75 alloy. METHODS: The bond strength and interfacial state of porcelain-titanium were observed by EPM analysis and shear test. RESULTS: The results showed that the shear bond strength of low-fusing porcelain fused with Ti-75 alloy and the conventional porcelain fused to base metal alloy (NC-VMK68) respectively were 47.38 +/- 7.95 MPa and 48.50 +/- 7.60 MPa. There were no significant difference in the shear bond strength between the two results (P > 0.05). The analysis of electron microprobe showed that there was no crack in the interface, the low-fusing porcelain permeated Ti-75 alloy fairly, and titanium diffused from Ti-75 alloy to porcelain, and silicon, stannum diffused from porcelain to Ti-75 alloy. CONCLUSION: Ti-75 alloy can be regarded as a suitable alloy for low-fusing porcelain.

Dental Alloys↗
PubMed1999

[Study on masticatory muscles and tooth long axis of miniature pigs].

OBJECTIVE: The similarities of masticatory muscles and teeth orientations between miniature pigs and human beings were studied in order to evaluate the use of miniature pigs in oral biomechanics research. METHODS: By means of anatomy, the shapes, start-stop points and orientations of muscle of major masticatory muscles of miniature pigs were measured. Inclination of upper and lower teeth long axis was studied with lateral xray film of mandibles. RESULTS: The main masticatory muscles of miniature pigs include masseter muscle, temptory muscle, lateral pterygoid muscle, medial pterygoid muscle and zygomaticomandibular muscle. The angles of masticatory muscles and base plane are 63.9 degrees in massater muscle, 114.55 degrees in temple muscle, 64.4 degrees in medial pterygoidp muscle. The long axises of miniature pigs teeth are 6.1 degrees in the upper first molar, 6.5 degrees in the lower first molar, 7.3 degrees in the upper third premolar, 3.8 degrees in the lower third premolar. CONCLUSION: The masticatory muscles of miniature pigs are similar with human being in the shape, start-stop point and orientation of muscle force. The third premolar and the first molar of miniature pigs inclinate mesially, and are similar with the first premolar and the first molar of the human beings. Miniature pigs can be used as an animal models which can explain some problems of gnathostomatic system of human beings.

Animals↗
PubMed1999

[The effect of anti-transforming growth factor-beta1 antibody on fibroblast proliferation in vitro].

OBJECTIVE: Using anti-transforming growth factor-beta(1) antibody binding to transforming growth factor-beta(1) (TGF-beta(1)) in conditioned supernatant obtained from alveolar macrophages (AM) in broncho-alveolar lavage fluid (BALF) in bleomycin-induced rats, we investigated the effect of binding of TGF beta(1) to anti-TGF beta(1) antibody on proliferation and synthesis of collagen by fibroblast in pulmonary fibrosis. METHODS: Bleomycin (0.75 mg/100 BW) was instilled intratracheally into wistar rats, then broncho-alveolar lavage (BAL) was performed 7 days later. AMs (5 x 10(5)/ml) were cultured in 0.2% FCS RPMI-1640 medium in vitro for 24 hours and conditioned medium was obtained. L929 fibroblast (7 x 10(3)/well) was cultured in 96-well microtiter plate with conditioned medium and in different doses of anti- TGF beta(1) antibody (1, 5, 10, 20 microg/ml) and IgG for 24 hours respectively. (3)H-Tdr was added 1 microCi per well for 6 hours before culture finished. The proliferation of fibroblast was studied by (3)H-Tdr incorporation rate and synthesis of collagen type IV was tested by ELISA. RESULTS: (1) Fibroblast proliferation which was induced by AM conditioned medium could be significantly depressed by anti-TGF beta(1) antibody in vitro (P < 0.01), and it appeared in a dose-dependent manner. (2) Synthesis of collagen type IV was depressed about 32% by 10 microg/ml anti-TGF beta(1) antibody. CONCLUSIONS: Fibroblast proliferation and collagen synthesis could be depressed by anti-TGF beta(1) antibody in vitro. It seems possible to provide a new way for the treatment of pulmonary fibrosis.

Animals↗
PubMed1999

[The extracellular matrix of optic nerve head in normal human adult].

OBJECTIVE: To demonstrate the macromolecular components of extracellular matrix of lamina cribrosa from young human donors. METHODS: Immunoperoxidase (ABC) staining method was used to investigate the distribution of collagen type IV, laminin and fibronectin in the lamina cribrosa of 7 pairs of normal human eyes. RESULTS: There was a large amount of collagen type IV and laminin in the cribrosa plates, but no positive staining of fibronectin in them. The positive staining of fibronectin only existed at the blood vessel region. CONCLUSION: The lamina cribrosa contains a specialized extracellular matrix of the central nerve system made up of plates of material resembling basement membrane.

Adult↗
PubMed1999

[mRNA and protein expression of apoptosis-regulating gene bcl-x in lymphomas].

OBJECTIVE: To observe mRNA and protein expression of bcl-x and explore the role of bcl-x in the regulation of apoptosis and oncogenesis and their value in differential diagnosis of lymphomas. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) and citric acid-microwave-ABC immunohistochemistry (ICH) were used to observe mRNA transcription forms and protein distributions of bcl-x in 30 frozen tissues and 109 paraffin embedded tissues (both including reactive hyperplasia and common types of lymphoma). RESULTS: RT-PCR revealed that all 30 frozen cases showed bcl-x transcription, of which 29 had bcl-x1 band and 13 had bcl-xs band. Bcl-x1 band was always stronger than bcl-xs band. IHC found that 97/109 cases had fine positive bcl-x granules in the cytoplasm. In lymphoid reactive hyperplasia, bcl-x exhibited weak immunoactivity in cells located in the germinal centers and interfollicular regions of the nodes but not in the mantle zone lymphocytes which surround germinal centers. In lymphomas, bcl-x immunoactivity was always strong and diffuse. The staining fractions in different types of lymphomas were significantly higher than those in lymphoid reactive hyperplasias (P > 0.05), but no significant difference was found between the positive rate and staining fraction of different types of lymphomas. CONCLUSION: Bcl-x shows active mRNA transcription and high protein expression in lymphomas. The long isoform of bcl-x (bcl-xl) is the predominant expression. The characteristics of bcl-x protein expression may be helpful in differential diagnosis of reactive hyperplasia and lymphoma.

Apoptosis↗
PubMed1999

[Affection of aprotinin on tissue factor pathway inhibitor in peri-operation of cardiac direct vision operation].

Twenty patients underwent cardiac operation with cardiopulmonary bypass(CPB). We collected their blood samples during peri-operation and measured tissue factor pathway inhibitor(TFPI) and active coagulation time(ACT). The results were that TFPI and ACT were significantly increased after heparin injection and during CPB. The changes of TFPI and ACT were similar and pathophysiological; it was evident that heparin stimulated TFPI release and ACT prolonged during cardiac operation with CPB. Aprotinin did not affect the change of TFPI. The results suggest that TFPI has the effect on anticoagulation during CPB.

Adolescent↗
PubMed1999

[Study of cleft palate with problems of middle ears and its treatment].

OBJECTIVE: To gain a clear idea of the following: 1. the relationship between the incidence of functional obstruction of middle ear and surgery on cleft palate and patients' age; 2. the bacterial culture of secretion taken from the tympanic cavity with secretory otitis media; 3. the preliminary effects of treatment by inserting a tube into the tympanic cavity of a patient with secretory otitis media. METHODS: 275 middle ears of patients with cleft palate were selected, then acoustic immitence examination and hearing threshold of pure tone were adopted, and bacterial culture was carried out for studying secretion of the middle ear with secretory otitis media. RESULTS: The tympanograms of 75.5% ears of the patients before cleft palate operation were found to be abnormal, among which patients under 3 years were 81%, and 41.2% ears of those after closure of cleft palate were abnormal. Gram's positive and negative germs of bacterial culture were 20.1% and 24% respectively. The hearing of 6 ears with secretory otitis media has recovered from the moderate hearing loss due to tube insertion. And the tympanograms of 4/8 ears were transformed from type B to type A. CONCLUSION: It is beneficial to improve function of Eustachian tube if cleft palate can be repaired at an early stage and beneficial to improve the patients' hearing and devlope their speech if a tube is inserted into the typanic cavity in cases of secretory otitis media at an early stage.

Adolescent↗
PubMed1999

[A computer-aided analysis system for hypertensive retinal image and its clinical application].

With the use of computer image processing technology and microcirculational network analysis technology, we have developed a new system to analyze the outlook of retinal vessles quantitatively. A multimedia structure has been designed for patient's case history file, which includes the basic information of patients, the operating information during sampling and processing patient's retinal image and the result. The system includes image sampling, image displaying, image processing, parameters measuring and analyzing, reports printing and atlas management. Clinical application indicates that the system is useful to hypertension diagnosis.

Aged↗